The 1952-1955 cantilever truss bridge is being replaced by a $4-5 (depending on source) billion cable stay bridge.
|By The original uploader was Nrbelex at English Wikipedia - Transferred from to Commons by Matthiasb., CC BY-SA 2.5, Link|
|New York State Thruway Authority|
The buoyant caissons rest on steel piles driven to bedrock. The caissons were constructed on land and barged to the site. Some of the piles are 270' long because the bedrock was 300' below river bottom. The 30" steel piles were cleaned out and filled with concrete. [NYCroads]
|New York State Thruway Authority from NYCroads|
It was designed to carry 100,000 vehicles on a peak day. During 1956 it carried 18,000 vehicles per day. Now it carries 135,000vpd over seven lanes, the middle one of which changes directions twice a day. It takes 45 minutes to change the lane. The projection for 2025 is 175,000vpd. [NYCroads]
None of the heavy rail (commuter), light rail, HOV+bus lane ideas considered during the design phase were incorporated in the final design. But it does have a dedicated bicycle and pedestrian span on the north side with scenic overlooks. [NYCroads, hdrinc]
I can't find where I read it, but since the demolition cost of the old bridge would be $140 million, leaving it as a walkway is being studied. A seven lane highway would certainly be wide enough for bicycles and pedestrians. In fact, they could add bus and HOV lanes on the north side.
|New York State Thruway Authority from hdrinc|
|Tappan Zee Constructors|
|By Jim.henderson - Own work, CC BY 4.0, Link|
In June, 2015, the first prefabricated section of three 12' tall and 400' long girders was lifted into place by the Left Coast Lifter. (video) This is the first of 31 miles of girders to build the first 4-lane, 3.1-mile bridge. A second bridge is being built in parallel so that each direction of travel will have its own 4-lane bridge. The girders are placed on pedestals on top of the pier cap. The pedestals "contain structures called 'seismic isolation bearings,' made of steel and a rubberlike material designed to offer some flexible movement (in case of earthquakes) and also to withstand the day-to-day pounding from trucks. The three-girder assemblages will soon be joined by twin-girder assemblages that will carry prefabricated electrical, plumbing and communications lines and complete the width of the span."
The 328'x100' Left Coast Lifter can lift 1,900 tons, and it came to this site through the Panama Canal. The Tappan Zee prefabricated sections weigh between 900 and 1,100 tons. The previous job for this "world's largest floating crane" was to help build the replacement of the earthquake-damaged eastern span of the San Francisco-Oakland Bay Bridge. The crane has three 806hp diesel powered generators to drive the cable winches. The 6,750 ton crane was built in 2009 near Shanghai.
In July, 2016, a crane boom collapsed across all of the lanes of the old bridge. Fortunately, no one was hurt. It was one of the 28 cranes working on the bridge. It was doing the routine task of installing piling using a vibratory hammer. Investigations did not have much to report three days later. (Most pictures show the crumpled boom laying over the old bridge. This link shows the crumpled boom at the crawler base.) The crane was working on one of the 1000 piles needed by the bridge. A pile is a steel tube up to 6' in diameter and 300' long. But Jeff J. Loughlin, the business manager of International Union of Operating Engineers Local 137, had a theory. The Manitowoc MLC 300 crawler crane with a 256' boom was operating from the deck of the new bridge. Jeff's theory is "the pile had struck a very soft spot of river mud and had begun to sink rapidly, jolting the 60-ton hammer into a rapid drop and putting a particular strain on the boom, which buckled." He explained that with an old crane, the operator could take his foot off the break and allow the hammer to free fall and avoid stressing the boom. But modern cranes have a hydraulic braking system that limits the descent rate to 800 feet per minute. The operator had 30 years of experience manipulating cranes. I assume a drug test can be done within three days so that issue has been ruled out.
|By Ramlogue - Own work, CC BY-SA 4.0, Link|
In December, 2016 it hit the milestone of all eight 419' high towers being completed.
NYC CBS News has a list of its articles concerning the Tappan Zee.
|Satellite image captured Jan, 2017 is probably at least two years old.|
|Tito Arevalo posted|
Manitowoc 4600 ringer Crane
|3: This is probably one of the 60-ton hammers mentioned above that the crane crash described above was using.|
|Screenshot from the video on the referenced page.|
Update: OSHA finds faulty equipment caused the Tappan Zee Manitowoc MLC300 crane collapse. It seems like a $13,000 fine for a $4 billion contract is barely a slap on the pinkie.
|Chris Spence posted|
93 ton edge girder... 4100 tappen zee bridge ny yesterday
|Chris Spence posted|
30 ton floor beam. 4100 tappen zee bridge ny stretched out getting that Sunday $$ local 417
Stephen Collins Never seen a cab relocated like that
Chris Spence Was trying to get a good pic but I'm the signal man didn't have time to.
Ben Stalvey several 4100 have moved relocated cabs.
Shane Strickland I ran this crane on the Biloxi Bay Bridge around 10 years ago! Traylor Brothers right?Chris Spence Yea traylor bros.
Aaron Brown posted two photos with just the comment: "New York." Fortunately, the comments confirmed these were of the Tappan Zee accident.
got a Saturday in on new tappen zee bridge in ny, they added a 100' jib onto the 4600. She's got 400' of stick now
The towers were completed Dec 2016 and the main span was connected to the approaches Feb 2017.
|Kevin Downey posted|
Ben Stalvey wow 400 ft sweet
Mike Irish That runs a # 27 boom for the jib. Same boom as what's in a 4100W ringer. That thing is an animal!!