From Argentina to Vietnam, 350 representatives from 39 countries gathered in Zaragoza, Spain in late October to discuss dams, and included in the discussion was Jacksonville District’s Portugues Dam.
The meeting was billed as the Sixth International Symposium on Roller Compacted Concrete (RCC) Dams. Three representatives of Jacksonville District spoke at the event: Portugues Dam Project Manager Alberto Gonzalez, Portugues Dam Resident Engineer Pablo Vázquez-Ruiz and Portugues Dam Project Geologist John Conway.
“The symposium was a great experience,” said Conway. “It provided a worldwide view into the RCC construction industry of the past, present and future.”
The trio shared their stories and experiences regarding foundation treatment of the dam, and the transition in design from a conventional concrete dam to a RCC dam.
“We talked about how the shift to RCC construction technology was the key element to be successful in delivering a much-needed flood reduction solution for the citizens of Ponce [Puerto Rico],” said Vázquez-Ruiz.
RCC has the same basic ingredients as conventional concrete: cement, water and aggregates, such as gravel or crushed stone. However, unlike conventional concrete, it's a drier mix, stiff enough to be compacted by vibratory rollers.
“It was very interesting to see how less-developed countries have utilized the RCC technology with modifications based on scarce resources and remote construction sites,” said Vázquez-Ruiz. “Despite those limitations, those countries have succeeded in delivering economically effective solutions based on the RCC technology.”
“Portugues Dam is unique in that it is a thick arch RCC dam; the first in U.S. territory,” added Vázquez-Ruiz. “There are only about 10 to 12 thick arch RCC dams in other parts of the world.”
The U.S. Army Corps of Engineers has a long history with RCC dams, pioneering the concept in 1981 with Willow Creek (Ore.) Dam. While controversial at the time, Willow Creek Dam was credited with preventing major damage to nearby Heppner, Ore. during heavy rain events in the spring of 2011.
“The concept has now been applied to 500 dams worldwide,” said Gonzalez.
Construction on the dam is expected to be finished in September 2013. Crews finished RCC installation this spring, and have spent most of the summer completing a grouting procedure and working on numerous other features.
“They are now working on the access road,” said Gonzalez. “The valve house is finished, but work remains on the pipes that will carry water through the dam.”
Additionally, Jacksonville District engineers are working on plans to turn the dam over to authorities in Puerto Rico after the first year of operation is complete. This “turnover plan” includes references, training and a schedule for making it all happen.
“As construction is completed and components of the dam become available, we will conduct tests on everything to ensure it works,” said Luis Alejandro, civil engineer in the water management section. “We want to turn over a quality product.”
The Portugues Dam presentations were well-received at the conference.
“It was an honor to represent the Corps,” said Gonzalez. “I looked up on our slide, and saw our red and white castle, and was filled with a tremendous sense of pride standing in front of an international audience.”
Once complete, the dam will protect Ponce, a city of 190,000 people along the southern shore of Puerto Rico. It is the final piece of the long-awaited Portugues and Bucana flood risk reduction project.
Earlier in his career, Alejandro worked on Cerrillos Dam, northeast of Ponce, another component of the project.
“Seeing this all come together is very gratifying; it’s like tying the final ribbon,” said Alejandro.