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Steel joists, considered as a part of
structural steel, are recycled at a rate of 96 percent - significantly
lowering energy use and the nation's demand for virgin raw material.
Choosing steel joists is an environmentally-correct decision, and it
qualifies for LEED credits for 'green' building design.
Steel Joists: The Choice For Green
Building And Sustainable Design Steel is the most recycled material in
North America, according to the Steel Recycling Institute. More than 68
million tons are recycled each year. In fact, all new steel made in
North America contains recycled steel.
For architects and engineers working to
achieve sustainable design, a building created with steel joists and
other steel structural components significantly boosts the amount of
recycled products used in the project - a plus when working to achieve
LEED® (Leadership in Energy and Environmental Design) credits. The LEED
certification program was developed and is administrated by the U.S.
Green Building Council, a national non-profit organization, created to
encourage design and construction that enhances energy and water
efficiency, conserves material and resources and enhances environmental
quality and lessens environmental impact.
In addition to its 'green' nature, design
flexibility is also an advantage to steel joist construction. Based on
the span of building bays, steel joists allow for maximum headroom. They
also offer flexibility to allow pipes and ducts to run through joist
open webs, a procedure not possible with other types of construction.
Design flexibility of long spans is also possible with steel joists.
Spans of more than 100 feet are not uncommon. In
concrete construction, the greater number of support columns needed
often limits the designer's ability to move walls and partitions when
buildings are remodeled. This is an important factor in new construction
as well as remodeling or adaptive reuse.
Another factor enhancing the
sustainability of steel joists is the high strength-to-weight ratio
(typically 25 to 1) allowing steel joists to support greater loads.
Steel can also perform in both tension and compression, unlike concrete
which must be steel-reinforced to resist tensile forces. Steel is also
very ductile, making it more forgiving than concrete in earthquakes.
And, steel can take uplift and gravity loading because steel has
inherent strength in each direction.
Another feature of steel, in general, is
durability. When properly protected against rust and corrosion, steel
joists and other steel structural members can last indefinitely making
them ideal in adaptive reuse projects. Because steel joists have such a
high recycled content they already qualify for more LEED certification
credits, but using existing joists in adaptive reuse of an existing
structure increases LEED credits even more.
The Steel Joist Institute offers a
valuable tool to structural engineers, designers and architects for
determining load-carrying capabilities of steel joists in buildings
requiring renovation or reconstruction. The SJI 75-Year Manual has a
complete listing of live and dead load tables throughout the 75-year
period since 1928. It offers step-by-step investigative procedures and
time saving data for use when analyzing existing structures as well as
building site information and equipment needed.
This manual includes a complete
chronological history of all Institute specification and load tables. A
new section features examples for calculating moment of inertia of older
joists. This guide is considered by the industry as the best and
clearest guide for investigative purposes.
When it comes to creating 'green
buildings' either with new or reused steel joists (in adaptive reuse
projects), choosing steel joists is an environmentally-correct decision,
and it qualifies for LEED credits. |
