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Project Story
This four-span, 350-foot-long prestressed concrete adjacent box beam bridge that exhibited advanced deterioration of the beams and, therefore, was slated for rehabilitation. The bridge carries traffic over the Chemung River, and the road north of the bridge is within the 100-year flood plain and is overtopped during high water events. Many of the structural deficiencies were in the bridge superstructure, common in bridges of its era. Cracks in the deck facilitated water migration to the interior beam fascias, causing corrosion of prestressing strands. The fascia beams exhibited significant cracking, spalling, and hollow-sounding concrete on the vertical outside faces, and utility conduit supports on the west fascia failed due to exposure to snow and road salts.
Fisher’s solution replaced the entire superstructure along the current alignment with a four-span continuous steel multi-stringer superstructure and concrete deck. The new superstructure and integrated abutments eliminated three lines of bearings at the piers and longitudinal joints between beams, as well as created a low-maintenance, jointless bridge for the next 50 years. The piers and abutments were repaired and modified to accommodate the upgrades.
The steel replacement superstructure was an upgrade for the following reasons:
- It is a lighter, more efficient superstructure
- It was constructed with a shallower cross-section, improving the freeboard over the design flood elevation
- All the surfaces are able to be thoroughly inspected, eliminating the blind details found in adjacent box-beam superstructures
- It was the most constructible superstructure type for this project location
The Chemung River flow favors the south side of the channel, where there is no bank space to place a crane without placing temporary fill in the river. Our solution allowed the contractor flexibility in the approach to both demolition and erection; existing beams can be removed, and new beams erected either from a portion of the superstructure in stages or from a combination of ground-based cranes and barge-mounted cranes.
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