CFRP预应力筋混凝土梁在重复荷载作用下的受力性能

碳纤维增强聚合物(CFRP)筋的线弹性力学性能使采用CFRP配筋的混凝土结构延性较差,因而CFRP配筋混凝土结构的延性已成为其应用中最受关注的问题之一。通过对纤维增强聚合物(FRP)配筋混凝土结构延性指标的回顾,本文基于能量耗散的观点引入了反映FRP配筋混凝土梁延性特性的延性指标,并提出了梁荷载-挠度曲线下降段的修正公式,通过试验验证了其可靠性。在此基础上对T梁的延性进行了参数分析。分析结果表明:翼缘宽度对提高梁的延性和极限变形的有效性要大于预应力筋无粘结长度对提高梁的延性和极限变形的有效性。

Behaviors of Concrete T-beams Prestressed with CFRP Tendons under Cyclic Loading

As the concrete members prestressed with CFRP(Carbon Fiber Reinforced Polymer/Plastics) tendons are lack of ductility due to the linear elastic behavior of CFRP tendons up to failure,the ductility of structure prestressed with CFRP becomes a main concern.Following a review of ductility index applied to concrete members prestressed with CFRP tendons,the ductility index based on the energy concept is introduced,and a revised formula evaluating the unloading phase of the load-deformation curve is presented,with reasonable agreement between predicted values and tested values being obtained.A parametric study of ductility of T beams has been conducted.It is illustrated that of the two factors,the ductility and the ultimate deformation,which both contribute to the improvement of the flange width and unbonded length,the former is more effective.