Base Isolation for Seismic Retrofitting of a Multiple...

Research ArticleBase Isolation for Seismic Retrofitting of a Multiple BuildingStructure Design Construction and Assessment

Massimiliano Ferraioli and Alberto Mandara

Department of Civil Engineering Design Building and Environment Second University of Naples Via Roma 29Aversa 81031 Campania Italy

Correspondence should be addressed to Massimiliano Ferraioli massimilianoferraioliunina2it

Received 22 April 2016 Revised 21 July 2016 Accepted 16 October 2016 Published 22 January 2017

Academic Editor Alessandro Palmeri

Copyright copy 2017 Massimiliano Ferraioli and Alberto Mandara This is an open access article distributed under the CreativeCommons Attribution License which permits unrestricted use distribution and reproduction in any medium provided theoriginal work is properly cited

The paper deals with the seismic retrofit of a multiple building structure belonging to the Hospital Centre of Avellino (Italy) Atfirst the paper presents the preliminary investigations the in situ measurements and laboratory tests and the seismic assessmentof the existing fixed-base structures Having studied different strategies base isolation proved to be the more appropriate also forthe possibility offered by the geometry of the building to easily create an isolation interface at the ground level The paper presentsthe design project the construction process and the details of the isolation intervention Some specific issues of base isolationfor seismic retrofitting of multiple building structures were lightened Finally the seismic assessment of the base-isolated buildingwas carried out The seismic response was evaluated through nonlinear time-history analysis using the well-known Bouc-Wenmodel as the constitutive law of the isolation bearings For reliable dynamic analyses a suite of natural accelerograms compatiblewith acceleration spectra of Italian Code was first selected and then applied along both horizontal directions The results werefinally used to address some of the critical issues of the seismic response of the base-isolated multiple building structure accidentaltorsional effects and potential poundings during strong earthquakes

1 Introduction

A new interest in seismic isolation in Italy was created bysome strong earthquakes (Umbria-Marche 1997 Molise-Puglia 2002 Abruzzo 2009 Emilia 2012) as well as thepublishing of the new Italian Code [1] The evolution ofseismic codes in Italy after the recent Italian earthquakes ledto a general increase of the design seismic actions Nowadaysmany strategic buildings cannot resist strong earthquakesthat however may occur many times during its lifetimesince the return period of the design seismic event is verylong On the other hand the Italian Code [1] like theEurocode 8 [2] now contains two chapters devoted to theseismic isolation of buildings and bridges This situationproduced a significant effect in promoting the general appli-cation of seismic isolation not only to schools hospitalsand emergency management centres but also to ordinaryresidential and commercial buildings Many studies in theliterature focused on the performance of buildings protectedby isolators eithermade of rubber (elastomeric bearings with

or without lead cores) [3ndash6] or based on sliding surfaces(friction-pendulum type bearings) Originally proposed byZayas et al [7] the friction-pendulum system (FPS) wasextended to devices with multiple independent mechanismsA first generation of friction concave isolators consisted ofa spherical concave sliding surface that produces a constantvibration period for the isolated structure depending on thecurvature radius of the sliding surface Multiple pendulumsbearings such as Double and Triple Friction Pendulum (DFPand TFP) were developed in such a way to exhibit adaptivebehavior under different hazard level of earthquakes owingto multiple sliding surfaces In fact in spite of being fullypassive device these bearings allow choosing a desirablecombination of stiffness and damping in certain levels ofexcitation simply selecting the radii of curvature the frictioncoefficients and the displacement capacities of each concavesurface [8ndash12] Jangid [13] investigated the analytical seismicresponse of multistorey buildings isolated by the friction-pendulum system (FPS) under near-fault motions Tsai et al

HindawiMathematical Problems in EngineeringVolume 2017 Article ID 4645834 24 pageshttpsdoiorg10115520174645834

2 Mathematical Problems in Engineering

[14] proposed an advanced analytical model based on theviscoplasticity theory and rigorous finite element derivationsfor the Multiple Friction-Pendulum System Becker andMahin [15] developed complex models capable of simulatingthe bidirectional shear behavior of TFP isolators Nowadaysthe advantages of seismic isolation compared to conventionalstrengthening methods are universally recognized Thesemethods generally include adding new structural elementsand enlarging the existing members The addition of shearwalls and bracings is the most popular strengtheningmethoddue to its effectiveness and lower overall project cost com-pared to the column and beam jacketing However thetypical effect of these conventional strengthening methodsis the increase in both the stiffness and the lateral loadcapacity of the structure As stiffness increases so does thestrength this approach leads to larger mechanism forcesin nonductile members and foundations Furthermore dueto the increased stiffness which translates into a decreasedfundamental period the seismic demand on the structure isalso increased In fact the period shortening of the structuregenerally increases the seismic demand except in the caseof low-rise buildings that fail in the constant-accelerationregion of the response spectrum Thus the capacity increaseis partly alleviated by the increase in seismic demand andthe overall performance of the structure is improved slightlyAs an alternative seismic isolation and supplemental energydissipation are recognized as the two main effective meth-ods to reducing the dynamic responses of structures whensubjected to earthquakes without increasing their globalstiffness Base isolation [16] lengthens the natural period ofthe structure away from the predominant frequency of thegroundmotionsThus it reduces the transmitted accelerationinto the superstructure that is the part of the structure whichis isolated and is located above the isolation interface Sup-plemental energy dissipation devices were shown effective inreducing the building deformation response through increas-ing the structurersquos effective damping This not only providessafety against collapse but also largely reduces damage whichis fundamental for facilities that should remain operationalafter severe earthquakes such as emergency centres firestations and hospitals Furthermore unlike other seismicretrofit methods the seismic isolation retrofit work can beexecuted without changing neither the design nor space of abuilding and the installation of isolators can bemadewithoutresettlement of the occupants Thus the seismic isolationbecame a very popular earthquake-resistant technique forseismic retrofitting of existing buildings The advantages ofthis technique were shown by experimental work [17 18] andby their successful response during earthquakes [19ndash21] Sev-eral numerical and experimental studies definitely demon-strated the applicability and potentials of base isolation for theseismic retrofit of buildings not designed towithstand seismicaction [22 23] More importantly there are many examplesof application of seismic isolation for the retrofit of existingbuildings throughout the world However there are relativelyfew papers available in the literature where the torsionalresponse of base-isolated buildings was studied The evalu-ation of the torsional effects can be particularly important incase of multiple buildings on a common isolation basement

with the isolation system below [24] This situation occursin long base-isolated buildings in which the superstructureconsists of several buildings separated by thermal expansionjoints and all isolation bearings supporting adjacent buildingsare connected together at their top forming a commonisolation system In this case the torsional characteristics ofthe combined system may result in a significant increase ofthe inelastic deformations of the corner bearings and in anout-of-phase motion with possible impact of adjacent partsof the superstructure Often the isolation system is designedby simply ignoring torsion in the superstructure or perhapsby considering it only as a secondary effect Only in recentyears a series of new studies were carried out on multistoreybuilding models Tena-Colunga and Zambrana-Rojas [25]showed that a greater eccentricity of the base isolation systemhas an even more negative base displacements effect thanthe superstructure eccentricity In [26] it is pointed out thathigher torsional amplifications can be expected in the caseof a mass eccentric structure than in the case of stiffnesseccentric structures Kilar and Koren [5] studied the behaviorof base-isolated asymmetric structures with different plandistribution of the isolators Seguin et al [27] developed asystematic method for the optimal torsional control Wolffet al [28] showed that the measured torsional amplificationratios correspond to accidental eccentricities of about halfof the code-described value of 5 percent of largest plandimension

This paper deals with the retrofitting by base isolationof an existing building belonging to the Hospital Centerof Avellino (Italy) The building was composed of threereinforced concrete structures that are linked functionally butstructurally separated to avoid pounding The conventionalstrengtheningmethods used for seismic retrofitting generallyinclude addition of shear walls and proving adequate seismicgaps between structures In this way the three structureswould be stiffened and well separated to avoid poundingduring strong earthquakes As an alternative in the casestudy the three structures were unstiffened using base iso-lation and joined together at the ground floor After retrofitthe three existing structures become a single multiple build-ing structure thus dealing with specific issues concerningdesign construction accidental torsional and poundingseffects

2 Original Fixed-Base Structures

21 General Description The case study is a 5-storey hospitalbuilding of the new hospital campus of Avellino in Campania(Italy)The construction of the buildingwas never completedand only the reinforced concrete skeleton structures wereerected (Figure 1)Thebuildingwas designed after the Irpino-Lucano earthquake of 1980 according to the provisions of theItalian Seismic Code of 1986 [29] The site belongs to the IIseismic category zone whose coefficient of seismic intensityis119862 = 007The importance factor 119868 = 140was considered toincrease the seismic design forces for critical structures basedon the structural occupancy categoryThe response spectrummethod of seismic analysis was applied for prediction offorces in structural members The allowable stress design

Mathematical Problems in Engineering 3

Figure 1 View of the original fixed-base building

method (also called working stress design method) was usedin design In the meantime the design acceleration given bythe last Italian Code [1] for the construction site has beensignificantly increased Thus the seismic resistance of thesestructures has been found to be well below current standardsThe original fixed-base (FB) five-storey building is presentedin Figure 2 The building was composed of three reinforcedconcrete frame structures (named A B and C) The requiredseparations between these adjacent structures were created toavoid pounding during earthquakesThe cross sections of thestructural members are reported below (Figure 2) StructureA beams 35 times 60 cm first-floor columns 50 times 70 cm andother columns 35 times 70 cm Structure B and Structure Cfirst-floor beams 45 times 60 cm other beams 35 times 60 cm andcolumns 35 times 70 cm All the beams of foundation have thesame T-shaped cross section with the following geometryheight = 130 cm flange thickness = 40 cm flange width =145 cm and web thickness = 110 cm in dilatation joint and60 cm otherwise The floors have a mixed structure made upof reinforced concrete and brickTheir thickness is 21 cmThereinforced concrete retaining walls are disconnected fromboth structures in elevation and foundations

22 In Situ Measurements and Laboratory Tests The inputdata were collected from a variety of sources includingavailable documentation and in situ and laboratory measure-ments and tests In particular the following investigationswere carried out (1) geometrical measurements (2) soilinvestigations including sampling and testing (3) determi-nation of mechanical properties of materials by testing ofsamples taken from the structureThe soil comprises depositsof heterogeneous clasts in clay matrix of yellowish greencolourThemechanical properties of soil and the ground typeaccording to soil classification of Eurocode 8 [2] were derivedfrom the following geological and geotechnical tests (1) N6soil profile test N5 Standard PenetrationTests (SPT) andN1Down-Hole Test The synthesis of results from Down-HoleTest gives the following values of the propagation velocity of119878-waves 119881119878 = 149ms in the first 45m of the soil profile

119881119878 = 474ms in the subsequent 30m These results givepromise that soils can be classified as follows ground typeB (360 lt 11988111987830 lt 800 where 11988111987830 is the average value ofpropagation velocity of 119878 waves in the upper 30m of thesoil profile at shear strain) The building is situated on aflat ground (topographic amplification factor 119878119879 = 100) Inassessing the earthquake resistance of the existing structuresthe last Italian Code [1] was applied For the purpose ofchoosing the admissible type of analysis and the appropriateconfidence factor (CF) the following three knowledge levelsare defined in this Code KL1 limited knowledge KL2normal knowledge KL3 full knowledge In the case studythe level of knowledge attained is KL3 (full knowledge)The geometry was known from original outline constructiondrawings with sample visual survey The structural detailswere known from original detailed construction drawingswith limited in situ inspection The information on themechanical properties of the construction materials wasknown from original test reports and limited in situ testingAccording to the Italian Code [1] the limited programmeof in situ testing requires at least one steel material sampleper floor for each type of member (beam column and wall)Moreover the Italian Code also recommends one concretematerial sample per floor for every 300m2 of buildingrsquos totalfloor area Therefore according to the dimensions in plan ofthe building at least N3 concrete material samples per floorfor each type of member were required Some destructivetests (no more than 50) were replaced with a larger amount(at least three times) of nondestructive ultrasonic testingThe numbers of specimens were selected considering a singlebuilding since the floors of the three structures were builtsimultaneously In the same way the mean values of thecompressive strength of concrete and the tensile strength ofsteel were calculated using all the values from the in situtesting In any case the programme of in situ testing wasorganized in order to have at least N1 concrete materialsample per floor for each structure (A B and C) and type ofmemberThe testing campaign included (1) N12 monotoniccompressive tests on cylindrical specimens (2) N18 tensiletests on steel rebar (3) N46 ultrasonic tests combined withSchmidt rebound hammer tests (4) radiographic tests Basedon the results of monotonic compressive tests the followingvalues of the compressive strength of concrete (119891119888) werecalculated mean value 119891119888119898 = 3986MPa minimum value =3332MPa maximum value = 5058MPa standard deviation= 4967MPa coefficient of variation = 01246Themean valuefrom the combined Sonreb method was 3845MPa Based onthe results of tensile tests on steel rebar the following valuesof the tensile strength of steel rebar (119891119910) were obtained meanvalue 119891119910119898 = 563MPa minimum value = 48407 maximumvalue = 55961 standard deviation = 2322 coefficient ofvariation = 00441 According to Italian Standard [1] andEurocode 8 [2] the concrete compressive strength and tensilestrength of steel rebar were obtained as mean values fromin situ tests appropriately divided by the confidence factorsCF accounting for the level of knowledge attained In thecase study the level of knowledge attained is KL3 (fullknowledge) Thus the correspondent confidence factors isCF = 100


