Jl-13-Winter-11 - An Architectural Vision Realized Through Engineering.

7/29/2019 Jl-13-Winter-11 - An Architectural Vision Realized Through Engineering.

1/15 6PCI Journal|Winter 2013

The conceptual plans o an academic center or nano-technology research were developed in the springo 2009. The research center is a 60 40 m (200 130 t) two-story, 11 m (36 t) high building surrounded byan atrium that is enclosed by a structural acade archi-tecturally designed to represent the lattice structure o a

carbon nanotube (Fig. 1).

The 134 m (440 t) long structural acade consists o 7.3 m(24.0 t) high and 500 mm (20 in.) thick preabricatedstructural elements o C60 (8700 psi) white concrete thatare aligned along two curves partially surrounding therectangular ootprint o the building. The structural acadeis constructed o 53 preabricated units o three dier-ent types and encloses an unobstructed atrium space oapproximately 1185 m2 (12,750 t2) around the two-storybuilding. The approximate surace area o the atrium is3000 m2 (32,000 t2). The atrium is capped by an insulated

concrete roo with an area o 1800 m2 (19,400 t2) andweight o 560 kg/m2 (945 lb/yd2) that is supported on steelbeams spanning the variable atrium space. The span is amaximum o 15 m (49 t) and cantilevers over the struc-tural acade at a maximum extension o 7 m (23 t).

The structure is located in the highly seismic Marmararegion o Western Anatolia in Turkey. The area requires de-sign or absolute ground acceleration value o 0.4g, whereg is acceleration due to gravity. The structure is exposedto winter conditions with possible ice ormation and snowloads o 100 kg/m2 (20 lb/t2). The annual ambient tem-

peratures vary rom -5C (23F) to 40C (104F), and the

This paper describes the design and construction of a prefab-

ricated structural concrete facade of a university nanomaterials

laboratory.

The precast concrete lattice pattern on the facade mimics the

nanostructure of the materials.

The structural design met the requirements of seismic resis-

tance, as was demonstrated by a minor earthquake that occurred

during construction.

An architectural visionrealized through prefabrication

zgr Bezgin


2/15Winter 2013 |PCI Journal4

preabricated structural acade that also ormed the archi-tectural boundary o the atrium are discussed in this paper.

The structural acade o the research center is alignedalong two curves that are dened rom ve ocal points.The entrance to the atrium is through the overlapped partso the two curves.

The acade elements were developed as a lattice structure.The 500 mm (20 in.) thick preabricated panels not onlyhouse thermally insulated layered windows at middepthbut also unction as a tilted light unnel that maximizes theinusion o natural daylight into the atrium.

In addition to its important structural unction as a supportelement or the roo, the 1000 m2 (10,800 t2) preabricatedacade also orms the vertical ace o the structure. There-ore, the design o the acade incorporated architectural,unctional, and structural requirements. The architecturalrequirement or providing refectivity and visibility o theacade through the structural element required the design othe concrete mixture to satisy not only structural and du-rability requirements but also the unctional requirement orefectivity. Due to its low iron oxide content, white cementis up to two times more refective than gray cement. Theuse o white cement in the concrete provides the required

architectural refectivity without a special refective coating.

annual ambient relative humidity values vary rom 50% to100%.

Functional characteristics

The research center was built using several dierentconstruction materials and techniques. The two-storyrectangular building is a cast-in-place reinorced con-crete structure o C30 (4400 psi) concrete with interiorreinorced masonry walls. The atrium consists o preab-ricated, insulated C60 (8700 psi) white concrete acadeelements. The roo is made o C30concrete reinorcedwith lattice steel overlying galvanized ribbed steel deckingthat spans between steel beams. The steel beams rest on

steel belt beams that are continuously supported along thetop o the acade elements. The connections between thesteel roo beams and the steel belt beams and the connec-tions between the steel belt beams and the preabricatedconcrete structural acade elements allow rotation betweenthe connected elements.

