THE ROLE OF DURABILITY IN RELIABILITY-BASED DESIGN OF COMPOSITE MATERIALS FOR CIVIL STRUCTURES

Design guidelines for fiber-reinforced polymers (FRP) used in critical structures must take into account the loss of stiffness and strength these materials experience in service over time. Reliability based design accounts for these losses by the use of reduction factors. These design reduction factors should include scientific and rational backing. In the civil infrastructure, the American Association of State Highway Transportation Officials (AASHTO) load resistance factor design (LRFD) uses statistical methods in structural design, including a strength reduction factor for a particular combination of loads. This approach is very attractive for composite structures as it accounts for the service environment. In this paper, we propose a durability simulation method that combines LRFD and a material property evolution scheme to predict the future reliability of a FRP structure and allows one to rationally select reduction factors given a preselected probability of survival.