Texas Transportation Institute The Texas A&M University System College Station, Texas

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1 1. Rport No. FHWA/TX-05/9-150-P. Govrnmnt Assion No.. Ripint's Catalog No. 4. Titl and Subtitl DESIGN, CONSTRUCTION, AND MAINTENANCE OF BRIDGE DECKS UTILIZING GFRP REINFORCEMENT 5. Rport Dat Fbruary 005 Thnial Rport Doumntation Pag 6. Prorming Organization Cod 7. Author(s) David Trjo, Franiso Aguiñiga, Ray W. Jams, and Ptr B. Kating 9. Prorming Organization Nam and Addrss Txas Transportation Institut Th Txas A&M Univrsity Systm Collg Station, Txas Sponsoring Agny Nam and Addrss Txas Dpartmnt o Transportation Rsarh and Thnology Implmntation Oi P. O. Box 5080 Austin, Txas Prorming Organization Rport No. Produt P 10. Work Unit No. (TRAIS) 11. Contrat or Grant No. Projt Typ o Rport and Priod Covrd Produt 14. Sponsoring Agny Cod 15. Supplmntary Nots Projt prormd in oopration with th Txas Dpartmnt o Transportation and th Fdral Highway Administration. Projt Titl: FRP Rinoring Bars in Bridg Dks URL: Abstrat Fibr-rinord polymrs (FRP) ar bing inrasingly usd in th onstrution industry. On appliation is to us FRP bars as rinormnt in onrt. Baus glass ibr-rinord polymr (GFRP) bars ar now bing usd, guidan is ndd on how to dsign, onstrut, and maintain rinord onrt struturs ontaining this rinormnt. This rport provids a disussion o dsign issus rlatd to GFRPrinord bridg dks and is ollowd by a dsign xampl. Rommndations or possibl modiiations to th 1998 Amrian Assoiation o Stat Highway Oiials (AASHTO) LRFD Bridg Dsign Spiiations ar providd. In addition, som guidlins on th onstrution and maintnan o GFRPrinord systms ar providd. It should b notd that mor rsarh and ild work is ndd to provid standardiz guidlins. This rport provids guidan using th inormation availabl and th usr should us sound nginring judgmnt in th dsign, onstrution, and maintnan o GFRP-rinord struturs. 17. Ky Words GFRP, Strngth, Dsign, Constrution, Maintnan, Strngth Dtrioration. 19. Surity Classi.(o this rport) Unlassiid Form DOT F (8-7) 0. Surity Classi.(o this pag) Unlassiid Rprodution o ompltd pag authorizd 18. Distribution Statmnt No rstritions. This doumnt is availabl to th publi through NTIS: National Thnial Inormation Srvi Springild, Virginia No. o Pags 7. Pri

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3 DESIGN, CONSTRUCTION, AND MAINTENANCE OF BRIDGE DECKS UTILIZING GFRP REINFORCEMENT by David Trjo, PhD Assoiat Prossor and Assoiat Rsarhr Txas A&M Univrsity and Txas Transportation Institut Franiso Aguiñiga, PhD Assistant Prossor Txas A&M Univrsity Kingsvill Ray W. Jams, PhD Assoiat Prossor and Managr, Highway Struturs Program Txas A&M Univrsity and Txas Transportation Institut and Ptr B. Kating, PhD Assoiat Prossor and Assoiat Rsarhr Txas A&M Univrsity and Txas Transportation Institut Produt P Projt Numbr Projt Titl: FRP Rinoring Bars in Bridg Dks Prormd in Coopration with th Txas Dpartmnt o Transportation and th Fdral Highway Administration Fbruary 005 TEXAS TRANSPORTATION INSTITUTE Th Txas A&M Univrsity Systm Collg Station, Txas

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5 DISCLAIMER Th ontnts o this rport rlt th viws o th authors, who ar rsponsibl or th ats and th auray o th data prsntd hrin. Th ontnts do not nssarily rlt th oiial viw or poliis o th Fdral Highway Administration (FHWA) or th Txas Dpartmnt o Transportation (TxDOT). This rport dos not onstitut a standard, spiiation, or rgulation. Th rsarhr in harg o th projt was Dr. David Trjo. v

6 ACKNOWLEDGMENTS This projt was prormd in oopration with th Fdral Highway Administration and th Txas Dpartmnt o Transportation. This rport was writtn by Drs. David Trjo, Franiso Aguiñiga, Ray W. Jams, and Ptr B. Kating. Finanial support or th rsarh was providd by th Fdral Highway Administration, Txas Dpartmnt o Transportation, and th Txas Transportation Institut. Th authors wish to xprss thir gratitud to: Projt Coordinator: Ronald E. Kostr, P.E., TxDOT, Wao Distrit Projt Dirtor: Timothy E. Bradbrry, P.E., TxDOT, Bridg Division Projt Advisors: Don Harly, P.E., Fdral Highway Administration Mary Lou Ralls, P.E., Rtird Stat Bridg Enginr, TxDOT Jo Chappll, P.E., TxDOT, Amarillo Distrit Mark Bloshok, P.E., TxDOT, Bridg Division Kvin Pruski, P.E., TxDOT, Bridg Division Robrt Sarinlla, TxDOT, Constrution Division Paul MDad, TxDOT, Constrution Division Tom Yarbrough, TxDOT, Rsarh Division vi

7 TABLE OF CONTENTS Pag LIST OF FIGURES... viii LIST OF TABLES... ix I. INTRODUCTION... 1 II. ACI 440.1R-0 DESIGN GUIDELINES: REVIEW AND PROPOSED MODIFICATIONS... ACI 440.1R-0 Stion 7. Dsign Matrial Proprtis... ACI 440.1R-0 Stion 8..1 Craking... 6 ACI 440.1R-0 Stion 8.. Dltions... 9 ACI 440.1R-0 Stion 8.. Calulations o Dltion (Dirt Mthod) ACI 440.1R-0 Stion 11.1 Dvlopmnt Lngth o a Straight Bar... 1 Minimum Conrt Covr Introdution to Dsign Exampl Dsign Exampl III. PROPOSED REVISIONS TO THE AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS IV. RECOMMENDED CONSTRUCTION GUIDELINES FOR THE USE OF GFRP REINFORCEMENT V. RECOMMENDED MAINTENANCE GUIDELINES FOR GFRP REINFORCED CONCRETE STRUCTURES VI. SUMMARY REFERENCES vii

8 LIST OF FIGURES Figur Pag 1 Crak Comparison or a 1.1-Inh Conrt Covr....9 Dsign Exampl Tying o GFRP Bars Chair Plamnt or GFRP Rinormnt viii

9 LIST OF TABLES Tabl Pag 1 Tnsil Strngth Rsults and Prditd Valus... 5 ix

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11 I. INTRODUCTION Corrosion o stl rinormnt mbddd in onrt transportation struturs rsults in signiiant osts and ngativly impats th travling publi. Rsarhrs and nginrs hav bn sarhing or altrnativ matrials that do not xhibit th typial xpansion o th stl orrosion produts that rsult in raking and spalling o th onrt ovr. Ths raks and spalls rdu th intgrity o th rinord onrt strutur and an signiiantly rdu th rid quality o th onrt bridg dk. Corrosion o ibr-rinord polymrs (FRP) dos not xhibit xpansion o th orrosion produt and has bn idntiid as a potntial matrial or us in rinord onrt struturs. This rport provids guidan on th dsign, onstrution, and maintnan o bridg dks rinord with glass ibr-rinord polymr (GFRP) onrt rinormnt. This rport rviws th Amrian Conrt Institut (ACI) 440.1R-0 (00), Guid or th Dsign and Constrution o Conrt Rinord with FRP Bars (hrin rrrd to as th ACI 440.1R-0 dsign and onstrution guidlins), and suggsts modiiations as ndd. Th rport also provids proposd rvisions to th 1998 Amrian Assoiation o Stat Highway and Transportation (AASHTO) Load and Rsistan Fator Dsign (LRFD) Bridg Dsign Spiiations. Rommndd onstrution and maintnan guidlins or GFRP-rinord onrt ar also providd. It should b notd that many issus rlatd to th us o GFRP rinormnt rquir urthr rsarh; th rsults prsntd hr ar rom Rport Charatrization o Dsign Paramtrs or Fibr Rinord Polymr Composit Systms, by Trjo t al. (00). It should also b notd that th thr matrials valuatd in Rport wr rom a singl lot rom ah o thr manuaturrs. It was assumd that th matrials rom ths singl lots and manuaturrs rprsnt o th GFRP matrials prsnt in industry. Th radr and/or usr must us good judgmnt and nginring whn applying th ollowing rommndations. 1

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13 II. ACI 440.1R-0 DESIGN GUIDELINES: REVIEW AND PROPOSED MODIFICATIONS This stion rviws th ACI 440.1R-0 dsign and onstrution guidlins (00) as thy rlat to th rsults obtaind in th rsarh rportd in Rport (Trjo t al. 00). Th ACI 440.1R-0 dsign and onstrution guidlins prsnt inormation on th history and us o ibr-rinord polymr (FRP) rinormnt, a dsription o th matrial proprtis o FRP, and ommitt rommndations rlativ to th onstrution o onrt struturs rinord with FRP bars. This doumnt also inluds rommndd matrial rquirmnts, onstrution pratis, and dsign rommndations. Only thos stions o th ACI 440.1R-0 dsign and onstrution guidlins that th rsarhrs bliv ould b improvd and ar rlatd to th us o glass ibr-rinord polymr (GFRP) bars in bridgs ar rviwd. Th irst stion o th ACI 440.1R-0 dsign and onstrution guidlins to b rviwd is Stion 7., Dsign Matrial Proprtis, spiially as rlatd to th nvironmntal rdution ators proposd by th guidlins to b applid to th tnsil strngth o FRP bars rinord with glass ibrs. A rviw o Stion 8., Srviability, ollows. Th srviability stion rviw inluds raking (substion 8..1) and dltions (addrssd in substions 8.. and 8...). Stion 11.1, rgarding th dvlopmnt lngth o straight bars, is also rviwd. Finally, ommnts ar providd in rgard to minimum onrt ovr. ACI 440.1R-0 SECTION 7. DESIGN MATERIAL PROPERTIES Stion 7. o th guidlins indiats that th matrial proprtis providd by th manuaturr should b rdud to aount or long-trm nvironmntal xposur.

