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Often referred to as the “City of Brotherly
Love,” Philadelphia has stamped its mark in
history many times over. William Penn, who had
received the title to Pennsylvania in a land
grant from King Charles II of England, first
established a site for Philadelphia in October
1682, and the community was incorporated as a
city in 1701. Since that time, it has hosted many
significant assemblies where historic documents
such as the Declaration of Independence and the
Constitution have been drafted and signed; served
as residence to prominent citizens and statesmen
such as Benjamin Franklin and Betsy Ross; and is
home to the Liberty Bell and first American flag.
So it is only fitting that a city that has
received such accreditation is now host to
another great landmark, the National Constitution
Center, which opened its doors on July 4, 2003 at
the northern end of Independence Mall.
The National Constitution Center was established
by the Constitution Heritage Act of 1988, which
was passed by Congress and signed at the time by
President Ronald Reagan. The Act created the
Center as an organization and first established
building the facility as an important national
goal. On September 14, 1998, the architectural
firm of Pei Cobb Freed & Partners and the exhibit
design firm Ralph Appelbaum Associates -- both of
New York -- were commissioned for the project,
which is the first museum devoted to honoring and
explaining the U.S. Constitution. The design of
the 285,000-square-foot building was conceived by
Henry N. Cobb with partner Ian Bader, along with
exhibit designer Ralph Appelbaum.
And while the building’s design was applauded by
architectural critics, it does veer away from the
traditional red brick found in the majority of
neighboring structures. But the soft tones of
Indiana limestone, which are broken up by 8-inch-
high bands of light gray-colored Chelmsford
granite -- create an unobtrusive design that
meshes well with the surrounding environment.
Introducing the granite bands into the design of
the exterior facade helps to provide a less
formal look -- reducing the scale of the
structure and emphasizing its horizontality.
Complementing the stonework is a two-story glass
entrance, which is called the “front porch” by
Cobb. As Cobb told The New York Times, “It
couldn’t be too official. It’s not a government
building. Nor could it be extremely monumental,
since it is neither a museum nor a shrine. It had
to be more relaxed.”
In total, 10,000 cubic feet -- 33 semi-flat truck
loads or 3,600 pieces -- of Select Buff limestone
from Indiana Limestone Co.’s PM&B quarry in
Bedford, IN, was used for the exterior. The
average panel size measured 4 feet, 8 inches x 3
feet, 4 inches.
“We use a great deal of the material,” said
Project Architect Craig Dumas of Pei Cobb Freed &
Partners. “We’re very familiar with it. One of
the big advantages is that it can be a consistent
stone with a warmth to it, and it’s relatively
inexpensive. We used a higher grade to get the
consistency, and buff for the warmth.
“We complemented that warmth with alternating 8-
inch-high horizontal bands of Chelmsford
granite,” the architect continued, adding that
this material was supplied by Fletcher Granite
Co. Inc. of N. Chelmsford, MA. “We looked at
other granites, but knew that we wanted to use
granite because we wanted to use [the same
material] for the paving and base as well. We
needed a harder stone.”
The architect went on to explain that the
original stone treatment for the National
Constitution Center varied slightly from what
actually was constructed. “We initially went to
Indiana limestone, but we wanted to have ribbed
vertical on the surface of the stone -- to give
texture,” said Dumas. “There was quite a lot of
detailing that went into that. Shortly before the
drawings went out to bid, we had a full-size
mockup on site, with corner detailing and such,
so we could make sure everyone was happy with the
full scale. In the end, the owner didn’t like
the ribbed texture, because it looked too much
like pre-cast concrete. The owner thought it
eliminated the natural veining and coloring of
the natural stone -- it ended up being too
consistent. We actually ran around in circles
looking for other stones with more character, but
that maintained the same likeness in color and
warmth.” But in the end, the decision came back
to use Indiana limestone. “In the end, we and
the owner were satisfied that it had enough
lively character.”
The quarry where the Select Buff limestone was
produced has been in continuous operation for
over 120 years, according to Chief Executive
Officer Rick Johnson of the Indiana Limestone Co.
“The stone is a favorite,” he said. “A lot of
it has history from back in the 1800s -- it’s
kind of a standard. Other monumental buildings
have been done out of here, including the Empire
State Building, the Pentagon and a lot of
courthouses as well as 17 state capitol
buildings. Using Indiana limestone fits this
monumental building. It’s a big important
national building. It really has a contemporary
look, but it’s also traditional.”
