Effect of Natural Weathering on Durability of Pultruded Glass Fiber–Reinforced Bridge and Building Structures

Abstract

After 17 and 15 years of use, respectively, a detailed inspection of a pedestrian bridge and a 5-story building structure composed of partly adhesively bonded pultruded glass fiber–reinforced polymer (GFRP) profiles was conducted accompanied by full-scale serviceability and destructive coupon testing on exchangeable profiles. The bridge is exposed to a harsh Alpine climate and the building to a mild plateau climate. The system and material stiffness of the bridge remained unchanged during the 17 years. The material strength of the bridge, however, was significantly affected by combined freeze-thaw cycles and ultraviolet (UV) irradiation. The latter accelerated the strength degradation by uncovering the fibers (fiber blooming) and thus inducing humidity ingress into the material by wicking effects. A large majority of the small-area adhesive bonds in the bridge were intact, although a few small cracks were observed in some joints at the surface. The large-area bonds of the building did not show any damage. Based on results of the inspection of the bridge, the application of an appropriate coating on pultruded GFRP structures exposed to harsh environments is recommended.