The 1st lnternational Conference of European Asian CiviI Engineering Forum EACEF

F=

E:i:: E::l:: fhe future de,vel*pryl*rlt in'civit engifie*ring hased sn rssearcl"I end E-:. E:::::

e* - ?7 September 20Sr *l the {Jnjv*rsitas Felita H*rapen, 4.. Lippc Karawaci, Jakarta tl.tDOl.tfSlA

Organized by

:ffi: Universitiit stuttsart #_u3lj ':i1::::::iif' Germany Proceeding CiviI Engineering Department rsBN 978-979-1 053-01 -3 ISBN 978-979- r 053-o 1 -g

. : -'' international Conference of EACEF ! - :.;,i -lsiarL Ciail EngirLeering Fonun)

PROCEEDTNG

The FUTURE, DEVtrLOPMtrNT in STRUCTURAL and CIVIL trNGINEE,RING BASED on RESEARCH and PRACTICAL EXPERIENCE

26 - 27 September 2OO7

at the Universitas Pelita Harapan Lippo Karawaci, Jakarta

Editors Wiryanto Dewobroto (Chief ednor) Harianto Hardj asapu tr a (G eo techni que / S tructur e) Jack Widjajakusuma (Material)

Frans is cus Mintar F. Sihotan g (Infr a s tructur e) Manlian R. Adventu s (Cons truction M ana g ement)

Graphic Design Eston K. Mauleti 3,oup of Structure and Construction

:Flper ID , .,-: \lurugadoss J., Rajendran M.G., Priya Vaijayanthi R., "Paralielisation of EACEF-02 '.1-.trple Ant Colonies Using Master-Slave Approach for Structural ,::rmisation", Bamari Amman Institute of Technology, Sathyamangalam and :,::'.urva Deemed University, Coirnbatore, TN, INDIA. - I.l.:lrood Md Tahir, Anis Saggaff, Arizu Sulairnan, Shek Poi Ngian, EACEF-04 S:::rdardisation of Pa(ial Strength Cornposite Connections Using Pre-Fabricated >.::1 Sections", Steel Technology Centre, Universiti Teknologi Malaysia, :,.,,dai. Johor, MALAYSIA Rendy Thamrin and Tetsuzo Kaku, "Experimental Study on Flexural and Bond EACEF-06 Behavior of RC Beam with CFRP Bars" , Depaftment of Civil Engineering, , INDONESIA ; and Department of Architectural and Civil Engineering, Toyohashi University of Technology, JAPAN

