基于P-M谱的波浪荷载数值模拟及其对跨海斜拉桥的冲击响应规律研究  

Based on P-M spectrum numerical simulation of wave load and dynamic responses of a cross-sea cable-stayed bridge

作　　者：罗浩[1] 徐楚懿 杨彤麟 郭辉 郭向荣[3] LUO Hao;XU Chu-yi;YANG Tong-lin;GUO Hui;GUO Xiang-rong(School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;Railway Engineering Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China;School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]湖南科技大学土木工程学院,湘潭411201 [2]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081 [3]中南大学土木工程学院,长沙410075

出　　处：《计算力学学报》2023年第4期552-558,共7页Chinese Journal of Computational Mechanics

基　　金：国家自然科学基金(51408217);湖南省自然科学基金(2021JJ30258,2015JJ3066)资助项目。

摘　　要：针对深水桥梁在海洋中面对波浪的冲击问题,以某跨海斜拉桥为例,设定P-M谱为目标谱,依据Welch算法对海浪功率谱进行验证,基于以上理论采用fluent软件建立数值波浪水槽,根据重现期为10年、50年和100年分别计算对应的波高为6.4 m, 7.2 m和9.6 m的波浪力,并将波浪力导入斜拉桥进行动力响应计算。综合分析大桥的动力响应,结果表明,(1)纵桥向波浪力是由横桥向波浪冲击桥墩出现绕射效应而产生,所以斜拉桥所受横桥向波浪力远大于纵桥向波浪力;(2)随着波高的增大,斜拉桥的动力响应峰值逐渐增大,主跨跨中和塔顶动力响应峰值随波高的增长率最快,次边跨跨中动力响应峰值随波高的增长率次之,边跨跨中动力响应峰值随波高的增长率最慢;(3)随着波浪荷载的增大,塔顶横向位移响应增幅显著,塔顶位移响应峰值最大达到0.0598 m。相关研究对大跨度深水桥梁的设计和动力分析有一定的参考意义。To study bridges subjected to wave loads in the ocean,a cross-sea cable-stayed bridge was taken as an example.Based on the P-M spectrum as the ideal wave spectrum,the numerical simulation of wave spectrum was estimated by Welch algorithm.Compared with the original P-M spectrum,it was shown that the simulation result was good.The fitting error of the power spectrum estimation was 1.22%.In order to accurately analyze the wave loads,a numerical wave tank was established by fluent software,and the numerical waveform was well fitted with the theoretical waveform.Therefore,three different wave conditions are set respectively,and the dynamic response results such as displacement and acceleration of different parts of the bridge under wave impact were obtained.The comparative results show that the longitudinal wave forces of the cable-stayed bridge under wave loads were far less than the lateral wave forces,because the longitudinal wave force was mainly caused by the diffraction effect of the lateral wave impact on the bridge.With the increase of wave height,the peak dynamic response of the cable-stayed bridge gradually increased.The growth rate of peak dynamic response in the mid-span and at the tower top were the highest,the growth rate of peak dynamic response in the secondary side span was the second highest,and the growth rate of peak dynamic response in the side span was the lowest.With the increase of wave load,the lateral displacement response of the tower top increased significantly,and the maximum displacement response of the tower top was 0.0598 m.The time history responses of base shear and moment value increased with the increase of wave load.The related research has some reference significance to the design and dynamic analysis of large-span deep-water bridges.

关 键 词：波浪荷载 海浪谱 数值波浪水槽 斜拉桥 动力响应 

分 类 号：U448[建筑科学—桥梁与隧道工程] O353.2[交通运输工程—道路与铁道工程]