Seismic Performance Evaluation of Buried Pipelines Retrofitted with Cured-in-Place Pipe Liner Technology under Near-Fault Ground Motions

Seismic vulnerability of buried pipelines has been identified in many post-earthquake reconnaissance reports. Efficient retrofit of critical lifelines to improve their seismic performance becomes an urgent requirement nowadays. The cured in place pipe (CIPP) liner technology is an effective trenchless method for repairing existing underground lifelines with minimal ground surface disruption. However, the seismic performance of CIPP liner-reinforced pipelines is lacking verification and quantification. This paper presents and discusses the results of full-scale quasi-static and seismic tests conducted on water-pressurized ductile iron (DI) pipelines reinforced with one type of CIPP. The axial behavior of the liner-strengthened DI pipelines under static cyclic loading and their seismic response under transient ground deformations (TGD) during earthquakes has been investigated in this paper. Moreover, numerical models have been developed to simulate the axial behavior of liner-reinforced joints under cyclic loading. The results indicate that CIPP liner substantially increases the longitudinal stiffness and strength of the joints of segmental DI pipelines and significantly improves their seismic behavior under high intensity TGD.