Analytical Modeling of Dual Panel Zone in Haunch Repaired Steel MRFs

Abstract

An analytical procedure is presented to model the stiffness and strength of dual panel zones; the dual panel zone in a steel column is formed when the conventional beam-to-column connection in steel moment-resisting frames (MRFs) is enhanced for seismic performance by adding haunches on either or both sides of the column. Based on the results of finite element analysis, a relationship between the unbalanced beam moment and shear deformations in the upper and lower panel zones is established first. Treating the dual panel zone as a two-spring serial system in shear, the equivalent rotational stiffness based on a secant stiffness definition, the yield strength, and the postelastic behavior are derived. The analytical predictions correlate well with the finite element analysis results and available full-scale test results.