Raleigh Water Upsizes 8-inch Gravity Sewer to 12-inch Via Pipe Bursting

Abstract

Raleigh Water, North Carolina, experienced a sewer main break on their 8-inch concrete pipe gravity sewer located in a major thoroughfare. This case study will examine the process of upsizing that 8-inch concrete pipe gravity sewer to 12-inch High Density Polyethylene Pipe (HDPE) via pipe bursting along a major city street that is also within an NC Railroad right-ofway. The railroad typically doesn’t allow plastic pipes in their right-of-way without metallic pipe encasement. Topics discussed in this case study will be coordination with the railroad concerning pipe replacement material, coordination with the North Carolina Department of Transportation concerning asphalt mill and overlay requirements and traffic control requirements to accommodate work and lay down areas, and the bypassing requirements including accommodations for side streets and driveways. Lessons learned will cover the placement of launching and receiving pits, decisions to either replace or rehabilitate the manholes, benefits of adding new manholes to aid in pipe bursting operations and traffic control measures, and lateral replacement methods.