Mechanical behavior of web–flange junctions of thin-walled pultruded I-profiles: An experimental and numerical evaluation

This paper presents experimental and numerical results of the first phase of a multi-phase comprehensive joint research program between University of Salerno, Italy, and the University of California, Irvine, USA, on investigating one of the major structural issues that defines the strength limit-state of pultruded fiber-reinforced polymer (PFRP) profiles.Specifically, the strength and stiffness of the web–flange junction (WFJ) of the majority of commercially-produced pultruded composite profiles. A summary of experimental results for 28 full-scale pull-out tests are presented and typical modes failure are identified. Moreover, the influence of the pull-out load distance (d) from the edge of the specimens on the failure strength of the web–flange junction has been investigated and a new definition for an “influence zone” is proposed that is found to be dependent on the loaded length, with a maximum value equal to approximately the PFRP member’s depth. This proposed zone was observed in all laboratory tests and its existence was confirmed by the results of FEM numerical analysis. 3-D finite-element models were also developed to predict the behavior of these specimens. The results from the numerical models were compared to those obtained from the experimental program and found to be satisfactory.