摘 要

混凝土结构早在古罗马时期就已经被发明出来，并应用到大型建筑工程中，现在建筑中，钢筋混凝土建筑技术已经较为成熟，各种形式的结构层出不穷，但是随着时间的推移，环境介质的侵蚀，耐久性问题逐渐暴露出来，空气中的碳进入混凝土引起碳化，产生微裂缝，水分进入，为钢筋的电化学锈蚀提供环境，钢筋逐渐锈蚀，严重导致钢筋锈断或者混凝土劣化等破坏现象。钢筋混凝土柱使用纵筋和箍筋组成的钢筋笼作为骨架，箍筋相对纵筋来说，距离截面边缘更近，混凝土保护层厚度更小，更容易受到环境的侵蚀而发生锈蚀，而纵筋作为主要的受力构件直接承受荷载，纵筋的锈蚀对于锈蚀构件的承载力影响较为严重，纵筋箍筋的锈蚀产生的锈胀产物，使得混凝土产生裂缝，部分外围混凝土直接退出工作，锈蚀造成承受荷载的混凝土截面面积减小，箍筋的锈蚀导致纵筋和核心区混凝土所受的横向约束减弱，构件更容易发生变形，承载能力下降。实际工程中，由于结构所处的环境及自身结构的差异，导致产生不同的锈蚀方式，如部分结构柱外侧容易遭到雨水环境的侵蚀，容易发生仅单侧纵筋的锈蚀，部分保护层厚度较大的结构仅发生箍筋的锈蚀，但实际中大部分结构发生箍筋纵筋均锈蚀的情况，不同的锈蚀方式对于结构的承载力、延性、刚度等力学性能影响存在差异。本文搜集不同的锈蚀钢筋混凝土轴压试验数据，通过数据的汇总绘图，集中分析不同的锈蚀方式对于混凝土柱力学性能的影响规律，并进行纵向和横向的数据对比，探究不同锈蚀方式下混凝土柱力学性能变化规律，同时通过理论分析与实际数据拟合，建立不同锈蚀方式下混凝土柱承载力公式，对于实际工程中锈蚀构件承载力预估计算和维修加固提供了一定得参考。

本文搜集近70篇国内外锈蚀钢筋混凝土轴心受压相关试验论文，利用getdate数据提取软件汇集主要试验数据，通过origin将处理后的归一化试验数据绘图，集中分析不同锈蚀方式下混凝土柱力学性能退化规律，结论如下：随着锈蚀率的增加，构件的承载力、延性、刚度等基本力学性能均发生不同程度的降低，构件的承载力在仅纵筋锈蚀的情况下降低较多，仅箍筋锈蚀的方式相对来说对构件的延性影响更大。在不同锈蚀方式的情况下，还考虑混凝土箍筋间距、配筋率、混凝土强度等级等不同子因素对构件力学性能影响，混凝土强度等级对构件承载力影响较大；在较小配筋率的情况下，纵筋的配筋率对于构件的承载力影响较小，但是构件峰值荷载所对应的位移随着配筋率的增大而减小，刚度增大。

以大量实验数据作为基础，选取了合适的本构模型进行承载力建模，对于未锈蚀构件以及完全锈蚀构件,通过理论分析推导建立承载力计算模型上限值、下限值。考虑不同锈蚀方式对承载力的影响程度，分仅纵筋锈蚀、仅箍筋锈蚀、纵筋箍筋均锈蚀三种锈蚀方式下建立承载力计算模型，通过大量试验数据拟合得到相关系数，并进行试验数据验证，模型建立较为精确。

关键词：钢筋锈蚀；混凝土柱；轴心受压；刚度；延性；承载力模型

ABSTRACT

Concrete structures have been invented as early as the Roman period and applied to large-scale construction projects. Nowadays, reinforced concrete construction technology is relatively mature in buildings, and various forms of structures are emerging, but as time goes by, the environmental media Corrosion, the durability problem of reinforced concrete gradually emerges, carbon in the atmospheric environment enters the concrete, causing carbonization of the concrete, generating micro-cracks, and water ingress, providing an environment for the electrochemical corrosion of the steel bar. And other destruction phenomena. Reinforced concrete columns use a reinforcing steel cage composed of longitudinal bars and stirrups as a skeleton. Compared with longitudinal bars, stirrups are closer to the edge of the section, the thickness of the concrete protective layer is smaller, and they are more susceptible to corrosion by the environment. As the main load-bearing member directly bears the box load, the corrosion of the longitudinal reinforcement has a serious impact on the bearing capacity of the corroded component. As a result, the cross-sectional area of ​​the concrete under load is reduced, and the corrosion of the stirrups weakens the restraint of the longitudinal reinforcement and the concrete in the core area. The lateral restraint is weakened, the members are more likely to deform, and the bearing capacity is reduced. In the actual project, due to the difference in the environment of the structure and its own structure, different corrosion methods are generated. For example, the outside of some structural columns is easily eroded by the rainwater environment, and the corrosion of only one longitudinal bar is easy to occur, and the thickness of some protective layers Larger structures only cause corrosion of the stirrups, but in practice most of the structures have corrosion of the longitudinal reinforcement of the stirrups.This paper collects data of different corroded reinforced concrete axial compression test. Through the summary drawing of the data, the analysis of the influence of different corrosion modes on the mechanical properties of concrete columns is conducted. The longitudinal and transverse data are compared to explore the concrete column mechanics under different corrosion modes. The law of performance change, at the same time, through theoretical analysis and actual data fitting, Establishing the bearing capacity formula of concrete columns provides a certain reference for the calculation and maintenance of bearing capacity of corroded components in actual engineering.

This paper collects nearly 70 domestic and foreign test papers on corroded reinforced concrete axial compression, using getdate data extraction software to collect the main test data, and plotting the processed normalized test data through origin to analyze the concrete column mechanics under different corrosion methods. According to the law of performance change, the following general conclusions are obtained: with the increase of the corrosion rate, the bearing capacity, ductility, and rigidity of the member are reduced to varying degrees. Compared with the stirrup-only corrosion member, only the longitudinal reinforcement corrosion method has a bearing capacity on the member The effect of rust is greater, and the method of corroding stirrups has a greater impact on the ductility of the member. In the case of different corrosion methods, the influence of different sub-factors such as concrete strength grade, reinforcement ratio, and stirrup spacing on the mechanical properties of the member is also considered. The bearing capacity is twice; under the condition of small reinforcement ratio, the reinforcement ratio of longitudinal reinforcement has little effect on the bearing capacity of the member, but the displacement corresponding to the peak load of the member decreases as the reinforcement ratio increases , The stiffness increases.

Based on a large amount of experimental data, a suitable constitutive model is selected for carrying capacity modeling. For uncorroded and fully corroded components, the upper limit and lower limit of the bearing capacity calculation model are derived through theoretical analysis. Considering the degree of influence of different corrosion methods on the bearing capacity, it is divided into three types of corrosion modes: longitudinal bar only corrosion, stirrup only corrosion, and longitudinal bar stirrer corrosion.For the bearing capacity model, correlation coefficients are obtained by fitting a large number of test data, and the test data is verified, and the model is more accurate.

Key words: corrosion of steel bars; concrete columns; axial compression; stiffness; ductility; bearing capacity mode

目录

第一章 前言 1

1.1 研究背景 1