Opportunity
Below Interstate 90 in Blandford, Massachusetts, a corrugated steel culvert 7 feet (2.1 meters) in diameter and 330 feet (100 meters) long crossed a tributary of Peebles Brook beneath approximately 25 feet (7.6 meters) of fill.
When the culvert collapsed, areas of the highway embankment also caved in. Because I-90 is heavily used, it was important to replace the culvert without any traffic closures.
Solution
Mott MacDonald was retained to evaluate tunneling alternatives and construction techniques. Our recommendation to jack sections of precast concrete pipe nine feet (2.7 meters) in diameter beneath the roadway was accepted.
We designed jacking and receiving pits at the ends of the proposed culvert, and a temporary access road. We also prepared bridge sketch plans, final contract documents, materials estimates, and traffic management and work safety plans.
Outcome
The new concrete culvert was installed parallel to the existing culvert, without closing I-90 to traffic. The new culvert has reinforced concrete headwalls at each end. The stream was diverted into the new culvert, and the old culvert filled with controlled-density fill and capped with concrete walls.