FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

Volume II DETERMINING SITE-SPECIFIC LOADS 8
EXAMPLE 8.10. LOAD COMBINATION EXAMPLE PROBLEM (continued)
To adjust w roof for a wall height of 10 ft due to the fact Table 8.7 assumes a wall height of 8 ft:
Finally, adjust this value to account for the reference case in Table 8-7 assuming the lateral floor
diaphragm load is from wind pressures on the lower half of the wall above and the upper half of the
wall below the floor diaphragm. Because the structure is open below the floor diaphragm level, adjust
w floor to account for the presence of only half of the wall area used in the reference case for Table 8-7
(e.g., structure is open below first floor diaphragm):
• For building length = 60 ft, total horizontal shear at the top of the foundation is:
W foundation = (410 plf + 212 plf)(60 ft) = 37,320 lb
Solution for #2: The horizontal load required for foundation design, can be determined using the
following calculations of the load combination equations given in Section 8.10:
• Zone V and Coastal A Zone
5. D + 0.6W + 1.5F a
6a. D + 0.75L + 0.75(0.6W) + 0.75(L r or S or R) + 1.5F a
6b. D + 0.75L + 0.75S + 1.5F a
7. 0.6D + 0.6W + 1.5Fa Load combination No. 5 produces the maximum shear at the foundation for the loads
considered. This load combination includes a wind load factor adjustment of 0.6. Because the
value of Wfoundation from Solution #1 has already been adjusted by 0.6 for ASD, it will not be
further adjusted in the calculations that follow.
For flood load, the value of F a is determined in accordance with Table 8-5. The hydrodynamic
load is greater than breaking wave load, therefore, F a for an individual pile and the foundation as
a whole (i.e., global) is calculated as:
F a(individual) = F i + F dyn = 2,440 lb + 909 lb = 3,349 lb
F a(global) = (1 pile)F i + (35 piles)F dyn = 34,255 lb
5. Total shear:
• Portion of Zone A landward of the LiMWA
5. D + 0.6W + 0.75F a
6a. D + 0.75L + 0.75(0.6W) + 0.75(L r or S or R) + 0.75F a
COASTAL CONSTRUCTION MANUAL
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