North Shore Infrastructure
- It's More than New Stadiums
by Geoffrey B. Nara, P.E., L.A. Pittsburgh
Several new jewels are rising on the Pittsburgh skyline, with
their construction adding to the excitement of an already vibrant
city. Two that get a lot of attention as they take shape on
the North Shore, across the river from the city's central business
district, are the new Pirate's baseball field, PNC Park, and
the new Steelers Stadium for football. It's easy to loose sight
of the other critical engineering efforts going on at ground
level, the North Shore Infrastructure Project.
The project encompasses all roadway, utility, and infrastructure
improvements associated with construction of the new sports
stadiums. But it needed to be more than that. The North Shore
infrastructure work is intended to extend Pittsburgh's downtown
area across the Allegheny River to include the North Shore.
Streets, sidewalks, lights, trees and utilities are integrated
into the designs, intended to expand the downtown area across
the river and to provide for future development of the site
between the new stadiums. Project amenities include granite
curbs throughout the project, brick cross walks, decorative
pedestrian and street lighting, and the use of various species
of trees to accentuate the new facilities and provide mixed
fall coloration throughout the project.
From the outset, the project was a coordination challenge.
In addition to the existing surface streets, which were to be
modified for the new sports facilities and planned future development,
elevated approaches to several linked highways cross the site
on overhead structures. Underground are existing electrical
duct banks servicing the city, water, sanitary and storm sewers,
and thermal lines servicing the existing Three Rivers Stadium,
in addition to all the new utilities servicing the new stadiums.
Two 120" sanitary sewers cross the site, one 30' deep brick
sewer (constructed around the turn of the century) and the other
120" sewer which was tunneled approximately 100' deep,
crossing nearly under an existing pedestrian underpass structure.
Adding to the challenge, an ongoing improvement to Pittsburgh's
riverfront parks along the Allegheny River in the project area
needed to be accommodated in the designs.
Initially, all the roadways in and around the site were developed
as a single project. As the plans progressed, it became apparent
that to accommodate existing traffic and construction of the
new stadiums, the roadway system as initially planned would
be inadequate. Furthermore, the existing system did not provide
sufficient space for the park improvements proposed along the
riverfront. The plans were subsequently developed as four separate
construction phases, each to address specific construction sequencing.
- Phase 1 was developed to accommodate the opening of PNC
Park on March 31, 2001. A new connector street, perpendicular
to the river, was added to the infrastructure to provide traffic
relief for closure of existing roadways during future construction
- Phase 2 was also designed to accommodate the opening of
PNC Park. Phase 2 included relocation of the main circulation
roadway around the stadiums, North Shore Drive, further north
away from the Allegheny River through an existing parking
lot to provide room for the riverfront park. It was also critical
to the schedule to relocate the roadway in advance of riverfront
park construction for the opening of PNC Park
- Phase 3 consisted of the roadways around Steelers Stadium
and through the existing Three Rivers Stadium. This section
was realigned to provide room for a future "great lawn"
area adjacent to the Allegheny River near the new Steelers
Stadium, adding to the riverfront park feature. Another key
roadway was also realigned to provide space for a future amphitheater.
This section was designed, from preliminary through final
design in three months, to accommodate demolition of Three
Rivers Stadium in early 2001 and opening of Steelers Stadium
in August of 2001.
- Phase 4 is a pedestrian underpass structure carrying North
Shore Drive over the pedestrian walkway from the riverfront
park to the new Steelers Stadium. The structure was initially
a single span structure that evolved into a three-span steel
continuous multi-w-beam structure. The beams are sized and
the steel details along the parapets were designed to match
the steel shapes used throughout the Steelers Stadium. In
addition, the skew angles of the abutments as well as the
piers vary based on splay lines from the center of the stadium.
The structure is clad with stone veneer matching the stadium.
Phase 4 was designed to accommodate the construction schedule
of the bridge, to be opened by the first Steeler game in the
new stadium in August 2001.
Three separate sewer projects were bid: one sanitary project
and two storm projects. The sanitary sewer project involved
placement of deep sewers, a portion of which were jacked and
bored from a downshaft along the Allegheny River. A 42"
storm sewer was jacked and bored nearly 700'. Another advanced
storm system connected an existing outfall to the Allegheny
River, with the new roadway system designed to accommodate construction
of a stormwater detention basin required for demolition of Three
As with any project of this magnitude that also has an extremely
aggressive completion schedule, total commitment is required
by all parties. The City of Pittsburgh Department of Engineering
and PennDOT District 11-0 especially deserve tremendous recognition
for cooperating and providing timely reviews and approvals,
enabling the project to move ahead on schedule.
Although the two stadiums get nearly all the attention, significant
effort is being spent to ensure that construction proceeds smoothly,
that sports fans will have good access to the facilities, that
utility service meets all the user's needs, that the new riverfront
park improvements will be able to be enjoyed year-round, and
that all these pieces "fit" together. The North Shore
Infrastructure Project does all this successfully. People will
notice this extension of downtown Pittsburgh.
With thanks to Michael Baker Jr., Inc. for their support
and information in the development of this article.
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