Numerical study of PPVC modular steel constructions (MSCs) with selected connection strategies under varied earthquake scenarios

Abstract

Modular steel construction (MSC) represents an innovative approach in civil engineering. Yet, the complexities of its structural response to seismic forces are not fully understood, nor is the practicality concerning its connection systems. Traditional analytical models, often linear and elastic, fail to capture the MSC connection's nuanced, non-linear behaviour under seismic stress. This research embarks on a detailed numerical and parametric analysis of three MSC systems, introducing a novel stiffness coupling spring matrix approach to reflect the connection's behaviour more accurately in seismic conditions. The study analysis identifies MSC1 as demonstrating resilience, with intra and internal inter-module connections experiencing displacement up to 0.719 m and 0.685 m, respectively, under a 7.7Mw Chi-Chi earthquake. Conversely, MSC2, under a 6.7Mw Denali earthquake, highlights an urgent need for design optimisation, with connections displacement up to 0.714 m. MSC3 exhibits superior structural integrity and seismic resilience during a 5.3Mw Kocaeli earthquake, achieving a stiffness peak of 5499.1 N/m and registering minimal displacement of 0.184 m and 0.177 m in intra and internal inter-module connections. Further, a sensitivity analysis incorporating ±10% stiffness variations is crucial in seismic resilience. MSC1 and MSC2 display pronounced sensitivity, particularly MSC1's intra-connection with displacement fluctuations up to 0.789 m and a decrease to −8.273 m. This analysis underscores the imperative for enhanced stiffness in MSC3's external inter-module connections to withstand less severe seismic impact while necessitating increased stiffness for MSC1 and MSC's corner inter-module connections. Maintaining consistent stiffness in module-to-foundation connections is essential for models, notably on MSC1 and MSC2, highlighting the intricate challenge of engineering MSC systems for peak seismic performance.