本文關(guān)鍵詞： 腐蝕 預(yù)應(yīng)力混凝土梁 靜力性能 疲勞性能　出處：《大連理工大學(xué)》2013年博士論文　論文類型：學(xué)位論文

【摘要】：車輛超載和環(huán)境腐蝕是引起橋梁結(jié)構(gòu)使用壽命降低的兩個主要原因。車輛超載容易引起混凝土內(nèi)部發(fā)生疲勞損傷,環(huán)境腐蝕會致使橋梁結(jié)構(gòu)耐久性降低,從而進一步加重混凝土內(nèi)部損傷程度。本文結(jié)合科技部“863”計劃資助項目“基于疲勞和壽命的混凝土橋梁結(jié)構(gòu)設(shè)計方法”(2007AA11Z133),對腐蝕鋼絞線以及鋼絞線腐蝕后的部分預(yù)應(yīng)力混凝土梁開展了靜力和疲勞試驗研究與分析,主要研究內(nèi)容和結(jié)果如下： 1、通過對同批鋼絞線進行的靜力拉伸試驗和疲勞試驗,研究了腐蝕鋼絞線的靜力性能和疲勞性能。靜力拉伸試驗結(jié)果表明,鋼絞線的塑性變形能力、極限強度以及彈性模量隨腐蝕率的增加而衰減。疲勞試驗結(jié)果表明,鋼絞線的疲勞壽命隨腐蝕率的增長按指數(shù)規(guī)律衰減,腐蝕缺陷與疲勞荷載之間的耦合作用是導(dǎo)致疲勞壽命下降的主要原因,腐蝕對鋼絞線疲勞性能的影響遠比對鋼絞線的靜力性能影響大。通過試驗數(shù)據(jù)的回歸統(tǒng)計建立了腐蝕鋼絞線在靜載作用下的本構(gòu)關(guān)系模型與疲勞荷載作用下的S-N方程。 2、通過對同批鋼絞線腐蝕后的部分預(yù)應(yīng)力混凝土梁進行四點彎曲的靜載和疲勞試驗,研究了腐蝕對試驗梁靜力和疲勞性能的影響。靜載試驗結(jié)果表明,在靜載試驗中,鋼絞線的腐蝕不僅導(dǎo)致部分預(yù)應(yīng)力混凝土梁的破壞形態(tài)由延性破壞轉(zhuǎn)為脆性破壞,還影響了腐蝕梁的開裂荷載大小,腐蝕對延性的影響遠比對極限承載力影響顯著。疲勞試驗結(jié)果表明,腐蝕梁的疲勞破壞是由腐蝕鋼絞線的疲勞斷裂引起的,試驗梁的疲勞壽命與疲勞強度隨著鋼絞線腐蝕程度的增加而顯著降低。根據(jù)試驗結(jié)果回歸建立了疲勞荷載下鋼絞線腐蝕后的部分預(yù)應(yīng)力混凝土梁跨中撓度和混凝土殘余應(yīng)變的計算公式。此外,鑒于超載對既有橋梁結(jié)構(gòu)的影響,本章還對一種新型預(yù)應(yīng)力混凝土梁開展了單調(diào)荷載與循環(huán)荷載下的受力性能研究,結(jié)果表明,該種類型梁在單調(diào)與循環(huán)荷載作用下均有良好的承載能力和延性,具有良好的應(yīng)用前景。 3、基于內(nèi)力平衡方程和平截面假定,推導(dǎo)了試驗梁的跨中撓度與鋼筋應(yīng)變關(guān)于混凝土受壓區(qū)邊緣應(yīng)變的表達式,并引入分級加應(yīng)變法對靜載作用下鋼絞線腐蝕后的部分預(yù)應(yīng)力混凝土梁的受力過程進行分析。確立了受壓區(qū)混凝土以及受拉鋼筋(包括鋼絞線)疲勞本構(gòu)關(guān)系及疲勞破壞準(zhǔn)則,運用分段線性方法并結(jié)合靜載的分級應(yīng)變法,建立了鋼絞線腐蝕后的部分預(yù)應(yīng)力混凝土梁的疲勞損傷全過程分析方法。 4、運用ANSYS有限元軟件對鋼絞線腐蝕后的預(yù)應(yīng)力混凝土梁在靜力荷載下的受力行為進行了數(shù)值分析,分析了鋼絞線腐蝕對預(yù)應(yīng)力混凝土梁的靜力性能影響,并與試驗結(jié)果進行比較。根據(jù)Corten-Dolan累積損傷理論與ANSYS中的疲勞分析模塊對三級變幅疲勞荷載下的試驗梁進行了等效疲勞壽命預(yù)測。
[Abstract]:Vehicle overload and corrosion is caused by two main reasons for the reduction of the service life of the bridge structure. Overloading easily lead to fatigue damage of concrete, corrosion will cause the bridge structure durability is reduced, which further aggravate the damage degree of concrete. Combined with the Ministry of science and technology "863" project "the design method of concrete bridge structure and fatigue based on life" (2007AA11Z133), the corrosion of steel strand and partially prestressed concrete beams after corrosion of steel strand is carried out static and fatigue test research and analysis, the main research contents and results are as follows:
1, through the static tensile test and fatigue test on the same batch of steel strand, of steel strands corroded the static and fatigue performance. Static tensile test results show that the plastic deformation capacity of steel strand, increase the ultimate strength and modulus of elasticity with corrosion rate and attenuation. The fatigue test results show that the fatigue life of steel with the wire corrosion rate growth exponentially, the coupling effect between defects and fatigue corrosion is the main cause of the decrease of fatigue life, corrosion effect on fatigue performance of steel wire than the impact of static performance of steel strand. By the statistical test data established the corrosion of steel strands under static load the constitutive model and fatigue loads of the S-N equation.
