ASCE7 1.6H + 2.0F Load Combo
ASCE7 1.6H + 2.0F Load Combo
(OP)
Question about the combo including 1.6H + 2.0F (asce7-10).
Structure has a design water table of 4ft. above base of mat slab from geotech report. This is my 'H' hydrostatic pressure. The area is in a flood zone with a design flood elevation slightly above grade, so about 12ft above base of mat slab - the "F" in my load combo. In using the above combination it seems logical that I should discount the 1.6H and only apply 2.0H since doing otherwise would double count the same fluid pressure (only talking about uplift on mat here). I don't see any good explanation of how these are supposed to be combined/separated in the commentary. Any insight?
Related question. If there are no provisions in the building for withstanding 2.0 x F does it make sense to design for this uplift? In my condition the 2.0F means I'd have water at the 2nd story. However, without flood gates/provisions at this level I will have a basement full of water thus negating the 2.0F of head.
Structure has a design water table of 4ft. above base of mat slab from geotech report. This is my 'H' hydrostatic pressure. The area is in a flood zone with a design flood elevation slightly above grade, so about 12ft above base of mat slab - the "F" in my load combo. In using the above combination it seems logical that I should discount the 1.6H and only apply 2.0H since doing otherwise would double count the same fluid pressure (only talking about uplift on mat here). I don't see any good explanation of how these are supposed to be combined/separated in the commentary. Any insight?
Related question. If there are no provisions in the building for withstanding 2.0 x F does it make sense to design for this uplift? In my condition the 2.0F means I'd have water at the 2nd story. However, without flood gates/provisions at this level I will have a basement full of water thus negating the 2.0F of head.






RE: ASCE7 1.6H + 2.0F Load Combo
- In above example, basic water level at 4ft. but during flood 12ft.
- Is the F loading 12ft of head, so 2.0F is 24ft of head. Or is the F loading 2.0 x (12ft - 4ft) = 16ft. of head? In which case you would do 1.6 x 4ft + 2.0 x 8ft...
- Or is the flood measured from grade and the 2.0 is a factor on the above grade elevation?