高墩连续刚构桥双悬臂状态等效风荷载的简化计算

Simplified Calculation of Equivalent Wind Loads of High Pier Continuous Rigid Frame Bridge in Double Cantilever State

基于高墩连续刚构桥双悬臂状态的特点及横桥向一阶振型,考虑平均风荷载与结构脉动风荷载背景响应及共振响应,给出了方便工程应用的计算墩底横桥向弯矩和剪力等效风荷载及风载内力的简化计算方法。为验证简化计算方法的精度,分别采用抖振频域分析方法及简化计算方法对2个典型算例进行了分析,并与现行规范静阵风系数的结果进行比较。结果表明:简化计算方法具有较好的精度,适于工程应用;若忽略脉动风共振响应的影响,对高墩桥梁其结果将偏小较多;高墩桥梁的桥墩风荷载很大,其对墩底风载内力的影响甚至可能超过主梁,应引起足够重视。

Based on characteristics of high pier continuous rigid frame bridge in double cantilever state and its transverse first order mode shape,considering resonant responses and background responses of average wind loads and structural fluctuating wind loads,a simplified calculation method of equivalent wind loads of transverse bending moment and shear force of pier-bottom and its internal force on high pier continuous rigid frame bridge was given.In order to verify calculated accuracy of the simplified calculation method,buffeting frequency domain analysis method and the simplified calculation method were used to analyze two typical examples.The calculated results by the two methods and static gust factor result of wind-resistant design specification were compared.The results show that the method has good accuracy,and is applicable to engineering application.The results will be far smaller for high pier bridges if resonant responses of fluctuating wind are neglected.The wind load on pier of high pier bridge is big,its influence on internal force of wind load at pier bottom even surpasses the influence of main beam on the internal force.It should induce much attention.