Experimental and analytical investigations on compression behaviors of rotary-connected sway column-supported steel modular interior frames

Abstract

This study examines the compressive behaviors of sway column-supported steel modular interior frames (SCSMIFs) using rotary-type vertical and horizontal inter-modular connections (IMCs). The compression behavior of SCSMIFs was investigated through experimental, numerical parametric, and analytical techniques. Findings indicate that the relative rigidity of beam-to-column connections primarily influences lateral translation. Adjacent upper columns displayed symmetrically inward or outward elastic and plastic S-shaped local buckling without IMC failures. A finite element model (FEM) was developed and validated, achieving a 1% average prediction error for compressive resistance. The examination of 87 SCSMIFs with a validated FEM revealed the effects of different parameters on compressive resistance, initial stiffness, and pre-and post-ultimate ductility. Based on member stiffnesses and rotary-type IMCs in semi-rigid and pinned conditions, theoretical models predicted sub-assembled CMSIF buckling loads. The average theory-to-FEM results for pinned and semi-rigid IMCs were 0.70 and 0.95, indicating that incorporating the stiffness of rotary-type IMCs resulted in more accurate and less scattered buckling load predictions. Considering their unique characteristics, the study's findings contribute to ensuring the structural integrity and design of SCSMIFs with IMCs under compressive loads.