提高斜拉索索力估算精度的一种新方法

根据斜拉桥拉索振动的特点,建立了考虑垂度及斜度影响的振动微分方程,并利用奇异摄动解法进行求解。不仅考虑了索的刚度,而且将索的边界条件假定为简支和固支耦合的情况,在此基础上提出了频率法的索力计算实用公式。分析比较了目前国内外的其他主要计算公式,结果表明该公式具有高精度和计算方便的特点。将该实用计算公式用于南京长江三桥施工控制中,通过对实际斜拉索测试得到的各阶频率进行计算,并与设计索力和压力传感器得到的索力进行对比分析。计算表明该公式能够满足实际工程的需要,可广泛适用于频率法测估各种索类结构的内力。

A New Method to Enhance the Estimation Accuracy of Stay Cable Tension

According to vibration characteristic of cable in cable-stayed bridges,the non-linear dynamic model of stay cable is set up with consideration of deflection and inclination,and the vibration differential equation is deduced using the singular perturbation method.The stiffness and coupling boundary conditions of simple and fixed bearing are introduced in the cable tension analysis.The useful formula of cable tension calculation with frequency method is advanced.Results of analyses indicate that the formula is high in accuracy and convenient in practice.The formula is used to the cable-stayed construction control of Nanjing Yangtze River No.3 Bridge.The cable tension is calculated with test data of stay cable,and are compared with cable tension of design and tension sensor.The method can be widely used for field of measurement during the construction of cable system structures.