受硫酸盐腐蚀的锈蚀型钢混凝土梁抗弯刚度研究

Study on the Bending Stiffness of Rusty Steel Reinforced Concrete Beams Corroded by Sulfate

型钢混凝土梁可能同时出现型钢锈蚀、混凝土受硫酸盐腐蚀的情况,为了研究此情况下的适用性问题,进行了四种不同情形(硫酸根离子浓度为0%、3%、6%、10%;型钢因锈蚀引起的失重率分别为0%、12%、28%、36%)下型钢混凝土梁受弯变形性能的试验研究。对各型钢混凝土梁进行了三分点处的集中加载,测得跨中挠度-荷载曲线与挠曲线,分析了延性性能的变化。结果表明,当混凝土受硫酸盐腐蚀及型钢锈蚀程度逐步加深时,跨中挠度-荷载曲线的非线性段逐步提前出现,梁的延性逐步增大,极限挠度值逐步降低,梁的抗弯刚度B_s也下降。进一步分析了出现这些规律的主要原因,并基于跨中挠度-荷载关系获得了梁短期抗弯刚度B_s的确定方法,可用于适用性中变形条件的验算。

In order to ensure the serviceability of steel reinforced concrete beam in the case of steel corrosion and sulfate corrosion,experimental study on flexural deformation performance of steel reinforced concrete beam has been carried out by considering four cases(sulfate ion concentration is 0%,3%,6%,and 10%;weight loss of steel due to corrosion 0%,12%,28%,36%).The steel reinforced concrete beams are concentratedly loaded at two points of trisection.Then the mid-span deflection-load curve and deflection curve are measured.The changes in ductility are analyzed.When the sulfate corrosion degree of concrete and section rusting degree of steel appear and deepen,main results include:non-linear phase of the mid-span deflection-load curve appears gradually in advance;the ductility of the beam gradually increases;the ultimate deflection value gradually decreases;and the value of bending stiffness B s gradually decreases.Furthermore,main reasons for the occurrence of these results are analyzed.Determine method of the beam short-term bending stiffness B s,which can be used to check the deformation conditions in serviceability,is also obtained based on the mid-span deflection-load relationship.