薄壁方钢管新型梁柱节点抗震性能试验研究

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

为减少薄壁方钢管梁柱连接施焊次数,避免焊接区域脆性恶化,满足"强柱弱梁"的抗震设计要求,提出了一种分散焊接的新型节点。利用往复加载试验对不同轴压比下两类节点的8个足尺试件进行研究。通过对比分析得到新型节点试件的破坏模式、滞回曲线及评价节点抗震性能的主要参数(承载力、延性、刚度退化和能量耗散系数等)。同时,利用非线性有限元模型对两类节点进行了模拟计算,并将计算结果与试验结果进行了对比分析。结果表明:试验与有限元计算结果吻合良好;新型节点延性好,屈服平台长,弹塑性得到充分发挥,累计耗能能力强,能较好地吸收和耗散能量;轴压比对耗能能力及位移发展影响小;新型节点采用分散焊接的方式,提高了节点变形能力,降低了节点板件的脆性,破坏时以C钢腹板屈曲作为破坏准则,节点发生延性破坏,适合在高烈度抗震设防区使用。

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./ks me suimess 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.