Equipment Type

Heavy Repairs For Short I-84 Bridge

It barely qualifies as a bridge, but the structure carrying I-84 over the Skungamaug River in Tolland, Conn., has a superstructure weighing nearly 400 tons and is costing a little over $2 million to rehabilitate. Bridge No. 00839, located east of the Route 195 overpass next to the I-84 eastbound on-ramp and westbound off-ramp, has a span of just 25 feet — slightly more than the 20-foot mi...

October 08, 2007

It barely qualifies as a bridge, but the structure carrying I-84 over the Skungamaug River in Tolland, Conn., has a superstructure weighing nearly 400 tons and is costing a little over $2 million to rehabilitate.

Bridge No. 00839, located east of the Route 195 overpass next to the I-84 eastbound on-ramp and westbound off-ramp, has a span of just 25 feet — slightly more than the 20-foot minimum to make it a bridge under federal rules — but its repair by Rotha Contracting of Avon, Conn., is complex nevertheless.

Undertaken with federal participation, utilizing OnSystem funds, the project calls for removing and replacing in-kind the existing precast concrete deck beams that comprise the superstructure because routine inspections by the Connecticut Department of Transportation revealed the existing beams exhibited heavy cracking and delaminated concrete.

Built in 1954 and reconstructed in 1978 as part of the widening of I-84, the short bridge is 181 feet wide and carries four lanes of I84 traffic in both the eastbound and westbound directions separated by a raised earth-style median with jersey barrier. Rotha's crews are replacing the deteriorated deck beams with 43 similarly sized units manufactured by Rotondo Precast's Rehoboth, Mass., plant. Each of the precast, prestressed concrete beams measures 4 feet wide, 18 inches deep and 25 feet long. Beams are cast with voids to make them lighter, but even with that they each weigh about 9 tons.

Construction is being performed in two stages over two construction seasons, with the contractor required to provide two through-travel lanes and a ramp lane in each direction on the interstate during each stage.

Crews constructed a temporary plywood deck beneath existing beams before removing them, to prevent debris from entering the river. Existing beams are removed by Rotha's 70,000-pound Volvo excavator and replaced with new ones from Rotondo. The contractor employs a 90-ton Grove hydraulic crane to offload delivery trucks and position beams side by side across the two concrete abutments, leaving a 1/2-inch space between them that is filled with grout. Beams are later post-tensioned together forming a monolithic concrete superstructure. Workers cover the beams with a waterproof, woven-glass membrane.

With the membrane in place, subcontractor CT Paving LLC of Rocky Hill, Conn., installs Superpave asphalt pavement. Tilcon is supplying the mix from its plants in Manchester and Newington, Conn. Three types of Superpave are applied: a fill mix containing 1-1/2-inch stone, a top course containing 3/8-inch stone, and a temporary pavement mix for traffic lane switches containing 1/2-inch stone. In some places, the Superpave is up to 22 inches deep.

The paving contractor is using an Ingersoll Rand Blaw-Knox PF3200 paving machine to install the material, and two CAT rollers — a 12-ton CB-634C and a 5-ton CB-334D — to compact the material to Superpave specifications.

As part of the work, Rotha is making repairs to existing abutments, building new concrete parapets and bridge approach slabs, and restoring the earth median.

The entire project is expected to take about 20 months.

(Key personnel interviewed for this project include: for the Connecticut DOT, Jeff Benoit, chief inspector; for Rotha Contracting, Jack Thavenius, project engineer; for CT Paving LLC, Christian Hamilton and Kevin Beausoleil, paving foreman.)

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