论文部分内容阅读
针对采用超声波CT无损检测技术对钢筋混凝土梁构件进行检测时可能导致误诊这一问题,借助混凝土梁试件在上限0.7Pu、下限0.1Pu的重复加载物理试验和超声波CT无损检测技术,通过观察卸除重复荷载后试件钢筋、混凝土的应变和超声波速的变化,展开对重复荷载作用后试件钢筋及混凝土应变、超声波速与卸载时间试验关系的研究,定义应变恢复速率νε和超声波速恢复率ηVP两个物理量来表征试件的损伤恢复情况。结果表明,νε主要受外荷载影响并随外荷载变化而变化,对试件损伤恢复的贡献可以基本忽略;ηVP主要受试件裂缝影响,随着卸载时间的增加,试件宏观开裂和微裂缝逐渐闭合,ηVP值也逐渐增大。这为桥梁的健康诊断及寿命预测提供了一定的依据和支持。
When using ultrasonic CT non-destructive testing technology to detect reinforced concrete beam components may lead to misdiagnosis of this problem, with the concrete beam specimens in the upper limit of 0.7Pu, the lower limit of 0.1Pu repeat loading physics and ultrasonic CT nondestructive testing technology through the observation and disassembly In addition to the repeated load after the specimen steel, concrete strain and ultrasonic velocity changes, expand the repeated load on the specimen steel and concrete strain, ultrasonic velocity and unloading time test study defines the strain recovery rate ν ε and ultrasonic recovery rate ηVP two physical quantities to characterize the damage recovery of the specimen. The results show that νε is mainly affected by the external load and changes with the change of the external load. The contribution of ηVP to the damage recovery can be neglected. The main impact of ηVP is the crack of the specimen. With the increase of unloading time, the macroscopic and micro-cracks Gradually closed, ηVP value also gradually increased. This provides some basis and support for the bridge’s health diagnosis and life prediction.