Damage Control of Composite Steel Beams Using Flexible Gel-Covered Studs

This paper proposes flexible-gel-covered (FGC) studs to reduce the seismic damage of a concrete floor slab in a steel frame. Flexible gel strips intentionally release the shear constraint between the slabs and the steel beams. To evaluate the effectiveness of the proposed FGC studs, a proof-of-concept test was conducted. Three beam-column connection specimens with different shear-constraint configurations were designed and quasistatically tested according to a seismic loading protocol. The load-deformation relationship, crack development, and other results were obtained and indicated that the slab cracking and beam strain were reduced, whereas the initial stiffness and load-carrying capacity also slightly decreased. The results are promising but not satisfactory, and the current design still requires extensive floor slab repair after a large earthquake. Thus, the appropriate shape and configuration of the FGC stud must be further investigated. Based on the test results, a sophisticated finite-element numerical model was developed using widely used commercial finite-element computer software, and could reproduce the hysteresis behavior, including the beam-end fracture. Finally, parametric analyses were conducted to obtain the desirable shear-constraint behavior. (C) 2019 American Society of Civil Engineers.