BEHAVIOR OF WELDED BOLT SHEAR CONNECTORS SUBJECTED TO REVERSED CYCLIC LOADING

Conventional bolts fillet-welded to steel and embedded in concrete have been a common method of force transfer between steel and concrete materials in composite construction in some Latin American countries. Welded bolt shear connectors have been used in both low-rise and mid-rise constructions replacing headed steel stud shear connectors. Whereas the installation of headed studs requires the use of a special high voltage equipment, welded bolts can be welded with fillet welds using shielded metal arc welding process more economically. Welded bolt shear connectors are also used in lateral load resisting composite systems. Natural cyclic loads from earthquakes cause connectors to be subjected to alternating shear forces. For this reason, the cyclic behavior of shear connectors is particularly important in these systems. In this study, a series of experimental tests on composite push-out specimens with welded bolt shear connectors were performed to investigate the behavior of shear connectors subjected to fully reversed cyclic loading. Of specific interest was the behavior under low-cycle fatigue. Results show up to 57 % reduction in connector shear capacity under reversed cyclic loading compared to static capacity.