-. : Hemmati and Ali Kheyroddin , "3-D Nonlinear Analysis for Seismic EACEF.lO -.ss:ssment of Vertically Mixed Structures", Departrnent of Civil Engineering, - :. :ineering Faculty, Islarnic Azad University, Semnan Branch, IRAN and -::afiment of Civil Engineering, Engineering Faculty, Semnan University, -:_{\ Wiryanto Dewobroto, Sugeng Wijanto,Ign. Toto Ismintarto ,"The Application of EACEF-I4 STM (based on ACI 3 l8-02) and FEA for the Design of Structural Transfer-Wall - Case study : 'Kota Kasablanka' Mixed Use Project, Jakarta", Universitas Pelita Harapan - Lippo Karawaci; - Jakarta and PT. Gistama Intisemesta Consulting Engineers - Jakarta, INDONESIA. -: ;1eep M. and Pratima Rani Bose, "Combination of High Frequency Modes in EACEF-I5 :..srlic Analysis of Irregular Buildings" , Department of Civil Engineering, -- - ,1ege of Science and Technology, Royal University of Bhutan, Phuentsholing, : IUTAN; and Department of Civil Engineering, Delhi College of Engineering, l':,iri. NDIA lM. Sigit Dannawan, "Comparison of Truss Model for Shear of Reinforced EACEF-19 Soncrete Beams", Department of Civil Engineering, Sepuluh November Institute rf Technology, Surabaya, INDONESIA Herman Parung, "Numerical Modeling of composite Structures: comparison EACEF-2I Between Analytical and Experimental Results", Departrnent of Civil Engineering, Faculty of Engineering, , Makassar, INDONESIA Karl-Heinz Reineck, "Shear Design Integrated in The Design Concept of Strut- EACEF-28 and-Tie Models for Structural Concrete", ILEK-Institut flir Leichtbau Entwerfen und Konstruieren (Institute for Lightweight Structures Conceptual and Structural Design), University of Stuttgart, Stuttgaft, GERMANY **Invited Speaker +* -.:-.-qin Yang, Jian-lin Zhang, "Optimal Design of Darnping Devices Installed EACEF.34 -':\\ een Two Adjacent Parallel Strucfurcs", Department of Civil Engineering, ''- :rren University, Xiamen, People's Republic of CHINA '- and Shyh-Jiann Hwang, "Prediction of Load-Deflection Responses of EACEF-39 I -,-rble-Cur.'rature RC Squat Walls, Dept. of Civil Engineenng, Universitas :-,sten Indonesia,INDONESIA also Ph.D Candidate, National Taiwan - :.rr ersity of Science and Technology, TAIWAN and Department of Civil '---:ineering, National Taiwan University, also National center for Research on : ;::hquake Engineering, Taipei, TAIWAN '. -, \\-ei'wei : Li Zhitao ; Ding Hanshan ;Liu Zhao ; Cao Sanpeng, "Theory And EACEF-43 : del Experiment Of Smart Prestressed Beam" , College of Civil Engineering, -. - -.:heast University, Nanjing, Jiangsu Province, People's Republic of CHINA

Ptliro Iltrropon, Lippo Kttruu,aci, INDONESIA, 26-27 Septetnber 2007 roc-3 Group of Structure and Construction

EACEF-52 13 Olga Pattipawaej, Yosafat A. Pranata and Tiara E. Rachmanda, "Analysis of Pylon Cabte Stayed Bridge due to Wind Load", Civil Engineering Department, Maranatha Chri sti an University, Bandun g, INDONESIA 14 Aswandy, "Buckling Behaviour of Members With intermediate Discrete Lateral EACEF-54 Restrainis Under Bending and Axial Compression : Numerical Simulations and Applicarion of EUROCODE 3",Institut Teknologi Nasional (ITENAS), Bandung, INDONESIA

15 Jing Deng-hu and cao Shuang-yin, "HazardDiscussion on Masonry Arch EACEF-55 Stn]cture with Joints Damage Under Vertical Loading", Southeast University,

16 Yosafat Aji Pranata and Anang Kristianto, "Hinge Properties Modeling for EACEF-60 Behavior and Perfbrmance Evaluation of RC-Shearwall Buildings", civil Engineering Department, Maranatha Christian University, Bandung, INDONESIA l/ Rildova, Dyah Kusumastuti, and Nurita Handayani, "Optirnal Placement of EACE,F-63 Multiple Tuned Mass Dampers to Improve Structural Performance of Building undeiEarthquake Excitation", Faculty of Civil and Environmental Engineering, Institute of Technology Bandung, Bandung, INDONESIA

18 Iskandar, Dyah Kusumastuti, Bambang Budiono, and Herlien D. Setio,'Non- EACEF-68 linear Finite Element Analysis of RC Beam-Composite Column Joint Under Cyclic Loading", Department of Civil Engineering, Polytechnic of Llokseumawe, Aceh, INDONESIA ;Faculty of Civil Engineering and Environmental Engineering, Institute of Technology BandlngJNDONESIA. 19 Ding Hanshan, wang Peng, Huang Jian, Xia wengjun,zhangYigui and zhang EACEF-69 ..Application Rui, of External CFRP Prestressing on Hewei Bridge in china", Southeast university, GHINA; Department of communications of Jiangsu province, CHINA ; Highway Department of Huai'an Municipality, CHINA. 20 Titik Penta Artiningsih, "Effects of The opening Location on Partially EACEF-75 Prestressed Concrete Hybrid T-Beams of Normal - Lightrveight Concrete", Civil Engineering Study Program, Engineering Faculty, Pakuan University, , INDONESIA

21 yoyong Arfiadi and Muhamrrad N.S. Hadi, "Moment Coefficients for Statically EACEF-76 Indeterminate Prestressed Concrete Structures",Department of Civil Engineering, Atma Jaya Yogyakarta University, INDONESIA and Faculty of Engineering, University of Wollongong, AUSTRALIA 22 Yoyong Arfiadi, "Flexible Mounted Tuned Liquid Column Dampers for EACEF-77 Reducing Structural Response", Department of Civil Engineering, Atma Jaya Yogyakarta University, Yogyakarta, INDONESIA 23 I.K. Sudarsana and M. Sukrawa, "Flexural Strengthening of T-Beam Bridge EACEF-83 Girder Using Extemal Laminate of CFRP Sheets", Member of HAKI and Civil Engineerin g D epartment, Univers ity of UdaVqa-_B a!i.$-pNE ! IA 24 Wang Chunlin and Lu Zhitao, "Dynamic Characteristics and Seismic Response of EACEF-97 Core-Tube with Semi-Flexible Suspension Systems Linked by Darnpers", Key Laboratory of R.c. & P.c. Structures, Ministry of Education and Southeast University, Nanjing, Jiangsu, P.R. CHINA 25 M. Bourezane and L.Belounar, "New Strain Based Shell Element with Drilling EACEF-10.+ Rotation", Civil Engineering Department, Biskra University, ALGERIA

roc-4 The l'' Inlerntrtionctl Conference ctf European Asian Civil Engineering Fortttt: Group of Structure and Construction EACEF-083

FLEXURAL STRENGTHENING Of T.BEAM BRIDGE GIRDER USING EXTERNAL LAMINATE Of CFRP SHEETS

I K. Sudarsana and M. Sukrawa

Lecturer at Civil Eng. Department, {Jniversity of Udayana, Bali-Indonesia, member of HAKI E-mail : civil2 00 I ca@Yahoo. com

ABSTRACT : This experimental research investigates behavior of external laminate CFRP flexural strengthening of T-beams of a 15 meter length which is part of a typical T-beam bridge designed based on Indonesian Highway Authority, Bina Marga Standard. Three scaled T-beam models of l:4 were cast and tested to failure. The difference among those models is the number of the CFRP layer which is 0 (specimen control), I and 2 layers, respectively. The CFRP sheets were bonded on tension side of the beam using epoxy resin. The specimens were tested under 2 point loading to simulate truck loads according io BMS with a dynamic load amplification (DLA) of 0.3. Three mechanical gauges were installed to measured beam deflections during the test' The experimental results show that external flexural strengthening using CFRP sheets was able to reduce irack widths and cracks spacing as well as to delay the occurrence of initial cracks. The T- beam with one layer of CFRP sheet increased the strength and stiffness of the beams by 9,75o/o and ll,45o ,respectively, of that of the control beam, with the failure mode dictated by the rupture of the CFRp. The T-beammodel with 2layers of CFRP sheets increased the strength and stiffiress of the control beam by 18.06% and 14.92Yo, respectively, with shear failure mode followed by CFRP debonding. The later results show that increasing the number of CFRP layer to strengthen the flexural capacity of the beams is less effective unless it is combined with shear strengthening

KEYWORDS: Retrofit, CFRP sheet, Bridge, RC T-Beam.

