Toward Load and Resistance Factor Design for Fiber-Reinforced Polymer Composite Structures

Abstract

Advanced fiber-reinforced polymer (FRP) composites, which have been favored for certain aerospace, military, marine, and automotive applications, now are starting to be introduced in buildings, bridges, and other civil construction, where their desirable properties can enhance performance. A load and resistance factor design (LRFD) standard for composites would facilitate their use in civil infrastructure, creating a market for new FRP building materials by providing a basis for structural design that is comparable with existing LRFD standards for other common construction materials. Such a specification must take into account the distinguishing features of FRP composites: Their orthotropic nature, sensitivity to moisture, temperature, and ultraviolet effects, dependence of strength and stiffness on the rate of application and duration of structural loads, and uncertainties in their mechanical and structural properties. The structural reliability tools needed to develop an LRFD standard are at hand. However, at present, only rudimentary statistical databases required to support this development are available. If such databases were to become available in the near future, practical LRFD design criteria could be implemented for civil construction.