普通大气环境下混凝土桥梁时变抗弯性能

Time-Variant Flexural Performance Analysis of Concrete Bridges in Atmospheric Environment

目的研究混凝土桥梁在碳化、钢筋锈蚀等环境因素影响下的时变抗弯性能,促进全寿命设计方法在桥梁设计实践中的应用.方法通过实验研究结构受力状态对混凝土碳化的影响,根据已有研究成果分析钢筋锈蚀、钢筋强度退化、粘结强度退化等影响因素,并进一步对混凝土保护层锈胀剥落破坏进行数值仿真研究,在此基础上提出普通大气环境下混凝土桥梁时变抗弯性能的分析方法.结果利用提出的分析方法对实桥进行了计算分析,结果表明在各种退化因素影响下,桥梁的性能逐年退化,预应力钢筋开始锈蚀后,退化速率明显加快.结论各种退化因素对桥梁性能的影响不容忽视,在桥梁的设计实践中引入时变性能分析更为科学合理.

In this paper,the time varying flexural performance of concrete bridges under the influence of environmental factors such as carbonation and steel corrosion was studied,in order to promote the application of whole life design method in bridge design. Firstly,the effect of structural stress on concrete carbonization was studied experimentally. And then,the corrosion of steel reinforcement,strength degradation and degradation of bond strength were analyzed by the existing literature.Furthermore,the concrete cover corrosion spalling damage was investigated by numerical simulation.In the end,the time-variant flexural performance analysis method of concrete bridges in atmosphere environment was suggested and an actual bridge was analyzed by this method. The results demonstrated that the performance of the bridge degraded gradually and the degradation rate accelerated obviously after the initial corrosion of the pre-stressed reinforcement. The influence of degradation should not be ignored in the design,and the time varying performance should be considered.