Collapse mechanism of three-dimensional modular steel buildings: Effect of steel wall and difference with traditional steel frame

Abstract

This paper presents a numerical study on the collapse performance of 3-D MSB (modular steel building) in four module-removal scenarios: removals of a single corner module, single edge module, single interior module, and two edge modules. The final global deformation, resistance-displacement relationship, inter-module connection force, and contribution of the steel wall of the MSB structure are reported. The difference of the collapse mechanism between the MSB structure and traditional steel frame structure is also elaborated. It is found that using a 2-D model will significantly overestimate the deformation of the MSB structure in corner module loss due to the neglect of the floor slab, ceiling slab, and steel wall in the orthogonal direction. Under the interior and edge module loss circumstances, significant compression buckling can be observed in steel walls of the structure. In the condition of corner module loss, however, diagonal tension zones are found in the steel walls. The contribution of the steel wall to the resistance of the MSB structure in different module-removal scenarios is about 35%–66%. The existence of the steel wall delays the development of the tensile force and even results in compression force in the connection. In the two-edge module-removal scenario, when the steel wall is not considered, the MSB structure performs as a traditional steel frame, in which all connections between the adjacent modules are in tension. However, when the wall thickness increases, the tension in connections at the upper storey of the MSB structure decreases and may even changes to be in compression.