水电站地面厂房越来越多采用网架屋面,为研究网架支承方式及其有限元模拟方法对厂房地震响应的影响,运用ANSYS软件建立了5种有限元模型,采用时程法分析了厂房在顺河向地震加速度下的响应。研究表明:网架对厂房下部结构影响小,对上部结构影响大,将网架简化为连杆支撑时计算结果与实际相差较大,不建议采用连杆对网架进行简化模拟;在缺少网架资料,并且网架与下部支承的连接方式为一端固定铰支座一端滚轴支座时,可以采用不考虑网架的简化模型计算;网架为抗震薄弱部位,且地震响应受下部支承影响大,网架与下部支承一端为固定铰支座一端为滚轴支座的连接方式,相比较于两端均为固定铰支座的连接方式,顺河向抗震性能明显较好,但考虑静力组合作用后网架的轴力更大,应慎重选取连接方式。
Nowadays grid roof is used more and more widely in ground hydropower house. In order to study the influence of grid supporting modes and its FEM simulation to the seismic response of power house, five FEM models are built by ANSYS, and seismic response under downstream directional earthquake acceleration of the power house are calculated. The results show that the influence of grid to superstructure is bigger than substructure, simplifying grid into link between the upright column gives a result disagree with reality, so simplifying grid into link is not suggested; when lacking the structural information of grid, the simulation model without grid can be used in calculation of power house with fixed hinges at one end and rolling hinges at the other end supporting mode grid roof; grid structure is the weak part in aseismic behavior, its seismic response is greatly influenced by the supported structure, compared with fixed hinges supporting mode at each end of the grid, when the supporting mode is fixed hinges at one end and rolling hinges at the other end, the grid has much better aseismic behavior in downstream direction, but it's axial stress is larger after adding the static load combination, so the supporting mode of grid roof should be chosen cautiously.