Beneath the streets of the City of Pittsburgh, Pennsylvania there is an intricate network of aging sewers. Built in the early part of the 20th Century, many of these conduits are built of brick, which has tended to deteriorate and disintegrate over time.
Pittsburgh Water and Sewer Authority (PWSA), the authority that oversees wastewater operations in the city, needed assistance in stabilizing several sewers that ranged in size from 46 inches to 10 feet in diameter. These pipes were located between 20 and 40 feet below street level.
The project involved:
- Cleaning dirt and debris out of the sewers targeted for stabilization
- Diverting storm water and raw sewage away from the work areas
- Monitoring the worksite for hazardous gases
- Removing loose bricks
- Installing steel rods in the ceilings and walls of the tunnels for stability
- Installing galvanized mesh around the circumference of the tunnels
- Spraying a two-inch coating of shotcrete over the mesh
- Wet & Dry Shotcrete
- Water Control Injections
- Water Cleaning
- Pressure Washing
- Masonry Cleaning