【摘要】：在混凝土結(jié)構(gòu)百年發(fā)展史中,雖然耐久性問題很早就已被人們認(rèn)識(shí)到,但是,由于問題的復(fù)雜性以及缺乏先進(jìn)的試驗(yàn)技術(shù)手段等方面的原因,至今人們對(duì)鋼筋混凝土結(jié)構(gòu)耐久性的認(rèn)識(shí)還遠(yuǎn)不夠充分和徹底。因此,對(duì)腐蝕環(huán)境下鋼筋混凝土結(jié)構(gòu)耐久性做進(jìn)一步深入的研究是十分必要的。本文基于以往銹蝕鋼筋混凝土結(jié)構(gòu)力學(xué)性能的研究中存在的不足,采用試驗(yàn)研究和理論分析相結(jié)合的方法,進(jìn)行了以下內(nèi)容的研究工作:(1)為探討腐蝕環(huán)境對(duì)鋼筋混凝土梁粘結(jié)性能的影響,本文對(duì)6根支座處受拉縱筋錨固長(zhǎng)度為零的鋼筋混凝土試驗(yàn)梁進(jìn)行了三分點(diǎn)加載的粘結(jié)破壞試驗(yàn)研究,其中1根為未經(jīng)過氯鹽溶液浸泡的對(duì)比試驗(yàn)梁。首先,將5根試驗(yàn)梁浸泡在氯鹽溶液中并通過硅控整流器施加直流電,進(jìn)行加速腐蝕試驗(yàn)(每根試驗(yàn)梁腐蝕時(shí)間的設(shè)定是依據(jù)其各自事先給定的鋼筋目標(biāo)銹蝕量和Faraday定律進(jìn)行預(yù)估的),并觀察每根腐蝕后鋼筋混凝土梁底部的銹脹裂縫,建立裂縫寬度與鋼筋銹蝕率之間的關(guān)系。然后,對(duì)每根鋼筋混凝土梁進(jìn)行三分點(diǎn)加載試驗(yàn),探討在三分點(diǎn)加載荷載作用下鋼筋銹蝕損傷對(duì)試驗(yàn)梁荷載-變形曲線的影響,并觀察加載裂縫發(fā)展規(guī)律和最終破壞形態(tài)。給出了荷載-撓度曲線、荷載-跨中截面混凝土應(yīng)變與鋼筋應(yīng)變歷程曲線以及平均粘結(jié)應(yīng)力-滑移歷程曲線。試驗(yàn)結(jié)果表明:銹脹裂縫發(fā)生在試驗(yàn)梁底部受拉鋼筋附近,而且,銹蝕損傷越大,銹脹裂縫寬度越寬;試驗(yàn)梁跨中應(yīng)變?cè)诔跏技虞d過程中沿梁高均呈現(xiàn)線性變化,此時(shí)梁截面仍符合平截面假設(shè)。隨著荷載進(jìn)一步加大,跨中混凝土應(yīng)變沿梁高逐步出現(xiàn)非線性分布,截面也不再符合平截面假設(shè)。隨著銹蝕率增加,中和軸不斷上升;在加載過程中,加載裂縫出現(xiàn)順序?yàn)閺目缰邢蛑ё鶅啥税l(fā)散,從混凝土梁底部向頂部蔓延;隨著荷載增加,支座處沿順筋方向出現(xiàn)粘結(jié)撕裂裂縫,最終導(dǎo)致試驗(yàn)梁產(chǎn)生粘結(jié)破壞,出現(xiàn)滑移;在銹蝕初始狀態(tài),試驗(yàn)梁發(fā)生粘結(jié)破壞的極限承載能力有所提高,隨著銹蝕率的不斷增大,極限承載能力逐漸降低;當(dāng)銹蝕達(dá)到一定程度之后,極限承載能力低于無銹蝕試驗(yàn)梁的極限承載能力,并隨著銹蝕率進(jìn)一步增加而繼續(xù)遞減。(2)介紹了ANSYS程序中實(shí)現(xiàn)鋼筋混凝土粘結(jié)性能的非線性有限元分析方法和原理。分別以鋼筋混凝土拔出試件和鋼筋混凝土梁構(gòu)件作為算例進(jìn)行了ANSYS計(jì)算分析,對(duì)ANSYS中鋼筋混凝土有限元分析從前處理到后處理的全過程進(jìn)行了介紹、調(diào)試和驗(yàn)證,并對(duì)ANSYS程序的分析結(jié)果與已有試驗(yàn)結(jié)果進(jìn)行對(duì)比分析。ANSYS程序的調(diào)試、驗(yàn)證結(jié)果表明,ANSYS程序能夠較方便地用于對(duì)混凝土結(jié)構(gòu)進(jìn)行非線性有限元分析,而且建模方便,計(jì)算結(jié)果與理論結(jié)果吻合較好。(3)結(jié)合本文試驗(yàn)得到的鋼筋銹蝕程度對(duì)粘結(jié)強(qiáng)度和鋼筋力學(xué)性能的影響,構(gòu)建了相應(yīng)的銹蝕鋼筋混凝土梁ANSYS有限元數(shù)值模型,數(shù)值分析結(jié)果與試驗(yàn)結(jié)果吻合較好。在有限元數(shù)值解和試驗(yàn)結(jié)果吻合的前提下,用有限元技術(shù)對(duì)銹蝕鋼筋混凝土試驗(yàn)梁的粘結(jié)破壞全過程進(jìn)行了系統(tǒng)的數(shù)值模擬,給出了銹蝕鋼筋混凝土梁在加載全過程中的粘結(jié)滑移分布、裂縫發(fā)展、Von Mises應(yīng)力云分布、混凝土應(yīng)變和應(yīng)力分布以及試驗(yàn)梁加載形變過程。研究成果為分析銹蝕鋼筋混凝土梁耐久性提供了新的參考依據(jù)。
[Abstract]:in that history of the 100-year development of the concrete structure, the durability problem has long been recognized by people, but due to the complexity of the problem and the lack of advanced experimental technical means, So far, the cognition of the durability of the reinforced concrete structure is far from sufficient and thorough. Therefore, it is necessary to study the durability of reinforced concrete structures in the corrosive environment. Based on the defects in the research of the mechanical properties of the conventional corrosion-resistant reinforced concrete structure, the following research work is carried out by using the combination of the experimental research and the theoretical analysis: (1) to study the effect of the corrosion environment on the bonding performance of the reinforced concrete beam, In this paper, the test of three-point loading of reinforced concrete test beam with the anchorage length of the tensile longitudinal bar at the six support is studied, and one of them is the contrast test beam which is not soaked by the chlorine salt solution. First, five test beams are immersed in a chlorine salt solution and a direct current is applied through a silicon controlled rectifier to conduct an accelerated corrosion test (the setting of the corrosion time of each test beam is estimated in accordance with the respective pre-given corrosion amount of the reinforcement target and the Faraday's law), And the relationship between the crack width and the corrosion rate of the steel bar is established. Then, a