Mohamadreza Shafieifar - Florida International University, Department of Civil and Environmental Engineering, Miami, ۳۳۱۷۴, USA.
Vahid Khonsari - Sharif University of technology, Department of Civil Engineering, Tehran, Iran

Base plates are one of the most important types of connections in structures. Due to complicated steel-concrete interaction,simple assumptions of the stress distributions are usually employed for designing the connection. Simple assumptions ofcompressive stress distribution in concrete may accelerate the design procedure, but they may lead to overdesign results.In this study, six different types of base plates with different configuration were studied numerically using a commercialFinite Element (FE) software and the numerical model was calibrated with an experimental test. The models were subjectedto a constant axial load and then a monotonic moment loading was applied. To investigate the effects of the axial load,several axial load level were considered for each configuration. As a result, moment-rotation curves of these base plates,including their rotational stiffness, in the absence and presence of the axial loads, were compared. Moreover, the stressdistribution in the concrete was studied in the FE models. For all cases, the stress distribution in the concrete was semitriangularwith the maximum stress between the column flange and the edge of the plate. Based on numerical results, someconcepts of simplified assumptions were proposed to find the stress distribution of the base plates. These assumptions aremore realistic than current assumptions in structural specifications.

Base Plate; Column Base; Concrete Damage Plasticity; CDP; Stress Distribution; Finite Element Modeling