Restoration of load capacity and stiffness of continuous steel–concrete composite beams having web openings using externally applied FRP strips

The aim of this study is to explore the applicability of externally bonded fiber‐reinforced polymer (FRP) composites to enhance the structural performance of steel–concrete composite beams with web openings in terms of load capacity and stiffness. In order to achieve this aim, the ABAQUS software was used to create a three‐dimensional (3D) non‐linear finite element model (FEM) to simulate the behavior of FRP‐strengthened continuous composite beams with web openings exposed to monotonic loadings. After ascertaining the accuracy of the proposed model's results in successfully predicting failure patterns and load capacities of the experimentally tested specimens available in the literature, the suggested model was used to create a parametric study. The parametric study focused on the impacts of the opening location, opening shapes, and opening area on the failure pattern, load carrying capacity, and stiffness of continuous steel–concrete composite beams. Additionally, strengthening the web openings using different configurations and lengths of FRP strips with and without bolts was investigated. Results showed that the presence of web openings in location 2 exhibited the lowest load capacity of all investigated beams (20.80%–42.50% lower than the control composite beam). Moreover, the continuous composite beams with a circular opening were the best case and gave a higher failure load as compared to the rectangular opening at all locations. Additionally, all the simulated FRP‐strengthened composite beams in the third group demonstrated significant values of load capacities and stiffness among all the analyzed specimens.