Dynamic Fracture Behaviour of Cracked H-Shaped Beam-Column Joints with Beam Ends Supported by Columns

The study of the mechanical response and crack propagation behaviour of H-shaped beam-column specimens is of great significance for ensuring the safety and stability of buildings. As a connection structure that has gained ubiquity in modern shopping malls and high-rise buildings, an in-depth exploration of the failure mechanisms of H-shaped beam-column components will facilitate more accurate technical support for building maintenance and service life prediction. The present study employs a combination of drop-weight impact tests and the caustic method to systematically investigate the dynamic fracture characteristics of H-shaped beam-column joints under various prefabricated crack configurations. The results demonstrate that the number and location of cracks in H-shaped beam-column specimens have a significant impact on the propagation path and velocity. Specifically, beam-end cracks are prone to bifurcation, while column-end cracks predominantly initiate from the beam-column intersection. This phenomenon is particularly evident in specimens with prefabricated cracks at both the beam ends and column ends. The propagation of cracks at the beam ends is arrested due to the presence of compressive stress when they reach the beam-column intersection. During this period, the stress intensity of the column-end cracks increases significantly, with a growth rate of 33%.