基于MCFT的高强轻骨料混凝土框架中节点受剪承载力计算方法

Calculation Method for Shear Capacity of High-strength Lightweight Aggregate Concrete Frame Interior Joints Using Modified Compression Field Theory

根据低周反复荷载作用下不同轴压比的4个不同核心区配箍率高强轻骨料混凝土框架中节点抗震性能试验结果,主要研究了该类构件的破坏特征以及受剪性能。在试验研究基础上,结合高强轻骨料混凝土破坏特性,选取合适的节点受剪核心区,修正骨料粒径计算参数,建立了基于修正压力场理论(MCFT)的高强轻骨料混凝土框架中节点受剪承载力计算模型,同时收集13个轻骨料混凝土框架中节点试验结果,应用该模型计算了包含17组该类构件的受剪承载力,并将理论值与试验值进行比较分析。结果表明:该类构架的破坏特征与普通混凝土中节点破坏特征类似,均经历了初裂、通裂、极限和破坏4个典型破坏阶段,且试验结果与应用基于修正压力场理论的高强轻骨料混凝土框架中节点受剪承载力计算模型计算结果之比的均值为0.907,方差为0.008,两者吻合较好,验证了模型的准确性与合理性,该模型可以应用于该类构件的极限受剪承载力计算,同时该理论有明确的力学理论和计算过程,可以较为清楚地反映构件初裂、通裂、极限阶段的受力过程。

According to the seismic performance test results of the high-strength lightweight aggregate concrete（HSLAC）frame interior joints in 4 different stirrup ratios of core area under reversed quasi-static cyclic loading,the failure characteristics and shear behavior were mainly studied.Based on the experimental research and combined with the failure characteristics of HSLAC,through selecting suitable joint shear core area and modifying aggregate particle size calculation parameters,a calculation model for the shear capacity of HSLAC frame interior joints based on modified compression field theory（MCFT） was established.Then collected 13 lightweight aggregate concrete frame interior joint test results,the shear strengths of 17 specimens were calculated based on the model,the calculated results were compared with the testresults.The results indicate that the failure characteristic of the member similar to that of normal concrete specimens,all HSLAC specimens experience cracking,yield,ultimate and failure during the failure process.The average value of the ratio between the test results and the calculated results of the proposed model is 0.907 and the variance is 0.008,the values are in good agreement,which verifies the accuracy and rationality of the proposed model.The model can be applied to the calculation of ultimate shear capacity of the kind of member,and the theory has definite mechanics theory and calculation process,can reflect the mechanical process of cracking,yield,ultimate and failure of the member more clearly.