39243

39578

39913

40248

40583

40918

41243

PIASTRA

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

456

0

8

16

24

32

79

80

81

83

85

86

87

89

91

92

93

95

97

98

99

101

103

104

105

1074560

4560

4560

4560

456

0

456

0

456

0

456

0

456

0

456

0

C

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

1st floor

2nd floor

3rd floor

4th floor

5th floor

Top floor stair tower

Ground floor

325

335

335

335

335

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

45604560

4560

456045604560 4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

3560

356

0

35603560

3560

3560

3560

3560

3560

3560

3560

3560

3560

356

035

60

356

0

356

035

60

356

0

356

035

60

456

045

60

456

045

60

456

045

60

456

0

2 3 4 5 6 7

10 11 12 13 14 15

18 19 20 21 22 23

25 26 27 28 29 30 31

53

55

56

57

59

61

62

63

65

67

68

69

71

1

9

17

49

50

51

356

035

60

356

045

60

456

045

60

456

045

60

456

045

60

A B

4560

4560

4560

4560

4560

4560

4560

4560

4560

h = 21 cm

4560

4560

BEAMS 45 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 45 times 60

BEAMS 35 times 60

BEAMS 35 times 60

50times70

50times70

50times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

Figure 2 Plan and section view of the original building

23 Seismic Assessment The seismic performance evaluationwas carried out with the procedure reported in Annex B ofEN 1998-3 [2] and in Italian Code [1] The seismic safetyverification was carried out implementing refined models ofthe three reinforced concrete structures in a finite elementcomputer program [30] The design gravity loads were usedin the seismic assessment The permanent gravity loads are(a) 400 kNm2 for the top floor and 580 kNm2 for the otherfloors The values of the live loads are 050 kNm2 for thetop floor and 300 kNm2 for the other floors Using theappropriate coefficients from Eurocode 8 [2] the verticalloads were combined with seismic actions in a combinationof 10 G + 015Q for all the storeys except the top floor whereit was taken equal to 10 G + 030Q Four performance levelswere considered in the analysis Table 1 shows the parametersof the elastic design response spectra according to the ItalianCode [1] The Limit State (LS) of Damage Limitation (DL)was defined by the chord rotation at yielding evaluated bythe formula (A10b) from EN 1998-3 [2] as follows

120579119910 = 120601119910 1198711198813 + 00013 (1 + 15 ℎ119871119881

) + 013120601119910 119889119887119891119910radic119891119888 (1)

where 120601119910 is the yield curvature of the end section 119891119910and 119891119888 are the steel yield stress and the concrete strengthrespectively both in MPa 119889119887 is the (mean) diameter of

Table 1 Parameters of elastic design response spectra [1]

Limit State IO DL LS CPProbability of exceedance 119875119881119877 081 063 010 005Return Period 119879119877 (years) 120 201 1898 2475Peak ground acceleration PGAg 0109 0139 0318 0345Amplification factor 1198650 2346 2350 2470 2489Transition Period 119879119862 (s) 0336 0350 0398 0406

the tension reinforcement The Limit State of DL was alsodefined by drift acceptance criteria related to the performancelevel According to the Damage Limitation requirement ofEurocode 8 [2] the drift ratio was limited to 0005 forbuildings having nonstructural elements of brittle materialsattached to the structure In the same way the Limit Stateof Immediate Occupancy (IO) was defined by a drift thatis assumed as 23 of the drift ratio for the LS of DL TheLimit States of Life Safety (LS) and Collapse Prevention(CP) were verified by comparison between the structuralcapacity and the seismic demand To this aim a nonlinearmodel based on concentrated plasticity was implemented ina finite element computer program [30] The plastic hingemodel is based on the 3D interaction surface which definescoupling between axial (P) and biaxial-bending (M2-M3)


behaviors (PMMhingemodel) Plastic hinge generalised loadagainst deformation diagrams used for the modelling wasconsidered bilinear The elastic stiffness of the bilinear force-deformation relation was equal to the secant stiffness corre-sponding to the initiation of yielding of the reinforcementThe stress-strain model originally proposed by Mander etal [31] was used for confined concrete Confinement factorswere estimated according to Eurocode 8 [2] and variedalong the member length according to the arrangement ofthe transverse reinforcements The steel was modelled withan elastic-plastic-hardening relationship The rigid elementswere placed at beam-column connections to prevent thedevelopment of plastic hinges inside the connections Thecapacity of ductile and brittle members was estimated interms of chord rotation and shear strength respectively Thedeformation capacity of beams and columns was defined interms of the chord rotation The value of the chord rotationcapacity of beam-columnmembers for the Limit State (LS) ofCollapse Prevention (CP) was evaluated by the formula A1from EN 1998-3 [2] as follows

120579119906 = 1120574el 0016 sdot (03]) [max (001 1205961015840)

max (001 120596) 119891119888]0225

sdot (119871119881ℎ )035 25(120572120588119904119909(119891119910119908119891119888)) sdot (125100120588119889) (2)

where 120579119906 is the total chord rotation capacity 120574el is equal to 15for primary seismic elements and 10 for secondary seismicelements ℎ is the depth of cross section 119871119881 = 119872119881 isthe ratio momentshear at the end section ] = 119873(119887ℎ119891119888)is the normalized axial force (119887 = width of compressionzone 119873 = axial force positive for compression) 120596 and1205961015840 are the mechanical reinforcement ratio for the tensionand compression respectively 119891119888 and 119891119910119908 are the concretecompressive strength (MPa) and the steel yield strength(MPa) respectively directly obtained as mean values fromin situ tests appropriately divided by the confidence factorsaccounting for the level of knowledge attained 120588119904119909 =119860 119904119909(119887119908119904ℎ) is ratio of transverse steel parallel to direction119909 of loading (119904ℎ = stirrup spacing) 120588119889 is the steel ratioof diagonal reinforcement in each diagonal direction 120572 isthe confinement effectiveness factor evaluated by formulaA2 from EN 1998-3 [2] The chord rotation relative to theLimit State (LS) of Life Safety (LS) was assumed as 34of the ultimate chord rotation The capacity curve whichrepresents the relation between base shear force and controlnode displacement was determined with the nonlinear static(pushover) analysis in accordance with Italian Code [1] andEurocode 8 [2] The transformation to an equivalent SingleDegree of Freedom (SDOF) system reported in the AnnexB of EN 1998-3 [2] allows plotting the structural capacity(pushover) curve in the ADRS (Acceleration-DisplacementResponse Spectrum) format The capacity acceleration spec-tra of the three existing structures are detailed in Figures 3ndash5According to the Italian Code [1] the pushover analysis wascarried out in two directions (119883 and 119884) The load vectorswere obtained as a product of the floor masses and twochosen profiles of horizontal accelerations (1) First Mode

acceleration profile corresponding to the fundamental mode(2) Uniform (rectangular) constant horizontal accelerationsalong the height of the structure The worldwide assumedcode value of plusmn5 was considered for accidental eccen-tricity Figures 3ndash5 show that a large plastic deformationcapacity is obtained in most of the cases examined sincethe collapse occurs by a global plastic mechanism In somecases a local failure mechanism activates resulting due toformation of plastic hinges in first-storey columns prior tothose in beams This situation typically occurs in the case ofbuilding structures A and C under the uniform distributionof the lateral loads The transformation to an equivalentSingle Degree of Freedom (SDOF) system allows plottingboth capacity and demand in spectral-acceleration versusspectral-displacement coordinates The target displacement119889119905lowast was calculated using the procedure originally proposedby Fajfar [32] and then implemented in Annex B of EC8[2] and Italian Code [1] This procedure is equivalent tothe capacity spectrum method based on inelastic demandspectra [33] if the reduction rule proposed by Vidic et al[34] to obtain the Inelastic Demand Response Spectrum(IDRS) from the ElasticDemandResponse Spectrum (EDRS)is applied This allows comparing capacity and demand inthe spectral plane and calculating the target displacement119889119905lowast for the equivalent SDOF system and the correspondingpeak ground acceleration (PGA) according toAnnex B of EN1998-3 [2] Summarized in Table 1 are the values of the targetdisplacement (119889119905lowast) and peak ground acceleration (PGA) forthe Limit States (LS) of Immediate Occupancy Life Safetyand Collapse Prevention These values represent the capacityof the existing building structures to resist seismic actions interms of peak ground acceleration (PGA) on type A groundcorresponding to the Limit States of the structure (PGA119888

IOPGA119888

DL PGA119888LS) Thus these values may be compared with

the reference peak ground accelerations on type A groundfor the construction site Shown in Table 2 are the values ofPGA corresponding to a return period of 120 years (PGA119889

IOIO Limit State) 201 years (PGA119889

DL DL Limit State) 1898 years(PGA119889

LS LS Limit State) and 2475 years (PGA119889CP CP Limit

State) Figure 6 compares demand and capacity in terms ofPGA The points on the left of the bisector correspond toanalyses for which verification is not satisfied (demand gtcapacity) The points on the right of the bisector correspondto analyses for which verification is satisfied (demand ltcapacity) The preliminary seismic assessment reveals thatthe existing structures generally satisfy the verification ofthe Damage Limitation Limit State (DL) and almost verifythe immediate occupancy requirements On the contrary anunsatisfactory seismic behavior was found for the LS andCO prevention Limit States especially for the structures Aand C depending on their insufficient lateral capacity andlimited ductility More details about the activities carried outto assess the seismic performance of the existing structuresare extensively described in Ferraioli et al [35 36]

3 Seismic Retrofit with Base Isolation

31 Seismic Design The retrofitting of existing buildings maybe carried out with two alternative strategies taking into


Table2Targetdisplacementand

correspo

ndingpeak

grou

ndacceleratio

n(IO

LimitStateDLLimitStateandLS

LimitState)

Capacityof

structureA

Capacityof

structureB

Capacity

ofstructureC

IODL

LSIO

DL

LSIO

DL

LS119889 119905lowast

PGAg

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

First-M

ode+

X+Ecc

160074

350223

174

0374

200081

260196

630374

180085

240218

560374

First-M

odendash

X+Ecc

180079

360241

175

0374

200081

260201

630374

180086

240193

570374

First-M

ode+

XndashEcc

180086

380262

176

0374

200080

260159

630374

180088

230213

560374

First-M

odendash

XndashEcc

160070

320186

168

0374

200081

260200

630374

180088

230226

550374

Uniform

+X+Ecc

200083

400230

540177

220090

300208

710374

200101

270260

650114

Uniform

ndashX+Ecc

200090

410246

540111

220087

290220

710374

200115

270355

650248

Uniform

+XndashEcc

210094

390220

390096

220085

300177

710374

210105

270241

660310

Uniform

ndashXndashEcc

230080

300208

730164

220090

290231

710374

200101

270274

650324

First-M

ode+

Y+Ecc

170097

340229

150

0374

210065

270170

660374

170074

220143

510374

First-M

odendash

Y+Ecc

170083

380276

156

0374

21006

827

0188

660374

150074

200160

470374

First-M

ode+

YndashEcc

170083

370263

155

0374

21006

827

0186

660374

160071

200131

480374

First-M

odendash

YndashEcc

180094

350246

152

0374

210065

270173

660374

170070

220149

510374

Uniform

+Y+Ecc

210105

420276

155

0374

230076

310194

740374

220105

290221

700374

Uniform

ndashY+Ecc

190090

410259

690314

230076

310195

740374

200105

270241

650374

Uniform

+YndashEcc

220090

290254

690349

230074

310184

740374

210101

270191

660374

Uniform

ndashYndashEcc

220105

290271

690334

230074

310196

740374

220105

290274

700374


000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)

