钢筋增强延性水泥基复合材料梁弯曲承载力计算的实用设计方法

Practical Design Approach for Calculating Flexural Capacity of Steel Reinforced Ultra-high Toughness Cementitious Composite Bending Beams

针对钢筋增强超高韧性水泥基复合材料RUHTCC受弯构件,开展了其正截面承载力计算实用设计方法的研究工作.依据等效矩形方法,假定UHTCC单轴受压模型为非线性模型,理论预测了RUHTCC构件的弯曲承载力,并与试验结果和按UHTCC双线性单轴受压模型的计算结果进行对比.结果发现,两种受压模型的理论预测值相差微乎其微,且均与试验吻合较好,证实了在弯曲设计中采用非线性受压模型的合理性.引入受压区高度增大系数η,分析了UHTCC和纵筋抗弯贡献的变化规律,给出了考虑UHTCC抗弯贡献的纵筋配筋率上限建议值.

A study on a practical design approach for calculating normal section bending capacity of reinforced ultra-high toughness cementitious composite RUHTCC bending beams was done.According to equaivalent rectangular stress-block method,the flexural capacity of RUHTCC beams was analytically predicted by assuming a nonlinear UHTCC unaxial compressive model in compression zone and was compared with the experimental results obtained from the RUHTCC bending tests and the calculated ones according to bilinear UHTCC unaxial compression models.The results showed that the theoretical predictions obtained according to two compression models had small difference and agreed well with the experimental measurement,which verified the rationality of nonlinear compression model in the design of RUHTCC flexural members.By introducing compression zone height enhacenemnt coefficient η,the developing tendency of both UHTCC and steel bar contribution to flexural load during the entire loading were estimated.The upper limit for longitudinal reinforcement ratio beyond which the contribution of UHTCC can be ignored was suggested.