Durability Assessment Based on Design-value Method for Structure Design

A significant durability assessment for structure design is devoted to guarantee the necessary service life for its safety and sustainability. A flexible probability assessment method here is improved based on the corrosive cracking life criterion theory model used in China and improved the design-value method mentioned in ISO2394. It first built an assessment expression consisted of design values and service life, considering limit state function and First Order Reliability Methods (FORM). Then, it took into account the uncertainties and variability about the main random variables in this assessment expression: concrete cover thickness, compressive strength and carbonation depth calculation model uncertainty factor, ignored the secondary variables with little variability. Last, by introducing and improving design-value method, it can directly calculate the service life with flexibly reliability index chosen for durability design assessment. This calculation results are easy to contrast with the target index to assess. Without traditional reliability calculation, it flexibly evaluated durability design with reliability index of safety results.