Structural performance of sliplined watermain

Rehabilitation of a watermain by grouted sliplining is usually carried out when the existing pipe is only partially deteriorated. Although designs that neglect the structural contributions from the existing pipe and the grout are generally conservative, the performance of the rehabilitated pipe needs to be better understood for effective design and management of buried water pipes. Presented in this paper is a practical method for the determination of load sharing and circumferential stresses in a sliplined pressure pipe. The laboratory tests show that the load carrying capacity of a cast iron pipe increases substantially after it is sliplined and grouted. Results also indicate that the eccentricity between the host pipe and the inserted pipe and the direction of eccentricity have an impact on the rupture load of the sliplined pipe. The effects of the host pipe wall thickness and the grout strength are also discussed. Although the method is based on a pressurized watermain, it can be used to assess the load carrying capacity of a non-pressurized pipe such as a sewer pipe. The use of this method is demonstrated through an example.Key words: performance, sliplining, watermain, circumferential stress, load sharing, grout, service life.