Building
& Construction
Uses for aluminum
profiles in the building and construction industry cover a wide range
of products, including windows, doors, railings, bridges, light poles,
high-rise curtainwall, framing members, and other various structures.
BRIDGES
Corbin Bridge, located in Pennsylvania, was refurbished with an extruded
aluminum deck. It has a 320-foot span, and the deck is 12 feet, 6 inches
wide (single lane of traffic).Because the dead weight of the aluminum
is so much less than that of the original construction of steel and timber,
it can now carry live loads of 22 tons, compared to the 7-ton limit prior
to replacing the deck. What this means in practical terms is that a fire
truck can now cross the bridge, which it could not have done previously.
CURTAINWALL
The ability to be formed and to accept a high-grade paint
finish makes extruded aluminum particularly appealing for use in
construction. With superior heat properties and structural integrity,
extruded aluminum
is an ideal choice for constructing unitized curtainwall panels.
Using thermally improved extruded aluminum profiles adds to the
energy efficiency of the building, delivering reduced heat loss/gains
and interior condensation resistance, in addition to assisting
with overall energy conservation. Aluminum's weight-to-strength
ratio saves on overall bulk compared to alternative materials and
allows for greater design flexibility. Case-in-point, thin-walled
aluminum extruded sections can withstand forces of lateral buckling
and high winds, a significant concern with high-rise buildings. Photo: © James Steinkamp, Steinkamp/Ballogg Photograph. Used
with permission from Goettsch Partners, Inc.
WINDOWS
Modern aluminum windows are attractive, energy-efficient, and reliable. Thermally-broken
aluminum window-frame-and-sash construction is appropriate for use in all
climates. Such windows also possess a number of other advantages that make
them the best choice both for new construction and replacement.
Performance
with Minimal Maintenance
Aluminum is a stable material, with consistent and predictable properties.
It doesn't absorb moisture, so it won't swell, shrink, warp, twist, split,
crack or check. It can't rust. Its strength and rigidity are unaffected by
weather and time. Expansion and contraction, both of the building and the window-frame
materials, are two of the factors that determine long-term window reliability
and ease of operation. Over time, aluminum windows are resistant to changes
in temperature and humidity, which can cause some window-frame materials to
bend and twist leading to seal failure, air and water leakage, and difficulty
in opening and closing or swinging and sliding window elements. Aluminum is
a stiff material--23.2 times stiffer than vinyl, and 7.2 times stiffer than
soft wood--so aluminum windows are more resistant to distortion caused by building
movement. Moreover, aluminum windows are available with long-lasting baked enamel
or anodized finishes, adding to their beauty as building components and
ensuring freedom from frequent repainting. Aluminum windows' unique combination
of enduring properties means long-term performance with minimum maintenance.
Today's aluminum windows use long-lasting weather seals that can be easily
replaced after years of service. To maintain attractive appearance, all
you have to do is wipe with a damp cloth to remove surface dirt. Total Thermal Performance
Windows lose heat in several ways: largely by conduction and radiation
through glazing; by conduction through frames; and by air leakage. Today's
effective sealing materials minimize air leakage around glazing and through
the variety of joints. In aluminum windows, thermally-broken framing
members minimize conduction heat loss through frames. These are usually
composed of three pieces: an outer extruded frame; a central core of
insulating material; and an inner extruded frame. The central core acts
as a barrier to heat flow from a warm interior to a cold exterior in
winter, and vice-versa in summer. This modern
construction creates highly thermally efficient frames and enables
window manufacturers to take advantage of other important aluminum
properties-durability, strength, stability and corrosion resistance--for
the benefit of consumers. Manufacturers today use a variety of glazing
methods and frame designs to minimize window condensation, which can
be damaging if it occurs on window frames. By using "thermal breaks" they
make aluminum windows with condensation resistance similar to that of
wood and vinyl windows. It's important to note that heat loss through glazing is independent
of the material of which sashes and main frames are made. It's the same
for windows with frames of aluminum, wood, or vinyl. The total original
(i.e., at installation) thermal efficiency of a window is a measure of
its ability to resist heat loss through glazing, frames, and by air leakage
through joints. Today's aluminum windows offer similar original thermal
efficiency to those of wood and vinyl--plus the additional advantage
of long-term durability, strength, stability, and freedom from structural
deterioration. |