1. INTRODUCTION

1.1 Background The external strengthening method for reinforced concrete, RC T-beam of bridges can be applied by means of glued Cfnp sheets on tension side of beam using epoxy resin. The main advantages of the technique are simple and easy to apply without any traffic interruption. In Indonesia, there are many T-beam bridges built for the past few decades because it is the most cost effective type for short bridge with span fengtfr up to 25 meters. In the near future, the bridges need repairing, strengthening, or replacement due to ages, overly loaded, up-grading of road class, and exposure to weather and corrosive environment, which reduce its serviceability and strength. Considering optimum use of budget, strengthening method is preferable to replacement or building new bridges. Therefore, the streigtirening efforts-for RC T-beam bridge girder using external laminate of CFRP sheets or other mateiials is worth investigated. In this study, CFRP sheets are used for flexural strengthening because it has resistant to corrosive environment and flexibility to the beam surfaces.

Strengthening of RC structural member using external laminate CFRP sheets has been investigated extensively. th. ,." of CFRP sheet for flexural strengthening of beams is able to increase flexural capacity of beams (Ritchie et.al, 1991; Shahawy et.al, 1995; Shahawy and Beitelman, 1999)' In addition, initial cracking loads and beam stiffness can be increased and reduce the crack widths and spacing (Ritchie et.al,l99l Shahawy et.al, 1995; Bonacci and Maalej, 2001).

1.2 Research Significance

There are many RC T-beams built for highway bridges of span up to 25 meters. In the near future, the bridges need rlpairing, strengthening, or replacement due to ages, overly loaded, up-grading of road clasi and to weather and corrosive environment, which reduce its serviceability and strength. fne"*po.ur" aAdition of CFRP sheets by gluing it to tension side of beam will considerably increases

c-172 EACEF - The l'' International Conference of European Asian Civil Engineering For:,": EACEF-083 Group of Structure and Construction

deflection and the stiffness and flexural strength of the beam. The increased stiffnesswill reducesthe the method are simple, non- increases the crack load of thi beam. Other significant advantages of corrosive and free of traffic interruption. Therefore. application of this concept for retrofitting an process, especially existing RC T-beam bridge will give significant flexibility on bridge strengthening for the-bridges located aicorrosive environment, as well as extend the service life of the bridges and improve the load carrying capacity.

2. EXPERIMENTAL PROGRAM Department Three 1/4 scaled RC T-beams were cast and tested to failure at structure Laboratory of of Civil Engineering, Faculty of Engineering, University of Udayana. The first beam is used for control (BC), th; r""onJb"u, ii strengthened with one layer of CFRP sheet (BSl), and the third beam is .t .ngtf,"n.d with two layer of bfRp sheets (BS2). All the T-beams have the same dimensions and reinf|rcement which is directly scaled from the prototype T-beam of Bina Marga standard for simple program was span bridge of l5 meter span length. The main variable investigated in this experimental the effeciof the number of CFRP layer used to strengthen the beams. More details on experimental programs are presented in the following sections'

2.l PrototyPe T-Beam

In this experiment, T-beam of Bina Marga Standard for the span length of 15 meters was selected arbitrarily as prototype beam, as part of a bridge with 9.92 meter width, consisting of two traffic lane and pedestrian meaiuring 7 meters and I meter, respectively. The T-beam bridge of BM 100 classifications has six main girders of total depth of 1050 mm with flange of 1700 mm wide, and 200 (25.4 mm thick, and web thickness of 450 mm. The tension reinforcement is 22D1" mm) at mid span and 8D1,, bars near the supports. The compression steel used is 10D1" bars near the supports and 8D1,, at mid span. The beams also have side reinforcement of 2Dll2" (12.8 mm) with Vertical shear reinforcement of D3/8" (9.5 mm) spaced at 200 mm and diagonal steel of 16D1". The specified concrete strength iriizs'orzz5k{im2,equalto 18.31 MPa, wiih steelyield strength of 2400 kglcmz ortJ24 equal to 235.3 MPa.

