Region 1 Spring Assembly – Tarrytown, NY
“The New NY Bridge Project”
By: Sarah Dinwoodie
I attended my first Region 1 Assembly
April 21-22 in Tarrytown, NY. It was a great
experience meeting ASCE representatives from
across New England and New York and learning
about Governors and the larger structure of
ASCE. During the Assembly, we heard a
presentation from Thomas McGuinness, P.E. a
Construction Compliance Engineer from the New
York State Thruway Authority (NYSTA) on the
construction of the New NY Bridge Project. (Due
to security we were not able to take pictures during his
presentation and due to construction we did not tour the
bridge.)
structural rehabilitation of the 1950’s structure
and no structural redundancy to protect the
bridge in case of a catastrophic event. In
addition, there were no bike or pedestrian lanes,
so traffic over the bridge was limited to vehicles.
Old vs. New
The Tappan Zee Bridge had one span with seven
11-foot lanes. It was about 87 feet wide. The
New NY Bridge has two independent spans with
a cable staged main span. Both bridges span 3.1
miles with approximately 2.7 miles of approach.
The New NY Bridge will feature all electronic
tolling and a 12-foot shared use path with six
overlooks. The New NY Bridge will have two
spans together containing eight lanes, four
shoulders, two bus lanes, and a shared use path.
The northbound span will be able 96 feet wide
and the southbound span will be about 87 feet
wide.
Photo Credit: https://www.aecom.com/projects/tappan-zee-bridge/
Former Tappan Zee Bridge
The New NY Bridge is replacing the
existing Tappan Zee Bridge, which spans 3.1
miles across one of the widest points of the
Hudson River connecting South Nyack in
Rockland County with Tarrytown in Westchester
County. After four years of construction, the
New NY Bridge has opened the first span to
traffic. The northbound span is now being used
for two-way traffic.
Why a New Bridge?
The Tappan Zee Bridge was designed and
constructed from 1952 to 1955 with a design
capacity of 100,000 vehicles per day. Before this
project began, the bridge was averaging 140,000
vehicles per day. The Tappan Zee Bridge had no
emergency lanes or shoulders and had accident
rates two times the NYSTA’s average rate. There
was a significant cost associated with the
Photo Credit: https://finance-commerce.com/2017/08/first-span-of-4b-new-york-bridge-
opening/
Construction of the two new spans adjacent to the
Tappan Zee Bridge
Complications
One of the major complications with the project
was tying into the land on either side of the
Hudson. To reduce the amount of land taken by
eminent domain, the NYSTA could only construct
one span while the Tappan Zee was still in use.
The
NYSTA
construction
both
spans
simultaneously until they were approximately