Post on 17-Aug-2015
RETROFIT OF EXISTING TWO STOREY STRUCTURE WITH
THE FUTURE PERSPECTIVE OF ADDING AN ADDITIONAL
STOREY
George Georgiou Ch. (5583)
A Project Report
submitted in partial fulfillment of
the requirements for the degree of
BSc Civil Engineering
Supervisor: Dr. Petros Christou
Department of Civil Engineering
Frederick University
December 2013
DECEMBER 2013
Da Vinci Vitruve Luc Viatour
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Acknowledgment
This project would not have been possible without the support of many people. First, I would
like to thank my supervisor, Dr. Petros Christou for his valuable guidance and continuous
advice and support. I would also like to thank my family, for their support, patience and
understanding in the course of this three year study; special thanks to my wife Elena, my
baby-girl Mary- Angeliki, my mother-in-law Mary, my colleague Mr.George Georgiou and my
boss Mr. Christos Koupparis and his company C. KOUPPARIS AND ASSOCIATES. All of the
above have been providing me with the requisite moral support to continue and complete this
course. Furthermore, I would like to thank my friend and classmate Mr. Sokratis Lambrou for
his guidance in connection with the application of the software STEREOSTATIKA .
Finally, I would like to thank the committee responsible for this Project namely: Dr.
Petros Christou, Dr. Demetris Nicolaides and Dr. Michael Antonis.
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Table of Contents
Chapter 1 .................................................................................................................................. 10
1.1 Introduction ...........................................................................................................................10
Chapter 2 .................................................................................................................................. 12
2.1 Description of the existing building .....................................................................................12
Chapter 3 .................................................................................................................................. 16
3.1 Literature Review .................................................................................................................16
3.1.1. Retrofitting of a medieval bell tower ..................................................................... 17
3.1.2. Underwater pre-stressed piles repair ................................................................... 19
3.1.3. Retrofitting of hollow bridge piers ......................................................................... 20
3.1.4. Strengthening of R.C. beam – column joints ........................................................ 21
3.1.5. Concrete confined with FRP tubes ....................................................................... 23
3.1.6. Heritage university building .................................................................................. 23
3.1.7. Arresting leakage in Muran dam .......................................................................... 24
3.1.8. Reinforced Concrete jacketing ............................................................................. 24
3.1.9. Examples of repairing structural elements with the use of jacketing: .................... 29
3.1.10. Decision of retrofit method ............................................................................... 37
Chapter 4 .................................................................................................................................. 38
4.1 Methodology .........................................................................................................................38
Chapter 5 .................................................................................................................................. 43
5.1 Analysis and Results ..........................................................................................................43
5.1.1. Data collection ..................................................................................................... 43
5.1.2. Procedure - Evaluation of Data ............................................................................ 44
5.1.3. Output - Results ................................................................................................... 46
5.1.4. Final Results: ....................................................................................................... 51
Chapter 6 .................................................................................................................................. 52
6.1 Discussion ............................................................................................................................52
6.1.1. General Conclusions .......................................................................................... 53
Chapter 7 .................................................................................................................................. 55
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References .......................................................................................................................................55
APPENDIX - A .......................................................................................................................... 56
Solutions for the rest of Columns ...................................................................................................56
For 1C4:............................................................................................................................. 56
For 1C5:............................................................................................................................. 57
For 1C6:............................................................................................................................. 58
For 1C7:............................................................................................................................. 59
For 1C10:........................................................................................................................... 60
For 1C11:........................................................................................................................... 61
For 1C12:........................................................................................................................... 62
For 1C21:........................................................................................................................... 63
For 1C25:........................................................................................................................... 64
For 1C27:........................................................................................................................... 65
For 1C28:........................................................................................................................... 66
For 1C29:........................................................................................................................... 67
APPENDIX - B .......................................................................................................................... 69
Tutorial .............................................................................................................................................69
Calculation procedure for Case 1: ...................................................................................... 69
Calculation procedure for Case 2: ...................................................................................... 77
APPENDIX - C .......................................................................................................................... 78
EXCEL FORMULAE – THE FIVE STEP ANALYSIS ...................................................................78
Step 1 ................................................................................................................................ 79
Step 2 ................................................................................................................................ 79
Step 3 ................................................................................................................................ 79
Step 4 ................................................................................................................................ 79
Step 5 ................................................................................................................................ 80
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Table of Figures
Figure 2-1 The two storey building during renovation of Ground floor in 2010 ....................... 13
Figure 2-2 Plan of Foundation ............................................................................................... 13
Figure 2-3 Plan of Ground Floor............................................................................................ 14
Figure 2-4 Plan of First Floor ................................................................................................ 14
Figure 2-5 3D/View North-East side of the RC Building ........................................................ 15
Figure 3-1 - Cross section of bell tower ................................................................................. 19
Figure 3-2 - Comparision of Push over curves of retrofitted and Un-retrofittes structures ...... 20
Figure 3-3 - Typical effect of confinement of column ............................................................. 22
Figure 3-4-types of column jacket ......................................................................................... 26
Figure 3-5-column jacket....................................................................................................... 27
Figure 3-6-types of column jacket ......................................................................................... 28
Figure 3-7-column jacket (section) ........................................................................................ 28
Figure 5-1-Formwork of First Floor with the problematic columns ......................................... 43
Figure 5-2 Brief report of column in STEREOSTATIKA ......................................................... 44
Figure 5-3 Design with the use of Excel ................................................................................ 44
Figure 5-4- new section of 1C3 ............................................................................................. 47
Figure 5-5-Showing the new section of 1C3 (plan) ................................................................ 47
Figure 5-6-Calculation and Design process for the proposed section .................................... 48
Figure 5-7-Element problem check from STEREOSTATIKA ................................................. 48
Figure 5-8-Design of jacket-section for 1C3 .......................................................................... 51
Figure 6-1-Results of Element problem check ....................................................................... 52
Figure A 1-Design of jacket-section for 1C4 .......................................................................... 56
Figure A 2-Design of jacket-section for 1C5 .......................................................................... 57
Figure A 3-Design of jacket-section for 1C6 .......................................................................... 58
Figure A 4-Design of jacket-section for 1C7 .......................................................................... 59
Figure A 5-Design of jacket-section for 1C10 ........................................................................ 60
Figure A 6-Design of jacket-section for 1C11 ........................................................................ 61
Figure A 7-Design of jacket-section for 1C12 ........................................................................ 62
Figure A 8-Design of jacket-section for 1C21 ........................................................................ 63
Figure A 9-Design of jacket-section for 1C25 ........................................................................ 64
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Figure A 10-Design of jacket-section for 1C27 ...................................................................... 65
Figure A 11-Design of jacket-section for 1C28 ...................................................................... 66
Figure A 12-Design of jacket-section for 1C29 ...................................................................... 67
Figure A 13-Plan view of first floor ........................................................................................ 68
Figure A 14-3D view with the final sections-first floor ............................................................ 68
Figure B 1-RC Building regulation ......................................................................................... 69
Figure B 2-Specify Concrete and his properties accordance to EC 2 .................................... 70
Figure B 3-Rebar Steel and its properties in accordance to EC 3 .......................................... 70
Figure B 4-Stirrups Steel and his properties accordance to EC 3 .......................................... 71
Figure B 5-Steel section and his properties accordance to EC 3 ........................................... 71
Figure B 6-Ground type and properties ................................................................................. 72
Figure B 7-Earthquake risk zone accordance to EC 8 ........................................................... 72
Figure B 8-Stiffness Parameters ........................................................................................... 73
Figure B 9-Space Frame Parameters.................................................................................... 73
Figure B 10-Specify Units ..................................................................................................... 74
Figure B 11-Design Assumptions .......................................................................................... 74
Figure B 12-3D model of exist structure showing the element checks with colors ................. 76
Figure B 13-3D model of design structure showing the element checks with colors .............. 77
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List of tables
Table 4-1 Plot for ratio d’/h=0.05 ........................................................................................... 40
Table 4-2 Plot for ratio d’/h=0.10 ........................................................................................... 40
Table 4-3 Plot for ratio d’/h=0.15 ........................................................................................... 41
Table 4-4 Plot for ratio d’/h=0.20 ........................................................................................... 41
Table 4-5 Sectional areas of groups of bars (mm2)............................................................... 42
Table 4-6 Perimeter and weight of bars ................................................................................ 42
Table 4-7 Sectional areas per meter width for various bar spacings (mm2) .......................... 42
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List of Abbreviations
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Chapter 11.1 Introduction
The final year project is undertaken by every student in his final year of study, in order to
provide him with the opportunity to work on a subject which poses interest to him.
