The Method Of Probability Analysis And Design Of Durability Based On Carbonation Life Criterion

Considering some insufficient for durability design code stipulated. This paper showed that the complete structure durability design should include three parts of contents: Structure overall plan, technical standards of materials, in view of structure durable analysis design and detail structure design.The mechanism of concrete carbonation, influence factors and influence to structure durable under Normal Air Environment was researched. And based on have discussed the relations of concrete cover thickness and durability, the carbonization depth of concrete was calculated according to the forecast model of carbonation. And compared to the concrete cover thickness of code stipulated, the results show that the fortification level of our country about cover thickness was somewhat low, it is necessary to increase the cover thickness further to enhance the durable level of structures.One method of probability analysis of durability was proposed depended on Normal Air Environment, and equation of durable limit states was established. According to the values of actual project, the concrete cover thickness C and the concrete carbonation rate coefficient A were statistical analyzed, their probabilistic were determined, and corresponding statistical parameters were calculated.This paper adopted 'the calibration method' to determine the suggests value of the carbonation target reliability index, and established the probabilistic design expression to durability design corresponded to specific limit state under defined design working life. This expression is similar to current reliability design of structural bearing capacity, and adopted partial coefficient γ to reflect structural reliability index.This method proposed will facilitate designers to consider the durable question in the structural design, hoped this research results will be able to provide the reference for our country durability design aspect research.