The cantilever setting used required one of the largest cranes in Texas (shipped on roughly 60 trailer truckloads), with a 900-ton capacity.

"They used that crane to set these in place, then they post-tensioned them, and because they were sitting on a cantilever, they post-tensioned them after they were set, then they grouted and finished the process," says McKay. "This was a pretty unique approach. It gave them a competitive advantage not only in the construction but also in the proposal process."

Medina pointed out that, at the time, this type of application had not been introduced in Texas. "The design-build process and DART's willingness to allow us to be innovative challenged the team and it produces good results for the client," Medina says.


Sustainability and Outreach

Staying green is a growing priority for transportation entities today. DART has already embraced sustainability, obtaining about 15% of its power for the light rail system from renewable sources such as wind and converting its bus fleet to run on natural gas.

"We've also done a pilot program over the last five or six years on composite railroad ties," which are made of recycled materials, McKay says. With consistency in quality improving, these ties are being used on DART's commuter rail line and on the Trinity Railway Express and are being tested on the light rail lines.

DART has used incentive programs as part of the design-build process, such as for early completion. But the agency is also focused on safety and diversity. All workers on DART projects must complete six hours of OSHA safety training along with mandated background checks and drug screenings.

Almost 15,000 workers on the Green, Orange and Blue Lines went through this program, enabling DART to finish these projects at about 1/10 of the national average in dollars paid for workers' compensation costs based on man-hours worked, says DART's McKay.

"We're also very proud of our minority, women and disadvantaged business [contracting] program," says Thomas, DART president. "We have a very aggressive program, typically around 40%." On the Blue Line extension, the DBE goal was at 42%, but Austin Bridge managed to raise the figure to 54%.

"We ended up having 71 different subcontractors on the project, and for an infrastructure-heavy civil type of project, that's a real different way of doing the project," says Austin Bridge's Stubblefield. "Diversity was a big part of it, but it also helped us manage the project and build it a little bit faster by having multiple resources in there."

With the future in mind, DART lives by a 20-year financial and growth plan that tells the agency what it's building, when work will occur and where funding will be sourced. The 2030 Plan is currently being updated to address some of the economic challenges of the past several years.

"Making sure you maintain what you've built is a hot button issue and is getting harder for some transportation organizations, certainly as revenue sources start to shrink," Thomas points out. "We obviously have a lot invested in our capital infrastructure, and we intend to keep it in a state of good repair and make sure that we can continue to do the things that we're doing today to serve the transportation needs of folks in North Texas."