ASCE 7 Flood Loads
ASCE 7 Flood Loads
(OP)
Hi,
We have a concrete retaining (flood wall) that will be resisting flood loads. I have been using ASCE 7 and ASCE 24 in determining applied flood load.
I have a multi-part question
1. In ASCE 7-10 section 5.4.4.2 "Breaking Loads on Vertical Walls". It's unclear if I should use Pmax = Max. combined dynamic and static wave pressures and/or Ft = net breaking wave force. I used them together to find my forces on the wall. Is this over conservative? Should I only use one or the other? If I should only use one, how would you determine which one and why?
Pmax = Cp*Yw*ds + 1.2*Yw*ds [lb/ft^2]
Ft = 1.1*Cp*Yw*ds^2 + 2.4*Yw*ds^2 [lb/ft]
2. After finding my forces, i'm using load factored combinations. ACSE 7-10 uses 2*Fa for flood loads, ACI 318-14 uses 1.4*F. Since this is a concrete structure, I assumed ACI code would supercede ASCE. Would you use ACI or ASCE load combinations?
Many thanks.
We have a concrete retaining (flood wall) that will be resisting flood loads. I have been using ASCE 7 and ASCE 24 in determining applied flood load.
I have a multi-part question
1. In ASCE 7-10 section 5.4.4.2 "Breaking Loads on Vertical Walls". It's unclear if I should use Pmax = Max. combined dynamic and static wave pressures and/or Ft = net breaking wave force. I used them together to find my forces on the wall. Is this over conservative? Should I only use one or the other? If I should only use one, how would you determine which one and why?
Pmax = Cp*Yw*ds + 1.2*Yw*ds [lb/ft^2]
Ft = 1.1*Cp*Yw*ds^2 + 2.4*Yw*ds^2 [lb/ft]
2. After finding my forces, i'm using load factored combinations. ACSE 7-10 uses 2*Fa for flood loads, ACI 318-14 uses 1.4*F. Since this is a concrete structure, I assumed ACI code would supercede ASCE. Would you use ACI or ASCE load combinations?
Many thanks.





RE: ASCE 7 Flood Loads
As to question 2, I would use the ASCE 7 factoring for ASCE loads. The 2 Fa combination is for coastal hurricane and nor'easter floods. But I do not see a discrepancy.
ACI 318-11 says:
"9.2.6 — Flood and ice loads
If a structure is in a flood zone, or is subjected to
forces from atmospheric ice loads, the flood or ice
loads and the appropriate load combinations of ASCE/
SEI 7 shall be used."
ACI 318-14 says:
"5.3.9 If a structure is in a flood zone, the flood loads and
the appropriate load factors and combinations of ASCE/SEI
7 shall be used."