2.2T-Beam Specimens

The model T-Beam was designed as a direct strength model, where similar materials were designed for both prototype and model structures (Sabnis et al., 1983). A length scale factor of ll4 was used to minimize the cost and to fit the laboratory conditions. As a result, the dimension of the T-beam specimen is 3750 mm long with flange of 425 x 50 mm and web of 112.5 x 212.5 mm. the ."info.""rn"nt is 5D10.6 mm in tension and 2D6.7 mm in compression with vertical and diagonal 1(a) (b). shear reinforcement of D3.5 at 140 mm spacing and2D6.7 at2l5 spacing as shown in Fig. &

Micro concrete mix with specified compressive strength of 18.31 MPa was designed to have the same properties as that of the piototype by modeling its target compressive strength (f",) of 27.15 MPa. i..taturat gravels with maximum iir" of l0 mm were used for coarse aggregate and regular sand was used to ivoid a large proportion of fines that require more absorption water._Using a water cement ratio of 0.65, the final mix proportion by weight is l:2.87:4.31 (cement : fine aggregate : coarse aggregate).There was no attempt to scale the weight of the structure due to the effect of material clirtiltu"nt density on the concrete properties. The yield strength of reinforcing bar (plain bar) having diameter 10.6 mm were determinedfrom laboratory test. It was found that the rebar yield strength (fr) is 366 MPa, with maximum tension strength and tension rupture of the rebar ate 522,2 MPa and 381,3 Mpa, respectively. These bars can be categorized as U32. The yield strength of the rebars differs from that of specified ior the prototype (1J24), therefore, corrections were done on reinforcement area used in the model. The scale factor-for the rebar area was adjusted from 16 to 21.33 (= 16 x (3212$).The properties of CFRP sheet used in this experimental research are 0.13 mm thick and 80 mm wide with a fabric specified tensile strength of 3500 MPa.

a '-'. tJniversitas Pelita Harapan, INDONESIA - September 26-2/h, 2007 Group of Structure and Construction EACEF-083

2.3 Test Setup and Instrumentation In the test progrim, the truck load was modeled as two point loads simulating the middle and rear a:

Loading and unloading of the T-beam specimens were done at increment rate of I lclr{/minute. Prior to testing of BS1 and BS2, the CFRP sheets were glued on tension surface of the beam, respectively one layer and two layers. The control beam @C) was tested in 4 cycles of loading, and the beam BS1 and BS2 were loaded in 5 load cycles. The maximum target load increment for each loading cycles was 16.25 ld{. After reaching the target maximum load on each cycle, the load was gradually released back to zero value indicated on the load meter. The mid span deflections were measured using dial gauges. In addition, the crack measurements include length, spacing, and width were taken regularly during loading and unloading process up to specimen failure using a crack detector with accuracy up to 0.01 mm. Fig. 1(a) and (b) shows experimental set up and cross section of model T-beam, respectively. The applied load history is shown in Fig. 1(c).

Pt2 P12

t40 140 r-fI 2ts 215-T--T 215 215 - I +-+ #',+-

(a) Experimental set up

2 6s.00 O 15 6 48.75 FI 32.50

16.2s

0.00 2 3 4 No. of cycler

O) Beam cross section (c) Applied loading history

Figure 1. Experimental set up and cross section of model T-beams

3. RESI]LTS AI\D DISCUSSION

Testing of T-beams was conducted after the model beams cured at 28 days. The average compresst-. . strength of model concrete was 2'7.72 MPa which is higher than the target strength of 21.1-i \IP' How.ever, the difference is not imporlant as comparison is made within the same concrete stren-:.: The corresponding test results are as follows.

c- 1--+ EACEF - The l"t International Conference ofEuropean Asian Civil Engineeing F.--- Group of Structure and Construction EACEF-o83

3.1 Crack Patterns

At the testing of control beam (BC), flexural cracks developed first between two points loading at rcglon of maximum bending moment. As the loads were increased, other new cracks occur and the existing cracks progress toward the beam flanges. Once the flexural cracks reach the bottom surface of the flanges, these cracks stop and inclined shear cracks occurs and progressively progress toward the fsam flanges causing beam failure. The shear cracks occur at a distance 300 mm from the point load or 1075 mm from the beam support where there was no inclined shear reinforcement added.