Having considered a number of different possible projects to be examined and after
having discussed the various alternatives with Professor Dr. Christou Petros, we have jointly
decided that my final year project should focus on the following matters:
the year project should be associated with the immediate present and future of the science of
Civil Engineering in the Republic of Cyprus. It is well known that Cyprus is an island and
therefore there is a limited ability to construct new buildings because the land is small. It can
be supported that it is of an immense importance to focus on alternative ways of
constructions. The alternative way which will be analyzed thoroughly in this dissertation is the
need to undertake additions to existing reinforced concrete buildings either by adding
additional floors or by expanding the said building. In order to undertake the aforementioned
actions, the static adequacy and antiseismic study of the reinforced concrete building need to
be taken into account so as to determine the type of construction which may be used and the
type of reinforcements which will be required to the various elements of construction (beams,
columns).
The main objective of this Project will be the evaluation of the capacity of an existing
RC building, the subsequent addition of an extra storey and retrofitting of structural elements
where is necessary. The choice of that is because this is the majority in Cyprus.
As part of the methodology plan to be followed the following steps will be taken:
a simulation of the current RC building will be undertaken;
the structure will be analyzed and designed via the use of a commercial software
namely STEREOSTATICA;
subject to the structural analysis to be produced the next step will be to determine the
appropriate reinforcement to be carried out so that the additional floor is added with
safety;
the addition will have to be in line with the relevant Cypriot Legislative Framework and
with the Eurocode 2, Eurocode 8; and
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subject to all of the aforementioned actions once the existing elements are evaluated
then new elements will be designed and situated accordingly.
The benefit of this Project is that in view of the impact of the economic crisis the option
of adding floors to existing buildings would in the immediate future be the preferred option
since it will be less costly than acquiring land plots and undertaking initial construction.
Therefore, via this Project it will be proved that adding floors is a viable solution and such a
solution can be in line with the Laws and Regulations of the Republic of Cyprus.
The purpose of this dissertation will be to evaluate the adequacy of the existing
building, to provide a viable solution in connection with its reinforcement (in the instance in
which the existing building is deemed inadequate) so that the addition of the extra storey is
deemed feasible and subsequently the entire building is in line and in accordance with the
European Code and especially with its provisions in connection with the antiseismic design.
This dissertation will be divided into seven chapters and three appendixes. A
summary and a short articulation regarding each of the seven chapters and the three
appendixes are provided herein below:
Chapter 1: Introduction;
Chapter 2: A short description of the existing RC building;
Chapter 3: Literature Review;
Chapter 4: The Methodology;
Chapter 5: An analysis of the results reached will be undertaken;
Chapter 6: The general conclusions reached subject to the aforementioned study will be
presented; there will be a short analysis of the advantages and disadvantages
associated with the use of STEREOSTATIKA software and other conclusions reached;
Chapter 7: A detailed list of the references relied for the purposes of this dissertation;
Appendix-A: Solutions for the rest of Columns;
Appendix-B: Tutorial of the Calculation procedure in STEREOSTATIKA;
Appendix-C: Preview of the Excel Formulae
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Chapter 2
2.1 Description of the existing building
The actual building which will be analyzed for the purposes of my final year project is an
existing two floor residential building located in Strovolos, Nicosia and was constructed in two
stages.
The ground floor was built in 1967 and the first floor was subsequently constructed
and added in 1980.
The dimensions of the ground and first floor respectively as they appear on the plan are the
following: 16900x13400 (figure 2.3) and the 16900 x11200 (figure 2.4). At the infrastructure
of the building we encounter the method of foundation beams and at the superstructure of the
building on the ground floor the majority of the sections of the columns are 350x400 and the
beams are 200x450 and in connection with the first floor the majority of the sections of the
columns are 200x300 and the beams are 200x450 and finally the depth of Slabs are 15cm.
The basic structural materials that were used were the following: Concrete C20 and Steel
S400.
In 2010 the ground-floor was renovated with the aim to extend its coverage area
(figure 2.1). Due to this extension, the majority of the existing columns had to be reinforced
with cementitious mixture Emaco T545 so as to improve wear resistance and also the section
of the columns was increased to 350x400.
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Figure 0-1 The two storey building during renovation of Ground floor in 2010
The plans of the existing building are shown below:
Figure 0-2 Plan of Foundation
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Figure 0-3 Plan of Ground Floor
Figure 0-4 Plan of First Floor
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3D/View of the existing RC Building in Figure 2.5
Figure 0-5 3D/View North-East side of the RC Building
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Chapter 33.1 Literature Review
Undoubtedly nowadays there is a wide spectrum of civil engineering structures that are being
constructed.
