一种箍筋约束混凝土峰值应力的概率模型

该文首先基于多轴受力情况下混凝土材料的极限强度面和Willam-Warnke五参数破坏准则，结合144组箍筋约束混凝土棱柱体的试验数据，建立了箍筋约束混凝土峰值应力的确定性模型；然后综合考虑主观不确定性和客观不确定性的影响，结合贝叶斯理论和马尔科夫链蒙特卡洛法，建立了箍筋约束混凝土峰值应力的概率模型；最后通过与试验数据和传统确定性模型的对比分析，验证了该概率模型的有效性和适用性。分析结果表明，该概率模型不仅能够合理描述箍筋约束混凝土峰值应力的概率特性，而且能够校准确定性模型的置信水平和预测精度，还可以确定具有预定置信水平的箍筋约束混凝土峰值应力的概率特征值。

A PROBABILISTIC MODEL FOR PEAK STRESS OF CONCRETE CONFINED BY TIES

Based on the ultimate strength surface of concrete under multiaxial stress and the Willam-Warnke five parameter failure criterion, a deterministic model for the peak stress of concrete confined by ties was established by combining with 144 groups of test data of prism concrete specimens confined by ties. Then, taking into account the influence of both epistemic and aleatory uncertainties, a probabilistic model for the peak stress of concrete confined by ties was established by the Bayesian theory and the Markov chain Monte Carlo method. The accuracy and applicability of the model were validated by comparing with the experimental data and the traditional deterministic models. The analysis results show that the proposed probabilistic model can reasonably describe the probabilistic characteristics of the peak stress of concrete confined by ties, since it can not only calibrate the confidence level and accuracy of existing deterministic models, but also determine the probabilistic characteristic value of the peak stress of concrete confined by ties corresponding to the predefined confidence level.