Structural Rehabilitation of Ovoid Brick Sewers in Mumbai, India

摘要

Mumbai ( erstwhile Bombay) has been the pioneering Indian city to use new technologies and methods tornbuild and upgrade its public infrastructure facilities. The Municipal Corporation of Greater Mumbai (MCGM),rnthe city government, which is responsible for providing public sanitation facilities for the city’s 12 millionrnresidents, is adopting trenchless rehabilitation technologies to rehabilitate and renew about 15km ofrncentury old brick masonry ovoid sewers and about 2 km of circular sewers, built beneath many of the city’srncongested and narrow streets. The cost of rehabilitation work is about US$35 million and is financed byrnMCGM from the proceeds of the World Bank assisted Bombay Sewage Disposal Project. Four rehabilitationrncontracts are currently under execution. The paper discusses Mumbai’s choice and experience in the use ofrnGRP ( Glass fibre Reinforced Plastic) liner pipes for the trenchless rehabilitation of circular and ovoidrnbrick sewers. The state-of-the-art reaming technology is being used in the project by a contractor tornenlarge the sizes of the brick sewer. India is the second country to use the reaming technology tornminimise the loss of sewer cross sectional area. The paper discusses the contractor’s choice to use thernreaming technology in which a computer aided reaming machine is used to ream the sewer beforerninstalling GRP liner pipes. The GRP liner pipes are designed as structural liners to withstand all soil, trafficrnand hydraulic loadings. Both Type I (composite) and Type II (standalone) design techniques have beenrnadopted by the contractors to design the GRP liner pipes. The paper discusses briefly the designs adoptedrnand the incorporation of abrasion resistance layer and corrosion barrier in the GRP liner pipes. The GRPrnliner pipes are locally manufactured by the contractors.