Durability evaluation of pultruded GFRP bay window structures

An all-GFRP bay window for residential buildings is developed for energy conservation, low carbon, and comfortable life. The durability performance and design of GFRP bay window in an outdoor environment are investigated experimentally. Relevant studies were first reviewed, and the reported findings were found to significantly vary and could not be directly adopted. To investigate the durability of a GFRP material used in an outdoor environment, four aging tests were conducted, namely, water immersion, wet-dry cycle, freeze-thaw cycle and ultraviolet radiation tests. Visual inspection and scanning electron microscopy were used to evaluate the aging effects on the material. In addition, the weight, Barcol hardness, and tensile and flexural properties of the aged GFRP material were measured after the aging tests. Water immersion had the greatest effect on the mechanical properties of the GFRP material, while the freeze–thaw cycle had a negligible influence. Furthermore, to assist in the design of an all-GFRP bay window with a service life of 50 years, a design method was proposed based on the experimental results obtained in this work. This method is the first to directly support the practical design of the long-term behavior of GFRP structures in China and has great potential to be widely adopted in the future.