Trble 1. First Cracking loads and widths

Been Po P* %P* Crackwidttrs (w) ( Type od\o 0d\n fld\n (--) | t(il,i/u[ iLll]\,IfNIn\ (!) 48.61% (35.00) 0.50 Beam Control (BC) BC 7.00 72.00 67.71% (48.7s) 1.00 94.44% (68.00\ 1.80 41.14%(32.50) 0.15 (b) Beam with one layer CFRP sheet BSl 15.00 79.00 61.71% (48.7s) 0.20 82.28%(65.00\ 0.25 38.24%(32.50) 0.10 B52 19.00 85.00 57.35% /48.7s\ 0.15 (c) Beam with two layer CFRP sheet 76.47% (6s.00\ 0.20 Figure 2. Crack Patterns of beam after failure

The addition of CFRP sheet on tension surface of the beam (BS1 and BS2) was able to delay the occlurence and progression of the first cracks. Moreover, the width and spacing of the cracks decrease as the CFRP sheet added to the control beam as shown in Fig.2. The crack developments and patterns observed in this experiment were similar to those of reported in Ritchie et al. (1991), Shahawy et al. (1995) and Bames & Mays (1999).

Table 1 shows the first cracking loads and crack widths for three condition of loads namely !40o/o, +600/0 and +80% of the ultimate failure loads. It is shown that the addition of CFRP sheet to flexural strengthened the beam reduces the crack width up to 5 times of that of control beam (BC) and the first crack loads increase 128.6% and 174%o for addition of one and two layer of CFRP sheets, respectively.

3.2 Deflections of T-Beam

Deflections of the specimens were measured at beam middle span for every load increment of 1 k}'[/minute both at loading and unloading stages. Under the service load simulating by the first loading cycle of 16.25 kN, the confrol beam (BC) deflects as much as 3.6 mm, and when the load was released back to zero there was a permanent (residual) deflection of 1.2 mm caused by beam cracks. Comparing the deflection of this loading stage, it is found that the measured value of 3.6 mm n % scale beam or 14.4 mm in prototype beam is still smaller than the standard permissible deflection of T- Beam for bridge of L/800 which corresponds to 19 mm. At following loading cycles, the maximum load of 32.5 kN produced maximum deflections of 8 mm with the value of residual deflection of 4.0 mm. The complete graph of load-deflection relationship for BC is shown in Fig.3. It is also apparent from the graph that yielding of the reinforcement is reached at the load of 67 kN with mid span deflection of 22mm.

Universitas Pelita Harapan, INDONESU -September 26-2V! 2007 Group of Structure and Construction EACEF-083

90------

80 D 70

60

50

40

30

20

10

1000 2000 3000 4000 5000 6000 7000 8000 Deflection (1/100 mml

Figure 3. Load-deflection relationship of the control beam (BC)

The T-Beam strengthened with CFRP sheet (BSl and BS2) behaved in similar manner to the control beam (BC) with smaller deflection value. Fig. 4 shows the load-deflection relationship for the strengthened beams. The first loading cycle produced maximum deflection of 1.7 mm with residual value of 0.3 mm which are less than that of the control beam. After the first cycle, the slope of the curve changes due to cracking. Yielding of the reinforcement occurred after the fourth loading cycles when the loads reached 75 kN and 76 kN for BSl and BS2, respectively.

90------� E 80

70 D

60

Remarks: Remarks: A-)P= 16,25kN( Ix truckload) A "'?P-= 16,25 kN( 1 x truckload ) 8-)P = 32,50 kN( 2 x truckload) B "'7P=32,50k.N ( 2x truck load) C-) P -48,75 kN( 3 x truckload) C "'7= P 48,75kN ( 3 x truckload) D 7 P-65,00kN ( 4 x truck load) D 7P =65,00 kN(4x truckload) E 7 P = 79,00 kN (CFRP rupture) 10 E 7 P - 85,00 kN (CFRP debonding)

