pit design question (civil)
pit design question (civil)
(OP)
hi~~
U = 1.4(D + F)...............(1)
U = 1.2(D + F + T)+1.6(L + H)+0.5(Lr或S或(2)
U = 1.2D + 1.6(Lr或s或R)+(1.0L或0.8W)...(3)
U = 1.2D + 1.6W + 1.0L + 0.5(Lr或S或R).........(4)
U = 1.2D + 1.2F + 1.0E + 1.6H + 1.0L + 0.2S ............(5 )
U = 0.9D + 1.2F + 1.6W + 1.6H ......................(6)
U = 0.9D + 1.2F + 1.0E + 1.6h.......................(7)
I design a pit now, and i dont need to consider wind load and earthquake at this area
if i consider combination 6 &7 and have not water inside pit
U = 0.9D + 1.2F + 1.6W + 1.6H ......................(6)
U = 0.9D + 1.2F + 1.0E + 1.6H.......................(7)
F=0, w=0, E=0 0.9D+1.6H H including groudwater, this combination make uplift load too large (1.6 multi)
let my analysis model error (compression only spring have tension)
actually uplift check is ok , consider this combination reasonable ?
U = 1.4(D + F)...............(1)
U = 1.2(D + F + T)+1.6(L + H)+0.5(Lr或S或(2)
U = 1.2D + 1.6(Lr或s或R)+(1.0L或0.8W)...(3)
U = 1.2D + 1.6W + 1.0L + 0.5(Lr或S或R).........(4)
U = 1.2D + 1.2F + 1.0E + 1.6H + 1.0L + 0.2S ............(5 )
U = 0.9D + 1.2F + 1.6W + 1.6H ......................(6)
U = 0.9D + 1.2F + 1.0E + 1.6h.......................(7)
I design a pit now, and i dont need to consider wind load and earthquake at this area
if i consider combination 6 &7 and have not water inside pit
U = 0.9D + 1.2F + 1.6W + 1.6H ......................(6)
U = 0.9D + 1.2F + 1.0E + 1.6H.......................(7)
F=0, w=0, E=0 0.9D+1.6H H including groudwater, this combination make uplift load too large (1.6 multi)
let my analysis model error (compression only spring have tension)
actually uplift check is ok , consider this combination reasonable ?






RE: pit design question (civil)
Your question is not clear enough to answer properly.
RE: pit design question (civil)
RE: pit design question (civil)
Uplift is large with buoyant forces - displaced water = 62.4 pcf and weight of concrete = 150 pcf X .6 = 90 pcf.
Net gain of only 27.6 pcf.
RE: pit design question (civil)
thank for your replied
Sorry my roughly describe and i cant upload sketch right now i will do it later.
my pit almost 60 m x 60 m depth 5.5 m (underground)(bottom of baseplate)
wall thickness (0.6 m) baseplate thickness (1 m)
and water level at -3.6m so pit be submerged in groundwater 1.9 m.
My Situation like hawkaz
when i did buoyancy check without any load factor
only concrete weight / uplift force >1.2 ok ( almost 1.2).
But during finite element analysis ,
i consider the case of backfill with groundwater but without internal liquid
U = 0.9D + 1.2F + 1.6W + 1.6H ......................(6)
U = 0.9D + 1.2F + 1.0E + 1.6H.......................(7)
F=0 , w=0, E=0
=>
U=0.9D +1.6H
this combination make uplift force too large.
so i think that i dont consider wind load and earthquake
i still need to consider these two combination or i can ignore it