FRP筋混凝土板裂缝宽度的计算方法

摘要

Based on the calculation formula of crack width of FRP(Fiber Reinforced Plastic) reinforced concrete beam,the calculation method of slab was studied and the influence mechanism of the difference between the slab and beam structure was discussed in this paper.The modification method of the parameters such as the average crack spacing,the section internal force arm coefficient and the FRP bar strain non-uniformity coefficient were introduced and the proposal to abolish the lower limit of the effective reinforcement ratio was suggested.The crack width of FRP reinforced concrete slab under different effective reinforcement ratios and tensile stress were calculated by using the proposed method.The results show that when the effective reinforcement ratio is less than 0.01,the relative error of the calculated crack width is greater than 10% before and after the modification of the formula.The modified formula is more reasonable to reflect the calculation results of crack width of FRP reinforced concrete slab.The relative error of the crack width is less than 3% before and after the modification of tensile stress,the modification result has less influence on crack width.%基于FRP筋混凝土梁裂缝宽度计算公式研究了FRP筋混凝土板裂缝宽度的计算方法,探讨了板与梁结构特征差异对裂缝宽度计算的影响机理.引入平均裂缝间距、截面内力臂系数、FRP筋应变不均匀系数等参数的修正方法,建议取消对有效配筋率下限值的规定.利用该方法对FRP筋混凝土板在不同的有效配筋率和受拉区FRP筋应力影响下的裂缝宽度进行了计算.结果表明:有效配筋率<0.01,公式修正前后计算得到的裂缝宽度相对误差均>10%.修正后的公式更能合理反映FRP筋混凝土板裂缝宽度的计算结果;公式中受拉区FRP筋应力修正前后得到的裂缝宽度相对误差均<3%,其修正结果对构件裂缝宽度变化影响较小.