预应力CFRP绞线和钢筋混合配筋混凝土梁的抗弯性能

为了探索碳纤维复材(CFRP)绞线在混凝土结构中的应用,采用CFRP绞线作为预应力筋,开展了预应力CFRP绞线和钢筋混合配筋混凝土梁的抗弯性能试验研究。试验结果表明:平截面假定适用于混合配筋的混凝土梁；配置预应力CFRP绞线可以显著提高混凝土梁的抗弯承载力,相比于普通钢筋混凝土梁,混合配筋混凝土梁的开裂荷载、屈服荷载和极限荷载分别提高了74%~146%、27%~48%和29%~50%,但混合配筋混凝土梁的延性明显降低；在混凝土压碎失效模式下,预应力水平和预应力CFRP绞线数量对延性影响并不明显；GB 50608—2020《纤维增强复合材料工程应用技术标准》中预应力纤维复材(FRP)筋混凝土梁的抗弯承载力计算公式可以应用于预应力CFRP绞线和钢筋混合配筋混凝土梁的抗弯承载力计算。

Flexural behavior of concrete beams reinforced by hybrid prestressed CFRP strands and steel rebars

To explore the application of the carbon fiber reinforced polymer (CFRP) strands in concrete structures, the CFRP strands were used as the prestressed reinforcements in this study. The experimental study on the flexural behavior of concrete beams reinforced by hybrid prestressed CFRP strands and steel rebars was conducted. The test results indicate that the plane cross-section assumption is suitable for the hybrid reinforced concrete beams. Application of the prestressed CFRP strands can significantly increase the flexural capacity of concrete beams. The cracking, yielding, and ultimate loads of the hybrid reinforced beams are increased by 74%-146%, 27%-48% and 29%-50%, compared with ordinary reinforced concrete beams. However, the ductility of the hybrid reinforced beams is obviously reduced, while the prestress level and number of prestressed CFRP strands have an insignificantly effect on the ductility under the failure mode of concrete compressive crushing. The calculation equations of the flexural capacity for prestressed fiber reinforced polymer (FRP) bar reinforced concrete beams in GB 50608-2020 Technical Standard for Fiber Reinforced Polymer in Construction can be used for calculating the flexural capacity of the concrete beams reinforced by hybrid prestressed CFRP strands and steel rebars.