Given already-established IAA design
parameters and requirements, BHMM/CTE
assembled a review team consisting of
thermal engineering resources from CTE
as well as construction, engineering and
tunneling expertise from both Bowen
Engineering and Midwest Mole. The team
carefully evaluated the initial design
concepts and proposed recommendations
for IAA consideration. Table 1 summarizes
the differences between the initial utility
connector design and BHMM’s proposal.
After the IAA reviewed BHMM/CTE’s
recommendations, the partners were
given the job of constructing the utility
connector, and as details for the utility
connector were being fully developed,
the IAA decided to add Central Energy
Plant modifications to the project scope.
The result was a two-phased project
totaling $30 million. Phase 1 involved
constructing the 5,890-ft thermal utility
connector, including 8-inch high-temper-
The New Indianapolis Airport
Airport Facts
Largest development initiative in
Indianapolis’s history
Features new 1. 2 million-sq-ft
passenger terminal located between
two existing main runways, plus
new parking, support facilities and
utilities
Terminal to include two concourses,
38 domestic and two international
gates, 96 counter positions, plus a
large pre-security Civic Plaza with
gathering and concessions space
New FAA traffic control tower is the
third largest in the U.S.
In 2007, current airport handled
8. 27 million passengers and an average of 181 daily aircraft departures
Currently served by 10 major and 19
national/regional passenger airlines
and is Federal Express’s second-largest hub
Indianapolis Maintenance
Center Energy Plant
Provides hot and chilled water to
heat and cool the terminal and a
future hotel
9,100 tons of cooling capacity
231,00 lb/hr steam capacity
Connected to terminal via a 5,890-ft
utility corridor tunneled under the
north runway and two taxiways
Source: Indianapolis Airport Authority Web site
( www.newindianapolisairport.com).
Table 1. Utility Connector Designs: Initial Concept vs. BHMM/CTE Proposal.
Initial IAA Concept BHMM/CTE Proposal
Walk-through tunnel (14-ft No-access temporary liner-plate tunnel
outside diameter) (9-ft outside diameter), piping to be
grouted in place after installation
Limited access to vaults
Ductile iron for direct-buried chilled water
piping (chilled-water piping in tunnel to
remain prefabricated carbon steel)
Design-bid (firm price) ‘Target price’ contract (value-engineer
as construction progresses)
Estimated cost: $27 million
Walk-in access to vaults
All piping prefabricated
carbon steel
Estimated cost: $40 million (Based
on construction manager’s estimate
at 60 percent design completion)
Source: BHMM/CTE.
ature hot water piping at 300 psig (with
325 degree F supply and 200 F return
temperatures); chilled-water piping at
150 psig ( 42 F supply and 54 F return
temperatures); electrical power and
telecommunications conduits; and fiber
optic cabling. Phase 2 involved modifying the Central Energy Plant to accommodate delivery of the thermal energy
through the utility connector to the
Midfield Terminal.
Moving Forward
By the time ground was broken for
the terminal in summer 2005, estimates
for the planned utility connector were running much higher than anticipated. This
was primarily because the cost of providing an accessible, walk-through tunnel
structure – a feature of the initial design
concept – was higher than anticipated.
But by late 2005, a utility connector
design/construction team was in place
to move the project forward. As the
overall project lead, BHMM/CTE provided
project management, engineering expertise
on the thermal utility systems, and construction financing. The partners worked
directly with the owner, IAA, through its
technical representative, Aviation Capital
Management. Working for BHMM/CTE were
Bowen Engineering, general contractor;
Midwest Mole, tunneling contractor; Shiel-Sexton, construction manager; and the
Etica Group, tunnel risk management
plan. The project engineer, Parsons
Brinckerhoff, was retained by the IAA.
The team’s initial steps were to
redesign the tunnel portion of the project,
finalize engineering for remaining under-
ground and arbor piping systems, obtain
necessary Federal Aviation Administration
permits and approvals, acquire an appropriate tunnel-boring machine and prepare
a tunnel risk management plan. To meet
the new terminal’s projected schedule
for construction cooling and heating, all
activities progressed simultaneously.
Although using trenchless technology is not a new concept for airfields or
district energy systems, using liner-plate
technology to provide a temporary
2,016-ft-long, 108-inch-diameter opening
beneath a runway and two taxiways
proved to be quite a challenge. To meet
a ‘near-zero’ ground settlement requirement, use of an earth-pressure-balanced
tunnel-boring machine was recommended. The earth-pressure-balanced design
could provide constant pressure at the
drill face and continuous support of the
bored opening back to a point where the
liner plate could be assembled. Near-zero
ground settlement could be achieved by
a continuous grouting operation that
would fill the tail void immediately behind
the liner plates as the tunnel-boring
machine progressed forward.
‘Target Price’ Contract
As design details were being finalized,
a ‘target price’ construction contract
between BHMM and general contractor
Bowen Engineering was also being developed. This approach was offered as a way
to manage and mitigate the owner’s and
contractor’s exposure to risks associated
with the temporary bored opening and
thermal utility installation. Based on information available as of January 2006 and
prior to design completion, both parties
agreed to a target price that then became
the basis for project cost performance.
After it was initially established, this target
