FRP筋-ECC梁受弯性能

Flexural Behavior of FRP-reinforced ECC Beam

为探究纤维增强复合材料筋增强高延性纤维增强水泥基复合材料梁(FRP筋-ECC梁)的受弯性能,对其正截面受弯全过程进行了理论分析和数值计算。首先,基于平截面假定和材料本构模型,获得FRP筋增强ECC梁受弯全过程截面应力分布,推导各受力阶段正截面受弯承载力计算公式;采用MATLAB进行数值计算,对FRP筋-ECC梁受弯全过程进行分析;将计算获得的荷载-挠度曲线与已有试验曲线对比,验证模型的正确性。然后,基于所提出的理论模型进行参数分析,分析ECC抗压强度及FRP筋配筋率对梁受弯性能的影响。最后,基于所提出的FRP筋-ECC梁延性系数计算公式,分析FRP筋配筋率及ECC抗压强度对梁延性性能的影响,并指出FRP筋-ECC梁的延性变化与梁的破坏模式有很大相关性。结果表明:ECC抗压强度和FPR筋配筋率的变化均可改变梁的破坏模式,但FRP筋配筋率的影响更大;ECC抗压强度对梁的初裂荷载、极限承载能力有较大影响;配筋率可明显提高梁的短期刚度和极限承载力,但对梁的初裂荷载影响较小。

In order to investigate the flexural behavior of fiber reinforced polymer(FRP)-reinforced engineered cementitious composites beam(FRP-reinforced ECC beam),the theoretical analysis and numerical calculation of the whole normal-section bending process were carried out.Firstly,based on the plane section assumption and the constitutive model of materials,the stress distribution of FRP-reinforced ECC beam during the whole bending process was obtained,and the formula for calculating normal-section flexural capacity was derived at each loading stage.The whole bending process of FRP-reinforced ECC beam was analyzed by numerical calculation with MATLAB.The correctness of the model was verified by comparing the calculated load-deflection curves with the existing test results.Then,based on the proposed theoretical model,the influence of ECC compressive strength and FRP reinforcement ratio on the flexural performance of the beam was analyzed.Finally,based on the proposed ductility coefficient calculation formula of FRP-reinforced ECC beam,the influence of FRP reinforcement ratio and ECC compressive strength on the ductility of beam was analyzed,and it was pointed out that the ductility change of FRP-reinforced ECC beam was closely related to the failure mode of beams.The results show that the change of ECC compressive strength and FPR reinforcement ratio can change the failure mode of the beam,but the influence of FRP reinforcement ratio is greater.ECC compressive strength has great influence on the initial crack load and ultimate bearing capacity of the beam.The reinforcement ratio can significantly improve the short-term stiffness and ultimate bearing capacity of the beam,but has little effect on the initial crack load of the beam.