Controlled Demolition Inc used 90 kg (200 lbs) of explosives to demolish a recently replaced bridge over the Allegheny River in Allegheny County, Pennsylvania, on behalf of the Pennsylvania Department of Transport (DoT). The demolition took almost three years of planning.
The Harmar Township Bridge, which had carried Pennsylvania Turnpike traffic over the Allegheny River since 1951, was demolished by CDI using 200 lbs of explosives that deposited almost 2000 tonnes of steel in the river below.
Two sections of the bridge that go over land will be demolished at the end of this month (July) and the demolished bridge will be replaced with twin spans that will each carry three lanes of traffic.
The US$200 million project is part of the Turnpike widening and rehabilitation project between the Butler Valley and Monroeville exits.