摘要
针对跨海桥梁服役期内可能遭受地震、波浪以及冲刷效应影响的问题,开展地震与波浪联合作用下考虑冲刷效应的跨海斜拉桥振动台试验,研究地震与波浪联合作用下冲刷效应对斜拉桥动力特性及关键截面动力响应(加速度、位移和应变)的影响规律。研究表明:随着冲刷深度的增加,斜拉桥自振频率逐渐降低;冲刷深度的增加,降低了桥塔桩基础侧向约束,引起地震与波浪联合作用下桩顶动力响应明显增大,且增幅比其他位置更为显著;边墩墩顶加速度和相对位移均大于辅助墩墩顶,桥墩抗震设计时,应采用不同配筋率和不同的截面尺寸对边墩和辅助墩开展差异化设计;考虑冲刷效应明显增大了地震与波浪联合作用下塔底、边墩和辅助墩墩底等关键截面的应变,相较于无冲刷工况,大冲刷工况下塔底、边墩及辅助墩墩底应变分别增加39%、36%和42%,抗震设计时应高度重视。
In this study,the shaking table tests were carried out on a sea⁃crossing cable⁃stayed bridge under the combined action of earthquake and wave considering scour effects.The influences of scour effects on the dynamic characteristics and the dynamic re⁃sponses(accelerations,displacements,and strains)of the critical sections of the cable⁃stayed bridge were investigated.Test results show that the natural frequency of the cable⁃stayed bridge decreases gradually with the increase of scour depth.The increase in scour depth also weakens the lateral restraint of the pile foundation,leading to a significant in⁃crease in the dynamic responses at the pile top under the combined action of earthquake and wave.Both the acceleration and the relative displacement responses at the top of the side pier are larger than those of the auxiliary pier,and hence reinforcement ratios and cross⁃sectional sizes shall differ in the seismic design of the side pier and auxiliary pier.Moreover,scour effects significantly increase the strains of critical sections of the bridge under the combined action of earthquake and wave.Compared to the case without scouring,the strains at the bottom of tower,side pier,and auxiliary pier under severe scour condition increase by 39%,36%and 42%,respectively.Therefore,special attention shall be paid to the scour effects of pile foundation in the seismic design of sea⁃crossing cable⁃stayed bridges.
作者
李忠献
郑庆涛
苏俊省
赵博
Li Zhongxian;Zheng Qingtao;Su Junsheng;Zhao Bo(Key Laboratory of Coast Civil Structure Safety of the Ministry of Education,Tianjin University,Tianjin 300350,China;School of Civil Engineering,Tianjin University,Tianjin 300350,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2024年第10期71-81,共11页
China Civil Engineering Journal
基金
国家自然科学基金(52238012,51427901)。
关键词
跨海斜拉桥
振动台试验
地震-波浪联合作用
冲刷效应
动力响应
sea⁃crossing cable⁃stayed bridge
shaking table test
combined action of earth⁃quake and wave
scour effect
dynamic response
