Question

Waterproofing will prevent groundwater from entering the vault. It is estimated that the vault has a weight of 35 kips, exclusive of the vault floor, which has a thickness equal tot. A sump pump will prevent any water from accumulating inside the vault. A factor of safety of at least 1.5 is required to guard against buoyant uplift of the vault. Write an equation for the buoyant uplift force on the vault; then, compute the floor thickness (t) in feet required for a factor of safety of 1.5 against uplift. Neglect the weight of the sump pump, the weight of the lift station equipment, and any sliding friction between the sides of the vault and the surrounding soil. (3 points) 3 feet Lift Station Vault 9 feet 7.5 feet Figure 1.1 - Lift Station Sketch

Answer 1

3 CUP g' lift station vault 7,5' of rould W = 35 laps weight volume of voudt under water - 7.5 * (9++) Force of bugoyancy on the vault .. Fe = weight of the volume of liquid displaced - density of water x volume Fo 62.42 * 7.5.9 7.5(3+4) weight of the vault en equilibrium condition since, Bugoyant Fesse = Korter of safety (fos) FB = 35*103 lbs 5) 62.42 * 7.5 (9+ 4) = 35x10 visu an.oft १०। lis 3 TS f - Flood thicknees required f = 24.01