Bond-slip models for the FRP-concrete interface are proposed based on meso-scale FE results.

These models are better than any other existing design or analysis models.

Supervisors: Prof. J. G. Teng of the Hong Kong Polytechnic University. Prof. L. P. Ye and J. J. Jiang of Tsinghua University.

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Bond-slip models for FRP sheets/plates externally bonded to concrete.

Engineering Structures. 2005. 27(6). 920-937

ABSTRACT: An accurate local bond-slip model is of fundamental importance in the modelling of FRP-strengthened RC structures. In this paper, a review of existing bond strength models and bond-slip models is first presented. These models are then assessed using the results of 253 pull tests on simple FRP-to-concrete bonded joints, leading to the conclusion that a more accurate model is required. In the second half of the paper, a set of three new bond-slip models of different levels of sophistication are proposed. A unique feature of the present work is that the new bond-slip models are not based on axial strain measurements on the FRP plate; instead, they are based on the predictions of a meso-scale finite element model, with appropriate adjustment to match their predictions with the experimental results for a few key parameters. Through comparisons with the large test database, all three bond-slip models are shown to provide accurate predictions of both the bond strength (i.e. ultimate load) and the strain distribution in the FRP plate.

KEYWORDS: FRP, concrete, bond, bond-slip models, bond strength, pull tests, finite element simulation, composites

Bond-slip models for FRP sheet/plate-to-concrete interfaces ,

Proceedings of 2nd international Conference of advanced polymer composites for structural applications in construction (ACIC2004). Hollaway L C, Chryssanthopoulos M K, Moy S S J, eds. Cambridge, England: Woodhead Publishing Limited, 2004: 152-161.

Abstract: A meso-scale finite element model is first presented for simulating the debonding behavior of FRP-to-concrete bonded joints in simple shear tests. In this model, both the FRP plate/sheet and the concrete are modeled using elements of mesoscopic sizes so that the shapes and paths of cracks during the entire debonding process can be appropriately captured. Results obtained from this model are next presented to provide insight into the debonding failure process. Finally, based on a finite element parametric study and existing test results, three bond-slip models of different levels of sophistication are presented. These proposed models are far more accurate than all existing bond-slip models.

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