Improved Truss Model for Design of Welded Steel Moment-Resisting Frame Connections

Abstract

This paper presents results of finite element analysis of 18 strong-axis steel welded beam–column subassemblages with connection reinforcement. For the type of connection configuration considered, Federal Emergency Management Agency (FEMA) recommends that the connection forces be obtained by locating the plastic hinge at one-third depth of beam away from the end of connection reinforcement region. Also a recent study pointed the location of plastic hinge to be at a distance of depth of beam from the column face. However, the present study shows that the plastic hinge is located at one-half depth of beam away from the end of connection reinforcement region. It is observed that the connection design forces obtained from the present study are higher as compared to those obtained using the FEMA recommendations. The paper also presents a noniterative procedure for the design of beam-to-column connections using a truss for obtaining connection forces, which uses this location of the plastic hinge.