小跨高比混凝土三点弯曲梁双K断裂参数研究

DOUBLE-K FRACTURE PARAMETERS OF CONCRETE IN THREE-POINT BENDING BEAMS WITH SMALL SPAN-DEPTH RATIOS

  • 摘要: 采用小跨高比三点弯曲梁研究了混凝土的断裂性能。基于对跨高比为2.5和4的三点弯曲梁断裂参数计算公式的线性插值,给出了计算小跨高比三点弯曲梁断裂参数的公式。通过开展3种小跨高比三点弯曲梁试验及文献中的试验数据对该文公式进行了验证,结果表明:随试件高度从100 mm增大至200 mm,基于小跨高比三点弯曲梁所得的起裂断裂韧度基本保持不变,而失稳断裂韧度则逐渐增大,但增幅较小。该文所给公式计算所得的双K断裂参数与文献中已有方法所得结果基本相同。解析法得到的起裂断裂韧度与试验法所得结果吻合较好。通过对文献中的试验数据的分析,进一步验证了该文所给的方法可以用于研究小跨高比三点弯曲梁的断裂性能。

     

    Abstract: Three-point bending (TPB) beams with small span-depth ratios were utilized to research the fracture properties of concrete. An approach for determining the fracture parameters of TPB beams with small span-depth ratios was provided, which was based on linear interpolation between the calculation formulas of TPB beams with the span-depth ratios of 2.5 and 4. The experimental results of TPB specimens with three small span-depth ratios and the available results in the literature were used to verify the present formulae. The results indicate that when the specimen depth was increased from 100 mm to 200 mm, the obtained initial fracture toughness remained constant, while the unstable fracture toughness increased gradually but the growth was small. The obtained double-K fracture parameters by the presented method were in good agreement with the results determined by the method proposed in the literature. The initial fracture toughness obtained by the analysis method agreed well with those obtained by the experimental method. The applicability of the presented method to TPB beams with small span-depth ratios was further verified by the experimental data in the literature.

     

/

返回文章
返回