混凝土拱桥拱上建筑轻型化研究

Research on Reducing the Weight of Spandrel Structure for the Concrete Arch Bridges

制约混凝土拱桥向更大跨度发展的主要问题是结构自重大和施工架设困难。为提高混凝土拱桥的竞争力和促进该桥型的进一步发展,以420 m跨径的重庆万州长江大桥为工程背景,通过桥道系连续化和采用组合结构代替原有混凝土结构等方式来进行混凝土拱桥拱上建筑轻型化研究。与原设计在静力性能和地震响应分析的比较结果表明,桥道系连续化对减轻拱上建筑结构自重的效率较低,其静力性能与抗震性能提高也不大;而采用组合结构可使得拱上建筑结构自重减轻35%,拱脚轴力和弯矩分别降低了16%和17%,三向地震作用下的拱脚横向弯矩和拱顶横向位移分别减小了13%和18%,拱脚纵向弯矩、轴力分别降低了45%和44%,具有可行性。

Development of long-span RC arch bridges are restricted by two critical factors,the heavy self-weight and the difficult construction techniques.In order to advance the competitiveness and further application,researches on reducing the self-weight of spandrel structures of RC arch are conducted by either making the deck from simply supported to continuous or utilizing composite structure in Wanxian Yangtze River Bridge with a main span of 420 m.The results of the trial design by using composite structure show that with comparison of the original bridge the self-weight of spandrel structure is reduced by 35%,and the axial force and bending moment of arch springing is decreased by 16% and 17%.Simultaneously,the bending moment seismic response of arch springing in longitudinal and transverse direction reduce 45% and 13% under the three-directional ground motions and the axial force of arch springing in longitudinal direction reduce 44% and the deflection of arch crown in the transverse direction reduce 18%.The composite structure is superior to the continuous girder solution in the static and seismic performance which is feasible in practical application.