【摘要】：大跨徑預應力混凝土箱梁橋腹板設置豎向預應力筋的主要目的在于抵抗腹板的主拉應力和剪力,從而達到防止箱梁腹板開裂的目的。但是,箱梁橋腹板斜裂縫病害卻始終存在。一方面是由于豎向預應力張拉過程中操作不當、預應力筋定位誤差大以及預應力筋回縮等原因造成的錨固后實際張拉力不足；另一方面是由于豎向預應力管道壓漿不密實造成豎向預應力筋銹蝕產生預應力損失導致的實際張拉力不足。因此,如何提高豎向預應力筋的張拉質量及減小運營期長期損失以提供足夠的張拉力,成為研究重點。本文針對豎向預應力筋張拉力及管道壓漿密實度進行了數(shù)值分析及模型試驗研究,主要研究工作如下：1)本文詳細闡述了選題背景、目的意義。介紹了國內外學者對豎向預應力張拉力和管道壓漿密實度無損檢測方法的研究現(xiàn)狀。2)根據(jù)結構動力學理論分別通過公式推導與有限元數(shù)值模擬的方法對豎向預應力鋼筋外露段的頻率特性進行了對比分析。3)通過模型試驗獲得φ32精軋螺紋鋼筋實際張拉力與錨固段剛度增大系數(shù)之間的經驗公式,并將研究成果應用于實橋,有效提高了豎向預應力張拉質量。4)簡要介紹彈性波及沖擊回波法基本原理,對沖擊回波時域信號轉換為頻域信號的傅里葉變換進行簡單說明。同時,根據(jù)彈性波縱波傳播理論詳細分析了縱波在五種壓漿密實程度下的傳播路徑。5)進行了現(xiàn)場模型試驗,模擬了不同厚度下全空、1/4密實、1/2密實、3/4密實、完全密實五種壓漿工況,并測試其沖擊回波主頻。試驗結果與有限元數(shù)值分析結果一致,即沖擊回波主頻與管道壓漿密實度均呈現(xiàn)顯著的線性關系。6)根據(jù)有限元數(shù)值分析結果得到了沖擊回波主頻與管道壓漿密實度在一定參數(shù)下的經驗公式,并利用該經驗公式進行了豎向預應力孔道壓漿密實性的定量評估。
[Abstract]:The main purpose of installing vertical prestressed tendons on the web plate of long-span prestressed concrete box girder bridge is to resist the main tensile stress and shear force of the web so as to prevent the box girder web from cracking. However, the box girder bridge web slant crack disease has always existed. On the one hand, the actual tension after anchoring is insufficient due to improper operation in the process of vertical prestressing tensioning, large positioning error of prestressed tendons and retraction of prestressed tendons. On the other hand, the actual tensile force is insufficient due to the corrosion of the vertical prestressed tendons caused by the uncompacted grouting of the vertical prestressed pipes. Therefore, how to improve the tensioning quality of vertical prestressed tendons and reduce the long-term losses in operation to provide enough tension has become the focus of research. In this paper, the tensile force of vertical prestressed tendons and the density of pipe grouting are studied by numerical analysis and model test. The main research work is as follows: 1) the background and purpose significance of this paper are described in detail. This paper introduces the research status of nondestructive testing methods for vertical prestressing tension and grouting compactness of pipeline at home and abroad. 2) according to the theory of structural dynamics, the vertical tension is derived by formula derivation and finite element numerical simulation, respectively. The frequency characteristics of the exposed segment of prestressed steel bar are compared and analyzed. 3) the empirical formula between the actual tensile force of 蠁 32 finish rolled rebar and the increasing coefficient of stiffness of anchoring section is obtained by model test. The research results are applied to the real bridge, which effectively improves the quality of vertical prestressing tension. 4) the basic principle of elastic wave and impact echo method is briefly introduced, and the Fourier transform from the time domain signal of impact echo to the frequency domain signal is simply explained. At the same time, according to the theory of elastic wave P-wave propagation, the propagation paths of P-wave under five kinds of slurry compactness are analyzed in detail. 5) the field model test is carried out, and the whole space, 1 / 4 density, 1 / 2 density under different thickness are simulated. 3 / 4 compactness, complete compactness, five grouting conditions, and test the main frequency of shock echo. The experimental results are consistent with the results of finite element numerical analysis. That is, the linear relationship between the main frequency of shock echo and the grouting density of pipeline is obvious. 6) based on the results of finite element numerical analysis, the empirical formula of the main frequency of shock echo and the degree of slurry compactness of pipeline under certain parameters is obtained. The empirical formula is used to quantitatively evaluate the compactness of vertical prestressing channels.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U445.57

【參考文獻】

相關期刊論文 前1條

1 李海軍,李軍;連續(xù)梁橋預應力箱梁腹板裂縫成因淺析[J];華東公路;2000年03期

，

本文編號：2377067