荷载和环境作用下锈蚀钢筋混凝土柱的力学性能

发布时间：2018-04-12 23:07

本文选题：钢筋混凝土柱 + 荷载与环境　；参考：《浙江大学》2015年博士论文

【摘要】：钢筋混凝土结构均是在荷载和环境共同作用下工作。柱是结构的竖向承重构件,支撑着梁板等上部结构,柱子的破坏往往比其它构件破坏造成的危害更加严重。氯盐侵蚀是导致钢筋混凝土结构服役性能劣化的重要原因之一。本文以柱为研究对象,围绕荷载和环境共同作用下锈蚀钢筋混凝土柱的力学性能,进行了以下研究工作： (1)为选择科学合理的主筋和箍筋同时锈蚀的加速试验方法,对相同试件采用不同的接线方式进行通电加速锈蚀和承载力试验,对比了不同接线锈蚀方法试件的锈蚀钢筋质量损失、溢锈分布、溢锈颜色、锈胀裂缝分布和发展规律,分析了锈蚀钢筋的表面形态和锈蚀产物形貌,研究了主筋与箍筋连接和接线方式对锈蚀试件极限承载力、荷载-位移、破坏特征等宏观力学性能的影响。 (2)为量化仅箍筋锈蚀对混凝土柱承载力的影响,对采用外加电流法获得的仅箍筋锈蚀的钢筋混凝土短柱进行轴压承载力试验,分析了箍筋锈胀裂缝的分布规律,比较了箍筋锈蚀对柱极限承载力和破坏特征等宏观力学性能的影响,建立了考虑箍筋锈蚀引起的保护层剥落、箍筋对混凝土约束能力降低、箍筋对主筋支撑作用降低等因素的箍筋锈蚀轴压混凝土短柱承载力模型。 (3)为研究荷载和环境共同作用下钢筋混凝土柱的力学性能,提出了荷载和环境共同作用下钢筋混凝土柱力学性能的试验方法,分别采用自平衡和外加电流的方法对柱施加持续荷载和对柱内主筋与箍筋进行加速锈蚀来模拟荷载和环境的共同作用；开发了由支撑系统、垂直升降系统和水平移动系统组成的受压柱试验的加载定位装置；通过对持载和锈蚀作用下轴心、小偏心和大偏心共30根柱的承载力试验,分析了荷载和环境共同作用对柱中钢筋锈蚀的影响及锈胀裂缝的分布规律,比较了偏心距、持载水平和锈蚀率对锈蚀钢筋混凝土柱宏观力学性能的影响,研究了荷载和环境共同作用下锈蚀钢筋混凝土柱的破坏特征。 (4)基于荷载和环境共同作用下锈蚀钢筋混凝土的承载力试验,分析了锈蚀钢筋混凝土柱承载力的影响因素,综合考虑箍筋锈蚀对主筋支撑作用降低进而对主筋屈曲承载力的影响、主筋和箍筋锈蚀引起保护层剥落、自身截面面积减小和强度的改变以及长期荷载作用的影响,采用变刚度的弹簧模拟箍筋锈蚀区段内箍筋对主筋的约束,分别建立了锈蚀钢筋混凝土轴压柱和偏压柱的承载力模型。 (5)为研究钢筋混凝土柱的损伤破坏全过程,借助液压加载系统和声发射(AE)系统测试了非锈蚀和锈蚀钢筋混凝土偏压柱在荷载作用下的声发射参数,对比分析了非锈蚀和锈蚀柱的声发射特征及其时空演化规律,基于声发射幅值信号的裕度值评价了非锈蚀和锈蚀钢筋混凝土偏压柱的损伤状况,给出了基于声发射能量相对变化参数表示的损伤因子表达式。
[Abstract]:Reinforced concrete structures work under the combined action of load and environment.Column is the vertical bearing member of structure, which supports the upper structure such as beam and slab. The damage of column is more serious than that of other members.Chloride erosion is one of the important causes of deterioration of service performance of reinforced concrete structures.In this paper, columns are taken as the research object, and the following research work is carried out around the mechanical properties of corroded reinforced concrete columns under the combined action of load and environment.In order to select scientific and reasonable accelerated corrosion test method of main reinforcement and stirrups at the same time, electric accelerated corrosion and bearing capacity tests are carried out on the same specimens with different connection modes.In this paper, the quality loss, distribution, color, crack distribution and development of corroded steel bars with different wiring corrosion methods are compared, and the surface morphology and morphology of corrosion products of corroded steel bars are analyzed.The effects of connection and connection between main reinforcement and stirrups on the ultimate bearing capacity, load-displacement and failure characteristics of corroded specimens were studied.In order to quantify the effect of stirrups corrosion only on the bearing capacity of concrete columns, the axial bearing capacity tests of reinforced concrete short columns with only stirrups corrosion obtained by external current method are carried out, and the distribution law of stirrups corrosion cracks is analyzed.The effects of stirrups corrosion on the ultimate bearing capacity and failure characteristics of columns are compared. The protection layer spalling caused by stirrups corrosion is established, and the restraint ability of stirrups to concrete is reduced.The bearing capacity model of corroded concrete short columns with stirrups corroded by stirrups and other factors which reduce the effect of stirrups on the support of main tendons.In order to study the mechanical properties of reinforced concrete columns under the combined action of load and environment, a test method for the mechanical properties of reinforced concrete columns under the combined action of load and environment is put forward.In order to simulate the interaction of load and environment, the self-balancing and applied electric current are applied to the column and the main reinforcement and stirrups in the column are corroded to simulate the interaction between the load and the environment, and the bracing system is developed.A loading and positioning device for the compression column test consisting of a vertical lifting system and a horizontal moving system. The bearing capacity of a total of 30 columns with small eccentricity and large eccentricity under the action of holding load and corrosion is tested.The effects of load and environment on the corrosion of steel bars and the distribution of corrosion cracks in columns are analyzed. The effects of eccentricity, load holding level and corrosion rate on the macroscopic mechanical properties of corroded reinforced concrete columns are compared.The failure characteristics of corroded reinforced concrete columns under the combined action of load and environment are studied.4) based on the bearing capacity test of corroded reinforced concrete under the combined action of load and environment, the factors affecting the bearing capacity of corroded reinforced concrete columns are analyzed.Considering the effect of stirrups corrosion on the buckling capacity of the main reinforcement, the corrosion of the main reinforcement and stirrups cause the exfoliation of the protective layer, the decrease of the cross section area and the change of the strength, as well as the effect of the long-term load.The bearing capacity models of corroded reinforced concrete columns under axial compression and eccentric compression are established by using spring with variable stiffness to simulate the constraints of stirrups on the main reinforcement in the corroded section of stirrups.In order to study the whole process of damage and failure of reinforced concrete columns, the acoustic emission parameters of non-corroded and corroded reinforced concrete columns under load are measured by hydraulic loading system and acoustic emission (AE) system.The acoustic emission characteristics of non-rust and corroded columns and their space-time evolution laws are compared and analyzed. The damage status of non-corroded and corroded reinforced concrete columns is evaluated based on the margin of acoustic emission amplitude signals.The expression of damage factor based on the relative variation parameter of acoustic emission energy is given.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU375.3

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