30 November 1998
design spectral acceleration Sa will equal SDS. Values for T0 and TS are shown in Table D-1. After
the building frame is designed, the building natural period will be calculated to ensure that it falls
between T0 and TS, and corrections will be made if needed.
D3. SEISMIC DESIGN CATEGORY. The seismic design category for the barracks building is
determined from Tables C-3a or C-3b, based on the seismic use groups and values of SDS and SD1. If
the tables give different categories, the larger letter is chosen. For the barracks building, the seismic
design category is D (see Table D-1).
D4. STRUCTURAL DESIGN CRITERIA. The lateral-load-resisting system of the barracks building
will be designed with cold-formed steel shear panels with diagonal straps acting as the sole lateral-
load-resisting element. Values of the response modification factor, R and deflection amplification
factor, Cd are taken from Table 3-1 and shown again in Table D-1.
The diaphragms of the barracks buildings are reinforced concrete and are considered rigid. The
reliability factor, ρx, is calculated using Equation C-7, which for the barracks building for every floor
ρx = 2 -
= - 1.8
rmax x A x
The value of ρx shall not be taken as less than 1.0. Therefore no correction is needed for lateral-load-
D5. BARRACKS BUILDING LOAD CALCULATIONS. The effects of gravity load (dead, live, and
snow) and seismic forces shall be combined as defined by Equations C-12 and C-13. As explained in
Appendix C, Paragraph C5, the total lateral force that must be resisted by the shear panel diagonal
straps is simply defined by ρQE in these equations. In the case of the barracks building this becomes
QE, and the diagonal straps are first sized based on this force.
The barracks building will be designed to act independently in the two orthogonal directions. Figures
D-2 and D-3 show schematic drawings of the barracks building. Figure D-2 shows the plan view and
long-direction elevation. Figure D-3 shows the short-direction elevation of the building. Table D-2
summarizes the weight calculations for the entire building using spreadsheet calculations. These
weights include roof and floor dead load (20 and 40 psf, respectively); exterior wall weight (10 psf);
interior wall weight (10 psf); brick veneer weight (40 psf); and room and corridor live load (40 and 80
psf, respectively). The brick veneer is self-supporting for gravity loads, and vertical and in-plane
lateral seismic forces. The building lateral-load-resisting system (shear panels) does resist out-of-
plane lateral seismic forces from the brick veneer weight. Therefore, the out-of-plane long-direction
brick veneer lateral seismic forces are resisted by the short-direction shear panels.
The short-direction shear panels will be placed at every bay (20 feet, 6-5/8 inches spacing) of the
building as shown in Figure D-2, for a total of nine short-direction frames. A trial shear panel
configuration will be assumed in which two shear panels are placed at every frame, as shown in
Figure D-3. Figure D-3 shows that two shear panels will be placed against the perpendicular outside
walls of the building. Shear panels will be located in the same bay at each floor level, with decreasing
capacity at the higher floor levels.
Barracks Prototype Drawings, Sheet C-1.