浅谈高地震烈度区高墩抗震设计

Brief Discussion on Seismic Design of High Piers in High Seismic Intensity Areas

某项目为位于地震烈度8度区域的公路桥梁。桥梁上部结构采用40m跨径T梁,下部桥墩在35~80m高度范围内分别采用了实心板式桥墩及两种类型的空心薄壁桥墩。为了验证项目中这3类高墩的桥梁结构在地震作用下的安全性,分别对此3类桥墩进行了抗震分析验算。该桥采用了减隔震设计及非线性时程分析方法进行抗震分析。通过分析计算及验算后,全桥均采用高阻尼抗震橡胶支座以更好地控制位移。在此基础上,建议在施工允许的条件下对上半部分的墩身尺寸及配筋进行优化;建议对部分桩基间距进行优化,并充分重视基岩地区桩基抗拔及承载力的验算。

A project is a highway bridge located in the area of seismic intensity 8.The 40 m-span T-beam is used for the superstructure of the bridge,and the solid slab piers and two types of hollow thin-walled piers are used for the lower piers within the height range of 35~80 m.In order to verify the security of the three types of high pier bridge structures in the project under the action of the earthquake,the seismic analysis and check calculation of the three types of piers are carried out respectively.The seismic isolation design and nonlinear time history analysis method are adopted for the seismic analysis of the bridge.After analysis,calculation and checking,the high damping seismic rubber bearings are used for the whole bridge to better control the displacement.On this basis,it is suggested to optimize the pier shaft size and reinforcement of the upper half under the condition of allowable construction.It is suggested to optimize the spacing of some pile foundations,and pay full attention to the checking calculation of uplift resistance and bearing capacity of pile foundations in bedrock areas.