DNS - REVIEWED RESUB 1 BLD2021-1646+Vault_Buoyancy_Calcs+5.5.2022_2.18.56_PM+2850506B - VAUL T BUOYANCY CHECK
RESUB
BLD2021-1646 May 05 2022
CITY OF EDMONDS
DEVELOPMENT SERVICES
DEPARTMENT
Page 879 of 1082
Calculations for Buoyancy Check for Vault:
Note: Geotechnical Report did not note encountering a water table in any borings. As a
result, a very conservative assumption that the watertable occurs at the bottom of the
vault lid.
Bottom of Vault:
Top of Vault Lid:
Watertable Elevation (Assumed):
Thickness of Mat Slab (Avg):
Water Depth:
Water Specific Weight: t<\
Elev,ault:=87.5 ft RESUB
May 05 2022
OF
Elevlid :=100 ft DE EI OTY PM NDT SOERV CES
DEPARTMENT
Elevwater := 99 ft
tmat:=0.5•(2 ft+1.5 ft) =1.75 ft
dwater :_ (Elevwater — Elevvault) + tmat =13.25 ft
%water:= 62.4 lbf
ft3
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Vault Square Footage:
(incl. Walls)
Mat Slab Square Footage
(1.5ft beyond basement wall):
Wall Perimeter Linear Footage:
Wall Thickness:
Wall Height:
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SFvault := 209.5 ft - 24.2 ft 5069.9 f t 2
SFinat:=211.5 ft•35 ft=7402.5 ft2
Lext.wall :_ (209.5 ft + 24.2 ft) • 2 = 467.4 ft
twall :=12 in Ox _
hwall := Elevwater — Elevvault = 11.5 ft
Page 880 of 1082
Soil above perimeter Extension:
s
Soil Buoyant Unit Weight 'Ybuoyant.soil:=78 f
(assumed): t RESU B
Soil Buoyant Weight Total:
May 05 2022
W (SF SFvault) • h — 2092.3 kipCITY E
buoyant.soil '— %buoyant.soil � mat vault wall — DEVELOPMENT
SERVICES
DEPARTMENT
Net Uplift without Column Reactions:
Dead Load (Mat Slab):
Dead Load (Wall):'
Dead Load (Wall + Mat Slab):
irk
Dead Load Lid: �S
v.
Total Dead Load:
Water Uplift:
Volume of Vault (below
water table):
Volume of Foundation:
Total Volume Displaced:
Net Uplift:
DL,,,at := tmat • SFinat • 145 pef =1878 kip
DLwall :— twall • Lext.wall • hwall • 145 pcf = 779 kip
DLresist.nocol :=DLmat +DLwall = 2658 kip
DLlid :=150 psf • (209.5 f t • 24.2 f t) = 760 kip
k/ 'DLtotal := DLresist.nocol + DI'lid = 3418 kip
Vvault := (SFvault) ' (Elevwater—Elevvault)
Vvault = 58304 f t3
V fdn'= SFinaf
t' tmat =12954 t3
Vdisplaced:= Vvault + Vfd,, = 71258 ft3
Wuplift:=Vdisplaced'i'water=4447 kip
Upliftnet:=Wuplift—DLtotal—Wbuoyant.soil=-1064.1 kip V� J
Safety Factor:
SF:— DLtotal + Wbuoyant.soil = 1.239
Wuplift
Note: This assumes a water level
much higher than supported by the
geotech report. In addition, this
ignores the dead load from the
podium columns. By engineering
judgement, the safety factor for
buoyancy will be much higher than
1.5 once column loads are
considered.
9x _
:�
Page 881 of 1082