Investigation of column axial load effect for bolted-end-plate type steel connections

Abstract

Steel moment resisting frames (MRFs) experience not only lateral movements but also vertical ones during a seismic event. Particularly, the vertical deflections in the members of the structural system cause an increase in the possibility of high column axial compressive loads (CACLs) and correspondingly the bending moment value in the beam-to-column joints. Thus, the beam-to-column joint fails in an unanticipated form. Unfortunately, the available literature about this problem is limited and inconclusive. To help bridge the gap, this study examines the effects of the CACL on the structural behavior of bolted end-plate beam-to-column connections. In this context, this study has three purposes: verifying the experimental tests by the numerical models and evaluating the CACL effect both purely and depending on the variation of fundamental parameter values governing the joint components on the verified numerical models. The numerical analyses of the reference test specimens which are borrowed from the experimental tests in the literature are conducted utilizing a finite element (FE) model including material, geometry, and contact nonlinearities. It is concluded that a possible increase in CACL causes a deterioration in the structural behavior of the beam-to-column connection depending on the moment level transferred from the connection to the column and the shear stiffness of the panel zone.