【作者】 杨光；

【导师】 杨勇；

【作者基本信息】 哈尔滨工程大学 ， 力学， 2024， 硕士

【摘要】 随着我国经济和交通运输需求的快速提升,在西部多山或高原地区,大量交通建筑基础设施相继建成并投入使用,而桥梁作为广泛应用于连通山区峡谷等复杂地形的重要基础设施,更是最关键的交通枢纽之一。地震是我国西部地区面对的主要自然灾害之一,这对大跨桥梁在复杂地形环境下的抗震性能提出更高的要求,因此,采用有限元隐式动力学方法研究峡谷地形大跨桥梁的动态响应问题具有重要的意义。本文构建了弧形峡谷地形及多跨桥梁的数值模型,应用黏弹性人工边界和地震动输入方法对弧形峡谷多跨连续桥在不同地震波源类型、不同入射角度和不同入射波频率因素影响下的力学行为进行数值模拟;在简化了土-结构相互作用下,将地形地表地震动时程作为桥墩支承点处的地震动输入,分析了峡谷地形效应对多跨连续桥地震响应的影响。数值结果显示峡谷场地会对不同类型的地震波产生不同程度的地形效应,对地表及峡谷表面地震动的影响明显;随入射角度的增加,峡谷地形地表对地震波的散射更加复杂,迎波面一侧的地表地震动在入射波频率的变化下始终大于背波面一侧。峡谷桥梁的主梁及墩顶的动态响应对入射角度和入射波频率反应敏感,不同入射角度下主梁节点位移的最大值和危险位置均有差异。综合对比分析弧形峡谷多跨连续桥在地震横波(SV波和SH波)及纵波(P波)作用下的动态响应问题以及考虑到混凝土桥梁抗压不抗拉的性质,以平面内剪切波(SV波)和纵波(P波)入射下的瞬态响应为依据加强其抵抗性能够提高峡谷桥梁的安全性。本文研究结果,可为考虑地形效应的大跨桥梁结构抗震设计提供理论参考。更多还原

【Abstract】 With the rapid development of Chinese economy and transportation demand,in the mountainous or plateau areas in the west,a large number of transportation infrastructure has been built and put into use,and bridges,as an important infrastructure widely used in connecting mountainous valleys and other complex terrain,are one of the most critical transportation hubs.Earthquake is one of the main natural disasters in western region of China,which proposes higher demands for the seismic action of long-span bridges in complex terrain environment.Therefore,it is of great significance to use the finite element implicit dynamics method to study the dynamic response of long span bridge in canyon terrain.In this paper,a numerical model of arcuated canyon topography and multi-span bridge is constructed,and the mechanical behavior of arcuated canyon multi-span continuous bridge under the influence of different seismic source types,different incident angles and different incident wave frequencies is simulated by using viscoelastic artificial boundary and ground motion input methods.Under the simplified soil-structure interaction,the seismic response of multi-span continuous bridge is analyzed by using the time history of topographic ground motion as the input of ground motion at pier support points.The numerical results show that the canyon site will produce different topographic effects on different types of seismic waves,and the effects on the ground motion of the surface and the canyon surface are obvious.With the increase of incidence angles,the scattering of seismic waves by the surface of the canyon terrain becomes more complicated.The ground motion on the side of the projecting plane is always greater than that on the side of the shadow plane with the change of incident wave frequency.The dynamic response of main beam and pier top of canyon bridge is sensitive to incident angles and wave frequency,and the maximum displacement and dangerous position of main beam joints are different at different incident angles.The dynamic response of multi-span curved canyon continuous bridge under the action of shear wave(SV wave and SH wave)and longitudinal wave(P wave)is analyzed comprehensively and considering the properties of concrete bridge under compressive and nontensile,and the transient response under in-plane shear wave(SV wave)and longitudinal wave(P wave)is taken as the basis to strengthen its resistance performance to improve the safety of canyon bridge.The results of this paper can supply theoretical reference for seismic design of long-span bridges considering terrain effects.更多还原