StaadEtc foundation design results

[tjhubo]

It is my first time to use StaadEtc to design a column foundation. The results seemed to be too conservative to me, compared with some design tables. Does anyone have the same feeling with me?

Thanks in advance for your idea.

 

[fleisher]

Need to be more specific. What kind of loading do you have? What is conservative - the steel or the size of the footing?

 

[tjhubo]

The situation I have is just axial load, about 50 kips totally. The Staad results indicated rebar on both bottom and top of the footing.

For this load level, common practice just needs rebar at the bottom of the footing. I am wondering if the staad suggestion is conservative.

 

[ishvaaag]

Codes make for such things. In Spain the last concrete code has made for such "novelties". To such extent that one scandalized and scandalizind headmaster of structural design said in a speech to which I attended ...

"That we won't do such things"

because nearly generalizing 90 deg hooks at bottom rebar (a device to prove bond)

rebar appearing atop (before never seen)

and other jewels sohwing to which extent even those charged with teaching these things are fed with those things that may be needed at specific circumnstances but not in general and the ever growing demanding codemakers decide to include as requirements of general design.

Obviously because the general practice before is not known to have had any bad behaviour (or so is the appreciation of who makes such statements).

There are people of every make out there, but as anyone that has practiced just enough, I can see the real gratuity of many of these novelties, whereas other times are well placed.

And just to touch a related item ... safety factors (or whatever you may want to call them) were derived initially when structures were calculated just 2D and even by approximate (even only too much approximate!) methods ... and we (er, the codemakers) have kept them steady and well for our more precise 3D and computerized methods. Maybe (sure!) a bless ... but a required bless? I understand that soon serviceability would start to command even more than today does, yet I keep this question in mind.

 

[lippie]

There is an option in the reinforcement page to "not" choose top reinforcement which I guess is more for shirnk, creep or temperature.