混凝土矩形空心墩溫度作用及豎向開裂問題研究
發(fā)布時間：2018-08-29 15:33
【摘要】：我國現(xiàn)行公路橋梁設(shè)計規(guī)范對于混凝土橋梁均勻溫度作用的規(guī)定較為粗略,與全國范圍內(nèi)差異甚大的氣候條件之間存在一定矛盾;目前國內(nèi)針對混凝土矩形空心墩非均勻溫度作用的系統(tǒng)性研究成果也相對較少,不便于設(shè)計分析人員參考使用;另外不少混凝土矩形空心墩出現(xiàn)了豎向開裂病害,目前系統(tǒng)性的成因分析和裂縫控制研究還較為缺乏。本文通過試驗研究與數(shù)值模擬相結(jié)合的方法,對混凝土矩形空心墩的溫度作用取值、溫度效應(yīng)計算的關(guān)鍵參數(shù)以及豎向開裂的機理和防治措施進行了深入研究,主要研究工作和結(jié)論如下:基于溫度長期觀測資料,系統(tǒng)研究了混凝土空心墩平均溫度與外氣溫的關(guān)系,提出了兩種根據(jù)氣溫資料預(yù)測空心墩平均溫度變化范圍的方法,通過對試驗橋墩在觀測期內(nèi)平均溫度變化范圍的預(yù)測,發(fā)現(xiàn)在最高、最低日平均氣溫的基礎(chǔ)上增加2oC時得到的溫度變化范圍與預(yù)測范圍基本吻合;參照歐洲結(jié)構(gòu)設(shè)計標準,建議取50年重現(xiàn)期的最高、最低日平均氣溫作為基本氣溫,在基本氣溫的基礎(chǔ)上增加2oC得到混凝土橋梁有效溫度的標準值,通過統(tǒng)計分析,得到了全國194個氣象站混凝土橋梁有效溫度的推薦值,并與現(xiàn)行公路橋梁設(shè)計規(guī)范進行了對比分析,指出了其不足之處,并提出了有關(guān)混凝土橋梁均勻溫度作用的建議�；跍囟乳L期觀測資料,系統(tǒng)研究了混凝土空心墩正溫差、負溫差作用與氣象條件的關(guān)系;通過對混凝土矩形空心墩日照溫度場和寒潮降溫溫度場的實測和有限元模擬,提出了混凝土矩形空心墩非均勻溫度作用的二維溫差分布模式和沿壁厚方向的冪函數(shù)溫差分布曲線;搜集了全國20個代表性地點的大氣透明系數(shù)、氣溫日較差、日平均氣溫24小時最大降溫幅度、日平均風速等資料,采用有限元模擬方法,得到了20個代表性測站的最大壁面正溫差和負溫差標準值,并通過擬合計算和綜合分析,給出了冪函數(shù)常量a和溫度變化影響深度b的建議值。對混凝土橋梁溫度效應(yīng)計算的相關(guān)關(guān)鍵參數(shù)進行了實驗研究:設(shè)計了一種混凝土試件加熱裝置,通過直接加熱,驗證了混凝土變形與溫度變化的同步性;通過在能自由變形的混凝土試塊中埋入鋼弦式應(yīng)變計,實測太陽輻射作用下試塊內(nèi)部應(yīng)變分布,驗證了溫度自應(yīng)力計算時的平截面假定;提出了一種依靠埋入式混凝土應(yīng)變計測試混凝土線膨脹系數(shù)的簡易方法,采用簡易方法研究了負溫條件對線膨脹系數(shù)的影響,發(fā)現(xiàn)負溫下線膨脹系數(shù)出現(xiàn)劇增;利用加熱裝置配合液壓伺服動態(tài)疲勞試驗機,實測了混凝土溫度應(yīng)力和短期內(nèi)的應(yīng)力松弛系數(shù),并對溫度應(yīng)力的折減系數(shù)和組合問題提出了建議。采用有限元分析和現(xiàn)場實測相結(jié)合的方法,系統(tǒng)分析了水泥水化熱效應(yīng)、混凝土不均勻收縮、壁面負溫差和豎向荷載對混凝土空心墩豎向開裂的影響,結(jié)果表明:這4大因素的不同疊加作用是導致混凝土空心墩豎向開裂的直接原因;從性質(zhì)上看,混凝土矩形空心墩豎向裂縫主要屬于變形裂縫,防治時應(yīng)以預(yù)防措施和配筋防控措施為主,必要時采取裂縫處治措施。
[Abstract]:Current design codes for highway bridges in China stipulate the uniform temperature effect of concrete bridges roughly, which is in contradiction with the climatic conditions which are quite different nationwide. In addition, many concrete rectangular hollow piers appear vertical cracking defects. At present, the systematic analysis of causes and crack control research is still relatively scarce. This paper combines experimental research with numerical simulation to determine the temperature effect of concrete rectangular hollow piers, the key parameters of temperature effect calculation and vertical opening. The main research work and conclusions are as follows: Based on the long-term observation data of temperature, the relationship between the average temperature of concrete hollow pier and the external temperature is studied systematically, and two methods for predicting the average temperature range of Hollow Pier Based on the temperature data are proposed. According to the European structural design standard, it is suggested that the maximum recurrence period of 50 years should be selected, and the minimum daily mean temperature should be taken as the basic temperature, and 2oC should be added on the basis of the basic temperature. Through statistical analysis, the recommended effective temperature of concrete bridges at 194 weather stations in China is obtained, and compared with the current design code of highway bridges, the shortcomings are pointed out. Suggestions on the effect of uniform temperature of concrete bridges are put forward. The relationship between positive temperature difference and negative temperature difference of concrete hollow pier and meteorological conditions is studied systematically. Based on the measurement and finite element simulation of sunshine temperature field and cold wave cooling temperature field of concrete rectangular hollow pier, a two-dimensional temperature difference distribution model and a power function along the wall thickness direction of concrete rectangular hollow pier are proposed. The data of atmospheric transparency coefficient, diurnal temperature difference, maximum 24-hour cooling range of daily average temperature and daily average wind speed were collected from 20 representative sites in China. Proposed values of power function constant a and temperature effect depth B are given. The key parameters of temperature effect calculation of concrete bridge are experimentally studied. A heating device for concrete specimens is designed, which verifies the synchronization of concrete deformation and temperature change by direct heating. The strain distribution inside the specimen under solar radiation is measured by embedded steel wire strain gauge, which verifies the assumption of plane section when calculating the temperature