ANALYSIS OF STEEL FRAME WITH SEMI-RIGID CONNECTIONS AND CONSTRAINTS USING A CONDENSED FINITE ELEMENT FORMULATION

: This paper proposes a novel method for analyzing steel frames with semi-rigid connections and displacement constraints, using a condensed finite element formulation. The paper outlines a systematic approach for constructing the condensed stiffness matrix and the condensed force vector. The proposed analysis can predict accurately the nonlinear effects of connections on the behavior and strength of semi-rigid steel frames. Kishi-Chen power model is applied to describe the nonlinear behavior of semi-rigid connections. The proposed method's effectiveness is demonstrated through analytical and numerical analysis of a semi-rigid steel frame structure, highlighting the procedure's simplicity and robustness. To verify the validity and applicability of the proposed method, several examples of realistic structures and benchmark cases are provided. The strengths predicted by the proposed method demonstrate good agreement with the available experimental results.