Multiglass panels in thermally insulated aluminum ramesare embedded within the preabricated and insulatedacade elements. Due to the dierences in techniques andmaterials used in its construction, the design and construc-tion o the research center was completed in stages by

dierent contractors. The design and construction o the

Figure 1. Perspective view o the structural atrium acade.



rods along their heights, through the contacting elbows oneighboring elements. The belt beam and rods limit rela-tive movement between the precast concrete units duringconstruction. They also limit the degrees o reedom orvibrations to occur through the acade and provide redun-dancy or the transer o loads among the preabricatedelements.

The steel roo beams that are composite with the rein-orced concrete roo slab are supported by the preabri-cated structural acade elements. The connection allowsor the rotation o the beams, preventing the developmento xity moments at the top o the cantilevered acade ele-ments.

Figure 3 shows the cross section o the roo slab. Thebeam connections allow ree rotation under the action oservice loads. The bolts engage axially under the possibleaction o pounding in the event o an earthquake and pro-vide partial xity limited by the yield strength o the boltsin the event o ultimate loading on the roo.

The erection o the preabricated structural acade ele-ments had an in-plane erection tolerance o 5 mm (0.20 in.)and an out-o-plane erection tolerance o 0.02 rad. Duringthe design phase, the individual elements were designed to

resist loads individually.

The design o the preabricated structural elements notonly included the service loads and ultimate loads but alsoloads generated during construction and installation.

Moments, shears, and axial loads are generated within thepreabricated structural acade elements under the action oimposed axial and lateral loading rom the roo. In additionto the bending moments, shear, and axial loads, torsionalstresses were expected due to the diagonal positioning othe lattice elements between the nodes o the preabricated

acade elements.

The structural acade had to be transparent enough to al-low the inusion o daylight while having the strength andductility to support the lateral and vertical loads due to theheavy roo. The solution to these two conficting require-ments resulted in 30% o the total acade area dedicated tothe solid structural elements, with the remaining 70% madeup o the windows.

Structural characteristics

The structural acade o the research center consists o53 preabricated elements, o which there are three types.Following their production and shipment, the preabricatedstructural elements were installed into sockets that wereconstructed as a continuous strip oundation or the totallength o the acade. Figure2 shows the three types opreabricated acade elements that constitute the acade.

There are thirty 3.0 m (10 t) wide type 1 elements, twenty1.5 m (4.9 t) wide type 2 elements, and three triangulartype 3 elements with a maximum width o 4.5 m (14.8 t).The type 3 elements are the bounding elements o the twocurves along which the acade is positioned. type 1 andtype 3 elements weigh approximately 70 kN (15.5 kip)each, and type 2 elements weigh 35 kN (7.7 kip) each.

The beams that support the roo plate are supported by thepreabricated acade elements every 3 m (10 t) along theacade. The roo plate that spans between the two-storystructure and the acade has variable spans. Thereore,the load on each o the precast concrete structural acadeelements is dierent. Rather than designing and produc-

ing each o the 53 preabricated concrete acade elementsor dierent load conditions, the elements were designedor our maximum loading values that were determinedby dividing the roo slab into our separate regions with aspecial consideration or the roo along the region wherethe two acade curves overlap.

The roo loads that are collected by the radial beams aretranserred to the belt beam that is aligned along the topo the acade. The belt beams are supported by the acadeelements at discrete locations on top o steel plates that arewelded to steel plates embedded in the acade elements

during production. Thus, the acade elements collectandtranser gravity loads rom their point o contact with theroo belt beam to the socketed oundation. The preabri-cated structural acade elements were designed or gravityservice load values o a minimum o 127 kN (28.7 kip) anda maximum o 490 kN (110 kip). Design considerations orthe ultimate loads required the design o the preabricatedstructural acade elements or a minimum o 181.3 kN(41 kip) and a maximum o 735 kN (165.4 kip).

