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Park above Highway Reconnects Parts of Dallas
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Aerial rendering of the 5.2-acre Klyde Warren Park straddling the Woodall Rodgers Freeway
The 5.2-acre Klyde Warren Park straddles the Woodall Rodgers Freeway through central Dallas, connecting downtown with Uptown. Aerial Photography, Inc.

A multiuse park has been constructed atop a highway that was long ago sunk into a trench, reconnecting downtown Dallas with its up-and-coming arts district.

December 18, 2012—When it opened in 1983, the Woodall Rodgers Freeway cut a path through the center of Dallas, severing the city’s downtown from its developing Uptown neighborhood. But a decision made in 1971—to depress the freeway in a trench rather than build it at grade—ultimately made possible an innovative new park that has stitched part of the city back together.

Last month the city opened the $110-million, three-block Klyde Warren Park, built atop a deck that straddles the freeway. Its boosters are heralding the park as a central gathering space for the city’s adjacent Arts District. Under construction since late 2009, the 5.2-acre park is 1,045 ft long and 210 ft wide. The deck supporting it is 6.5 ft deep.

The project’s roots go back at least 10 years. In 2002, Crescent Real Estate Equities, developers of the nearby Ritz Carlton hotel, hired the Office of James Burnett, a landscape architecture firm based in Houston. At the time Uptown was growing, and land just south of the trench was slowly filling in with an active district replete with museums and theaters.

“They wanted to have a better connection from Uptown to the Arts District,” says the firm’s president, James Burnett, F.ASLA. “So we did a hardhat tour of the Nasher Sculpture Center, walked across the bridge. I remember stopping on a little four-foot-wide sidewalk, and the client saying, ‘This is the big problem: all the noise and this bridge shaking.’ Is there any way of covering this up?”

In 2004, the city’s Real Estate Council commissioned a million-dollar study to find out, hiring Pasadena, California-based Jacobs Engineering Group, Inc., which spent a year on a feasibility study. A year later the Woodall Rodgers Park Foundation was formed to operate and manage the park.

“There was always this desire that we could reconnect Uptown and downtown,” says Mir Ali, P.E., F.ASCE, the engineer of record and Jacobs’s lead structural engineer on the project. “But the issue was who was going to pay for it and who was going to take the lead.”

It turned out to be a nearly even split between the entrepreneurial spirit of Dallas residents (who raised $51 million in private donations), and local, state and federal funds, including $16.7 from the federal stimulus package, $20 million in Dallas city bonds, and $20 million from the Texas Department of Transportation.

The park has raised $108.5 million of its goal of $110 million and is working on creating a “capital reserve.” Since use of the park is free, revenue will be generated from corporate sponsorships, food and beverage sales, and rentals for special events. 

structural-diagram

The park is built atop a deck held up by a system of 300
prestressed box beams. In between the box beams are trenches
formed by concrete panels, which act as planters for the park’s
trees and also convey utility lines. The Office of James Burnett 

After Jacobs’ feasibility study was completed, an international competition was held for a park designer, and ultimately Burnett’s firm won. One of the initial challenges, impacting both the park’s engineering and its aesthetics, was the decision to place the park at the same grade as the surrounding streets. Mark Banta, the president of the park, notes that studies suggest that making pedestrians climb even as few as three steps to enter a park can “tremendously deter people from coming into a green space.”

With the park at grade, engineers didn’t have a whole lot of room to work with, because they had to keep a 16 ft, 6 in. vertical clearance for the vehicles below. As Ali notes in a paper on the project, this required “the selection of the most efficient structural system with minimum structural depth.”

Initially Ali and his team discussed building atop the freeway’s retaining walls, but this was quickly scrapped in favor of building a new deck foundation behind the existing walls, on a drilled shaft foundation. Those new columns, along with a center wall in the middle of the freeway, support a series of 300 prestressed box beams that run perpendicular to the freeway and hold up the deck. The beams were positioned in groups of three or more, Ali noted in his report. Concrete panels connect the beam systems, forming trenches in the spaces between the beams.

The trenches solved a crucial problem: where to plant the park’s trees, which need at least 6 ft of soil in which to grow. The 100 trenches provided enough depth for the trees to take root. Because the trenches are 200 ft long, and only a handful of trees were planted in each one, the remaining space in each trench was filled with 200,000 cu ft of a lightweight geofoam. At 1.88 lb per cu in.—versus 120 lb per cu in. for earth fill—the geofoam reduces the load on the deck by close to 12,000 tons.

Jacobs also laid down a root repellent—a 15 mil thick polyethylene composite geomembrane—in order to keep the roots from penetrating and damaging the structure itself. (Jacobs also laid the utilities through these trench spaces.)

Engineers also had to waterproof the entire deck surface to prevent water from running onto the cars below, and had to meet stringent new fire safety codes while providing ventilation and lighting to the tunnel below. “One of our challenges was that we had to maintain that vertical clearance in the tunnel for the Woodall Rodgers Freeway traffic,” says Deborah F. Neubert, P.E., a senior project manager for Jacobs. “We had to design special low-profile guide signs for use in the tunnel.”

