Predicting Functional Failure Pressures in Filament Wound GRP Mortar Pipes

Thanks to light weight, high corrosion resistance, non-toxicity, low internal friction, longer services life and low thermal and electrical conductivity, Glass fiber Reinforced Polyester (GRP) pipes are utilized in a wide range of applications such as water supply, waste water transmission, drainage, irrigation network and power plants. GRP pipe producers most often have to design thicker walls in pipe constructions to increase the stiffness of the pipe against external transverse loading especially for buried pipe applications. A simple and cost-effective way for increasing the wall thickness is to use impregnated filler layer between FRPs plies instead of improving thickness solely by FRP layers. The aim of this paper is to investigate damage mechanism of GRP pipes having a sand core layer subjected to internal pressure. In this regard, a parametric progressive damage modeling is developed in ANSYS commercial. The influence of core thickness on first-ply pressure and functional failure pressure (at which weepage occurs) is then studied. To validate developed modeling, the results obtained from theoretical modeling are compared with experimental results from hydrostatic tests and a good agreement is observed.