The precast concrete elements were designed to withstandthe imposed design loads individually. However, they

were also connected by the belt beam at the top and by

Figure 2. Preabricated acade element types. Note: all measurements are in

millimeters. 1 mm = 0.0394 in.

7300

1500 1500150015001500

1100


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To provide the required strength and ductility, a doublyreinorced solution was used that increased the allowablesteel ratio o the particular cross section to 6.5%.

The preabricated acade elements not only had to bestrong enough to support the vertical loads imposed by

the roo and lateral loads imposed by the defection o theroo attached to the main building but also to allow thehousing o windowpanes within limited defections andprevent pane racture under the construction and serviceloads.

Durability considerations led to limited service loadstresses and associated crack widths because the elementswere not to be coated or durability and protection. The

Tight connement o the concrete was critical due to theanticipated triaxial stresses. With the eective depth o thesection at 160 mm (6.3 in.) along the axis where the in-plane bending takes place, the shear reinorcement spacingwas limited to a maximum o 80 mm (3 in.).

The continuous reinorcement, each with a total length o9.2 m (30 t), was bent at 10 locations to ollow the con-guration o the preabricated structural acade elements.Longitudinal structural continuity was necessary becausethe concrete cross section did not accommodate reinorce-ment overlap. The vertical reinorcement was coupled atthe nodes by ties along the ull widths o the nodes.Figure 4 shows the elevation views o the reinorcementor the three types o preabricated structural acade ele-ments that were produced. Figure5 shows a typical crosssection o a lattice element, excluding the shear stud, and atypical plan view o a node.

The diameter o the longitudinal reinorcement variedrom 22 to 26 mm (0.87 to 1.02 in.) depending on the loadimposed on the preabricated elements along the acade.

Each layer o the acade was designed such that theconcrete was not stressed beyond 50% o the compressivestrength under service load. The moment design valuesrequired the use o doubly reinorced sections because therequired ductility could not be provided by single side rein-orced sections. The maximum steel ratio or a single sidereinorced C60 (8700 psi) concrete section was ound to be

3.6%, which was less than the required steel ratio o 4.7%. Figure 4. Elevation view o steel reinorcements within the preabricated acadetypes.

Type 1 Type 2 Type 3

Figure 3. Connections between the steel radial and belt beams with the preabricated acade. Note: all measurements are in millimeters. 1 mm = 0.0394 in.



highlight o preabrication or this project was the one-step production o preabricated concrete elements that metthe structural, architectural, and unctional requirements.

With the development o high-strength materials and ad-vanced preabrication methods, slender preabricated ele-ments with limited stiness can be designed and produced.Thereore, the explicit service load design o reinorcedconcrete elements, which is considered by the author to beimplicitly and insuciently covered in ultimate strength

based reinorced concrete design guidelines, becomesall the more important in the design and construction oprecast concrete.

Another important aspect o preabrication in this projectwas the strength development o the concrete. The pro-duction and shipment o precast concrete elements occurbeore the concrete reaches the design strength. A particu-larly important phase o preabrication is the removal othe orms. The economically optimal use o ormwork andrate o production required that demolding take place assoon as possible. Early strength as well as 28-day strength

o the concrete was closely monitored to rapidly mold anddemold the preabricated products.

Figure 6 shows the variation o strength based on thecollected samples or the statistical strength evaluation othe preabricated acade elements that were designed or astrength o 60 MPa (8.7 ksi).

The statistical evaluation presented in Fig. 6 was based onan assumed Gaussian distribution, and the samples wereound to yield a 95% condence or the required concretedesign strength. Similar statistical studies were also con-

ducted or 1- and 7-day strengths o the concrete mixture.

The high-early-strength white cement allowed the attain-ment o C20 (2900 psi) class within 24 hours, sucient topermit orm removal.

