退化钢筋混凝土桥梁概率耐久性评估方法

提出了考虑时间、空间变异特性的退化钢筋混凝土桥梁耐久性概率评估的随机有限元方法.首先,通过考虑钢筋与混凝土之间时变的粘结滑移关系及腐蚀钢筋的应力应变关系,采用弥散裂纹方法对退化钢筋混凝土桥梁进行有限元分析.然后,提出了退化钢筋混凝土桥梁耐久性概率评估的随机有限元分析方法,基于文献及现场调查的数据,采用蒙特卡罗仿真方法对钢筋均匀及点锈蚀、混凝土保护层厚度、表面氯离子含量、氯离子扩散系数及腐蚀率等进行随机抽样,考虑这些时变及空间变异的因素对钢筋混凝土桥梁可靠度的影响.最后,以天津滨海新区的一座钢筋混凝土梁桥为例分析了所提方法的应用.

Probabilistic durability assessment approach of deteriorating RC bridges

A stochastic finite element computational methodology for probabilistic durability assessment of deteriorating reinforced concrete (RC) bridges by considering the time- and spacedependent variabilities is presented. First, finite element analysis with a smeared cracking approach is implemented. The timedependent bond-slip relationship between steel and concrete, and the stress-strain relationship of corroded steel bars are considered.Secondly, a stochastic finite element-based computational framework for reliability assessment of deteriorating RC bridges is proposed. The spatial and temporal variability of several parameters affecting the reliability of RC bridges is considered.Based on the data reported by several researchers and from field investigations, the Monte Carlo simulation is used to account for the uncertainties in various parameters, including local and general corrosion in rebars, concrete cover depth, surface chloride concentration, chloride diffusion coefficient, and corrosion rate. Finally, the proposed probabilistic durability assessment approach and framework are applied to evaluate the time-dependent reliability of a girder of a RC bridge located on the Tianjin Binhai New Area in China.