The Cross Street Bridge is an infrastructure wonder and it's a project that will serve as an inspiration and an example to many others desiring to integrate infrastructure improvements into the community. The three-span Cross Street Bridge is the first major design-build transportation project in the state of Vermont.
Longest Precast Splice Girder Bridge Under Construction in New England
The town of Middlebury, VT held a groundbreaking ceremony near the site of the new Cross Street Bridge on Tuesday, April 14, 2009. The new bridge, which was designed to improve traffic and safety, will link Main Street with Court Street across the Otter Creek via Cross Street. According to the members of the design-build team, the new bridge includes two piers and three spans, including one span of 240 ft and two spans of 120 ft, with abutments and retaining walls at each end that will be buttressed by a series of prestressed concrete girders. Designed to be low-maintenance, the concrete bridge features an eight-inch thick concrete deck with three inches of pavement, eleven-inch thick, six-ft-wide sidewalks with architectural features and lighting. In addition, a corrosion inhibitor was used in the precast concrete fabrication. Epoxy-coated reinforcement was used in the deck, along with a membrane and pavement wearing surface.
Each approach span consists of ten 42-inch-deep x 4-ft-wide x 120-ft-long box beams with one utility bay. The center span is made of five NEBT (New England bulb tee) girders 3000mm x 240 ft clear span spliced girders with a modified 10-inch thick web. Each girder line is comprised of two 65 ft end segments and one 108 ft center segment with 2 ft wide splice joints. Each girder has five 4-inch diameter P/T ducts, three with (22) 0.6-inch strands and two with (19) 0.6-inch strands. Box beams weight was 127,000 lbs with the end segments weighing 133,000 lbs and center segments weighing 185,000 lbs.
Design-Build Process and Team
To maximize the cost-effectiveness of the Design-Build process, the bridge will be constructed using local materials, supplied by local companies. The precaster J.P. Carrara & Sons, was required to produce a 10,000 psi self-consolidating concrete to meet the bridge design needs. Through close coordination with regional admixture representatives and a thorough quality control program, a consistent concrete was produced that met or exceeded the design requirements. Middlebury's bridge design-build team consists of Kubricky Construction Corp., GeoDesign Inc., J.P. Carrara & Sons, VHB Pioneer, and the Town of Middlebury. The four firms have a presence in the region and J.P. Carrara & Sons, is based in Middlebury.
Estimated to take 19 months to build, the bridge includes 11-ft-wide travel lanes bordered by four-ft-wide shoulders. It also includes extensive roadway improvements, and will be financed by a local option tax of one percent on sales combined with 30 years of bond payments made by Middlebury College. No state or federal money is supporting the project.
Bridge Opens One Month Early
The bridge was completed and open to the public on October 2010.
Cross Street Bridge
J.P. Carrarra & Sons,
VHB Pioneer and the Town of Middlebury
• (5) Clear span spliced NEBT (New England bulb-tee) girders: 3000 mm x 240 ft x 120 ft with a 10-inch-thick web
• Box beams: 127,000 lbs
• End segments: 133,000 lbs
• Center segments: 185,000 lbs