Evaluation of structural reliability of reinforced concrete structure in consideration for inevitable uncertainty and probabilistic appraisal of its life cycle cost

由于我国削减成本的政策之一是使各种机构和结构的生命周期成本最小化，一些计算机程序已由各自的建筑公司和软件公司开发。然而，在大多数方案中采用确定性方法，而不考虑与结构安全性和可靠性相关的物理不确定性，如材料强度、建筑工地环境等。另一方面，考虑结构不可避免的不确定性，采用概率方法对结构的安全性进行数值估计。本文根据国际标准化组织ISO 2394推荐的用可靠度指标评价结构安全可靠度的方法，基于结构可靠度理论，开发了计算钢筋混凝土结构构件在盐损伤下的寿命周期成本的计算机程序。采用裂缝宽度和可靠度指标分别对受盐腐蚀的构件进行修复和加固。本研究的结果是开发了计算机程序，通过该程序可以首先评估钢筋混凝土结构构件在盐损伤下的预期LCC。利用所开发的程序，对钢筋混凝土结构的维修计划进行了参数化研究，得到了一些有用的结果。

Since one of our country policies toward cost curtailment is minimization of the life cycle cost of various institutions and structures, some computer programs have been developed by respective construction companies and software firms.However, deterministic approach in almost programs is adopted without regard to the physical uncertainties related to structural safety and reliability such as material strength, circumstances of construction sites, others. On the other hand, probabilistic method is used to estimate numerically the structural safety in consideration for their inevitable uncertainties.In this study, a computer program which is able to be calculated the life cycle cost of reinforced concrete structure members under damage from salt was developed based upon structural reliability theory, because the method to evaluate structural safety and reliability with reliability index is recommended in International Organization for Standardization, namely ISO 2394. Repair and reinforcement of a structural member subjected to deterioration by salt are judged by crack width and reliability index respectively.The result of this study is to develop the computer program by which expected LCC of a reinforced concrete structural member under damage from salt is able to be valuated first. Further, some useful results related to maintenance plan of reinforced concrete structures were obtained based upon parametric studies by usage of the developed program.