Behaviour of GFRP adhesive pipe joints subjected to pressure and axial loadings

The corrosion resistance of glass-fibre reinforced polymers (GFRPs) is a key advantage in pipeline applications. Adhesive bonded joints are often used in tensile resistant GFRP pipe systems and the behaviour of small-diameter GFRP tubular pipe-sections joined by using an adhesive bonded coupler is of interest. In particular, the performance of the joint when subjected to a combination of high tensile axial loads and relatively low internal pressure is investigated. Experiments are conducted where a self-equilibrating pressurisation system is used to control the internal pressure and the coupled sections are tested in tension until failure. The cases of no pressure and a 32 bar working pressure are considered. A preliminary one-dimensional linear-elastic model is developed to predict the behaviour in the early stages of loading and to quantify the influence of internal pressure on the joint performance. Based on the experimental and analytical findings, it is concluded that the most critical case for the joint is likely to be the presence of large tensile loads in absence of internal pressure.