BFRP筋混凝土深梁动态剪切破坏尺寸效应模拟

Simulations of size effect on dynamic shear failure of BFRP-reinforced concrete deep beam

为研究玄武岩纤维增强聚合物(BFRP)筋混凝土深梁动态剪切破坏机制及其尺寸效应规律,考虑混凝土非均质性、混凝土/BFRP筋相互作用以及混凝土和BFRP筋在材料层面的应变率效应,建立了BFRP筋混凝土深梁细观尺度三维数值模型。利用已有的试验数据验证了该数值模拟方法的合理性和准确性,采用该方法研究了不同尺寸但几何相似的BFRP筋混凝土深梁在不同应变率下的剪切破坏模式及失效机制。分析了截面尺寸、配箍率、应变率对BFRP筋混凝土深梁剪切破坏及相应尺寸效应规律的影响。结果表明:动载下梁的破坏模式与静载时存在较大差异,但均表现出尺寸效应;增大应变率及配箍率均能有效提高梁承载力且削弱剪切尺寸效应,但应变率的作用程度明显大于配箍率。

In order to investigate the dynamic shear failure mechanism and size effect law of deep concrete beams with Basalt Fiber Reinforced Polymer(BFRP)bars,a three-dimensional meso-scale numerical model of BFRP reinforced concrete deep beams was established considering concrete heterogeneity,concrete/BFRP reinforcement interaction,and strain rate effect of concrete and BFRP bars in material level.Firstly,the rationality and accuracy of the numerical simulation method are verified by the existing ex⁃perimental data.Then,the shear failure modes and failure mechanisms of the geometrical-similar BFRP-reinforced concrete deep beams with different sizes under different strain rates were studied by the numerical simulation method.The influence of beam depth,stirrup ratio and strain rate on the shear failure of BFRP-reinforced concrete deep beams and the corresponding size effect law were analyzed.The results indicate that:The failure modes of beams under dynamic loading are different from those under stat⁃ic loading,but they all show size effect;Both the strain rate and the stirrup rate can effectively improve the bearing capacity of the beam and weaken the shear size effect,but the effect of strain rate is significantly greater than that of stirrup rate.