Concentrated load on retaining wall
Concentrated load on retaining wall
(OP)
I have a column that comes down on a 8’-0” high retaining wall. The column is pretty large and but does not support a large load (only about 10kips). The building is being designed using IBC 2009 ASCE7-05 occupancy Cat III exp C. Using these figures I am getting a horizontal load at the base of the wall due to wind of 7 kips. The wall thickness is currently 12”. When sizing the stem of the wall and figuring the stability/bearing pressure what would others assume for a spread of this load through the wall?
Some people who I have talked to have said to use 4x the thickness of the wall (4’-0” in this instance) others have said to use a 45 degree spread (16’ for bearing pressure in this instance).
Some people who I have talked to have said to use 4x the thickness of the wall (4’-0” in this instance) others have said to use a 45 degree spread (16’ for bearing pressure in this instance).






RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
Mike McCann
MMC Engineering
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
Mr = 2.4 x 4.5 ft-k against right to left (CCW) lateral
Mr= 2.4 x 5.5 ft-k against left to right (CW) lateral
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
As long as you don't overstress the soil, outside the kern is OK.
Mike McCann
MMC Engineering
RE: Concentrated load on retaining wall
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
On the other hand, a 12" conc wall is very strong, and 7 k is not hugely large, so I have no feel for what load would actually be unsafe.
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
And wouldn't the point load improve your overturning? If you neglect it completely for the overturning calc and you get an acceptable FOS I wouldn't be worried about it. Or did you mean that the lateral load at the base of your column (top of your wall) is 7 kips due to wind? I might be slightly confused.
RE: Concentrated load on retaining wall
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
I need to take my wife to a Dr. appt now, so I will BBIAW about 3 hours, good luck.
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
There is a continuous footing under the wall that was initially sized to resist the soil loads. The vertical loads from the column are minimal(10kips). You would think that this load would help with stability and it does to a point (because it is eccentric from the center of the footing), however the column is tall and has a lot of wind load on it so I need to check the wall including the wind loads.
The wall is a cantilever wall as the building is placed into the side of a hill. There is no floor behind the wall to help resist the wind load. I am trying to figure out how far I can spread the horizontal load in the stem of the wall (the initial question). Think of a standard retaining wall with a horizontal load applied perpendicular to the wall at the top of the wall.
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
Even considering the OTM and sliding factors of safety, what I said is true.
Mike McCann
MMC Engineering
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
The definition of a structural engineer: overdesign by a factor of 1.999, instead of the usual 2.
RE: Concentrated load on retaining wall
RE: Concentrated load on retaining wall
As the wall is a retaining wall (soil assumed) and water intrusion would not be desired, I think that any column would have to be integral with the wall, as a concrete pilaster, or contained within the wall, as a steel pipe column, or it will not work.
Mike McCann
MMC Engineering
RE: Concentrated load on retaining wall
A flexible membrane can solve that issue. At any rate, a concrete wall without a membrane is not usually watertight.