14 Th guidlins rommnd that th tnsil strngth should b dtrmind by: C (1) u whr, u Dsign tnsil strngth o FRP, onsidring rdution or srvi nvironmnt (ksi), C E Environmntal rdution ator, * u Guarantd tnsil strngth o an FRP bar dind as th man tnsil strngth o a sampl o tst spimns minus thr tims th standard dviation ( * u u,av σ) (ksi), u,av Avrag tnsil strngth o FRP bars. E * u Th nvironmntal rdution ators givn in th guidlins or GFRP bars ar 0.8 and 0.7 or onrt not xposd to arth and wathr and or onrt xposd to arth and wathr, rsptivly. Th guidlins indiat that th nvironmntal rdution ators ar onsrvativ stimats that aount or tmpratur ts, as long as th matrial is not usd at tmpraturs highr than th glass transition tmpratur o th polymr mployd to manuatur th bars. Th avrag tnsil strngths o th unxposd spimns o th tnsion tsts in Rport (Trjo t al. 00) ar prsntd in olumn o Tabl 1. Th unxposd tnsil strngths, standard dviations, and guarantd tnsil strngths ar shown in olumns and 4, rsptivly, o Tabl 1. Also shown in olumns 5 and 6 o Tabl 1 ar th dsign tnsil strngths omputd using Equation 1. Th smallst masurd tnsil strngth rom any o th xposur onditions at 50 wks is shown in olumn 7 o Tabl 1. Column 8 shows th guarantd tnsil strngth (* u u,av σ) obtaind rom th masurd xposur data at 50 wks. Column 9 prsnts th prditd avrag rsidual tnsil strngth omputd using a valu o λ (bst it to guarantd tnsil strngth) omputd using th mthod dsribd in th tnsil strngth dgradation analysis stion o th moistur absorption tst rsults in Rport (Trjo t al. 00), or a iv-yar xposur priod. Column 10 shows th prditd 4

15 rsidual tnsil strngth using a valu o λ (urv it to lowst masurd data points) dsribd in th tnsil strngth dgradation analysis stion o th moistur absorption tst rsults in Rport (Trjo t al. 00), or a iv-yar xposur priod. Aording to omparisons mad with th rsarh ondutd by Sn t al. (00) as disussd in Rport (Trjo t al. 00) in th tnsil strngth dgradation analysis stion, th rsults prditd that a valu o λ (bst it to guarantd tnsil strngth) an b onsidrd as th uppr bound rsidual tnsil strngths. Th prditions ar onsidrd as uppr bound rsidual strngth valus baus th bars wr xposd unstrssd, and as indiatd by Sn t al., th appliation o a sustaind strss to GFRP bars auss largr strngth rdutions with tim whn th bars ar unstrssd. Bar typ u, avg unxp. S.D. unxp. Tabl 1. Tnsil Strngth Rsults and Prditd Valus. Tnsil strngth (psi) * u unxp. u (C E 0.8) u (C E 0.7) Smallst 50 wks u (psi) Guarantd 50 wks * u (psi) Prditd 5 yars * u (psi) Prditd 5 yars u (psi) (1) () () (4) (5) (6) (7) (8) (9) (10) P 84,588,456 77,19 61,775 54,05 68,616 59,995 5,868 5,798 V1 88,507 7,951 64,655 51,74 45,58 70,969 6,559 55,17 56,90 V 74,471,598 66,676 5,41 46,67 56,609 54,86 46,544 47,6 Comparing th valus prsntd in olumns 6 and 8 o Tabl 1 shows that th valus o olumn 6 ar only 11, 40, and 18 prnt lowr than th valus o olumn 8. Th valus o u rprsnt th dsign tnsil strngth obtaind ollowing ACI 440.1R-0, and inlud an nvironmntal rdution ator or xtrior xposur that is intndd to aount or strngth rdutions surd by GFRP bars ovr th li o th strutur. Th rsults shown indiat that th dsign strngth is slightly largr than th guarantd tnsil strngth atr only on yar o xposur or bar typ P. Sin th rdutions in strngth shown in olumn 8 wr dtrmind or unstrssd spimns, it is xptd that th guarantd tnsil strngth will b lowr in atual srvi onditions, whr th GFRP bars ar strssd. 5

16 A omparison o olumns 6 and 9 o Tabl 1 show that th iv-yar prditd guarantd tnsil strngths ar quivalnt to 0.98, 1., and 1.00 o th dsign strngths prsntd in olumn 6. This indiats that th GFRP bars valuatd in th rsarh an hav a guarantd rsidual tnsil strngth los to th dsign strngth atr only iv yars o unstrssd xposur. As alrady notd, GFRP bars ar xptd to hav a lowr rsidual tnsil strngth whn thy ar strssd in srvi onditions. Glasr t al. (198) ondutd a 10-yar study on th li stimation o S glass/poxy omposits undr sustaind tnsil load. Th spimns wr kpt at a tmpratur btwn 68 F and 8 F and a rlativ humidity btwn 4 and 7 prnt. Th rsarhrs ound that th rsidual tnsil strngth o th spimns ontinuously drasd with tim, vn byond iv yars, at ths rlativly low humidity lvls. Basd on th obsrvations rportd in (Trjo t al. 00) and baus th tnsil strngth o GFRP bars in strssd srvi onditions is xptd to ithr lvl o or ontinu to dgrad atr on yar o xposur, th rsults indiat that th nvironmntal rdution ators givn by th ACI 440.1R-0 dsign and onstrution guidlins may not b onsrvativ. As indiatd in th tnsil strngth dgradation analysis stion o th moistur absorption tst shown in Rport (Trjo t al. 00), it is diiult to mak valid prditions or long priods o tim with th limitd xposur tims studid. It is thror nssary to arry out xposur tsts ovr longr priods o tim to mak rliabl long-trm bhavior prditions. Th appliation o th strngth rdution ators is prsntd in a dsign xampl latr. ACI 440.1R-0 SECTION 8..1 CRACKING Th ACI 440.1R-0 dsign and onstrution guidlins indiat that FRP bars ar orrosion rsistant and, as a rsult, th maximum rak width limitation an b rlaxd whn orrosion o th rinormnt is th main rason or rak-width 6

17 limitations. Th guidlins rommnd using maximum rak width limits o 0.0 inh or xtrior xposur and 0.08 inh or intrior xposur. Th rsults stion o th raking o th onrt slabs tst in Rport (Trjo t al. 00) indiatd that maximum rak width inrass with onrt ovr. Howvr, as indiatd by Bby (1978), although th rak width on th sura o th onrt is a untion o onrt ovr, th rak width at th lvl o th rinormnt ould b approximatly th sam. Thus, it would b bttr to spiy a maximum sura rak width limit that is a untion o onrt ovr i th dgradation o th GFRP bar dpnds on th rak width at th sura o th bar rathr than at th sura o th onrt. Howvr, until rsarh that rlats th dgradation o GFRP bars to rak width at th sura o th onrt and at th sura o th GFRP bar is availabl, no rommndations an b mad. Th ACI 440.1R-0 dsign and onstrution guidlins rommnd using Equation 8-9b (or 8-9) to stimat th maximum rak width o FRP-rinord onrt lmnts. As dsribd in th rsults stion or th raking o onrt slabs tst in Rport (Trjo t al. 00), th ollowing xprssion yilds a good it to th xprimntal data: W max d A β () whr, W max most probabl maximum rak width β h /h 1, h 1 Distan rom th ntroid o th rinormnt to th nutral axis (inh), h Distan rom th xtrm tnsion ibr to th nutral axis (inh), Strss in th rinormnt (ksi), d Bottom ovr masurd rom th ntr o lowst bar (inh), A Twi th dirn btwn th total and tiv dpths multiplid by th width o th stion (tiv ara o onrt surrounding th main rinormnt) dividd by th numbr o bars (inh ). 7

18 Figur 1 ompars Equation with ACI 440.1R-0 Equation 8-9b, th quation proposd by Faza and GangaRao (199), and th xprimntal data obtaind rom this rsarh. Not that th quation by Faza and GangaRao is mor onsrvativ, but past prati has bn to us th bst-it lin quation instad o th mor onsrvativ approah. Th ACI 440.1R-0 maximum rak width limit or xtrior xposur is also shown in Figur 1. Aording to th analysis prsntd in Stion IV o th rport (Trjo t al. 00) in th raking o onrt slabs tst rsults stion, Equation yilds a good prdition o avrag maximum rak width and a bttr prdition than th work don by Faza and GangaRao (199). Prvious to this rsarh, limitd tst rsults wr availabl on maximum rak width o FRP-rinord onrt lmnts, and limitd analysis had bn prormd to valuat th orrlation btwn tst data and proposd quations. It should b notd that Equation was dvlopd basd on xprimnts on slabs only. An appliation o Equation is prsntd in th dsign xampl givn latr. Th xampl prsnts th maximum rak width omputations obtaind using Equation and ACI 440.1R-0 Equations 8-9b and 8-9 shown nxt as Equations and 4, rsptivly: W E β () s max d A E W max 00 β k b d A (4) E whr E s modulus o lastiity o stl (9,000 ksi), E modulus o lastiity o FRP bars (ksi), k b bond modiiation ator with a rommndd valu o 1. or bond strngth btwn FRP bars and onrt (similar to th bond strngth btwn stl bars and onrt), all othr trms wr prviously dind. 8

