预应力CFRP筋混凝土板试验研究

Experimental Study on Prestressed CFRP Reinforced Concrete Slab

设计了一种以CFRP筋用作预应力筋的新型板结构,对预应力CFRP筋混凝土板实现过程中的关键性问题—CFRP筋锚固系统进行了试验研究,并对预应力CFRP筋混凝土板进行室内抗弯性能试验,系统地分析了预应力CFRP筋混凝土板的开裂荷载、极限荷载、CFRP筋应力状态和破坏形态等,结果表明:受拉区配有普通钢筋的无粘结预应力CFRP筋混凝土板的抗弯受力过程大致可分成3个阶段:加载初期的弹性受力阶段,裂缝出现至拉区普通钢筋屈服的弹塑性阶段,CFRP筋主要承拉的变形快速发展破坏阶段;无粘结预应力CFRP筋混凝土板的破坏形式为CFRP筋的低模量导致的变形快速发展,裂缝延伸,有效受压混凝土面积减小导致的混凝土压碎失效;裂缝形态多为等间距的平行裂缝,裂缝初期发展较慢,在普通钢筋屈服后迅速开展。

A new type of bridge deck structure whose prestressed tendons are CFRP tendons is designed. The key problem,i. e.,the experiment research on the anchoring system of CFRP,is conducted in the process of making prestressed CFRP reinforced concrete slab, the indoor flexural performance test of prestressed concrete slabs with CFRP prestressed tendons are carried out. The cracking load and ultimate load of such slab,the stress state and failure morphology of CFRP tendons,etc. are analyzed systematically. The result shows that（ 1） the bending resistance process of unbonded prestressed CFRP tendon slab with ordinary steel bars in the tension zone can be divided into 3 stages： the initial elastic loading stage,the elastic-plastic stage from cracks appearance to ordinary steel yielding,the stage of rapid deformation development and failure when CFRP tendons mainly bear tension;（ 2） the failure modes of unbonded prestressed CFRP tendon slab are the rapid development of deformation due to the low modulus of CFRP tendons,the extension of cracks,and the crushing failure of concrete due to the decrease of the area of effective compressive concrete;（ 3） the fractures are mostly equidistant Parallel cracks,the cracks develop slowly in the early stage,but develop quickly after the ordinary steel yielding.