Intermediate crack-induced debonding is often a dominant failure mode in fiber-reinforced polymer (FRP)-strengthened reinforced concrete (RC) beams in flexure. It has been extensively studied for RC beams externally strengthened with unstressed FRP laminates. However, very little work has been done on FRP debonding for RC beams strengthened with prestressed FRP. This article presents a sectional analysis model for predicting the flexural capacity of RC beams strengthened with prestressed FRP laminates with due consideration of different failure modes. The focus is placed on the effective strain in the prestressed FRP at the ultimate states of intermediate crack-induced debonding or rupture of debonded FRP. Through back-calculation analysis of 51 RC beams strengthened with post-tensioned FRP laminates, a model for predicting the effective strain of prestressed FRP for ultimate strength prediction based upon sectional analyses was developed and validated through comparisons with test results.
El-HachaRWightRGGreenMF. Prestressed fibre-reinforced polymer laminates for strengthening structures. Progr Struct Eng Mater2001; 3(2): 111–121.
3.
QuantrillRJHollawayLC. The flexural rehabilitation of reinforced concrete beams by the use of prestressed advanced composite plates. Compos Sci Technol1998; 58(8): 1259–1275.
4.
AbhijitMGopalLR. Performance of reinforced concrete beams externally prestressed with fiber composites. Construct Build Mater2009; 23(2): 822–828.
5.
DiabHWuZIwashitaK. Short and long-term bond performance of prestressed FRP sheet anchorages. Eng Struct2009; 31(5): 1241–1249.
6.
TriantafillouTCDeskovicNDeuringM. Strengthening of concrete structures with prestressed fiber reinforced plastic sheets. ACI Struct J1992; 89(3): 235–244.
7.
MeierU. Strengthening of structures using carbon fibre/epoxy composites. Construct Build Mater1995; 9(6): 341–351.
8.
GardenHNHollawayLC. An experimental study of the failure modes of reinforced concrete beams strengthened with prestressed carbon composite plates. Composites: Part B1998; 29(4): 411–424.
9.
Yu P, Silva PF and Nanni A. Flexural performance of RC beams strengthened with prestressed CFRP sheets. In: Domenico B, Giuseppe S and Ramnath NS (eds) Proceedings of the international conference composites in constructions, University of Calabria, Italy, 2003.
10.
WooSKNamJWKimJH. Suggestion of flexural capacity evaluation and prediction of prestressed CFRP strengthened design. Eng Struct2008; 30(12): 3751–3763.
11.
YangDSParkSKNealeKW. Flexural behaviour of reinforced concrete beams strengthened with prestressed carbon composites. Compos Struct2009; 88(4): 497–508.
12.
XueWTanYZengL. Flexural response predictions of reinforced concrete beams strengthened with prestressed CFRP plates. Compos Struct2010; 92(3): 612–622.
13.
Shang SP, Zou, XWP, Peng H, et al. Avoiding de-bonding in FRP strengthened reinforced concrete beams using prestressing techniques. In: Chen and Teng (eds) Proceedings of the international symposium on bond behavior of FRP in structures, Hong Kong, 2005, pp. 321–327.
14.
El-HachaRGreenMFWightRG. Innovative system for prestressing FRP sheets. ACI Struct J2003; 100(3): 305–313.
15.
KimYJGreenMFWightRG. Flexural behavior of reinforced and prestressed concrete beams including strengthening with prestress carbon fibre reinforced polymer sheets: application of a fracture mechanics method. Can J Civil Eng2007; 34(5): 664–677.
16.
PellegrinoCModenaC. Flexural strengthening of real-scale RC and PRC beams with end-anchored pretensioned FRP laminates. ACI Struct J2009; 106(3): 319–328.
17.
WangWWDaiJGHarriesKA. Prestress losses and flexural behavior of reinforced concrete beams strengthened with post-tensioned CFRP sheets. J Compos Construct2012; 16(2): 207–216.
18.
El-HachaRWightRGGreenMF. Prestressed carbon fiber reinforced polymer sheets for strengthening concrete beams at room and low temperatures. J Compos Construct2004; 8(1): 3–13.
19.
KimYJ. Bond and short-term prestress losses of prestressed composites for strengthening PC beams with integrated anchorage. J Reinf Plast Compos2010; 29(9): 1277–1294.
20.
YouYCChoiKSKimJH. An experimental investigation in flexural behavior of RC beams strengthened with prestressed CFRP strips using a durable anchorage system. Composites: Part B2012; 43(8): 3026–3036.
21.
AramMRCzaderskiCMotavalliM. Effects of gradually anchored prestressed CFRP strips bonded on prestressed concrete beams. J Compos Construct2008; 12(1): 25–34.
22.
WightRGGreenMFErkiMA. Prestressed FRP sheets for post strengthening reinforced concrete beams. J Compos Construct2001; 5(4): 214–220.
23.
KimYJWightRGGreenMF. Flexural strengthening of RC beams with prestressed CFRP sheets: development of nonmetallic anchor systems. J Compos Construct2008; 12(1): 35–43.
24.
ACI440.2R-02. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures, Farmington Hills, MI: American Concrete Institute, 2002.
25.
Harries KA, Kasan J, Miller RA, et al. Updated research for collision damage and repair of prestessed concrete beams. NCHRP 20-07 Task 307 Final Report, 2012.
26.
ACI440.2R-08. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures, Farmington Hills, MI: American Concrete Institute, 2008.
27.
Ministry of Housing and Urban-Rural Development. Code of design of concrete structures. Beijing, China, 2002.
28.
WangWWLiG. Experimental study and analysis of RC beams strengthened with CFRP laminates under sustaining load. Int J Solids Struct2006; 43(6): 1372–1387.
29.
HollawayLCTengJG. Strengthening and rehabilitation of civil infrastructures using fibre-reinforced polymer (FRP) composites, Cambridge, England: Woodhead, 2008.
30.
DaiJGHarriesKAYokotaH. A critical steel yielding length model for predicting intermediate crack-induced debonding in FRP-strengthened RC members. Steel Compos Struct2008; 8(6): 457–473.
31.
SaidHWuZS. Evaluating and proposing models of predicting IC debonding failure. J Compos Construct2008; 12(3): 284–299.
32.
Japan Society of Civil Engineers (JSCE). Recommendations for upgrading of concrete structures with use of continuous fibers sheets, Tokyo, Japan, 2001.
