e-mosty June 2018 American Bridges American Bridges | Page 11

SUPERSTRUCTURE
Various sections of a structure were fabricated and
assembled in remote facilities, delivered to
construction site and lifted and joined together. This
modular construction process allows workers to
perform more operations on the ground, rather than
high above the river.
VSL engineers devised a
system of 34
synchronized hydraulic
jacks that could safely
lower the tubs into the
river.
Figure 11: Hydraulic jacks
Precast pile caps for the approach span weighing from
300 to 600 tons were produced at an off-site facility in
Virginia and transported to the site. They were
positioned over a group of piles with a barge-
mounted crane. Holes in the bottom of the caps align
with the piles.
Figure 14: First steel girder assembly makes its way
down the Hudson River
Formwork assembly for the concrete columns and
rebar for piles and pile caps took place at Tomkins
Cove in Rockland County. Precast concrete segments
were formed in Schuylerville, N.Y., as well as at
locations in Pennsylvania and Virginia and shipped to
the construction site. Structural steel for the steel
girders was preassembled at Port of Coeymans, 100
miles north - once fabricated, these two- to three-
span girder sections were sent downriver.
Figure 12: Installing a pile cap tub for the project´s approach span
Concrete was then used to seal the caps to the
exterior of the piles. Following rebar installation, 750
cubic yards of concrete was poured. Once the pile
caps were completed, crew members began building
pier columns.
Figure 15: Steel girders assembled at the Port of Coeymans in
upstate New York and barged directly to the project site
The girders area fabricated with a protective zinc-rich
primer, followed by up to three coats of high-quality
paint, which shield the steel from the elements,
including moisture and salt from the river´s brackish
waters.
Figure 13: Installing rebar in the pier and pile cap
2/2018