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为了方便计算非对称悬索桥的对称竖弯自振基频,采用Rayleigh法分别推导了不考虑和考虑边缆和主塔刚度影响下的非对称悬索桥一阶对称竖弯自振基频的近似计算公式,提出了修正规范公式的非对称结构参数影响因子和计入边缆和主塔刚度的非对称结构参数影响因子,并给出了边缆和主塔刚度对竖向自振基频的影响系数的表达式,最后通过有限元法验证近似公式的精度.研究结果表明:在计算非对称悬索桥竖向自振基频时不能忽略边缆和主塔刚度的影响,计入边缆和主塔刚度影响的实用公式计算结果与有限元法计算结果非常接近,误差为3.3%,能满足工程上对精度的要求,可以方便指导非对称悬索桥的方案选择和初步设计.
In order to facilitate the calculation of the natural frequency of symmetrical vertical bending of asymmetrical suspension bridges, Rayleigh method is used to derive the approximate formula of the fundamental frequency of first-order symmetrical vertical bending independently of the consideration of the influence of the cable and the main tower stiffness , The influencing factors of the asymmetric structural parameters and the influencing factors of asymmetric structural parameters included in the sidewalks and the stiffness of the main tower are proposed. The coefficients of influence of the sidewalks and the stiffness of the main tower on the vertical fundamental frequency are given Finally, the accuracy of approximate formula is verified by finite element method.The results show that the stiffness of side cable and main tower can not be ignored when calculating vertical fundamental frequency of asymmetrical suspension bridge. The practical calculation results of the influence are close to those of the finite element method. The error is 3.3%, which can meet the engineering requirements of precision and can guide the scheme selection and preliminary design of the asymmetric suspension bridge.