19 Th rsults o th dsign xampl show that Equations and 4 yild similar maximum rak widths. In addition, th maximum rak widths obtaind with Equations and 4 ar largr, and thror mor onsrvativ, than thos obtaind with Equation Exprimnt Maximum rak width (in.) ACI limit ACI Eq. 8-9b Faza Last Squars C 0.09 Faza ACI Eq. 8-9b ACI Limit FRP bar strss masurd at midspan (psi) Figur 1. Crak Comparisons or a 1.1-Inh Conrt Covr. ACI 440.1R-0 SECTION 8.. DEFLECTIONS Th ACI 440.1R-0 dsign and onstrution guidlins rquir that dltions b limitd in FRP-rinord onrt lxural mmbrs. Th guidlins ollow th dltion limitations o th ACI 18 building od (000), in whih th dltions o rinord onrt lmnts undr immdiat and sustaind stati loads ar limitd. Howvr, th dltion limitations o th ACI 440.1R-0 dsign and onstrution guidlins and th ACI 18 od do not apply to dynami loads, suh as arthquaks, transint winds, or vibration o mahinry. 9

20 Th rsults o th rsarh rportd in Rport (Trjo t al. 00) on th yli loading o onrt bam tsts indiat that th dltions o bams subjtd to million yls o loading with a GFRP bar strss rang o 18.9 ksi inrasd by 78 prnt. This inrmnt was omputd rom a last-squars bst-it lin to th data. Thror, th dltion inras du to yli loading is signiiant and should b aountd or in th ACI 440.1R-0 dsign and onstrution guidlins. In th absn o mor tst data, th ollowing quation an b usd to stimat a lowr bound o th inras in long-trm dltions du to yli loading: y ln( n) (5) Whr, y bam dltion in inhs, n th numbr o yls. Th orrlation oiint btwn bam dltion and th numbr o yls is R Th slop o this quation an b usd to omput dltions du to yli loading o GFRP-rinord onrt mmbrs. An appliation o Equation 5 to stimat dltions du to yli loading is shown in th xampl prsntd latr. Th dsign xampl omputs th dltions o a GFRP-rinord onrt bam subjtd to dad load and th appliation o million yls o an altrnating liv load. Th rsults show an initial dltion du to dad and liv load o 0.7 inhs and a inal dltion du to dad and liv load o 0.47 inhs atr million yls o th liv load. This rprsnts a 7 prnt inras in dltion du to yli load appliation. ACI 440.1R-0 SECTION 8.. CALCULATION OF DEFLECTION (DIRECT METHOD) This stion o th ACI 440.1R-0 dsign and onstrution guidlins prsnts a mthod to omput long-trm dltions o FRP-rinord onrt lmnts using ACI 440.1R-0 Equation 8-14: 10

21 Δ + 0.6ξ Δ (6) ( p sh ) ( i ) sus whr, Δ (p+sh) Additional dltion du to rp and shrinkag undr sustaind loads (mm, inh) (Δi) sus Immdiat dltion du to sustaind loads (srvi loads) (mm, inh) ξ Tim-dpndnt ator or sustaind load dind in th ACI 18 building od (000) Equation 6 an prdit smallr dltions than masurd. Prhaps th biggst advantag o Equation 6 is its simpliity. Howvr, this quation dos not spiially aount or rp o FRP bars. Th mthod dsribd in th rp stion o Stion IV o th rport or th omputation o long-trm dltion o GFRP-rinord onrt lmnts, whih aounts or rp o GFRP bars, is proposd as an altrnativ to Equation 6. Th ollowing quation an b usd to omput th inrmnt in urvatur: B δn A ' δm κ (7) Δ E ( B A I ) and th ollowing quation an b usd to omput th long-trm dltion: y C L A ( κ + κ + κ ) whr, A ara o th ag-adjustd transormd stion, B, irst momnt o th ag-adjustd transormd stion about th top sura, I sond momnt o th ag-adjustd transormd stion about th top sura, rsptivly. κ A, κ B urvaturs at th supports, κ C urvatur at midspan. A, B, and I ar th proprtis o th transormd ara obtaind using th ag-adjustd tiv modulus, E, in th omputation o th transormd ara o th bondd rinormnt. C B (8) 11

22 Long-trm dltion omputations obtaind with Equations 7 and 8 or a bam with a 14 oot span ar shown in th dsign xampl. Th six-month dad load dltions obtaind with Equation 6 ar 0. inhs, and th six-month dad load dltions obtaind with Equations 7 and 8 ar 0.61 inhs. Thus, th six-month dltion du to dad load omputd with th nwly proposd mthod rom this rsarh is qual to thr tims th dltion obtaind with Equation 8-14 rom th ACI 440.1R-0 dsign and onstrution guidlins. 1

23 ACI 440.1R-0 SECTION 11.1 DEVELOPMENT LENGTH OF A STRAIGHT BAR Th dvlopmnt lngth o a straight bar an b omputd with Equation 11- o th ACI 440.1R-0 dsign and onstrution guidlins as ollows: l b d b u (9) 4μ whr, l b Basi dvlopmnt lngth (inh), d b Bar diamtr (inh), u Dsign tnsil strngth o FRP, onsidring rdutions or srvi nvironmnt (ksi), μ Bond strngth btwn FRP bar and onrt (ksi). Th bond tst rsults prsntd in Stion IV o Rport (Trjo t al. 00) indiat that th bond strngth o GFRP bars xposd to an nvironmnt with high tmpratur and moistur was lowr than th bond strngth o spimns xposd outdoors. In addition, th numbr o spimns xposd to ontrolld onditions that aild by pullout was twi th numbr o spimns rom th outdoor xposur group that xprind pullout ailurs. Howvr, this rsarh inludd only a small numbr o sampls. Th displamnt rordd at th loadd nd was largr, on avrag, or th spimns xposd in tmpratur- and moistur-ontrolld onditions than or th spimns xposd outdoors. Ths displamnts ar indiations that bond strngth dgrads ovr tim. ACI 440.1R-0 Equation 11- rognizs that th tnsil strngth o GFRP bars dgrads with tim and yilds a smallr dvlopmnt lngth or a smallr tnsil strngth. Nvrthlss, whn th bond strngth dgrads, th dvlopmnt lngth inrass. This at may mak Equation 9 unonsrvativ. Th dvlopmnt lngth o Equation 9 should dpnd on th ratio o th rat o tnsil strngth dgradation o GFRP bars to th rat o bond strngth dgradation btwn th GFRP bars and 1

24 onrt. Additional rsarh is ndd to bttr stimat both th rat o tnsil strngth dgradation in a givn nvironmnt and th rat o bond dgradation in th sam nvironmnt. Prhaps th simplst way to aount or th bond strngth dgradation would b to apply an nvironmntal rdution ator to th bond strngth. Th bond strngth o FRP bars in onrt dpnds on th omprssiv strngth o onrt, and tsts hav dtrmind th dnominator o Equation 9 to b approximatly.85 ksi. Th ACI 440.1R-0 dsign and onstrution guidlins propos using Equation 11-7: d b u l b (10) 700 whr, u is th dsign tnsil strngth o GFRP. I th basi dvlopmnt lngth o an FRP bar is omputd with this quation, th bar should hav adquat dvlopmnt lngth at th nd o its srvi li, sin this quation inluds an nvironmntal rdution ator (C E ) in u. But, th bond lngth should b suiint to dvlop th ull strngth o th bar whn th bar is put in srvi ( u,av ), as wll as th strngth o th bar whn it is los to th nd o its srvi li ( u ). Thror, th basi dvlopmnt lngth obtaind would b insuiint to dvlop th guarantd tnsil strngth (* u u,av σ u /C E ) or th avrag tnsil strngth ( u,av ) o th GFRP bar whn th strutur is put in srvi. Until suiint data ar availabl to dtrmin th rat o dgradation o th tnsil strngth and th rat o dgradation o th bond strngth, th avrag tnsil strngth should b usd in th omputation o th basi dvlopmnt lngth or GFRP bars, without rduing it by thr standard dviations and without th appliation o th nvironmntal rdution ator as shown in Equation 10. Thus, this rsarh rommnds that th ollowing quation b usd to omput th basi dvlopmnt lngth and should rpla Equation 11-7 in th ACI 440.1R-0 dsign and onstrution guid (00): 14

25 d b u,av l b (11) 700 whr th trms hav alrady bn dind. A dsign xampl latr shows th basi dvlopmnt lngths omputd using Equations 10 and 11 or No. 6 FRP rinormnt. Equation 10 yilds a basi dvlopmnt lngth o 17 inhs and Equation 11 yilds a basi dvlopmnt lngth o 6.4 inhs. Thus, Equation 11 an yild basi dvlopmnt lngths 55 prnt largr than thos obtaind with Equation 10 (ACI 440.1R-0 quation, 11-7). MINIMUM CONCRETE COVER Rsults o th thrmal xpansion o th onrt slabs tst indiat that using 0.75-inh diamtr GFRP bars in 8-inh onrt bridg dks with lar ovrs o 1,, and inhs would not rak undr a tmpratur inras o 54 F rom th onrt stting tmpratur or a onrt omprssiv strngth o 5.88 ksi or highr. Th at that 0.75-inh diamtr GFRP bars ould b saly usd in onrt lmnts subjtd to tmpratur inrass smallr than 54 F or 1-, -, and -inh onrt ovrs ould b usd in th ACI 440.1R-0 dsign and onstrution guidlins to dtrmin minimum onrt ovr rquirmnts. Th onrt ovrs o 1,, and inhs ar quivalnt to 1.,.66, and 4 bar diamtrs, rsptivly. From th rsults o this rsarh it annot b dtrmind whthr th minimum onrt ovr o 1 bar diamtr rommndd by th ACI 440.1R-0 dsign and onstrution guidlins has problms with raking du to thrmal xpansion. Howvr, it an b onludd rom th rsults o this rsarh that a minimum onrt ovr o 1. bar diamtrs would likly not aus thrmal xpansion and raking o typial bridg dks undr normal nvironmntal onditions. INTRODUCTION TO DESIGN EXAMPLE This stion prsnts a dsign xampl that inluds th rommndd modiiations and/or vriiations to th ACI 440.1R-0 dsign and onstrution guidlins. A simply supportd bam subjtd to distributd dad and liv loads is 15

