By Julia Purdy
The geometry of the bridge contrasts with Otter Creek’s natural environment.
On Monday, June 20, drivers waiting at the light at West Street and Route 7 in Rutland were forced to make room for a 100-foot flatbed truck, escorted by police, bringing fully-assembled components of the Ripley Bridge from Casco Bay, Maine. As the tractor rounded the corner to head west on West Street, drivers realized they were going to have back up—and by more than just a few feet. The long body of the trailer edged around the turn without incident but made quite a spectacle nonetheless.
Over two days, seven similar loads were delivered.
Steel beams and two pairs of steel trusses, 113 feet and 92 feet, respectively, were destined for the site of the new Ripley Bridge on Otter Creek in Center Rutland. The beams were then anchored to a new concrete pier set in the middle of Otter Creek to support the deck, a sidewalk and pony trusses—half-height side walls made of riveted girders.
The pony truss bridge was requested by the Vermont Division of Historic Preservation to correspond to the design of the old green iron bridge, which will be taken down. A “pony truss” bridge is open at the top. The existing pony truss bridge dates to 1928; it replaced the covered bridge that was swept away in the Flood of 1927. As it became unsafe, a Bailey bridge—a temporary bridge developed during World War II—was put over it.
As for the two old bridges, “We’ll cut them up and throw them in the truck,” said Roger Slater, project foreman with Kubricky Construction, Saratoga, N.Y. The abutments will be left in place to stabilize the riverbank, the supporting pier will be taken out, and the approaches will be seeded with grass, he added.
The site has local historical importance. Marble mills dominated this stretch of Otter Creek. The river crossing was named Ripley after the owners of a marble mill, brothers who were also decorated Civil War veterans. Edward Hastings Ripley, as brevet brigadier general, led the Union Army’s occupation of Richmond, Virginia, in 1865.
In an interview on-site, VTrans engineer Tim Pockette described the new bridge. He said it’s 30 feet wide with two 11-foot-wide lanes and a bare concrete deck with curbing and guardrails. There will be no designated bike lane but the shoulders are generous at 3-feet-wide, and a sidewalk will rest on projecting beam ends outside the travel lane.
Bridge lighting is not part of this job. That decision will be made and funded locally, according to Natalie Boyle with the consulting engineering firm, Greenman-Pederson.
At the south end, Dorr Drive is being moved over 45 feet to align with the south end of the new bridge in a sweeping curve. The roadbed is a sandwich of one foot of sand covered with 18 inches of crushed stone, topped with asphalt. The sand is an “engineered material,” screened to remove fine silt, which holds water. Pockette explained that removing the silt allows rainwater and snowmelt to percolate through the sandy base layer and out into the ditches, thus preventing road collapse and frost heaves.
The new Dorr Drive configuration will move main traffic smoothly from Ripley Road onto Dorr Drive; Clement Drive, entering from the west, will have a stop sign at the intersection. The change will provide better sight distance and a safer intersection, according to Boyle.
As for the impact on Otter Creek, care was taken to minimize disturbance at this crossing, which remains natural except for a retaining wall of marble blocks left over from marble operations here. A temporary bridge of sheet metal plates was installed to provide access to the center pier, and the main river channel flows freely, Boyle said. Provisions for major future flood events include preserving a larger opening for the river by increasing the setbacks for the abutments and using longer bridge spans; embedding pilings 40 feet deep in the ground to support the abutments and the center pier and protect against scouring; and placing large stone fill in front of the abutments and the pier as added protection against moving water.
The goal is for the new bridge to open to traffic in October 2016, with final completion in 2017, at which time CSJ will reconfigure its own entrance onto the new Dorr Drive. Figures obtained from Boyle show the projected cost for the bridge to be $4,607,000 and $12 million for the entire project, with federal funding at 80 percent and the balance split evenly between state and local sources.
Once the project is finished, Otter Creek will return to its scenic tranquillity.