锈蚀钢筋混凝土梁抗剪承载力计算的概率模型

该文针对锈蚀钢筋混凝土（RC）梁抗剪承载力计算的传统确定性模型所存在的缺陷，研究建立了锈蚀RC梁抗剪承载力计算的概率模型。首先综合考虑钢筋锈蚀对箍筋屈服强度、配筋率、配箍率、临界斜裂缝倾角、梁有效抗剪截面积等重要因素的影响，结合修正压力场理论和考虑剪跨比影响的临界斜裂缝倾角模型，建立了锈蚀RC梁抗剪承载力计算的确定性模型；然后综合考虑客观不确定性和主观不确定性的影响，结合贝叶斯理论和马尔科夫链蒙特卡洛（MCMC）法，建立了锈蚀RC梁抗剪承载力计算的概率模型；最后通过与试验数据和传统确定性抗剪承载力计算模型的对比分析，验证了该概率模型的有效性和适用性。分析结果表明，所建立的概率模型不仅可以合理描述锈蚀RC梁抗剪承载力的概率分布特性，而且可以校准传统确定性抗剪承载力模型的计算精度和置信水平，具有良好的有效性和适用性。

PROBABILISTIC MODEL FOR SHEAR STRENGTH OF CORRODED REINFORCED CONCRETE BEAMS

To overcome the disadvantage of traditional deterministic shear strength models for corroded reinforced concrete (RC) beams, a probabilistic model for shear strength of corroded RC beams was established. Based on the modified compression field theory (MCFT) and the critical diagonal crack angle model considering the influence of shear span ratios, a deterministic model for shear strength of corroded RC beam was established which takes into account the influence of reinforcement corrosion on various important factors such as the yield strength of transverse steel, stirrup reinforcement ratio, stirrup ratio, critical diagonal crack angle, sectional area of RC beam. Then a probabilistic model for the shear strength of corroded RC beam was developed by using the Bayesian theory and the Markov Chain Monte Carlo (MCMC) to take into account the influences of both epistemic and aleatory uncertainties. Finally, the applicability and efficiency of the proposed probabilistic model were validated by comparing it with the experimental data and traditional deterministic models. The analysis results show that the proposed probabilistic model is of good accuracy and applicability, because it can not only describe the probabilistic characteristics of shear strength of corroded RC beam, but also provide a benchmark to calibrate the confidence level and accuracy of traditional deterministic shear strength models.