26 dsignd or strngth. Th rsulting dsign stion is thn hkd to satisy dltion, maximum rak width, and rp ruptur strss limits. Th basi dvlopmnt lngth is also omputd. Finally, th bam dltions du to million yls o liv load appliations ar stimatd. DESIGN EXAMPLE Objtiv Dsign a simply supportd rtangular onrt bam with a span o 14 t. Th bam will b in th xtrior o a strutur. Th bam should arry a srvi liv load o w LL 1. kip/t and a suprimposd dad load o w SDL 0.6 kip/t. Th dltion o th bam at six months should not xd l/40, and th instantanous liv load dltion should not xd l/60. GFRP bars rinor th bam. Th avrag tnsil strngth o th GFRP bars is u,av 96 ksi, th standard dviation is (S.D.).5 ksi, and th guarantd tnsil strngth is * u 88.5 ksi. Othr matrial proprtis ar: E 6,79 ksi and 4 ksi. Assum th bam has adquat shar strngth. Assum th bam will b urd or 7 days and irst loadd at 14 days o ag. Comput th basi dvlopmnt lngth o th GFRP rinormnt. Estimat th bam midspan dltion atr million yls o loading du to an altrnating liv load. Figur shows a dsign basd on th modiid ACI 440.1R-0 dsign and onstrution guidlins. 16

27 Dsign basd on ACI 440.1R-0 dsign guidlins 1. Estimat th bam siz. Estimat th dpth o a simply supportd rinord onrt bam rom Tabl 9.5(a) o th ACI 18 od. Dltions, howvr, nd to b hkd. l h 16 in. ( 14 t)( 1 t ) h 10.5 in. 16 Sin GFRP bars hav lowr stinss than stl bars, gratr dpth than stl-rinord onrt may b rquird or dltion ontrol Dsign basd on rsults rom this rsarh projt 1. Estimat th bam siz. Estimat th dpth o a simply supportd rinord onrt bam rom Tabl 9.5(a) o th ACI 18 od. Dltions, howvr, nd to b hkd. l h 16 in. ( 14 t)( 1 t ) h 10.5 in. 16 Sin GFRP bars hav lowr stinss than stl bars, gratr dpth than stl-rinord onrt may b rquird or dltion ontrol 17 Try h 16 inhs Try b 10.5 inhs. Fatord load Comput th distributd dad load: w w + w. DL ( 10.5 in. )( 16 in. ) ( ) in. ( 1 t ) SDL w p 775 lb lb DL t t Comput th total atord load u ( ) ( ) kip kip kip. t t t w u DL SW w 1.4w w. LL Try h 16 inhs Try b 10.5 inhs. Fatord load Comput th distributd dad load: w w + w. DL ( 10.5 in. )( 16 in. ) ( ) in. ( 1 t ) SDL w p 775 lb lb DL t t Comput th total atord load u ( ) ( ) kip kip kip. t t t w u DL SW w 1.4w w. LL Figur : Dsign Exampl.

28 18 Dsign basd on ACI 440.1R-0 dsign guidlins. Comput th dsign strngth. For a bam loatd in an xtrior spa an nvironmntal rdution ator (C E ) o 0.7 is usd. Th dsign ruptur strngth is: * C u u E u ( )( ) ksi 6.0 ksi 4. Dtrmin th ara o GFRP bars rquird or lxural strngth. Fatord momnt dmand at midspan: wul M u 8 (.1 kip )( ) t 14 t M u 76.6 kip t 8 Baland rinormnt ratio: ' E ε u ρ b 0.85 β1 E ε + ρ b u u u ( 679)( 0.00) ( ) ( )( ) ρ b For a ailur ontrolld by onrt rushing, th rinormnt ratio should b at last 1.4 ρ b. I ρ 1.4 ρ b, th strngth rdution ator is Dsign basd on rsults rom this rsarh projt. Comput th dsign strngth. For a bam loatd in an xtrior spa an nvironmntal rdution ator (C E ) o 0.70 is usd. Th dsign ruptur strngth is: * C u E u ( )( ) u ksi 6.0 ksi 4. Dtrmin th ara o GFRP bars rquird or lxural strngth. Fatord momnt dmand at midspan: wul M u 8 (.1 kip )( ) t 14 t M u 76.6 kip t 8 Baland rinormnt ratio: ' E ε u ρ b 0.85 β1 u E ε u + u 4 ( 679)( 0.00) ρ b 0.85 ( 0.85) 6.0 ( 679)( 0.00) ρ b For a ailur ontrolld by onrt rushing, th rinormnt ratio should b at last 1.4 ρ b. I ρ 1.4 ρ b, th strngth rdution ator is Figur : Dsign Exampl. (Continud)

29 Dsign basd on ACI 440.1R-0 dsign guidlins 1.4ρ b Try using 6-No. 6 bars with a ovr o 1.5 inh and No. stirrups: d 16 in (0.74/ ) 1.75 in. A 0.4 in. (6 ).60 in. ρ A bd.60 in. ρ > 1.4ρ b φ in.( 1.75 in.) Dsign basd on rsults rom this rsarh projt 1.4ρ b Try using 6-No.6 bars with a ovr o 1.5 inh and No. stirrups: d 16 in (0.74/ ) 1.75 in. A 0.4 in. (6 ).60 in. ρ A bd.60 in. ρ > 1.4ρ b φ in.( 1.75 in.) 19 Find th FRP bar strss whn th ultimat strain o 0.00 in th onrt is rahd: ( E ε ) ' u 0.85β1 + E ε u 0.5E ε u 4 ρ [ ( ) ] ( 0.85 )( 4 + ) ( 679 )( 0.00 ) 4 0.5( 679)( 0.00) ksi < u 6 ksi Failur ours indd by onrt rushing. u Find th FRP bar strss whn th ultimat strain o 0.00 in th onrt is rahd: ( E ε ) ' u 0.85β1 + E ε u 0.5E ε u 4 ρ [ ( ) ] ( 0.85 )( 4 + ) ( 679 )( 0.00 ) 4 0.5( 679)( 0.00) ksi < u 6 ksi Failur ours indd by onrt rushing. u Figur : Dsign Exampl. (Continud)

30 Dsign basd on ACI 440.1R-0 dsign guidlins Nominal Momnt apaity: ρ M n bd ' ρ (0.0180)(46.4) M n M 185 kip in kip t n ( )( ) ( )( ) Dsign basd on rsults rom this rsarh projt Nominal Momnt apaity: ρ M n bd ' ρ (0.0180)(46.4) M n M 185 kip in kip t n ( )( ) ( )( ) 0 Providd momnt apaity: φ M n M u ( ) φ M n kip t 80.8 kip t φ M n 80.8 kip t Mu 76.6 kip t Th stion has adquat lxural strngth. Minimum rinormnt: ' 5.4 A,min bwd u Th minimum rinormnt rquirmnt dos not nd to b hkd baus th stion is ovr-rinord. Providd momnt apaity: φ M n M u ( ) φ M n kip t 80.8 kip t φ M n 80.8 kip t Mu 76.6 kip t Th stion has adquat lxural strngth. Minimum rinormnt: ' 5.4 A,min bwd u Th minimum rinormnt rquirmnt dos not nd to b hkd baus th stion is ovr-rinord. Figur : Dsign Exampl. (Continud)

31 1 Dsign basd on ACI 440.1R-0 dsign guidlins 5. Chk th short-and long-trm dltions o th bam, Short-trm dltion Gross momnt o inrtia o th bam: bh I g 1 ( 10.5 in. )( 16 in. ) I g 584 in. 1 Modular ratio: E E n E ' psi n psi Nutral axis dpth: k ρ n k k 0.1 I r bd + ( ρ n ) ρ n ( )( 1.74) + [( )( 1.74) ] ( )( 1.74) k + n A d 1 k ( ) Dsign basd on rsults rom this rsarh projt 5. Chk th short-and long-trm dltions o th bam, Short-trm dltion Gross momnt o inrtia o th bam: bh I g 1 ( 10.5 in. )( 16 in. ) I g 584 in. 1 Modular ratio: E E n E ' psi n psi Nutral axis dpth: k ρ n k k 0.1 I r bd + ( ρ n ) ρ n ( )( 1.74) + [( )( 1.74) ] ( )( 1.74) k + n A d 1 k ( ) Figur : Dsign Exampl. (Continud)

32 I r Ir Dsign basd on ACI 440.1R-0 dsign guidlins ( 10)( 1.75) 4 61 in. ( 0.1) (.60)( 1.75) ( 1 0.1) Comput th rdution oiint or dltions using α b 0.50 or FRP bars having th sam bond strngth as stl bars: E β + 1 d α b Es 679 ksi βd ksi I r Ir Dsign basd on rsults rom this rsarh projt ( 10)( 1.75) 4 61 in. ( 0.1) (.60)( 1.75) ( 1 0.1) Comput th rdution oiint or dltions using α b 0.50 or FRP bars having th sam bond strngth as stl bars: E β + 1 d α b Es 679 ksi βd ksi Momnt du to dad load plus liv load: wdl+ LL l M DL+ LL 8 M DL+ LL kip kip ( )( 14 ) t + t t 48.4 kip t 8 Momnt du to dad load plus liv load: wdl+ LL l M DL+ LL 8 M DL+ LL kip kip ( )( 14 ) t + t t 48.4 kip t 8 Craking momnt: M y I r g r t ' 7.5 I h g Craking momnt: M y I r g r t ' 7.5 I h g Figur : Dsign Exampl. (Continud)

33 Dsign basd on ACI 440.1R-0 dsign guidlins 4 ( ) psi 584 in. 1kip 1 t M r 17.7 kip t 16 in lb 1 in. Crakd momnt o inrtia: M r M r ( I ) DL LL d I g I r M β + 1 DL LL M + + DL+ LL ( I ) ( 0.608)( 584) 1 ( 61) DL+ LL I 690 in. ( ) 4 DL+ LL Dsign basd on rsults rom this rsarh projt 4 ( ) psi 584 in. 1kip 1 t M r 17.7 kip t 16 in lb 1 in. Crakd momnt o inrtia: M r M r ( I ) DL LL d I g I r M β + 1 DL LL M + + DL+ LL ( I ) ( 0.608)( 584) 1 ( 61) DL+ LL I 690 in. ( ) 4 DL+ LL Midspan dltion du to dad and liv load: 4 5wDL+ LL l ( yi ) DL+ LL 84 E I ( y ) ( ) DL LL + ( kip kip 4 )( ) ( in. t + t t ) 84 ( 605 ksi)( 695 in. ) t in. i DL+ LL 4 Midspan dltion du to dad and liv load: 4 5wDL+ LL l ( yi ) DL+ LL 84 E I ( y ) ( ) DL+ LL ( kip kip 4 )( ) ( in. t + t t ) 84 ( 605 ksi)( 695 in. ) t in. i DL+ LL 4 Midspan dltions du to dad load alon and liv load alon: wdl ( y i ) ( yi ) DL DL+ LL w DL+ LL Midspan dltions du to dad load alon and liv load alon: wdl ( y i ) ( yi ) DL DL+ LL w DL+ LL Figur : Dsign Exampl. (Continud)

