Progressive collapse performance of beam-column joint with WUF-B-RW connection after high temperature

Abstract

This paper studied the progressive collapse resistance of 10 beam-column joints with post-high-temperature through static tests. The size of the ten specimens is the same, and the connection form is bolt-welded connection. Among them, one specimen was at room temperature, and the other nine specimens were treated at 400 °C, 600 °C, and 800 °C and held at the temperature for 30, 60, and 90 min, respectively. The load-displacement curve, deflection curves, and strain development of the critical section of the specimen were studied, and the axial force, bending moment, bending resistance, and catenary mechanism of the specimen were calculated according to the test results. Before and after high temperatures, the failure of specimens is beam-end damage. Temperature only affects the initial position of failure of beam-column joints. The duration time has no noticeable effect on the properties of the steel. Based on the test results, it is found that at the same duration time and different high temperatures, the higher the temperature, the smaller the maximum vertical load and joint rotation angle at failure, and their axial force and bending moment are also weaker. However, there is no difference between the plastic limit rotation angles of the specimens. At the same temperature and different duration, the load-displacement curves of the specimens are very similar. It can be seen that at the same temperature, the duration time has little effect on the mechanical properties of the specimen. At the same time, although the mechanical properties of the specimens were weakened after high temperatures, they still maintained an excellent ability to resist progressive collapse. Even the beam angle of the member with the smallest failure angle was 0.15 rad, more significant than 0.06 rad. The finite element model established by ABAQUS is mutually verified with the test results to prove the accuracy and effectiveness of the finite element model. Based on this model, the expanded parametric analysis is carried out to analyze the influence of hole spacing and hole diameter on the progressive collapse resistance of the specimen after high temperature.