基于频率法的短吊杆索力测试

Determing short suspender tension based on frequency method

为提高基于频率法的短吊杆索力测试精度,结合现有文献中吊杆索力与其自振频率之间的显式关系式,通过对影响吊杆索力测试精度的因素进行分析,引入边界条件修正系数λ修正吊杆两端复杂边界条件;在频率法测试吊杆拉力计算公式的基础上,引入吊杆索力偏差系数η用于短吊杆的界定;提出一种考虑短吊杆抗弯刚度、复杂边界条件的索力比例系数标定方法及索力计算公式。将其运用在某64 m下承式钢管混凝土系杆拱桥施工监控中,算例表明:相对于传统索力测试计算方法,使用该方法使短吊杆索力测试精度提高了13.4%,且吊杆有效长度越短,精度提高得越多。

To improve the accuracy of the short suspender tension determined based on the frequency method,in combination with the relationship between suspender tension and its natural vibration frequency in the existing literature and through comprehensive analysis of the factors affecting the monitoring accuracy of the cable force of the boom,the boundary condition correction coefficient“λ”was introduced to correct the boundary conditions at both ends of the suspender.Based on the commonly used formula for calculating the tension of the suspender based on the frequency method,the stiffness parameter“η”of the suspender was used to define the short suspender.A method for calibrating the suspender tension proportional coefficient considering the bending stiffness and boundary conditions of short boom and the suspender tension calculation formula were proposed.It was used for monitoring and controlling suspender tension of a 64 m through CFST tied arch bridge,which shows that compared with the traditional suspender tension calculation method,the use of this method improves the accuracy of the short suspender tension by 13.4%,and that the shorter the effective length of the boom,the greater improvement of the accuracy.