Stability of loosely fitted liners used to rehabilitate rigid pipes

Lining of rigid pipelines has emerged as a competitive alternative solution to conventional pipeline replacement. Due to the nature of the liner installation process, the final liner may end up being loosely fitted into the damaged pipeline. The liner should safely carry any external pressure due to the ground water. This study considers the effect of an initial gap between the circular liner and the circular host pipe on the critical buckling pressure. The finite-element method is used for the evaluation of the critical pressure for loosely fitted circular liners. The interface between the circular liner and the host pipes is assumed to be smooth. A brief description of the finite-element model and the analysis is given, followed by a parametric study for the effect of gap size and liner thickness-to-radius ratio on the stability of the liner. The results of this study are reported in a form suitable for design purposes. The work includes comparisons between the writers' numerical solution and previous theoretical solutions and experimental work.