EXPERIMENTAL RESEARCH ON SEISMIC BEHAVIOR OF A NEW TYPE OF THIN-WALLED SQUARE STEEL TUBE BEAM-COLUMN CONNECTION

In order to reduce the number of repeated welding, avoid brittle fracture and meet the seismic design principle of "strong column and weak beam", a new type of beam-column connection is proposed by adopting decentralized welding. Through the cyclic loading test, two types of 8 beam-column connections under different axial compression ratios are studied. According to the comparison of results, Failure modes and hysteretic curves of the new-type connection are obtained, and main parameters for estimating the earthquake resistant behavior of a new-type connection are also studied, such as load-carrying capacity, ductility ratio, stiffness degenerated and energy dissipation coefficient. Meanwhile, the nonlinear finite element models are also used to analyze the seismic behavior of the connection by ANSYS, and the results is also compared with experimental results. It can be found from the research that: analytical results agree well with experimental results, and the theoretical analysis is verified correctly; the new-type connection can experience much cycling time, has a long yield platform after yield and stronger cumulative energy-dissipating capacity and better ductility. This can make connection to consume much energy in earthquake and meet the need of seismic design very well. As the stiffness is reduced by the composite beam, load-carrying capacity of the new-type connection is lower than that of general connection, and decreased with axial compression ratios; the axial compression ratio has great influence on hysteretic behavior and failure characteristics of a general connection, but little on the new-type connection.