灌浆拉索振动理论与索力研究

发布时间：2018-02-25 20:32

本文关键词： 灌浆拉索弹性附加质量轴拉梁模型试验索力研究　出处：《福州大学》2014年硕士论文　论文类型：学位论文

【摘要】：上世纪70-90年代,我国交通基本建设迅速发展,期间建设了大量的中、下承式吊杆拱桥和斜拉桥。当时多数吊杆和斜拉索的防腐构造是外套套管并内灌水泥浆,由于套管和水泥浆的存在,采用现有的振动法理论来测试和计算拉索索力会产生较大的误差。随着体外预应力技术的日益进步,灌浆体外预应力索在新建桥梁及已有桥梁结构的体外预应力加固中得到了更广泛的运用,这也对采用振动频率法测试此类拉索的索力提出了新的要求和挑战。为能运用振动频率法较为准确地测试灌浆拉索索力,本文进行了深入的理论研究和大量的灌浆拉索模型试验。主要工作和结论如下：(1)在介绍了根据弦振动理论和轴拉梁振动理论求解拉索索力的最基本公式的基础上,简要推导了铰接和固结两种不同边界条件下拉索在一般均布质量作用下的索力计算公式和在集中附加质量作用下的振动频率方程。(2)以洪塘大桥体外预应力索和拱桥灌浆吊杆为工程背景,采用Φ15.2mm高强度钢绞线模拟拉索,制作了24个裸索试验模型、24个外套PVC套管(未灌浆)拉索试验模型以及24个灌浆拉索试验模型,分别研究了边界条件、套管附加质量以及灌浆拉索的各参数对索力计算的影响规律。结果表明：铰接的边界条件满足试验中索力计算的要求,计算外套套管的拉索索力时需计入附加质量的影响,但采用现有索力计算公式计算灌浆拉索索力会产生很大的误差。(3)将灌浆拉索视为带有均布附加弹性质量的两端铰接轴向受拉梁,根据弹性分布质量与拉索振动方向的两种不同情况分别建立拉索的振动微分方程。对试验数据拟合分析,得到了采用索长、灌浆率、附加质量线密度、长细比、砂浆抗弯刚度等参数求解附加弹性质量自振频率的计算表达式,并结合附加质量、裸索、灌浆拉索实测和计算频率之间的关系,提出了灌浆拉索索力计算方法。结果表明：计算得到的拉索索力最大误差为5.39%,具有很高的计算精度。(4)进行了洪塘大桥灌浆体外索的1：1原型试验,验证了本文提出的灌浆拉索计算方法的适用性,将公式运用于福建省洪塘大桥灌浆体外索和仙游木兰溪大桥吊杆的索力评定中,计算精度满足工程要求。
[Abstract]:In 0th century, the transportation infrastructure developed rapidly in China, during which a large number of through arch bridges and cable-stayed bridges were built. At that time, the anticorrosion structure of most suspenders and stayed cables was jacket casing and internal irrigation mud. Due to the existence of casing and cement slurry, there will be great errors in the measurement and calculation of cable tension by using the existing vibration theory. With the progress of external prestressing technology, Grouting external prestressed cables have been widely used in the reinforcement of new bridges and existing bridge structures. It also puts forward new requirements and challenges for using vibration frequency method to test the cable force of this kind of cable, in order to be able to use vibration frequency method to test the cable force of grouting cable more accurately. In this paper, a deep theoretical study and a large number of grouting cable model tests have been carried out. The main work and conclusions are as follows: 1) on the basis of introducing the most basic formulas for solving the cable force according to the theory of string vibration and the theory of vibration of the axle-stayed beam, In this paper, the formulas for calculating cable force under the action of general uniform mass and vibration frequency equation under the action of concentrated additional mass for two different boundary conditions of hinged and consolidated cables are derived.) the external prestressing cables and arches of Hongtang Bridge are used in this paper. The bridge grouting suspender is the background of the project. Using 桅 15.2mm high strength steel strand to simulate the cable, 24 bare cable test models, 24 PVC casing (ungrouted) cable test models and 24 grouting cable test models were made, and the boundary conditions were studied respectively. The influence of the additional mass of casing and the parameters of grouting cable on the calculation of cable force is studied. The results show that the boundary condition of hinge meets the requirement of cable force calculation in test, and the influence of additional mass should be taken into account in calculating cable force of casing casing. However, using the existing formula to calculate the tension of the grouting cable will result in a great error. (3) the grouting cable is regarded as a hinged axial tension beam with uniformly distributed additional elastic mass at both ends. According to the two different conditions of elastic distribution mass and cable vibration direction, the vibration differential equation of cable is established, and the cable length, grouting rate, additional mass linear density and aspect ratio are obtained by fitting and analyzing the test data. The calculation expression of the natural vibration frequency of the additional elastic mass is solved by the parameters of mortar bending stiffness, and the relationship between the measured and calculated frequency of the additional mass, bare cable, grouting cable, etc. A method for calculating the cable force of grouting cable is put forward. The results show that the maximum error of cable force calculated is 5.39 and has a high precision of calculation. The 1: 1 prototype test of grouting external cable of Hongtang Bridge is carried out. The applicability of the method proposed in this paper is verified, and the formula is applied to evaluate the cable force of the grouting external cables of Hongtang Bridge and the suspender of Mulan Xi Bridge in Xianyou. The calculation accuracy meets the requirements of engineering.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.27

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