Spectral displacement (mm)

+X+Ecc minusX+Ecc+XminusEcc minusXminusEcc

X-DirectionFirst-Mode Distribution

Structure A

250200150100500

XY

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)



X-DirectionUniform Distribution

Structure A

250200150100500

XY

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)


+Y+Ecc minusY+Ecc+YminusEcc minusYminusEcc

Y-DirectionFirst-Mode Distribution

Structure A250200150100500

XY

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)



Y-DirectionUniform Distribution

Structure A

250200150100500

XY

(d)

Figure 3 Capacity acceleration spectra of structure A (accidental eccentricity plusmn5) (a) 119883-Direction First-Mode Distribution (b) 119883-Direction Uniform Distribution (c) 119884-Direction First-Mode Distribution (d) 119884-Direction Uniform Distribution

account the two aspects of seismic design demand and capac-ityThefirst one is based on conventional retrofittingmethodsand include addition of new structural elements (shear walland bracings) to the system enlarging the existing members(column and beam jacketing thickening existing walls)strengthening with steel plate or carbon fiber sheet Thesemethods increase the capacity of the structure (strengthandor stiffness) to meet the likely demand However theseconventional strengthening methods usually increase theacceleration of the buildings by increasing their stiffnessMoreover these conventional strengtheningmethods involveextensive modifications of the building at all levels and theloss of its functionalityThe second strategy for the retrofittingof existing buildings is based on seismic isolation and energydissipation techniques that are methods of reducing thedemands on the structure so that its existing capacity issufficient to withstand the design earthquake Thus mostconstruction work is confined at the level of isolation andthe functionality of the building is maintained Seismicisolation bearings fall into two main categories elastomericbearings and sliding bearings There are two commonlyused types of sliding bearings flat sliding bearings which

are generally used in combination with elastomeric systemsand friction-pendulum (FPS) type bearings The frictionalpendulum system originally proposed by Zayas et al [7]is a sliding seismic isolation system which uses its surfacecurvature to generate the restoring force from the pendulumaction of the weight of the structure The FPS bearingspresent some advantages high rigidity to wind and minorearthquake loads high vertical load capacity and stabilityhigh dissipation and recentreing capacity longevity anddurability characteristics Moreover the natural period ofthe isolated structure is independent by the mass of thesuperstructure as it only depends on the radius of the slidingsurface This is a very important property because it makesthe behavior of FPS bearings nominally independent of axialloadsOn the contrary tomaintain stability of the elastomericbearings under large lateral displacements their diametersbecome large The increase in bearing diameter results instiffer bearings making isolation of light structures difficult

In the case study the application of traditional methodsof seismic retrofitting based on stiffness and strength increasewould raise problems of convergence In fact the periodshortening of the structure increases the seismic demand


000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure BXY

250200150100500

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(d)

Figure 4 Capacity acceleration spectra of structure B (accidental eccentricity plusmn5) (a) 119883-Direction First-Mode Distribution (b) 119883-Direction Uniform Distribution (c) 119884-Direction First-Mode Distribution (d) 119884-Direction Uniform Distribution

Thus the capacity increase would be partly alleviated bythe increase in seismic demand and extensive strengtheninginterventions on structural members would be required tosolve the balance between seismic demand and structurecapacity As an alternative the retrofitting of the existingstructures was based on seismic isolationThe seismic retrofitdesign was carried out by eliminating the seismic separationgap at ground level thus creating a common isolation planeTo this aim beam to beam column to column and slab toslab connections were realized across the separations gapsThe floor slab was strengthened by increasing its depth fromtop and adding 12 times 12 steel rebar wire mesh anchored inthe slabs The isolation bearings were installed after cuttingthe bottom portion of the columns under the ground floorThus the three existing reinforced concrete structures weretransformed in a base-isolated multiple building structure(Figures 7 and 8) The isolation system is composed of 25circular shaped High Damping Rubber Bearings (HDRBs)with three diameters namely 600 650 and 800mm Someplane surfaces steel-teflon (PTFE) Sliding Devices (SDs) werecoupled to HDRBs Figure 9 shows the plan layout of theisolation system The base isolation system is composed of

different rubber bearings The reason is that the diametermust increase with the vertical load to maintain the stabilityof the bearing under large lateral displacementsThe increasein bearing diameter resulted in stiffer bearings making itnecessary to use flat sliding bearings in combination withthe rubber bearings The plan layout of HDRBs and SDs wasselected in such a way as to minimize the torsion effectsdue to any eccentricity between the centre of mass of thesuperstructure and the centre of rigidity of the isolationsystem However since the slenderness ratio 120582 = 119871max119871min(height to base ratio) of the building in plan is 326 theaccidental torsional effects may be anyhow significant Aseismic gap was provided around a seismically isolatedbuilding to facilitate the large relative displacements at theisolation level The stairs and elevators crossing the isolationlevel are usually a key problem in the retrofitting of existingbuildings The main connections between the building andthe ground (such as stairs entryways elevators and pipes)need to be unconnected across the isolation plane or designedto accommodate the displacement of the isolation systemIn the case study the internal stairs and elevators do notcross the isolation interfaceThe external stairways and access


000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(a)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(b)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(c)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)



Y-DirectionMass Distribution

XY

Structure C

300200150100500

(d)

Figure 5 Capacity acceleration spectra of structure C (accidental eccentricity plusmn5) (a) 119883-Direction First-Mode Distribution (b) 119883-Direction Uniform Distribution (c) 119884-Direction First-Mode Distribution (d) 119884-Direction Uniform Distribution

points were detailed to be fixed to the superstructure andbe ldquosimply supportedrdquo on the structure below the isolatorsUtilities and pipes that cross the seismic plane were detailedto move horizontally

The design of the base-isolated structure was based onthe Italian Seismic Code [1] The isolation bearings weremanufactured by FIP Group (Padova Italy) The elastomericisolators are reinforced rubber bearings belonging to theseries SI (FIP SI-S 600180 FIP SI-S 650180 and FIP SI-S 800180) The design displacement was 119889119889119888 = 350mmThe free Sliding Devices are pot-type bearings from Vasoflonseries FIP (VM 200700700 VM 350700700 and 2 timesVM 200700700 for coupled columns) The mechanicalproperties of the isolation rubber bearings used for thesample structure are summarized in Table 3 Qualifying andacceptance testing was carried out on a sample of HDRBs fol-lowing the protocol required by the Italian Seismic Code [1]Table 4 shows the results of the acceptance tests carried out onthe rubber bearings In Figure 10 the shear versus transversedisplacement relationship of the SI-S 800180 rubber bearingunder a sinusoidal displacement history is plotted It is notedthat the HDRBs exhibit stable energy dissipation capacity

at large shear deformations under cyclic loads The force-deformation relationship of the rubber bearings may bedefined assuming an equivalent linear viscoelastic modelIn fact the limitations prescribed by the Italian SeismicCode [1] and Eurocode [2] are met Specifically (a) theeffective stiffness of the isolation system is at least 50 ofthe effective stiffness at 20 of design displacement 119889119889119888(b) the effective damping ratio of the isolation system doesnot exceed 30 (c) the force-displacement characteristicsof the isolation system do not vary by more than 10 dueto the rate of loading or due to the vertical loads (d) theincrease of the restoring force in the isolating system fordisplacement between 05119889119889119888 and 119889119889119888 is at least 25 of thetotal gravity load above the isolating system The responsespectrum method of seismic analysis was applied for pre-diction of forces in structural members The ultimate LimitState design method was used to calculate the strength of thestructure The structural model of the isolated structure isreported in Figure 11 The floor diaphragms were consideredas being rigid in their planes since they have sufficientin-plane stiffness This hypothesis was justified accordingto the Italian Code [1] and Eurocode 8 [2] provisions To


000

010

020

030

040

IO (X-Dir)DL (X-Dir)LS (X-Dir)CP (X-Dir)

IO (Y-Dir)DL (Y-Dir)LS (Y-Dir)CP (Y-Dir)

XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Capacity (PGAcg)040030020010000



Figure 6 Peak ground acceleration on type A ground corresponding to demand (119910-axis) and capacity (119909-axis)Table 3 Nominal properties of rubber bearings

Isolator Type 119881 [kN] 119865119911119889 [kN] 119870119890 [kNmm] 119870V [kNmm] 119863119892 [mm] 119905119890 [mm] ℎ [mm] 119867 [mm] 119885 [mm] 119882 [kg] S1 S2SI-S 600168 1010 5410 067 813 600 168 268 318 850 435 181 345SI-S 650180 1260 6260 074 854 650 180 277 327 700 507 175 350SI-S 800180 3400 13280 112 1506 800 180 281 341 850 835 195 433119881 = maximum vertical seismic load 119865119911119889 = maximum vertical design load in Ultimate Limit State (ULS)119870119890 = effective lateral stiffness119870V = vertical stiffness119863119892 = diameter 119905119890 = total rubber thickness ℎ = total height (not including anchor plates)119867 = total height (including anchor plates)119885 = side length of anchorplates119882 = weight without anchor bolts 1198781 = primary shape factor 1198782 = secondary shape factor

Table 4 Acceptance tests results on rubber bearings

N Isolator Type Vertical stiffness119870V [kNmm]Dynamic shear modulus119866din [MPa]

Static shear modulus119866stat [MPa]

Viscousdamping120585 []

1 SI-S 800180 1508 030 046 1682 SI-S 800180 1524 031 046 1623 SI-S 800180 1501 031 046 1674 SI-S 800180 1512 030 046 1655 SI-S 650180 862 033 045 1626 SI-S 650180 828 030 042 173

Figure 7 View of the hospital building after retrofit

this aim two analyses were carried out one neglecting andthe other considering the diaphragm in-plane flexibility The

diaphragm is considered as rigid because the diaphragmflexibility nowhere increases the horizontal displacementsby more than 10 The high stiffness and strength of thefoundation allowed the foundation-structure interaction tobe neglected Table 5 gives the dynamic properties of theisolated structure (modal period spectral acceleration atvarious Limit States and modal mass ratios 120572119909 and 120572119910 in119909- and 119910-directions) The following damping ratios wereconsidered during linear analysis 120585 = 15 for the three lowermode shapes that are dominated by the isolation system and120585 = 5 for the higher mode shapes that are dominated by thesuperstructure The value of the damping correction factor 120578was determined by the following expression

120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0

Figure 8 Plan and section view of the hospital building after retrofit

Isolation Device FIP SI-S 800180Isolation Device FIP SI-S 600180Isolation Device FIP SI-S 650180

Sliding Device FIP Vasoflon VM 200700700

Sliding Device FIP Vasoflon VM 350700700Sliding Device FIP Vasoflon 2 times VM 200700700

1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2

Figure 9 Plan layout of the isolation system


minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)

Constant compression = 6MPa

3002001000minus100minus200minus300

Figure 10 Shear versus transverse displacement relationship (Seismic Isolator SI-S 800180) Sinusoidal displacement history Results fromdynamic test Loading frequency = 05Hz

Table 5 Dynamic properties of isolated structure

Mode Period (sec) 120585 () 120572119909 () 120572119910 () 119878119886119892 (IO) 119878119886119892 (DL) 119878119886119892 (LS) 119878119886119892 (CP)1 3020 15 000 9998 0032 0044 0100 01122 3014 15 9999 000 0032 0044 0100 01123 2250 15 000 001 0056 0078 0198 02144 0367 5 000 000 0307 0392 0853 09075 0364 5 000 000 0307 0392 0853 09076 0342 5 000 000 0307 0392 0853 09077 0323 5 000 000 0307 0392 0853 09078 0320 5 000 000 0307 0392 0853 0907