three-point load test is carried out on each reinforced concrete beam, and the influence of the corrosion damage of the steel bar on the load-deformation curve of the test beam under the load action of the three-point load is discussed, and the development law of the loading crack and the final damage form are observed. The load-deflection curve, the strain of the concrete in the load-span and the strain history of the steel bar and the average bond stress-slip course are given. The test results show that the rust-expansion crack is near the tension steel bar at the bottom of the test beam, and the greater the corrosion damage, the wider the width of the rust-expanding crack; the strain in the span of the test beam shows a linear change along the height of the beam during the initial loading process, and the cross-section of the beam still meets the assumption of the flat-section. As the load is further increased, the non-linear distribution of the concrete strain along the beam gradually occurs, and the cross-section is no longer in line with the assumption of the flat section. As the corrosion rate is increased, the middle and the shafts are continuously increasing; during the loading process, the loading crack is arranged to diverge from the middle to the two ends of the support, and spread from the bottom of the concrete beam to the top; and as the load is increased, the support is bonded with the tearing crack along the direction of the rib, In the initial state, the ultimate bearing capacity of the test beam is increased, and with the increasing of the corrosion rate, the ultimate bearing capacity is gradually reduced; and when the rust reaches a certain degree, The ultimate bearing capacity is lower than the ultimate bearing capacity of the non-corrosion test beam and continues to decrease with the further increase of the corrosion rate. (2) The non-linear finite element analysis method and principle of the adhesive performance of reinforced concrete in the ANSYS program are introduced. The finite element analysis of the reinforced concrete in ANSYS is introduced, debugged and verified by the finite element analysis of the reinforced concrete in ANSYS. And the analysis result of the ANSYS program is compared and analyzed with the existing test results. The test results of the ANSYS program show that the ANSYS program can be used for nonlinear finite element analysis of the concrete structure, and the modeling is convenient, and the result of the calculation is in good agreement with the theoretical results. (3) The effect of the corrosion degree of the steel bar on the bond strength and the mechanical property of the steel bar is studied in the paper. The finite element numerical model of the corresponding corroded reinforced concrete beam is constructed. The result of the numerical analysis is in good agreement with the test results. On the premise that the finite element numerical solution and the test result are in good agreement, the whole process of the bond failure of the corroded reinforced concrete test beam is simulated by the finite element technique, and the bonding slip distribution and the crack development of the corroded reinforced concrete beam during the loading process are given, Von Mises stress cloud distribution, concrete strain and stress distribution, and test beam loading and deformation process. The research results provide a new reference for the analysis of the durability of the corroded reinforced concrete beam.
【學(xué)位授予單位】：華東交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU375

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 何化南;楊Z赯，

本文編號(hào)：2501508