锈蚀钢筋混凝土梁节点抗震性能试验研究

【作者】 刘桂羽；

【导师】 罗小勇；

【作者基本信息】 中南大学 ， 土木工程， 2011， 硕士

【摘要】 钢筋混凝土结构由于疲劳荷载作用、环境锈蚀、材料老化引起的损伤积累,使得承载力和延性显著降低,进而导致了结构抗震性能显著降低。近年来,混凝土结构耐久性退化引起结构抗震性能变化的问题也越来越受到学术界的广泛关注。因此,对耐久性退化的钢筋混凝土结构抗震性能的研究具有主要理论意义。本文通过对不同钢筋锈蚀率的梁节点在低周反复荷载作用下的试验,研究钢筋锈蚀对混凝土结构抗震性能的影响。论文主要工作如下：1.通过进行试块的电化学加速锈蚀试验,确定电化学加速锈蚀试验试件与试块中钢筋锈蚀率的对应关系,为保证梁节点试件的电化学加速锈蚀试验的有效性提供了保证。2.进行了5个不同钢筋锈蚀率的梁节点在低周反复荷载作用下的试验。5个梁节点的钢筋锈蚀率分别为0%、3.19%、5.77%、9.12%、12.21%,实际锈蚀率与期望锈蚀率的最大偏差在试验允许误差范围内。3.通过对5个不同锈蚀率的梁节点在低周反复荷载作用下的试验,研究了钢筋锈蚀率对梁节点破坏形态、滞回性能、钢筋应变规律的影响。试验表明,梁节点的破坏以梁端塑性铰破坏为主,且随锈蚀率的提高其裂缝扩展更为迅速、裂缝宽度更宽；试件滞回曲线形状随锈蚀率的提高由未锈蚀时的丰满的梭形发展成为捏缩明显的反弓形甚至反S形状,滞回环所包围的面积逐渐减小,构件的耗能能力在逐渐降低；各试件荷载-应变滞回曲线加载阶段斜率随着锈蚀量的增加而减小,试件的刚度随锈蚀率的提高而在降低,且随着锈蚀量的增加,荷载应变曲线所包围的面积有减小的趋势,滞回环愈加不稳定。4.通过对梁节点的低周反复荷载试验,研究了钢筋锈蚀率对梁节点承载力和延性(含位移延性和滞回延性)的影响。试验表明,随着钢筋锈蚀量的增加,钢筋混凝土梁节点屈服荷载、极限荷载、位移延性系数、耗能能力均降低。进而根据试验数据提出了反映钢筋锈蚀率影响的梁构件承载力和延性计算方法和修正公式。计算公式能更好地反映结构在长期使用过程中对结构承载力和延性的退化。更多还原

【Abstract】 Reinforced concrete structures duing to fatigue loading, environmental corrosion, material damage caused by the accumulation of aging make the bearing capacity and ductility decreased significantly, which led to a significant reduction in seismic performance. In recent years, the durability of concrete structures seismic performance degradation of change is getting more attention by academia. Therefore, the study of seismic behavior of durability of reinforced concrete structures has the major theoretical significance.Based on the steel corrosion rate of the different nodes in the beam under cyclic loading test, we study the performance of steel corrosion on the seismic of concrete structures. Paper are as follows:1 By the electrochemical accelerated corrosion test block test to determine the electrochemical accelerated corrosion test specimens and test block in the corresponding relationship between steel corrosion rate, in order to ensure the beam joint specimen validity of the electrochemical accelerated corrosion tests to provide a guarantee.2 Carried out 5 different rates of steel corrosion in the low beam joints under cyclic loading test.5 beam joint of steel corrosion rates were 0%, 3.19%,5.77%,9.12%,12.21%, the actual rate of corrosion rate and the expected maximum deviation of rust tolerance in the test range.3 Through the corrosion rate of 5 different nodes in the beam under cyclic loading experiment to study the steel corrosion rate on the beam joint failure modes, hysteretic behavior, rules of steel strain. Tests showed that the destruction of the node beam plastic hinge damage to the main beam, and with the improvement of its corrosion crack propagation rate is more rapid, wider crack width; beam hysteretic shape of the curve with the corrosion rate of increase is not corroded by the time of plump spindle become apparent anti-pinch bow or even anti-S shape, surrounded by the hysteresis loop area decreases, the energy dissipation capacity of components decreased; each specimen load-strain hysteresis curve of the slope with the load phase the increase in the amount of corrosion decreases the stiffness of the specimen with the corrosion rate of increase in the lower, and with the increase in the amount of corrosion, surrounded by load-strain curve tends to decrease the area, hysteresis loop even more unstable.4 Beam node by cyclic loading tests of the steel corrosion rate of the bearing capacity and ductility of beam (including the displacement ductility and hysteretic ductility) of. Tests showed that with the increase in the amount of steel corrosion, reinforced concrete beam joint yield load, ultimate load, displacement ductility, energy dissipation capacity were reduced. According to the test data,put forward reflect the impact of steel corrosion rate of bearing capacity and ductility of beam calculation method and modified formula. Formula to better reflect the structure of long-term use in the different stages of the process of the structure of the bearing capacity and ductility changes.更多还原