大跨度汽机房屋盖风振系数研究

Study of wind-induced vibration factor for large-span steam turbine building roof

根据风洞试验获得的屋盖表面风压及风压时程,对A类风场某电厂双坡大跨度汽机房屋盖结构进行风致抖振的非定常频域计算分析,采用位移响应计算风振系数,为屋盖抗风设计提供依据.考虑了机组布置、屋盖类型及阻尼比变化对风振系数的影响,得到18组风振计算结果.结果表明,周边建筑物对风振响应有影响,独立厂房时,风振响应最大;屋盖的结构型式对风振系数影响不大;大部分节点响应以背景响应为主,阻尼比的变化基本没什么影响;处于屋面边缘的节点,阻尼比的变化有一定的影响;对于边缘部位的屋盖受力杆件,要考虑风下压力的作用.

Based on the surface wind pressure and wind pressure time-history obtained by wind tunnel test,a non-steady frequency domain analysis caused by the wind buffeting on big span gable roof of a power plant steam turbine building at category A of terrain is carried out to provide the design basis of roof.Calculating the wind vibration factors by displacement response and getting 18 groups of data,arrangement of units,type of roofs and varieties damping ratios which affecting wind vibrating are considered.The results show that the wind vibration will be affected by the circumjacent building and be maximal for single building;the structural types of the roofs rarely affect the wind vibration;most node responses is mainly background response;and the varieties damping ratios effect is small;the varieties damping ratios will give a certain effect for the nodes at the edge of the roof;the wind pressure down onto the roof should be considered for the members at the edge of the roof.