激励方向对库区上承式深水拱桥地震响应影响分析

Analysis of influence of incentive direction on seismic response of upward deep water arch bridge in reservoir area

位于高烈度地区的库区上承式拱桥,在地震作用时因受到动水压力作用,其地震响应与普通上承式拱桥(无水时)差异较大。库区拱桥在地震作用下,动水压力与结构的迎水面积有关,而随着地震激励方向的不同,作用于结构上的动水压力不尽相同,导致结构的地震响应差异很大。目前工程界对地震激励方向的研究主要集中于斜交桥和曲线桥,而对库区深水拱桥的地震激励方向研究较少。本文以永春河大桥为依托工程,采用有限元建模计算在不同淹没深度下的库区拱桥的动力特性,研究不同地震激励方向下动水压力对拱圈内力和拱顶位移的影响规律。

The upper arch bridge in the reservoir area in the high intensity area is affected by the dynamic water pressure during the earthquake,and its seismic response is quite different from that of the ordinary upper arch bridge(when no water).Under the action of earthquakes,the hydrodynamic pressure in the reservoir area is related to the water-facing area of the structure.With the different excitation directions of the earthquake,the hydrodynamic pressure acting on the structure is not the same,resulting in a large difference in the seismic response of the structure.At present,the research on the direction of seismic excitation is mainly focused on the skew bridge and the curved bridge,while the research on the seismic excitation direction of the deepwater arch bridge in the reservoir area is less.Based on the Yongchun River Bridge,the dynamic characteristics of the arch bridges at different submerged depths are calculated by finite element modeling.The effects of hydrodynamic pressure on the internal forces of the arches and the displacement of the domes under different seismic excitation directions are studied.