Figure 11 Three-dimensional finite element model of base-isolatedmultiple building structure

The design spectrum was scaled down through 120578-factorSpecifically 120585 = 5 in the range 119879 lt 08 119879ISO while 120585 = 15for 119879 ge 08 119879ISO where 119879ISO is the fundamental period of thebase-isolated structure In Figure 12 the design accelerationspectra (a) and design displacement spectrum (b) are plottedIn Figure 13 the roof plan of the first eight mode shapes isplotted It can be observed that the first three mode shapes

are dominated by the isolation system while the other modeshapes are dominated by the superstructure According toItalian Code [1] and Eurocode 8 [2] the behavior factoris taken as being equal to 119902 = 15 for the design ofthe superstructure [37] whereas 119902 = 1 for the design ofisolation system foundation and substructure which is thepart of the structure located under the isolation interfaceand anchored to the foundation The action effects due tothe combination of the horizontal components of the seismicaction were computed using the 10030 percentage rule incompliance with the Italian Seismic Code [1] The analysisof the accidental torsion was carried out considering themethods to be suitably applied in the case of a multiplebuilding structure The accidental eccentricity accounts forinaccuracies in the distribution of masses in the structureDesign codes usually take it into account as an accidentalmass eccentricity that is defined as a fraction of the size ofthe structure This accidental eccentricity may be consideredeither as real mass eccentricity or as additional torsionalactions (simplified method according to the design codes)The principle requirement of Eurocode 8 [2] for accidentaltorsional effects prescribed that the calculated centre of massat each floor 119894 shall be considered displaced from its nominallocation in each direction by an accidental eccentricity

119890119886119894 = plusmn005 119871 119894 (4)

where 119871 119894 is the floor dimension perpendicular to the direc-tion of the acting seismic action On the other side according


000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)

Figure 12 (a) Design acceleration spectra (b) Design displacement spectrum

to both Italian Code [1] and Eurocode 8 [2] the accidentaltorsional effects could be determined as the envelope ofthe effects resulting from the application of static loadingsconsisting of sets of torsional moments119872119886119894 about the verticalaxis of each storey 119894

119872119886119894 = 119890119886119894 sdot 119865119894 (5)

where 119872119886119894 is the torsional moment applied at storey 119894 aboutits vertical axis 119890119886119894 is the accidental eccentricity of storeymass119894 for all relevant directions and 119865119894 is the horizontal forceacting on storey 119894 as derived from the lateral force method ofanalysis In simplified models where the structural eccentric-ity appears explicitly it is very simple to add the accidentaleccentricity in the calculation In complex 3D models thestructural eccentricity does not appear as such and it is there-fore more difficult to account for its effects in such a caseMoreover itmust be observed that both approaches are basedon the hypothesis that the floor diaphragms are rigid whilein the case study the superstructure is composed of threeparts disconnected by separation gaps Thus the applicationof these methods for the evaluation of the torsional effects isnot possible In this paper a 3Dmodel was used for the base-isolated building In this model the mass was generated fromthe load patterns and the accidental eccentricity was takeninto account acting to the mass multipliers so to create therequired additional torsional actions

32 Installation of Isolation Bearings The design idea isto supply this building with seismic isolation by graduallycutting it from its foundation and installing the isolatorson the top of the first storey of the building rather thanthe base of the building (midstorey isolation design) Thistechnique is gaining popularity because it enhances the con-struction feasibility and combines together both aestheticsand functionality The cutting of the columns was carriedout by providing a temporary structure able to transfer theload from the superstructure to the substructure duringthe introduction of the base isolation bearing into the gapThis structure will then be reused for future interventions

of replacement and maintenance of the devices This aspectsuggested to provide an easily transportable provisionalmetalstructure In Figures 14 and 15 some of the installation phasesof the seismic isolation bearings are shown The generalprocedure is to transfer the load from the column to twohydraulic jacks cut the column place the bearing and thentransfer the load from the jacks to the isolator The sequenceof operations for the installation of each bearing is describedas follows

(1) The basement columns were strengthened with athick layer of reinforced concrete C2835 jacketingthem below the section that will be occupied by theisolators (Figure 16) The longitudinal and transversereinforcement were made of steel grade B450C Theanchor bolts were fixed before the concrete casting toattach the bottom steel plate

(2) Epoxy grouted threaded rods are placed in drilledholes in the column to attach the temporary proppingThese anchors will remain in place and can bereused for future interventions ofmaintenance andorreplacement of the devices

(3) The temporary propping was located on hydraulicjacks to take the full axial load of the column

(4) The equipment was attached to measure the load anddeformation sustained by temporary supports

(5) The temporary supports were pushed up usinghydraulic jacks so as to transfer the building weightfrom the column to the temporary supports

(6) The concrete section of the column was demolishedTwo cuts (lower first and then upper) were madethrough the column with a wire saw The wire cutswere carried out through the concrete and steelreinforcing of the column A section of the columnwas isolated to allow space for the base isolationbearing

(7) The steel plates for mounting rubber bearings wereattached to the top and bottom of the cut column


Mode shape dominated by isolation system Mode shape dominated by isolation system

Third-Mode shape torsional

Mode shape dominated by isolation system

Fourth-Mode shape flexural X

Mode shape dominated by superstructure

Fifth-Mode shape flexural Y


Sixth-Mode shape ndash flexural X


Seventh-Mode shape torsional


Eighth-Mode shape torsional


Period 3020 sec

Period 2265 sec

Period 0364 sec

First-Mode shape 1∘ flexural Y

Period 0323 sec Period 0320 sec

Period 0342 sec

Period 0367 sec

Period 3014 secSecond-Mode shape 1∘ flexural X

Figure 13 First eight mode shapes

(8) Where necessary strengthening steel plates wereattached to the section above and below the cutcolumn

(9) The pre-deformed-and-blocked rubber bearings weremounted between the top and bottom steel platesThebase isolation bearing was introduced into the gapwith the use of a trolley The bearing height and levelwere adjusted with screw jacks

(10) The space between the top plate and the upper columnsection and similarly the space between the bottomplate of the bearing and the lower section of thecolumn was filled with cementitious grout

(11) The hydraulic jacks were destressed in the reversesequence of loading to allow the column load tobe applied to the bearing The compression in thebearing was taken up by progressive settlement of thewhole building


Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B

LiftingbracketsHydraulic

jack

Step C Step D

Hole for isolator anchorage

Steel anchorage ringersLifting brackets

Section view A-A

Lifting brackets

Elastomeric rubber isolator

Hydraulic jack

Section view B-B

Isolator anchorageSteel ringers

Hydraulicjack

B B

A A

Levellingmortar

Screw cap

Figure 14 Installation phases of reinforced rubber bearings (courtesy of FIP Group)

(12) The temporary supports were removed

In this project sensors to monitor the displacements duringthe cut of the columns were not used However the bearinginstallation was made one column at a time working fromthe centre of the building towards each end No harmful

differential settlement or cracking of partitions walls due tomovements of surroundingsupporting concrete structureswas observed during the installation phases of the isolationbearings Figures 17 and 18 show the view of the isolationbearings after construction from the underground level andfrom outside respectively Finally it must be pointed out


Figure 15 Strengthening of the basement columns with a thick layer of reinforced concrete jacketing Cutting out the concrete section of thecolumn Transfer of the building weight from the column to the temporary supports Release of hydraulic jacks and transfer of building loadto the rubber bearing


5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140

Corner rebar4Φ16 anchored infoundation beam

Longitudinal rebar5Φ16 anchored infoundation beam

Stirrups Φ810

Perforation Φ24

145 200

040

100

140

Perforation Φ24 Corner rebar4Φ16 anchored infoundation beam


stirrups Φ810

Figure 16 Retrofitting of the columns

Figure 17 View of isolation bearings from the underground level

that the rubber bearings are formed of thin rubber layersand steel plate chemically bonded together and susceptibleto degradation at high temperature Thus these bearings aredecisive in the structurersquos fire safety if directly subjected tothe exposure of potential fire hazard This project did notrequire passive fire protection due to being in a space withouta fire load as is typical in a basement In cases where the fireprotection is required the most cost-effective method is touse fire-rated board materials over metal framing Howevera fire engineering assessment can rationalize or eliminate theneed for fire protection

Figure 18 View of isolation bearings from outside

4 Seismic Assessment

41 Nonlinear Dynamic Analysis The base isolation is a wayof mitigating seismic demands in structuresThus the super-structure should behave elastically or almost rigidly and thenonlinearity should be confined to the isolators However thenonlinear time-history analysis of important base-isolatedstructures is not uncommon and often a nonlinear modelof the superstructure is considered Recent seismic codes[1 2 38ndash40] have specific chapters dedicated to themodelling


and analysis of base-isolated structures According to thesedocuments two methods are proposed to study the inelasticresponse of the structure in elevation (a)Nonlinear ResponseHistory Analysis (b) Nonlinear Static Analysis According toFEMA 356 [38] and UBC 97 [39] the pushover analysis mayalso be used for the seismic analysis of isolated structures Onthe contrary both European standards [2] and Italian SeismicCode [1] do not allow the use of the pushover analysis in thecase of base-isolated buildings while they permit the use oftime-history analysis Moreover it must be observed that thebase-isolated structures are generally nonclassically dampedsince strong differences between the internal mechanism ofenergy dissipation occur Thus as an alternative to directintegration methods the dynamic equilibrium equation maybe uncoupled in the complex modal space The complexmode superposition can give several advantages for theevaluation of seismic response and it was found to becompetitive in terms of computational effort with directintegration methods [41] As an alternative Muscolino etal [42] proposed an improved response spectrum method(RSM) for the seismic analysis and design of building struc-tures with base isolation system This method consists of atwo-stage transformation of coordinates in parallel with aDamping-Adjusted Combination (DAC) rule Thus it avoidsthe calculation of the exact complex-valued eigenpropertiesof base-isolated buildings and reduces computational effortMoreover it addresses the main sources of inaccuracy in thepractical application of the RSM to base-isolated buildingsthat is response spectrum for different viscous dampingratios and combination rule for nonconventional structuresThe direct integration methods may be used for the solutionof the equations of motion whenever they are coupled Thisapproach requires the solution of a system of differentialequations whose size is equal to the total number of degreesof freedom of the structure In this paper the Fast NonlinearAnalysis Method [43] was used for the integration of theequations ofmotionThismethod based on an iterative vectorsuperposition algorithm was found to be extremely efficientin the case of isolated structures since a very limited numberof points in which nonlinear behavior takes place whensubjected to seismic loading occur Moreover significantreductions in processing times were found when comparedwith other nonlinear analysis methods Thus the time-dependent response of the structure was obtained by directnumerical integration of its differential equations of motionThe seismic response was evaluated by means of nonlineartime-history analysis using a constitutive law of the isolationbearings which can adequately reproduce the behavior ofthe system in the range of deformations and velocitiesanticipated in the seismic design situation In particular theconstitutive law of the isolation bearings was approximatedby the well-known Bouc-Wen model [44 45] The seismicmotion consisted of two simultaneously acting accelerogramssimultaneously along both horizontal directions In the caseof base-isolated structures it is possible to use a singleacceleration time-history However in this paper a group of7 pairs of time-histories was applied in accordance with theItalian Code requirements for fixed-base structuresThus theaverage of the response quantities from all the analyses was

000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000

Target spectrum Average spectrum102xa SF = 0431 102ya SF = 0541304xa SF = 0586 304ya SF = 0356330xa SF = 145 330ya SF = 135341xa SF = 118 341ya SF = 138389xa SF = 180 389ya SF = 179391xa SF = 418 391ya SF = 370458xa SF = 100 458ya SF = 112

