The pedestrian SkyDance Bridge was to be an "iconic symbol of Oklahoma City's future," according to city planners, spanning the relocated Interstate 40 near S.W. 9th Street and Harvey Avenue and providing a critical link between the city's core and development to the south.
But when the bridge's projected construction costs more than doubled from initial estimates, designers were told to go back to the drawing board.
The SkyDance Bridge, unveiled in 2008 after a city-sponsored international competition in which 16 design firms vied for the job, is certainly an attention-grabber.
Intending to capture the "sky dance" of the scissor-tailed flycatcher, the bridge was designed to be 30 feet wide and 440 feet long, crossing the semi-depressed section of the realigned Interstate 40 and the Burlington Northern-Santa Fe Railroad on the southern edge of downtown.
The tallest wing of the bird was to tower 185 feet above the interstate, glowing from within at night via translucent material on the structure's face and lighting from below.
Anchored to the wings were to be cables, providing tension and playing a vital role in supporting the bridge, known as a cable-stay structure.
When the SkyDance model was presented by MKEC Engineering and Butzer Design Partnership, the bridge's estimated cost was around $5.2 million to complete. Principal Hans Butzer, who declined to comment for this story by press time, was part of the design team for the Oklahoma City National Memorial.
The bridge's price tag eventually went up to $12.8 million, far beyond the city's $6.8 million budget.
Now, the city will get a bridge that looks much the same, but rather than a cable-stay structure, it will be a truss bridge with a sculpture of the bird still intact.
Several reasons caused the ballooning cost of the bridge.
One of the major sources of projected cost overruns, according to a city council memo, arose because the bridge model and cost estimate were presented based on design requirements now rendered obsolete. In addition, new requirements recommended by the Oklahoma Department of Transportation, which was brought into the design process as a third-party design reviewer, required the bridge to support a much heavier load capacity.
The new pedestrian bridge guidelines took effect in December 2009, said Brenda Perry, spokeswoman for ODOT.
"As soon as we became aware of it, we contacted the city about it," Perry said.
Dennis Clowers, public works director and city engineer, said the concerns were "legitimate."
Another source of cost increases was an unexpected "Buy American" clause in the contract that developers were unsuccessful in having ODOT waive. The clause requires many construction materials to be purchased from U.S. companies, and added significant expense to the project, the city council memo states.
A third reason for the increases came after the bridge had to be realigned further away from the historic Union Station, the memo states.
"It blew up by 100 percent, just unacceptable," said City Manager Jim Couch.
Couch said he proposed making the bridge a truss-supported structure but with the cables on the towers included " a sort of faux cable-stay bridge " but designers said it would be intellectually dishonest to do so, and came back with a second design featuring the truss pedestrian bridge with the self-supported bird sculpture included.
"It's the same thing sans the cables," Couch said. "We're trying to maintain the functionality of the pedestrian bridge, we're trying to have this iconic art piece and we're trying to bring it under budget. I think we're close to getting there without violating any of the principles. Did we compromise? Yes. Was it exactly what it was supposed to be? No, it's not. But again, I don't think most people are going to know the difference going by. I think most people are going to say 'that's really something' when they go by."
In addition, a second bridge north of the SkyDance in the first set of plans will be listed designed as an "add-alternate," which means that it will be built only if the company winning the construction bid can include it for under the total bid amount, Clowers said.
If the north bridge cannot be constructed, a ramp will be put in instead, the council memo states.
Uniquely designed bridges can often become costly endeavors, said Kevin Womack, a professor of civil engineering at Utah State University and a director at the American Society of Civil Engineers.
"When you can get everything to work out, it's terrific," Womack said. "But oftentimes " like you're running into here " it doesn't always work out because some fly may end up in the ointment, and in this case it's cost. The more complicated it is, the more expensive it is to construct. So now they (the city and designers) are falling back on a tried-and-true type thing, which is a truss bridge, which we all know how to engineer. It's simple, it's less expensive to construct. Then they'll add the architectural details to make it look different."
According to the city council memo, the bridge now has an estimated construction cost of $6.8 million, an amount that puts the project right against its budget threshold.
"The construction budget for this project is very tight," the city council memo states. "Extraordinary design effort will be required to meet this construction budget."
The memo goes on to state that inflation and material cost changes were not included in the $6.8 million estimate.
Clowers said the project will likely begin and be completed next year, so inflation or other cost changes may not be much of a factor.
"From what we can tell, that's not going to be the case," Clowers said of possible future cost overruns. "If it is, we have to find additional funds or will have to change the design of the bridge again."
On Oct. 26, the city council unanimously passed a measure on its consent docket (which allows the council to vote on several items at once) to pay an additional $179,984 to designers to change the planned bridge, putting total design costs around $1.6 million.
There was no public discussion by the council on the measure or the bridge.
See a related SkyDance Bridge presentation video.
above This older rendering shows the SkyDance Bridge while driving west on the relocated Interstate 40. The newer version won't have cables.