超大跨徑UHPC連續(xù)梁橋優(yōu)化設(shè)計研究
發(fā)布時間：2018-10-19 07:19
【摘要】：將超高性能混凝土（Ultra-high Performance Concrete，UHPC）運(yùn)用于梁橋，充分利用其超高的材料強(qiáng)度、優(yōu)良的耐久性及超低的收縮徐變性能，設(shè)計新型的橋梁結(jié)構(gòu)形式，從而實現(xiàn)結(jié)構(gòu)輕型化，解決常規(guī)混凝土梁橋自重過大、跨中長期下?lián)习l(fā)展、箱梁易開裂、跨徑難以突破300m的難題。該新型結(jié)構(gòu)突出特點是箱梁全面的薄壁化，同時提出密集橫隔板的設(shè)計思想，解決由薄壁化引起的畸變和剪力滯效應(yīng)過大問題，還能改善箱梁橫向受力，變?nèi)蝾A(yù)應(yīng)力為單向預(yù)應(yīng)力，方便施工。擬定主跨400m的連續(xù)梁橋為工程背景，通過優(yōu)化設(shè)計，研究該橋邊跨比、梁高、板厚及密集橫隔板等各參數(shù)的合理取值。本文開展的主要研究及其結(jié)論如下： （1）利用MIDAS軟件建立主跨400m連續(xù)薄壁箱梁橋空間梁單元模型，對箱梁橋的整體參數(shù)（邊跨比、梁高、板件厚度、預(yù)應(yīng)力筋）進(jìn)行優(yōu)化。根據(jù)各參數(shù)對橋梁整體性能影響的大小順序以及各參數(shù)自身的特點選擇合適的目標(biāo)函數(shù)和約束條件分別進(jìn)行優(yōu)化分析，后者的優(yōu)化分析以前面的分析結(jié)果為基礎(chǔ)。經(jīng)一系列優(yōu)化分析可得：①最優(yōu)邊跨—主跨跨徑比為0.6，合理的取值范圍為0.55~0.65；②最優(yōu)中支點梁高與主跨跨徑比1/22.2，合理的取值范圍為1/20~1/25；③最優(yōu)跨中梁高與支點梁高比為1/1.8077，合理的取值范圍為1/1.8~1/2.3；④最優(yōu)中支點底板厚度與主跨跨徑比1/500，合理的取值范圍為1/300~1/500；⑤合理的頂板、跨中底板厚度和跨中腹板厚度取其構(gòu)造最小厚度20cm，合理支點腹板厚度可取35cm。 （2）通過對新型箱梁橋的初步徐變分析，建議在設(shè)計時UHPC梁橋的長期撓度增長系數(shù)取1.3，同時研究表明支點底板厚度對徐變下?lián)嫌休^大影響，建議在確定其厚度時考慮徐變下?lián)系囊蛩兀�，不宜取得過小。 （3）利用有限元分析軟件ANSYS建立半橋?qū)嶓w模型，分兩步對密集橫隔板進(jìn)行優(yōu)化：密集橫隔板間距和橫隔板上、下弦板高度和側(cè)板寬度。全面分析橫隔板間距對箱梁畸變、剪力滯和橋面板局部受力方面的影響以得到較優(yōu)的間距范圍。橫隔板上、下弦板高度和側(cè)板寬度優(yōu)化則從合理的尺寸分布對減小橋梁局部受力的貢獻(xiàn)分析。經(jīng)優(yōu)化分析得到較優(yōu)的橫隔板間距范圍為3~5m；分配密集橫隔板尺寸時宜適當(dāng)增加密集橫隔板上弦板高度和橫隔板厚度，以改善箱梁橋的局部受力狀態(tài)。
[Abstract]:The ultra-high performance concrete (Ultra-high Performance Concrete,UHPC) is applied to the beam bridge to make full use of its super high material strength, excellent durability and ultra low shrinkage and creep property, and design a new type of bridge structure form, thus realizing the light weight of the structure. To solve the problem that the weight of conventional concrete beam bridge is too large, the span is long term deflection development, the box girder is easy to crack and the span is difficult to break through 300m. The outstanding feature of the new structure is the overall thin-wall of the box girder. At the same time, the design idea of the dense transverse diaphragm is put forward to solve the problem of excessive distortion and shear lag caused by the thin-walled structure, and the transverse force of the box girder can also be improved. Changing three-way prestress to one-way prestressing is convenient for construction. The continuous beam bridge with 400m main span is selected as the engineering background. Through the optimization design, the reasonable selection of the bridge side span ratio, beam height, plate thickness and dense transverse partition are studied. The main research and conclusions in this paper are as follows: (1) the spatial beam element model of 400m continuous thin-walled box girder bridge with main span is established by using MIDAS software. The integral parameters of box girder bridge (side span ratio, beam height, plate thickness) are analyzed. Prestressing tendons) are optimized. According to the order of the influence of each parameter on the overall performance of the bridge and the characteristics of each parameter, the appropriate objective function and constraint conditions are selected for optimization analysis respectively. The optimization analysis of the latter is based on the results of the previous analysis. Through a series of optimization analysis, the following conclusions can be obtained: (1) the optimum ratio of side span to main span is 0.6, the reasonable value range is 0.55 ~ 0.65 ~ 2, the optimum ratio of height to span of middle fulcrum beam is 1 / 22. 2, and the reasonable value range is 1 / 20 / 1 / 25; (3) the optimum ratio of midspan height to fulcrum beam height is 1 / 1.8077, and the reasonable value range is 1 / 1. 8 / 1 / 2. 3 / 3. 4 the optimal ratio of bottom thickness to main span is 1 / 500, and the reasonable value range is 1 / 300 / 1 / 5005. The thickness of the bottom plate of span and the thickness of web plate of span center are taken as the minimum thickness of the structure 20 cm, and the thickness of the web plate of the reasonable fulcrum can be 35 cm. (2) the preliminary creep analysis of the new type box girder bridge is carried out. It is suggested that the long-term deflection growth coefficient of UHPC girder bridge should be 1.3.The study shows that the thickness of fulcrum bottom plate has great influence on creep deflection, and it is suggested that the factors of creep deflection should be taken into account when determining the thickness of UHPC girder bridge. (3) using the finite element analysis software ANSYS to establish the solid model of half-bridge, and optimize the dense transverse diaphragm in two steps: the spacing of the dense transverse diaphragm, the height of the lower chord plate and the width of the lateral plate. The influence of the distance between the transverse partitions on the box girder distortion, shear lag and local force on the bridge deck is analyzed in order to obtain a better range of spacing. The optimization of the height of the lower chord plate and the width of the lateral plate on the transverse diaphragm is analyzed from the contribution of the reasonable size distribution to the reduction of the local force of the bridge. Through the optimization analysis, the optimum spacing range of the transverse diaphragm is 3 ~ 5 m, and the appropriate increase of the height and thickness of the upper chord plate and the thickness of the transverse partition plate should be appropriately increased to improve the local stress state of the box girder bridge.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U448.215
