混凝土断裂过程及尺寸效应分析

为研究混凝土裂纹断裂过程和最大承载力计算方法,通过实验机对四种不同尺寸混凝土紧凑拉伸断裂试件进行了加载过程实验,并对其中一个试件进行应变片跟踪测试.由实验结果分析得到了一系列关系曲线,如试件的载荷-加载点位移关系曲线,断裂损伤区变形随载荷变化曲线;并且计算了不同尺寸断裂试件的应力强度因子.结合计算粘聚裂纹应力强度因子的公式与断裂准则,完成了对承载力理论值的计算,并将其与实验峰值平均值进行对比,其结果是两者相比误差较小,表明此种计算裂纹结构最大承载力方法是可行的.

Analysis of Concrete Fracture Process and Size Effect

In order to investigate fracture process of concrete crack and calculation method of specimen's maximum bearing capacity, concrete compact tension fracture specimens, which had four different sizes, were tested, and one of the specimens was measured by electrical strain gages equipment. Based on experimental results, a series of curves were obtained and analyzed, such as curves of loading point displacement vs variable loading on the typical specimens, and curves of fracture damaged area deformation vs loading. The stress intensity factor of specimens with different size fracture was calculated. For specimens with different sizes, the computation method of structure bearing capacity was presented through the stress intensity factor's computation formula and the fracture criterion. The calculated value of this theoretical method was compared with the experimental mean peak values, and the relative error of them is small. This indicates that the method of estimating structures' maximum bearing capacity is feasible.