新型混杂BFRP和SFCB配筋梁的裂缝宽度分析

Analysis of crack width of new hybrid reinforced beams with BFRP and SFCB

针对采用玄武岩纤维增强复合材料(Basalt fiber-reinforced polymer,BFRP)筋和钢连续纤维复合筋(steel-FRP composite bar,SFCB)制备的新型纤维复合材料和钢筋组合的混杂配筋(hybrid reinforced concrete,Hybrid-RC)梁多采用非对称配筋,可能导致结构产生的裂缝宽度过大的问题,设计7根混凝土梁,研究了非对称配筋形式下Hybrid-RC梁的裂缝.试验结果表明:等效配筋率ρe及钢筋和FRP筋之间的轴向拉伸强度比γ会对Hybrid-RC梁的裂缝宽度产生较大影响;分别给出美国混凝土协会(ACI)规范和加拿大规范(CSA)计算Hybrid-RC梁裂缝宽度时粘结系数kb的建议值.

The hybrid reinforced concrete(Hybrid-RC)beams with the combination of new fiber composite materials and steel bars of BFRP(Basalt fiber-reinforced polymer)and SFCB(steel-FRP composite bar)are often reinforced with asymmetric reinforcement,which may leads to excessive crack width in the structure.To solve the problem,seven concrete beams were designed.The crack behavior of Hybrid-RC beam with asymmetric reinforcement was investigated.The experimental results show that the equivalent reinforcement ratio ofρe and the axial tensile strength ratio ofγbetween reinforcement and FRP bars have great influence on the crack width of Hybrid-RC beam.For the calculation of the crack width of Hybrid-RC beams,the recommended values of the bond-quality coefficient of kb using the American Concrete Institute(ACI)code and the Canadian Standard Association(CSA)code are given respectively.