Interface bond between FRP systems and substrate: Analytical modeling

Ascione Francesco; Napoli Annalisa; Realfonzo Roberto

摘要

In the field of external strengthening and repairing of existing reinforced concrete structures, steel reinforced polymers (SRP) systems have emerged as a competitive alternative to the use of the more common carbon and glass fiber reinforced polymer (FRP) composites. Experimental investigations have frequently shown the potentials of these innovative composite systems in improving the performance of deficient structural members. At the same time, additional studies are needed to expand the existing knowledge and either to provide design recommendations or to develop specific guidelines. The paper fills some of the foregoing knowledge gaps by presenting an analytical investigation on the bond behaviour between SRP and concrete in which closed form solutions are derived to predict the entire debonding propagation process. In particular, accurate and simplified local shear stress-slip (tau-s) laws are employed in the proposed modelling from which different expressions for the interfacial shear stress distribution, the axial stress profile and the concrete-SRP relative displacement (slip) are developed and commented in the paper; analytical estimates of the SRP effective bonded length are provided as well as relationships for calculating the maximum axial stress (or peak force) at SRP laminate debonding.The analytical procedure was, firstly, applied to simulate some single-lap shear tests performed in a previous experimental program with the purpose to investigate the influence on the debonding propagation process of the following main parameters: a) concrete strength, b) concrete surface finish and c) steel tape density. Then, the comparisons between the numerical simulations and the experimental results available for some bond tests have allowed for verifying the accuracy of the proposed modelling.

机译：在现有钢筋混凝土结构的外部强化和修复领域，钢筋聚合物（SRP）系统已成为使用更常见的碳和玻璃纤维增强聚合物（FRP）复合材料的竞争替代品。实验研究经常显示了这些创新性复合体系的潜力在提高了结构构件的缺陷性能方面。与此同时，需要额外的研究来扩大现有知识，并提供设计建议或制定具体指导方针。本文通过提出对SRP和混凝土之间的粘合行为的分析研究来填补一些前述知识差距，其中得出了封闭的形式溶液来预测整个剥离传播过程。特别地，在建议的建模中采用精确和简化的局部剪切应力滑动（TAU-S）定律，从而开发了用于界面剪切应力分布，轴向应力分布和混凝土-SRP相对位移（滑动）的不同表达式的建模并评论论文;提供SRP有效粘合长度的分析估计以及用于计算SRP层压板剥离的最大轴向应力（或峰值）的关系。第一步应用于模拟在前一个单圈剪切测试的分析程序。实验计划目的，研究了对以下主要参数的剥离传播过程的影响：a）混凝土强度，b）混凝土表面光洁度和c）钢带密度。然后，可以允许验证建议建模的准确性的数值模拟与某些键测试的实验结果之间的比较。

Interface bond between FRP systems and substrate: Analytical modeling

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