反复荷载作用下锈蚀钢筋与混凝土粘结滑移研究

发布时间：2018-11-13 14:48

【摘要】：钢筋的锈蚀不仅使有效截面面积减少,而且会使其与混凝土的粘结性能发生退化。那些承受偶然荷载的结构，其锈蚀后仍需要抵御包括地震等荷载的作用，因此研究锈蚀钢筋混凝土在反复荷载作用下的粘结性能，建立锈蚀钢筋混凝土在反复荷载作用下的粘结滑移本构关系对正在服役结构的动力分析是相当重要的。本文从粘结性方面入手，研究不同钢筋类型和不同锈蚀率对混凝土与钢筋粘结性能的影响，探究了反复荷载下锈蚀钢筋混凝土的粘结机理，并对粘结滑移数据进行数值拟合。基于实验数据，建立了反复荷载下，锈蚀钢筋与混凝土的粘结滑移本构关系。本文主要研究工作如下： 1.在前期课题组单向加载锈蚀钢筋混凝土粘结性能试验研究的基础上，选用不同锈蚀率的光面钢筋和带肋钢筋制备同强度等级的混凝土中心拉拔试件，得到反复荷载作用下锈蚀钢筋与混凝土之间的粘结-滑移关系曲线，结果显示：在混凝土强度和钢筋直径相同的情况下，锈蚀率在2.16%~4.22%，混凝土与光面钢筋的极限粘结应力随着锈蚀率的增加有增大的趋势；当锈蚀率在4.22%~8.17%，其随着锈蚀率的增大而降低；锈蚀率在3.76%~12.85%，混凝土与带肋钢筋的极限粘结性能随着锈蚀率的增加逐渐降低，但带肋钢筋的粘结性能优于光圆钢筋的。反复荷载下，光圆钢筋的粘结性能退化最大的是试件出现极限粘结应力滑移后的循环中，，而带肋钢筋的粘结性能退化最大的发生在内凹与外凸变化的循环中。 2.在试验的基础上，对试验结果进行了分析，给出钢筋种类、试件锈蚀率对粘结强度的影响规律。采用数理统计方法拟合出粘结-滑移曲线，找出了能较好表述钢筋锈蚀程度与粘结应力的参数，分别建立了反复荷载作用下锈蚀光圆和带肋钢筋与混凝土的本构关系，为锈蚀钢筋混凝土构件或结构的受力分析提供基础数据和模型。
[Abstract]:The corrosion of steel bars not only reduces the effective cross-section area, but also degrades its bond performance with concrete. Those structures subjected to accidental loads still need to resist the effects of earthquake and other loads after corrosion, so the bond behavior of corroded reinforced concrete under repeated loads is studied. It is very important to establish the bond-slip constitutive relation of corroded reinforced concrete under repeated load for the dynamic analysis of the structure in service. In this paper, the effects of different types of steel bars and different corrosion rates on the bond properties of concrete and steel bar are studied, and the bonding mechanism of corroded reinforced concrete under repeated loading is discussed. The bond-slip data are fitted numerically. Based on the experimental data, the bond-slip constitutive relation of corroded steel bar and concrete under repeated load is established. The main work of this paper is as follows: 1. On the basis of the experimental study on the bond behavior of corroded reinforced concrete under unidirectional loading, the specimens with the same strength grade were prepared by using smooth steel bars with different corrosion rates and ribbed steel bars. The bond slip relation curve between corroded steel bar and concrete under repeated load is obtained. The results show that the corrosion rate is 2.16 and 4.22 when the strength and diameter of steel bar are the same. The ultimate bond stress between concrete and smooth steel bar increases with the increase of corrosion rate. When the corrosion rate is 4.222.17, the corrosion rate decreases with the increase of corrosion rate. The corrosion rate is 3.76 ~ 12.85. The ultimate bond property between concrete and ribbed steel bar decreases gradually with the increase of corrosion rate, but the bond property of ribbed steel bar is better than that of smooth circular steel bar. Under repeated loading, the bond behavior of smooth circular steel bar degenerates the most in the cycle after ultimate bond stress slip, while the bond behavior of ribbed steel bar degenerates most in the cycle of internal concave and convex variation. 2. On the basis of the experiment, the experimental results are analyzed, and the influence of the type of steel bar and the corrosion rate of the specimen on the bond strength is given. By using mathematical statistical method to fit the bond-slip curve, the parameters which can better describe the corrosion degree and bond stress of steel bar are found, and the constitutive relations between corroded smooth circular bar and ribbed steel bar and concrete under repeated load are established, respectively. Provide the basic data and model for the stress analysis of corroded reinforced concrete members or structures.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375

【参考文献】