For example, buildings, bridges, dams, underground storage structures, overhead
storage structures, high-rise structures, launch pads, airport terminals, stadia, shopping malls,
Cineplex’s, swimming pools, etc., are some of the structures which have been built in order
to accommodate different purposes and to carry out different activities. These structures are
constructed with the use of materials such as masonry, concrete, steel and aluminum. The
material to be used is subject to the following two considerations: a) the design requirement
and b) the economic aspect.
These structures are subjected to different geophysical and man-made loads during
their service life. When the magnitude of these loads exceed the capacity or strength of these
structures, then they are likely to sustain damages. Taking into account that a) building a
new structure to replace the existing structure is an expensive option and b) that during the
construction of the new structure there will be an interruption in the use of the structure with
subsequent financial losses to the owners, as well as other economic and environmental
factors, the decision to repair and reinforce the existing "damaged" structure becomes more
imminent. Sometimes the strength of a structure is reduced because of the use of
substandard materials in its construction or due to the application of additional load because
there is a change in its functioning or due to seismic forces for which were not taken into
account in the original design of the structure.
The aforementioned situations warrant strengthening or up-gradation of the structure
so as to enable it to carry the enhanced loading. A variety of structural up-gradation and
retrofitting techniques have evolved and applied in practice over the years subject to the
potential structure in place. Some methods of seismic up-gradation such as the addition of
new structural frames or shear walls have been proven to be impractical because they have
been either too costly or their use has been limited only to certain types of structures. Other
strengthening methods such as grout injection, insertion of reinforcing steel, pre-stressing,
jacketing, and different surface treatments have been summarized by Hamid et al. (1994).
Each of these methods involves the use of skilled labour and disrupts the normal functions of
the building.
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These well-known techniques may sometimes be inadequate if the intention is to preserve
architectural heritage with added historical value. FRP composites are now increasingly used
in the construction industry and offer considerable potential for greater use in buildings,
including large primary structures. In recent years more complex applications have been
developed to satisfy the desire for more dramatic features in building design. FRP composites
have numerous potential advantages in building construction including the following: a) offsite
fabrication and modular construction reduced mass, b) superior durability c) ability to mould
complex forms, d) special surface finishes and effects, and e) improved thermal insulation
and f) lack of cold bridging (Kendall, 2007).
As a repair material Polymeric Matrix or FRP presents also significant advantages in
comparison to more traditional confinement techniques such as: a) the cross sectional
dimensions of the column do not increase and this permits compliance with architectural
restraints; b) the mass of the column does not increase, which means that the seismic
behavior of the building remains unchanged (Minicelli & Tegola, 2007); c) the low weight of
FRP materials implies that the installation procedure is faster, easier and less dangerous for
the operator than implementing traditional confining techniques. Modern techniques of
confinement consist of wrapping sheets or laminates with FRP .
During the last decade these techniques were introduced in engineering practice as
innovative confinements techniques and as an alternative to wood or steel ties which were
applied in the past. Therefore the use of FRP laminates for retrofitting and strengthening is a
valid alternative technique because of its small thickness, high strength-to- weight ratio and
ease of application.
Having reviewed the available literature on this matter, this paper presents a number
of case studies regarding the application of FRP to strengthen and retrofit masonry in un-
reinforced and reinforced structures; concrete structures; pre-stressed concrete structures;
masonry arches; underwater piles; bridge piers; monumental structures, etc.
3.1.1. Retrofitting of a medieval bell towerRetrofitting of existing structures so as to enable them to resist seismic actions which were
originally not accounted in the design is very common in structural engineering. Seismic
retrofitting of monument structure demands compliance with restrictive constraints related to
the preservation of original artistic and structural features. Any conceived intervention must
aim to attain structural performance whilst the appearance and structural mechanism of the
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original monument be respected and the intervention be as less invasive as possible. The
intervention on the bell tower of Santa Lucias Church in Serra San Quirico, Ancona, Italy is
an example of the application of composite materials for the seismic retrofit of historic
monuments where traditional retrofit strategies are not suitable. Cosenzo and Iervolino (2007)
have presented a case study which focused on the retrofitting of the medieval bell tower of
Santa Lucias Church in Serra San Quirico using the FRP.
The bell tower of Santa Lucias Church is a multilayered masonry structure which was
built in the XV century and was affected by the Umbria-Marche earthquake that took place in
1997. It is located at the centre of the little tower of Serra San Quirico, a medieval suburb
near Ancona and is surrounded by many residential constructions of the same age.
It is a calcareous masonry building; about 30 m in height and 1,200 m in width with a
rectangular plan view (Fig. 3.1). By reason of the fact that similar structures in the same area
sustained damage and those structures failed to resist to seismic loads, the local
Architectural Heritage Supervision Office expressed its desire to improve the seismic capacity
of the tower. Initially, in order to fulfill the scope of retrofitting an intervention based on steel
reticular system anchored to the inner side of the tower was proposed. The Architectural
Heritage Authority recognized that this intervention violates the above described principles
and, therefore, rejected it. Subsequently an FRP intervention was proposed, designed,
approved and installed.
The design also included a finite element simulation and a site structural assessment. The
effectiveness of the intervention was evaluated by performing nonlinear static analysis, i.e.,
push over analysis, both on retrofitted and original structures and by comparing the results.
Pushover curves for the retrofitted and un-retrofitted structures are provided in Fig 3.2.
The FRP intervention enhanced the seismic capacity of the bell tower structure and is
fully provisional as it may be removed by heating the FRP with a hot air jet.
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3.1.2. Underwater pre-stressed piles repairMullians et al. (2005) have provided a field demonstration study to evaluate the application of
FRP in connection with the underwater repair of corroding prestressed piles. A total of four
full sized 350 mm × 350 mm square pre-stressed piles were wrapped, two with carbon and
two with glass. Two of these wrapped piles, i.e., one carbon and one glass, were
instrumented to allow evaluation of their post wrap performance. Two other unwrapped piles
served as control. Instrumentation allowed determination of the corrosion potential over the
unwrapped surface and the corrosion rate for the wrapped piles.
Figure 0-1 - Cross section of bell tower
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Figure 0-2 - Comparision of Push over curves of retrofitted and Un-retrofittes structures
The study proved that the underwater wrapping in a visible system. As with most FRP
retrofits, surface preparation is of paramount importance. In this case, surface preparation
required equipment capable of operating underwater so as to grind sharp corners.
Although initial field tests on the witness panels indicated that the bond between the
wet concrete and the FRP was relatively poor, laboratory tests indicated that the bond was
adequate to restore the full undamaged capacity. Corrosion rate measurements illustrated
that the performance of the wrapped piles is consistently better than that of the unwrapped
controls. The underwater wrap used a unique water activated urethane resin system that
eliminated the need for cofferdam construction. The preliminary findings were quite
encouraging and suggested that underwater wrapping without cofferdam construction may
provide a cost-effective solution for pile repair.
