Overturning check on a free standing wall???
Overturning check on a free standing wall???
(OP)
I AM HAVING THIS DISCUSSION WITH OTHER ENGINEERS AND I THOUGHT IN ASK HERE TOO. I AM DESIGNING THIS 15ft FREE-STANDING CMU WALL THAT DOESN’T EVEN HAVE A SMALL ROOF ON TOP.
IT TURNED OUT A 12” CMU WALL WITH A CONTINUES FOOTING WIDTH OF 5ft. I CHECKED THE SOIL PRESSURE (for e=M/P), IT WAS OK.
THEN OVERTURNING????, DO I HAVE TO CHECK THAT FOR A FREE-STANDING WALL???
I AM TOLD THAT CHECK IS ONLY FOR RETAINING WALLS (RM / M > 1.5).
I CHECKED IT ANYWAYS AND IT DIDN’T WORK. TO MEET THE 1.5 RATIO, THE CONTINIUS FOOTING NEEDS TO BE AT LEAST 6.5ft IN WIDTH.
IS THERE SUCH A CHECK FOR A FREE-STANDING (that of <1.5)???
Thanks.
IT TURNED OUT A 12” CMU WALL WITH A CONTINUES FOOTING WIDTH OF 5ft. I CHECKED THE SOIL PRESSURE (for e=M/P), IT WAS OK.
THEN OVERTURNING????, DO I HAVE TO CHECK THAT FOR A FREE-STANDING WALL???
I AM TOLD THAT CHECK IS ONLY FOR RETAINING WALLS (RM / M > 1.5).
I CHECKED IT ANYWAYS AND IT DIDN’T WORK. TO MEET THE 1.5 RATIO, THE CONTINIUS FOOTING NEEDS TO BE AT LEAST 6.5ft IN WIDTH.
IS THERE SUCH A CHECK FOR A FREE-STANDING (that of <1.5)???
Thanks.






RE: Overturning check on a free standing wall???
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RE: Overturning check on a free standing wall???
RE: Overturning check on a free standing wall???
You really must check for overall stability because I wouldn't want to lean my bike on it if you didn't
RE: Overturning check on a free standing wall???
Would a deeper footing (add weight) help with yoru overturning?
What type of load (wind) and what magnitude are you using for overturning?
RE: Overturning check on a free standing wall???
Also, is the footing deep enough to be below the frost penetration level? If so, are you counting on the soil overburden when you do your overturning check?
DaveAtkins
RE: Overturning check on a free standing wall???
The ideal engineer is a composite ... He is not a scientist, he is not a mathematician, he is not a sociologist or a writer; but he may use the knowledge and techniques of any or all of these disciplines in solving engineering problems.
-N. W. Dougherty
RE: Overturning check on a free standing wall???
I would also consider designing the wall to cantilever for a 280 plf (ultimate) lateral force applied at the wall top per the intent of IBC 1604.8.2.
RE: Overturning check on a free standing wall???
RE: Overturning check on a free standing wall???
"shall be anchored to ... or other structural elements" could, however, be considered to be the footing in this case, since this is the ONLY connection pertaining to the wall's overturning stability.
If the cmu wall is a simply span (typically) then the 280 plf represents 1/2 the tributary seismic force that would go into a supporting upper diaphragm. Designing the cmu wall, its connection to the footing and the footing for this same force, without any support from a supporting upper diaphragm (i.e. freestanding), is admittedly a debatable calculation.
RE: Overturning check on a free standing wall???
RE: Overturning check on a free standing wall???
Your footing width doesn't look to be out of range for the wall height, considering you have reasonable wind loads. If you are in a high wind area, I would expect the footing to perhaps be even wider. One thing to consider is to put the footing a bit lower in the ground to take advantage of the soil overburden to resist overturning. Soil is cheaper than concrete.
RE: Overturning check on a free standing wall???
Make sure you develop your wind pressures with ASCE 7 under "Other Structures" and take your Cf value from the sign geometry and Solid Sign at Grade criteria.
RE: Overturning check on a free standing wall???