The exterior pieces were fabricated at the
company’s facility in Bedford. It required about
three months or 4,000 man-hours to complete,
according to George James, general manager. “We
run anywhere from 6 to 20 different jobs at a
time,” he said. “This project was integrated
into that load.”
James spoke complimentary of the integration of
the limestone with the granite. “It really does
give a flavor and richness in color as well as
depth,” he said. “When you step back, you
really get a feel of the versatility and
durability of the limestone accented with the
granite.”
One particularly striking element of the exterior
stonework is where a few lines of the
Constitution, beginning with “We the People of
the United States,” was etched into one of the
main facades. “We actually carved in the outline
of the preamble of the Constitution and at the
jobsite stainless steel was inserted,” explained
Sales Manager Duffe Elkins. “It’s a distinctive
feature of the building.”
The exterior stonework, including the granite
pavers, was installed by Lepore/Mark Contractors
Joint Venture of Conshohocken, PA. Turner
Construction of Philadelphia was the general
contractor for the job.
Interior stone panels
As is the case with many projects, budget was a
concern for the owner and architects. As a
result, an alternate solution had to replace
initial plans for the interior design of the two-
story lobby. “Originally, we designed the walls
to be solid stone,” said Project Architect Craig
Dumas. “Unfortunately, when the drawings went
out to bid, it was a ‘hot time’ on the market,
so we had to cut costs. The general contractor
offered savings by using lightweight stone
panels.”
The lightweight stone was fabricated from the
same Select Buff limestone and Chelmsford granite
that was employed for the exterior. Indiana
Limestone Co. and Fletcher Granite supplied slabs
to Stone Panels Inc. of Coppell, TX, who in turn
produced the Ultra-Lite Stone wall panels, which
weighed only 3 1⁄2 pounds per square foot.
“Ultra-Lite Panels are an alternative to solid
heavy stone,” said Craig Carroll of Stone Panels
Inc. “Solid rough sawn slabs of limestone were
sandwiched between two 3⁄4-inch-thick pieces of
aircraft quality aluminum honeycomb by adhesion,
using a proprietary high-strength, fiber-
reinforced epoxy. After curing, the slabs were
cut through their center thickness by a diamond
tip saw, resulting in 1⁄4-inch stone thickness.”
This patented manufacturing process offers
substantial impact resistance and flexural
strength, according to Carroll. The fiberglass
skins directly behind the stone provide an
impermeable waterproof barrier, which eliminates
the necessity for a secondary water barrier.
Approximately 20,000 square feet of Ultra-Lite
limestone was installed as interior wall panels.
It included various angled corners, plus both
convex and concave curved panels, which were
installed over steel stud framing by Dale
Construction Co. of Glenside, PA, said Carroll.
Dale Construction also installed approximately
9,000 square feet of Ultra-Lite limestone panels
on the upper exterior walls over the atrium.
“This was somewhat new for us,” said Dumas.
“We had done limited applications like this
before.” To ease some of the design team’s
reservations, the architects visited a number of
installations that had employed Ultra-Lite Stone
panels. “In the end, it was a pretty efficient
system,” said the architect.
Although expense was an issue, the budget did
permit for solid granite to be used for the
fronts of ticket and information desks inside the
museum. Additionally, granite was employed for a
number of benches, which recognized donors, a
grand stair, and slabs of the material were used
as borders for the terrazzo floor. All of the
dimension stone installation was completed by
Lepore/Mark Contractors Joint Venture.
Groundbreaking for the National Constitution
Center was held on September 17, 2000 -- 213
years to the day the U.S. Constitution was
signed. President Bill Clinton presided over the
official ceremonies, which included the
naturalization of 75 new American citizens and
the announcement of a $10 million gift from the
Annenberg Foundation. According to Dumas,
construction lasted about 27 months, although
there was a hiatus of about six months between
bid and the start of construction.
When the museum opened on the Fourth of July of
this year, national, state and local dignitaries
came to celebrate, as well as more than 22,000
visitors from across the country. An approximate
1 million visitors are expected annually.
Upon seeing the results, all those involved have
expressed delight with the project. “We were
quite sure what we wanted to do,” said Dumas.
“It was a bit of an adventure getting the owner
on board.”
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