3.1.3. Retrofitting of hollow bridge piersIn order to maximize efficiency in terms of the strength-to-mass and stiffness-to-mass ratios
and to reduce the mass contribution of the pier-to seismic response, it has been common
engineering practice to use hollow sections for bridge piers, particularly for tall piers. Hollow
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bridge piers are currently being used in high speed rail and highway projects in Taiwan.
Recent earthquakes such as the Northridge earthquake of 1994, the Kobe earthquake of
1995, and the Taiwan earthquake of 1999, have respectively demonstrated the vulnerability
of older reinforced concrete piers to seismic deformation demands and shear strength. Yeh
and Mo (2005), have presented the results of their research on hallow piers retrofitted with
carbon fiber reinforced polymer (CFRP) sheets.
In their research the authors have tested circular and rectangular hallow bridge piers
retrofitted by CFRP sheets under a constant axial load and a cyclic reversed horizontal load
to study their seismic behavior, including flexural ductility, dissipated energy and shear
capacity. An analytical model was also developed to predict the moment curvature
relationship of sections and the lateral load displacement relationship of piers. The test
results were also compared with the proposed analytical model. It was found that the ductility
factor of the tested piers ranged from 3.3 to 5.5 and that the proposed analytical model could
predict the lateral load displacement relationship of such piers with reasonable accuracy. All
in all, it was concluded that CFRP sheets can effectively improve the ductility factor and the
shear capacity of hollow bridge piers.
3.1.4. Strengthening of R.C. beam – column jointsRecent earthquakes that have occurred across the world have illustrated the vulnerability of
existing reinforced concrete (RC) beam-column joints to seismic loading. Strengthening of
R.C. joints is a challenging task that poses major practical difficulties.
A variety of techniques applicable to concrete elements have also been applied to
joints with the most common ones being the construction of RC or steel jackets. However,
these techniques have an inherent limitation which takes the form of intensive labour and
artful detailing. In the case of concrete solutions there is a great possibility o that the
dimensions and weights of the elements are to increase.
Recently, a new technique based on the FRP for structural elements has evolved.
This technique involves the use of FRP as externally bonded reinforcement (EBR) in critical
regions of RC elements. FRP materials which are available today in the form of strips or in
situ resin impregnated sheets, are used to strengthen a variety of RC elements, including
beams, slabs, columns, and shear walls, to enhance the flexural, shear, and axial capacity of
such elements.
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The results of a comprehensive experimental program presented by Antonopoulos
and Triantafillou (2003) focused in providing a basic understanding of the behavior of shear-
critical RC joints strengthened with FRP under simulated seismic load. The role of various
parameters such as area fraction of FRP; distribution of FRP between the beam and the
columns; axial load of column; steel reinforcement in internal joint; initial damage; carbon
versus glass fibres; sheet versus strips; and the effect of transverse beams, on the effective
FRP has been examined through 2/3 scale testing of 18 exterior RC joints.
In the aforementioned study the performance of the tests demonstrated that externally
bonded FRP reinforcement is a viable solution towards enhancing the strength, energy
dissipation, and stiffness characteristics of poorly detailed RC.
Figure 0-3 - Typical effect of confinement of column
Joints in shear that are subjected to simulated seismic loads. Relatively low fraction of
FRP area enhanced both in the peak lateral load capacity and the cumulative dissipated
energy up to about 70 to 80 percent. The increase in stiffness varied and the imposed
displacement level reached values in the order of 100 percent. The results demonstrated the
important role of mechanical anchorages in limiting premature de-bonding.
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3.1.5. Concrete confined with FRP tubesAxial load on concrete results in the lateral expansion of the concrete. In an encased
concrete column, this lateral expansion is resisted by the hoop action of the shell that
surrounds the concrete. Such confinement changes the stress-strain behavior of concrete
and also increases its compressive strength as shown in (Fig. 3.4), which depicts the typical
stress-strain relationship of un-confined concrete, confined by FRP tube and by a steel tube
respectively.
The advantage of improved performance of concrete encased in steel tubes has been well
recognized and is used in structural applications (Choi and Xiao, 2010). However, the use of
FRP tubes to encase concrete columns instead of steel is a more recent development that
offers certain advantages, such as the elimination of corrosion of the confining tube. FRP
tubes are also light-weight and easy to handle. They act as an ideal formwork that eventually
remains in place as permanent part of the structure.
The confining pressure of an FRP shell subjects the core concrete to a tri-axial state
of stress. Concrete itself prevents the shell from buckling inward. The shell protects the
concrete surface from physical damage and environmental effects such as carbonation and
chloride penetration. The shell acts as a uniform longitudinal reinforcement located at the
most advantageous position so as to resist moments. Therefore, concrete confined with FRP
is currently considered as a technically attractive system for piles, highway overhead signs,
and other compression members that can be subjected to moments. Bacque et al., (2003)
developed analytical models in order to predict the stress-strain curves for concrete confined
with FRP. Having used the analytical models, the predicted stress-strain curves for confined
concrete were compared with those that resulted by reason of the tests on concrete
specimens confined with FRP. The agreement was found to be good.
The proposed model was also able to predict that concrete confined with a GFRP
exhibits better ductility as compared with concrete confined with CFRP. The above is a very
well-known and expected behavior of concrete confined with GFRP.
3.1.6. Heritage university buildingNanda and Sahoo (2010) have presented the factors that were influencing the damages and
the repairing methodology to be adopted in connection with the restoration work of the
heritage Ravens Haw University situated on Orissa and originally constructed in 1868. Fine
cracks in the walls were sealed with epoxy putty instead of wall stitching. Four grouting port
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holes were provided along the cracks. Nozzles were fixed and grouting was performed with
water-insensitive high-bond strength epoxy of density 1.1 kg/L, compressive strength 75 MPa,
tensile strength 34 MPa, and bond strength 3.5 MPa. Styrene Butadiene rubber emulsion
based latex modified concrete was used to apply a ferrocement treatment so as to repair the
leaking roof of the building.
3.1.7. Arresting leakage in Muran damThe step by step approach in "arresting" water leakage that was taking place in the inspection
gallery of Muran Dam via the use of Polyurethane (PU) injection system was described by
Mishra (2010). The Muran Dam is located on Muran River in Khatiguda in Orissa. The walls
of the inspection gallery were made out of concrete and were constructed in an old pattern.
Keeping in mind the age, the thickness, the strength and other physical conditions, a PU
injection system was considered for arresting leakages. Following the elapse of a
considerable time as of the repair, the engineer in-charge confirmed that the system was
completely successful as the affected area was intact even after the rise of the water levels in
the upstream side.
