基于两端固支的短吊杆频率计算研究

Research on Frequency Calculation of Short Suspension Rod with Fixed Support at Both Ends

为了分析抗弯刚度对短吊杆频率的影响,解决短吊杆索力自振频率计算精度较低的问题,基于现有两端固支考虑斜拉索非线性振动的自振频率计算公式,以某实际工程中64 m下承式系杆拱桥为实验分析对象,通过实际张拉测出的实测数据并结合有限元软件建立考虑吊杆抗弯刚度的模型,分析抗弯刚度对不同长度吊杆索力的影响;引入理论自振频率修正公式的方法,拟合出理论频率的修正公式,应用到83 m下承式系杆拱桥施工监控中。算例表明,相较于传统的频率计算公式,使用该方法吊杆张拉误差更小,且对短吊杆的误差均在±5%以内。

In order to analyze the influence of flexural stiffness on the frequency of short suspension rod and solve the problem of low calculation accuracy of natural vibration frequency of short suspension rod tension,based on the existing formula of natural vibration frequency considering the non-linear vibration of the cable-stayed cables with fixed support at both ends,the experimental analysis with a 64 m through tied arch bridge in a practical project as the object was established.By using the measured data of actual tension and finite element software,a model considering the flexural stiffness of suspension rod was established to analyze the influence of flexural stiffness on the cable force of suspension rods of different lengths.The method of the correction formula of the theoretical natural vibration frequency was introduced and the correction formula of the theoretical frequency was fitted out.The application of this method to the construction monitoring of 83 m tied arch bridge shows that compared with the traditional frequency calculation formula,the tension error of the suspension rod is smaller and the error of the short suspension rod is within plus or minus 5%.