本文編號：2280514
[Abstract]:The ultra-high performance concrete (Ultra-high Performance Concrete,UHPC) is applied to the beam bridge to make full use of its super high material strength, excellent durability and ultra low shrinkage and creep property, and design a new type of bridge structure form, thus realizing the light weight of the structure. To solve the problem that the weight of conventional concrete beam bridge is too large, the span is long term deflection development, the box girder is easy to crack and the span is difficult to break through 300m. The outstanding feature of the new structure is the overall thin-wall of the box girder. At the same time, the design idea of the dense transverse diaphragm is put forward to solve the problem of excessive distortion and shear lag caused by the thin-walled structure, and the transverse force of the box girder can also be improved. Changing three-way prestress to one-way prestressing is convenient for construction. The continuous beam bridge with 400m main span is selected as the engineering background. Through the optimization design, the reasonable selection of the bridge side span ratio, beam height, plate thickness and dense transverse partition are studied. The main research and conclusions in this paper are as follows: (1) the spatial beam element model of 400m continuous thin-walled box girder bridge with main span is established by using MIDAS software. The integral parameters of box girder bridge (side span ratio, beam height, plate thickness) are analyzed. Prestressing tendons) are optimized. According to the order of the influence of each parameter on the overall performance of the bridge and the characteristics of each parameter, the appropriate objective function and constraint conditions are selected for optimization analysis respectively. The optimization analysis of the latter is based on the results of the previous analysis. Through a series of optimization analysis, the following conclusions can be obtained: (1) the optimum ratio of side span to main span is 0.6, the reasonable value range is 0.55 ~ 0.65 ~ 2, the optimum ratio of height to span of middle fulcrum beam is 1 / 22. 2, and the reasonable value range is 1 / 20 / 1 / 25; (3) the optimum ratio of midspan height to fulcrum beam height is 1 / 1.8077, and the reasonable value range is 1 / 1. 8 / 1 / 2. 3 / 3. 4 the optimal ratio of bottom thickness to main span is 1 / 500, and the reasonable value range is 1 / 300 / 1 / 5005. The thickness of the bottom plate of span and the thickness of web plate of span center are taken as the minimum thickness of the structure 20 cm, and the thickness of the web plate of the reasonable fulcrum can be 35 cm. (2) the preliminary creep analysis of the new type box girder bridge is carried out. It is suggested that the long-term deflection growth coefficient of UHPC girder bridge should be 1.3.The study shows that the thickness of fulcrum bottom plate has great influence on creep deflection, and it is suggested that the factors of creep deflection should be taken into account when determining the thickness of UHPC girder bridge. (3) using the finite element analysis software ANSYS to establish the solid model of half-bridge, and optimize the dense transverse diaphragm in two steps: the spacing of the dense transverse diaphragm, the height of the lower chord plate and the width of the lateral plate. The influence of the distance between the transverse partitions on the box girder distortion, shear lag and local force on the bridge deck is analyzed in order to obtain a better range of spacing. The optimization of the height of the lower chord plate and the width of the lateral plate on the transverse diaphragm is analyzed from the contribution of the reasonable size distribution to the reduction of the local force of the bridge. Through the optimization analysis, the optimum spacing range of the transverse diaphragm is 3 ~ 5 m, and the appropriate increase of the height and thickness of the upper chord plate and the thickness of the transverse partition plate should be appropriately increased to improve the local stress state of the box girder bridge.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U448.215
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