3.1.8. Reinforced Concrete jacketingIf possible, a four sided jacket should be used. For its design, a monolithic behavior of the
composite columns can be assumed. The minimum width of the jacket should be 10 cm for
concrete cast in place and 4 cm for concrete. Two main types of column jacketing have been
used, as shown in figure 3.4. The type illustrated in figure 3.4a is used to increase the shear
capacity of the column and thus it aims to accomplish a strong column- weak beam design.
The second type, where the longitudinal steel of the jacket is made continuous through the
slab system and is carefully anchored to the foundation, was widely used in Cyprus,
simultaneously with the jacketing of the beams, (reference is made in figure 3.4b). Because
of the existence of the beams, usually the longitudinal reinforcement was concentrated in the
column comers, where bar bundles were used. It is recommended that no more than 3 bars
are bundled together. Windows are usually bored through the slab to allow the steel to go
through, as well as to enable the concrete casting process.
Figures 3.5b and 3.5c show options for the detailing of the longitudinal reinforcement
to avoid the excessive use of bundles.
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The percentage of steel with respect to the jacket area should be limited in the range
between 0.015 to 0.04, and at least a #5 bar should be used at every corner for a four
sided jacket.
Shear reinforcement should be designed and spaced subject to earthquake design
practice, although it is suggested that the minimum bar diameter used for ties is no less than
9.5 mm (#3 bar) or 1/3 the diameter of the biggest longitudinal bar. The ties should have 135°
hooks with 10 bar diameters of anchorage. In Cyprus, due to
the difficulty of manufacturing 135° hooks on the field, 90°
hooks were provided to the ties of several structures. To avoid
this problem, ties made of multiple pieces, as shown in figure
2.5, can be used.
Another aspect that has been observed in Cyprus is
the significant change encountered in connection with the
shear span/depth (a/d) ratio of existing columns once they are
jacketed. In several jacketing schemes used in framed
buildings in Cyprus, where the typical story height is 3 m, columns’ a/d ratio (computed
assuming an inflection point exists along the height of the member) would be typically
reduced to values less than two and in some cases to ratios less than 1.5. A column with this
a/d ratio is very likely to change from a flexural behavior to a shear dominated one. This type
of column, which is subjected to a double curvature deformation, would behave very similar to
a deep beam coupling two shear walls: shearing forces and consequent diagonal cracking is
likely to cause radical redistribution of tensile forces along the flexural reinforcement. Due to
the effects of diagonal tension, members with a/d ratios less than about two have tensile
stresses acting along the entire length of their longitudinal reinforcement, even at locations
where conventional flexural theory would predict compressive-stresses. This was observed
by Paulay (1971) in deep beams, and by Bett, et.al. (1985) in jacketed short columns.
For a column with continuous longitudinal steel (figure 2.6b) the conventional design
guidelines for flexural concrete elements could be potentially invalidated, because both
tension and compression steel could be in tension at a critical section. Thus, the interaction of
flexure and shear in this type of elements causes a reduction in the flexural capacity. The
inelastic behavior of such members is likely to be strongly affected by shear effects and thus
their energy dissipation capacity will be diminished.
The lack of space in the structure makes it very difficult to provide midface
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longitudinal bars, as shown in figure 3.7, or supplementary crossties to confine the concrete
on this portion of the column. Bett, etal.(1985) concluded that although this supplementary
longitudinal and transverse reinforcement did not have a significant effect on the monotonic
stiffness and strength of jacketed short columns for small drifts, they were beneficial in
controlling the strength and stiffness degradation under repeated cycles of reversed
displacements exceeding 2% drift, where the column worked within its inelastic range of
behavior.
Although it cannot be asserted that a jacketed column would have a double curvature
deformation during an earthquake, the above discussion has shown that its design is not an
easy task and its behavior is uncertain. One aspect that should be outlined is that deep
concrete elements are not likely to behave adequately in the inelastic range when they are
not detailed properly (this is the case for the majority of jacketed columns in real structures).
This points to the fact that when a framed structure is jacketed, energy dissipation should be
concentrated at the beams, while the columns should remain elastic or have limited inelastic
demands. Even in the instances where the a/d ratio is not reduced to values observed in
Mexican practice, the impossibility to provide adequate detailing for inelastic behavior of the
jacketed columns leads to a strong column-weak beam design.
Figure 0-4-types of column jacket
(a) (b) (c)
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Figure 0-5-column jacket
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Figure 0-6-types of column jacket
1. additional reinforcement2. existing reinforcement3. additional ties4. existing rc concrete5. additional rc concrete6. dowels
1
3
4
6
2
5
Figure 0-7-column jacket (section)
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3.1.9. Examples of repairing structural elements with the use ofjacketing:
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The use of FRP as a strengthening and retrofitting material has several advantages over the
use conventional materials in such a way. Its thickness is small and hence its application
does not add weight to existing structures. It helps to preserve the cultural heritage of
monumental structures. It is not corrodible. In the case study of the bell tower of Santa
Lucias Church in Serra San Quirico, Ancona, Italy it was shown that the FRP intervention
enhanced its seismic capacity and such a solution was acceptable to the local Architectural
Heritage Authorities.
Underwater FRP wrappings without cofferdam construction could provide a cost
effective solution for pile repair. CFRP sheets can effectively improve the ductility factor and
the shear capacity of hollow bridge piers. It was found that the ductility factor of tested piers
ranged from 3.3 to 5.5. It has been demonstrated via the application of experiments that
externally bonded FRP reinforcement is a viable solution towards enhancing the strength,
energy absorption and stiffness characteristics of poorly detailed RC joints in shear.
The use of FRP tubes to encase concrete columns instead of steel is a more recent
development that offers certain advantages, such as the elimination of corrosion of the
confining tube. FRP tubes are also light-weighted and easy to handle. The heritage university
building was restored by repairing the fine cracks of the walls by epoxy injection and via the
use of ferrocement treatment using latex modified concrete to repair the leaking roof. The
leakage in the walls of the inspection gallery in a dam was arrested by Polyurethane (PU)
injection system.
3.1.10. Decision of retrofit methodHaving reviewed the two types of reinforcement available and namely on the one hand the
FRP reinforcement and on the other hand the reinforced concrete jacketing, I have reached
to the prima facie conclusion that the method of FRP should not be opted for subject to the
following considerations:
the designing process would have been extremely difficult;
there is no sufficient background and expertise in the use of this method in Cyprus; and
the cost would have been detrimental.
Therefore I have decided to apply the method of reinforced concrete jacketing for the
purposes of this dissertation subject to the following two principal considerations:
it’s been widely and customarily used; and
there is sufficient background knowledge and expertise in its use in similar occasions.
