基于多因素耦合老化模型的FRP防腐加固混凝土桥墩方法研究

发布时间：2018-06-30 00:50

本文选题：防腐加固设计 + 单因素老化模型　；参考：《西南科技大学》2015年硕士论文

【摘要】：随着我国经济的增长,桥梁建设快速发展,桥墩(本文皆指钢筋混凝土桥墩)的耐久性问题越来越引起人们的重视。对桥墩的防腐加固研究已刻不容缓。纤维增强复合材料(Fiber Reinforced Polymer或Fiber Reinforced Plastic简称为FRP)不仅因其有较好的结构性能,而且具有良好的耐久性能。基于FRP良好的耐久性能,提出一种防腐加固桥墩的耐久性设计方法具有重要意义。参阅国内外大量文献,归纳总结了影响混凝土、钢筋及FRP耐久性的主要因素及老化规律。建立了混凝土、钢筋及FRP的单因素抛物线-直线老化模型。基于试验数据得到的单因素模型与实际自然环境中的有很大不同,将我国环境以不同因素的影响程度进行区划,找出各分区中该因素对混凝土、钢筋及FRP影响程度与试验中的不同,对单因素老化模型进行修正,建立单因素修正老化模型。混凝土、钢筋及FRP的老化是由多种因素造成的,单因素修正老化模型不能够表征其实际的老化趋势。考虑影响混凝土、钢筋及FRP老化的主要因素及所占的权重,建立最终的多因素耦合老化模型。确定FRP防腐加固混凝土桥墩的耐久性极限状态,建立基于耐久性抗力和环境作用效应的极限状态方程,基于工程目标使用期和得到的多因素耦合老化模型,通过反演的方法得到环境作用效应。以耐久性试验的方法,得到FRP拉伸强度与截面有效厚度的关系,求得FRP的耐久性抗力,通过极限状态方程求得FRP的加固量。与其他的FRP耐久性老化模型相比,抛物线-直线模型是以非线性的方式表达耐久性指标的衰减趋势,计算值和实测值误差较小。模型参数只有2个,且易求得。将耦合老化模型与自然环境下FRP的老化趋势进行分析比较,发现下降趋势基本与模型曲线一致,模型曲线基本可以表达FRP自然环境下的耐久性能的变化趋势。对加固设计方法研究有较好的指导作用,有利于提高加固设计的可靠性。
[Abstract]:With the economic growth and the rapid development of bridge construction, people pay more and more attention to the durability of pier (reinforced concrete pier). It is urgent to study the anticorrosion and reinforcement of bridge piers. Fiber reinforced Polymer or Fiber reinforced plastic (FRP) not only has good structural properties, but also has good durability. Based on the good durability of FRP, it is of great significance to put forward a durability design method for anti-corrosion and reinforcement of bridge piers. The main factors affecting the durability of concrete, steel bar and FRP are summarized by referring to a large number of literatures at home and abroad. The single factor parabola linear aging model of concrete, steel bar and FRP is established. The single factor model based on the test data is very different from the actual natural environment. The environment of our country is zoned according to the influence degree of different factors to find out the effect of this factor on concrete. The influence degree of steel bar and FRP is different from that in test. The single factor aging model is modified and the single factor modified aging model is established. The aging of concrete, steel bar and FRP is caused by many factors. The single factor modified aging model can not express the aging trend of concrete, steel bar and FRP. Considering the main factors affecting the aging of concrete, steel bar and FRP and their weight, the final multi-factor coupled aging model is established. The durability limit state of concrete pier strengthened with FRP is determined, the limit state equation based on durability resistance and environmental effect is established, and the multi-factor coupling aging model is obtained based on the project target life and the multi-factor coupling aging model. The environmental effect is obtained by inversion method. The relationship between the tensile strength of FRP and the effective thickness of section is obtained by the method of durability test, and the durability resistance of FRP is obtained, and the strengthening capacity of FRP is obtained by the limit state equation. Compared with other FRP durability aging models, the parabola linear model represents the attenuation trend of the durability index in a nonlinear manner, and the error between the calculated values and the measured values is smaller. There are only two parameters of the model, and it is easy to get. The aging trend of coupled aging model is compared with that of FRP in natural environment. It is found that the decreasing trend is basically consistent with the model curve, and the model curve can basically express the change trend of durability under natural environment of FRP. It is helpful to improve the reliability of reinforcement design.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.72

【参考文献】