【摘要】：移動模架施工技術因其施工速度快、機械化程度高、占用場地少及不影響通行和通航,在高墩多跨中等跨徑(30-50m)橋梁現(xiàn)澆施工中已得到廣泛地應用。現(xiàn)階段該法在等寬截面箱梁橋中得到了大量的應用和研究,而對在變寬異性箱梁橋中的應用和研究尚存不足。本文以一多跨的變寬度連續(xù)PC梁橋為依托,運用有限元仿真模擬及正交試驗相結合的手段分析施工及成橋后各參數(shù)對主梁豎向撓度的影響。提出了各設計參數(shù)對橋梁豎向撓度敏感度系數(shù)及其計算式,分析變寬度移動模架施施工過程中及成橋各橋梁線形影響因素關于不同截面的系數(shù)值,旨在確定各因素的重要性和線形關鍵控制點,為采用變寬度移動模架法的PC連續(xù)梁橋施工線形監(jiān)控提供理論依據(jù)和指導,為今后變寬移動模架法施工的同類橋梁提供經(jīng)驗和參考。具體研究內容和相關結論如下:1)在論述剪力柔性梁格法理論的基礎上,對泉州灣跨海大橋秀涂互通主線橋上一五跨一聯(lián)變寬度PC連續(xù)箱梁橋的下行式移動模架施工過程進行仿真分析,驗證了梁格法分析異性寬箱梁結構的可靠性。2)為削弱下行式移動模架施工橋梁懸臂端出現(xiàn)上撓現(xiàn)象,且借用斜拉橋斜拉索索力優(yōu)化的思路,利用未知荷載法確定施工過程中施加在各懸臂端的反頂力值。以施工過程中懸臂端的撓度值±5mm為控制目標,對懸臂端的臨時反向頂推力進行了優(yōu)化設計,尋求合理的頂反力值,使成橋線形更為平順。3)提出各參數(shù)對橋梁豎向撓度敏感系數(shù)計算式,分析下行式移動模架施工過程中及成橋后混凝土容重和彈性模量,鋼束錨下張拉控制應力,預應力管道的摩阻系數(shù)和每米局部偏差對摩擦的影響系數(shù),環(huán)境平均相對濕度,加載齡期,同步升降溫,移動模架剛度等設計參數(shù)對梁體多個節(jié)點的豎向撓度影響的敏感性。分析顯示:五跨一聯(lián)變寬變截面連續(xù)梁橋下行式移動模架施工結構過程中,第三個懸臂段端部撓度對多數(shù)設計參數(shù)均較為敏感,為線形控制最敏感點,而中間兩跨的3L/4和第一懸臂段端部為較敏感點。4)引用多因素水平的正交試驗,對比分析了3種水平7種不同參數(shù)對下行式移動模架施工的PC連續(xù)箱梁橋主梁最敏感點的撓度影響的敏感性,第三懸臂段端點撓度對錨下張拉控制應力、混凝土的容重、混凝土彈性模量較敏感,其中對錨下張拉控制應力最敏感。
[Abstract]:Because of its high construction speed, high mechanization, less occupied space and no influence on traffic and navigation, the construction technology of moving formwork frame has been widely used in the cast-in-place construction of multi-span and medium-span bridges with high piers (30-50m). At present, the method has been widely used and studied in box girder bridges with equal width section, but the application and research of this method in variable-width and heterosexual box-girder bridges are still insufficient. Based on a multi-span continuous PC girder bridge with variable width, the influence of the parameters on the vertical deflection of the main beam is analyzed by means of finite element simulation and orthogonal test. The sensitivity coefficient of the design parameters to the vertical deflection of the bridge and its calculation formula are put forward, and the coefficient values of the factors affecting the different sections of the bridge are analyzed during the construction of the variable width moving mould frame and the influence factors of the bridge alignment. The purpose of this paper is to determine the importance of each factor and the key linear control points, and to provide theoretical basis and guidance for the linear monitoring of PC continuous girder bridge with variable width moving die frame method. It provides experience and reference for similar bridges constructed by widening moving mould frame method in the future. The specific research contents and related conclusions are as follows: 1) on the basis of the theory of shear flexible beam method, This paper simulates and analyzes the construction process of downlink movable mould frame of PC continuous box girder bridge with variable width and one span on the main line bridge of Xiutu interchange of Quanzhou Bay Crossing Sea Bridge. It verifies the reliability of the beam lattice method to analyze the heterosexual wide box girder structure. 2) in order to weaken the upwarping phenomenon at the end of the cantilever of the downlink movable formwork construction bridge, and borrow the train of thought of cable force optimization of the cable-stayed bridge, In this paper, the method of unknown load is used to determine the value of countertop force applied to each cantilever during construction. Taking the deflection value of the cantilever end 鹵5mm as the control target, the temporary reverse thrust of the cantilever end is optimized and the reasonable value of the top reaction force is sought. The formula for calculating the sensitivity coefficient of the parameters to the vertical deflection of the bridge is put forward. The bulk density and elastic modulus of concrete during and after the construction of the downlink movable die frame are analyzed, and the tension control stress under the steel bundle anchor is analyzed. The influence of friction coefficient and local deviation per meter on friction, average relative humidity, loading age, synchronous rising and cooling, stiffness of moving mould frame, and so on, are sensitive to the vertical deflection of beam body. The analysis shows that the end deflection of the third cantilever segment is sensitive to most of the design parameters during the construction of the downlink moving formwork of a continuous beam bridge with variable cross-section and variable cross-section, and is the most sensitive point for linear control. The intermediate two-span 3L/4 and the end of the first cantilever are more sensitive points. 4) the orthogonal test with multi-factor level is used. The sensitivity of three different levels and seven different parameters on the deflection of the main girder of the PC continuous box girder bridge under the downlink moving mold frame is analyzed. The end deflection of the third cantilever section controls the stress under the anchor tension and the bulk density of concrete. The elastic modulus of concrete is more sensitive, among which the tensile stress under anchor is the most sensitive.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U445.463

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