Axial mechanical behavior of innovative inter-module connection for modular steel constructions

Modular steel construction (MSC) is a construction mode where volumetric modules are prefabricated in a factory and assembled on-site to form permanent buildings. Inter-module connections are critical to the integrity and robustness of modular steel constructions (MSCs). In this paper, the mechanical behavior of a typical corner inter-module connection under axial tensile and compressive loads was investigated. A tensile test of the inter-module connection was carried out to investigate their axial tensile behavior. The refined numerical model was established, calibrated against the test results and then used to simulate the axial tensile and compressive mechanical behaviors of the inter-module connection. The effects of key design parameters on the axial load-displacement responses of the connection, including the bolt gasket thickness, the bolt diameter and the preload were investigated. The inter-module connection was shown to exhibit excellent load-carrying capacity under axial compression and adequate performance under tension. In terms of tensile resistances, the bolt gasket thickness and the bolt diameter were shown to be the critical parameters, while the section size of the modular columns dominated the compressive load-carrying capacity. Through geometrical parameters correlation analysis, a simplified piecewise polynomial axial load-displacement model with different stiffnesses in tension and compression was employed for predicting the axial load-displacement relationship. The proposed model was shown to be capable of accurately capturing the axial resistance characteristics of the connection while maintaining simplicity, and is therefore recommended for use to represent the axial behavior of the inter-module connection in global frame modelling. •Tensile test of the inter-module connection was carried out.•Refined numerical models for the inter-module connections were established and validated.•Parametric studies were carried out to understand the axial load-carrying mechanism of the inter-module connection.•Damage mechanism and failure mode of the inter-module connection under tension were revealed.•The proposed model can be used to represent axial behavior of the inter-module connection.