受到外围约束的混凝土板会在内部产生拱效应,为了研究其中玻璃纤维增强复合材料(GFRP)筋的作用,对10块板带进行了破坏性试验,发现:板带开裂后拱效应逐渐明显,受拉区GFRP筋的作用相当于拱脚间的弹簧,筋材等效弹簧刚度增加,拱效应减弱;反之,拱效应增强.筋材配置过少或配置在板厚中间均不利于挠度和裂缝宽度控制,配筋适当时GFRP筋与拱效应共同作用,可以缩小适筋板带与超筋板带之间正常使用性能的差距,配筋情况决定裂缝分布及板带破坏模式,对极限承载力影响较小.此外,文中还对GFRP筋的作用进行了量化分析,考虑了拱效应的设计方法所预测的筋材应变比规范计算值更接近试验结果.
Due to the restraint from the components aside concrete slabs, arching action occurs in these slabs. In order to reveal the influences of glass fibre reinforced polymer (GFRP) bars on the concrete slabs, ten slabs were loaded until failure. The results show that the arching action gradually become significant after the occurrence of cracking in the slabs, and that, the role of GFRP bars in the tensile area is like that of the springs connecting with two arch legs, that is, with the increase of the stiffness of the equivalent springs for reinforcement, the arching action weakens, otherwise the arching action is enhanced. Furthermore, it is found that too low reinforcement percentage in the slabs or locating reinforcement at the mid-depth of the slabs is unprofitable to the control of both the deflection and the cracking width, while appropriate reinforcement percentage makes the GFPR bars and the arching action jointly play their roles, which can narrow the gap in the serviceability between the slab with an appropriate reinforcement percentage and that with a higher reinforcement percentage, and that the cracking distribution and failure mode of the slab depend on its reinforcement configuration, while the reinforcement configuration has a relatively slight influence on the ultimate bearing capacity. In addition, the role of GFRP bars is quantified, and the results obtained through the design method considering the arching action are more accordant with the experimental results than the calculated values based on current design standards are.