基于“设计标准”的大型渡槽动力计算与隔减震研究

Research on seismic isolation and reduction of large aqueduct and its dynamic calculation based on“Design Standards”

以“设计标准”为圭臬,分析了大型渡槽动力学分析的几个关键技术的实现途径,并以某高烈度区待建8跨大型渡槽为研究对象,把高阻尼橡胶支座应用到渡槽结构的隔减震体系中,考虑了槽内水体与渡槽的动力相互作用,建立了大型渡槽槽体-水体-支座-槽墩-基础等结构体系的动力有限元模型。同时,采用可调节阻尼等效双线性恢复力模型对高阻尼支座进行模拟,并采用傅氏逆变换拟合了符合场地特性的人工地震波并验证了其合理性,改进了Wilson-θ法并对渡槽体系进行了动力学求解,给出了大型渡槽的位移、变形、支座滞回性能及槽间横向错动位移等动力响应,分析了高阻尼支座的隔减震效果,并结合大型渡槽结构体系的动力特性和反应谱特征,分析高阻尼支座的隔减震机理。同时,考虑到1级大型渡槽的重要性,推荐渡槽结构在承载能力极限状态计算及正常使用极限状态校核时,按分项系数的原则,叠加渡槽结构全时域全场域的最值动力响应,以期促进待建和已建渡槽工程的实施与安全运营。

Taking the“Design Standards”as a guideline,the realization of several key technologies for dynamic analysis of large aqueducts is analyzed,and an 8-span large-scale aqueduct to be built in high intensity seismic area is taken as the research object,applying the high damping rubber bearing to the isolation and damping system of aqueduct structure simultaneously,considering the dynamic interaction between water body and aqueduct structure system,the dynamic finite element model of structural system which constitute of aqueduct body,water body,support and foundation are established.The equivalent bilinear resilience model with adjustable damping is used to simulate the high damping bearing,and the inverse Fourier transform was used to fit the artificial seismic wave conform with the site characteristics and to verify its rationality,improving the Wilson-θmethod and using it to solve the dynamics of the aqueduct system.The dynamic responses of large aqueduct,such as displacement,deformation,bearing hysteretic performance and transverse alternate displacement between aqueducts,are given,the isolation and damping effect of high damping bearing is analyzed,and the vibration isolation mechanism of high damping bearings is analyzed in combination with the dynamic characteristics and response spectrum characteristics of large aqueduct structure system.At the same time,considering the importance of grade 1 large aqueduct,it is recommended to apply the principle of partial coefficient to superpose the maximum dynamic response of the whole aqueduct structure in the entire time-domain and the full-field domain when calculating the ultimate bearing capacity of the structure and checking the serviceability limit state.It can be expected that the research results of this paper can promote the implementation and safe operation of the aqueduct projects which are going to be built and the already finished ones.