Foundation Design and Resisting Uplift 1

[KCEngineer]

I am designing a foundation for a metal building. I have a frame load but I am considering using the collateral gravity load to resist uplift as well. I am not sure I should??

 

[JAE]

Meet the service load combination of 0.6D + W

 

[csd72]

Only include permanent loads to resist uplift.

 

[msquared48]

Been designing these foundations for 30 years and not one has ever failed by using the dead load of the structure.

No worries here...

Mike McCann
McCann Engineering

 

[abusementpark]

Isnt the collateral load classified as an additional live load? I have seen it used on metal buildings a lot lately with not much explanation.

 

[SalsaDude]

What happens when the collateral load isnt installed, doesn't that present a problem?

 

[rday]

The last one I did, collateral load was used for permanently attached mechcanical/electrical equipment.

Permanently attached seems to fall under dead load.

Didn't the building supplier provide reactions?

 

[PEinVA]

If I have a combined footing, (actually a small mat, like 24x36) and in my model it has a handful of springs which show some small uplift, less than weight of foundation, not included, but 95% of the foundation is in compression with the soil, is this acceptable?

It's hard for me to wrap my head around so many load combinations and having to design a combined footing for 10 columns or so, and making sure it survives even distribution every time, since the loads on the columns change, so does the center of load, and then I have to modify the size of the foundation, when does this end?

Thanks.

RC
All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke