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Transportation
Clearing Security with 10,000 Tons of Steel
(midwest.construction.com,
September 2006 issue)
By Steve
Kaelble
Care to clear airport security carrying
10,000 tons of steel?
Luckily, the Hunt/Smoot Midfield Builders,
the joint venture that's building the new terminal midway
between two parallel runways at Indianapolis International
Airport, didn't have to. That's because the airport perimeter
fence snakes down in between the two main runways, allowing
the massive project to take place outside of airport security.
"The airport perimeter fence surrounds
the construction site, so we've been able to construct this
facility outside of the secure area," said Rich Potosnak,
president of Aviation Capital Management, program manager
serving the Indianapolis Airport Authority. "We did not have
to have all of the construction workers have FAA badges."
Part of Billion-Dollar Project
The $413 million Midfield Terminal is part of a roughly $1
billion project to modernize and improve the airport.
Two other major elements are already finished: a massive
reconstruction of Interstate 70 just south of the airport-adding
lanes, moving part of the roadway and constructing a new interchange
that will serve the new terminal-and a new air-traffic control
tower.
The >> roadwork was done at the end of 2004, and the
control tower began overseeing aircraft operations in April.
Ground was broken for the new terminal in summer 2005, and
construction is due to be complete in 2008. When it opens,
the existing terminal will be closed. Future use of that complex
is undetermined, but Potosnak said it will not involve commercial
aviation.
"The new terminal is the next step in the airport's
master plan," Potosnak said. The existing terminal sits
to the east of the two parallel runways, built in the early
1980s.
The new, 1.2 million-sq.-ft. terminal will be bigger than
the existing facility. It will include four more aircraft
gates initially, with 20 in a north concourse and 20 in a
south concourse.
Potosnak said another 20 gates can be incorporated into the
terminal design, and a satellite concourse system could one
day bring the total number of gates to about 100 if demand
requires.
Security-Oriented Design
Design work began in 2002, making it the first terminal project
to be designed from the ground up after Sept. 11 changed airport
security forever.
"The facility is designed to Transportation Security
Administration security standards, and we'll have an inline
baggage-screening system," Potosnak added.
But airport officials were well aware that needs and requirements
are likely to continue evolving, so the design has built-in
flexibility, including large, relatively column-free spans
under a massive steel structure.
Dave McLean, vice president of the Thornton-Tomasetti Group,
the structural engineer in Chicago, said the roof is supported
by column trees. Each tree is made up of four pipe columns
at an angle, and they extend to the bottom of the roof trusses,
which are running north-south and east-west.
At its tallest point, the roof is about 70 ft. high, and
the roof curves down and is much lower at the sides. There
will be a circular skylight in the roof that is about 200
ft. in diameter, and a mixture of tubular structure and cables
was designed.
The visible, steel structure will allow large areas free
of columns, intended to better accommodate security revisions
in the future.
Also relatively free of columns are the 100-ft.-wide concourses,
topped with wide truss systems. The main terminal includes
about 8,000 tons of steel, with another 2,000 used for the
concourses.
The design allows plenty of natural light and visibility.
Some steel members are up to 110 ft. long, said Mark Mayer,
senior project manager for Hunt/Smoot.
Unlike many of today's airports, forced by security changes
to keep nonpassengers far from the gates, the new terminal
will permit those who are not flying to view aircraft areas.
Large windows on the east side of the main plaza also will
allow a view of the downtown Indianapolis skyline on clear
days.
Mayer said nearly every truss has camber to it to form the
complex curved roof system.
Concession areas will ring the plaza, with about 60 percent
of the airport's concessions located outside of security and
40 percent beyond the security checkpoint.
Security considerations affected the building design in other
ways as well, according to Potosnak.
"We did a blast analysis on the terminal," he said.
"That was another reason a two-way truss system was developed.
We monitored the effects of wind drafts and wind pressure
on the structure. We also simulated a snow buildup to see
where we would have pockets of snow accumulation."
A two-level roadway includes areas for departing traffic
on the upper level and arriving traffic below. An adjacent
parking garage, for which construction began in May, will
include 7,100 spaces. About 5,900 will be for public use,
and the first floor will be reserved for rental-car operations.
Steel Price Rises Avoided
Despite the large volume of steel included in the new airport
terminal, the bottom line was relatively unaffected by global
demand and fluctuating prices.
"We included in the project specifications a clause
that allowed for the owner to share in the risk of steel cost
escalations," Potosnak said.
"We tried to reduce the fears that there was going to
be a major steel escalation. We pegged the steel tonnage rate
to a market index, and if it exceeded a certain amount the
owner would be responsible."
As it has happened, the price of steel has not escalated
beyond that threshold. In fact, at some points of steel acquisition-which
is about 95 percent complete-there were even some price decreases.
Despite building between two operating runways, there has
been no shortage of space for staging.
"The site is roughly 2 mi. long by about 1 mi. in width-it's
quite large," Potosnak said. "When steel is delivered,
it's been going up pretty quickly."
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