Recently a well-known Texas contractor completed major upgrades to an existing pump lift station. The upgrades were designed to increase the existing sewer capacity and reduce the stress to the nearby force mains during the rainy season. The construction would tie in an 84-inch sewer line to a large-scale wet well. On the opposite end, the line would connect to a new 8-ft manhole and subsequently to an existing force main. The contractor would require a protective device that could secure a pit that measured 84-ft long, 30-ft wide, and 31-ft in depth. In addition, the protective device would need to provide enough clearance for the tie-ins and provide proactive support against the pressure loads originating from the excavation walls. After some calculations, the contractor determined that a site-specific approach would effectively address all of the challenges. Site-specific protective systems have a high degree of customization and adaptability and are normally used on excavations that are kept open for extended periods of time including projects with poor soil and variable conditions.
After contacting NTS, the contractor reviewed a few site-specific options ultimately selecting a cantilever beam & plate system. The cantilever beam and plate system is composed of beams that are inserted through pilot holes while steel plates are pushed to depth between channels within the beams to provide the required lateral protection against the walls of the excavation. The contractor was very impressed with the cantilever beam and plate system capabilities and cost-effective approach.