2, through four point bending static and fatigue test of partially prestressed concrete with steel wires after corrosion of the beam, study the corrosion effects on static and fatigue test beams. The static load test results show that in the static load test, the corrosion of steel strand not only leads to the damage form of partially prestressed concrete beams the ductile fracture to brittle failure, but also affect the size of corrosion cracking load of beams. The influence of corrosion on ductility than the ultimate bearing capacity was significant. The fatigue test results show that the corrosion fatigue damage of beam is caused by fatigue fracture corrosion of steel strand, the fatigue life and the fatigue strength of test beams decreased significantly with increase the degree of corrosion of steel strand. According to the results of regression is built of partially prestressed concrete beams after corrosion of steel strand under fatigue load deflection and residual strain in concrete span calculation Formula. In addition, the overloading effects of existing bridge, this chapter makes a model of prestressed concrete beam is studied. The stress performance under monotonic load and cyclic load. The results show that this kind of beams under monotonic and cyclic loading effect has good bearing capacity and ductility, and has good application prospect.
3, assuming that the internal force balance equation is deduced based on the plane section, the test beam deflection and strain of steel bar on the edge strain of concrete in compression zone, and introduce the classification process with stress analysis under static load on Corrosion of steel wire after partially prestressed concrete beam is established. The reform of concrete compression zone and the tensile steel (including steel strand) fatigue constitutive model and fatigue failure criterion, using piecewise linear method and combining the classification of static strain, established the corrosion of steel strands of partially prestressed concrete beams after fatigue damage process analysis method.
4, using the numerical analysis of prestressed concrete beams after corrosion of steel strands in the static load behavior of ANSYS finite element software, analyzes the influence of corrosion of steel strands static performance of prestressed concrete beam, and compared with the experimental results. According to the test of Corten-Dolan cumulative fatigue damage theory and analysis module of ANSYS the three variable amplitude fatigue loading beam predicted equivalent fatigue life.

【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：TU378.2

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