Charleroi Locks & Dam
Location: Monongahela, PA
Owner: US Army Corps of Engineers, Pittsburgh District
General Contractor: Trumbull-Brayman, Joint Venture
Value: $96.5 Million
Date Complete: May 2011
This project, located at the Charleroi Locks and Dam on the Monongahela River, consisted of the construction of a new river wall for a future lock chamber. The work included a significant amount of “in - the - wet” construction techniques for drilled shafts and concrete placements. Part of the contract required the team to design and provide a state of the art concrete batch plant, as well as develop a large dredge material disposal site for this and future USACE contracts. There were 144 drilled shafts on the project; 30 at 54in diameter and 114 at 78in diameter.
All concrete placements for the caissons were performed using underwater tremie placement techniques. The maximum concrete lifts were 15ft and individually required three lifts. The top of each lift had to be cleaned by the diving team, prior to placement. There were 21 new monoliths constructed which demanded the construction of large coffer boxes, dredging and concrete placements. A total of 47 underwater tremie placements and 106 mass concrete pours were completed. The team furnished and installed a 2,000lf conveyor system to supply concrete to the monolith and caisson concrete placements. In all, the project placed over 70,000cy.
The project included 14 rock anchors installed underwater with an innovative above-water approach. Our approach minimized diver utilization and allowed the team to overcome artesian conditions for a successful anchor installation.
Additional features on the project included de-watering, sheet pile installation, and the fabrication and installation of custom large fill/emptying valves with mechanical embeds. For those monoliths, which did not require dewatering, sheet piling (cut off wall) was driven and cut to grade prior to the first lift of mass concrete placement. This work was accomplished utilizing floating plants and divers. Full depth forms and the tremie placement method were then utilized for the underwater mass lifts.