Mechanical performance of stud connection in steel-concrete composite beam under reversed stress

During earthquakes, concrete slabs in composite beams are subjected to cyclic compressive and tensile stresses. Previous experimental tests indicated that the strength in the cyclically loaded stud connections degraded faster than in ordinary monotonic push-out tests. To assess the mechanical performance of the local composite connection, this research first calibrates a finite element analysis (FEA) model of subassembly specimens. Using the experimentally validated FEA model, a parametric study was conducted with various stud and reinforcement sizes and configurations, material properties, slab widths, and loading protocols. A comprehensive analysis quantified the effects of influential factors on mechanical behaviour and performance. The results were compared with the previously constructed equations to assess the ultimate stud connection strength. As a novel approach from a previous study, the stud connection stiffness is newly evaluated, using classical theory and empirical formulae and a new mathematical model was proposed.