Manhattan, KS - U.S.A.

The baseline contract, approximately 50 Million dollars, comprised constructing a jet grouting cutoff wall on the upstream toe of the dam and providing pre-construction services to support developing the final design of the soil stabilization, which will reinforce the potentially liquefiable foundation soils and prevent large displacements of the dam from occurring as a result of an earthquake. The baseline contract included four options to be negotiated during the construction of the cutoff wall. One the options awarded was the execution of a large field test (Test Program Option), approximately 4 Million dollars in value, where Jet Grouting, double and triple fluid, Soil Mixing and slurry wall technologies were tested.
From the outcome of this field test and the preconstruction services provided by Treviicos South, the USACE completely re-designed the downstream stabilization selecting the use of the slurry wall technology to build some 350 self hardening cement bentonite walls, 45 ft long, 4 ft wide and 70 ft deep, that were installed perpendicular to the axis of the dam.

The downstream soil stabilization, known as Main Construction, was awarded to Treviicos South as a Construction Manager at Risk type contract, which includes apart from the cement bentonite walls, the construction of a working platform, the restoration of the downstream embankment and the overlay of riprap on part of the upstream face of the dam. The contract amount is $ 125 Million dollars and the total project duration around 5 years.
This has been a very successful project for both the USACE and Treviicos South, because as a result of the partnering effort carried out it was possible to reduce the overall project cost and completion time in half of the original Government’s estimations. The project has run four years without any loss time accident, some 370,000 hours, obtaining the USACE Large Constructor Safety Saves Award two years in a row.