Construction on the Francis Scott Key Bridge began in 1972 to address traffic problems and the region has lost a major transit route.
In the early 1960s,the Baltimore Harbor Tunnel (Interstate 895) had reached its traffic capacity,and motorists encountered heavy congestion and delays almost daily during rush hours. Plans were formulated for a second tunnel,but construction bids came in substantially higher than expected,and focus shifted to construction of a bridge.
The benefits of the plan were numerous:additional traffic capacity,lower maintenance costs,and the ability to handle vehicles carrying hazardous materials,which are prohibited in the tunnel.
Construction began in 1972,and the four-lane span opened five years later. The arched steel bridge most recently handled about 11.3 million vehicles a year.
“From the city of Baltimore’s perspective,it was instrumental in providing an alternative to the tunnel for traffic,” said Reuben Hull,a civil engineering historian.
With a main span of 365 metres,it was the second-longest continuous truss bridge in the world when it opened,and it remained the second longest in the United States and third in the world,according to the American Society of Civil Engineers. It had a total length of 2632 meters.
The bridge was a commuting route for about 30,000 vehicles a day when it collapsed.
Its condition was rated as “fair” according to the Federal Highway Administration’s 2023 National Bridge Inventory released last June. Inspectors rated its deck,substructure and superstructure – the component that absorbs the live traffic load – as “satisfactory”.
AP