中文摘要：

通过13根钢筋混凝土试验梁的加速锈蚀试验与疲劳加载试验,研究了锈蚀钢筋混凝土梁在疲劳反复荷载作用下的破坏形态及刚度变化.试验结果表明：所有锈蚀后的试验梁在循环加载到一定次数后,均发生以某一根主筋疲劳断裂为标志的疲劳破坏;未锈蚀的试验梁在循环加载200万次后不发生疲劳破坏,并且疲劳作用对未锈蚀梁的静力破坏形态及极限承载能力没有实质影响.分析了疲劳作用下锈蚀钢筋混凝土梁刚度的变化规律,发现其存在明显的两阶段特征,即缓慢减小并趋于稳定.根据试验实测数据,引入分别考虑钢筋锈蚀与疲劳作用的刚度修正系数,定量化地提出了疲劳加载下锈蚀钢筋混凝土梁刚度的修正计算公式,并对公式计算值与试验实测值进行了对比验证.该公式可用于锈蚀钢筋混凝土梁桥在长期活载作用下挠度变形的计算与评估.

英文摘要：

Based on the accelerated corrosion test and the fatigue loading test of thirteen reinforced concrete beam specimens, the failure mode and flexural stiffness of corroded reinforced concrete （ RC） beams under fatigue loads are investigated.The test results show that, after cyclic loading a certain number of times, fatigue failure occurs in all the corroded beam specimens and it is marked by the fatigue fracture of a main reinforcing bar, and that, nofa-tigue failure occurs in uncorroded specimens after cyclic loading two million times, and the fatigue effect has no substantial influence on the static failure mode and the ultimate bearing capacity of uncorroded RC beams.More-over, analysis on the flexural stiffness change of corroded RC beams under the effect of the fatigue loading indicates that there are two obvious stages, specifically, the flexural stiffness decreases slowly and then tends to be stable. According to the measured data, the stiffness correction coefficients, which take into account the steel bar corrosion and the fatigue effect respectively, are introduced to quantitatively derive the correction formula calculating the flexural stiffness of the corroded RC beams under the fatigue loading, and the formula is then verified by comparing the calculated values with the measured ones.It is also found that the proposed formula can be used to calculate and evaluate the deflection of corroded RC girder bridges under long-term live loads.