Panel Zone: The area of a column at the beam-to-
Required Strength: Strength of a member, cross
column connection delineated by beam and column
section, or connection required to resist factored loads
or related internal moments and forces in such
Storage Racks: Include industrial pallet racks, movable
Structure: That which is built or constructed and limited
shelf racks, and stacker racks made of cold-formed or hot-
rolled structural members. Does not include other types of
to buildings or no building structures as defined herein.
racks such as drive-in and drive-through racks, cantilever
Structural Observations: The visual observations
racks, portable racks, or racks made of materials other than
performed by the registered design professional in
responsible charge (or another registered design
Story: The vertical distance from the top to top of two
professional) to determine that the seismic-force-resisting
successive tiers of beams or finished floor surfaces; and, for
system is constructed in general conformance with the
the topmost story, from the top of the floor finish to the top
of the ceiling joists or, where there is not a ceiling, to the
Structural Performance Level: A limiting structural
damage state, used in the definition of Performance
Story Above Grade: Any story having its finished floor
surface entirely above grade, except that a basement shall
Structural Use Panel: A wood-based panel product that
be considered as a story above grade where the finished
floor surface of the floor above the basement is:
meets the requirements of NEHRP' 7 and is bonded with a
waterproof adhesive. Included under this designation are
More than 6 feet (1829mm) above the grade plane,
plywood, oriented strand board, and composite panels.
More than 6 feet (1829mm) above the finished
Subdiaphragm: A portion of a diaphragm used to transfer
ground level for more than 40 percent of the total
wall anchorage forces to diaphragm cross ties.
building perimeter, or
Target Displacement: An estimate of the likely building
More than 12 feet (3658mm) above the finished
roof displacement in the design earthquake.
ground level at any point.
Testing Agency: A company or corporation that provides
Story Drift Ratio: The story drift, as determined in
testing and/or inspection services. The person in
Sec. 5.3.7 of NEHRP' 7, divided by the story height.
responsible charge of the special inspector(s) and the
testing services shall be an engineer licensed by the state to
Story Shear: The summation of design lateral forces at
practice as such in the applicable discipline.
levels above the story under consideration.
Tie-Down (Hold-down): A device used to resist uplift of
the chords of shear walls. These devices are intended to
resist load without significant slip between the device and
Design Strength: Nominal strength multiplied by a
the shear wall chord or be shown with cyclic testing to not
strength reduction factor, φ
Time Effect Factor (λ : A factor applied to the adjusted
Effective Strength: Nominal strength multiplied by
a strength increase factor to represent the expected
resistance to account for effects of duration of load.
mean strength at the expected deformation value.
Includes variability in material strength and such
Torsional Force Distribution: The distribution of
phenomena as strain hardening and plastic section
horizontal shear wall through a rigid diaphragm when the
center of mass of the structure at the level under
consideration does not coincide with the center of rigidity
Nominal Strength: Strength of a member or cross
(sometimes referred to as diaphragm rotation).
section calculated in accordance with the
requirements and assumptions of the strength design
Toughness: The ability of a material to absorb energy
methods of NEHRP' 7 (or the referenced standards)
without losing significant strength.
before application of any strength reduction factors.