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This paper aims to propose a novel approach to assess the multi-crack behavior of layered fiber-polymer composites. The Compliance and R-curves generated from this novel approach were useful to understand the multiple delamination process, enabling to evaluate separately the strain energy release rate (SERR) related to each crack. A cohesive zone model was developed to simulate the failure process zone of three parallel cracks in web-flange junction (WFJ) specimens extracted from a pultruded bridge deck system subjected to transverse bending. The fracture parameters estimated based on the proposed approach led to a good agreement between the numerical model and the experiments in terms of load vs. displacement curves. Moreover, it was possible to observe that the formation of new cracks may lead to a significant drop on the R-curve, due to the closure of the former cracks. [ABSTRACT FROM AUTHOR]

This paper aims to present an experimental investigation on the behavior of web-flange junctions (WFJs) rotational stiffness of pultruded fiber-reinforced polymer composites (FRP). Channels and I-sections were tested using a simple set-up, which was developed in order to experimentally characterize the junctions in a direct manner. The Digital Image Correlation (DIC) technique was used, allowing overall deflections and relative rotations between web and flange to be monitored. The WFJs' imperfections were analyzed through an optical microscope and correlated with the cracks' formation. Further, damage thresholds are identified using available stress equations for curved composite members and lower bound functions are proposed to simulate the junction stiffness retention. Finally, two Equations are developed in order to analytically predict pultruded junctions' rotational stiffness per unit of width. In general, the theoretical and experimental results agreed fairly well, with a maximum difference of 24% for I-sections and 38% for channels. [ABSTRACT FROM AUTHOR]