Building Design and Construction Handbook - Merritt - Ventech!

8.56 SECTION EIGHT
Many preengineered steel building suppliers are also able to modify their standard
designs, within certain limits, while still retaining the efficiencies of predesign
and automated volume fabrication. Examples of such modifications include the
addition of cranes; mezzanines; heating, ventilating, and air-conditioning equipment;
sprinklers; lighting; and ceiling loads with special building dimensions.
Preengineered buildings make extensive use of cold-formed steel structural
members. These lend themselves to mass production, and their designs can be more
accurately fitted to the specific structural requirements. For instance, a roof purlin
can be designed with the depth, moment of inertia, section modulus, and thickness
required to carry the load, as opposed to picking the next higher size of standard
hot-rolled shape, with more weight than required. Also, because this purlin is used
on many buildings, the quantity justifies investment in automated equipment for
forming and punching. This equipment is nevertheless flexible enough to permit a
change of thickness or depth of section to produce similar purlins for other buildings.
The engineers designing a line of preengineered buildings can, because of the
repeated use of the design, justify spending additional design time refining and
optimizing the design. Most preengineered buildings are designed with the aid of
computers. Their programs are specifically tailored to produce systems of such
buildings. A rerun of a design to eliminate a few pounds of steel is justified, since
the design will be used many times during the life of that building model.
8.27 STRUCTURAL DESIGN OF
PREENGINEERED BUILDINGS
The buildings are designed for loading criteria in such a way that they may be
specified to meet the geographical requirements of any location. Combinations of
dead load, snow load, live load, and wind conform with requirements of several
model building codes.
Standards in ‘‘Metal Building Systems,’’ Metal Building Manufacturers Association,
1300 Sumner Ave., Cleveland, OH 44115 discuss methods of load application
and maximum loading, for use where load requirements are not established
by local building codes. Other appropriate design specifications include:
Structural Steel. ‘‘Specification for Structural Steel Buildings,’’ American Institute
of Steel Construction, One East Wacker Dr., Chicago, IL 60601.
Cold-Formed Steel. ‘‘Specification for the Design of Cold-Formed Steel Structural
Members,’’ American Iron and Steel Institute, 1101 17th St., NW, Washington,
DC 20036.
Welding. ‘‘Structural Welding Code,’’ D1.3 and ‘‘Specification for Welding Sheet
Steel in Structures,’’ D1.3, American Welding Society, 550 NW LeJeune Rd., Miami,
FL 33152.
The Systems Building Association promotes marketing of metal buildings and
is located at 28 Lowery Dr., P.O. Box 117, West Milton, OH 45383.