A new urban highway can cut through almost any terrain, but a busy railroad crossing its path calls for creative solutions.
By Kent Sipes
The burgeoning town of Blue Springs, Mo. – just down the tracks from Kansas City – had outgrown its old city streets. To handle the increasing population and traffic, a new arterial roadway became a priority. However, the new roadway – the Adams Dairy Parkway – would need to cross the Gateway Western rail line, and that presented a unique challenge because the rail line is a major freight carrier, and its rail traffic could not be delayed for construction.
The city chose to build a new rail bridge over the planned route for the parkway, requiring 3,387 feet of track and several retaining walls to be relocated. There were also critical safety considerations, with workers constantly exposed to busy rail traffic adjacent to the bridge construction site.
Other factors to consider included the fact that the new parkway would have bike paths and sidewalks on each side, as well as a great deal of landscaping. In addition, the bridge had to fit in with the overall concept of the parkway project. After consulting with engineering firm Transystems Corp. of Kansas City, it was determined that precast concrete components would be a good choice for the project.
“We chose precast components for the exterior treatments of the four bridge columns located at the piers because of how easily (precast) could be erected and because of its ability to act as a framework for the interior cast-in-place concrete,” says Mark Shafer, an engineer with Transystems.
The railroad bridge, three simple spans measuring 87 feet long, are constructed of parabolically haunched steel plate girders with a cast-in-place ballasted deck. The girders are complemented by a fabricated tubular steel hand railing on the bridge that is parabolically haunched to mirror the shape of the girders.
The foundations for the bridge are a combination of drilled shafts and driven pile. The substructure received a formliner treatment similar to adjacent cast-in-place concrete retaining walls. The architecture of the bridge and walls is enhanced by the addition of four columns, two at each pier. The 48-foot-tall columns are constructed of precast concrete panels on a cast-in-place concrete base and foundation.
Travelers on the parkway will be greeted with metal artwork inset into each column, accented at night by fiber optic tube lighting that winds its way along the artwork. The precast and cast-in-place components each received the same architectural formliner treatment as the surrounding structures, creating a beautiful structure that is seen as a positive addition to the changing landscape.
The bridge also uses a three-barrel 9 by 12 concrete box culvert for stormwater drainage. “The precast stormwater drainage structure also expedited the project dramatically, compared to the time it would have taken to cast it in place,” says Jeff Sell, Engineering Manager with the City of Blue Springs.
Unexpectedly poor soil strata discovered in the early stages of the project forced the over-excavation of material for the base of the piers. Substructure elements of the bridge also had to be redesigned. This caused the schedule for completion of the project to be extended, but Brian McCrary, a construction manager with contractor GC Construction, says, “The use of precast pier and tower elements cut the construction schedule back immensely.”
According to McCrary, using precast tower elements saved two months. “We would have had to rent scaffolding and hire a railroad flagman for two months, and there would have been many more safety concerns with the crew working adjacent to an active main rail line,” he says. “Of course, there also would have been increased labor costs for the crew, concrete pumping costs, etc.”
McCrary is convinced that precast components are the right choice for products of this type. “Because the pieces fit together perfectly, we were able to erect each tower in four to six hours,” he says.
Of course, the project owner was also very concerned with the aesthetic value of the finished project. “The precast pier and tower elements enabled us to achieve a consistent appearance,” says McCrary. “Colored concrete helped as well.”
Support from the precaster was another important advantage. “The precaster supported the project by delivering high-quality components on schedule, assisting in the design phase, providing high-quality shop drawings and giving field support when needed,” says McCrary.
“I like to use precast components because they speed up the construction project. Also, the final product is of higher quality and requires less maintenance,” adds Sell. “I feel that the quality control of precast concrete is much higher than that of cast-in-place concrete. We have had lots of projects in our city that used precast components, and I’m very happy with the quality they deliver.”
The project began in October 2002 and ended in February 2003. The new bridge blends in with the architecture and landscaping of Adams Dairy Parkway and adds to the beauty of the area. By choosing precast concrete components as an integral part of the new bridge, the city of Blue Springs, Mo., minimized construction delays and provided a structure that met its needs for both form and function.
Project Name: Gateway Western Railroad Bridge
Owner: City of Blue Springs, Mo.
Contractor: GC Construction Co. Inc., Blue Springs, Mo.
Engineer: Transystems Corp., Kansas City
Precast Manufacturer: Barbour Concrete Co., Independence, Mo.*
*Barbour Concrete Co. is a certified plant under NPCA’s Quality Assurance/Plant Certification Program.