To estimate displacements at dierent times, the developmento the elastic modulus o the concrete was considered accord-ing to the variation o the concrete elastic modulus suggestedby the Turkish standard Requirements for Design and Con-struction of Reinforced Concrete Structures, TS-500.1

The installation o the windowpanes was a critical stepthat was careully coordinated with the glass producer sothat they could be installed any time ater the erection othe preabricated elements. Thereore, the glass producerhad to be supplied with the estimated deormations o theloaded preabricated acade elements.

The architectural design yielded a limited cross-sectionalarea with which to meet the serviceability and strengthrequirements. The limit where the design concrete strengthand design crack width is reached has been extended andimproved with the addition o compression steel that eases,

redistributes, and reduces the development and value ostress in the concrete and limits the crack widths.

The sections were designed so that they were not stressedunder service loads beyond 50% o the compressive strengtho the concrete. It was determined rom numerous compres-sion tests or the concrete used in the design that the behavioro the high-strength concrete was linear up to approximately55% o its compressive strength. The limited compressivestresses under service loads coupled with double reinorce-ment around the perimeter o the cross section (Fig. 7) yieldeda ductile and strong structural cross section that satised the

structural requirements or all o the stages o production and

Figure 5. Typical diagonal cross section and reinorcement plan at the node. Note: all measurements are in millimeters. 1 mm = 0.0394 in.



installation. The design reinorcement requirements resultedin the use o 26 mm (1 in.) reinorcing bars along the 200 mm(8.0 in.) wide part o the section and 16 mm (0.63 in.) rein-orcing bar along the 100 mm (4.0 in.) wide part.

Based on the cross-sectional dimensions in Fig. 7, the

strength design requirements based on the heaviest weakaxis design moment value were determined to be:

Mu = (3383)(100) = 0.9(4.285)(138)(138)2

required = 0.039

where

Mu = ultimate moment

Mn = nominal moment strength

= steel ratio

fy = yield strength o steel

b = width o equivalent concrete section

d = depth o equivalent concrete section

= average depth constant o the resultant compres-sive orce with respect to the concrete strength

Figure 6. Unconfned 28-day cylinder compressive strength values o samples. Note: 1 MPa = 0.145 ksi.

Figure 7. Structural evaluation o reinorced concrete diagonal cross section.Note: all measurements are in millimeters. 1 mm = 0.0394 in.

50

11

6

100

116

175

2

00

137

101

138

138

175

101

138

17

5x

y



where

singlesided= steel ratio or singly reinorced concrete section

compression = steel ratio or doubly reinorced concrete section

= steel compressive stress

= uEs

= (0.003)(200,000)

= 273 MPa (39.6 ksi)

where

Es = elastic modulus o steel

c = distance between the outermost part o compressivesection and the neutral axis

cp = distance between the compressive steel and the neu-tral axis

b = (0.7)(0.0478) + (0.556) = 0.063

0.063 > required = 0.039

Another reason or incorporating the compressive steel

was to increase stiness or serviceability concerns. Theamount o double reinorcement used was more thanrequired in terms o strength design, providing double rein-orcement with a limit higher than the required reinorce-ment level o 3.9%. The service design o slender pre-abricated structural elements needed to be evaluated orservice load considerations. The exposed concrete struc-ture not only had to satisy structural design requirementsbut also architectural and durability requirements. There-ore cracks had to be limited, both in size and number, andthe deormations had to be limited to required tolerances.Figure 8 illustrates equivalent cross sections o a doubly

reinorced uncracked section and the cracked section.

