可更换构件铁路高墩抗震性能研究

Seismic performance of railway high piers with replaceable members

摘要:

针对一种具有可更换构件的新型铁路高墩结构,基于增量动力分析(IDA)曲线,采用易损性分析方法对9度设计、罕遇与极罕遇害地震时的墩柱进行抗震性能评价。建立全桥有限元分析模型,以墩柱最不利截面材料的应变为损伤指标,以地面峰值加速度为地震动强度指标,以357条地震波作为地震动输入,IDA分析得到墩柱关键截面的IDA曲线簇及50%、84%和16%的分位曲线,结合定义的极限状态,探讨墩柱可能产生的塑性铰数量及位置,并通过绘制易损性曲线,对墩柱进行基于概率性的抗震性能评估。研究结果表明:可更换构件在桥墩中首先屈服,从PGA=0.5g时开始屈服、到PGA=1.1g时全部屈服,可更换构件实现分级耗能;墩柱在9度罕遇地震作用下处于基本完好的概率约为99.5%;可更换构件新型高墩结构在9度巨震下超越基本完好状态的概率为36.6%,超越可修复性损伤状态的概率不足1%,其大概率处于可修复性损伤状态。可更换构件高墩抗震性能优越,在近断层地区具有较好的应用前景。

Abstract:

Based on the incremental dynamic analysis (IDA) curve, this paper evaluated the seismic performance of high pier columns of a novel railway bridge with replaceable members under 9-degree design, rare, and huge earthquakes. A finite element analysis model of the whole bridge was established. Strain of the most unfavorable section of the pier column was chosen as the damage index, and the ground peak acceleration was chosen as the seismic intensity measure. Under the input of 357 seismic waves, the IDA curve cluster and 50%, 84%, and 16% curves of the key sections of pier column were obtained through the IDA analysis. Combined with the defined limit state, the number and location of possible plastic hinges on the pier column were discussed, and the seismic performance of pier column was evaluated by drawing vulnerability curve. The results show that the replaceable members yield first in the pier, from PGA=0.5g to PGA=1.1g, and the replaceable members realize graded energy consumption. The probability of pier column in nearly intact state under the action of 9-degree rare earthquake is about 99.5%. For the novel high pier structure with replaceable members proposed in this paper, the probability of exceeding the nearly intact state under 9-degree earthquake is 36.6%, and the probability of exceeding the repairable damage state is less than 1%. The high pier structure with replaceable members has excellent seismic performance and has a good application prospect in near fault areas.