1 000 2000 3000 4000 5000 6000 7000 8000 1000 2000 3000 4000 5000 6000 7000 8000 Deflections (1/100 mm) Deflections (1/ 100 mm) (a) Midspan deflection ofBSl (b) Midspan deflection ofBS2

Figure 4. Load-deflection relationship of T-Beam strengthened using CFRP sheets

When the load released back to zero after reaching the maximum load of fourth cycle, there were permanent (residual) deflections of 6.8 mm and 4.5 mm, respectively, for T-Beam BSl and BS2 as shown in Fig. 4. The residual deflections are due to the beam cracks to be not recovered completely. These results indicate that increasing the number of CFRP layer, the ability of the T-Beam to recover the cracks increases.

3.3 Stiffness

The stiffness of the T-Beam was studied using the slope of the backbone curves developed from the load-deflections relationship due to repeated loading as shown in Fig. 5. It is shown from the graph that the T-Beams strengthened with CFRP sheets (BSl and BS2) have higher stiffness than that of the control beam at condition of service load or up to the maximum load of the first loading cycle. The stiffness of BSl and BS2 increase by 11.45% and 14.92%, respectively, from that of control beam. The increase in the BSl and BS2 stiffness is consistent with the first crack development in those beam as described in Section 3 .1.

C-1 6 EACEF - The F' InternationalConference of European Asian Civil Engineering Forum ,.-r:.-lp ol Struchrre and Construction EACEF-083

z 60 -5Uo 't, 8+o FI 30

10

0 .6000 0 1000 2000 3000 4000 Sooo 70oo Sooo . Deflections(1/ lOOmmf tr'igure 5. Backbone curves of the load-deflections of BC, BS1 and BS2

After the first crack occuffed, there was no significant improvement on the BS1 and BS2 stiffness because the CFRP sheet having thickness of 0.13 mm and 80 mm wide contributes very little on the beam inertia, hence the beam stiffness.

3.4 Failure Modes and Ultimate Capacity Behavior of the T-beam under ultimate loads was also of interest pertaining to the effect of additional CFRP sheets to strengthen the RC T-beam. Such behavior was measured after the loading cycles in which indications of reinforcement yielding occur. After this condition, the loads were increased continuously until the beam failure. The control beam fails due to shear after significant flexural cracks occur and yielding of the reinforcement atthe ultimate load of 72 kN which is 39.4%, higher than the predicted ultimate load of 51.66 kN. Considering the maximum service load value of 16.25 kN, the control beam exhibits a safety factor of 4.43.

The strengthened T-beam with one layer CFRP sheet (BS1) fail due to CFRp rupture at the ultimate load of 79 kN which is 22.14o/o higher than the predicted ultimate load of 64.68 kN. For the T-beam strengthened with 2layers of CFRP sheet (BS2), the beam fail due to shear followed by CFRP debonding at the ultimate load of 85 kN which is 9.62Yo higher than the predicted ultimate load of 77.54 kN. Comparing the failure loads of both strengihened beams with the maximum service load, safety factor of 4.86 and 5.23 is obtained for BS1 and BS2, respectively.

All of the beams fail after the reinforcement reaches its yield stress. Table 2 presents the capacity of tested beams at yield and ultimate conditions. It is shown in Table 2 that the use of CFRp sheets to flexural strengthen the T-beam increases the ultimate beam capacity of g.72yo for BS1 and l8.06Yo for BS2 in comparison with the control beam capacity. Fig. 6 and Fig.7 show conditions of the beams after failure for the control beam and the strengthened ones, respectively.

