铁路预应力混凝土T梁预应力损失识别方法研究

发布时间：2018-02-11 23:53

本文关键词： 铁路预应力混凝土梁有效预应力有限元模拟自振频率动力试验　出处：《石家庄铁道大学》2014年硕士论文　论文类型：学位论文

【摘要】：京通线48号桥位于怀柔北到小水峪间，中心里程K60+481，为单线桥，1974年建成，桥上直线平坡，孔跨式样为16孔跨度23.8m预应力混凝土T梁，主梁中心距1.8m，梁高2.1m，跨中腹板厚0.14m，摇轴支座，圆端形混凝土墩，桥高10m左右，该梁采用直径为5mm的碳素钢丝构成五种预应力钢筋N1、N2、N3、N4、N5，共9束沿梁长曲线布置。本文以其中一跨为研究对象，通过理论计算、有限元通用软件ANSYS进行模拟加上现场实体试验三种途径对该梁现存的有效预应力进行计算识别并利用软件模型探讨预应力对梁自振频率的影响及其之间的关系。主要完成以下工作： (1)用有限元软件ANSYS建立试验梁的模型，进行梁的前五阶频率计算，在此基础上，将预应力钢筋束整体和分组结合组成多种计算情况分别计算了梁体在不同预应力值的组合下的自振频率值，模拟计算结果表明，自振频率随着预应力的减小而减小，在全预应力、部分预应力和无预应力三种状态的界限处的改变值很明显，，而且，预应力筋所处的位置和所施加的预应力值的大小都会对自振频率有不同的影响。 (2)对原桥进行动载试验测得在有效预应力水平下的自振频率，在实体试验梁上进行消压荷载试验和开槽法试验对有效预应力值进行检测，将动载试验得到的频率值代入模型计算得到的有效预应力和频率关系曲线中得到有效预应力值，验证频率和有效预应力之间的关系以及利用频率识别有效预应力值的可行性。 (3)了解试验梁的基本情况，参照中国、美国、欧洲三种预应力损失的计算方法和公式，按照我国规定对试验梁的有效预应力值和频率进行理论计算。 (4)结合理论、模拟和实体试验得到的梁体有效预应力值和梁的动力特性值，对本文的有效预应力识别方法进行研究。
[Abstract]:Jingtong Line 48 Bridge is located between Huairou North and Xiaoshuiyu. The center mileage is K60481. it is a single-line bridge. In 1974, the bridge has a straight flat slope with a 16-hole span of 23.8m prestressed concrete T-beam. The center distance of the main beam is 1.8 m, the beam height is 2.1 m, the thickness of the span is 0.14 m, the rocking shaft supports, the round end concrete pier, the bridge height is about 10 m, The beam is composed of five kinds of prestressed steel bar N _ (1) N _ (2) N _ (2) N _ (3) N _ (3) N _ (4) N _ (5) with a diameter of 5 mm. A total of 9 beams are arranged along the beam length curve. In this paper, one span is taken as the research object, and the theoretical calculation is carried out. The finite element general software ANSYS is used to simulate and test the existing effective prestressing force of the beam. The influence of prestress on the natural vibration frequency of beam and the relationship between them are discussed by using the software model. The main tasks are as follows:. 1) using the finite element software ANSYS to establish the model of the test beam, and calculate the first five order frequency of the beam, on the basis of which, The self-vibration frequency of beam under different prestress values is calculated separately by combining the whole and grouping of prestressed bars. The simulation results show that the natural vibration frequency decreases with the decrease of prestress. The change value at the boundary of full prestress, partial prestress and non prestressing is obvious. Moreover, the position of prestressing tendons and the magnitude of prestressing force applied will have different effects on the natural vibration frequency. (2) the natural vibration frequency of the original bridge is measured by dynamic load test under the effective prestressing force level, and the effective prestress value is tested by the static load test on the solid test beam and the slotted test. The frequency value obtained from dynamic load test is substituted into the effective prestressing force and the effective prestress value is obtained in the curve of frequency relation, which verifies the relationship between frequency and effective prestress and the feasibility of identifying the effective prestress value by frequency. (3) to understand the basic situation of the test beam, according to the calculation methods and formulas of three kinds of prestress loss in China, the United States and Europe, the effective prestress value and frequency of the test beam are calculated theoretically according to the regulations of our country. 4) combined with the theory, the effective prestress value of beam and the dynamic characteristic value of beam obtained by simulation and solid test, the identification method of effective prestressing force in this paper is studied.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.5

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