self-stress. Thermal stress and stress relaxation coefficient of concrete in short term were measured by heating device combined with hydraulic servo dynamic fatigue testing machine, and suggestions on reduction coefficient and combination of thermal stress were put forward. The influence of mud hydration heat effect, uneven shrinkage of concrete, negative temperature difference of wall and vertical load on the vertical cracking of concrete hollow pier is studied. The results show that the vertical cracking of concrete hollow pier is directly caused by the different superposition of these four factors. Preventive measures and reinforcement control measures should be the main treatment measures, and crack treatment measures should be taken when necessary.
【學位授予單位】：長安大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：U443.22
本文編號：2211635
[Abstract]:Current design codes for highway bridges in China stipulate the uniform temperature effect of concrete bridges roughly, which is in contradiction with the climatic conditions which are quite different nationwide. In addition, many concrete rectangular hollow piers appear vertical cracking defects. At present, the systematic analysis of causes and crack control research is still relatively scarce. This paper combines experimental research with numerical simulation to determine the temperature effect of concrete rectangular hollow piers, the key parameters of temperature effect calculation and vertical opening. The main research work and conclusions are as follows: Based on the long-term observation data of temperature, the relationship between the average temperature of concrete hollow pier and the external temperature is studied systematically, and two methods for predicting the average temperature range of Hollow Pier Based on the temperature data are proposed. According to the European structural design standard, it is suggested that the maximum recurrence period of 50 years should be selected, and the minimum daily mean temperature should be taken as the basic temperature, and 2oC should be added on the basis of the basic temperature. Through statistical analysis, the recommended effective temperature of concrete bridges at 194 weather stations in China is obtained, and compared with the current design code of highway bridges, the shortcomings are pointed out. Suggestions on the effect of uniform temperature of concrete bridges are put forward. The relationship between positive temperature difference and negative temperature difference of concrete hollow pier and meteorological conditions is studied systematically. Based on the measurement and finite element simulation of sunshine temperature field and cold wave cooling temperature field of concrete rectangular hollow pier, a two-dimensional temperature difference distribution model and a power function along the wall thickness direction of concrete rectangular hollow pier are proposed. The data of atmospheric transparency coefficient, diurnal temperature difference, maximum 24-hour cooling range of daily average temperature and daily average wind speed were collected from 20 representative sites in China. Proposed values of power function constant a and temperature effect depth B are given. The key parameters of temperature effect calculation of concrete bridge are experimentally studied. A heating device for concrete specimens is designed, which verifies the synchronization of concrete deformation and temperature change by direct heating. The strain distribution inside the specimen under solar radiation is measured by embedded steel wire strain gauge, which verifies the assumption of plane section when calculating the temperature self-stress. Thermal stress and stress relaxation coefficient of concrete in short term were measured by heating device combined with hydraulic servo dynamic fatigue testing machine, and suggestions on reduction coefficient and combination of thermal stress were put forward. The influence of mud hydration heat effect, uneven shrinkage of concrete, negative temperature difference of wall and vertical load on the vertical cracking of concrete hollow pier is studied. The results show that the vertical cracking of concrete hollow pier is directly caused by the different superposition of these four factors. Preventive measures and reinforcement control measures should be the main treatment measures, and crack treatment measures should be taken when necessary.