The neutral axis o the cracked section stressed within itselastic limits is determined to be

+ (n 1)As-top (kdc) = nAs-bot(dkd)

where

k = uncracked depth actor or singly reinorced section

= average stress constant with respect to the con-crete strength

= compressive strength o concrete

required = required steel ratio

Balanced steel ratio:

where

b = balanced steel ratio

u = ultimate concrete strain

y = steel strain at yield

Considering the strain hardening o the reinorcement, ACIsBuilding Code Requirements for Structural Concrete (ACI

318-05) and Commentary (ACI 318R-05)2 limit or the steelratio was ound to be at 75% o the balanced value and theTS-500 limitation to be at 70% o the balanced value deter-mined based on the elasticperectly plastic behavior.

lim(TS-500) = 0.70d= (0.70)(0.0478) = 0.033

lim(ACI-318-05) = 0.75d= (0.7= (0.75)(0.0478) = 0.036

where

lim(TS-500) = limiting steel ratio according to the TS-500

lim(ACI 318-05) = limiting steel ratio according to ACI 318-05

The required reinorcement ratio was greater than that al-lowed by TS-500 and ACI 318-05. It was decided by thedesigner to doubly reinorce the section, reduce the concretecompressive stresses, and increase the section ductility.

required = 0.039 > b(TS-500) = 0.033

where

b(TS-500) = balanced TS-500 steel ratio

Because the compression steel was close enough to theneutral axis that at ductile ailure the compressive stresswas below the yield stress o steel, the balanced steel ratioor the doubly reinorced section had to be determined bythe compression steel stress value below the yield stress.

sb = 0.7b-singlesided+ compression



I=

= 4583 107 mm4 (110 in.4)

The limited cracking required by the use o double rein-orcement resulted in a stiness reduction due to an 18%reduction in the moment o inertia. The extra reinorce-ment was used to limit the theoretical service load crack-ing and the associated losses in cross-sectional moment oinertia. Without the use o the compression reinorcement,the stiness reduction was determined to be higher than30%, which raised serviceability concerns.

Prefabrication and installation

The design, production, and construction o the structuretook place between March 2009 and August 2010. Thedesign o the preabricated structural elements took ourmonths, with many revisions and consideration o several

core design ideas. The ormwork producer participatedlater in the design stage in generating the constructiondrawings or the preabricated structural acade elements.Composite ber-reinorced plastic ormwork was chosenor its ductility and ease o repair or repeated use. TheC60 (8700 psi) concrete mixture included white cementand white limestone aggregates with a maximum size o10 mm (0.39 in.); it had a slump o 150 mm (5.9 in.).

A continuous reinorcement cage without overlaps wasa challenge to place into a slender ormwork within thetolerances. Ater a couple o trials, the construction o a

complete and continuous reinorcement cage was achieved.A crew o six workers was able to bend and tie the cageor one preabricated structural acade element in onework day. The reinorcing bar content per cubic meter oconcrete in the doubly reinorced sections varied between250 and 350 kg/m3 (420 and 590 lb/yd3). The abrication oa single reinorcing cage or each element allowed ease omaneuvering and placement into the composite ormwork.Figure 9 shows the reinorcement cage or type 1 acadeelements.

The composite ormwork was constructed o a series o

smaller orms that were bolted together at the nodes o

n = modular ratio

As-top = area o steel positioned below the neutral axis

As-bot= area o steel positioned above the neutral axis

The moment o inertia o the doubly reinorced section

cracked up to the tensile steel can be determined rom

I=

=

= 5534 107 mm4 (133 in.4)

where

I = moment o inertia

k2 = uncracked depth actor or doubly reinorced section

rtop = diameter o top reinorcement

rbot= diameter o bottom reinorcement

The moment o inertia o the doubly reinorced sectioncracked up to the neutral axis that occurs when the con-crete varies linearly up to its elastic limit can be deter-mined rom

I=



Concrete was placed ollowing the placement o the top por-tion o the ormwork. The ormwork geometry and materialwere such that 85% o the surace o the cast product wascovered by the ormwork, which acilitated curing.

