基于频率法的悬索桥锚跨索股索力测试分析

Cable Force Test and Analysis of Anchor Span Stand for Suspension Bridges Based on Frequency Method

为准确获得悬索桥锚跨索股索力,便于在施工过程中对索力进行精确控制,针对锚跨结构的构造特点,采用振动频率法进行锚跨索股索力测试,分析激励方式、传感器的布置位置等因素对振动频率识别的影响,得到索股在不同应力、频率阶次、拉索长度下索力计算结果的变化规律。研究结果表明:采用频率法进行测量时,应尽量选用人工激励;传感器布置位置受到限制时,可将传感器布置到距离索股端部L/6处,以便更加准确识别拉索振动频率;进行索股索力计算时,选取1阶固有频率能较好保证索力计算的精度要求;索股的应力接近其正常受拉承载能力极限状态时,拉索的材料属性得到充分发挥,索力计算误差较小。

In order to obtain cable force of anchor span stand for suspension bridges precisely so that the cable force can be controlled easily and accurately during construction,the cable force is tested by frequency method based on the construction characteristics of anchor span structure.Factors affecting frequency identification such as incentive mode,sensor placement and so on are analyzed.The variation law of the cable force for cable stand with different stress,frequency order and cable length is obtained.The results show that when using the frequency method for measurement,the artificial incentive should be a prior selection to the others.In order to identify the cable vibration frequency accurately,the sensor can be arranged at L/6distance away from the cable end.The accuracy of the cable force calculation can be ensured by selecting the first-order natural frequency in the calculation.When the stress of the cable stand is close to its tensile limit,the material properties of the cable are fully utilized and the calculation error is small.