The oId "outside the kern in two directions problem" 1

[deckard452]

We all know the issue - keep your eccentricity on a foundation inside the middle third (e<L/6) in both directions.

That ensures a sound foundation.

But - I often have to go outside (some clients can be real pains when it comes to spending money on concrete)

So what's the max bearing pressure under the foundation?-

I've got a formula which gives a value for K where K x total reaction divided by the product of the e's gives max pressure.

The formula is too tricky to type here but I'll email an Excel speadsheet if anyone wants one. It's basically a long string of the eccentricities raised to various powers, each with a constant in front.

The formula seems to give fair answers but I don't know where it comes from.

I think it's from a paper by a guy called F K Esling. That's all I know

The question is &quot;Where can I get a copy of the derivation and/or Eslings paper&quot;.

Once I can justify the formula I can include it in my spreadsheets and wave bye bye to hand calcs or 3d computer models.

 

[steve1]

A sidebar to your question. Just today I was asked by a client to do the engineering for an equipment foundation that their designer had laid out. It's hard to describe the shape, but lets just say it had two rentrent corners and one side was on a diagonal. It was obvious that the shape was chosen to minimize concrete costs. When I explained that the cost for doing the engineering could be greatly reduced if the foundation were rectangular (and the load made concentric), and that the savings in engineering would more than offset the added material and labor costs, it became a no brainer for the client.

Just my 2 cents worth.

 

[DRC1]

Try

http://www.lindahall.org.

It is a very large collection of engineering papers. The will copy and fax or email you the paper for a reasonable fee. If it is a U.S. paper, they probably have it. If it is foriegn, they might have it.

 

[aggman]

Dr. Bobby Hardin from the University of Kentucky worked out a direct solution for the pressure distribution under eccentrically loaded rectangular footings with moments about two axes. It was printed in CIVIL ENGINEERING FOR PRACTICING AND DESIGN ENGINEERS, vol. 3, pp. 511-516, 1984. I don't know if you can still get it, but I have used it for years in these situations, assuming that you have a rectangular shaped footing.

 

[deckard452]

Hey - Aggman sounds like you may have exactly what I need. I've looked for that book but can't find it (in Australia). Any chance of a fax or scanned/emailed copy of the pages you quoted. I don't think there is a breach of copyright for a small number of pages.

Thanks in advance.