ABSTRACT

This study focuses on investigating the effects of the wrapping mode of shape memory alloy (SMA) spirals with a large pre-strain on the lateral cyclic behavior of the bridge columns. The seismic performance of RC columns confined with different NiTiNb SMA spirals spacing and wrapping heights is compared through a series of quasi-static tests. The confined columns are tested under compression and cyclic lateral loadings. The lateral cyclic behavior of confined columns is compared with that of the as-built column. The test results demonstrate that NiTiNb SMA with a large pre-strain significantly improves the ductility and energy dissipation capacity, and has a slight effect on the peak lateral strength of the bridge piers. The SMA spirals reduce the crashing concrete zone and delay the buckling of steel bars in spite of the crack range in the SMA specimens increasing compared with the control column. The reinforcement effect increases as the SMA spirals spacing decreasing, particularly in terms of ductility and energy dissipation. The damage pattern has a slight distinction in the specimens strengthened by different wrapping mode.

摘要

本研究的重点是研究具有大预应变的形状记忆合金 (SMA) 螺旋的缠绕模式对桥柱横向循环行为的影响。通过一系列准静态试验比较了不同NiTiNb SMA螺旋间距和缠绕高度约束的RC柱的抗震性能。约束柱在压缩和循环横向载荷下进行测试。将受限柱的横向循环行为与竣工柱的横向循环行为进行了比较。试验结果表明，预应变大的NiTiNb SMA显着提高了延性和耗能能力，对桥墩的峰值横向强度影响不大。尽管与对照柱相比，SMA 试件的裂缝范围有所增加，但 SMA 螺旋减少了混凝土碰撞区并延迟了钢筋的屈曲。增强效果随着 SMA 螺旋间距的减小而增加，特别是在延展性和能量耗散方面。不同包裹方式加固后的试件损伤模式略有不同。