Figure 19 Spectrum compatibility for the selected records

used as the design value of the seismic effect in the relevantverifications The description of the seismic motion maybe made by using artificial accelerograms and recorded orsimulated accelerograms The recorded accelerograms allowaccounting for characteristics like frequency duration andenergy of real earthquake ground motions The SIMBADdatabase (Selected Input Motions for displacement-BasedAssessment and Design) [46] was used for selecting therecorded accelerograms from different worldwide strongground motion databases [47] The suite of accelerogramsobserved the rules recommended in the seismic standardsIn fact the mean of the zero period spectral responseacceleration values (calculated from the individual time-histories) was not smaller than the value of 119886119892 sdot 119878 for the sitein question where 119886119892 is the design ground acceleration ontype A ground and 119878 is the soil factor Furthermore in therange of periods between 02119879ISO and 12119879ISO no value ofthe mean 5 damping elastic spectrum calculated from alltime-histories was less than 90 of the corresponding valueof the 5 damping elastic response spectrum The recordedaccelerograms considered in the numerical analysis are sum-marized in Table 6 In Figure 19 the spectrum compatibilityfor the selected acceleration records was represented Thesame figure provides the scale factors of the selected groundmotion records

42 Evaluation of Torsional Effects The lateral-torsionalresponse of structures was extensively studied in the liter-ature [5 25ndash27 48ndash52] The effectiveness of base isolationis reduced for a high eccentricity of the superstructureHowever the eccentricity of the superstructure does nothave any significant influence on base displacements Onthe contrary the eccentricity of the centre of mass on theisolation plane may increase the lateral displacement of theisolation devices Although the magnitude of shear and


Table 6 Set of earthquake natural records

Waveform ID Earthquake ID Earthquake name Date 119872119908 PGA119909 [ms2] PGA119910 [ms2]389 149 Christchurch 13062011 60 18787 18872341 142 Christchurch 21022011 62 28548 24537330 137 Darfield 03092003 71 23292 2508102 31 Bam 26122003 66 78338 62357304 94 Loma Prieta 18101989 69 5758 94759458 99 Northridge 17011994 67 33738 3021391 149 Christchurch 13062011 60 08071 091367

minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X

Figure 20 Average of the maximum 119884-displacements (accidentaleccentricity 119890 = +005 119890 = +000 119890 = minus005)

torque generated in an elastomeric isolated structure is lessthan that of the fixed-base structure in general the torsionalamplifications cannot be ignored In particular torsion leadsto significantly increased isolator deformations especially iflarge rotations and large lateral deformations at the centreof mass occur at or very near to the same time duringthe earthquake The main source of torsional motions inseismically isolated buildings is the eccentricity between thecentre of the stiffness of the isolation system and the centreof mass of the structure Furthermore the centre of mass CMshould be shifted creating an eccentricity 119890119871 = plusmn005 that isthe worldwide assumed code value for multistorey buildingsIn this study a complex 3D model was used for the base-isolated building Thus the structural eccentricity does notappear as such and it is therefore more difficult to accountfor its effects Moreover the diaphragmatic behavior at storeylevel in elevation is not ensured since the superstructure iscomposed of three parts disconnected by the separation gapsat each storey Since the mass is generated from the loadpatterns an accidental eccentricity was created acting onthe mass multipliers to deal with these torsional effects InFigure 20 the 119884-displacement pattern of the isolation planeis plotted The analysis results were estimated as the averageof the maximum displacements from the seven pairs of theselected time-histories The results help clarify that torsionaleffects are significant even though the centre of the stiffnessof the isolation system and the centre of mass of the structurealmost coincide In fact the value of the lateral displacement

on the flexible side is greater than 35 compared to thatin the centre of mass of the building This result dependson the high slenderness ratio (height to base ratio) of thebuilding in plan (120582 = 119871max119871min = 326) which increases theaccidental torsional effects In Figure 21(a) a sample plot of119884-displacement versus 119883-displacement of a rubber isolationbearing located on the flexible side is shownThe results referto waveform N389 and accidental eccentricity 119890 = +005In Figure 21(b) a sample plot of the hysteretic response (119884-Shear versus 119884-displacement) of a 800mm rubber isolatoris displaced In Table 7 is summarized the information aboutthe force and displacement in the isolation rubber bearingsThe average of the response quantities from the analysesunder 7 pairs of time-histories was shown In particular themaximumdisplacement in119883- and119884-directions and themax-imum and minimum vertical seismic loads are plotted It canbe observed that theminimum vertical seismic load (119873min) isalways positive This means that the isolation bearings are allin compression for all the load combinations Moreover themaximum vertical seismic load (119873max) is always lower thanthe corresponding nominal value (119881 = maximum verticalseismic load in Table 3) Finally the maximum displacementis always lower than the horizontal design displacement(119889119889119888 = 350mm)

43 Evaluation of Pounding Effects Past earthquakes haverevealed detrimental pounding effects of the seismic perfor-mance of buildings ranging from light local damage to moresevere structural failureThe case study is a multiple buildingstructure with a common ground floor and seismic separa-tion gaps used to separate the three main blocks in elevationThis paper investigates through numerical simulations thepotential poundings of the three adjacent superstructuresTo this aim the live loads were placed on the floors of thethree superstructures in such a way tomaximize the torsionaleffects In particular two different dispositions of the liveloads were used (Figure 22) The relative displacements werecalculated by means of the nonlinear time-history analysisunder the seven pairs of the selected time-histories scaledto the intensity of the Life Safety Limit State The maximumrelative 119909-displacement was computed for the suite of sevennatural ground motions In Figure 22 the average of thelateral displacement in 119883-direction (where pounding canoccur) from all these analyses was plotted The possibilityof poundings between the superstructures A and B may beclearly excluded In fact the maximum relative displacement


Table 7 Force and displacements in isolation rubber bearings

ID Device Displ119883 (m) Displ 119884 (m) 119873max 119873min ID Device Displ119883 (m) Displ 119884 (m) 119873max 119873min

kN kN kN kN71 SI-S 800180 0216 0240 80117 25908 62 SI-S 800180 0221 0232 11413 5934559 SI-S 650180 0216 0224 69318 33063 56 SI-S 650180 0221 0224 90892 5426026 SI-S 600168 0216 0215 70317 38369 14 SI-S 600168 0221 0203 84799 5248228 SI-S 600168 0216 0198 77674 45723 15 SI-S 650180 0221 0206 94008 5737729 SI-S 600168 0216 0199 86394 54440 104 SI-S 800180 0221 0247 12547 7073830 SI-S 600168 0216 0202 87806 55851 67 SI-S 800180 0226 0240 97938 4272231 SI-S 600168 0216 0206 87556 55605 61 SI-S 800180 0226 0231 11346 5821132 SI-S 600168 0216 0211 59179 28216 55 SI-S 650180 0226 0224 85627 4871295 SI-S 650180 0216 0226 66095 29834 2 SI-S 600168 0226 0209 71449 38875107 SI-S 800180 0216 0250 88135 33925 4 SI-S 600168 0226 0198 85078 5250063 SI-S 800180 0219 0232 94771 40243 5 SI-S 600168 0226 0199 95186 6260519 SI-S 600168 0219 0203 80285 48121 6 SI-S 650180 0226 0202 10012 6318923 SI-S 650180 0219 0206 94562 58100 7 SI-S 650180 0226 0206 87276 5035493 SI-S 650180 0219 0226 72278 35818 97 SI-S 800180 0226 0235 10683 51574105 SI-S 800180 0218 0247 11133 56855 103 SI-S 800180 0226 0247 11016 54939

minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)

X‐displacement (m)

Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)

Displacement (mm)030020010000010minus020minus030

(b)

Figure 21 (a) 119884-displacement versus 119883-displacement (b) 119884-Shear versus 119884-displacement Waveform N389 Accidental eccentricity 119890 =+005

(equal to 45mm) is very low if compared to the seismicseparation gap between the adjacent superstructures (equalto 3 cm)

5 Conclusions

The analysis and design of an existing multiple buildingstructure seismic retrofitted by a base isolation system incor-porating rubber bearings and Sliding Devices were presentedin the paper The retrofitting design and the installationphases of the seismic isolation bearings were described indetail The results from nonlinear time-history analysis werereported in this paper The earthquake response analysis of

the hospital building was performed chiefly with reference tothe horizontal displacements of the isolation plane and therelative displacements of the three structures in elevationThevalue of the maximum lateral displacement on the flexibleside of the isolation plane was greater than 35 comparedto that in the centre of mass The results showed significanttorsional effects even though the plan layout of the isolationsystemwas designed in such a way tominimize the eccentric-ity between the centre of mass of the building and the centreof the stiffness of the base isolation system The possibilityof poundings between the adjacent structures in elevationduring strong earthquakes was thoroughly investigated Tothis aim the maximum relative displacement in the direction


800600400200000

1400

1050

700

350

000

Y(m

)

Relative X-displacement (mm)

A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)

Figure 22 Mean of maximum relative119883-displacement between adjacent superstructures

where pounding can occur was compared to the minimumseparation gap required to prevent pounding It was foundthat the maximum relative displacement was very low ifcompared to the seismic separation gap provided between theadjacent superstructures

Compared to traditional retrofitting techniques the seis-mic isolation of the building proved to give several advan-tages First of all the conventional retrofitting methods arebased on the increase of the capacity on the structure in termsof ductility stiffness and strength tomeet the likely demandSo they require addition of new structural elements andstrengthening the existingmembers thus involving extensivemodifications of the building at all levels with the consequentloss of its functionality On the contrary the seismic isolationof the building has reduced the seismic forces demand onthe superstructures and offered a great deal of protection toeverything above the base isolation plane without extensivestrengthening interventions on the structuralmembersMostconstruction work has been confined under the isolationplane thus maintaining the functionality of the building inelevation Moreover the seismic isolation has given a strongreduction of the interstorey drift in superstructures whencompared to the fixed-base structures Thus the width of theseparation gaps has been found quite adequate for protectionagainst pounding Finally it must be pointed out that theanchors in the column to attach the temporary propping haveremained in place andmay be reused for future interventionsofmaintenance andor replacement of the bearingsThemainlimit of the proposed retrofitting technique is that to main-tain stability of the elastomeric bearings under large lateraldisplacements and their diameters are large The increase inbearing diameter has resulted in stiffer bearings making itnecessary to use flat sliding bearings in combination withthe elastomeric bearings Moreover unlike the FPS bearingsthe natural period of the isolated structure depends on the

mass of the superstructure Thus if significant changes of thedesign loads will occur the seismic isolation system built nowwill have to be retrofitted

Notation

119886119892 Design ground acceleration on type Aground119887 Width of compression zone119862 Coefficient of seismic intensity of ItalianCode

CF Confidence factor119889119887 Mean diameter of the tensionreinforcement in rc member119889119889119888 Design displacement of isolation bearing119889119905lowast Target displacement of equivalent SDOFsystem119863119892 Diameter of isolation rubber bearing119890119886119894 Accidental eccentricity119891119888 Concrete compressive strength119891119910 Tensile strength of steel rebar (MPa)119891119888119898 Mean value of concrete compressivestrength119891119910119898 Mean value of tensile strength of steelrebar1198650 Amplification factor119866din Dynamic shear modulus of isolationrubber bearing119866stat Static shear modulus of isolation rubberbearingℎ Total height of isolation rubber bearingwithout anchor plates119867 Total height of isolation rubber bearingwith anchor plates119868 Importance factor


119870119890 Effective lateral stiffness of isolationrubber bearing119870V Vertical stiffness of isolation rubberbearing119871 119894 Floor dimension at storey 119894perpendicularly to the direction of theacting seismic action119871119881 Ratio momentshear at the end section119872119908 Moment magnitude of earthquake groundmotion119872119886119894 Torsional moment applied at storey 119894119873 Axial force (positive for compression)119873max Maximum vertical seismic load inisolation rubber bearing119873min Minimum vertical seismic load inisolation rubber bearing119875119881119877 Probability of exceedance

