Seismic Analysis of Rehabilitated Buried Segmented Pipes Using CIPP Trenchless Technology

The recent developments of analytical and experimental tests for underground pipelines rehabilitation are presented. The finite element simulation results appear to give reasonable estimates for encased liner buckling pressure tests. Despite its simplicity, the finite element model outperforms all analytical methods. This work shows that further analytical, field, and/or laboratory studies and finite element analyses are required in order to fully understand the host pipe-liner interaction behaviour and to determine the related applicability of liners design under different conditions of pipe deteriorations, liner geometry, and various pipe materials. The development of better analytical formula does not seem to be possible with the existing tests, which have shown significant variability.;Further, the current study develops a tool to use numerical simulation results of joint behaviour for seismic analysis of buried segmented pipeline networks including axial and transverse permanent ground deformation investigations. The developed numerical models are used for the seismic analysis of typical rigid segmented pipelines. Failure analysis of the segmented pipeline is achieved in order to determine the potential of the pipeline joints for damage and failure under seismic effects.;Finally, this work also explores the numerical modeling of delamination of rehabilitated segmented buried pipelines using a cured-in-place technique. Two finite element analyses procedures considering friction effects in the contact boundary between the host pipe and the liner are proposed to predict the axial/flexural behaviour of the unrestrained joint and the delamination in rehabilitated segmented pipeline under external quasi-static loads or seismic effects. It is found that the encased liner is debonded or delaminated at the joint region resulting in a decrease in the rigidity of the joint when the axial and flexural loads are increased. A parametric study is carried out to investigate the influence of the host pipe material, liner material, liner thickness, pipe stiffness, and interface condition on the seismic behaviours of buried rehabilitated segmented pipelines. The results of effects of the liner thickness on the seismic responses of buried rehabilitated segmented pipelines indicate that the liner strain is a decreasing function of the liner.;This work also describes the numerical modeling of the axial compression and bending behaviours of segmented pipe joints using the finite element method. The results of published full-scale tests by others (Bouabid, 1993 and Singhal, 1984) of unrestrained joints for typical rigid pipes were used to validate and calibrate the finite element models. The research develops a tool to use numerical simulation results of joint behaviour for seismic analysis of buried segmented pipeline networks subjected to axial and transverse permanent ground deformations. These numerical simulation models are verified using the available analytical and numerical models for longitudinal permanent ground deformation (Selventhiran, 2002) and transverse permanent ground deformation (Liu and O'Rourke, 1997).