钢筋混凝土受剪梁裂纹分形演化特征试验

Fractal Evolution Characteristics Experiment of Shear Cracks in Reinforced Concrete Beams

通过5片不同剪跨比和箍筋配筋率钢筋混凝土梁受剪试验,应用计盒法研究了混凝土梁受剪裂纹扩展规律的分形特征。研究了剪跨比和箍筋配筋率对裂纹分形特征的影响,并分析了裂纹分形维数与荷载、挠度之间的关系。研究结果表明:混凝土梁受剪裂纹具有明显的分形特征,随荷载增大,裂纹分形维数线性增大,分形维数为0.9769~1.2767。随剪跨比增大,裂纹分形维数增长速率加快。随箍筋配筋率增大,裂纹分形维数增长速率降低。试验梁跨中挠度随裂纹分形维数增大而增大,两者成幂函数关系,且随箍筋配筋率和剪跨比增大,挠度随分形维数增长的速率降低。

The fractal characteristics of shear crack growth of concrete beams were analyzed by box counting method through shear experiment of five beams with different shear span ratio and stirrup reinforcement ratio.The effects of shear span ratio and stirrup reinforcement ratio on the fractal characteristics of cracks were studied.The results show that the shear crack of concrete beam has obvious fractal characteristics.The fractal dimension linearly increases with the increase of load,and the fractal dimension is 0.9769~1.2767.The growth rate of the fractal dimension increases with the increase of shear span ratio,and tends to decrease with the increase of stirrup reinforcement ratio.The mid-span deflection of the test beam increases with the increase of the fractal dimension of the crack,and the relationship of them is power function relationship.With the increase of stirrup reinforcement ratio and shear span ratio,the deflection decreases with the increase of fractal dimension.