FRP筋混凝土T形和矩形截面梁抗弯承载力计算方法

METHOD OF CALCULATING THE FLEXURAL STRENGTH OF FRP REINFORCED CONCRETE T-SHAPED AND RECTANGULAR BEAMS

为建立纤维增强复合材料(fiber-reinforced polymer,FRP)筋混凝土T形和矩形截面梁抗弯承载力简化计算方法,根据平衡破坏状态下的截面分析,定义了等效FRP配筋率ρ_(ef)和相应的平衡配筋率ρ_(ef,b)。在此基础上,基于257根FRP筋混凝土梁试验结果的统计分析,改进了受拉破坏和受压破坏皆可能发生的过渡区范围(ρ_(ef,b)<ρ_(ef)≤1.5_(ρef,b))。编制了受拉破坏控制截面的非线性分析程序,考虑多个设计参数的影响,开展了25344个截面的参数分析。通过对参数分析结果的多元回归分析,推导了受拉破坏控制截面的抗弯承载力简化计算公式。此外,基于截面内力平衡和协调条件,推导了受压破坏控制截面的抗弯承载力计算公式。以国内外257根梁抗弯承载力试验结果,验证了所提方法的适用性。

To establish a simplified method of calculating the flexural strength of concrete T-shaped and rectangular beams reinforced by fiber-reinforced polymer(FRP)bars,the effective FRP reinforcement ratioρ_(ef) and the corresponding balanced reinforcement ratioρ_(ef,b) were firstly derived from cross-section analyses under balanced failure.In conjunction with a statistical analysis of the experimental results of 257 FRP reinforced concrete(RC)beams,the transition region,where tensile failure and compressive failure were possible,was revised(ρ_(ef,b)<ρ_(ef)≤1.5_(ρef,b)).A numerical sectional analysis of tension-controlled sections was used for a detailed parametric study of a total of 25344 sections.Based on a multiple regression analysis of the numerical results,simplified equations were developed for the flexural strength of tension-controlled sections.Besides,design equations were presented for the flexural strength of compression-controlled sections based on the fundamentals of the equilibrium of forces and the compatibility of strains.An experimental database of 257 beams was established and used to verify the accuracy of the proposed approach.