锈蚀钢筋混凝土粘结性能全过程分析
发布时间：2019-06-18 12:58
【摘要】：在混凝土结构百年发展史中,虽然耐久性问题很早就已被人们认识到,但是,由于问题的复杂性以及缺乏先进的试验技术手段等方面的原因,至今人们对钢筋混凝土结构耐久性的认识还远不够充分和彻底。因此,对腐蚀环境下钢筋混凝土结构耐久性做进一步深入的研究是十分必要的。本文基于以往锈蚀钢筋混凝土结构力学性能的研究中存在的不足,采用试验研究和理论分析相结合的方法,进行了以下内容的研究工作:(1)为探讨腐蚀环境对钢筋混凝土梁粘结性能的影响,本文对6根支座处受拉纵筋锚固长度为零的钢筋混凝土试验梁进行了三分点加载的粘结破坏试验研究,其中1根为未经过氯盐溶液浸泡的对比试验梁。首先,将5根试验梁浸泡在氯盐溶液中并通过硅控整流器施加直流电,进行加速腐蚀试验(每根试验梁腐蚀时间的设定是依据其各自事先给定的钢筋目标锈蚀量和Faraday定律进行预估的),并观察每根腐蚀后钢筋混凝土梁底部的锈胀裂缝,建立裂缝宽度与钢筋锈蚀率之间的关系。然后,对每根钢筋混凝土梁进行三分点加载试验,探讨在三分点加载荷载作用下钢筋锈蚀损伤对试验梁荷载-变形曲线的影响,并观察加载裂缝发展规律和最终破坏形态。给出了荷载-挠度曲线、荷载-跨中截面混凝土应变与钢筋应变历程曲线以及平均粘结应力-滑移历程曲线。试验结果表明:锈胀裂缝发生在试验梁底部受拉钢筋附近,而且,锈蚀损伤越大,锈胀裂缝宽度越宽;试验梁跨中应变在初始加载过程中沿梁高均呈现线性变化,此时梁截面仍符合平截面假设。随着荷载进一步加大,跨中混凝土应变沿梁高逐步出现非线性分布,截面也不再符合平截面假设。随着锈蚀率增加,中和轴不断上升;在加载过程中,加载裂缝出现顺序为从跨中向支座两端发散,从混凝土梁底部向顶部蔓延;随着荷载增加,支座处沿顺筋方向出现粘结撕裂裂缝,最终导致试验梁产生粘结破坏,出现滑移;在锈蚀初始状态,试验梁发生粘结破坏的极限承载能力有所提高,随着锈蚀率的不断增大,极限承载能力逐渐降低;当锈蚀达到一定程度之后,极限承载能力低于无锈蚀试验梁的极限承载能力,并随着锈蚀率进一步增加而继续递减。(2)介绍了ANSYS程序中实现钢筋混凝土粘结性能的非线性有限元分析方法和原理。分别以钢筋混凝土拔出试件和钢筋混凝土梁构件作为算例进行了ANSYS计算分析,对ANSYS中钢筋混凝土有限元分析从前处理到后处理的全过程进行了介绍、调试和验证,并对ANSYS程序的分析结果与已有试验结果进行对比分析。ANSYS程序的调试、验证结果表明,ANSYS程序能够较方便地用于对混凝土结构进行非线性有限元分析,而且建模方便,计算结果与理论结果吻合较好。(3)结合本文试验得到的钢筋锈蚀程度对粘结强度和钢筋力学性能的影响,构建了相应的锈蚀钢筋混凝土梁ANSYS有限元数值模型,数值分析结果与试验结果吻合较好。在有限元数值解和试验结果吻合的前提下,用有限元技术对锈蚀钢筋混凝土试验梁的粘结破坏全过程进行了系统的数值模拟,给出了锈蚀钢筋混凝土梁在加载全过程中的粘结滑移分布、裂缝发展、Von Mises应力云分布、混凝土应变和应力分布以及试验梁加载形变过程。研究成果为分析锈蚀钢筋混凝土梁耐久性提供了新的参考依据。
[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.
【学位授予单位】：华东交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375
[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.
【学位授予单位】：华东交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375
【参考文献】
相关期刊论文 前10条
1 何化南;杨Z赯，
本文编号：2501508
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