PGA Peak ground acceleration on type Aground

PGA119889IO Reference peak ground acceleration

demand on type A ground at theImmediate Occupancy (IO) Limit State

PGA119889DL Reference peak ground acceleration

demand on type A ground at the DamageLimitation (DL) Limit State

PGA119889LS Reference peak ground acceleration

demand on type A ground at the LifeSafety (LS) Limit State

PGA119889CP Reference peak ground acceleration

demand on type A ground at the CollapsePrevention (CP) Limit State

PGA119888IO Peak ground acceleration capacity on type

A ground at the Immediate Occupancy(IO) Limit State

PGA119888DL Peak ground acceleration capacity on type

A ground at the Damage Limitation (DL)Limit State

PGA119888LS Peak ground acceleration capacity on type

A ground at the Life Safety (LS) Limit StatePGA119888

CP Peak ground acceleration capacity on typeA ground at the Collapse Prevention (CP)Limit State119904ℎ Stirrup spacing119878119886 Spectral acceleration119878119889 Spectral displacement1198781 Primary shape factor of isolation rubberbearing1198782 Secondary shape factor of isolation rubberbearing119878 Soil factor119878119879 Topographic amplification factor119905119890 Total rubber thickness of isolation bearing119879119862 Transition Period119879ISO Fundamental period of isolated building119879119877 Return period119881 Maximum vertical seismic load119881SLU Maximum vertical design load11988111987830 Average value of propagation velocity of119878-waves in the upper 30m

119882 Weight without anchor bolts of rubberbearing119885 Side length of anchor plates120572 Confinement effectiveness factor120572119909 Modal mass ratio in 119909-direction120572119910 Modal mass ratio in 119910-direction120601119910 Yield curvature of the end section ofbeams and columns120582 Slenderness ratio of the building in plan(height to base ratio)

] Normalized axial force120579119906 Total chord rotation capacity120588119889 Steel ratio of diagonal reinforcement ineach diagonal direction120588119904119909 Ratio of transverse steel parallel to119909-direction of loading120585 Viscous damping ratio120596 Mechanical reinforcement ratio of tensionlongitudinal reinforcement1205961015840 Mechanical reinforcement ratio ofcompression longitudinal reinforcement

Competing Interests

The authors declare that they have no competing interests

Acknowledgments

The author express their personal appreciation for the valu-able assistance given to them in the construction site by FabioFormato and Alberto Maria Avossa (Design Engineers)Giovambattista Aquilino Musto (Construction Manager)Sergio Casarella (Testing Manager) and Vincenzo Botticelli(Technical Manager of MUCAFER Enterprise)

References

[1] NTC 2008 ldquoNorme Tecniche per le Costruzionirdquo DM Infras-trutture Trasporti 14 gennaio 2008 (Italian)

[2] Comite Europeen de Normalisation (CEN) Eurocode 8mdashDesign Provisions for Earthquake Resistance of Structures Euro-pean Communities for Standardization Brussels Belgium2004

[3] S Sorace and G Terenzi ldquoAnalysis design and construction ofa base-isolated multiple building structurerdquo Advances in CivilEngineering vol 2014 Article ID 585429 13 pages 2014

[4] L Di Sarno E Chioccarelli and E Cosenza ldquoSeismic responseanalysis of an irregular base isolated buildingrdquo Bulletin ofEarthquake Engineering vol 9 no 5 pp 1673ndash1702 2011

[5] V Kilar and D Koren ldquoSeismic behaviour of asymmetricbase isolated structures with various distributions of isolatorsrdquoEngineering Structures vol 31 no 4 pp 910ndash921 2009

[6] F Mazza A Vulcano and M Mazza ldquoNonlinear dynamicresponse of RC buildings with different base Isolation systemssubjected to horizontal and vertical components of near-faultgroundmotionsrdquoTheOpen ConstructionampBuilding TechnologyJournal vol 6 pp 373ndash383 2012

[7] V A Zayas S S Low and S A Mahin ldquoThe FPS earthquakeresisting systemrdquo Experimental Report UCBEERC 8701EERC University of California Berkeley Calif USA 1987


[8] AMokhaM Constantinou andA Reinhorn ldquoTeflon bearingsin base isolation I testingrdquo Journal of Structural Engineeringvol 116 no 2 pp 438ndash454 1990

[9] M Constantinou AMokha andA Reinhorn ldquoTeflon bearingsin base isolation II modelingrdquo Journal of Structural Engineer-ing vol 116 no 2 pp 455ndash474 1990

[10] DM Fenz andM C Constantinou ldquoSpherical sliding isolationbearings with adaptive behavior theoryrdquo Earthquake Engineer-ing and Structural Dynamics vol 37 no 2 pp 163ndash183 2008

[11] DM Fenz andM C Constantinou ldquoSpherical sliding isolationbearings with adaptive behavior experimental verificationrdquoEarthquake Engineering and Structural Dynamics vol 37 no 2pp 185ndash205 2008

[12] D M Fenz and M C Constantinou ldquoModeling triple frictionpendulum bearings for response-history analysisrdquo EarthquakeSpectra vol 24 no 4 pp 1011ndash1028 2008

[13] R S Jangid ldquoOptimum friction pendulum system for near-faultmotionsrdquo Engineering Structures vol 27 no 3 pp 349ndash3592005

[14] C S Tsai B-J Chen W S Pong and T-C Chiang ldquoInter-active behavior of structures with multiple friction pendulumisolation system and unbounded foundationsrdquo Advances inStructural Engineering vol 7 no 6 pp 539ndash550 2004

[15] T C Becker and S A Mahin ldquoExperimental and analyticalstudy of the bi-directional behavior of the triple friction pendu-lum isolatorrdquo Earthquake Engineering and Structural Dynamicsvol 41 no 3 pp 355ndash373 2012

[16] F Naeim and J M Kelly Design of Seismic Isolated StructuresJohn Wiley amp Sons New York NY USA 1999

[17] M Dolce D Cardone and F C Ponzo ldquoShaking-table testson reinforced concrete frames with different isolation systemsrdquoEarthquake Engineering amp Structural Dynamics vol 36 no 5pp 573ndash596 2007

[18] C-F Han C-X Li and Q-H Zhang ldquoExperimental seismicstudy of concrete structures with base and roof isolationsystemsrdquo Journal of Earthquake Engineering and EngineeringVibration vol 24 no 1 pp 141ndash147 2004

[19] S Nagarajaiah and S Xiaohong ldquoResponse of base-isolatedUSC hospital building in Northridge earthquakerdquo Journal ofStructural Engineering vol 126 no 10 pp 1177ndash1186 2000

[20] T Fujita Demonstration of Effectiveness of Seismic Isolationin the Hanshin-Awaji Earthquake and Progress of Applicationsof Base-Isolated Buildings Report on the January 1995 KobeEarthquake Institute of Industrial Science University of TokyoTokyo Japan 1999

[21] T Holmes and P Somers ldquoNorthridge earthquake of 17 January1994 reconnaissance reportrdquo Earthquake Spectra vol 11 pp243ndash251 1996

[22] A B M S Islam M Z Jumaat R Ahmmad and K M udDarain ldquoRetrofitting of vulnerable RC structures by base iso-lation techniquerdquo Earthquake and Structures vol 9 no 3 pp603ndash623 2015

[23] V A Matsagar and R S Jangid ldquoBase isolation for seismicretrofitting of structuresrdquo Practice Periodical on StructuralDesign and Construction vol 13 no 4 pp 175ndash185 2008

[24] P C Tsopelas S Nagarajaiah M C Constantinou and A MReinhorn ldquoNonlinear dynamic analysis of multiple buildingbase isolated structuresrdquo Computers amp Structures vol 50 no1 pp 47ndash57 1994

[25] A Tena-Colunga and C Zambrana-Rojas ldquoDynamic torsionalamplifications of base-isolated structures with an eccentric

isolation systemrdquo Engineering Structures vol 28 no 1 pp 72ndash83 2006

[26] A Tena-Colunga and J L Escamilla-Cruz ldquoTorsional ampli-fications in asymmetric base-isolated structuresrdquo EngineeringStructures vol 29 no 2 pp 237ndash247 2007

[27] C E Seguin J L Almazan and J C De la Llera ldquoTorsional bal-ance of seismically isolated asymmetric structuresrdquo EngineeringStructures vol 46 pp 703ndash717 2013

[28] E D Wolff C Ipek M C Constantinou and L MorillasldquoTorsional response of seismically isolated structures revisitedrdquoEngineering Structures vol 59 pp 462ndash468 2014

[29] DM LLPP 24011986MinisterialDecreeNorme tecniche perle costruzioni in zone sismiche 1986 (Italian)

[30] CSIComputerampStructures Inc SAP2000Linear andNonlinearStatic and Dynamic Analysis of Three-Dimensional StructuresCSI Computer amp Structures Inc Berkeley Calif USA 2015

[31] J B Mander M J Priestley and R Park ldquoTheoretical stress-strain model for confined concreterdquo Journal of Structural Engi-neering vol 114 no 8 pp 1804ndash1826 1988

[32] P Fajfar ldquoCapacity spectrummethodbased on inelastic demandspectrardquo Earthquake Engineering and Structural Dynamics vol28 no 9 pp 979ndash993 1999

[33] M Ferraioli A M Avossa A Lavino and A Mandara ldquoAccu-racy of advanced methods for nonlinear static analysis of steelmoment-resisting framesrdquo Open Construction and BuildingTechnology Journal vol 8 pp 310ndash323 2014

[34] T Vidic P Fajfar and M Fischinger ldquoConsistent inelasticdesign spectra strength and displacementrdquo Earthquake Engi-neering amp Structural Dynamics vol 23 no 5 pp 507ndash521 1994

[35] M Ferraioli A M Avossa and F Formato ldquoBase isolationseismic retrofit of a hospital building in Italy design andconstructionrdquo in Proceedings of the Final Conference on COSTAction C26 Urban Habitat Constructions under CatastrophicEvents pp 835ndash840 September 2010

[36] M Ferraioli R Costanzo andA Lavino ldquoBase isolation seismicretrofit of a hospital building in Italy performance underearthquake strong ground motionsrdquo in Proceedings of the FinalConference on COST Action C26 Urban Habitat Constructionsunder Catastrophic Events pp 841ndash846 September 2010

[37] M Ferraioli A Lavino and A Mandara ldquoBehaviour factorof code-designed steel moment-resisting framesrdquo InternationalJournal of Steel Structures vol 14 no 2 pp 243ndash254 2014

[38] Federal Emergency Management Agency Prestandard andCommentary for the Seismic Rehabilitation of Buildings FEMA356 The American Society of Civil Engineers for the FederalEmergencyManagement AgencyWashington DC USA 2000

[39] Uniform Building Code ldquoStructural engineering design provi-sionsrdquo in Proceedings of the International Conference of BuildingOfficials Whittier Calif USA 1997

[40] Federal Emergency Management Agency Recommended Pro-visions for Seismic Regulations for New Buildings and OtherStructures FEMA 450 The Building Seismic Safety Council forthe Federal EmergencyManagement Agency Washington DCUSA 2003

[41] P Malangone and M Ferraioli ldquoA modal procedure for seismicanalysis of non-linear base-isolated multistorey structuresrdquoEarthquake Engineering and Structural Dynamics vol 27 no 4pp 397ndash412 1998

[42] G Muscolino A Palmeri and C Versaci ldquoDamping-adjustedcombination rule for the response spectrum analysis of base-isolated buildingsrdquo Earthquake Engineering and StructuralDynamics vol 42 no 2 pp 163ndash182 2013


[43] P Leger E L Wilson and R W Clough ldquoThe use of loaddependent vectors for dynamic and earthquake analysesrdquo TechRep UCBEERC-8604 Berkeley University 1986

[44] Y-K Wen ldquoMethod for random vibration of hysteretic sys-temsrdquo Journal of Engineering Mechanical Division vol 102 no2 pp 249ndash263 1976

[45] H-G Li and G Meng ldquoNonlinear dynamics of a SDOF oscil-lator with BoucndashWen hysteresisrdquo Chaos Solitons and Fractalsvol 34 no 2 pp 337ndash343 2007

[46] C Smerzini and R Paolucci ldquoResearch Project DPCmdashRELUIS2010-2013rdquo in SIMBAD ADatabase with Selected InputMotionsfor Displacement-Based Assessment and Designmdash2nd ReleaseDepartment of Structural Engineering Politecnico di MilanoMilano Italy 2011

[47] I Iervolino C Galasso and E Cosenza ldquoREXEL computeraided record selection for code-based seismic structural anal-ysisrdquo Bulletin of Earthquake Engineering vol 8 no 2 pp 339ndash362 2010

