基于SMA/ECC的新型自复位框架节#br# 点抗震性能试验研究

为了提高框架节点塑性铰区损伤自修复自复位能力，减小结构的残余变形，实现框架结构震后结构功能的快速恢复，文章采用超弹性SMA筋和超高韧性纤维增强水泥基复合材料(ECC)增强RC框架节点的抗震性能。设计制作了5个1/2缩尺比例框架节点，其中2个为考虑了梁端塑性铰区不同长度的SMA增强ECC节点模型，3个为对比节点模型，即普通混凝土节点、ECC增强混凝土节点和SMA增强混凝土节点。在新型SMA/ECC节点梁端塑性铰区，采用超弹性NiTi-SMA筋代替普通纵筋、ECC代替普通混凝土以增强其复位能力和耗能能力。通过低周往复加载试验，研究了新型节点的破坏过程、耗能能力、位移延性、残余变形和自复位性能。试验结果研究表明：往复荷载作用下，SMA节点均呈现“旗帜形”滞回性能，具有良好的自复位能力；ECC材料够优化框架节点梁端塑性铰的发展，提高结构的延性及耗能能力，延缓结构的屈服；SMA/ECC复合材料系统虽然会降低结构的初始刚度，但能够显著提高节点的延性及自复位能力，延缓刚度退化速度，提高结构抗侧移能力，可以实现结构损伤自修复和功能的快速恢复；覆盖梁端塑性铰区，SMA的长度的改变对自复位性能影响不大。

Experimental study on seismic performance of self-centering #br# beam-column joints reinforced with superelastic SMA and ECC

In order to improve the self-repair ability and self-centering ability of frame joints, reduce the residual deformation of the structure and restore the function of structures after earthquakes, superelastic SMA bars and ECC are used to enhance the seismic performance of frame joints. Five 1/2-scale frame joints were designed and manufactured, including three contrast joints (normal concrete joints, ECC reinforced concrete joints, SMA reinforced concrete joints) and two model joints (ECC joints reinforced by SMA with different lengths). The failure process, energy dissipation capacity, displacement ductility, residual deformation and self-centering performance of the novel frame joints were studied through the low-frequency cyclic loading test, and the self-centering capacity of ECC joints reinforced by SMA with different lengths was also investigated. Test results show that: the ECC material can optimize the development of the plastic hinge at the beam end of the frame, improve the ductility and energy dissipation capacity of the structure, and delay yielding of the structure; SMA-ECC composite system can significantly improve the ductility of the joints and self-centering capability, delay the stiffness degradation, improve the lateral resistance of the structure, but it may reduce the initial stiffness and energy dissipation capacity; the length of the SMA does not significantly affect the self-centering performance of the joint.