Experimental and numerical investigation of concrete cylinders strengthened with <scp>BFRP</scp> grids

Abstract With the aging infrastructure and growing demands for behavior enhancement, strengthening and repair techniques for concrete structures have become a research focus in the field of civil engineering. To clarify the strengthening mechanism of basalt fiber‐reinforced polymer (BFRP) grids on the axial compressive behavior of concrete columns, this study adopts a combined experimental and finite element simulation approach to conduct a systematic investigation into BFRP grid‐confined concrete cylinders. The experimental study systematically examines the effects of grids layer number, specimen size, and different strengthening configurations on the axial compression performance of the cylinders. Furthermore, using ABAQUS software, the influences of concrete strength, BFRP wrapping configurations, and specimen size on the mechanical behavior are analyzed. The results indicate that BFRP grids significantly improve the ductility of concrete, with the strengthened specimens exhibiting typical ductile failure characteristics. As the number of grids layers increases from one to three layers, the ultimate bearing capacity of the specimens improves by 8.6%, 35.2%, and 35.8%, respectively. The study also reveals a threshold effect of grids layers: beyond two layers, the risk of interfacial debonding increases, resulting in limited further gain in ultimate load. The experimentally validated finite element model predicts the ultimate bearing capacity with an error within 15% and accurately simulates the failure modes of the specimens. Based on the experimental data, key coefficients in existing FRP confinement models are recalibrated. The modified model demonstrates high accuracy in predicting the ultimate bearing capacity of BFRP grid‐confined concrete, with errors controlled around 10%.