中文摘要：

结合48片钢筋混凝土梁的抗弯试验数据,探讨了不同锈蚀率的钢筋混凝土矩形梁极限抗弯承载力的变化规律,对平截面假定进行了验证,并给出了在平截面假定不成立的前提下,受弯梁处于极限状态时跨中截面处钢筋应变和钢筋对应处混凝土应变的关系。通过构造新的几何条件给出了光圆钢筋和螺纹钢筋混凝土矩形梁受压区高度随锈蚀率变化的计算公式,进而推导出锈蚀钢筋混凝土正截面抗弯承载力计算公式,并通过试验数据进行验证。结果表明：钢筋锈蚀状态下,钢筋和混凝土的应变不再符合平截面假定;提出的抗弯承载力计算公式计算结果准确可靠,可用于指导工程实践。

英文摘要：

Based on the experimental data of 48 corroded reinforced concrete （RC） beams, the laws of the flexural capacity of the reinforced concrete rectangular beams with different corrosion ratios were studied, the assumption of plane cross-section was verified and the relation between the strain of steel bar and the strain of the concrete corresponding to the steel bar in the ultimate state of the beams was gained when the assumption of plane cross-section no longer came into existence. Through the constructed geometrical condition, the formula of the compressive region height corresponding with different corrosion ratios of the RC rectangular beams with plain steel bar and twisted steel bar was given. Then, calculation formula of normal section flexural capacity of corroded reinforced concrete was deduced and it was verified by the experimental data. Test results show that strains of steel bar and concrete no longer conform with the assumption of plane cross section under corroded state of steel bar. Results calculated by proposed flexural capacity formula are accurate and reliable. The calculation method of flexural capacity can be used to guide engineering practice.