Structural performance of damaged rigid pipe rehabilitated by centrifugal spray on mortar liner

Abstract

There has been growing interest in using trenchless technology, especially centrifugal spraying techniques, to renovate the sewer pipe network in China. In this study, a damaged reinforced concrete pipe (RCP) (i.e., 14.7% vertical deformation) with one-meter diameter is rehabilitated by centrifugally spraying on a 50 mm thickness mortar lining. The ultimate (Du) D-load only increased by 2% compared to host pipe’s residual strength; however, other pipe properties exhibited improvement. Based on the behavior of two experimental results, finite element models were established, and an innovative pipeline damage quantization model was proposed. Through parameter sensitivity analysis, the effects of interface strength and fracture energy on pipe bearing capacity were studied. It was discovered that interface bonding performance affected the service load of the rehabilitated pipe. From the analysis of pipeline initial state deformation influence on the repaired structure bearing capacity, it was discovered that selecting a reasonable repair time point can effectively improve the functionality of the pipe network and reduce repair costs. An analysis of RCPs structural repair with a vertical deformation larger than 14% revealed that it is difficult to repair damaged pipes only employing mortar spraying. A structural design method based on the service load and ultimate load is presented in this paper.