动力荷载对波形钢腹板连续梁桥应力影响研究

Influence study of dynamic load on continuous beam bridge of corrugated steel web

波形钢腹板PC组合连续梁桥被广泛应用于我国桥梁建造中,然而目前针对波形钢腹板应力的研究主要以静力均布车道荷载为主。为研究移动车辆荷载过桥的动力效应,本文依托四川平武涪江特大桥,通过有限元动力分析计算移动车辆荷载下桥梁的动力挠度及振动响应,同时利用频谱分析桥梁纵向动应力的大小及分布情况,讨论车速及车辆编组对波形钢腹板PC桥梁动应力的影响。结果表明:多跨桥梁结构不同跨主梁的竖向动力响应与其对应的竖弯基频紧密相关;当车速为40~80 km/h时,桥梁结构动力位移和加速度响应符合实际规律;车辆加载频率占桥梁振动响应的主导作用,当车辆行驶至主跨跨中截面附近时,主梁纵向动应力响应出现最大值。

PC composite continuous beam bridge with corrugated steel webs is widely used in bridge construction in our country.However,at present,the research on the stress of corrugated steel webs is mainly based on static uniformly distributed lane load.In order to consider the dynamic effect of the moving vehicle load across the bridge,based on the project of Fujiang Bridge in Pingwu,Sichuan Province,the dynamic deflection and vibration response of the bridge under the moving vehicle load are calculated through the finite element dynamic analysis,the magnitude and distribution of the longitudinal dynamic stress of the bridge are further studied through the frequency spectrum,and the influence of vehicle speed and vehicle formation on the dynamic stress of the corrugated steel web PC bridge is discussed.The results show that the vertical dynamic response of the main girder with different spans of the multi-span bridge is closely related to the corresponding vertical bending fundamental frequency,and the dynamic displacement and acceleration response of the bridge structure accord with the actual law when the vehicle speed is 40~80 km/h.Through the spectrum analysis,it is found that the vehicle loading frequency plays a leading role in the vibration response of the bridge;when the vehicle runs near the middle section of the main span,the longitudinal dynamic stress response of the main beam appears the maximum.