The good corrosion resistance and strength of glass reinforced epoxy pipework has led to increasing uses in the nuclear, chemical and other industries. The majority of those uses involves internal pressure and axial loading. Efforts are still needed to improve the understanding of the mechanical conditions of damage initiation and its evolution for different winding angles. This is equivalent to the case where hoop-to-axial stress ratio varies for a composite of given winding angle. The most likely damage initiation sites are the fiber-matrix interface and the microstructural defects. The determination of local mechanical conditions depends on the knowledge of the local stress field and the interface strength that is poorly known. For the first, we need a micromechanical modeling and a macro-micro rescaling indirectly for the second.