锈蚀RC桥梁弯曲抗力时变概率模型与试验研究

PROBABILISTIC RESISTANCE MODEL AND EXPERIMENTAL INVESTIGATION FOR CORRODED RC BRIDGES

在退化RC结构的时变性能评估、剩余寿命预测以及维修加固决策分析中,其抗力模型的建立至关重要。钢筋锈蚀导致钢筋的屈服强度降低、改变钢筋力学行为和影响钢筋与混凝土之间的粘结行为。钢筋腐蚀损失量影响钢筋的失效模式,即从延性破坏到脆性破坏变化。该文发展了退化RC桥梁的概率抗力时变模型,可以定量考虑腐蚀对钢筋力学行为、倒塌机理和粘结性能的影响。建立退化结构的抗力概率模型可以抓住退化结构的退化机理、点蚀分布、结构尺寸参数、粘结行为、腐蚀扩展、钢筋失效模式和计算模型的随机性和变异性。RC梁的加速腐蚀试验和旧桥的破坏性试验验证了该文模型的正确性和可靠性。

It is known that it is very important to build a time-variant probabilistic resistance model for assessing a time-dependent performance, predicting remaining life and optimizing repair strategy for deteriorated RC bridges. Corrosion of steel rebar results in reducing its yield strength, changing the mechanical behavior of corroded reinforcing bars and affecting the bond behavior between concrete and reinforcing bars. The amount of corrosion loss of corroded reinforcing bars affects the failure mode of corroded steel bars. That is to say, the failure mode varies from ductile to fracture. This paper develops a probabilistic resistance model that quantitatively considers the influences of corrosion on the mechanical behavior, collapse mechanism and bond behavior of corroded reinforcing bars. The developed resistance model can capture the random and variability of deterioration mechanism, pitting corrosion distribution, geometrical sizes, corrosion propagation, failure modes and the calculation model of deteriorated RC structures. The accelerated corrosion test of RC structures and destructive testing of existing RC bridges demonstrated the correctness and reliability of the develoned model.