By Shari Held
A $350 million donation from the George Kaiser Family Foundation – the largest private gift to a public park in U.S. history – promises to make A Gathering Place for Tulsa one of Oklahoma’s top attractions. Once it’s completed in late 2017, the park is anticipated to draw 1 million people each year.
Designed by New York-based architectural firm Michael Van Valkenburgh Associates, the new park will feature a five-acre playground, lodge, boathouse, pond, sports courts, nature trails, gardens, concert lawns and more.
Crucial to the park’s infrastructure are the new land bridges. They rise 20 feet above the two twin-cell precast concrete traffic tunnels on Riverside Drive, one of Tulsa’s main thoroughfares.
The top of each land bridge will be covered with up to 14 feet of fill that will support trees, landscaping and park structures. This will create a safe and scenic pedestrian park experience while allowing an uninterrupted flow of vehicular traffic below. It’s the perfect balance of practicality and aesthetics.
“The utilization of land bridges is really what makes this park, because it allows people to get down to the Arkansas River safely – something that couldn’t be done before,” said Dan Logel, bridge consultant for the state of New York at Contech Engineered Solutions.
Precast concrete played a major role in making it all happen.
High quality, low cost
Contech worked with the New York City office of infrastructure solutions firm HNTB Corp. to develop a structure that could bear the weight of the fill as well as park structures and landscaping.
The biggest challenge was coming up with a cost-efficient design, and precast was a more cost-effective solution than cast-in-place. Producing cast-in-place elements would have required a new setup for every component. That would not only be more costly, but also more time-consuming.
“By using precast, workers were able to set a component every 30 minutes from the time it arrived on site,” said Ryan Davis, sales and marketing manager for Arrowhead Precast, which produced the components.
Precast also allowed for a higher quality end product.
“With precast, you’re able to do quality control on every load of concrete used,” Logel said. “NPCA certification is one of our standards for becoming part of our producer network. Quality is what we live by and NPCA has provided a forum to evaluate that.”
A logistical challenge
Contech worked with Arrowhead Precast, which it had previously partnered with on local department of transportation and county projects, to produce the precast components for the project.
Overall, Arrowhead Precast produced 5,300 tons of precast to create the 196 CON/SPAN arch units for the two land bridges. Each arch weighs 27 tons and has a span of 42 feet.
“We manufactured and stored the units so that we could quickly ship them,” said Brad Davis, general manager for Arrowhead Precast. “It’s been a great team effort to meet the project’s demanding schedule.”
Arrowhead Precast poured self-consolidating concrete into vertical forms to help eliminate bug holes, honeycombing and other imperfections in the panels. The company produced two precast arch units per day.
“We prefer SCC so we don’t have to use the vibrators to consolidate the concrete around the rebar,” said Cecil Casinger, technical operations manager for Arrowhead Precast. “It flows better and actually speeds up production.”
The biggest challenge for Arrowhead Precast, which is located about 30 minutes from the job site in Broken Arrow, was transporting the components in a timely fashion. Since on-site workers could set a component every 30 minutes, Arrowhead Precast had to preload multiple trucks the night before. Once those were unloaded, they’d return for more.
“Once the site started taking them, we did 24 loads per day,” Casinger said.
A win-win for everyone
Both Contech and Arrowhead Precast are grateful the project used local materials and labor to boost the local economy and that the park will provide a much-needed resource for the community and beyond.
“I take a lot of pride in this project,” Brad said. “Twenty or 30 years from now we’ll be able to look at it and know it was something we were instrumental in creating.”
Shari Held is an Indianapolis, Ind.-based freelance writer who has covered the construction industry for more than 10 years.