极端温度对钢管混凝土格构式高墩抗震性能影响研究

Study on influence of extreme temperature on seismic performance of concrete-filled steel tube lattice high pier

为研究极端环境温度对钢管混凝土(CFST)格构式高墩抗震性能的影响,以某CFST格构式高墩斜拉桥为背景,开展温度对钢管混凝土材料特性的影响试验。通过建立桥梁空间有限元模型,探究极端环境温度对全桥自振特性和地震响应的影响,并运用地震易损性分析,得到不同温度工况下CFST格构式高墩的损伤概率。研究结果表明:当环境温度为-40~40℃时,混凝土弹性模量和峰值应力与温度呈负相关,钢材的力学参数受温度影响不明显;考虑材料温变特性后,CFST格构式高墩各阶自振频率随温度下降而升高;极端环境温度引起CFST格构式高墩材料力学性能的改变,高温工况下墩顶位移比常温工况显著增加;低温工况下,不同破坏程度的CFST格构式高墩损伤概率比常温工况均显著增大。研究结果可为高寒地区CFST格构式高墩抗震设计提供参考。

In order to study the influence of extreme ambient temperature on the seismic performance of concrete filled steel tube(CFST)lattice high pier,the influence of temperature on the material properties of CFST was tested taking a cable-stayed bridge with CFST lattice high pier as the background.By establishing the spatial finite element model of the bridge,the influence of extreme ambient temperature on the natural vibration characteristics and seismic response of the bridge was explored,and the seismic fragility analysis was used to obtain the damage probability of CFST lattice high pier under different temperature conditions.The results show that when the ambient temperature is-40~40℃,the elastic modulus and peak stress of concrete are negatively correlated with temperature,while the mechanical parameters of steel are not obviously affected by temperature.Considering the temperature variation characteristics of the material,the natural vibration frequency at each order of the structure increase with the decrease of temperature.The extreme ambient temperature causes the change in the mechanical properties of CFST lattice high pier materials,and the displacement of pier top under high temperature condition is significantly higher than that under normal temperature condition.Under low temperature conditions,the damage probability of CFST lattice high piers with different damage degrees is significantly higher than that under normal temperature conditions.The research results can provide reference for the seismic design of CFST lattice high piers in alpine regions.