34 4 Dsign basd on ACI 440.1R-0 dsign guidlins kip y 0.69 in. 0.7 in. t ( ) ( ) i DL kip kip t + 1. t w w LL ( y i ) ( yi ) LL DL+ LL DL+ LL kip 1. y 0.69 in. 0.4 in. t ( ) ( ) i LL kip kip t + 1. t Allowabl instantanous liv load dltion: l ( y i ) LL 60 in ( 14 t)( 1 t ) 0.4 in in. 60 < O.K. Long-trm dltion: ξ 1.5 (ACI 18 or a duration o six months) λ 0. 60ξ λ ( ) 75 Comput six-month dltion and ompar to allowabl: y y + λ y LT LT ( i ) LL ( i ) DL ( ) ( ) y 0.4 in in. 0.6 in. Dsign basd on rsults rom this rsarh projt kip y 0.69 in. 0.7 in. t ( ) ( ) i DL kip kip t + 1. t w wdl+ LL y kip in. 0.4 in. LL ( y i ) ( yi ) LL DL+ LL t ( ) ( ) i LL kip kip t + 1. t Allowabl instantanous liv load dltion: l ( y i ) LL 60 in ( 14 t)( 1 t ) 0.4 in. < 0.47 in. O.K. 60 Long-trm dltion du to dad load: Comput initial top ibr strain and urvatur at midspan. Ara o transormd stion in omprssion: A bkd 10.5 in in. 1.9 in. ( )( )( ) First momnt o ara o transormd stion in omprssion about top sura: ( kd ) ( ) ( 0.1 )( 1.75 in. ) B b 10.5 in in. Figur : Dsign Exampl. (Continud)

35 5 Dsign basd on ACI 440.1R-0 dsign guidlins Allowabl long-trm dltion: l y LT 40 in. ( 14 t)( 1 t ) 0.6 in. < 0.70 in. OK 40 Dsign basd on rsults rom this rsarh projt Momnt o inrtia o transormd stion in omprssion about top sura: ( kd ) ( kd ) I b + b 1 ( ) ( 0.1 )( 1.75 in. ) ( ) ( 0.1 )( 1.75 in. ) I 10.5 in in in. I A ' B A + d da ( 1 k ) ( )( ) 48.5 in in. 1.9 in. A 1.9 in. 1.7 in. B ' in. ( 1 ) ' B I db + d ( 1 k ) ( )( ) 98. in in in. B 48.5 in..86 in. 4 ' in. ( 1 ) Momnt du to dad load: wdl l M DL 8 Figur : Dsign Exampl. (Continud)

36 6 Dsign basd on ACI 440.1R-0 dsign guidlins M DL Dsign basd on rsults rom this rsarh projt ( kip )( ) t 14 t 19.0 kip t 8 Initial top ibr strain and urvatur at midspan: ε 1 in. 19 kip t ( )(.86 in. ) 4 ( ) ( )( ) 1 in. ( 1.7 in. )( 19 kip t)( ) 4 ( ) ( )( ) 1t 4 oic 605 ksi 48.5 in. 98.in. 1.9 in. κic 1.0x10 in. 605 ksi 48.5 in. 98.in. 1.9 in. Chk urvatur: κ 1 in. 19 kip t ( ) ( )( ).1x10 in./ in. 1t 4 1 M OK i 1t 4 1 ic 1.0x10 in. 4 EI r 605 ksi 61 in. Chk top ibr strain: 4 1 ε k kd 1.0x10 in in. oic i ( )( )( ) ε oic x in in /. OK Crp oiint at six months: Assum C ult.5. Δ φ( 0.6 ( t τ ) + ( t τ ) t, τ ) C 0. 6 ult D Figur : Dsign Exampl. (Continud)

37 Dsign basd on ACI 440.1R-0 dsign guidlins Dsign basd on rsults rom this rsarh projt 0.6 ( ) + ( ) (.5) Δφ ( 180,14) Choos an aging oiint χ 0.8, as rommndd by Gilbrt and Miklborough: Shrinkag strain at six months: Assum th bam was urd or 7 days. t ( ε sh ) t ( ε sh ) 5 + t ult Assum (ε sh ) ult -70x10-6 ( ) ( 180 7) ε sh x x in in ( ) ( ) /. 7 Obtain an quivalnt imaginary rp loss o prstrssing or at six months. As xplaind in th rp tst rsults stion, th rp strain an b assumd to b indpndnt o strss. Thus, or a bam with a distributd load, th rp strain will b assumd to b onstant ovr th ull lngth o th 14-t span. Th rp strain at six months o 4x10-6 inh/inh rom spimn V1-5-b o th rp tst will b usd. Figur : Dsign Exampl. (Continud)

38 Dsign basd on ACI 440.1R-0 dsign guidlins Dsign basd on rsults rom this rsarh projt Thus, th quivalnt imaginary rp loss o prstrssing or is: 6 in. F ΔP ε E A 4x ksi.60 in..8 kip 1 in. Ag-adjustd tiv modulus: E E ( t, τ ) 1+ χδφ( t, τ ) 605 ksi E ( t, τ ) 1591 ksi ( )( ) ( )( ) 8 Total rstraining ors at midspan: δ N E oic ic [ Δφ( Aε oic + Bκ ic ) + ε sh A ] + m j ( )( ) ( )( ) A ε + B κ 1.9 in..1x in. 1.0x10 in. A ε oic + B κ ic 5.0x10 in. ( ) ( A ) ( 4 )( oic + B ic + sha x10 in x in. ) ( A + B ) + A 0.07 in. Δφ ε κ ε Δφ ε κ ε oic ic sh ( ) δ N 1579 ksi 0.07 in..8 kip δ N 9. kip F j Figur : Dsign Exampl. (Continud)

39 Dsign basd on ACI 440.1R-0 dsign guidlins δ M Dsign basd on rsults rom this rsarh projt E oic ic [ Δφ( Bε oi + I κ i ) + ε sh B ] + m F d j j j ( )( ) ( )( ) B ε + I κ 48.5 in..1x in. 1.0x10 in. B ε oic + I κ ic 5.11x10 in. ( ) ( B ) ( 4 )( oic + I ic + shb x10 in x in. ) ( B + I ) + B in. Δφ ε κ ε Δφ ε κ ε oic ic sh 1t ( )( )( 1 in. ) 1t ( )( 1 in. ) Fd.8 kip 1.75 in. 4.8 kip t δ M 1579 ksi in. 4.8 kip t δ M 0.57 kip t 9 Proprtis o ag-adjustd transormd stion: Ara o ag-adjustd transormd stion: A bkd + n A E 679 ksi n.98 E 1579 ksi ( )( )( ) ( ) A 10.5 in in in. 4. in. Figur : Dsign Exampl. (Continud)

40 Dsign basd on ACI 440.1R-0 dsign guidlins Dsign basd on rsults rom this rsarh projt First momnt o ara o ag-adjustd transormd stion about top o sura: ( kd ) B b + n A d ( ) ( 0.1 )( 1.75 in. ) B 10.5 in (.6 in. )( 1.75 in. ) 191 in. 0 Momnt o inrtia o transormd stion in omprssion about top o sura: ( kd ) ( kd ) I b + b + n A d 1 ( ) ( 0.1 )( 1.75 in. ) ( ) ( 0.1 )( 1.75 in. ) I 10.5 in in (.6 in. )( 1.75 in. ) I 054 in. 4 A ' A B da + d ( 1 k ) ( )( ) 191 in in. 4. in. A 4. in in. ' in. ( 1 ) Figur : Dsign Exampl. (Continud)

41 1 Dsign basd on ACI 440.1R-0 dsign guidlins B ' Dsign basd on rsults rom this rsarh projt I db B + d 1 k ( ) ( )( ) 054 in in. 191 in. B 191 in. 146 in. 4 ' in. ( 1 ) Tim-dpndnt inrmnts o urvatur and top sura strain at midspan: ' δmb δni Δε oc E B I A Δε Δε ( ) 1 in. 4 ( 0.57 kip t)( 1t )( 146 in. ) ( 9.4 kip)( 054 in. ) ksi ( 191in. ) ( 054 in. )( 4. in. ) oc oc 1.01x10 B δn A Δκ C E Δκ Δκ ε oc ' δ ( B I A ) M 1 in. ( 191 in. )( 9.4 kip) ( 11.6 in. )( 0.57 kip t)( 1t ) 1579 ksi ( 191in. ) ( 054 in. )( 4.in. ) C C 9.9x10 ε + Δε oic 5 oc 1 in. 1.1x10 in./ in. Figur : Dsign Exampl. (Continud)

42 Dsign basd on ACI 440.1R-0 dsign guidlins Dsign basd on rsults rom this rsarh projt Final urvatur and top sura strain at midspan: 4 1 κ C κ ic + Δκ 1.96x10 in. Initial top ibr strain and urvatur at lt support: ' M i B N i I ε oil 0 sin Mi0 and Ni 0 E B I A ( ) ' B N A M κ il 0 sin Mi0 and Ni 0 E i i ( B I A ) Total rstraining ors at lt support: δn E δ N E [ Δφ( Aε oil + Bκ il ) + ε sh A ] + m ( ε sh A ) + j 1 F j 4 ( )( ) δ N 1579 ksi 6.07x10 1.9in..8 kip 6.8 kip m j 1 F j δ M δ M E E [ Δφ( Bε oil + I κ il ) + ε sh B ] + m ( ε shb ) + j 1 F d j j m j 1 F d 4 1t ( )( ) ( 1 in. ) δ M 1579 ksi 6.07 x in. 4.8 kip t δ M 0.50 kip t j j Figur : Dsign Exampl. (Continud)

