考虑减振装置影响的拱桥吊杆张力测试方法及应用

为了提高振动频率法测试拱桥短吊杆张力的精度,提出联合应用附加质量法和遗传算法的测试方法.通过在吊杆不同高度附加小质量块改变吊杆振动频率获得参数识别条件,利用遗传算法进行极值优化,识别出吊杆张力、弯曲刚度和减振装置横向支承刚度,通过数值模拟和工程实例应用检验了方法的识别精度.结果表明：提出的测试方法能同时识别出张力、弯曲刚度和减振装置横向支承刚度,数值模拟的张力误差不超过1%,工程实例的张力误差不超过7%,为带减振装置的拱桥短吊杆张力测试提供了参考.

Identification method for tensile force in hanger of arch bridges with damper and its application

A method was proposed to improve the measuring precision when using vibration method to measure the short hanger tension.The method identifies the tension,flexural rigidity and damper stiffness simultaneously by combining additional mass method and genetic algorithm.The natural frequency can be changed by adding mass block to different heights of the short hanger.Thus several more identification conditions can be obtained.Not less than four identification conditions should be established in order to identify four parameters,containing hanger tension,flexural rigidity and the damper stiffness at both ends of the hanger.The inverse calculation of the transcendental equations is quite complex.The problem is simplified to a work of minimal optimization.The unknown parameters are identified by the genetic algorithm finally.The identification accuracy was testified by numerical simulation and field measurement.The result evidences that the proposed method can identify the tension,flexural rigidity and damper stiffness simultaneously.The errors of tension are no more than 1% in numerical simulation and 7% in field measurement.The method can be considered as reference in measuring the hanger tension of arch bridges with dampers.