FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

Volume II DETERMINING SITE-SPECIFIC LOADS 8
EXAMPLE 8.8. LATERAL CONNECTION FRAMING LOADS FROM WIND (concluded)
• C&C coefficients are used
• When determining C&C pressure coefficients, the effective wind area equals the tributary area
of the framing members
• For long and narrow tributary areas, the area width may be increased to one-third the framing
member span to account for actual load distributions
• The larger area results in lower average wind pressures
• The increase in width for long and narrow tributary areas applies only to calculation of wind
pressure coefficients
• Determine the tributary area and pressure coefficient GC pf for the wall sheathing: Stud
effective wind area equals 13.33 ft 2 . The minimum required area for analysis is h 2 /3=33.3 ft 2 ,
where h is 10 ft
• In accordance with ASCE 7-10, the pressure coefficient, GC pf , for wall sheathing can be
determined based on a minimum effective wind area of 33.3 ft 2 as follows:
Zone 5:
The design wind pressure is determined as follows from Equation 8.14:
Zone 5:
The required capacity of connectors assuming load is based on half the wall height:
Zone 5:
Note: This solution matches the information in Table 8-9.
8.8 Tornado Loads
Tornadoes have wind speeds that vary based on the magnitude
of the event; more severe tornadoes have wind speeds that are
significantly greater than the minimum design wind speeds
required by the building code. Designing an entire building
to resist tornado-force winds of EF3 or greater based on the
Enhanced Fujita tornado damage scale (in EF2 tornadoes,
large trees are snapped or uprooted) may be beyond the realm
COASTAL CONSTRUCTION MANUAL
WARNING
Safe rooms should be located
outside known flood-prone areas,
including the 500-year floodplain,
and away from any potential large
debris sources. See Figure 5-2
of FEMA 320 for more direction
regarding recommended siting
for a safe room.
8-67