林拥军, 徐文强, 杨敏润, 奉鑫, 余国菲. 基于三维能量屈服准则的新老混凝土无锚筋结合面抗剪强度统一计算方法[J]. 工程力学, 2022, 39(5): 119-132. DOI: 10.6052/j.issn.1000-4750.2021.02.0149
引用本文: 林拥军, 徐文强, 杨敏润, 奉鑫, 余国菲. 基于三维能量屈服准则的新老混凝土无锚筋结合面抗剪强度统一计算方法[J]. 工程力学, 2022, 39(5): 119-132. DOI: 10.6052/j.issn.1000-4750.2021.02.0149
LIN Yong-jun, XU Wen-qiang, YANG Min-run, FENG Xin, YU Guo-fei. UNIFIED CALCULATION METHOD FOR SHEARING STRENGTH OF NEW-TO-OLD CONCRETE INTERFACE WITHOUT ANCHOR BARS BASED ON THREE-DIMENSIONAL ENERGY YIELD CRITERION[J]. Engineering Mechanics, 2022, 39(5): 119-132. DOI: 10.6052/j.issn.1000-4750.2021.02.0149
Citation: LIN Yong-jun, XU Wen-qiang, YANG Min-run, FENG Xin, YU Guo-fei. UNIFIED CALCULATION METHOD FOR SHEARING STRENGTH OF NEW-TO-OLD CONCRETE INTERFACE WITHOUT ANCHOR BARS BASED ON THREE-DIMENSIONAL ENERGY YIELD CRITERION[J]. Engineering Mechanics, 2022, 39(5): 119-132. DOI: 10.6052/j.issn.1000-4750.2021.02.0149

基于三维能量屈服准则的新老混凝土无锚筋结合面抗剪强度统一计算方法

UNIFIED CALCULATION METHOD FOR SHEARING STRENGTH OF NEW-TO-OLD CONCRETE INTERFACE WITHOUT ANCHOR BARS BASED ON THREE-DIMENSIONAL ENERGY YIELD CRITERION

  • 摘要: 已有新老混凝土无锚筋结合面抗剪强度的计算方法分为考虑正应力和不考虑正应力2类,两类方法不仅存在理论依据不充分的问题,而且计算精度也有待提高,能够考虑正应力以及正应力为0的统一计算公式还未见报道。根据剪切试验破坏特征、机理,分析新老混凝土无锚筋结合面破坏机构,基于三维能量屈服准则、虚功原理和塑性极限分析理论,详细推导新老混凝土无锚筋结合面抗剪强度理论计算公式。引入考虑正应力和粗糙度的综合影响系数,基于已有剪切试验数据并借助三维曲线拟合技术对理论公式进行修正,得到新老混凝土无锚筋结合面抗剪强度统一计算公式。采用不同方法对27个新老混凝土无锚筋结合面压(拉)剪复合受力试验试件以及30个新老混凝土无锚筋结合面纯剪试验试件进行抗剪强度计算,对比分析结果表明:统一计算方法理论依据充分、计算简便,既可用于压(拉)剪复合受力构件,也可应用于纯剪受力构件;对于压(拉)剪复合受力试验试件,该文方法计算值与试验值的偏差率大都在±15%以内,统一计算公式的计算精度高于已有考虑正应力的计算方法;对于纯剪试验试件,该文方法计算值的偏差率大都在±20%以内,除计算低强度混凝土试件偏差率较大之外,统一计算公式的计算精度明显高于已有不考虑正应力的计算方法。

     

    Abstract: There are two types of calculation methods for the shear strength of the existing new-to-old concrete interface without anchor bars: considering normal stress and without considering normal stress. These methods lack theoretical support and need to improve the calculation accuracy. A unified calculation formula that takes into account both normal stress and zero normal stress has not been reported. According to the shear test failure phenomenon and the new-to-old concrete interface mechanism, the failure mechanism of a new-to-old concrete interface without anchor bars is analyzed. Based on the three-dimensional energy yield criterion, on virtual work principle and, on plastic limit analysis theory, the theoretical calculation formula of shear strength of new-to-old concrete interface without anchor bars is derived. The comprehensive coefficient considering the influence of normal stress and of roughness is introduced. The theoretical formula is modified using three-dimensional curve fitting based on the existing shear test data of new-to-old concrete interface without anchor bars. A unified calculation formula of shear strength of new-to-old concrete interface without anchor bars is obtained. Based on 27 groups of compressive (tensile) shear test specimens and on 30 groups of pure shear test specimens of the new-to-old concrete interface without anchor bars, different methods are used to calculate the shear strength, and a comparative analysis is conducted. The results show that: for the compressive (tensile) and shear test specimens, the deviation between the calculated values and experimental values of the method is generally less than 15%, and the calculation accuracy of the unified formula is higher than that of the existing calculation methods considering normal stress. For pure shear test specimens, the deviation rates of the calculated values of the method proposed are mostly within 20%. Except for the large deviation rate of low strength concrete specimens, the calculation accuracy of the unified formula is much higher than that of the existing calculation formula without considering the normal stress. The unified calculation method has a sufficient theoretical basis and is simple in computation. It can be applied to compressive (tensile) shear composite members and pure shear members. Meanwhile, the calculation accuracy is better than that of the existing calculation methods.

     

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