CEMP-E
TI 809-02
1 September 1999
CHAPTER 2
BASIC STRUCTURAL SYSTEMS FOR BUILDINGS
2-1. SELECTION OF STRUCTURAL SYSTEM. The goals in the selection of a load resisting
system are simplicity in the structural framing layout and symmetry in the structural system
reaction to design loadings. The selections must consider the need for economy, function, and
reliability. Structural systems selected must have deformation characteristics that are
compatible with the architectural and other nonstructural building elements and features.
Regular structure configuration, continuous and redundant load paths, and system ductility are
attributes encouraged. These attributes are required of buildings constructed in high seismic
areas.
2-2. COMMONLY USED STRUCTURAL SYSTEMS (Adapted from FEMA 178). The following
is a list of building systems commonly found in existing building construction. These systems
are provided for informational purposes with the understanding that not all the systems listed in
this paragraph are recommended for use in new building construction. Figures illustrating the
types of construction described herein can be found in FEMA 154, "Rapid Visual Screening of
Buildings for Potential Seismic Hazards: A Handbook".
a. Building Type 1 - Wood, Light Frame. Light frame wood buildings are typically single,
or multiple family dwellings of one or two stories. The essential structural character of this type
is repetitive framing by wood joists on wood studs. Loads are light and spans are small. Some
of these buildings are engineered: however, most are not, but are constructed in accordance
with the International One and Two Family Dwelling Code. Shear walls are exterior walls
sheathed with plank siding, stucco, plywood, gypsum board, particleboard, or fiberboard.
Interior partitions are typically sheathed with gypsum board.
b. Building Type 2 - Wood, Commercial and Industrial. Commercial and industrial wood
buildings usually have floor areas in excess of 5000 square feet with few, if any, interior walls.
The essential structural character is framing by beams on columns. The beams may be glulam
beams, steel beams, or trusses. Lateral forces are resisted by wood, or metal diaphragms,
and exterior walls sheathed with plywood, or particle board. The walls may have rod, or metal
strap bracing. Large openings for stores or garages often require post-and-beam framing.
Lateral force resistance on walls with large openings can be achieved with steel frames or
diagonal bracing. Type 2 buildings have been used with some frequency in military
construction, in particular with respect to child development centers.
c. Building Type 3 - Steel Moment Frame. These buildings have frames of steel columns
and beams. The beam-column connections are usually fully developed as a moment
connection to resist lateral forces. Lateral loads are transferred by diaphragms to the moment
resisting frames. The diaphragms can be steel decking, reinforced concrete, or a composite of
steel decking with a concrete topping slab. The frames develop their stiffness by full or partial
moment connections. The frames can be located almost anywhere in the building. Usually the
columns have their strong directions orientated so that some columns act primarily in one
orthogonal direction while others act in the other orthogonal direction, and the frames consist
of lines of strong columns and their intervening beams. Steel moment frame buildings are
2- 1
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