43 Dsign basd on ACI 440.1R-0 dsign guidlins Dsign basd on rsults rom this rsarh projt Tim-dpndnt inrmnts o urvatur and top sura strain: ' δmb δni Δε ol E B I A Δε ( ) 1 in. 4 ( 0.50 kip t)( 1t )( 146 in. ) ( 6.8 kip)( 054 in. ) ksi ( 191in. ) ( 054 in. )( 4.in. ) ol Δε ol 7.0x10 4 B δn A Δκ L Δκ ' δ M E ( B I A ) 1 in. ( 191 in. )( 6.8 kip) ( 11.6 in. )( 0.50 kip t)( 1t ) ksi ( 191in. ) ( 054 in. )( 4.in. ) L Δκ 6.50x10 L 5 1 in. Final urvatur and top sura strain at lt support: 4 ε ε + Δε 7.0x10 in./ in. κ ol oil ol 5 L κ il + Δκ L 6.50x10 in Initial top ibr strain and urvatur at right support: ε 0, κ 0 oir ir. 1 Figur : Dsign Exampl. (Continud)

44 Dsign basd on ACI 440.1R-0 dsign guidlins Dsign basd on rsults rom this rsarh projt Final urvatur and top sura strain at lt support: 4 ε 7.0x10 in./ in. κ R or x10 in. 1 Comput midspan dltion at six months du to dad load: L ( ylt ) ( κ L + 10κ C + κ R ) DL 96 ( ) 1 in. ( 14 t)( ) ylt 6.50x10 in x x10 in. DL 96 ( y ) LT DL 0.61in. ( ( ) ) 1t Total six-month dltion at midspan: y y + y LT LT ( i ) ( LT ) DL LL y 0.41 in in. 1.0 in. Allowabl long-trm dltion: l y LT 40 in. ( 14 t)( 1 t ) 1.0 in. > 0.70 in. N.G. 40 Bor rdsigning th stion, hk th maximum rak width. Figur : Dsign Exampl. (Continud)

45 5 Dsign basd on ACI 440.1R-0 dsign guidlins 6. Chk th maximum rak width. Comput th strss lvl in th FRP bars undr dad load plus liv load (srvi onditions): M DL+ LL A d 1 k 1 in kip t 1t 17.5 ksi 0.1 (.60 in. ) 1.75 in. 1 Find th tiv tnsion ara o onrt: h kd β d kd 16 in. 0.1( 1.75 in. ) β in in. ( ) 1 d ovr + stirrup siz + db 1 d 1.5 in ( 0.74 in. ).5 in. ( h d) b A No. bars ( )( ) 16 in in in. A 7.86 in. 6 Dsign basd on rsults rom this rsarh projt 6. Chk th maximum rak width. Comput th strss lvl in th FRP bars undr dad load plus liv load (srvi onditions): M DL+ LL A d 1 k 1 in kip t 1t 17.5 ksi 0.1 (.60 in. ) 1.75 in. 1 Find th tiv tnsion ara o onrt: h kd β d kd 16 in. 0.1( 1.75 in. ) β in in. ( ) 1 d ovr + stirrup siz + db 1 d 1.5 in ( 0.74 in. ).5 in. ( h d) b A No. bars ( )( ) 16 in in in. A 7.86 in. 6 Figur : Dsign Exampl. (Continud)

46 Dsign basd on ACI 440.1R-0 dsign guidlins Comput th maximum rak width using ACI 440.1R-0 Equation 8-9b: E s w 0.076β d A E 9000 w ksi.5 in in. 679 w 19 mils < 0 mils OK ( ) ( ) ( )( ) Dsign basd on rsults rom this rsarh projt Comput th maximum rak width using Equation 81 rom this rsarh: W 0. β d A max Wmax ksi.5 in in. 679 W mils > 0 mils N.G. Rdsign th bam. max ( ) ( ) ( )( ) 6 Comput th maximum rak width using ACI 440.1R-0 Equation 8-9, using th rommndd valu o kb 1.: 00 w βk b d A E 00 w ( 1.1)( 1.)( 17.5 ksi) (.5 in. )( 7.86 in. ) 679 w mils > 0 mils N.G. 5a. Chk th short-and long-trm dltions o th bam. 5a. Chk th short-and long-trm dltions o th bam. Th bam is adquat or short-trm and long-trm dltions. Try h 19 inhs. A ρ bd.60 in. ρ < 1.4ρb φ in.( in.) Figur : Dsign Exampl. (Continud)

47 Dsign basd on ACI 440.1R-0 dsign guidlins Dsign basd on rsults rom this rsarh projt Momnt apaity: φ M 11.7 kip t M 77.7 kip t OK n u Liv load dltion: y 0. in. < 0.47 in. OK ( ) i LL 7 6a. Chk th maximum rak width. Th bam is adquat pr ACI Equation 8-9b. Try h 19 inhs. Comput th maximum rak width using ACI 440.1R-0 Equation 8-9, using th rommndd valu o kb 1.: w 18.6 mils < 0 mils OK 7. Chk th rp ruptur strss limit. Momnt du to sustaind load: M M S M DL S ( ) kip t 14 t 19.8 kip t 8 Total long-trm dltion: ( ) LT l y 0.67 in in. OK 40 6a. Chk th maximum rak width. Comput th maximum rak width using Equation 81 rom this rsarh: W 18.4 mils < 0 mils OK max 7. Chk th rp ruptur strss limit. Momnt du to sustaind load: M M S M DL S ( ) kip t 14 t 19.8 kip t 8 Figur : Dsign Exampl. (Continud)

48 8 Dsign basd on ACI 440.1R-0 dsign guidlins Sustaind strss in th FRP bars: M S, S k A d 1 1 in kip t 1t 5.85 ksi 0.0 (.6 in. ) in. 1 Chk th strss limit or GFRP bars: 0. 0, S u 5.85 ksi 0.0 ( 6 ksi) 1.4 ksi O.K. 8. Comput th basi dvlopmnt lngth. Us ACI Equation 11-7: db u ( 0.74 in. )( 6000 psi) lb 17in Comput additional dltions du to yli loading. ACI 440.1R-0 dos not aount or dltions du to yli loading. Dsign basd on rsults rom this rsarh projt Sustaind strss in th FRP bars: M S, S k A d 1 1 in kip t 1t 5.85 ksi 0.0 (.6 in. ) in. 1 Chk th strss limit or GFRP bars: 0. 0, S u 5.85 ksi 0.0 ( 6 ksi) 1.4 ksi O.K. 8. Comput th basi dvlopmnt lngth. Us Equation 90 rom this rsarh: dbu,av ( 0.74 in. )( psi) lb 6.4 in Comput additional dltions du to yli loading. Assum th yli loading will b du to liv load alon. Thus, us th slop o Equation 84 rom this rsarh, and us th initial dltion du to dad load and liv load. Figur : Dsign Exampl. (Continud)

49 Dsign basd on ACI 440.1R-0 dsign guidlins Dsign basd on rsults rom this rsarh projt Initial dltion du to dad load and liv load: 4 5wDL+ LL l ( yi ) DL+ LL 84 E I ( ) ( ) DL+ LL ( kip kip 4 )( ) ( in. t + t t ) 84( 605 ksi)( 199 in. ) t 1 y 0.15 in in. i DL+ LL 4 ( y ) i DL+ LL 0.7 in. Lowr bound bam dtion du to million yls o appliation o liv load: 9 y in.ln( n ) in. y in.ln( ) in in. Figur : Dsign Exampl. (Continud)

50 As a rsult o this rviw, th rsarhrs proposd th ollowing hangs to th ACI 440.1R-0 dsign and onstrution guidlins. A rvaluation o th nvironmntal rdution ators is proposd, sin this rsarh showd that thy may not b onsrvativ. Equation, prsntd arlir, is proposd to rpla Equation 8, 9a in th ACI 440.1R-0 dsign and onstrution guid (00). This rsarh also proposs that th dltions o GFRP-rinord onrt lmnts indud by yli loading also b aountd or in th ACI 440.1R-0 dsign and onstrution guidlins. Crp should b aountd or as shown in Rport (Trjo t al. 00). Equation 9 o this rport is proposd to rpla Equation 11-7 o th ACI 440.1R-0 dsign and onstrution guidlins. Finally, th minimum ovr o 1 bar diamtr rommndd by th ACI 440.1R-0 dsign and onstrution guidlins annot b vriid or adquay using this rsarh. Howvr, this rsarh showd that a ovr o 1. bar diamtrs has bn shown by this rsarh to hav no raking problms du to thrmal xpansion. 40

51 III. PROPOSED REVISIONS TO THE AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS This stion prsnts a rviw o th 1998 AASHTO LRFD bridg dsign spiiations (1998) and rommnds hangs basd on th rsults o this and othr rsarh rlatd to th us o non-prstrssd GFRP bars to rinor onrt struturs. This stion prsnts a bri introdution ollowd by a dsription o th AASHTO stions that may nd to b modiid to inlud th dsign o onrt lmnts rinord with FRP bars. Th stions o th AASHTO spiiations that do not nd to b modiid ar not listd in this stion. Th 1998 AASHTO LRFD bridg dsign spiiations do not inlud rommndations or th dsign o onrt struturs rinord with GFRP bars. Baus th rsults obtaind by this rsarh and by th studis rrnd ar limitd to th onditions and xposurs valuatd in this rsarh, xtrm ar should b takn whn dsigning GFRP-rinord onrt lmnts that will b subjtd to dirnt onditions. It should b notd that ths rommndations ar proposd basd on th rsarh to dat and in most ass mor work is ndd bor implmnting suh modiiations. A rviw o th appliabl stions is prsntd nxt. Not that th stion numbrs listd blow ar th stion numbrs rom th 1998 AASHTO LRFD bridg dsign spiiations. PROPOSED REVISIONS 1. Add to Stion 1.. Dutility This stion o th od rquirs th bridg to dvlop signiiant and visibl inlasti dormations at th strngth and xtrm vnt limit stats. Sin GFRP bars xhibit linarly lasti bhavior up to ailur, GFRP-rinord onrt lmnts do not xhibit signiiant dutility. Naaman and Jong (1995) indiatd that although FRPrinord onrt bams may dorm onsidrably bor ailur, thy lastially stor most o th nrgy imposd on thm during loading. Thus, sin inlasti dormations 41