【學位授予單位】：長安大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：U443.22
【參考文獻】
相關(guān)期刊論文 前10條
1 雷笑;葉見曙;王毅;;日照作用下混凝土箱梁的溫差代表值[J];東南大學學報(自然科學版);2008年06期
2 趙牡珍;薄壁箱形橋墩與橋塔設(shè)計的建議[J];國外橋梁;1996年02期
3 高小建;闞雪峰;楊英姿;;單面干燥條件下混凝土的收縮變形分布特征[J];硅酸鹽學報;2009年01期
4 戴吉春;董校輝;;高寒地區(qū)鋼筋混凝土簡支梁溫度變形的觀測與溫變系數(shù)的研究[J];黑龍江水利科技;2011年05期
5 吳勝興;;混凝土結(jié)構(gòu)溫度應(yīng)力計算必須考慮的因素[J];水利水電科技進展;1996年03期
6 李旦江,劉望亭;用原型觀測資料推求大壩混凝土的力學參數(shù)[J];水利學報;1992年07期
7 任翔;;混凝土橋塔溫度場的時變分析及溫度梯度模式研究[J];鐵道標準設(shè)計;2012年06期
8 張建榮;劉照球;;混凝土對流換熱系數(shù)的風洞實驗研究[J];土木工程學報;2006年09期
9 邱國全,夏艷君,楊鴻毅;晴天太陽輻射模型的優(yōu)化計算[J];太陽能學報;2001年04期
10 沈德建;申嘉鑫;黃杰;曹秀麗;;早齡期及硬化階段水泥基材料熱膨脹系數(shù)研究[J];水利學報;2012年S1期
相關(guān)博士學位論文 前3條
1 汪劍;大跨預(yù)應(yīng)力混凝土箱梁橋非荷載效應(yīng)及預(yù)應(yīng)力損失研究[D];湖南大學;2006年
2 彭友松;混凝土橋梁結(jié)構(gòu)日照溫度效應(yīng)理論及應(yīng)用研究[D];西南交通大學;2007年
3 武立群;混凝土箱梁和空心高墩溫度場及溫度效應(yīng)研究[D];重慶大學;2012年
相關(guān)碩士學位論文 前8條
1 曹少輝;貴州高墩大跨PC連續(xù)剛構(gòu)橋的溫度場分析與溫度效應(yīng)研究[D];長沙理工大學;2010年
2 張門哲;大跨預(yù)應(yīng)力混凝土斜拉橋施工控制及索塔溫度效應(yīng)分析[D];湖南大學;2004年
3 白劍;懸索橋施工過程溫度場測試及溫度效應(yīng)分析[D];長安大學;2004年
4 趙亮;鐵路橋墩溫度效應(yīng)有限元分析[D];重慶大學;2007年
5 趙志華;斜拉橋施工監(jiān)測監(jiān)控中的溫度因素影響研究[D];武漢理工大學;2008年
6 劉吉波;斜拉橋索塔溫度場分析及索塔裂縫溫變特性研究[D];武漢理工大學;2008年
7 謝雪梅;幸福源水庫雙線特大橋空心高墩溫度場試驗研究[D];重慶大學;2012年
8 周妞妞;薄壁空心高墩溫度效應(yīng)仿真分析[D];石家莊鐵道大學;2013年
，本文編號：2211635
本文鏈接：http://sikaile.net/kejilunwen/daoluqiaoliang/2211635.html
