e-mosty June 2018 American Bridges American Bridges | Page 8

.
I. INTRODUCTION TO THE PROJECT
The 3.1-mile twin-span bridge across the Hudson
River between Rockland and Westchester counties is
one of the largest single design-build contracts for a
transportation project in the United States.
Located less than 20 miles north of New York City, the
cable-stayed span crosses one of the widest parts of
the river and will be the largest bridge in New York
State history.
The Governor Malcolm Wilson Tappan Zee Bridge
opened to traffic in 1955 and, until its retirement on
October 6, 2017, was a vital artery for residents,
commuters, travelers and commercial traffic.
Bridge traffic grew to about 140,000 vehicles per day
in 2016, far more than the Tappan Zee was designed
to support. Heavy traffic, narrow lanes and the lack of
emergency shoulders had the potential to create
unsafe driving conditions. As a result, the bridge had
twice the average accident rate per mile as the rest of
the 570-mile Thruway system.
Hundreds of millions of dollars were spent to maintain
the structure in recent years, and the cost of
maintaining it for the foreseeable future rivalled the
cost of the new bridge, with no improvements to
current traffic conditions.
Plans for a new bridge to replace the Tappan Zee
were first discussed in 1999, and over the following
decade, $88 million taxpayer dollars were spent, 430
meetings were held, and 150 concepts were
considered – yet still, the project did not move
forward.
Under Governor Andrew M. Cuomo’s leadership and
with the support of President Barack Obama and the
U.S. Department of Transportation, the project moved
forward to construction. Since October 2011, new
design-build legislation was enacted, a fast-tracked
federal environmental review and concurrent
procurement processes have been completed, a
project labor agreement with construction unions was
negotiated, and construction activities commenced –
all with an unprecedented level of transparency and
community involvement.
II. DESIGN
The Governor Mario M. Cuomo Bridge has eight
general traffic lanes, breakdown/emergency lanes,
and a state-of-the-art traffic monitoring system. The
new crossing will be mass-transit ready, with space for
Bus Rapid Transit as well as a design that can
accommodate future heavy rail.
The cable-stayed main span is supported by eight 419-
foot high chamfered towers. All towers stand at a 5-
degree angle. The towers support the deck with 192
stay cables, which are made up of 4,900 miles of steel
strands.
The westbound span will feature a 12-foot wide
shared-use path for pedestrians and cyclists. Six
overlooks—each with a unique theme, seating, and
shade structure—will project out over the river.
The bridge’s roadway will be illuminated at night with
dark-sky compliant LED light fixtures to reduce light
pollution. The state-of-the-art system will also
accentuate the bridge’s architectural features,
including the iconic towers, stay cables, and piers, all
while using an estimated 75 percent less energy than
traditional lighting technology.
The bridge is designed so that major maintenance will
not be necessary for at least 100 years.
Figures 2 + 3: Location of the bridge on the map
Source: maps google
2/2018