钢筋钢纤维混凝土地下结构构件承载力计算方法研究

Calculation Methods for the Bearing Capacity of SFRC Underground Structure Members

文章详细介绍了我国和欧洲规范中关于钢筋钢纤维混凝土地下结构承载力的计算理论和方法,通过实际算例对比分析了二者的主要区别,指出了我国规范计算方法存在的不足,并提出了建议。理论分析和计算结果表明:正截面极限承载力设计理论方面,两者计算结果基本相同;斜截面承载力计算理论则有所不同,主要区别在于按我国规范计算的受弯梁抗剪力大于欧洲规范计算值,并且随着梁高、混凝土等级提高,差距越大;欧洲规范考虑了纵向受拉钢筋的抗剪作用,且轴向压力的影响系数大于我国规范值;关于正常使用极限状态承载力计算,按我国规范可减小裂缝宽度约为10%,而欧洲规范则约为60%,这是影响配筋率的主要因素之一。文章研究结论可以为我国钢筋钢纤维混凝土构件的设计方法和我国规范相关内容优化提供参考,可以更好地推广钢筋钢纤维混凝土在我国土木工程行业的应用。

This paper presents the deficiencies of the calculation method for the bearing capacity of SFRC underground structures in Chinese code, compares it with the Eurocode through case studies and gives relevant suggestions. The results show that： 1） the design methods and calculation formulas in the Chinese code and Eurocode are roughly the same in respect to the ultimate bearing capacity of normal sections, while they are different in the bearing capacity of oblique sections-the shearing resistance of the bending beam under the Chinese code is greater than that under the Eurocode, and the higher the beam height and the concrete grade, the greater the difference; 2） the Eurocode not only considers the shearing resistance of longitudinal tensile reinforcement but also has a greater influence coefficient of axial compressive force compared with the Chinese code; and 3） crack width can be reduced by 10% at a serviceability limit state under the national code, but much less than 60% under the Eurocode, and this is one of the main influence factors of the reinforcement ratio.