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Chapter 44.1 Methodology
The steps that I undertook can be enumerated and listed as follows:
1.1.1. Initially I found the drawings relating to the existing RC building;
1.1.2. I went on location and I compared the building in connection to the drawings I had in
my possession;
1.1.3. The next step was to design the model of the exististing RC building with the
assistance of the commercial software STEREOSTATIKA;
1.1.4. Following, I added an additional floor and I did run the software with different load
combinations of Earthquake in accordance to Eurocode 8. Different results were
produced and I made use of the results (N ,M ) relating the worst load
combination for each problematic column;
1.1.5. Having in mind the following factors:
the existing condition of the building and
that the method of column reinforcement would be the jacketing method it was
evident that part of the capacity of the existing column would have been used for
the calculations for the design of the new reinforcement section.
As a result of all of the above, the following decisions were taken:
Regarding the existing section:
o safety factor 10% for the strength Grade of the reinforced concrete
( 20 18)
o safety factor 10% for the strength Grade of steel ( 400 360)
o safety factor 30% for the capacity of steel reinforcement
Regarding the proposed section:
o safety factor 10% for the strength Grade of reinforced concrete
( 30 27)
o safety factor 10% for the strength Grade of steel ( 500 450)
o New dimensions of the section from 200 300 to 400 300
1.1.6. The next step concerned the use of Excel (refer to APPENDIX-C). In the said
software I applied the results of STEREOSTATIKA (N ,M - see figure 5.2) in
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combination with the aforementioned parameters and I made use of the end results
regarding the proposed steel reinforcement ( ) of the new section.
1.1.7. I went back to STEREOSTATIKA, and I applied the new data (A , handb) and I
rerun it and I observed that the problematic was no longer problematic and the said
column no longer encountered a capacity problem. Therefore, subject to the above I
proceeded with producing the final design of the proposed section.
1.1.8. The final step concerned the repetition of the aforementioned procedure for all the
problematic columns (refer to APPENDIX- A)
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Tables and charts that I used for the calculations:
Table 0-1 Plot for ratio d’/h=0.05
Table 0-2 Plot for ratio d’/h=0.10
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Table 0-3 Plot for ratio d’/h=0.15
Table 0-4 Plot for ratio d’/h=0.20
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Table 0-5 Sectional areas of groups of bars (mm2)
Table 0-6 Perimeter and weight of bars
Table 0-7 Sectional areas per meter width for various bar spacings (mm2)
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Chapter 55.1 Analysis and Results
As it was expected, in the course of the antiseismic analysis, the following columns in the first
floor had a capacity problem (figure 4.1):1C3, 1C4, 1C5, 1C6, 1C7, 1C10, 1C11, 1C12, 1C21, 1C25, 1C27, 1C28, 1C29
Figure 0-1-Formwork of First Floor with the problematic columns
Herein below, there will be an analysis of the procedure followed in connection with the
design and the reinforcement method applied in connection with column 1C3. The remaining
solutions (design and reinforcement) of all other problematic columns will be presented in
Appendix A of this dissertation.
5.1.1. Data collectionInitially by adding the extra storey, I will make use of the following elements N ,M
which will result in STEREOSTATICA (figure 4.2), by way of the least beneficial load
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combination of each column. It has to be noted that STEREOSTATIKA included all necessary
parameters in accordance with Eurocodes' 2, 3 and 8.
For column 1C3:
Figure 0-2 Brief report of column in STEREOSTATIKA
5.1.2. Procedure - Evaluation of DataThe data were evaluated manually via the use of Excel (figure 5.3) with a factor of safety in
the region of 10% in connection with the existing grade of RC concrete and grade of steel.
The reasoning behind this approach was due to the fact that I was unaware of the existing
condition of the column. In addition, I will also cross check if the columns are sufficient in
connection with their reinforcements and I will simultaneously cross check the results of
STEREOSTATIKA.
Figure 0-3 Design with the use of Excel
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Bending check:
30 , 6
Loadcombination: 4B(thiswastheleastbeneficialloadcombinationinaccordancetoSTEREOSTATIKA)
Reactions
119.9 KN
11.9 KNm
28.7 KNm
Data
h (mm) b (mm) Cover (mm) Link (mm) R/C bar (mm) Fyk Fck
300 200 30 6 14 360 18
= + +12 = 43
= 257
= = 157
= 46
<
= 183
= + = 54
.
= + = 35
= 1 = 0.89(0.3 < < 1.0)
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= 35
4 :
=0.14 0.15
= 0.11
= 0.25 => =
= 0.11
In connection with the existing column 1C3: 200 300mm, the reinforcement is only
< and therefore my conclusion is that it needs to be reinforced.
5.1.3. Output - ResultsThe next step is to turn again to STEREOSTATIKA but in this occasion the dimensions of the
section will be altered from 300 200mm to 400 300mm and the program will be evaluated
again subject to the new input parameters.
Following the above, I will take the new results N ,M which have already
taken into account the least beneficial load combination of each column subject to
STEREOSTATIKA.
The below figures 5-4 and 5-5 are showing the new section for column 3
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Figure 0-4- new section of 1C3
Figure 0-5-Showing the new section of 1C3 (plan)
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At figures 5.6 and 5.7 in below you can see the process of calculations with the use of
STEREOSTATIKA
Figure 0-6-Calculation and Design process for the proposed section
Figure 0-7-Element problem check from STEREOSTATIKA
It has been observed that by increasing the dimension of the section of 1C3, this leades to
positive results and the set column no longer encounters adequacy problems (reference to
figure 5.7).
1C3
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To conclude I will repeat the procedure via the use of the manual method in Excel for the
same column (1C3). However, the difference being that the dimension of the section has
now been increased to 400 300mm as well as the grade of concrete has been altered from
C25 to C30/37 (factored) and the grade of steel has been altered from S400 to B500
(factored). In addition, I will not take into account the existing reinforcement in the range of 30%
and I will make use of the remaining 70% in connection with the new dimensions of the
problematic columns and in that way I will reach to the final design of the dimensions of the
columns which will be performed via the jacketing method.
For Column 1C3
Bending check:
Loadcombination: 2C
Reactions
99.9KN
71.8KNm
93.1KNm
Data
h (mm) b (mm) Cover (mm) Link (mm) R/C bar (mm) Fyk Fck
400 300 30 10 14 450 27
= + +12 = 47
=
= =
= 203
<
= 368
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= + = 198
.
= + = 143
= 1 = 0.97(0.3 < < 1.0)
= 143
8 :
=0.12 0.15
= 0.03
= 0.25 => =
= 0.11
70% 4 14 + 8 18 430 + 2036
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5.1.4. Final Results:
For Column 1C3
Herein below (figure 5.8) you can see the proposed section which is result from thecalculations.
