铁路梁桥在多因素腐蚀环境影响下构件抗弯性能研究

为了研究西格铁路专用线中桥梁结构在多种因素腐蚀环境影响下抗弯性能的变化,分别分析水分、二氧化碳浓度以及氯离子等因素对钢筋抗拉强度、有效受拉面积、混凝土碳化以及两者之间的黏结强度等性能方面的影响,基于钢筋锈蚀之后与混凝土之间重新形成的协同工作关系,通过构造新的几何条件,对锈蚀钢筋混凝土构件抗弯承载力的计算公式重新进行推导,分析钢筋锈蚀程度对构件抗弯性能的影响。研究表明:钢筋混凝土构件在腐蚀环境长期作用下,钢筋的抗拉强度不断降低,有效受拉面积不断减小,混凝土碳化现象加剧,两者之间的黏结性能削弱;通过重新构造锈蚀钢筋与混凝土之间应变关系,推导得到的锈蚀钢筋混凝土构件抗弯承载力计算公式可以较好地反映试验结果;随着钢筋锈蚀程度的不断增加,构件抗弯承载力损失率也在不断提高,当锈蚀率达到17%时,构件承载力损失率可达到30.33%。

Research on Flexural Performance of Railway Beam Bridge under Multi Factor Corrosion Environment

In order to understand the effects of various corrosive factors on the bending behavior of bridge structures in Xi-Ge railway special line,this article analyzes respectively the influences of water,carbon dioxide concentration and chlorine ion on tensile strength,effective tensile area,concrete carbonization and the bond strength between two kinds of concrete. Based on the cooperative relationship between the corroded reinforcement and the concrete,the formula for calculating the flexural capacity of the corroded reinforced concrete members is derived by constructing new geometrical condition,and the influence of corrosion degree of the reinforcement on the flexural performance of structures is analyzed. The study results show that reinforced concrete members under long time corrosive environment tends to reduce the tensile strength of the reinforcement continuously,the effective tensile area decreases continuously,the concrete carbonation intensifies and the bonding property is reduced. By constructing the strain relationship between the corroded reinforcement and the concrete,the formula for calculating flexural capacity of corroded reinforced concrete members can better reflect the calculation characteristics of structures. With the increase of corrosion degree of reinforcement,the loss rate of flexural bearing capacity of component is also increasing. When the corrosion rate reaches 17%,the lost of flexural capacity of the component comes up to 30. 33%.