BALTIMORE — Baltimore's Francis Scott Key bridge collapsed Tuesday morning into the Patapsco River when a cargo ship slammed into one of its supports, sending twisted metal and several people into the water below.
Rescue crews continue to search for survivors from the collapse and are beginning their investigation into the cause of the crash, while residents wonder how such a catastrophic incident could occur.
How old is the Francis Scott Key Bridge?
The bridge, oftentimes referred to as the Key Bridge, was originally known as the Outer Harbor Crossing while it was being built in the 1970s.
The Key Bridge officially opened in 1977 as a major link along Interstate 695, which links Washington D.C. to the Baltimore area.
The bridge's construction in the 70s means it was erected before a series of major collapses, including the partial collapse of the Sunshine Skyway Bridge in 1980, forced engineers to rethink how they designed bridges to survive collisions with larger ships that were being phased in throughout the later half of the 20th century.
How long is the Francis Scott Key Bridge?
The Key Bridge has a total length of 1.6 miles, with the longest section spanning 1,200 feet.
At 1,200 feet long, that section of the bridge was the third longest span of continuous truss in the world when it was built. Until its collapse, the Key Bridge was the second-longest bridge in the Baltimore area, smaller only than the Chesapeake Bay Bridge.
How deep is the Patapsco River?
The bay below the bridge is about 50 feet deep. That depth will be an important factor in recovery efforts, as well as efforts to clear the water so that ships can resume traveling out of the bay to the Atlantic Ocean.
The "bridge span clearance," which is a measure for the distance between the bottom of the bridge to the water below, is about 185 feet. The size of many large container ships requires specially trained pilots to steer them out of the Chesapeake Bay and into open water.
Officials confirmed Tuesday morning that the river pilots were in control of the ship when it collided with the bridge.
How many people use the Francis Scott Key Bridge?
More than 12.4 million cars — or roughly 34,000 vehicles every day — used the Key Bridge in 2023, according to a Maryland state government report issued in November.
The bridge is a main thoroughfare for both commuters and commercial vehicles. It was also the only major traffic artery through Baltimore that allowed hazardous materials across. HAZMAT materials are not allowed through the Baltimore Harbor and Fort McHenry tunnels, which are the other passages through the metro area.