[48] M Ferraioli ldquoCase study of seismic performance assessment ofirregular RCbuildings hospital structure of Avezzano (LrsquoAquilaItaly)rdquo Earthquake Engineering and Engineering Vibration vol14 no 1 pp 141ndash156 2015

[49] M Ferraioli ldquoInelastic torsional response of an asymmetricplanhospital building in Italyrdquo in Proceedings of the Final ConferenceCOST ACTIONC26 Urban Habitat Constructions under Catas-trophic Events pp 365ndash370 September 2010

[50] M Ferraioli D Abruzzese L Miccoli A Vari and G Di LauroldquoStructural identification from environmental vibration testingof an asymmetric-plan hospital building in Italyrdquo in COSTACTION C26 Urban Habitat Constructions under CatastrophicEventsmdashProceedings of the Final Conference pp 981ndash986 2010

[51] D Basu and S K Jain ldquoSeismic analysis of asymmetric build-ings with flexible floor diaphragmsrdquo Journal of Structural Engi-neering vol 130 no 8 pp 1169ndash1176 2004

[52] M Ferraioli and A Mandara ldquoBase isolation for seismicretrofitting of amultiple building structure evaluation of equiv-alent linearization methodrdquo Mathematical Problems in Engi-neering vol 2016 Article ID 8934196 17 pages 2016

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MathematicsJournal of


Mathematical Problems in Engineering

Hindawi Publishing Corporationhttpwwwhindawicom

Differential EquationsInternational Journal of

Volume 2014

Applied MathematicsJournal of


Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of


Mathematical PhysicsAdvances in

Complex AnalysisJournal of


OptimizationJournal of


CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of


Operations ResearchAdvances in

Journal of


Function Spaces

Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of Mathematics and Mathematical Sciences


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Algebra

Discrete Dynamics in Nature and Society



Decision SciencesAdvances in

Discrete MathematicsJournal of


Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Stochastic AnalysisInternational Journal of


[14] proposed an advanced analytical model based on theviscoplasticity theory and rigorous finite element derivationsfor the Multiple Friction-Pendulum System Becker andMahin [15] developed complex models capable of simulatingthe bidirectional shear behavior of TFP isolators Nowadaysthe advantages of seismic isolation compared to conventionalstrengthening methods are universally recognized Thesemethods generally include adding new structural elementsand enlarging the existing members The addition of shearwalls and bracings is the most popular strengtheningmethoddue to its effectiveness and lower overall project cost com-pared to the column and beam jacketing However thetypical effect of these conventional strengthening methodsis the increase in both the stiffness and the lateral loadcapacity of the structure As stiffness increases so does thestrength this approach leads to larger mechanism forcesin nonductile members and foundations Furthermore dueto the increased stiffness which translates into a decreasedfundamental period the seismic demand on the structure isalso increased In fact the period shortening of the structuregenerally increases the seismic demand except in the caseof low-rise buildings that fail in the constant-accelerationregion of the response spectrum Thus the capacity increaseis partly alleviated by the increase in seismic demand andthe overall performance of the structure is improved slightlyAs an alternative seismic isolation and supplemental energydissipation are recognized as the two main effective meth-ods to reducing the dynamic responses of structures whensubjected to earthquakes without increasing their globalstiffness Base isolation [16] lengthens the natural period ofthe structure away from the predominant frequency of thegroundmotionsThus it reduces the transmitted accelerationinto the superstructure that is the part of the structure whichis isolated and is located above the isolation interface Sup-plemental energy dissipation devices were shown effective inreducing the building deformation response through increas-ing the structurersquos effective damping This not only providessafety against collapse but also largely reduces damage whichis fundamental for facilities that should remain operationalafter severe earthquakes such as emergency centres firestations and hospitals Furthermore unlike other seismicretrofit methods the seismic isolation retrofit work can beexecuted without changing neither the design nor space of abuilding and the installation of isolators can bemadewithoutresettlement of the occupants Thus the seismic isolationbecame a very popular earthquake-resistant technique forseismic retrofitting of existing buildings The advantages ofthis technique were shown by experimental work [17 18] andby their successful response during earthquakes [19ndash21] Sev-eral numerical and experimental studies definitely demon-strated the applicability and potentials of base isolation for theseismic retrofit of buildings not designed towithstand seismicaction [22 23] More importantly there are many examplesof application of seismic isolation for the retrofit of existingbuildings throughout the world However there are relativelyfew papers available in the literature where the torsionalresponse of base-isolated buildings was studied The evalu-ation of the torsional effects can be particularly important incase of multiple buildings on a common isolation basement

with the isolation system below [24] This situation occursin long base-isolated buildings in which the superstructureconsists of several buildings separated by thermal expansionjoints and all isolation bearings supporting adjacent buildingsare connected together at their top forming a commonisolation system In this case the torsional characteristics ofthe combined system may result in a significant increase ofthe inelastic deformations of the corner bearings and in anout-of-phase motion with possible impact of adjacent partsof the superstructure Often the isolation system is designedby simply ignoring torsion in the superstructure or perhapsby considering it only as a secondary effect Only in recentyears a series of new studies were carried out on multistoreybuilding models Tena-Colunga and Zambrana-Rojas [25]showed that a greater eccentricity of the base isolation systemhas an even more negative base displacements effect thanthe superstructure eccentricity In [26] it is pointed out thathigher torsional amplifications can be expected in the caseof a mass eccentric structure than in the case of stiffnesseccentric structures Kilar and Koren [5] studied the behaviorof base-isolated asymmetric structures with different plandistribution of the isolators Seguin et al [27] developed asystematic method for the optimal torsional control Wolffet al [28] showed that the measured torsional amplificationratios correspond to accidental eccentricities of about halfof the code-described value of 5 percent of largest plandimension

This paper deals with the retrofitting by base isolationof an existing building belonging to the Hospital Centerof Avellino (Italy) The building was composed of threereinforced concrete structures that are linked functionally butstructurally separated to avoid pounding The conventionalstrengtheningmethods used for seismic retrofitting generallyinclude addition of shear walls and proving adequate seismicgaps between structures In this way the three structureswould be stiffened and well separated to avoid poundingduring strong earthquakes As an alternative in the casestudy the three structures were unstiffened using base iso-lation and joined together at the ground floor After retrofitthe three existing structures become a single multiple build-ing structure thus dealing with specific issues concerningdesign construction accidental torsional and poundingseffects

2 Original Fixed-Base Structures

21 General Description The case study is a 5-storey hospitalbuilding of the new hospital campus of Avellino in Campania(Italy)The construction of the buildingwas never completedand only the reinforced concrete skeleton structures wereerected (Figure 1)Thebuildingwas designed after the Irpino-Lucano earthquake of 1980 according to the provisions of theItalian Seismic Code of 1986 [29] The site belongs to the IIseismic category zone whose coefficient of seismic intensityis119862 = 007The importance factor 119868 = 140was considered toincrease the seismic design forces for critical structures basedon the structural occupancy categoryThe response spectrummethod of seismic analysis was applied for prediction offorces in structural members The allowable stress design







39243

39578

39913

40248

40583

40918

41243

PIASTRA

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

456

0

8

16

24

32

79

80

81

83

85

86

87

89

91

92

93

95

97

98

99

101

103

104

105

1074560

4560

4560

4560

456

0

456

0

456

0

456

0

456

0

456

0

C

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

1st floor

2nd floor

3rd floor

4th floor

5th floor


Ground floor

325

335

335

335

335

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

45604560

4560

456045604560 4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

3560

356

0

35603560

3560

3560

3560

3560

3560

3560

3560

3560

3560

356

035

60

356

0

356

035

60

356

0

356

035

60

456

045

60

456

045

60

456

045

60

456

0

2 3 4 5 6 7

10 11 12 13 14 15

18 19 20 21 22 23

25 26 27 28 29 30 31

53

55

56

57

59

61

62

63

65

67

68

69

71

1

9

17

49

50

51

356

035

60

356

045

60

456

045

60

456

045

60

456

045

60

A B

4560

4560

4560

4560

4560

4560

4560

4560

4560

h = 21 cm

4560

4560

BEAMS 45 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 45 times 60

BEAMS 35 times 60

BEAMS 35 times 60

50times70

50times70

50times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60



120579119910 = 120601119910 1198711198813 + 00013 (1 + 15 ℎ119871119881

) + 013120601119910 119889119887119891119910radic119891119888 (1)







120579119906 = 1120574el 0016 sdot (03]) [max (001 1205961015840)

max (001 120596) 119891119888]0225

sdot (119871119881ℎ )035 25(120572120588119904119909(119891119910119908119891119888)) sdot (125100120588119889) (2)



IOPGA119888











correspo

ndingpeak

grou

ndacceleratio

n(IO


LimitState)

Capacityof

structureA

Capacityof

structureB

Capacity

ofstructureC

IODL

LSIO

DL

LSIO

DL

LS119889 119905lowast

PGAg

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

First-M

ode+

X+Ecc

160074

350223

174

0374

200081

260196

630374

180085

240218

560374

First-M

odendash

X+Ecc

180079

360241

175

0374

200081

260201

630374

180086

240193

570374

First-M

ode+

XndashEcc

180086

380262

176

0374

200080

260159

630374

180088

230213

560374

First-M

odendash

XndashEcc

160070

320186

168

0374

200081

260200

630374

180088

230226

550374

Uniform

+X+Ecc

200083

400230

540177

220090

300208

710374

200101

270260

650114

Uniform

ndashX+Ecc

200090

410246

540111

220087

290220

710374

200115

270355

650248

Uniform

+XndashEcc

210094

390220

390096

220085

300177

710374

210105

270241

660310

Uniform

ndashXndashEcc

230080

300208

730164

220090

290231

710374

200101

270274

650324

First-M

ode+

Y+Ecc

170097

340229

150

0374

210065

270170

660374

170074

220143

510374

First-M

odendash

Y+Ecc

170083

380276

156

0374

21006

827

0188

660374

150074

200160

470374

First-M

ode+

YndashEcc

170083

370263

155

0374

21006

827

0186

660374

160071

200131

480374

First-M

odendash

YndashEcc

180094

350246

152

0374

210065

270173

660374

170070

220149

510374

Uniform

+Y+Ecc

210105

420276

155

0374

230076

310194

740374

220105

290221

700374

Uniform

ndashY+Ecc

190090

410259

690314

230076

310195

740374

200105

270241

650374

Uniform

+YndashEcc

220090

290254

690349

230074

310184

740374

210101

270191

660374

Uniform

ndashYndashEcc

220105

290271

690334

230074

310196

740374

220105

290274

700374


000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure A

250200150100500

XY

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A250200150100500

XY

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(d)






000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure BXY

250200150100500

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(d)





000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(a)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(b)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(c)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

300200150100500

(d)






000

010

020

030

040



XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)














120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra















39243

39578

39913

40248

40583

40918

41243

PIASTRA

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

456

0

8

16

24

32

79

80

81

83

85

86

87

89

91

92

93

95

97

98

99

101

103

104

105

1074560

4560

4560

4560

456

0

456

0

456

0

456

0

456

0

456

0

C

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

COLU

MN

CO

LUM

N

COLU

MN

CO

LUM

N

COLU

MN

1st floor

2nd floor

3rd floor

4th floor

5th floor


Ground floor

325

335

335

335

335

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

456

045

60

456

0

45604560

4560

456045604560 4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

4560

3560

356

0

35603560

3560

3560

3560

3560

3560

3560

3560

3560

3560

356

035

60

356

0

356

035

60

356

0

356

035

60

456

045

60

456

045

60

456

045

60

456

0

2 3 4 5 6 7

10 11 12 13 14 15

18 19 20 21 22 23

25 26 27 28 29 30 31

53

55

56

57

59

61

62

63

65

67

68

69

71

1

9

17

49

50

51

356

035

60

356

045

60

456

045

60

456

045

60

456

045

60

A B

4560

4560

4560

4560

4560

4560

4560

4560

4560

h = 21 cm

4560

4560

BEAMS 45 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 45 times 60

BEAMS 35 times 60

BEAMS 35 times 60

50times70

50times70

50times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

35times70

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60

BEAMS 35 times 60



120579119910 = 120601119910 1198711198813 + 00013 (1 + 15 ℎ119871119881

) + 013120601119910 119889119887119891119910radic119891119888 (1)







