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New York State Thruway Authority

Tappan Zee Bridge Deck Replacement Project

About the Project

Image of workers replacing deteriorated rivets with High Strength Bolts on the Tappan Zee Bridge. Image of workers replacing existing
rivets with high-strength bolts on the Tappan Zee Bridge.

Since September 2007, the Thruway Authority has been replacing significant portions of the deck of the Tappan Zee Bridge.  The work has been part of the Thruway Authority’s ongoing commitment fulfilling its responsibility to maintain and operate the bridge by continuing to make the necessary investments to assure safe and efficient travel for the thousands of motorists that cross the bridge daily.

To keep the public informed, the Thruway Authority uses Variable Message Signs along the highway and Highway Advisory Radio, 530 AM in the Tappan Zee Bridge Corridor, as well as 1610 AM in the Newburgh area.  Project updates, in addition to weekly construction information, are regularly sent to the media. 

Since September 2007, a total of 1,092 new deck panels have been installed, including 288 on the main span of the bridge, 140 on the west deck truss and 664 on the western causeway.

Perini/Tutor-Saliba, JV, of Peekskill, New York, has completed most of the work on Phase I of the redecking project. That contract was awarded in August 2006.

The Thruway Authority in May 2010 awarded a $148.8 million contract for the next phase of the redecking work to Tutor Perini Corp. from Peekskill, New York. This phase calls for the installation of a total of 819 new deck panels, including 216 on the main span of the bridge, 105 on the west deck truss and 498 on the western causeway. Where the first contract replaced the outer four lanes on the bridge, this contract will replace the interior three lanes on the bridge. 

When phase two is completed, approximately 96 percent of the original deck will have been replaced since the bridge opened in 1955.  The installation of the new deck panels began in the Fall of  2011 with the overall project slated for completion in the Winter of 2012.

As the redecking effort progresses, the Authority will continue to implement a number of strategies designed to minimize the impact of the work on travelers:

  • Deck replacement work will be conducted primarily during off-peak, overnight shifts generally from 8 p.m. until 6 a.m.
  • The Authority will limit the Contractor’s day work, permitting single lane closures as needed.
  • Deck replacement materials will be manufactured off-site, reducing noise on-site and shortening the duration of the project overall.

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About the Bridge

The three-mile Tappan Zee Bridge (view map image), located about 13 miles north of New York City, carries the New York State Thruway over the Hudson River between Rockland and Westchester Counties. The structure serves as a lifeline between New York City and Upstate New York. The Bridge carries about 140,000 vehicles every day with volumes as high as 170,000 vehicles daily. When the Bridge opened in 1955, it carried an average of 18,000 vehicles daily in the first year of its opening.

The Bridge is one of the largest in the United States. It carries traffic across the Hudson River via three dedicated northbound and southbound lanes with  a reversible lane, located along the center of the Bridge, providing a total of seven travel lanes. The lane is reversed twice daily using a moveable barrier to accommodate peak period traffic on weekdays.

An Act approved by the Legislature and signed by the Governor on February 28, 1956, officially named the structure the “Tappan Zee Bridge.” In pre-colonial days, this area was the home of the Tappan tribe of Native Americans; “zee” (sea) is the Dutch name for open expanse of water. In 1994, the Bridge was rededicated as the Governor Malcolm Wilson Tappan Zee Bridge in honor of the former New York Governor. When first built, the Bridge and its approaches originally cost $80.8 million.

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Existing Bridge Conditions

Image of Tappan Zee Bridge
View of existing steel superstructure after removal of existing deck in the west deck truss section of the Tappan Zee Bridge.

Construction began on the Tappan Zee Bridge in 1952, which  was opened to traffic in December, 1955. While the Bridge was designed with a capacity of 100,000 vehicles per day, it has carried considerably higher volumes of traffic than originally intended, peaking at 170,000 vehicles per day.

