螺栓端板连接节点加固后承载性能有限元分析

已有试验表明，螺栓端板连接梁柱节点具有良好的受力性能，但节点刚度较小，循环荷载作用下破坏模式以螺栓拉断为主。当建成的结构由于各种因素螺栓端板节点承载性能不能满足要求时，需要进行加固以提高节点刚度和承载力。改：善其抗震性能，本文提出了在柱腹板加斜向加劲肋，并对端板进行焊接的加固方案。有限元分析表明加固后节点的刚度、延性和承载力都得到提高。静力加载时，荷载一位移曲线在达到峰值后出现平缓的下降段；循环加载时，节点破坏模式是梁翼缘发生局部屈曲形成塑性较，滞回曲线饱满。由于使用了焊缝，节点有可能发生脆性破坏，加固中应尽量使用较小尺寸的焊缝，施工中也应保证焊缝的质量，减小残余应力。

Finite Element Analysis on Retrofitting End-plate Connections

Experimental results of end-plate connections showed that this type of connections have efficient load capacity, but with low stiffness. Under cyclic loads, the failure modes were controlled by the fracture of bolts, leading to a brittle behavior. To achieve higher joint stiffness and uhimate capacity and improve seismic resistant performance, stiffeners were applied to the panel zone in addition to the fillet weld between column flange and end-plate. Finite element analysis indicates that after reinforcement, a more stiffer connection was obtained under monotonic loading, and better hysteresis loops are observed under cyclic loads with large plastic rotation formed by the local buckling of the beam flange near the column face. This retrofitting scheme employs fillet weld, which has lower toughness, may also suffer brittle failure. Smaller size of weld is recommended and the quality should be guaranteed in order to reduce the residual stress of the fillet weld.