【摘要】：預應(yīng)力混凝土結(jié)構(gòu)與普通混凝土結(jié)構(gòu)相比具有明顯的優(yōu)越性能，因此被廣泛地應(yīng)用到土木、建筑、水利和交通工程等各個領(lǐng)域。與其它結(jié)構(gòu)一樣，預應(yīng)力混凝土結(jié)構(gòu)長期在侵蝕環(huán)境作用下也會出現(xiàn)耐久性失效，，近年來預應(yīng)力混凝土結(jié)構(gòu)在環(huán)境侵蝕作用下的耐久性問題已成為結(jié)構(gòu)工程領(lǐng)域的研究熱點之一。 從氣候條件來看，我國有相當大的地區(qū)處于嚴寒地帶，有調(diào)查指出我國東北地區(qū)很多水工建筑物、橋梁的混凝土或預應(yīng)力混凝土結(jié)構(gòu)局部或大面積地遭受凍融破壞，造成重大經(jīng)濟損失。對長期處于嚴寒環(huán)境中的預應(yīng)力混凝土結(jié)構(gòu)，凍融作用是影響結(jié)構(gòu)耐久性一個非常重要的因素，其抗凍性已引起工程界的重視，另一方面，預應(yīng)力混凝土結(jié)構(gòu)在服役期內(nèi)承受著靜載和頻繁的反復荷載作用，如結(jié)構(gòu)自重、車輛荷載、隨機波浪力等，其抗力將隨損傷的累積而衰減最終導致結(jié)構(gòu)功能退化或失效。 目前如何對已建及新建預應(yīng)力混凝土結(jié)構(gòu)在凍融環(huán)境下的疲勞性能進行分析和評估是工程界急需解決的問題，基于此，本文結(jié)合國家自然科學基金資助課題“雙指標侵蝕環(huán)境作用下預應(yīng)力結(jié)構(gòu)耐久性試驗與壽命預測研究”，通過對預應(yīng)力混凝土構(gòu)件在凍融與疲勞荷載交替作用下的試驗研究，研究了預應(yīng)力混凝土構(gòu)件在凍融環(huán)境下的疲勞性能。本文完成的主要工作如下： 1.對16根預應(yīng)力混凝土試件進行了試驗研究，探討了混凝土強度、預應(yīng)力度、凍融與疲勞交替次數(shù)比及疲勞荷載上限的大小對試件外觀形態(tài)、動彈性模量、跨中撓度、混凝土和鋼筋應(yīng)變變化的影響； 2.通過正交試驗分析方法研究了凍融疲勞交替次數(shù)比、疲勞荷載上限和預應(yīng)力度對動彈性模量衰減速率影響的大��；驗證了對于試件動彈性模量的衰減，凍融與荷載疲勞之間存在著一定的交互作用； 3..基于疲勞損傷累積理論以動彈性模量為損傷指標建立了凍融疲勞作用下構(gòu)件的損傷模型并驗證了模型的適用性； 4.對凍融與荷載疲勞后的試件截面進行了理論應(yīng)力分析，并將理論值與試驗值進行了對比分析； 5.建立了基于試件動彈性模量衰減和考慮普通鋼筋疲勞斷裂的壽命預測模型。 本課題對預應(yīng)力混凝土試件在凍融與疲勞荷載交替作用下的耐久性進行了研究，研究成果對于我國北方寒冷地區(qū)已建及新建工程在凍融環(huán)境下的疲勞耐久性進行評估具有較高的理論意義和實用價值。
[Abstract]:Compared with ordinary concrete structure, prestressed concrete structure has obvious superior performance, so it is widely used in civil, building, water conservancy, traffic engineering and other fields. Like other structures, prestressed concrete structures will have durability failure under the action of erosive environment for a long time. In recent years, the durability of prestressed concrete structures under environmental erosion has become one of the research hotspots in the field of structural engineering. From the point of view of climatic conditions, quite a large area of our country is in the severe cold zone. Some investigations have pointed out that many hydraulic structures in Northeast China, concrete or prestressed concrete structures of bridges are subjected to freeze-thaw damage locally or in a large area. Cause great economic losses. For prestressed concrete structures in severe cold environment for a long time, freeze-thaw is a very important factor affecting the durability of structures, and its frost resistance has attracted the attention of the engineering community. On the other hand, Prestressed concrete structure is subjected to static load and frequent repeated load during the service period, such as structural self-weight, vehicle load, random wave force and so on. The resistance of prestressed concrete structure will decline with the accumulation of damage and eventually lead to the degradation or failure of structural function. At present, how to analyze and evaluate the fatigue performance of newly built prestressed concrete structures in freeze-thaw environment is an urgent problem to be solved in the engineering field. In this paper, based on the project supported by the National Natural Science Foundation of China, "Research on durability Test and Life Prediction of Prestressed structures under the Action of double Indexes erosion Environment", the experimental study of prestressed concrete members under the alternating action of freeze-thaw and fatigue loads is carried out. The fatigue behavior of prestressed concrete members in freeze-thaw environment is studied. The main work accomplished in this paper is as follows: 1. Sixteen prestressed concrete specimens are tested and studied, and the effects of concrete strength, prestress, alternating times ratio of freeze-thaw and fatigue and the upper limit of fatigue load on the appearance, dynamic elastic modulus and mid-span deflection of the specimens are discussed. The influence of strain change of concrete and steel bar; 2. The effects of freeze-thaw fatigue alternation ratio, fatigue load upper limit and prestress on the attenuation rate of dynamic elastic modulus were studied by orthogonal test. It is verified that there is a certain interaction between freeze-thaw and load fatigue for the attenuation of dynamic elastic modulus of specimens. Based on the fatigue damage accumulation theory, the damage model of components under freeze-thaw fatigue is established with dynamic elastic modulus as damage index, and the applicability of the model is verified. The theoretical stress analysis of the section of the specimen after freeze-thaw and load fatigue is carried out, and the theoretical value is compared with the experimental value. 5. A life prediction model based on dynamic elastic modulus attenuation and fatigue fracture of ordinary steel bar is established. In this paper, the durability of prestressed concrete specimens under the alternating action of freeze-thaw and fatigue loads is studied. The research results have high theoretical significance and practical value for evaluating the fatigue durability of new and built projects in cold areas of northern China under freeze-thaw environment.
【學位授予單位】：江蘇科技大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：TU378

