【作者】 焦驰宇； 龙佩恒； 王毅娟；

【Author】 JIAO Chi-yu,LONG Pei-heng,WANG Yi-juan (Beijing University of Civil Engineering and Architecture,No.1 ZhanLan Road westcity district of Beijing city,100044 )

【机构】 北京建筑工程学院；

【摘要】 要在抗震概念设计阶段获得大跨度漂浮体系斜拉桥主塔地震弯矩的合理值,必须对主塔弯矩的主要贡献振型进行研究。在对Ⅲ类场地规范反应谱长周期成分合理修正的基础上,通过对三座不同跨径的大跨斜拉桥工程实例的反应谱分析,计算出主塔弯矩的主要贡献振型的贡献百分比。对不同修正方法和不同跨径引起主塔弯矩主要贡献振型的变化进行了研究,同时对千米级斜拉桥不同主塔抗推刚度引起主塔弯矩主振型贡献百分比的变化进行了研究,分析了纵飘振型贡献百分比变化的转折点。结果表明:随着斜拉桥跨径的增大,主塔地震弯矩的主要贡献振型从纵飘振型变成主塔的一阶纵弯、二阶纵弯振型;千米级大跨斜拉桥的主塔抗推刚度较小时,主塔塔底弯矩由纵飘振型和主塔纵弯高阶振型共同引起。更多还原

【Abstract】 Abstract:.In order to get reasonable tower base seismic bending moment of cable-stayed bridge adopted floating system in the conceptual seismic designs,the dominant vibration modes contributory to the seismic moment must be studied.Based on the reasonable modification of normal acceleration response spectra(ARS) of type III,the response spectra analysis of three typical long-span cable-stayed bridges were done in this paper,the contribution percentage of dominant vibration modes were calculated also.Transformation of the dominant vibration modes calculating by different modified ARS and different span is discussed.Transformation of contribution percentage of dominant modes of super-long-span cable-stayed bridge based on different tower push stiffness is studied,the turning point of the first-order mode contribution percentage was found.It can be concluded that the dominant vibration modes contributory to the seismic moment of main tower is turned from the floating mode into the first and second-order tower bending mode as the span increased.For super-long-span cable-stayed bridges with small tower push stiflhess,tower base seismic bending moment usually is activated mostly by floating mode and the high-order tower bending mode更多还原