Proceeding of
4th International Conference on Advanced Composite Materials in Bridges
and Structures, (ACMBS IV)
Calgary, Alberta, Canada, July, 2004. CDROM
RECENT research on intermediate
crack Debonding in FRP-strengthened RC beams
J.G. Teng
Department of Civil and Structural Engineering, The Hong Kong Polytechnic
University
Hung Hom, Hong Kong, PR China
cejgteng@polyu.edu.hk
X.Z. Lu, L.P. Ye and J.J. Jiang
Department of Civil Engineering, Tsinghua University
Beijing, PR China, 100084
luxinzheng@sina.com.cn ylp@tsinghua.edu.cn jiang-jj@tsinghua.edu.cn
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PDF version ABSTRACT: An important failure mode for an RC beam strengthened with an externally bonded FRP plate is debonding of the FRP plate from the soffit of the beam due to major flexural cracks. In this failure mode which is commonly referred to as intermediate crack (IC) debonding, debonding initiates at a critical section in the high moment region and then propagates to one of the plate ends. Despite many experimental and theoretical studies, accurate predictive models for IC debonding failures have not been developed. This paper presents a new smeared crack approach for the finite element simulation of the IC debonding process, in which a new model for the FRP-to-concrete interface capable of capturing the effect of local slip concentration near a flexural crack is proposed. The finite element model is shown to be accurate through comparisons with the results of 45 beam tests. The paper also presents an accurate and simple design model based on interfacial shear stress distributions from finite element analysis. The new design model is shown to be accurate through comparisons with the test results of 73 beams, including the 45 beams used in verifying the FE model.