摘要
用相位谱表征地震动频率的非平稳特性,用相干函数表征地震动空间变化的不相干效应,采用随频率变化的等效相速度代替随意给定的视波速表征地震动的行波效应,生成了具有强度和频率非平稳特性的多点地震动。将这种考虑时间和空间变化的地震动在水平方向作用于5跨高墩连续刚构曲线桥桥墩基础处,计算了墩顶位移及墩底内力,分析了大跨曲线桥多点输入中不相干效应和行波效应对结构响应的影响。结果表明考虑地震动空间变化特性的墩顶位移峰值多数显著大于一致激励。相干性显著增大了激励方向墩底的动内力,但对拟静力位移差动产生的内力有时增大有时减小,两者叠加后的总内力峰值多数大于一致激励。
When calculating the multi-point ground motions with non-stationary intensity and frequency,a phase spectrum is introduced to consider the non-stationary properties of the frequency contents,a coherence function is selected to consider the incoherence effect,and an equivalent phase velocity varying with the frequency of earthquake wave,rather than an arbitrary apparent velocity,is adopted to consider the traveling wave effect.The synthetic non-stationary ground motions can consider the temporal and spatial variation,which are used as inputting data for a curved continuous rigid-framed bridge with five spans and high piers in horizontal directions.The pier-top displacements and the pier-bottom internal forces of the bridge are calculated.The incoherence effect and the traveling wave effect are discussed.The results are concluded that when the spatial variation of the seismic ground motion is considered,the displacements of the majority piers are larger than that of uniform excitation,and also indicated that in the excitation direction the dynamic internal forces of the piers are increased apparently while the quasi-static forces caused by differential ground motions may be increased or decreased,and when the quasi-static response is superimposed with the dynamic one,the total internal forces of majority piers are larger than that of uniform excitation.
出处
《世界地震工程》
CSCD
北大核心
2010年第3期67-73,共7页
World Earthquake Engineering
基金
国家自然科学基金项目(50678001)
北京市教育委员会科技发展计划重点项目(kz200710009005)
关键词
地震响应
相位差谱
多点激励
曲线桥
seismic responses
phase spectrum
multi-support excitations
curved bridge
