Analytical Modeling and Seismic Design of Steel Moment Connections with Welded Straight Haunch

Abstract

This paper describes the analytical modeling and a seismic design procedure for steel moment connections with a welded straight haunch. Recent test results showed that welding a straight haunch beneath the beam could be a viable solution for repair and rehabilitation of pre-Northridge moment connections and also new construction. Although a design procedure for the connection with a triangular welded haunch has been developed recently, it is not applicable for the straight haunch moment connection because the force transfer mechanism is different. Based on the finite-element analysis results, a simplified analytical model that considers the force interaction and deformation compatibility between the beam and haunch is developed. A design procedure as well as details that minimize the stress concentration at the haunch tip is also recommended.