Proposed Section of 1C3:
Figure 0-8-Design of jacket-section for 1C3
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Chapter 66.1 Discussion
The results that have been reached can be characterized as positive and impressive since in
certain occasions (for instance in figure 6.1) column 1C3 following the increase of its
dimension no longer encountered a capacity problem. In addition, it was observed that by
increasing the dimension of 1C3, columns IC7 and IC25 were relieved from the extra load
that was affecting them.
As the owner of the building, this result was extremely encouraging since it could
mean that by combing strategically a combination of particular columns which would have
relieved the problematic columns from the extra burden I would have incurred an economic
advantage since a considerable amount would have not have been spend in reinforcing all
the columns.
However, by being professional and with the aim of ensuring the absolute safety and
durability of the structure, I have decided that the safest approach is to proceed with the
reinforcement of all columns respectively irrespective of the results deduced via the use of
STEREOSTATIKA (see figure 6.1).
Figure 0-1-Results of Element problem check
1C7
1C3 1C25
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6.1.1. General ConclusionsFirst and foremost the biggest disadvantage of STEREOSTATIKA is that it cannot analyze
and design the dimension of a column via the jacketing method. Nowadays concrete grade
C20/25 is no longer being used for columns and instead concrete grade C30/37 is being used.
Therefore, in connection with my own calculations I had to proceed with a percentage of 10%
C30 C28 and the same was affected with respect to steel grade (10% B500 B450).
STEREOSTATIKA does not provide the option of calculating a dimension in connection with
the inner part of an existing column with a concrete grade C20/25 and with steel grade S400
and with concrete grade C30/37 and steel grade B500 in the perimeter of the existing
dimension.
In addition, another important problem associated with the use of STEREOSTATIKA
is that the grade for concrete and steel are predetermined in the set software and therefore
you are not allowed to insert your own evaluation. For instance, you are precluded to
evaluate that a column which is in the category of grade C30 is instead in the category of
grade C28. In certain occasions, such evaluation might be necessary in order to
accommodate the risk that the given building is an old construction and hence such an
evaluation is necessary for safety reasons. Therefore, you are forced to undertake the
aforementioned action manually or via the use of different software. The same is applicable
with respect to steel. Personally, I decided that with respect to the new dimension the
beneficial capacity of the existing reinforcement is limited to the range of 70%.
Despite the aforementioned disadvantages associated with the use of
STEREOSTATICA, the set software has certain advantages. For instance the 3D graphs'
are simple in their use. I was also enabled in a rather simple and fast track way to alter the
parameters of the dimensions of the columns, to reach to solutions and to repeat the same
procedure numerous times so as to ensure the best possible result.
Following the review of an extensive bibliographical study and several design projects
in connection with the retrofit of structures, it can be concluded that there are some outlines
that are helpful, not only in a qualitative but in a quantitative manner, the design of a retrofit
scheme of a structure by means of concrete jacketing.
Although these guidelines can constitute a rational basis for a practical design,
further research needs to be undertaken so as to address certain critical aspects in the
behavior of jacketed elements. The change encountered in the behavior of jacketed
elements, whose shear span/depth ratios are significantly reduced due to their jacketing
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needs to be further clarified. The conventional design guidelines related to flexural concrete
elements can provide un-conservative results when they are applied to the design of such
members. Experimental research needs to further address this issue, including without
limitation the further study of biaxial bending effects on the behavior of wide columns.
To conclude, the procedure of reinforcing the columns by reinforced concrete must
take place once there is a full knowledge and understanding of the extend of the problem. In
parallel, it is absolutely necessary to ensure that the works to be performed are being
thoroughly supervised. The problems related to the actual construction and the experience of
the civil engineer entrusted with the role of supervision will determine whether the
reinforcement will be effected in an economic and efficient way. It is noteworthy to provide the
undisputed fact that the cost associated with the reinforcement is on numerous occasions
greater than the cost related to the initiation of a "new" construction due to the fact that the
reinforcement is interconnected with demolition, welds, grout and an inability to use
mechanical means.
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Chapter 7References
1. Antonopoulos, CP and Triantafillou, TC (2003) Experimental Investigation of FRP-
Strengthened R.C. Beam-Column Joints. J. Composites and Construction, ASCE, 7(1),
pp. 39.
2. Bacque, J Patnaik, AK and Rizkalla, SH (2003) Analytical Models for Concrete
Confined with FRP Tubes. J. Composites and Construction, ASCE, 7(1), pp. 31-38.
3. Choi, KK and Xiao, Y (2010) Analytical Studies of Concrete-Filled Circular Steel Tubes
under Axial Compression. J. Structural Engineering, ASCE, 136(5), pp. 565-578.
4. Cosenzo, E and Ivervolino, I (2007) Case Study Seismic Retrofitting of a Medieval Bell
Tower with FRP,” Journal of Composites for Construction, ASCE, 11(3), pp. 319-327.
5. Hamid. AA Mohmond, ADS and El Magal, SA (1994) Strengthening and Repair of Un-
reinforced Masonry Structures: State-of-the-art, Proceedings of the 10th International
Brick and Block Masonry Conference, Vol. 2, Elsevier Applied Science, London, pp.
485-497.
6. Kendall, D (2007) Building the Future with FRP Composites.Reinforced Plastics, May,
pp. 26-33.
7. Minicelli, F and Tegola, LA (2007), Strengthening Masonry Columns: Steel Strands
Versus FRP, Proceedings of the Institution of Civil Engineers Construction Materials Vol.
160, Issue CM2, May, pp. 47-55.
8. Mishra, A (2010) Arresting Leakges on the Inside Walls of Inspection Gallery (Muran
Dam) of Upper Indravathi Hydro Electric Project, Orissa, India – A Case Study, Int. J 3
R’s, (1)2, pp. 87 – 89.
9. Mullians, G Sen, R Suh, K and Winters, D (2005) Underwater Failure-Reinforced
Polymers Repair of Prestressed Piles in the Allen Creek Bridges, J. Composites and
Construction, ASCE, 9(2), pp.136-146.
10. Nanda, R and Sahoo, DK (2010) Restoration of a Heritage University Building – A Case
Study, Int. J.of 3 R’s, 1(2), pp. 84 – 86.
11. Yeh, YK and Mo YL (2005) Shear Retrofit of Hollow Bridge Piers with Carbon Fibers-
Reinforced Polymers Sheets, J. Composites and Construction, ASCE, 9(4), pp.327-336.
