同济大学学报（自然科学版）2013，Vol.41Issue(2)：173-178,6.DOI:10.3969/j.issn.0253-374x.2013.02.003
预应力桥梁竖向振动特性和地震反应分析
Vertical Dynamic Characteristics and Seismic Responses of Prestressed Bridges
摘要
Abstract
Based on the modal perturbation method and the mode superposition method, an approach is established for the vertical seismic response analysis of the prestressed bridges. Several problems met in the vertical seismic response analysis of the prestressed bridge are illustrated by a case study of two simply-support prestressed bridges. Some conclusions are drawn on the basis of the numerical results. The natural frequencies increase when the preloading is applied to the bridge. The preloading effect mainly focuses on the lower natural frequencies and the effect becomes smaller when the modal order is higher. The fundament frequencies of the prestressed bridges with 20 m and 32 m span increase respectively by about 5.3% and 6.3% and its fifth modal frequency only increases by about 1 %. The moments of the middle-span section of the prestressed bridges decrease by about 30% and 25% under the excitation of site ground wave. The contributions of high-order modes can be neglected for the vertical seismic responses of the bridges. The ratio factors of the vertical seismic response in the total response of the middle-span section moment of the prestressed bridges are 24.56% and 26.15% when earthquake fortification intensity is at level 7, and 38. 93% and 41. 46% when earthquake fortification intensity is at level 8. This means that the influence of the vertical responses should be taken into consideration in the seismic design of the prestressed bridges.关键词
预应力桥梁/自振特性/竖向地震反应/模态摄动法Key words
pretressed bridge/ natural vibration characteristics/ vertical seismic response/ modal perturbation method分类
建筑与水利引用本文复制引用
楼梦麟,洪婷婷,李强..预应力桥梁竖向振动特性和地震反应分析[J].同济大学学报（自然科学版）,2013,41(2):173-178,6.基金项目
国家自然科学基金(90915011) （90915011）