【參考文獻】

相關(guān)期刊論文 前10條

1 呂海燕,戴公連,李德建;預應(yīng)力混凝土梁在疲勞荷載作用下的變形[J];長沙鐵道學院學報;1998年01期

2 張倩倩;孫偉;劉加平;;混凝土模擬液中臨界氯離子濃度影響因素分析[J];東南大學學報(自然科學版);2010年S2期

3 關(guān)宇剛,孫偉,繆昌文;基于可靠度與損傷理論的混凝土壽命預測模型Ⅱ:模型驗證與應(yīng)用[J];硅酸鹽學報;2001年06期

4 鄒超英;趙娟;梁鋒;巴恒靜;;凍融環(huán)境下混凝土應(yīng)力-應(yīng)變關(guān)系的試驗研究[J];哈爾濱工業(yè)大學學報;2007年02期

5 劉榮桂;付凱;顏庭成;;基于損傷理論的預應(yīng)力混凝土凍融破壞研究[J];混凝土;2007年01期

6 劉榮桂;高嵩;王大軍;賀健;;預應(yīng)力混凝土在凍融作用下的疲勞性能分析及可靠度研究[J];混凝土;2009年11期

7 葉英華;馬彬;孫洋;;鹽凍損傷鋼筋混凝土純彎構(gòu)件截面非線性分析[J];交通運輸工程學報;2009年06期

8 劉榮桂;付凱;顏庭成;陳妤;;預應(yīng)力混凝土結(jié)構(gòu)在凍融損傷條件下的疲勞壽命預測模型研究[J];建筑結(jié)構(gòu)學報;2009年03期

9 何世欽;貢金鑫;金峰;孫曉燕;;銹蝕與凍融循環(huán)下鋼筋與混凝土粘結(jié)退化性能[J];水力發(fā)電學報;2009年02期

10 何世欽,貢金鑫,趙國藩;凍融循環(huán)下混凝土中氯離子的擴散性[J];水利水運工程學報;2004年04期

相關(guān)博士學位論文 前2條

1 覃麗坤;高溫及凍融循環(huán)后混凝土多軸強度和變形試驗研究[D];大連理工大學;2003年

2 冀曉東;凍融后混凝土力學性能及鋼筋混凝土粘結(jié)性能的研究[D];大連理工大學;2007年

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