Effects of modeling of the welded vertical inter-module connection on the nonlinear dynamic response of a low-rise modular steel building

Abstract

Modular steel buildings (MSB) are now recognized as a rapid solution to address urgent housing needs across the globe. Volumetric MSBs consist of prefinished 3-D modules produced off-site and assembled on-site to form a permanent building. Depending on the structural mechanism, continuously- or corner-supported modules can be used to transfer the loads all the way to the foundation. When the latter is selected, diaphragm action and inter-module connections play a crucial role and may cause considerable differences in the nonlinear dynamic performance of MSBs. Despite the availability of various connection options and proposed alternatives as research on MSBs continues, on-site welding remains one of the methods used for vertical connectivity between the modules. This paper offers a comparative analysis aimed at identifying the effects of various welded connection models on the overall nonlinear dynamic response. For this purpose, two existing models of welded vertical inter- module connection (VC1 and VC2) from the literature, both were calibrated using experimental data, were selected and studied on a 4-story MSB. In order to obtain the parameters of VC2, detailed finite element analyses were carried out using Ansys software. Consequently, two different 3-D global models were developed using OpenSees to investigate the system-level nonlinear dynamic response of the selected building under bidirectional ground shaking. In addition, the base shear values, inter-story drift ratios, and hinge formation sequences of structural elements were investigated and compared between the two global models with different inter-module connection models to shed light on the dynamic performance of the building subjected to bidirectional ground shaking. The results show that the simpler model (VC1) does not cause dramatic differences in the nonlinear dynamic response of the low-rise MSB, even though it slightly overestimates the lateral response of the inter- module connection.

Reference

• Batukan, M.B., & Mercan, O. (2023). Effects of Modeling of the Welded Vertical Inter-Module Connection on the Nonlinear Dynamic Response of a Low-Rise Modular Steel Building. Canadian Conference - Pacific Conference on Earthquake Engineering 2023. https://ccee-pcee.ca