GFRP筋混凝土板正截面抗弯承载力研究

RESEARCH ON THE FLEXURAL BEHAVIOR OF CONCRETE SLABS WITH HYBRID REINFORCEMENT OF GFRP BARS

为了研究GFRP筋混凝土板的正截面抗弯承载力,基于平截面假定、内力平衡条件以及变形协调条件,对GFRP筋混凝土板在适筋及适量超筋两种配筋设计情形下的正截面抗弯承载力计算公式进行了推导,通过8组具有不同配筋率与混凝土强度等级的GFRP筋混凝土板抗弯承载力试验,对推导的计算公式进行了验证,同时研究了构件抗弯承载力与配筋率、混凝土强度等级之间的变化关系。结果表明:试验得到的极限承载力与公式计算的理论承载力数据吻合较好,可以较准确地反映GFRP筋混凝土板抗弯承载力的计算过程;适量超筋设计构件破坏形式表现为以受压区混凝土被压碎为标志的塑性破坏,这种设计方式更有利于提高GFRP筋混凝土板的安全性能;同时为了保证混凝土板达到极限承载力时受拉区GFRP筋不被拉断,建议设计配筋率取1.4倍的平衡配筋率;随着GFRP筋混凝土板配筋率的增加,构件承载力系数逐渐增大,安全储备也逐渐提高;GFRP筋混凝土板的抗弯承载力随着配筋率与混凝土强度的增加而逐渐增大。

In order to study the flexural behavior of concrete slabs with GFRP bars,based on the the assumption of plane section,condition of internal force and deformation compatibility condition,the calculation formula of flexural capacity of GFRP reinforced concrete slabs under the two design cases of under-reinforced and proper amount of extra-reinforced is deduced. By the 8 groups of tests of GFRP slabs with different reinforcement ratio and concrete strength grade of concrete,the calculation formula of flexural capacity is verified. At the same time,the law between the variation of flexural capacity and reinforcement ratio,concrete strength is studied. The results show that the ultimate bearing capacity obtained by the experiment is in good agreement with the theoretical bearing capacity calculated by the formula,which can accurately reflect the calculation process of flexural strength of GFRP concrete slab. The failure mode of the design elements of the right amount of super reinforced concrete is destroyed by the crushing of concrete,which is more conducive to improving the safety performance of GFRP reinforced concrete slabs. At the same time,in order to ensure that the GFRP bar is not broken before the flexural capacity of concrete slab reach the maximum,it is proposing that the ratio of the balanced reinforcement ratio is of 1.4 times of the reinforcement ratio. With the increase of reinforcement ratio of GFRP reinforced concrete slab,the flexural capacity increases gradually,security reserves are also gradually increased. The flexural bearing capacity of GFRP reinforced concrete slab increases with the ratio of reinforcement ratio and concrete strength.