Experimental study of an innovative modular steel building connection

In modular steel building (MSB) built by unit-prefabricated on-site assembled construction method, connections are critical parts that can strongly influence the overall structural stability and robustness of the MSB. Previous MSB connections mainly use intermediate connecting plates, which may pose practical difficulties to certain modular arrangements or installations. Thus, this paper proposed an innovative MSB connection design with an intermediate plug-in device and a beam-to-beam bolt system as the horizontal and vertical connections, respectively. This connection design can ensure convenient installation, eliminating on-site welding. Two static uniaxial loading tests and four quasi-static cyclic loading tests were conducted on the T-shaped MSB connection to explore its load transfer capacity and aseismic behavior. Results showed that gaps would form between the upper and the lower columns because of its two-unit-joint structure. This gap can influence the deformation patterns and bending demand distributions in each unit joint. The weld quality in the unit joints was critical to ensure overall safety. Stiffeners can effectively strengthen the stiffness and load-bearing capacity. The deformation capacity of the connection was significantly influenced by the stiffness of floor beam-column joint and ceiling beam-column joint as well as the relative magnitudes between them.