本文關(guān)鍵詞： 鐵路預(yù)應(yīng)力混凝土梁 有效預(yù)應(yīng)力 有限元模擬 自振頻率 動力試驗(yàn)　出處：《石家莊鐵道大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：京通線48號橋位于懷柔北到小水峪間，中心里程K60+481，為單線橋，1974年建成，橋上直線平坡，孔跨式樣為16孔跨度23.8m預(yù)應(yīng)力混凝土T梁，主梁中心距1.8m，梁高2.1m，跨中腹板厚0.14m，搖軸支座，圓端形混凝土墩，橋高10m左右，該梁采用直徑為5mm的碳素鋼絲構(gòu)成五種預(yù)應(yīng)力鋼筋N1、N2、N3、N4、N5，共9束沿梁長曲線布置。本文以其中一跨為研究對象，通過理論計(jì)算、有限元通用軟件ANSYS進(jìn)行模擬加上現(xiàn)場實(shí)體試驗(yàn)三種途徑對該梁現(xiàn)存的有效預(yù)應(yīng)力進(jìn)行計(jì)算識別并利用軟件模型探討預(yù)應(yīng)力對梁自振頻率的影響及其之間的關(guān)系。主要完成以下工作： (1)用有限元軟件ANSYS建立試驗(yàn)梁的模型，進(jìn)行梁的前五階頻率計(jì)算，在此基礎(chǔ)上，將預(yù)應(yīng)力鋼筋束整體和分組結(jié)合組成多種計(jì)算情況分別計(jì)算了梁體在不同預(yù)應(yīng)力值的組合下的自振頻率值，模擬計(jì)算結(jié)果表明，自振頻率隨著預(yù)應(yīng)力的減小而減小，在全預(yù)應(yīng)力、部分預(yù)應(yīng)力和無預(yù)應(yīng)力三種狀態(tài)的界限處的改變值很明顯，，而且，預(yù)應(yīng)力筋所處的位置和所施加的預(yù)應(yīng)力值的大小都會對自振頻率有不同的影響。 (2)對原橋進(jìn)行動載試驗(yàn)測得在有效預(yù)應(yīng)力水平下的自振頻率，在實(shí)體試驗(yàn)梁上進(jìn)行消壓荷載試驗(yàn)和開槽法試驗(yàn)對有效預(yù)應(yīng)力值進(jìn)行檢測，將動載試驗(yàn)得到的頻率值代入模型計(jì)算得到的有效預(yù)應(yīng)力和頻率關(guān)系曲線中得到有效預(yù)應(yīng)力值，驗(yàn)證頻率和有效預(yù)應(yīng)力之間的關(guān)系以及利用頻率識別有效預(yù)應(yīng)力值的可行性。 (3)了解試驗(yàn)梁的基本情況，參照中國、美國、歐洲三種預(yù)應(yīng)力損失的計(jì)算方法和公式，按照我國規(guī)定對試驗(yàn)梁的有效預(yù)應(yīng)力值和頻率進(jìn)行理論計(jì)算。 (4)結(jié)合理論、模擬和實(shí)體試驗(yàn)得到的梁體有效預(yù)應(yīng)力值和梁的動力特性值，對本文的有效預(yù)應(yīng)力識別方法進(jìn)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.
【學(xué)位授予單位】：石家莊鐵道大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U441.5

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