STUDY OF BENDING BEHAVIOR OF REINFORCED CONCRETE BEAMS STRENGTHENED WITH NEAR-SURFACE-MOUNTED PRESTRESSED CFRP RODS
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摘要: 为研究表层嵌贴式预应力碳纤维复材(CFRP)筋加固钢筋混凝土梁的受弯性能,考虑CFRP筋初始预应力水平和纵筋配筋率等变化参数,完成了5根表层嵌贴式预应力CFRP筋加固梁以及1根对比梁的受弯试验。详细分析各变化参数对加固试件的承载性能、延性性能以及耗能能力等重要指标的影响,探讨了加固试件的受弯承载力计算方法。研究表明:加固试件多数为延性破坏,个别加固试件为剪切破坏;加固试件的极限承载力随着CFRP筋初始预应力水平的提高有所提升,最大升幅为98%,而加固试件的延性性能却有所降低;混凝土截面应变基本符合平截面假定。纵筋配筋率相同时,试件的耗能能力随CFRP筋初始预应力水平的增大而有所降低;初始预应力水平相同时,提升纵筋配筋率可在一定程度上提高试件的耗能能力。Abstract: To investigate the bending behavior of reinforced concrete beams reinforced with near-surface-mounted prestressed CFRP rods, a total 5 reinforced specimens and 1 unreinforced specimen were designed for bending test. Two parameters were considered in the test, the inital prestressed level of CFRP rods and longitudinal steel ratio. Three important properties, such as bearing capacity, ductility and energy dissipation capacity of CFRP rods were analyzed in detail and the calculation method of flexural bearing capacity of reinforced specimens was discussed. The results showed that the failure modes of reinforced specimens were mostly ductile failure, and some specimens were brittle failure. With the increase of the initial prestress level of CFRP rods, the ultimate bearing capacity of strengthened specimens increased and the maximum increase was 98%, but the ductility of strengthened specimens was reduced. The main strain of reinforced specimen could conform to stress plain section assumption. With the same longitudinal reinforcement ratio, the energy dissipation capacity of the specimens decreased with the increase of the initial prestress level of the CFRP rods; when the initial prestress level was the same, increasing the longitudinal reinforcement ratio could improve the energy dissipation capacity of the specimens to a certain extent.
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