Braddock Dam Lock #2, Pennsylvania

Photo: BCG / COWI
Precast concrete dam segment floats to the project site on the Monongahela River.
COWI MARINE North America working with the Pittsburgh District, USACE designed and assisted with construction supervision of the New Braddock Dam.

COWI MARINE North America took the lead in designing the float-in precast dam segments and developing "In-the-Wet" construction methods and procedures.

This innovative design not only led to a substantial savings in cost and construction time, but also minimized the effect on river traffic during construction, substantially reducing or eliminating the impact on the navigation during rehabilitation.

Offshore technologies

COWI MARINE North America utilized the offshore technologies to the inland waterway structures, and forever changed the ways that locks and dams will be constructed.

Main design features:

  • Conceptual design of the cast and launch system for the precast dam segments
  • Transport, positioning and immersion of the segments on to pre-installed foundations
  • Developing a cast and launch facility for two 11,000 ton dam segments
  • Designing a 333 ft long precast shell with sufficient strength for launch, transport and immersion while maintaining a ten ft maximum draft
  • Developing a transport, positioning, immersion and dam completion plan that can safely accommodate a 500- year flood on 48 hour notice
  • Developing a positioning system with +/- ¼ inch vertical and +/- two inch horizontal tolerances
  • Drilled pier foundation layout and preliminary design
  • Underbase grouting and tremie in-fill concrete plans
  • Risk analysis of the segment, launch, transport outfitting and installation

LAST UPDATED: 07.02.2017