strap foundation design

[Groszni]

hello engtips, im designing a corner foundation, im confused how to calculated the strap footing when you got 2 eccentricity? can i just doing 2 calculations the first with x ecccentricity strapped with the right column and the second with y eccentricity strapped with the bottom column?

http://files.engineering.com/getfil...c7b-3b6d529b055c&file=WANNA_ASK_STRUCTURE.JPG

 

[KootK]

No actually. None of the strap beam footings in your sketch are set up such that they would produce uniform-ish soil bearing pressures. Basically, at least one of your beams has to cross the centroid of the footing. In a double property line scenario, some of your options include:

1) Run your strap beam in diagonally or;

2) Span a triangular footing between beams and reinforce it with top steel rather than bottom.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Groszni]

@kootk im sorry but can you describe with some pictures so i can understand more?

 

[KootK]

Perhaps. What aspect would you like described pictorally?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Groszni]

@kootk about the footing wont produce uniform soil bearing what i know is when the cg of the footing and cg of column isnot on the same line, the eccentricities happen and the soil bearing become uniform and might be cause tension on the side of the footing , and your 1st and 2nd advices please

 

[KootK]

I see your proposal as shown in the sketch below, with there still being eccentricity and, thus, non-uniform bearing pressure under the footing. Like most everything else, it'a a simplified idealization.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.