“锈蚀-加固-锈蚀”RC梁力学行为及承载力试验

发布时间：2018-05-11 22:25

本文选题：桥梁工程 + 锈蚀钢筋混凝土梁　；参考：《中国公路学报》2016年09期

【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。
[Abstract]:In order to study the mechanical properties of corroded reinforced concrete beams strengthened with steel plates and after secondary corrosion, By designing 9 test beams (concrete strength grade C25, tensile steel bar diameter 22 mm), and dividing the specimens into three groups according to the thickness of the protective layer, each group consists of one corroded beam, one corroded strengthening beam and one corroded reinforcement recorroded beam, The design corrosion rate of corroded beams and corroded strengthened beams is 10, and the design corrosion rate of corroded rerusted beams is 15. The strain, deflection, crack development, failure mode and bearing capacity of the specimen beam are analyzed by single point loading. The experimental results show that the strain of the mid-span section of the corroded beam and the corroded strengthened beam basically accords with the assumption of the plane section, but the corrosion strengthened recorroded beam does not accord with this assumption in general. At the same time, the essence of steel plate to increase the bearing capacity of members is to increase the height of the section under compression; the deflection of the corroded beam changes after the yield of the steel bar, while the corroded strengthening beam and the corroded beam can bear part of the load. The deflection varies slowly with the load, the corroded beam is damaged by the appropriate reinforcement beam when the corrosion rate is low, while the corroded strengthened beam and the corroded reinforced corroded beam are both subjected to diagonal tensile failure, and the corrosion of the tensile steel bar and the deterioration of concrete, the corrosion of the corroded steel bar and the deterioration of the concrete, The ultimate bearing capacity of the partially corroded strengthened beams is lower than that of the corroded beams, and the reinforcement effect of the steel plate is completely offset. When the thickness of the protective layer and the steel plate is the same, the greater the uneven corrosion of the main reinforcement, the smaller the ultimate bearing capacity of the beam. When the corrosion of the main tendons is more balanced, the ultimate bearing capacity decreases by 10 ~ 15kN for each increase of the secondary corrosion rate.
【作者单位】：长沙理工大学省部共建桥梁工程安全控制教育部重点实验室;
【基金】：国家重点基础研究发展计划(“九七三”计划)项目(2015CB057701,2015CB057706) 国家自然科学基金项目(51178060,51378061) 交通运输部主干学科应用基础研究项目(2014319825160) 湖南省教育厅优秀青年项目(15B015) 湖南省土木工程优势特色学科创新基金项目(201515)
【分类号】：TU375.1

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