Experimental study on monotonic loading of joint of multi-limb assembled cold-formed thin-walled steel concrete composite column and H-shaped steel beam

Modular wall light steel concrete composite structure is a new type of prefabricated insulation and load-bearing integrated structure. To thoroughly investigate the static performance of its beam-column joint, namely multi- limb assembled cold-formed thin-walled steel concrete composite column and H-shaped steel beam joint (MCTSCC-HSB joint), monotonic loading tests were conducted on eight MCTSCC-HSB joint specimens. The experimental results show that the joints exhibit obvious semi-rigid characteristics. Firstly, plastic deformation occurred at the upper and lower flange of the beam end, and then the bending deformation of the upper flange angle steel increased continuously. Finally, the cracking of the stiffener weld of the upper flange angle steel leaded to the failure of the joint, the columns of a few specimens at the joints tension area appeared bulge and concrete cracking. It can be seen by parametric analysis that increasing the thickness of C-shaped steels in MCTSCC can reduce the bulge and concrete cracking mention above, joint stiffness can be improved by increasing the number of bolt rows on the angle steel connectors of web or flange of beam, while axial compression ratio and concrete strength grade have little influence on the static properties of the joints. Additionally, finite element models (FEM) were developed to analyze the bending capacity and rotational stiffness of the joints, both the failure characteristics and load-displacement curves of FEMs align with those of the test, which verifies the rationality and reliability of FEMs established in this study.