Meanwhile, Burnett and his team of designers were busy with the park above. The goal was to ensure that the park, named Klyde Warren Park, remained accessible, free, and accommodating of a wide variety of uses. “They didn’t want it to be a one-liner; they didn’t want it to be some ego-driven design,” he says. “They wanted it to be something that worked on a lot of levels for a lot of different user groups.”

Rendering of the park which features a portion of the 40,000 sq ft lawn with more than 300 trees

The park features a 40,000 sq ft lawn and more than 300 trees.
Sixty percent of the park will be shaded. Dillon Diers Photography/
The Office of James Burnett

Burnett says the design team spent a great deal of time discussing “a day in the life, a week in the life, a month in the life of the park—how it would break down and support a variety of users.” Input from the community yielded all sorts of ideas, from basketball nets to a tennis court to a skate park. Burnett didn’t want to “overcook” or “overprogram” the space, so it would be “not like a Disney experience, but something that would be timeless.”

Nevertheless, the park packs a lot into its 5.2 acres. It features a children’s area, a performance stage, a caterpillarlike water fountain, a reading area, a walking park, a great lawn, and areas for such table games as Ping-Pong, checkers, and chess. The great lawn is 40,000 sq ft, about a fifth of the park’s total area, and there are 65,000 sq ft of plazas, walkways, and seating areas. Klyde Warren also features a dog park—Burnett notes that because people walk their dogs several times a day, dog walkers provide an effective means of making the park safe at all hours. A restaurant and café are under construction and will open next summer.

“Green” features include solar panels on the light poles, a high-efficiency lighting-management system, and a water reclamation and purification system. The park’s 322 trees may sequester as much as 7 tons of carbon per year at maturity, in addition to mitigating storm-water runoff and urban heat island effects.

Since opening last month, the park has drawn large numbers. “If you had 25 people an acre at all times then it would be safe,” Burnett says. “It would be a positive attraction.” Weekend counts have seen as many as 4,000 people in the park at once, and the opening weekend drew 44,000. “The biggest thing is it takes away the big divide of what was once a big separator of where downtown stopped and Uptown started,” Burnett says. “You would get in your car if you were going to one or the other. Now the connectivity is very strong.”

The park also quiets the noise from Woodall Rodgers, and has slowed traffic on the freeway’s feeder roads. But now that the park is open, it’s already wrestling with challenges brought about by its own success. For starters, the park’s north and south sides are flanked by on-street parallel parking to accommodate visitors arriving by car (there are also some 9,000 spaces in nearby garages). The problem? The meters haven’t actually arrived yet. And the parking spaces have been taken over by a fleet of extremely popular food trucks.

The city is anticipating revenue coming from those meters when they do arrive. But to make matters trickier, the holding tanks, pumps, and mechanical filtration systems for the park’s fountains are located beneath those parking spaces. According to Willis Winters, the assistant director of the city’s Parks and Recreation Department, workers will need to access the systems a couple of times a day for maintenance, making it potentially impractical to have metered parking there.

Winters adds that the park needs 10 times the number of bike racks it currently has. But the biggest issue has to do with a street that bisects the park. Originally, two streets crossed the freeway deck, Harwood and Olive. Park officials managed to convince the city to close down Harwood—there’s no trace of the road in the current park—but Olive remains open, dividing the park into two- and three-acre sections.

Closing Harwood, in the middle of a car-centric metropolis, “took an act of God,” Winters explains. “It took a fundamental paradigm shift in our transportation planners.” Also, such Arts District neighbors as the Dallas Museum of Art and Nasher Sculpture Center were worried about the impact of the closure on visitors reaching their own parking garages.

But now so many people are coming to the park that it’s creating a potential safety issue, Winters says, as pedestrians try to cross Olive. Currently the city is planning to close the street on weekends, but it’s unclear whether the city will permanently close Olive to traffic. “I was in the meeting where we would discuss the weekend closure,” Winters says, “and there was stunned silence” from transportation officials.

Banta adds, “To put it delicately, we have some neighborhood relationship work to do. Anytime you close roads to build a park, there are always traffic engineers who will say we need to leave all the lanes open.”


 

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    "Closing Harwood, in the middle of a car-centric metropolis, “took an act of God,” Winters explains. 'It took a fundamental paradigm shift in our transportation planners.'"
    When the Nasher was first being designed, the plans called for shutting down Harwood between the DMA and the new Nasher facility. That never happened because the transportation planners had the same concerns. Now that Harwood bridge is closed, why keep it open between the museums? It runs the same way as St. Paul, and there is a DMA entrance on the St. Paul side. Why not implement Nasher's original vision, now that there is less reason to keep Harwood open there?

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    Nice capital development by the people for the people. God bless America.

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