台风气候大跨度桥梁风振响应研究

Investigation of wind-induced performance about long-span bridges under typhoon climate

以中国东南部沿海台风多发区3类典型大跨度桥梁为例,即长江三角洲区域舟山群岛西堠门大桥,上海长江大桥和珠江三角洲区域广州新光大桥,运用Monte-Carlo随机模拟算法,结合大量台风历史实测数据,再现了台风气候条件下桥位工程场地风环境参数取值特点;考虑桥梁结构几何非线性效应、多种气动力荷载共同作用下的平均风及瞬时风攻角效应,由时域有限元计算方法比较了良态与台风气候条件下大跨度桥梁风振响应。利用大气边界层风洞被动紊流发生装置,再现了台风条件下新光大桥全桥气弹模型流场特征和风振响应过程,基于中跨拱肋二维节段模型高频天平测力试验识别了台风强紊流条件下气动导纳函数,进一步精细化地分析了台风条件下新光拱桥风致振动响应特点。

Three typical long-span bridges in typhoon-prove regions nearby southeast coastline of China were selected, which are Xihoumen suspension bridge and Shanghai Yangze River cable-stayed bridge in Yangze River Delta Economy zones, Guangzhou Xinguang long-span arch bridge in Pearl River Delta Economy zones, and its wind field characteristics under typhoon conditions were illustrated with the help of Monte-Carlo typhoon stochastic simulation algorithm and long term typhoon observation records from meteorological stations nearby the above long-span bridges. Considering structural geometrical non-linear effects, stochastic wind angle effects from several aerodynamic loadings, wind-excited responses about the longspan bridges under normal and typhoon climate modes were compared systematically with time-domain FEM computations. Using passive turbulent generators in TJ-3 wind tunnel, 1 ： 200 reduced-scale typhoon field simulation and wind-induced responses about Xinguang arch bridge aero-elastic models were conducted, then aerodynamic admittance function about its midspan lattice arch section under higher turbulent flow condition of typhoon was identified by means of high-frequency forcemeasured balance, so the improved dynamic responses under typhoon condition with higher precision can be obtained. Which be of the same trend and response characteristics under various incoming wind velocity as wind tunnel test results.