Table 2. C ity of the tested beams Beam Pyiel

BC 67.00 72.00 49.50 Shear Failure

BS1 75.00 79.00 54.31 CFRP rupture

B52 76.00 85.00 s8.44

Figure 6. Failure mode of the control beam rBC r

Universitos Peli.ta Harapan, INDONESIA -Septentber 26-)71t,, 2007 EACEF-083 Group ol Structure and Construction

(a) T-Beam BS1 (b) T-Beam BS2

Figure 7. Failure of the tested beam strengthened with CFRP sheets

4. CONCLUSIONS of CFRP Based on the experimental results and discussions, it can be concluded that the addition the beam as sheets glued oniension side of RC T-Beam is effective in increasing the stiffness of service well as-reducing the number, width, and height of cracks developed in the beam. Under the beam load, the stiffne-ss of the beam BS1 and BS2 rs 1l.45Yo and 14.92% higher than that of is control, respectively. The reduction on crack widths due to external laminate of CFRP sheets up to i times of the crack width of the control beam. The first cracking loads increase up to 12g.6% and 171.40/o of that of the control beam. The strengthening method also significantly (BC), the increases the flexural strength of the T-beam. In comparison with the control beam ultimate strength of the strengthened beams (BS1 and BS2) is 9.72% and 18.06% higher, respectively, ,iith fuilrne modei due to CRII rupture for the BS1 and shear followed by CFRP debonding for the BS2. In this study, the control beam fails due to shear failure.

5. ACKNOWLEDGEMENTS

at This research has been possible with financial supports from Department of Civil Engineering University of Udayana. The authors would like to thank PT. Sika Indonesia through CV. Jaya Raya Utama, Bali for donating CFRP Sheets and epoxy resin. Special thanks are due to colieagues at the department ior their input and comments during various stages of the experimental Progmm.

6. REF'ERENCES

Barnes, RA dan Mays, G.C.(1999). "Fatigue Performanse of Concrete Beams Strengthened With CFRpPiates,,. Journal of Composite of Construction, Vol.3, No.2, Mei. pp 63-72 6'Behavioral Bonacci, J.F. and Maalej, M. (2001). Trends of RC Beams Strengthened With Externally Bonden FRP". Joumal of Composite for Construction, Vol. 5, No.2, Mei. pp 102-l 13. ..An Hewitt, B.E. (1972). Investigation of the Punching Strength of Restrained Slabs with particular Preference to tne Deck Slabs of Composite I-Beam Bridges," Ph.D- Thesis, Dep. of Civil Egr., Queen's Univ. at Kingston, Canada' .oPerilaku Lembar Prayitno, F.A. (2004). Balok -T Jembatan dengan Perkuatan Lentur CFRp,, Tugas Akhir, Program Sarjana, Program Studi Teknik Sipil, FT, Universitas Udayana. of Ritchie, P.A., Thomas, D.A., Lu, L.W., Connelly, G.M. (1991). "External Reinforcement Concrete Beams Using f iber Reinforced Plastics". Technical Paper, ACI Stnrcrural Journal,Vol 88, No.4,Juli-Agustus. pp 490-400

C-I-S EACEF - The l"' International Conference of European Asian Civil Eng

E Group of Structure and Construction EACEF-083

Sabnis, G.M., Harris, H.G., White, R.N., and Mirza, M.S. (1983). "Structural Modeling and Experimental Techniques." Prentice-Hall, Inc., Eanglewood Cliffs,NJ. 07632.

Shahawy, M.A., Arockiasamy, M., Beitelman, T., Sowrirajan, R. (1995). "Reinforced Concrete rectangular Beams Strengthened With CFRP Laminates". Structures Research Centre, Florida Departement of Transportation, 2007 E. Paul Dirac Drive, Tallahassee, FL 32310, USA

Shahawy, M and Beitelman, T. (1999). "Static and Fatigue Performance of RC Beams Strengthened With CFRP Laminates". Journal of Structural Engineering, Vol.125, No.6, Juni. pp 613-621

Sukrawa, M., Pringgana, G., Sudarsana, IK. (2006). "Behavior of RC T-Beams Strengthened with Steel Plate". Proceeding of 2nd Asian Concrete Federation Conference, Nusa Dua-Bali, Indonesia, November 20-21.

Universitas Pelita Harapan. INDONES/A - September 26-27th, 2007 C-