【摘要】 采用大型通用有限元软件ANSYS,建立南京大胜关长江大桥主跨的连续钢桁架拱桥的有限元模型,运用反应谱分析法对全桥结构进行地震响应分析。选用经过加速度幅值调整的El-Centro地震波作为输入地震波,进行大跨度连续钢桁架拱桥一致激励下以及4种不同波速地震行波作用下的全桥结构内力和位移时程响应分析。分析结果表明:南京大胜关桥的整体结构较柔,采用反应谱法计算地震波作用下的桥梁地震响应和采用时程分析法得到的一致激励和多点激励下的桥梁地震响应差别较大,多点激励下的横桥向和竖向地震位移响应是一致激励地震时程计算得到的位移响应的2~3倍;在地震波波速为500或1 000 m.s-1时,桥梁结构关键位置杆件的弯矩达到最大。因此,在进行大跨度拱桥的地震响应动态时程分析时,应该考虑多点激励,以反映桥梁结构在真实地震作用下的实际受力状态和变形性能。更多还原

【Abstract】 The finite element model for the main span of continuous steel truss arch bridge of Nanjing Dashengguan Yangtze River Bridge on Beijing-Shanghai high-speed railway is established with large general FE software ANSYS.The seismic response of the bridge structure is analyzed by the response spectrum method.Then,by taking the amplitude-adjusted El-Centro earthquake acceleration as the input wave,the seismic responses of the long-span continuous steel truss arch bridge under uniform excitation,and the time history responses of displacement and internal force of the main bridge under traveling seismic waves with four different speeds are obtained.The analysis results indicate that the structure of Nanjing Dashengguan Yangtze River Bridge is rather flexible.The seismic responses obtained by the spectrum analysis and the time history analysis under uniform excitation and multiple-point excitations are quite different.The lateral and vertical displacement responses obtained by time history analysis considering the traveling wave effect are two or three times more than the displacement responses under uniform excitation.The bending moments of structural members at key location of bridge may reach the maximum value when the speed of earthquake wave approaches at 500 or 1 000 m·s-1.Therefore,the multiple-point excitations should be considered in the seismic response analysis for long-span arch bridge to reflect the true force-bearing and deformation behaviors of the bridge under earthquake action.更多还原