工作桥对进水塔整体结构的抗震性能影响研究

Influence of working bridge on seismic performance of integral system of intake towers

地震作用下,进水塔与工作桥、库水、地基的相互作用复杂。通过建立塔身主体结构-启闭机房-工作桥-地基-库水整体有限元模型,基于势流体理论模拟结构与库水的相互作用,采用黏弹性人工边界考虑地基辐射阻尼,研究结构与库水、工作桥和地基的动力相互作用对进水塔整体体系自振特性和地震动力响应的影响。结果表明:在正常蓄水位下,工作桥的存在会使进水塔结构的顺流向位移最大减小25.15%,加速度最大减小14.33%,进水塔关键点最大拉应力降幅可达12.0%以上;考虑地基的辐射阻尼效应时,进水塔结构的动力响应明显减小,其关键点的最大拉应力降幅可达40%以上。相比工作桥,地基辐射阻尼效应对进水塔地震作用下动水压力、加速度、位移和应力响应的影响更加显著。

The interaction between the intake tower,working bridge,reservoir water and foundation is complex under seismic actions.The integral finite element model of the tower body-hoist chamber-working bridge-foundation-reservoir water was established,with which the interaction between the structure and reservoir water was simulated based on the potential fluid theory,and the foundation radiation damping effect was investigated using the viscoelastic artificial boundary.In turn,the effect of dynamic interactions between structure,reservoir water,working bridge and foundation on the natural vibration characteristics and seismic response of the integral intake tower system was studied.The results show that the downstream displacement and acceleration of the intake tower can be reduced by 25.15% and 14.33% respectively,and the maximum tensile stress of key points of the intake tower can be reduced by more than 12.0%,with the presence of the working bridge at normal water level.The dynamic response of the intake tower structure is obviously reduced when considering the foundation radiation damping effect,and the maximum tensile stress of the key point can be reduced by more than 40%.Compared with the working bridge,the foundation radiation damping effect has a more significant influence on the hydrodynamic pressure,acceleration,displacement and stress response of the intake tower under seismic actions.