52 ar rquird by th od, ithr GFRP bars should not b usd or GFRP bars should b usd in ombination with othr systms or matrials to provid dutility. Altrnativly, th od may dvlop non-dutil bhavior rquirmnts or GFRP-rinord onrt lmnts.. Add to Stion Matrials Th dgradation o GFRP rinormnt should b aountd or in dsign. Th tnsil strngth o GFRP bars an dgrad in th onrt. Th durability o FRPrinord onrt struturs an b atd by svral nvironmntal ators suh as: aids, alkalis, high tmpraturs, ultraviolt radiation, organi solvnts, and oxygn or ozon (Bakht t al. 000). Th bond strngth btwn GFRP bars and onrt an dgrad with tim in high-tmpratur moist onditions.. Add to Stion.10.1 Gnral Th at that FRP-rinord onrt lmnts ar non-dutil should b onsidrd whn prorming a sismi dsign. 4. Noti or Stion 4.6. Approximat Mthods o Analysis This stion may rquir modiiations baus FRP-rinord onrt lmnts with a givn amount and distribution o rinormnt and a givn gomtry hav lowr stinss than stl-rinord onrt lmnts having th sam gomtry and amount and oniguration o rinormnt. 5. Noti or Stion 5 Conrt Struturs Th ACI 440.1R-0 (00) dsign and onstrution guidlins should b adoptd or this stion. Howvr, spial ar must b takn to nsur that ths quations and ators apply to th onditions at th atual struturs loation baus it has bn dtrmind that nvironmntal onditions do at th prorman o GFRP rinoring bars. Spial onsidration should b givn to th substions addrssd in th ollowing proposd rvisions. 4

53 6. Add to Stion 5.4 Matrial Proprtis Considration should b givn in this stion to th matrial proprtis o GFRP bars suh as tnsil strngth, aounting or nvironmntal rdution ators, as alrady disussd in th ACI 440.1R-0 dsign and onstrution guidlins, oiint o thrmal xpansion o th FRP bars, rp o FRP bars, dltions du to yli loading, and dtrioration o bond strngth btwn GFRP bars and onrt. A dsription o th durability and rativity o ibrs and rsins to dirnt nvironmntal onditions givn in th Canadian Bridg Dsign od provisions or ibr-rinord struturs ould b inludd in this stion (Bakht t al. 000). A summary o th dltrious ts o svral nvironmnts on ibrs and matris as dsribd by Bakht t al. (000) is givn nxt: Watr: Polymri ibrs and matris absorb moistur. Moistur absorption sotns th polymrs. Thr ar not suiint data or th rat o dtrioration o arbon and glass ibrs. Wak aids: Bridgs in industrializd aras may b xposd to wak aids rom aid rain and arbonization, with ph valus btwn 4 and 7. Wak aids an attak glass ibrs and polystr matris. Strong aids: Aidntal spillag may aus strong aids to om in ontat with bridg omponnts. Strong aids an attak glass ibrs, aramid ibrs, and polystr and poxy matris. Wak alkalis: Conrt ontaining pozzolans an hav ph valus btwn 7 and 10. Wak alkalis suh as ths matrials an attak glass ibrs and polystr matris. Strong alkalis: Typial Portland mnt onrts hav ph valus gratr than 10 and an aus dgradation o glass ibrs. Strong alkalis an attak glass ibrs, aramid ibrs, and polystr matris. High tmpraturs: Carbon and glass ibrs ar rsistant to high tmpraturs. Howvr, high tmpraturs advrsly at aramid ibrs and polymri matris. 4

54 Ultraviolt radiation: Carbon and glass ibrs ar rsistant to ultraviolt radiation. Howvr, ultraviolt radiation advrsly ats aramid ibrs and polymri matris. 7. Mov Stion Prstrssing Stl to Stion Mov Stion Posttnsioning Anhorags and Couplrs to Stion Mov Stion Duts to Stion Add Stion FRP Rinormnt 11. Add Stion Gnral Th dsign tnsil strngth o GFRP bars should b takn rom th ACI 440.1R- 0 dsign and onstrution guidlins as shown prviously in Equation 1: C u E * u 1. Add Stion Modulus o Elastiity Th modulus o lastiity o FRP bars should b th avrag valu rportd rom propr tsting or by th manuaturr. 1. Add to Stion Rinoring Bars Th rsults o th yli load tsts ondutd in this rsarh indiat that th lxural strngth o GFRP-rinord onrt bams show no signiiant dgradation atr th appliation o 4 and 5 million yls o an altrnating load with a GFRP bar strss rang o 18.9 ksi. Th atigu apaity o FRP bars to b usd in a bridg should b validatd by urthr tsts. 44

55 14. Add Stion FRP Constrution Th rsistan ators rommndd by th ACI 440.1R-0 dsign and onstrution guidlins should b usd in this stion. Th rsistan ators or lxur ar: φ 0.50 or ρ ρ b φ ρ ρ b or ρ < ρ b < 1.4ρ b (1) φ 0.70 or ρ 1.4ρ b Th rsistan ator or shar should b th sam as th ator usd in th ACI 18 (000) building od (φ 0.85). 15. Add Stion FRP-Rinord Conrt Elmnts Th quations or lxural rsistan givn in th ACI 440.1R-0 dsign and onstrution guidlins should b usd in this stion. Th rinormnt ratio ( ρ ) and th baland rinormnt ratio ( ρ ) or GFRP-rinord stions an b omputd with Equations 1 and 14, rsptivly: b A ρ (1) bd ρ b ' E ε u 0.85β1 (14) E ε + whr, A Ara o FRP rinormnt (inh ), a Dpth o quivalnt rtangular strss blok (inh), b Width o stion (inh), d Etiv dpth o th stion (inh), ε u Ultimat strain in onrt, β 1 Fator takn as 0.85 or valus o up to and inluding 4 ksi. Abov 4 ksi, th atord is rdud linarly at a rat o 0.05 or ah 1 ksi in xss o 4 ksi, but should not b smallr than 0.65, u u u 45

56 u Dsign tnsil strngth o FRP rinormnt (ksi), Dsign omprssiv strngth o onrt (ksi), E Modulus o lastiity o FRP bars (ksi). Whn th rinormnt ratio is blow th baland ratio, FRP ruptur is th ailur mod; othrwis, onrt rushing is th ailur mod. Th ACI 440.1R-0 dsign and onstrution guidlins rommnd th ollowing quations to omput th nominal lxural apaity whn th rinormnt ratio is gratr than th baland ratio: whr, a M n A d (15) A a ' 0.85 b (16) ( E ε ) ' 0.85β E E u 1 + εu 0.5 εu u 4 ρ M n Nominal lxural apaity (kip.inh), Strss in th FRP rinormnt (ksi). (17) Whn th rinormnt ratio is smallr than th baland ratio, th ACI 440.1R- 0 dsign and onstrution guidlins rommnd th ollowing quation to omput th nominal lxural apaity: M b n 0.8A ε u ε u + ε u u β d Whr ε u is th ultimat strain in th GFRP rinormnt and all othr trms wr prviously dind. d 1 b (18) (19) 46

57 16. Add to Stion Minimum Rinormnt For FRP-rinord onrt lmnts in whih ailur is ontrolld by FRP ruptur, th minimum ara o FRP rinormnt should b as rommndd by th ACI 440.1R-0 dsign and onstrution guidlins: A ' bwd bwd (0), min u This rquirmnt is intndd to prvnt lxural ailur upon onrt raking. u 17. Add to Stion Control o Craking by Distribution o Rinormnt This stion should us th allowabl rak width or FRP-rinord onrt lmnts as rommndd by th ACI 440.1R-0 dsign and onstrution guidlins. Th allowabl maximum rak widths ar 0.08 inhs or intrior xposur and 0.00 inhs or xtrior xposur. Maximum rak widths an b stimatd using th ollowing quation, validatd in this projt and prsntd arlir as Equation : W max 0. 09β d A 18. Add to Stion Momnt Rdistribution Following th ACI 440.1R-0 dsign and onstrution guidlins, sin GFRPrinord onrt lmnts xhibit linar lasti bhavior up to ailur, momnt rdistribution should not b onsidrd or GFRP-rinord onrt. 19. Add to Stion Dltion and Cambr Dltion and ambr o GFRP-rinord onrt lmnts should onsidr GFRP rp. Equations 8-1a and 8-1b as rommndd by th ACI 440.1R-0 dsign and onstrution guidlins to omput instantanous dltions should b usd: I M M r a M r β I g + 1 I r I g M (1) a 47

58 E β α + 1 () Es whr, I r rakd momnt o inrtia o th stion (inh 4 ), I g Gross momnt o inrtia o th stion (inh 4 ), and all othr trms hav bn dind prviously. Th long-trm dltions an b omputd using Equation 8-14, providd by th ACI 440.1R-0 dsign and onstrution guidlins and shown prviously as Equation 6: Δ + 0.6ξ Δ ( p sh ) ( i ) sus Altrnativly, th hang in urvatur du to long-trm loading an b omputd using th ollowing quation, shown arlir as Equation 7: B δn A Δκ E ' δ ( B A I ) and th long-trm dltions an b omputd by substituting Equation 7 into Equation 8: y C L A M ( κ + κ + κ ) Cyli loading o onrt bam tsts shows that dltions du to yli loading an inras by 78 prnt du to yli loading and should b inludd in th omputation o dltions du to liv load. C B Th slop o Equation 5 an b usd to omput th lowr bound dltion inrmnts du to th appliation o yli load: y ln( n)