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APPENDIX - ASolutions for the rest of Columns
For 1C4:FOR COLUMN: 1C4PROPOSED As (mm2) : 1440
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 1-Design of jacket-section for 1C4
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For 1C5:
FOR COLUMN: 1C5PROPOSED As (mm2) : 1080
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 2-Design of jacket-section for 1C5
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For 1C6:
FOR COLUMN: 1C6PROPOSED As (mm2) : 1080
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 3-Design of jacket-section for 1C6
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
59 | P a g e
For 1C7:
FOR COLUMN: 1C7PROPOSED As (mm2) : 720
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 4-Design of jacket-section for 1C7
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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For 1C10:
FOR COLUMN: 1C10PROPOSED As (mm2) : 1224
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 5-Design of jacket-section for 1C10
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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For 1C11:
FOR COLUMN: 1C11PROPOSED As (mm2) : 1080
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 6-Design of jacket-section for 1C11
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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For 1C12:
FOR COLUMN: 1C12PROPOSED As (mm2) : 1080
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 7-Design of jacket-section for 1C12
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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For 1C21:
FOR COLUMN: 1C21PROPOSED As (mm2) : 720
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 8-Design of jacket-section for 1C21
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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For 1C25:
FOR COLUMN: 1C25PROPOSED As (mm2) : 864
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 9-Design of jacket-section for 1C25
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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For 1C27:
FOR COLUMN: 1C27PROPOSED As (mm2) : 720
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 10-Design of jacket-section for 1C27
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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For 1C28:
FOR COLUMN: 1C28PROPOSED As (mm2) : 720
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 11-Design of jacket-section for 1C28
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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For 1C29:
FOR COLUMN: 1C29PROPOSED As (mm2) : 720
EXIST CONDITION h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
As(mm2)
S.F30%
300 200 30 400 20 6 4Y14 616
PROVIDE (JACK) h
(mm)
b
(mm)
Cover
(mm)
Fyk
S.F
10%
Fck
S.F
10%
Link
(mm)
R/C
bar
A's(mm2)
400 300 30 500 30 10 8Y14 1232
1663 mm2
Figure A 12-Design of jacket-section for 1C29
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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The plan view of first floor with the final sections in below:
Figure A 13-Plan view of first floor
Figure A 14-3D view with the final sections-first floor
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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APPENDIX - BTutorial
The adequacy of the building components of the existing RC building
Calculation procedure for Case 1:
Input Data to STEREOSTATIKA
Input all of the parameters in accordance with the existing condition of the RC building;
Building regulation:
Figure B 1-RC Building regulation
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
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Specify Materials - Concrete and its properties in accordance to EC 2:
Figure B 2-Specify Concrete and his properties accordance to EC 2
Specify Materials - Rebar Steel and his properties accordance to EC 3:
Figure B 3-Rebar Steel and its properties in accordance to EC 3
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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Specify Materials - Stirrups Steel and his properties accordance to EC 3:
Figure B 4-Stirrups Steel and his properties accordance to EC 3
Specify Materials - Steel section and his properties accordance to EC 3:
Figure B 5-Steel section and his properties accordance to EC 3
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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Specify Ground type and properties:
Figure B 6-Ground type and properties
Specify Earthquake risk zone accordance to EC 8:
Figure B 7-Earthquake risk zone accordance to EC 8
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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Specify Stiffness Parameters:
Figure B 8-Stiffness Parameters
Specify Space Frame Parameters:
Figure B 9-Space Frame Parameters
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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Specify Units:
Figure B 10-Specify Units
Import the data for Design Analysis:
Figure B 11-Design Assumptions
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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the user can choose the solver button and subsequently Static and Dynamic analysis of the
model is performed, taking into account the calculation parameters set. The solver utilizes
the Complete Quadratic Combination (CQC) modal combination method. From the central
screen of the program, choosing Parameters > Space Frame Parameters (NTUA) the user
can select the solution method (CQC of seismic forces or CQC of Seismic Forces on MC + 4
Ecc).
During the dynamic analysis, the program performs all calculations and determines
the number of modes needed and all other design data (Eigen values, member loads, load
combinations, member deformations, reinforcement mm2 demands in every section of the
model etc) which is important for the correct estimation of the building’s response.
Then after all the necessary data are calculated, the reinforcement area demand (As,cal) for
each structural element is determined. This is an automated procedure and no user
intervention is needed.
Then all necessary data for further processing the project are created, namely all construction
drawings (formwork and reinforcement drawings) based on the reinforcement calculated on
the previous step.
After the conclusion of all calculations, element design, estimations and generation of
detailing construction drawings, the user is advised to continue to Element Problems Checkand Reinforcement Edit.
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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As you can see the results for the Case 1:
Problem report
Summary of element checks:
Elements with problems: 0
Figure B 12-3D model of exist structure showing the element checks with colors
In view of the fact that none of the elements encounters problems, I proceed with the
discussion of Case 2 which relates to the addition of an extra storey.
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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Calculation procedure for Case 2:
Input new data to STEREOSTATIKA and apply the same procedure provided in connection
with Case 1;
The results in connection with Case 2 are as follows:
Problem reportSummary of element checks:Elements with problems: 13
Figure B 13-3D model of design structure showing the element checks with colors
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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APPENDIX - C
EXCEL FORMULAE – THE FIVE STEP ANALYSIS
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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Short description of how each Step works so that other users can make use of these formulas.
Step 1With respect to step 1 you proceed to input the data (Nd, Mxd, Myd)
Step 2In terms of step 2 there 3 subcategories:
a) First in subcategory (a) you input the safety factor for the existing section and for the
proposed section to be designed (note the s.f. values will be subject to your own
evaluation).
b) Second in subcategory (b) you input the characteristic compressive strength of
concrete and the characteristic yield strength of reinforcement both in respect of the
existing section and proposed section.
c) Thirdly with respect to subcategory (c) you input the data with respect to:
1) Dimensions of the section
2) The cover
3) The links diameter
4) R/C bar diameter
Step 3With respect to step 3 automatically the calculations are undertaken.
Step 4In connection with step 4 we take the last three results and we apply them to the relevant
tables and as a result we get a particular value which we input to step 4 and it will result to
the final cross sectional area of reinforcement.
George Georgiou Ch. - Static Equilibrium of an existing two storey structure with the future
January 2014 Perspective of adding an additional storey -
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Step 5With respect to the last step as you can establish there two columns.
a) With respect to the first column:
i. you input the safety factor for the existing steel reinforcement (note the s.f. values
will be subject to your own evaluation),
ii. the number of the existing steel-bars and their diameter
b) In terms of the second column you input the number of the proposed steel-bars to be
designed and their diameter.
Again automatic calculations will be undertaken and the program itself will verify whether the
proposed cross sectional area of reinforcement have adequate capacity.