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现有的钢筋混凝土(RC)柱抗剪承载力计算模型大多属于确定性模型,难以有效考虑几何尺寸、材料特性和外荷载等因素存在的不确定性,导致计算结果的离散性较大,且计算精度和适用性有限。鉴于此,该文结合变角桁架-拱模型和贝叶斯理论,研究建立了剪切型RC柱抗剪承载力计算的概率模型。首先基于变角桁架-拱模型理论,并考虑轴压力对临界斜裂缝倾角的影响,建立了剪切型RC柱抗剪承载力的确定性修正模型;然后考虑主观不确定性和客观不确定性因素的影响,结合贝叶斯理论和马尔科夫链蒙特卡洛(MCMC)法,建立了剪切型RC柱的概率抗剪承载力计算模型;最后通过与试验数据和现有模型的对比分析,验证了该模型的有效性和实用性。分析结果表明,该模型不仅可以合理描述剪切型RC柱抗剪承载力的概率分布特性,而且可以校准现有确定性计算模型的置信水平,并且可以确定不同置信水平下剪切型RC柱抗剪承载力的特征值。
Most of the existing RC (RC) columns’ shear strength calculation models belong to the deterministic model, so it is difficult to effectively consider the uncertainties such as geometrical size, material properties and external load, which leads to large discretization of the results. Calculation accuracy and applicability are limited. In view of this, this paper combines the variable angle truss-arch model and Bayesian theory to establish the probability model of shear RC column shear strength calculation. Firstly, based on the theory of variable angle truss-arch model, considering the influence of axial pressure on the inclination of critical oblique fractures, a deterministic correction model of shear strength of RC columns with shear is established. Then, the subjective uncertainty and objective uncertainty The influence of factors, combined with Bayesian theory and Markov chain Monte Carlo (MCMC) method, established shear RC column model of the calculation of the probability of shear capacity; and finally with the experimental data and the existing model of comparative analysis , Validated the validity and practicability of the model. The analysis results show that this model not only can reasonably describe the probability distribution characteristics of shear RC columns, but also can calibrate the confidence level of the existing deterministic calculation models, and can determine the shear RC column resistance Characteristic value of shear capacity.