Performance of Bolted Angle Connections under Dynamic Load

Following progressive collapse and transition into the large-deformation stage, pure tensile stress emerges as the dominant force mechanism at the joint. However, due to the dynamic nature of the collapse, static tensile tests on the connections fail to accurately represent their dynamic mechanical behavior during the collapse process. Consequently, dynamic tensile testing of the connections is necessary. In this study, dynamic tensile tests were performed on 20 sets of bolted angle connections, focusing on the bearing capacity, failure modes, and mechanical performance under dynamic load. The effects of key parameters such as bolt strength, gauge length, and angle thickness were systematically discussed. Based on the experimental results, finite-element models were established. After verification of the experimental results, parameters such as bolt diameter and number of rows were analyzed with respect to mechanical performance indicators. The experimental and finite-element analysis results demonstrate that the impact force time-history curve of the bolted angle specimens under dynamic tensile loading can be segmented into four distinct stages, while the load–displacement curve can be delineated into seven different phases, all of which were meticulously classified. Experimental observations revealed three main failure modes: fracture of the angle along the bolt hole, penetration of the angle by the bolt, and complete bolt fracture. The findings indicate that bolt strength significantly impacts postyield stiffness; angle thickness dramatically affects bearing capacity and failure modes. Excessive thickness of the angle diminishes the relative effect of bolt strength, causing the bolt to fail due to reaching its ultimate strength; increasing the bolt diameter and number of rows directly enhances initial stiffness and bearing capacity, while bolt gauge length plays a crucial role in balancing the stiffness and ductility of the joint. This research provides a reliable basis for the design of connections under dynamic load.