The Jacksonville District’s Portugués Dam Project Team has won the USACE Dam Safety Team Award of Excellence for 2015.
The team brought together experts from across the Corps, as well from the private sector, to design, review and build the thick-arch roller-compacted-concrete dam.
“We had many members on the project delivery team, who rotated in and out as their expertise was required during different phases of the project” said project manager Alberto Gonzalez. “What united us was a common desire to work together and deliver the project.”
Portugués Dam is the final piece of the Portugués and Bucana flood risk management project, which reduces the effects of flooding in Ponce from the Portugués and Bucana Rivers. The finished dam is 220 feet high, 1,230 feet long at the crest, and required 350,000 cubic yards of roller-compacted concrete. Total cost of the project is $375 million.
“Roller-compacted concrete is a relatively new method of building with concrete, developed in the 1960s. It allows concrete to be delivered at high rates by conveyors or large trucks, spread with bulldozers and compacted with rollers, so large volumes (like, for instance, those associated with a dam) to be placed at a lower per cubic yard cost. Roller-compacted concrete also has lower costs associated with post-cooling and formwork,” said Chad Gillan, a structural engineer with the district, who worked on the project.
The team employed multiple innovations to design and construct the dam, including:
- “Duration grouting” (grout mix with microfine cement injected at low pressures for longer times to penetrate tight joints),
- Arch dam software tools (including USACE Arch Dam Design Manual), and design criteria which led to the roller-compacted concrete thick-arch design,
- Photogrammetric mapping for the foundation, which used computer-processed photographs to identify strikes, dips, and geologic features, dramatically reducing the cost and time required to map the foundation.
To keep concrete temperatures down in acceptable ranges, the team used a chilled water tunnel to cool the coarse aggregate and an ice flake plant to chill the concrete during placement.
More information about Portugués Dam is available at: http://www.saj.usace.army.mil/Missions/CivilWorks/FloodControl/PortuguesDam.aspx.