基于多阶频率拟合法监测短粗拉索索力的研究与应用

发布时间：2018-01-14 17:44

本文关键词：基于多阶频率拟合法监测短粗拉索索力的研究与应用　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：索力监测已成为桥梁健康监测的重要内容，准确的索力信息为施工监控、成桥验收、运营管理、科学养护等环节提供直接依据。目前一种高效、经济和便捷的索力测试方法是基于弦模型理论的实测索体振动频率识别索力的方法。但实际应用中，对于直径≥44mm，长度直径比≤100的短粗索，受到边界约束条件，结构整体刚度的影响，此方法难以进行精确的索力监测。针对此不足，本文以渭河大桥单塔无背索斜拉桥索力测试为研究背景，研究基于多阶频率拟合法监测拉索索力的方法。完成的工作内容有：（1）利用数值分析计算，基于索振动理论，考虑不同边界条件和索刚度的影响，对单索振动时频率超越方程进行数值求解，拟合出了不同边界条件下索力关于各阶振动频率的实用计算公式,作为实际应用的参考公式。（2）建立拉索振动模型，针对各种比例短粗索在不同索力下的振动试验，采用快速傅里叶变换与频谱分析获得短索的多阶频率，基于试验结果建立多阶频率优化拟合索力的计算公式。监测计算结果显示其有很高的监测精度和适用性，可以解决短粗索索力监测受边界约束条件及拉索刚度影响等问题。（3）建立拉索动力特性测试系统：基于单塔无背索斜拉桥拉索的特性，结合现场工程实际经验，通过对传感器子系统各项性能参数的研究，提出对传感器、采集设备、激振装置及监测软件等动力测试系统的选择建议。（4）利用多阶频率优化拟合索力监测方法，，对宝鸡市单塔无背索斜拉桥施工过程中索力进行监测，实用公式和多阶频率拟合公式监测索力结果对比显示：①当索力较小时可能出现近10%误差，但通过计算，利用除基频以外的高阶频率计算，仍可以得到较为理想的效果；②索力不很低时，采用拟合的实用公式能够满足工程需要的精度，误差均可以控制在3%以内。所以验证了基于多阶频率优化拟合索力监测方法可行性和准确性，对本项目的安全实施起到指导作用，并对同类型的项目的索力监测起到借鉴作用。
[Abstract]:Cable force monitoring has become an important part of bridge health monitoring, accurate cable force information for bridge construction monitoring, inspection, operation and management, provide a direct basis for scientific maintenance and other aspects. At present, an efficient, economical and convenient cable tension test method is the theory of string model of the measured cable vibration frequency identification of cable force based on the practical application. However, for larger than 44mm in diameter, length diameter ratio less than 100 short cable, by boundary constraints, affect the overall stiffness of the structure, this method is difficult to carry out accurate monitoring of cable force. To solve this problem, this paper takes Weihe bridge of single tower cable stress test on the background of cable-stayed bridge the dorsal funiculus, research methods based on multi frequency fitting monitoring cable force. The working contents are:
(1) analysis by numerical calculation based on the vibration theory of cable, taking into account the influence of different boundary conditions and the stiffness of cable, the single cable vibration frequency beyond the equations are solved numerically fitted calculation formula under different boundary conditions of cable force on the vibration frequency, as a reference formula for practical application.
(2) the establishment of cable vibration model of cable vibration test in different cable force under various proportion of stubby, multi frequency analysis of short cable using the fast Fu Liye transform and spectrum test results to establish the formula of frequency optimization based on cable force monitoring. Results showed that the monitoring accuracy and applicability very high, can solve the problem of short cabletension monitoring affected by boundary conditions and cable stiffness.
(3) the establishment of cable dynamic characteristics testing system: characteristics of cable Backstays based on single tower, combined with the actual experience of on-site engineering, through the research on the performance parameters of the sensor subsystem, the sensor acquisition equipment, recommended to choose the excitation device and monitoring software of the dynamic testing system.
(4) the frequency of monitoring cable force optimization fitting method for Baoji city of single tower cable force monitoring of cable-stayed bridge in the construction process of the dorsal funiculus, results show that the cable force practical formula and multi frequency fitting formula monitoring: when the cable force is relatively small, may be nearly 10% error, but through calculation. The calculation of higher-order frequency except the fundamental frequency by outside, still can get ideal effect; the cable force is not very low, the utility of fitting the formula can satisfy the engineering requirements of the precision, error can be controlled within 3%. So to verify the order frequency optimization fitting based on cable force monitoring method of feasibility and veracity. The project safety implementation plays a guiding role, and the same type of project of cable force monitoring play a role in drawing.

【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U446;U448.27

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