近场地震下深水桥墩响应特性及动水效应计算方法检验  

Response property of deep-water bridge pier under near-fault earthquakes and inspection of calculation methods of hydrodynamic effect

作　　者：江辉[1] 王宝喜 白晓宇[1] 朱晞[1] 曾聪[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]中国市政工程西北设计研究院有限公司,甘肃兰州730099

出　　处：《长安大学学报（自然科学版）》2016年第4期48-57,共10页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(51378050);高等学校学科创新引智计划项目("111计划")(B13002);国家山区公路工程技术研究中心开放基金项目(gsgzj-2011-12);中央高校基本科研业务费专项资金项目(2014JBM044)

摘　　要：动水效应是深水桥梁抗震设计中需要考虑的重要问题,而近场地震下深水桥墩的响应特性及合理计算方法亟待研究。以某典型深水桥梁为对象,基于可有效考虑墩-水流固耦合效应的完全数值计算方法,建立其等效单墩模型。首先讨论了水域范围对结构自振频率计算结果的影响,然后分析了不同水深下桥墩自振特性及脉冲型近场地震下的响应特征,并检验了几种代表性的解析-数值方法的准确性。研究结果表明:当水域宽度达到桥墩直径的10倍时,自振频率计算结果保持稳定;桥墩自振频率随水深增大而减小,桥墩完全被水淹没时前3阶自振频率分别比无水时减小了5.3%、12.2%和17.9%;不同方法下各阶频率的误差率随水深增大总体呈增大趋势,日本规范所得频率偏大,最大误差率超过20%,Morison方程法所得频率偏小,辐射波浪理论、中国铁路规范所得频率值与流固耦合数值法接近;近场地震下,桥墩弯矩、剪力和位移响应比无水时分别增大了22%、23%和20%,Morison方程法计算结果偏大,其最大误差率超过6%,日本规范计算结果偏小,最大误差率接近-5%,辐射波浪理论、中国铁路规范及李乔-杨万理简化公式所得结果与流固耦合完全数值法相吻合,5种方法均可适用于一般尺度深水桥梁的抗震设计。研究成果对于近断层区深水桥梁的抗震设计具有借鉴意义。Hydrodynamic effect is an important issue which should be taken into account in seismic design of deep-water bridges, and the response property of deep-water bridge pier under near- fault earthquakes and its reasonable computation method needs to be studied. Therefore, taking a typical deep-water bridge as research subject, this paper built the equivalent pier model based on complete numerical method considering fluid-structure interaction. The influence of water range on stability of results was analysed firstly. Then the vibration and response characteristics of the deep-water pier excited by impulsive near-fault ground motions were discussed. Furthermore, the accuracy of several typical analytical-numerical methods was checked. The results show that the vibration frequency tends to be stable when the water width is 10 times of pier＇s diameter. The vibration period and dynamic response of pier is amplified by hydrodynamic effect, and this influence becomes more significant with the increase of water depth. The first three vibration periods of pier with full-water around increase by 5.3%, 12.2% and 17.9%, while the maximum bending moment, shear force and displacement increase by 22%, 23% and 20% respectively under near-fault earthquake. The error rates of different methods vary with the change of water depth. The calculated response by Morison equation method is larger than that by complete numerical method, and the error rate is beyond 6 %, while that by Japanese code is smaller and its error rate is close to -5%. The calculated results by radiation wave theory, Chinese railway code and Li Qiao-Yang Wan-li＇s formula are quite close to that by complete numerical method, which means these methods are applicable to deep-water bridge of usual sizes. The above research results could provide reference for seismic design of deep-water bridge near active fault zone. 2 tabs, 9 figs, 21 refs.

关 键 词：桥梁工程 深水桥梁 等效单墩 流固耦合 解析-数值算法 近场地震 附加质量 动力响应 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]