Without the use o any special curing schemes, the ormswere removed ater 24 hours at a strength grade o C20(2900 psi), which was sucient or the elements to belited and stored or shipment. Each preabricated unit hadour specially designed anchor points that were placedwith respect to the center o gravity o the acade element.The units were lited by an overhead mobile crane andtranserred to the storage area (Fig.11)

The preabricated structural acade elements were shippedto the site 20 km (12 mi) rom the actory in groups o

the nished product. The multi- and sloped-aced acadeelement had many points o contact with the ormwork thathad to be released without excessively orcing and deorm-ing the ormwork. The multipiece design o the ormworkallowed ease o ormwork production, ormwork clean-ing, and the ability to produce the three types o acadeelements with a single repeating unit, thereby lowering

ormwork costs.

The setup o the ormwork, which included the cleaning,bolting, and ne tuning by installing the specially producedsloped shims, required a ull work day or our workers.

Prior to the production o the acade elements, insula-tion layers were precision cut to the dimension requiredbetween the two layers o concrete. Each acade elementhad two reinorcement cages. Following the placement oone cage into the ormwork, the top plates were installedto be connected to the belt beam during installation andthe concrete was placed ollowed by the placement o theinsulation layers. Figure 10 shows a typical preabricationsequence o the initial layer o the preabricated structuralacade element.

Following the placement o the insulation layer, the secondlayer o the reinorcement cage was positioned and shearstuds were installed through the insulation layer. This creat-ed thermal bridging but provided composite action betweenthe two layers o the preabricated structural acade element.

Figure 9. Complete reinorcement cage o a type 1 preabricated acade element.

Figure 8. Hypothetical evaluation o uncracked and cracked doubly reinorced

cross section. Note: As = area o steel; b= width o equivalent concrete section;

d= depth o equivalent concrete section; k= uncracked depth actor or singly

reinorced section; n= modular ratio.

b

kd

d

(n-1)As

nAs



construction. Late in November 2010, an earthquake omoment magnitude 4 occurred in the region. During theearthquake, the installed acade elements showed no signo distress. Figure 13 shows the installation o the type 1and type 3 acade elements into the sockets.

Following their installation, the preabricated structural

acade elements were bolted along the points o contactwith adjacent elements (Fig.14)to prevent relative lateraltranslation between adjacent elements.

Following completion o the acade, the steel beams thatspan between the building and the acade over the atriumspace were installed. Figure15 shows the completedacade and the placement o the steel belt beams and theradial beams. The beams had a xed connection to thebuilding and were simply supported on the acade. Fol-lowing the placement o the beams, corrugated steel deckswere placed between the beams with shear studs thatpenetrated into the cast-in-place concrete roo slab. Theconstruction o the roo was complete with the placemento insulation and a sloped topping. Figure 16 shows theconstruction sequence o the roo beams and the compos-ite roo deck.

The installation o the acade elements took approximatelytwo months, ollowed by the construction o the roo slaband the atrium (Fig. 17).

Following the construction o the acade and during theconstruction o the roo, the window embedded rameswere placed into the acade elements. Deormations under

the imposed loadings were careully estimated within thedesign stage o the preabricated elements and submitted tothe windowpane producer to allow or the deormations andexpected movements in the design and construction o thewindow rames. Figure 18 shows a perspective o the com-pleted atrium a year beore the structures inauguration.

three units (Fig.12). At the site they were unloaded and

placed into socketed strip oundations and later grouted.During this phase o construction, the acade elementswere cantilevered. While the roo support was not present,the acade would have to be supported by its oundation inthe event o an earthquake. Thereore the elements weredesigned to respond as cantilevers in an earthquake during

Figure 10. Insertion o the frst layer o reinorcement o the acade into the

ormwork.

Figure 11. Preabricated acade elements at the stockyard.



Figure 13. Installation o preabricated acade elements into oundation sockets.

Figure 12. Transer o the preabricated acade elements to the construction site.


12/15Winter 2013 |PCI Journal4

Acknowledgments

The author would like to convey his respects to ErsinAr lu, Kksal Anadol, and lk Aro lu or the establish-

ment o the Yap Merkezi Group, where an engineeringideal is always reached. The author would also like toconvey his respects and gratitude to Ba ar Aro lu andMurat ener or the trust and the opportunity that made theperormance or the presented project possible. The authorwould also like to thank Orhan Manzak and mit zkanor their support throughout the project.

