Study of replaceable and static properties of assembled steel coupling beams with different connection modes

Abstract

To improve the seismic energy dissipation capacity and quick recovery capacity of buildings, the use of replaceable components is a key research area in the field of earthquake engineering, of which the design and performance of replaceable coupling beams are one of the focuses of the research. To study the influence of connection modes on the replaceability and mechanical properties of a replaceable steel coupling beam after an earthquake, three types of connection modes for an I-section energy-dissipating beam have been designed in this study. They are the lug plate-bolt group connection (CB1), end plate-bolt group connection (CB2), and end plate-bolt-shear key connection (CB3). Full-scale model replacement tests of replaceable steel coupling beams with the three types of connections were carried out. Furthermore, a real-time 3-dimensional attitude model was developed to assess the replaceability of a coupling beam after an earthquake. In addition, full-scale model static load tests and finite element simulations of the coupling beams were carried out. The mechanical characteristics, such as the bearing capacity, stiffness, and failure mode under monotonic static loading, have been analyzed. The results of the replacement test show the following. The maximum replaceable residual shear angles of the energy-dissipating beams with CB1, CB2, and CB3 are 0.008 rad, 0.007 rad, and 0.01 rad, respectively. Of the three types of connections, the operation of replacing CB3 is the easiest. The results of the static load test and the finite element simulation show the following. The connection modes of the energy-dissipating beams and the nonenergy-dissipating beams have a great influence on the stiffness of the coupling beams and some influence on the deformation capacity of the coupling beams. However, the types of connections have no obvious influence on the bearing capacity of the coupling beams. According to the comprehensive comparison, the plastic deformation of CB3 is more concentrated on the web of the energy-dissipating beam, and the safety reserve of the connecting joint is higher, which shows that the design of CB3 is better than those of CB1 and CB2.