摘要
为厘清小剪跨比圆端铁路桥墩横桥向的地震损伤机理,以国内某铁路沿线桥梁为参考开展3组缩尺比1∶8的拟静力试验,对滞回曲线的延性、残余位移、滞回耗能和刚度退化4个方面进行分析,以试验结果为参考使用OpenSees建立纤维截面有限元模型并进行耐震时程动力计算,以桥墩的位移延性比为损伤指标,基于试验中观察得到的4个关键节点定义无、轻微、中度、严重和完全损伤5种损伤状态之间的位移延性比临界值,通过易损性分析桥墩的损伤发展历程。研究结果表明:1)配筋率从0.3%提升至0.7%,桥墩的承载能力提高至1.37倍,极限位移提高至1.22倍,最终残余位移提高至1.55倍,耗散能量增加至1.80倍,初始刚度提升至1.08倍,最终刚度提升至1.12倍。提高配筋率可以提升桥梁抗震性能,也能增加桥梁抗震韧性。2)当桥墩配筋率由0.3%提至0.7%时,在多遇地震下,轻微损伤概率从87.2%降为29.8%;在设计地震下,中度损伤的概率从63.5%降为30.0%;在罕遇地震下,严重损伤的概率从61.7%降为16.4%。纵筋配筋率可以大幅降低桥墩的损伤概率,提升桥墩的抗震性能。3)在现行铁路规范允许的延性系数为4.8时,3个桥墩均处于严重损伤的阶段。当发生罕遇地震时,3个桥墩出现完全破坏的概率为6.4%、0和1.4%,小剪跨比圆端铁路桥墩在强震作用下具有一定的抗震安全储备。
In order to clarify the seismic damage mechanism of round-ended railway bridge piers with small shear span ratio in the transverse direction.Three sets of quasi-static tests with a scale of 1:8 were conducted using a bridge along a certain railway line in China.The ductility,residual displacement,hysteresis energy consumption,and equivalent stiffness of the hysteretic curves were analyzed.Based on the test results,a fiber section finite element model with OpenSees and endurance time analysis dynamic calculations were conducted.Using the displacement ductility ratio of bridge piers as the damage index.The limit values of displacement ductility ratio between five damage states of no,slight,moderate,severe,and complete damage were defined based on the four key points observed in the tests.The damage development process of bridge piers was analyzed through fragility analysis.The research results are drawn.1)The reinforcement ratio has been increased from 0.3%to 0.7%,the bearing capacity of the bridge pier has been increased by 1.37 times,the ultimate displacement has been increased by 1.22 times,the final residual displacement has been increased by 1.55 times,the dissipated energy has been increased by 1.80 times,the initial stiffness has been increased by 1.08 times,and the final stiffness has been increased by 1.12 times.Improving the reinforcement ratio can improve the seismic performance of bridges.2)When the reinforcement ratio of bridge piers is increased from 0.3%to 0.7%,the probability of minor damage under frequent earthquakes decreases from 87.2%to 29.8%.The probability of moderate damage under design earthquakes has decreased from 63.5%to 30.0%.Under rare earthquakes,the probability of severe damage has decreased from 61.7%to 16.4%.The longitudinal reinforcement ratio can significantly reduce the probability of damage to bridge piers and improve their seismic performance.3)When the ductility coefficient allowed by current railway regulations is 4.8,all three bridge piers are in the stage of severe damage.When a rare earthquake occurs,the probability of complete failure of the three bridge piers is 6.4%,0.0%,and 1.4%.Small shear span ratio circular end railway bridge piers have a certain seismic safety reserve under strong earthquake action.
作者
沈林白
洪彧
周志达
王涵玉
蒲黔辉
文旭光
SHEN Linbai;HONG Yu;ZHOU Zhida;WANG Hanyu;PU Qianhui;WEN Xuguang(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Guangxi Key Laboratory of International Join for China-ASEAN Comprehensive Transportation,Nanning University,Nanning 530000,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2024年第1期228-240,共13页
Journal of Railway Science and Engineering
基金
四川省科技计划(2021YJ0054)
广西科技计划(桂科AA21077011)
中央高校基本科研业务费−科技创新项目(2682022CX003)。
关键词
圆端形桥墩
小剪跨比
拟静力试验
弯剪破坏
易损性
round-ended pier
low span ratio
quasi-static test
flexure-shear damage
fragility