59 0. Add to Stion Minimum Transvrs Rinormnt Th rquirmnts or minimum transvrs rinormnt providd by th ACI 440.1R-0 dsign and onstrution guidlins should b adoptd in this stion. Th minimum transvrs rinormnt or FRP-rinord onrt stions is: A 50b s w v, min () v whr, A v,min Minimum ara o transvrs FRP rinormnt (inh ), b w Width o stion (inh), s Spaing o stirrups (inh), v Strss lvl in th FRP shar rinormnt at ultimat (ksi). Aording to th ACI 440.1R-0 dsign and onstrution guidlins, th strss lvl in th FRP shar rinormnt at ultimat should b limitd to th ollowing valu to avoid ailur at th bnt portion o th FRP stirrup: v 0. 00E (4) whr b is th strngth o a bnt portion o an FRP stirrup (ksi). b 1. Add to Stion Nominal Shar Rsistan Th nutral axis dpth o rakd FRP-rinord onrt stions is smallr than that or stl-rinord onrt lmnts du to th lowr stinss o FRP bars whn ompard to stl bars (ACI 000). Thus, th ontribution to shar strngth by aggrgat intrlok, dowl ation, and shar o omprssd onrt ar lowr or FRPrinord onrt mmbrs than or stl-rinord onrt mmbrs. This stion should adopt th rommndations o th ACI 440.1R-0 dsign and onstrution guidlins or shar dsign o FRP-rinord onrt mmbrs. Th ACI 440.1R-0 dsign and onstrution guid rommndations or th shar or takn by th onrt should b usd: V, ρ E V (5) 90β 1 ' 49

60 whr th trms ar as dind bor and V is th nominal shar or providd by th onrt or stl-rinord onrt mmbrs as givn in th ACI 18 od (000). Th valu o V, should not b largr than V. Th rquird spaing and ara o shar rinormnt whn stirrups ar usd prpndiular to th mmbr ar: whr th trms hav bn dind bor and, A v Ara o shar rinormnt (inh ), V u Fatord shar or at stion (kips). A s v ( V V ) u φ, (6) φ d v. Add to Stion Standard Hooks Th rommndation o ACI 440.1R-0 dsign and onstrution guidlins or a minimum tail lngth o 1 bar diamtrs should b usd in this stion.. Add to Stion Minimum Bnd Diamtrs Th minimum ratio o radius o bnd to bar diamtr o thr or FRP stirrups, as rommndd by th ACI 440.1R-0 dsign and onstrution guidlins, should b onsidrd in FRP-rinord onrt lmnts. 4. Add to Stion Transvrs Rinormnt or Flxural Mmbrs A maximum spaing or transvrs rinormnt o d/ or 4 inhs, as rommndd by th ACI 440.1R-0 dsign and onstrution guidlins, should b onsidrd in this stion. 5. Add to Stion Shrinkag and Tmpratur Rinormnt Th ACI 440.1R-0 dsign and onstrution guidlins rommndd minimum rinormnt ratio or tmpratur and shrinkag ρ,ts should b usd in this stion (but nd not b mor than ): 50

61 60,000 Es ρ, ts (7) E u 6. Noti or Stion Provisions or Sismi Dsign Sin GFRP rinormnt is non-dutil, provisions should b takn in th dsign o GFRP-rinord onrt lmnts whr dutility is rquird. 7. Add to Stion Tnsion Dvlopmnt Lngth This rsarh rommnds that th basi dvlopmnt lngth o GFRP-rinord onrt lmnts b omputd with th ollowing quation, shown arlir as Equation 11: db l b 700 u,av 8. Add to Stion Modiiation Fators that Inras l d Th ACI 440.1R-0 dsign and onstrution guidlins rommnd a modiiation ator o 1. or top bars to obtain th dvlopmnt lngth o an FRP bar (l d ). 9. Add to Stion Basi Hook Dvlopmnt Lngth Th rommndd dvlopmnt lngth or a bnt bar providd by th ACI 440.1R-0 dsign and onstrution guidlins should b usd in this stion. Th dvlopmnt lngth or hookd bars is dtrmind as ollows: d b lbh 000 or ' u 75,000 psi d < < (8) u b lbh or 75,000 psi ' u 150,000 psi 7.5 d b lbh 4000 or ' u 150,000 psi 51

62 d b or 9 inhs. Th dvlopmnt lngth omputd with Equation 8 should not b lss than 1 0. Add to Stion Lap Splis in Tnsion Thr is limitd rsarh in this ara. Howvr, th ACI 440.1R-0 dsign and onstrution guidlins rommnd using valus o 1. l d or lass A and 1.6 l d or lass C splis (as dind by AASHTO). Sin th valu o 1.7 l d or lass C spli rommndd by AASHTO is mor onsrvativ, it is advisabl to us that valu to omput th dvlopmnt lngth o splid FRP bars. 1. Add to Stion 5.1 Durability This stion should giv spial onsidration to th durability o GFRP rinormnt. Rr to th nw proposd stion 5.4 Matrial Proprtis (rommndd by this rsarh to b addd to th AASHTO LRFD spiiations) or a bri dsription o nvironmntal ts on GFRP bars. A summary o th dltrious ts o svral nvironmnts on ibrs and matris as dsribd prviously is rpatd nxt: Watr: Moistur absorption sotns th polymrs. Thr ar not suiint data or th rat o dtrioration o arbon and glass ibrs. Wak aids: Wak aids an attak glass ibrs and polystr matris. Strong aids: Strong aids an attak glass ibrs, aramid ibrs, and polystr and poxy matris. Wak alkalis: Wak alkalis an attak glass ibrs and polystr matris. Strong alkalis: Strong alkalis an attak glass ibrs, aramid ibrs, and polystr matris. High tmpraturs: Carbon and glass ibrs ar rsistant to high tmpraturs. Nvrthlss, high tmpraturs advrsly at aramid ibrs and polymri matris. 5

63 Ultraviolt radiation: Carbon and glass ibrs ar rsistant to ultraviolt radiation. Howvr, ultraviolt radiation advrsly ats aramid ibrs and polymri matris.. Add to Stion 5.1. Conrt Covr This stion o th od spiis a minimum ovr or xtrior xposur o inhs. Th rommndd ovrs should onsidr th at that a 1-inh ovr or a onrt dk with omprssiv strngth o approximatly 5.88 ksi and a 0.75-inh diamtr bar dos not aus raking du to thrmal xpansion. This implis that, aording to this rsarh, a ovr o 1. bar diamtrs is adquat to avoid raking du to thrmal xpansion or typial onditions nountrd by bridg suprstruturs. Th -inh ovr should b adquat or lmnts rinord with 0.75-inh and smallr diamtr bars. Th ovr dpth dsign o lmnts xposd to dirt solar radiation rinord with bar diamtrs largr than 0.75 inh should b supportd by tsts. 5

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65 IV. RECOMMENDED CONSTRUCTION GUIDELINES FOR THE USE OF GFRP REINFORCEMENT Constrution using GFRP bars or rinormnt in onrt appliations is similar to onstrution using stl rinormnt with som modiiations. Unlik onvntional stl rinormnt, GFRP rinoring bars typially do not xhibit individually lar markings that idntiy th manuaturr, bar typ, or bar siz. This is lak o inormation typially a rsult o th manuaturing pross. Th ACI 440.1R-0 dsign and onstrution guidlins (00) rommnd that ah produr labl th solid bars or shipping ontainr/pakaging, or both, with a symbol idntiying th manuaturr (XXX), typ o ibr and nominal siz (G or glass and numbr or nominal bar siz,.g., G#4), strngth grad o th bar (.g., F90 to indiat that th guarantd tnsil strngth, * u, is gratr than 90 ksi), and modulus grad (.g., E5.5, indiating that th modulus o lastiity is at last 5,500 ksi). Bar sizs ar th sam as thos listd in A615/A615M (004), Standard Spiiation or Dormd and Plain Billt-Stl Bars or Conrt Rinormnt. Although bnding GFRP bars is possibl, du to th signiiant rdution in strngth apaity ausd by bnding, most dsigns spiy straight bars. Straight GFRP bars ar typially ordrd idntiying lngth, guarantd tnsil strngth, ibr typ, diamtr, and modulus o lastiity. Signiiant dirns btwn unoatd stl and GFRP rinoring bars aris in handling and storag. GFRP bars should b handld in suh ways as to liminat or minimiz sura damag, and storag onditions or GFRP bars should b ontrolld. Th ACI 440.1R-0 dsign and onstrution guidlins rommnd th ollowing or GFRP bars: handl with work glovs; do not stor on ground; xposur to high tmpraturs, ultraviolt rays, and hmial substans should b avoidd; lan GFRP bar suras by wiping th bars with solvnts i ontaminatd; i nssary, us a spradr bar or liting; and 55

66 i nssary, ut bars with high-spd grindr or in-blad saw (bars should nvr b shard). Th ACI dsign and onstrution guidlins provid urthr inormation and th radr is dirtd to this doumnt i urthr inormation is ndd. Ths pratis should prsrv th intgrity o th GFRP bars. In addition to handling and storag ritria or GFRP bars, guidan on th plamnt o GFRP is ndd. GFRP bars an b plad in similar mannrs as that o stl rinoring bars with th ollowing additions and/or xptions usul (ACI 440.1R-0 00): rquirmnts or hair plamnt should b inludd in projt spiiations; plasti or non-orrosiv hairs ar prrrd; rquirmnts or suring GFRP bars should b inludd in spiiations to prvnt movmnt o GFRP bars during onrt plamnt; sit bnding o thrmost GFRP bars is not allowd; and lapping o bars is nssary, and inormation on lngth o lap should b inludd in th spiiations. Figurs and 4 show GFRP rbar tying and hair plamnt and typial spaing or th Sirrita d las Cruz bridg onstrution outsid o Amarillo, Txas. It an b sn that th GFRP bars wr tid with oatd wirs (Figur ) and typial hair spaing was approximatly t. Atual hair spaing is dpndnt on bar typ, ti rquirmnts, and othr paramtrs. Figur. Tying o GFRP Bars. Figur 4. Chair Plamnt or GFRP Rinormnt. 56