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Penobscot Narrows Bridge and Observatory facts for kids

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Penobscot Narrows Bridge
Penobscot Narrows Bridge and Observatory - August 2014.jpg
The Penobscot Narrows Bridge. Observatory is at top of west tower; access is provided via elevator from west tower base.
Coordinates 44°33′32″N 68°48′11″W / 44.559°N 68.803°W / 44.559; -68.803Coordinates: 44°33′32″N 68°48′11″W / 44.559°N 68.803°W / 44.559; -68.803
Carries 2 lanes of US 1 / SR 3
Crosses Penobscot River
Locale ProspectVerona Island, Maine
Official name Penobscot Narrows Bridge and Observatory
Maintained by Maine Department of Transportation
Characteristics
Design Cable-stayed bridge
Total length 2,120 feet (646 m)
Height 447 feet (136 m)
Longest span 1,161 feet (354 m)
Clearance below 135 feet (41 m)
History
Opened December 30, 2006

The Penobscot Narrows Bridge is a 2,120 feet (646 m) long cable-stayed bridge that carries US 1/SR 3 over the Penobscot River. It connects Verona Island to Prospect, in the U.S. state of Maine. It replaced the Waldo–Hancock Bridge, built in 1931.

Technical information

The Penobscot Narrows Bridge is one of three bridges in the US (the others being Zakim Bridge in Boston, Massachusetts, and Veterans' Glass City Skyway in Toledo, Ohio) constructed recently using a cradle system that carries the strands within the stays from bridge deck to bridge deck, as a continuous element, eliminating anchorages in the pylons. Each epoxy-coated steel strand is carried inside the cradle in a one-inch steel tube. Each strand acts independently, allowing for removal, inspection and replacement of individual strands. The cable-stay system was designed with a system that uses pressurized nitrogen gas to defend against corrosion.

In June 2007, six reference strands within three stays were replaced with carbon fiber strands – a first in the US. Monitoring on the strands will evaluate this material for future use in bridge designs. These engineering innovations helped the bridge appear in the December 2006 edition of Popular Science as one of the 100 best innovations of the year. The total project cost was $85 million.

The bridge was designed as an emergency replacement for the Waldo–Hancock Bridge. From conception to completion, just 42 months elapsed. A unique project delivery method, referred to as "owner facilitated design/build" partnered Maine DOT with FIGG as the designer and Cianbro/Reed & Reed LLC as the contractor. The elevator system in the tower, which is claimed to be the fastest and tallest elevator in Maine, was installed by Stanley Elevator Company, Inc.

Observation tower

The Penobscot Bridge site also is home to the Penobscot Narrows Observatory, the first bridge observation tower in the United States and the tallest public bridge observatory in the world. The tower reaches 420 feet (128 m) into the air and allows visitors to view the bridge, the nearby Fort Knox State Historic Site, the Penobscot River, and Bay.

The Penobscot Narrows Observatory opened to the general public on Saturday, May 19, 2007. It is open at the same times of the year as Fort Knox (May 1 to October 31).

The elevator has had a series of technical problems, including one on July 1, 2014 when 13 people were temporarily stuck in the Observatory due to the elevator doors not opening.

Closures

The bridge was closed for the first time on December 29, 2013 after ice chunks began falling from the support cables onto the bridge deck. The ice was present from a storm on December 22, but did not fall off until the 29th due to cold weather. Hancock County Sheriff's Deputies began receiving reports of damaged cars that morning and upon inspection recommended to MaineDOT that the bridge be closed. At least five vehicles were damaged and two destroyed by the ice. While MaineDOT estimated that 70% of the ice had fallen by that afternoon, it was feared that reopening the bridge would shake more ice onto the bridge deck. MaineDOT also ruled out sending crews onto the bridge cables to remove the ice as too dangerous but by the following day they were considering bringing in heavy equipment to knock ice off the cables. The bridge reopened on December 30, 2013 after being closed just one day but closed again January 5, 2014 for at least another day, "in anticipation that the ice would melt as temperatures moderated for the first time in days."

The bridge was briefly closed on December 7, 2017 when a woman armed with a shotgun was seen walking across the bridge from the Prospect side to the Verona Island side and then sat on the deck. After closing the bridge, Maine State Police officers negotiated with the woman by loudspeaker, and she surrendered after approximately 20 minutes.

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