中文摘要：

为了研究锈蚀钢筋混凝土梁采用钢板加固后以及加固后二次锈蚀时的力学性能,通过设计9片试验梁（混凝土强度等级为C25,受拉钢筋的直径为22mm）,并将试件按照保护层厚度（25,30,35mm）分成3组,每组包括1片锈蚀梁、1片锈蚀加固梁和1片锈蚀加固再锈蚀梁,其中锈蚀梁和锈蚀加固梁的设计锈蚀率为10%,锈蚀加固再锈蚀梁的设计锈蚀率为15%。通过对试件梁进行单点加载的方式,分析了试件梁的跨中截面应变、挠度、裂缝开展规律、破坏模式和承载力状况。试验研究表明：锈蚀梁和锈蚀加固梁的跨中截面应变基本符合平截面假定,而锈蚀加固再锈蚀梁总体上不再符合此假定,同时钢板提高构件承载力的本质是增加截面的受压区高度;锈蚀梁在钢筋屈服后挠度出现突变,而锈蚀加固梁和锈蚀加固再锈蚀梁由于钢板能够承担部分荷载,挠度随荷载变化较为平缓;锈蚀梁在锈蚀率较小时表现为适筋梁破坏,而锈蚀加固梁和锈蚀加固再锈蚀梁均表现为斜拉破坏;受拉钢筋的锈蚀和混凝土的劣化,使得部分锈蚀加固梁二次锈蚀后的极限承载力比锈蚀梁低,钢板的加固效果完全被抵消;在保护层和钢板厚度相同时,当主筋锈蚀的不均衡性越大,梁的极限承载力越小,当主筋锈蚀较均衡时,二次锈蚀率每增加1%,极限承载力下降10~15kN。

英文摘要：

In order to investigate the mechanical behavior of corroded RC beams strengthened with bolted steel plates and those beams experienced secondary corrosion,nine pieces of test beams were designed,among which strength grade of concrete is C25 and the diameter of the steel bar is22 mm.These beams were divided into three groups according to the thickness of concrete cover which were 25 mm,30 mm and 35 mm,and each group consisted of one piece of corroded RC beam,one piece of corroded RC beam strengthened with bolted steel plates and one piece of strengthened beams experienced secondary corrosion.The corroded beam and the corroded beams strengthened by steel plates were designed with the corrosion rate of 10% and the corrosion ratewas 15% for strengthened beams experienced secondary corrosion.Through the single point loading method,the strain,deflection,crack development law,failure mode and bearing capacity of the mid-span cross section of the specimen were analyzed.The results show that the strains of the corroded beam and the strengthened beams at middle-span cross section are in good agreement with the plain section assumption basically,while that of the beams of secondary corrosion is generally not in agreement with the assumption.At the same time,the essence of the risen bearing capacity by steel plate is to increase the height of the compression zone of the section.The deflection of corroded beams changes suddenly when steel bar yields,the deflection variations of specimen strengthened with bolted steel plates and specimen experienced secondary corrosion are gentle because the plates can bear part of the load.Corroded beams perform as suitable reinforcement beam damage when corrosion ratio is small,and the specimen strengthened with bolted steel plates and the specimen experienced secondary corrosion perform as a diagonal tension failure.Due to the deterioration of corrosion and concrete,the ultimate bearing capacity of the strengthened beams experienced secondary corrosion is lower than that of the corroded bea