120579119906 = 1120574el 0016 sdot (03]) [max (001 1205961015840)

max (001 120596) 119891119888]0225

sdot (119871119881ℎ )035 25(120572120588119904119909(119891119910119908119891119888)) sdot (125100120588119889) (2)



IOPGA119888











correspo

ndingpeak

grou

ndacceleratio

n(IO


LimitState)

Capacityof

structureA

Capacityof

structureB

Capacity

ofstructureC

IODL

LSIO

DL

LSIO

DL

LS119889 119905lowast

PGAg

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

First-M

ode+

X+Ecc

160074

350223

174

0374

200081

260196

630374

180085

240218

560374

First-M

odendash

X+Ecc

180079

360241

175

0374

200081

260201

630374

180086

240193

570374

First-M

ode+

XndashEcc

180086

380262

176

0374

200080

260159

630374

180088

230213

560374

First-M

odendash

XndashEcc

160070

320186

168

0374

200081

260200

630374

180088

230226

550374

Uniform

+X+Ecc

200083

400230

540177

220090

300208

710374

200101

270260

650114

Uniform

ndashX+Ecc

200090

410246

540111

220087

290220

710374

200115

270355

650248

Uniform

+XndashEcc

210094

390220

390096

220085

300177

710374

210105

270241

660310

Uniform

ndashXndashEcc

230080

300208

730164

220090

290231

710374

200101

270274

650324

First-M

ode+

Y+Ecc

170097

340229

150

0374

210065

270170

660374

170074

220143

510374

First-M

odendash

Y+Ecc

170083

380276

156

0374

21006

827

0188

660374

150074

200160

470374

First-M

ode+

YndashEcc

170083

370263

155

0374

21006

827

0186

660374

160071

200131

480374

First-M

odendash

YndashEcc

180094

350246

152

0374

210065

270173

660374

170070

220149

510374

Uniform

+Y+Ecc

210105

420276

155

0374

230076

310194

740374

220105

290221

700374

Uniform

ndashY+Ecc

190090

410259

690314

230076

310195

740374

200105

270241

650374

Uniform

+YndashEcc

220090

290254

690349

230074

310184

740374

210101

270191

660374

Uniform

ndashYndashEcc

220105

290271

690334

230074

310196

740374

220105

290274

700374


000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure A

250200150100500

XY

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A250200150100500

XY

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(d)






000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure BXY

250200150100500

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(d)





000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(a)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(b)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(c)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

300200150100500

(d)






000

010

020

030

040



XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)














120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra











120579119906 = 1120574el 0016 sdot (03]) [max (001 1205961015840)

max (001 120596) 119891119888]0225

sdot (119871119881ℎ )035 25(120572120588119904119909(119891119910119908119891119888)) sdot (125100120588119889) (2)



IOPGA119888











correspo

ndingpeak

grou

ndacceleratio

n(IO


LimitState)

Capacityof

structureA

Capacityof

structureB

Capacity

ofstructureC

IODL

LSIO

DL

LSIO

DL

LS119889 119905lowast

PGAg

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

First-M

ode+

X+Ecc

160074

350223

174

0374

200081

260196

630374

180085

240218

560374

First-M

odendash

X+Ecc

180079

360241

175

0374

200081

260201

630374

180086

240193

570374

First-M

ode+

XndashEcc

180086

380262

176

0374

200080

260159

630374

180088

230213

560374

First-M

odendash

XndashEcc

160070

320186

168

0374

200081

260200

630374

180088

230226

550374

Uniform

+X+Ecc

200083

400230

540177

220090

300208

710374

200101

270260

650114

Uniform

ndashX+Ecc

200090

410246

540111

220087

290220

710374

200115

270355

650248

Uniform

+XndashEcc

210094

390220

390096

220085

300177

710374

210105

270241

660310

Uniform

ndashXndashEcc

230080

300208

730164

220090

290231

710374

200101

270274

650324

First-M

ode+

Y+Ecc

170097

340229

150

0374

210065

270170

660374

170074

220143

510374

First-M

odendash

Y+Ecc

170083

380276

156

0374

21006

827

0188

660374

150074

200160

470374

First-M

ode+

YndashEcc

170083

370263

155

0374

21006

827

0186

660374

160071

200131

480374

First-M

odendash

YndashEcc

180094

350246

152

0374

210065

270173

660374

170070

220149

510374

Uniform

+Y+Ecc

210105

420276

155

0374

230076

310194

740374

220105

290221

700374

Uniform

ndashY+Ecc

190090

410259

690314

230076

310195

740374

200105

270241

650374

Uniform

+YndashEcc

220090

290254

690349

230074

310184

740374

210101

270191

660374

Uniform

ndashYndashEcc

220105

290271

690334

230074

310196

740374

220105

290274

700374


000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure A

250200150100500

XY

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A250200150100500

XY

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(d)






000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure BXY

250200150100500

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(d)





000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(a)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(b)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(c)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

300200150100500

(d)






000

010

020

030

040



XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)














120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra











correspo

ndingpeak

grou

ndacceleratio

n(IO


LimitState)

Capacityof

structureA

Capacityof

structureB

Capacity

ofstructureC

IODL

LSIO

DL

LSIO

DL

LS119889 119905lowast

PGAg

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

119889 119905lowastPG

Ag

First-M

ode+

X+Ecc

160074

350223

174

0374

200081

260196

630374

180085

240218

560374

First-M

odendash

X+Ecc

180079

360241

175

0374

200081

260201

630374

180086

240193

570374

First-M

ode+

XndashEcc

180086

380262

176

0374

200080

260159

630374

180088

230213

560374

First-M

odendash

XndashEcc

160070

320186

168

0374

200081

260200

630374

180088

230226

550374

Uniform

+X+Ecc

200083

400230

540177

220090

300208

710374

200101

270260

650114

Uniform

ndashX+Ecc

200090

410246

540111

220087

290220

710374

200115

270355

650248

Uniform

+XndashEcc

210094

390220

390096

220085

300177

710374

210105

270241

660310

Uniform

ndashXndashEcc

230080

300208

730164

220090

290231

710374

200101

270274

650324

First-M

ode+

Y+Ecc

170097

340229

150

0374

210065

270170

660374

170074

220143

510374

First-M

odendash

Y+Ecc

170083

380276

156

0374

21006

827

0188

660374

150074

200160

470374

First-M

ode+

YndashEcc

170083

370263

155

0374

21006

827

0186

660374

160071

200131

480374

First-M

odendash

YndashEcc

180094

350246

152

0374

210065

270173

660374

170070

220149

510374

Uniform

+Y+Ecc

210105

420276

155

0374

230076

310194

740374

220105

290221

700374

Uniform

ndashY+Ecc

190090

410259

690314

230076

310195

740374

200105

270241

650374

Uniform

+YndashEcc

220090

290254

690349

230074

310184

740374

210101

270191

660374

Uniform

ndashYndashEcc

220105

290271

690334

230074

310196

740374

220105

290274

700374


000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure A

250200150100500

XY

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A250200150100500

XY

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(d)






000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure BXY

250200150100500

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(d)





000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(a)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(b)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(c)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

300200150100500

(d)






000

010

020

030

040



XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)














120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure A

250200150100500

XY

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A250200150100500

XY

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure A

250200150100500

XY

(d)






000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure BXY

250200150100500

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(d)





000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(a)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(b)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(c)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

300200150100500

(d)






000

010

020

030

040



XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)














120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










000

010

020

030Sp

ectr

al ac

cele

ratio

n (g

)




Structure BXY

250200150100500

(a)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(b)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(c)

000

010

020

030

Spec

tral

acce

lera

tion

(g)




Structure BXY

250200150100500

(d)





000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(a)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(b)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(c)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

300200150100500

(d)






000

010

020

030

040



XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)














120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(a)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(b)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

250200150100500

(c)

000

010

020

030

040

Spec

tral

acce

lera

tion

(g)




XY

Structure C

300200150100500

(d)






000

010

020

030

040



XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)














120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










000

010

020

030

040



XY

Structure A

000

010

020

030

040



Structure BXY

000

010

020

030

040



XYStructure C

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)

Dem

and

(PG

Ad

g)














120578 = radic 10(5 + 120585) ge 055 (3)


4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










4560

4560

103

107

105 99

98104

97

587

350

55 27

6727

27420

1562

101

92

91

83

81

8995

8793

86

85

4560

456

0

456

0

456

0

4560

456

0

4560

4560

456

0

456

0

456

0

4560

456

0

45604560

4560

456

0

45604560

5516

157 448 365 365 20390 365365390 365 365 365 310 320 365702080 390

4560 4560 4560 4560 4560 4560 4560 3560 3560 3560

41243

39243

39578

39913

40248

40583

40918

325

335

335

335

335

45604560 4560 4560 4560 4560 4560

45

60

1106

0

45

60

45

60

45

60

45

60

45

60

45

60

1106

0

45

60

45

60

45

60

356

0

1006

0

45

60

45

60

45

60

456045604560 4560 4560

4560 4560 45604560 4560 4560

4560 4560

67615549124 3567879

9 68625650

6963575117181920

1112 101314151680

356

0

356

0

65 715953

2526272829303132

212223

3560 35603560

4560 3560 35603560

3560 3560 3560

1006

0

456

0

456

0

456

0

456

0

1106

0

456

0

356

0

356

0

356

0356

0

422

350 1562

587

356

0

356

0

1006

0

5527

7025

25

456

0





1746

107

105

447

9515

035

058

716

30

104

103 97 91

98 92

99 93 87

86

85 268

267

272

32 31 30 29 28 27

5616390 365 365 365 365 365

25

53 59 65 71

6963572711820212223

15

7 6 5 3

14 13 12 11 10

269 55

56 62

61 67

390365203903653653653655516

39036539020390365365448157

68270

390 1265

101 95 89 83

587

350

447

9515

016

30

26

19

4 2



minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










minus300

minus200

minus100

0

100

200

300

Shea

r (kN

)

Displacement (mm)









119890119886119894 = plusmn005 119871 119894 (4)



000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










000

020

040

060

080

100Sp

ectr

al ac

cele

ratio

n (g

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(a)

00

100

200

300

400

Spec

tral

disp

lace

men

t (cm

)

Period (sec)

IODL

LSCP

400350300250200150100050000

TC

TA

TB

TIS

O

080T

ISO

(b)



119872119886119894 = 119890119886119894 sdot 119865119894 (5)

























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra























Period 3020 sec

Period 2265 sec

Period 0364 sec



Period 0342 sec

Period 0367 sec








Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










Step A Step B

Rebar M33

Drilling jig

Formwork

Anchor bolts

Concretejacketing

B B


jack

Step C Step D



Section view A-A

Lifting brackets


Hydraulic jack

Section view B-B


Hydraulicjack

B B

A A

Levellingmortar

Screw cap








5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra












5Φ16

Stirrups Φ810

Bent-down bars

5Φ16

5Φ16

4Φ16

4Φ164Φ16

4Φ16

4Φ16Bent-down bars

Stirrups Φ810

4Φ16

4Φ16

040

100

140



Stirrups Φ810

Perforation Φ24

145 200

040

100

140



stirrups Φ810









000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra











000204060810121416

Spec

tral

acce

lera

tion

(g)

Period (sec)400350300250200150100050000








minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra












minus030

minus020

minus010

000

010

020

030

Y-d

ispla

cem

ent (

m)

X (m)

40 503020100

e = 005

e = 000

e = minus005

Y

X









minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra













minus030

minus020

minus010

000

010

020

030

Y‐d

ispla

cem

ent (

m)


Y

X


(a)

minus400

minus300

minus200

minus100

0

100

200

300

400

Shea

r (kN

)


(b)



5 Conclusions




800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra










800600400200000

1400

1050

700

350

000

Y(m

)


A-B

Y

X

AB C

B-C(a)

800600400200000

1400

1050

700

350

000

Y(m

)


Y

X

A B C

A-BB-C

(b)





Notation























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra





























Competing Interests


Acknowledgments


References































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra
































































Volume 2014




Journal of











Journal of


Function Spaces






Algebra









Base Isolation for Seismic Retrofitting of a Multiple...

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Transcript of Base Isolation for Seismic Retrofitting of a Multiple...