The Leonard P. Zakim Bunker Hill Memorial Bridge is a cable-stayed bridge across the Charles River. The main portion of the Zakim Bridge carries four lanes each way (northbound and southbound) of the Interstate 93 and U.S. Route 1 concurrency between the Thomas P. "Tip" O'Neill Jr. Tunnel and the elevated highway to the north. The bridge and connecting tunnel were built as part of the Big Dig, the largest highway construction project in the United States.[1]
Coverage[]
The Leonard P. Zakim Bunker Hill Memorial Bridge is featured in The Bodies Left Behind starting in 75 years after people.
In this segment, time and nature are wearing away the Bunker Hill Bridge. The show then explains the features of bridge by stating that the bridge is span by steel and concrete, held up by 116 cables strung from 2 towers, and required constant maintenance in the time of humans. Helmut Ernst stated that maintenance are always painting the steel in order to prevent corrosion, also including clearing the debris off the bridge, cleaning the drainage structures to prevent plants grow and water flows, and sealing the concrete with a moisture-preventing sealer.
The show continues that the cables are coated in a plastic piping to keep moisture and another source of corrosion. Steven S. Ross stated that bird droppings are known to be corrosive for wide range of building materials, and was not fully recognized by the public 20-30 years ago. The show explains that the waste products of pigeons and starlings contains high levels of ammonia and salt, combine with rainwater it triggers a lethal electro-chemical reaction. It also explains that the bird droppings are known to penetrate the steel of the eight-lane I-35W bridge in Minneapolis that 20 years of bird droppings have contributed to the 2007 fatal collapse.
Its fate is revealed in 100 years after people when weather and stress have cracked the protective plastic coatings on the bridge. The steel corrodes when storm water mixed with acidic pigeon dropping penetrates it, causing the cables to snap. One by one, it snaps till half of it remain can no longer support the weight of the roadway, causing the Leonard P. Zakim Bunker Hill Memorial Bridge to warp and collapse.
Trivia[]
- In the birds/far view, the bridge just wiggle instead of the collapse as seen in the deck view, possibly a visual error, or forgot to create the actual collapse.
Gallery[]