Over the past 50 years, the Authority has completed several significant projects to address structural deck and steel needs on the Tappan Zee Bridge, focusing primarily on the portion of the bridge east of the main span. Recent inspections and increased emergency maintenance repairs indicate that the structural deck and fascia structural steel on the western portion of the bridge have deteriorated. Other areas of deterioration are the concrete walkway, lighting and electrical systems. The recent contracts since 2007 are addressing these issues.

The increased need for maintenance and repair of the Bridge has also resulted in more frequent unscheduled lane closures, resulting in traffic delays for bridge travelers.

Is the bridge safe? Absolutely.

In addition to the Authority’s on-going $2.1 billion highway and bridge Capital Program, a very stringent and thorough Bridge Inspection Program (Program), as mandated by current Federal and State guidelines, is followed.  

In 2010, the Tappan Zee Bridge underwent its biennial inspection as required by NYS Highway Law. The 2010 inspection determined the bridge condition rating to be 3.74, which is up from the 2008 bridge condition rating of 3.71 and continues the upward trend from the 2006 condition rating of 2.96. The improvements in the condition ratings are reflective of the recent investments to the bridge..  As a result of the inspection, no deficiencies that would have resulted in structural flags were found.  Additionally, as of June 2010, there are no active structural flags on the Bridge.  

The Tappan Zee also received a General Recommendation (GR) of 5 during the 2010 Biennial Inspection which has remained the same since 2008 and is,up from its GR of 4 in 2006.  A GR places the greatest emphasis on the items of most importance, the primary members.  A GR of “5” is defined as, “Primary members and substructure are in good condition and do not need major repairs.”  It is important to note, no “red flags” were reported as a result of the 2010 Biennial Inspection. Meaning, there were no deficiencies requiring immediate response supporting the Authority’s position that the structural integrity of the Tappan Zee remains intact and safe for motorists.

In addition to the 2010 Biennial Inspection, a Type 3 Diving Inspection was performed in 2010.  The inspection determined the timber piles continue to be in good condition with no serious structural or scour defiencies noted. These results are similar to the Underwater Diving Inspection done in 2006. The Type 3 Underwater Inspection included the sampling/testing of several of the existing timber piles.  The results of these tests did not detect the  presence of Teredo ship worms. 

In addition to the Underwater Diving Inspections, “test boards” are collected on a monthly basis to check for the presence of marine borer (ship worm) activity in the waters adjacent to the Tappan Zee.  Recent test results have indicated there is no ship worm activity.

In addition to the Federal and State inspection guidelines, the Authority conducts hands-on inspections, has an 80-member crew dedicated to Tappan Zee Bridge maintenance and has installed sensors to monitor the stresses in wind bracings as related to wind speed and temperature.

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About the Deck Replacement Projects

Tappen Zee Bridge Cross Section

From 2007 thru 2009, the Thruway oversaw the replacement of the outside 2 lanes of the Tappan Zee Bridge (Contract #1). This work replaced approximately 40 percent of the original deck, from the main span to the west end of the Bridge. Contract #1 also installed a new traffic barrier in the replaced areas and also installed new roadway lighting on the entire Bridge. Previously from 1996-2000, the Authority replaced half of the length of the center lane of the Causeway and the entire deck on the East Truss section of the Bridge.

The May 2010-awarded project (Contract #2) will replace approximately 28 percent of the total concrete deck area on the Tappan Zee Bridge. When completed, approximately 96 percent of the original deck will have been replaced.

In addition to the deck replacement work, Contract #2 includes installation of additional fencing in a proactive effort to discourage distressed individuals from jumping off the Bridge.

Also under this Contract #2 the existing movable barrier, deployed to shift traffic flow during peak hours, will be replaced.

When substantially complete in the Winter of 2012, the new deck, along with the other associated improvement work, will provide more reliable service, increase safety and add convenience for motorists using this vital east-west corridor. The deck replacement effort is part of the New York State Thruway Authority’s mission to provide safe, reliable service to its customers.

Tappen Zee Bridge Cross Section
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