地震和波浪联合作用下斜拉桥随机动力分析方法  

Stochastic dynamic analysis method for a cable-stayed bridge under combined actions of earthquake and waves

作　　者：孟思博 丁阳[1,2] MENG Sibo;DING Yang(School of Civil Engineering,Tianjin University,Tianjin 300350,China;MOE Key Lab of Coast Civil Engineering Structures and Safety,Tianjin 300350,China)

机构地区：[1]天津大学建筑工程学院,天津300350 [2]滨海土木工程结构与安全教育部重点实验室,天津300350

出　　处：《振动与冲击》2020年第17期194-202,共9页Journal of Vibration and Shock

基　　金：国家重点基础研究发展“973”计划项目(2011CB013606);国家自然科学基金面上项目(51378343)。

摘　　要：分别采用Morison方程、辐射波浪理论和绕射波浪理论求解桩基、承台所受动水压力和波浪力,考虑行波效应、空间相干效应和局部场地效应,基于虚拟激励法,建立了多维多点地震和波浪联合作用下斜拉桥随机动力分析方法。采用蒙特卡罗法计算了考虑、不考虑荷载非线性时的结构响应,通过比较计算结果验证了所建立方法的适用性;分析动水压力和波浪力对斜拉桥随机地震响应均方根的影响,研究了斜拉桥随机响应功率谱密度分布趋势和变化规律。结果表明:该方法可以考虑荷载随机性,计算多维多点地震和波浪联合作用下斜拉桥响应;动水压力刚性附加质量是导致斜拉桥水下结构纵向内力增大的原因;动水压力和波浪力对桥塔水下结构地震响应的影响随场地条件改变,地震输入能量分布在高频域时,动水压力和波浪力对桥塔水下结构影响更大。Hydrodynamic pressure and wave force exerted on pile foundations and bearing platforms were solved with Morison equation,the radiation wave theory and the diffraction wave theory,respectively.Considering traveling wave effect,spatial coherence one and local site one,based on the virtual incentive method,the stochastic dynamic analysis method for a cable-stayed bridge under combined actions of multi-point earthquake and waves was proposed.Monte Carlo method was used to calculate effects of load nonlinearity on structural response.The applicability of the proposed method was verified through comparing its calculation results with those using Monte Carlo method.Effects of hydrodynamic pressure and wave force on root mean square of stochastic seismic response of a cable-stayed bridge were analyzed.The distribution trend and variation law of random response power spectral density of the cable-stayed bridge were studied.Results showed that the proposed method can consider the randomness of load,and calculate stochastic dynamic response of a cable-stayed bridge under combined action of earthquake and wave;hydrodynamic pressure’s rigid added mass can cause longitudinal internal force of the bridge’s underwater structure to grow;effects of hydrodynamic pressure and wave force on seismic response of the bridge tower’s underwater structure vary with variation of site conditions;when seismic input energy is distributed in a high frequency range,effects of hydrodynamic pressure and wave force on seismic response of the bridge tower’s underwater structure are larger.

关 键 词：斜拉桥 多点地震 动水压力 波浪 联合作用 随机响应 

分 类 号：TH212[机械工程—机械制造及自动化] TH213.3