Conclusion

Design o the preabricated structural acade with the struc-tural and architectural requirements presented a unique

challenge. The preabricated solution served to advancestructural design and construction techniques as well asprovide a construction solution that met the architecturaland structural requirements o a complex acade systemwith a single-step preabricated construction process.

Figure 14. Connection between the neighboring preabricated acade elements.

Figure 15. Complete preabricated acade structure.



2. ACI (American Concrete Institute) Committee 318.2005.Building Code Requirements for StructuralConcrete (ACI 318-05) and Commentary (ACI 318R-

05). Farmington Hills, MI: ACI.

References

1. TS-500. 2000.Requirements for Design and Con-struction of Reinforced Concrete Structures. TurkishStandards Institute: Bakanlklar, Ankara.

Figure 17. Interior view o the complete atrium space beore internal architectural works.

Figure 16. Installation o the radial steel roo beams and cast-in-place composite concrete roo deck.



I = moment o inertia

k = uncracked depth actor or singly reinorced

section

k2 = uncracked depth actor or doubly reinorcedsection

Mn = nominal moment strength

Mu = ultimate moment

n = modular ratio

rbot = diameter o reinorcement above the neutral

axis

rtop = diameter o reinorcement below the neutralaxis

= average stress constant with respect to theconcrete strength

= average depth constant o the resultant com-pressive orce with respect to the concretestrength

u = ultimate concrete strain

Notation

As = area o steel

As_bot = area o steel below the neutral axis

As_top = area o steel above the neutral axis

b = width o equivalent concrete section

c = distance between the outermost part o com-pressive section and the neutral axis.

cp = distance between the compressive steel and theneutral axis

d = depth o equivalent concrete section

Es = elastic modulus o steel

= compressive strength o concrete

= steel compressive stress

fy = yield strength o steel

g = acceleration due to gravity

Figure 18. Perspective o the acade.


15/15

y = steel strain at yield

= steel ratio

b = balanced steel ratio

b(TS-500) = balanced TS-500 steel ratio

compression = steel ratio or doubly reinorced section

lim(ACI-318) = limiting steel ratio according to ACI-318

lim(TS-500) = limiting steel ratio according to TS-500

required = required steel ratio

singlesided = steel ratio or singly reinorced section

About the author

zgr Bezgin, PhD, is chie o theresearch and developmentdepartment or Yap MerkeziPreabrication Inc. in Istanbul,Turkey. He received his BS incivil engineering rom Polytech-nic University in Brooklyn, N.Y.,

ater an education in physics engineering at HacettepeUniversity in Ankara and MS in structural engineeringand PhD in substructural and geotechnical engineering

rom Rutgers, the State University o New Jersey.Throughout his graduate and proessional studies,Bezgin conducted research and design work in theeld o mechanics o solids, nite element modeling,soil-structure interaction analysis and design andinvestigation o deep oundations and deep excavationsupport structures. Bezgin is also a part-time lecturerin Bosphorus University in Istanbul.

Abstract

This paper describes the design and construction o apreabricated structural concrete acade o a universitylaboratory to study nanomaterials. The precast con-

crete lattice pattern on the building acade mimics thenanostructure o these materials. The structural designmet the requirements o seismic resistance, as wasdemonstrated by a minor earthquake that occurred dur-ing construction. Architectural requirements includedmaximizing natural light inside the laboratory and ahigh degree o refectance. The result is a building witha delicate appearance that is resistant to the seismicityo its location.

Keywords

Composite, doubly reinorced, acade, high-strengthconcrete, preabrication, white cement.

Review policy

This paper was reviewed in accordance with thePrecast/Prestressed Concrete Institutes peer-reviewprocess.

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Jl-13-Winter-11 - An Architectural Vision Realized Through Engineering.

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