驸马长江大桥非线性静风响应研究

Study of Non-linear Aerostatic Response of Fuma Changjiang River Bridge

驸马长江大桥为主跨1 050m的单跨简支梁悬索桥,主梁采用流线型钢箱梁。为研究该桥非线性静风响应,考虑静风荷载非线性和结构几何非线性,采用增量法与内外双重迭代相结合的方法,分析加劲梁初始攻角、附加攻角、缆索风荷载等因素对静风位移、静风失稳风速及结构动力特性的影响,并将计算结果与1∶80全桥气弹模型风洞试验结果进行比较。结果表明:静风位移计算值低于风洞试验实测值,这是静三分力系数的雷诺数效应造成的;缆索风荷载约占结构总体风荷载的15%,不考虑会低估风荷载;不考虑加劲梁附加攻角会高估静风失稳风速;初始攻角、附加攻角、缆索风荷载对加劲梁静风位移响应影响较大;结构动力特性会随风速改变而改变。

T he stiffening girder of the Fum a Changjiang River B ridge,a single span sim plysupportedgirder suspension bridge w ith a main span of1050m,adopts the stream ed-lined steelbox girder.To study the non-linear aerostatic response of the bridge,the effects of the initial wind attacking angle,additional w ind attacking angle of the stiffening girder and the w ind loads on themain cables on the aerostatic displacem ent,w ind speeds inducing the aerostatic instability of thestructure and the dynam ic properties of the structure w ere analyzed by the com bined use of the incremental m ethod and the internal and external iteration,taking into account both non-linear aerostaticloads and geom etric non-linearity of the structure.T he results of the calculation w ere comparedw ith the values gained from the w ind tunnel tests on the1:80scale aeroelastic model of thefull bridge.T he com parison indicated that the calculated values of the aerostatic displacem ent w erelow er than the m easured data from the w ind tunnel te s ts,due to the Reynolds N um ber Effect ofthe static aerodynam ic force coefficients.T he w ind loads on the main cables accounted for15%ofthe overall w ind loads of the stru ctu re,w ith no consideration of w hich w ould cause the underestimation of the w ind loads.N evertheless,the w ind speeds that w ould cause the aerostatic instabilityof the structure m ight be overestim ated w ithout the consideration of the additional w ind attackingangle of the stiffening girder.A nd the dynam ic properties of the structure vary w ith the fluctuationof the w ind speeds.