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大跨度预应力结构健康监测中在役预应力索力的测试识别精度关系到整个结构的安全,测试在役钢索索力有频率法、磁通量法等多种方法且各有特点,频率法的基频不易识别,磁通量法标量不准且操作繁杂。据此采用基于正弦激振的多频率拟合方法测试在役索力,建立多跨索振动模型和索力优化识别模型,以索力测量试验和某张弦梁结构的展览馆为实例,采用正弦多频率拟合法拾取多阶频率并进行优化分析。结果表明,对拉索施加正弦激振获得的多阶频率进行拟合优化计算比一般计算公式法计算的索力更接近实测索力,并且拉索的长径比在100以内的索力测量中,多频率拟合法的优势更明显,为基于正弦激振的多频率拟合法提供了依据。
Large span prestressed structure health monitoring in-service prestressed cable test identification accuracy is related to the safety of the entire structure, test the existing cable force with frequency method, magnetic flux method and many other methods have their own characteristics, the frequency method of the base Frequency is not easy to identify, magnetic flux scalar is not allowed and complicated operation. Based on this, a multi-frequency fitting method based on sinusoidal excitation is used to test the cable force in service, and the multi-cable vibration model and the cable force optimization identification model are established. Taking the cable force test and a string structure as an example, Frequency fitting method to pick up multi-order frequency and optimize the analysis. The results show that the fitting and optimization calculation of multi-order frequencies obtained by applying sinusoidal excitation to the cable is closer to the measured cable force than the cable force calculated by the general formula and the cable length-diameter ratio is less than 100 , The advantage of multi-frequency fitting is more obvious, which provides a basis for multi-frequency fitting based on sinusoidal excitation.