The probability expression for concrete structure carbonization durability design

With the development of the construction process and the different reliability options, the current method of durability design is increasingly showing its limitations on the side of flexibility, generality and accuracy for reliability control. According to the combination of theory and experience carbonation depth model, choosing the latest statistical data, considering the concrete protective cover thickness, compressive strength and carbonation depth calculation model uncertainty factor as the basic random variables, the paper puts forward the function of the structure about time. Drawing lessons from the basic idea of design-value method, with the basis of the existing structure reliability theory, considered directly of the influence of basic variables probabilistic properties, target reliability index and design working life to design result, and the design values are expressed as the product of reference design value and partial factor, it set up the probability expression of concrete structure durability design based on the rule of carbonation life. The influence of target reliability index roundly by each partial factors, which is benefit to reliability control. This durability design method is suitable for concrete structure design which not allowing the steel corrosion in any design working life under common atmosphere environment. Based on the expression, the protective cover thickness and concrete strength can be directly designed for the require of the durability with the new material, new technology to meet different reliability index and design working life.