Rehabilitation Honorable Mentions
Capital Circle 36-in. Force Main Pipe Bursting Repair Pilot
In August 2008, the City of Tallahassee, Fla., experienced extensive rainfall as a result of tropical storm Fay. The heavy rain caused three pipe breaks in the city’s Capital Circle Roadway Force Main. Since the roadway is one of the busiest routes, the City of Tallahassee contracted MWH to evaluate the damage and examine trenchless repair options. Pipe bursting was selected, especially to maintain the current flow capacity of the existing force main. From there, MWH engineers designed a pipe bursting pilot for a 280-ft section of a 36-in. diameter HOBAS force main, replacing it with 36-in. PE4710 pipe. In order to effectively and quickly repair the damage, the city divided the repair into three separate projects. On average, two pipe bursting setups were completed for each week, resulting in an average of 830 ft of new pipe installed per week. Construction on the project was completed in February 2010.
Project Owner: City of Tallahassee, Fla.
Contractor: Portland Utilities Construction Co., Solomon Construction and Allen’s Excavation
Westlake Sanitary Interceptor Treatment Project
After a condition assessment of its sanitary interceptor, the City of Westlake, Ohio, discovered that various sections of pipe had corroded because of hydrogen sulfide. If not treated, this corrosion could lead to structural failure of the pipe. In order to prevent this from happening, the city decided to perform the rehabilitation by using a spray-applied cementitious coating with an antimicrobial agent called ConShield, which is manufactured by AP/M Permaform. By using a process known as centrifugally cast concrete pipe (CCCP), the coating was applied on the surface of the prepared pipe by a spin caster at a thickness of a ½ in. The spin caster was pulled at a uniform rate and applied the cementitious coating 360 degrees around the circumference of the pipe with compressed air. Using the pumped cementitious coating, the City of Westlake rehabilitated 3,961 lf of pipe and saved around $1.5 million over other rehab options.