the Local Code and the Uniform Building Code (UBC) to determine
seismic force, Fp.
D. The percent horizontal seismic factor is:
%F = (Fp/Wp) x 100
= Cs x 100
If %F is greater than 48, then manual cannot be used, and an
independent analysis and design is required for all bracing
E. Use SHL "A" if %F is between 31-48, use SHL "B" if %F is between 16-
30, and use SHL "C" if %F is 15 or less.
8.3 CONFORMANCE WITH NUSIG
A. NUSIG has developed guidelines as a service to the design
The guidelines are not intended as a substitute for
The design of seismic bracing remains the responsibility of
the design professional who must review the specific project for its
applicability before using or specifying NUSIG guidelines.
B. NUSIG manuals of designs are pre-calculated from 0.05g through 1.00g
in increments of 0.05g.
Unless otherwise shown by SMACNA or NUSIG, provide detailed
structural calculations for VA's review on design of hangers,
supports, anchor bolts, and connections.
Show sizes, spacing, and
length for securing to structural members, and length and sizes of
welds anchored to steel members.
A. Where SMACNA or NUSIG details are incomplete or not applicable, show
complete seismic restrain requirements and coordinate with the
specifications. Coordinate mechanical work with architectural and
structural work. Special provisions and details may be required.
B. Ductwork and Piping Plans and Sections: Show the locations of
required restraints with reference to SMACNA, NUSIG, or special
restraint details, whichever is applicable.
C. Equipment Restraints: Show special details where required. Pay
particular attention to suspended equipment.
The outside air intake and exhaust air louvers shall be located to avoid
condensers, etc. The bottom of the intake louvers shall be located as
high as possible but not less than tree feet above ground level.
Maximum louver velocity shall not exceed 750 feet per minute through the