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

由于我国降低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，因此各建筑公司和软件公司已经开发了一些计算机程序，但几乎所有程序都采用确定性方法，而没有考虑与结构安全和可靠性相关的物理不确定性，如材料强度、施工现场环境等。另一方面，考虑到结构安全性不可避免的不确定性，采用概率方法对结构安全性进行数值估算，根据国际标准化组织ISO 2394推荐的用可靠性指标评估结构安全性和可靠性的方法，基于结构可靠性理论，编制了能够计算盐害下钢筋混凝土结构构件寿命周期费用的计算程序。根据裂缝宽度和可靠度指标分别对盐害构件的修复和加固进行了判断，编制了钢筋混凝土构件盐害期望寿命验算程序。此外，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研究，得到了一些与维修计划有关的有用结果。

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.