Concrete Spring Constant for Base Plate Modeling
john yang
I am modeling base plate on the 6000 psi concrete column and I want to put concrete compression only spring to represent concrete. The problem is what is the compressive spring constant of concrete. Could you help me to get it?
Thank you so much.
John
David Fisher
Try my favorite formula, the foundation for structural engineering:
Hooke’s Law:
“as the extension, so the force…”
David L. Fisher SE PE
Fisher and Partners - Cayman
372 West Ontario Chicago 60610
75 Fort Street Georgetown Grand Cayman BWI
319 A Street Boston 02210
312.573.1726 facsimile
312.622.0409 mobile
john yang
Thank you so much.
John
David Fisher
Hooke’s Law is bascially F = k*x
F, I assume you know.
x = say 0.1” just to pick a value, solve for “K” which is your spring constant.
Not sure what your structure/foundation type is or load magnitudes…
That’s a good place to start, if the results don’t make sense, then reduce the value of “x” as necessary
To make the results reasonable.
The bigger question might be, why are you modelling this condition this way?
AISC has spent years developing the base plate design criteria.
Can’t you just use that design procedure?
john yang
Depending on spring constant, it will change tensions on the anchor bolts. If somebody starts with no idea of bolts' tensions, they may come up with very small number if they use very flexible springs.
Anyway, the reason that I am modeling the base plate instead of using AISC design guide is my base plate has re-entrant corner inside and have both direction lateral loads (of course both direction shears and moments) at the same time.
I want to know how much stress concentrations at the re-entrant corners are and I don't think AISC design guide covers this situation.
Thank you so much.
John
William Haynes
Wesley Werner
Wesley C. Werner
From: Wesley Werner [mailto:wwe...@conewago.com]
Sent: Friday, January 30, 2009 2:55 PM
To: sea...@seaint.org
Subject: RE: Concrete Spring Constant for Base Plate Modeling
Wesley C. Werner
Wesley Werner
Wesley C. Werner
jwh...@megr.com
Wesley, that was a great link. How can I get more like that?
- Jeremy
Quoting Wesley Werner <wwe...@conewago.com>:
> magnitudes...
>
>
>
> That's a good place to start, if the results don't make sense,
> then reduce the value of "x" as necessary
>
> To make the results reasonable.
>
>
>
> The bigger question might be, why are you modelling this
> condition this way?
>
> AISC has spent years developing the base plate design criteria.
>
>
>
> Can't you just use that design procedure?
>
>
>
>
>
>
> ________________________________
>
>
> From: john yang [mailto:jeon...@gmail.com]
> Sent: Friday, January 30, 2009 12:38 PM
> To: sea...@seaint.org
> Subject: Re: Concrete Spring Constant for Base Plate Modeling
>
>
>
> How can I assume "the extension"? For spring, k=EA/L I know E
> and I know A and I know concrete compressive strain (0.003). The
> problem is L or deltaL. How can I assume those? Will L be full length
> or depth of member? How much will I assume delta L for it?
>
> Thank you so much.
>
> John
>
> On Fri, Jan 30, 2009 at 9:31 AM, David Fisher <dfi...@fpse.com>
> wrote:
>
> Try my favorite formula, the foundation for structural
> engineering:
>
>
>
> Hooke's Law:
>
>
>
> "as the extension, so the force..."
>
>
>
>
>
>
>
>
>
> David L. Fisher SE PE
>
>
>
> Fisher and Partners - Cayman
>
> 372 West Ontario Chicago 60610
>
> 75 Fort Street Georgetown Grand Cayman BWI
>
> 319 A Street Boston 02210
>
>
>
> 312.573.1701
>
> 312.573.1726 facsimile
>
> 312.622.0409 mobile
>
>
>
> www.fpse.com
>
>
>
>
> ________________________________
>
>
> From: john yang [mailto:jeon...@gmail.com]
> Sent: Friday, January 30, 2009 11:29 AM
> To: sea...@seaint.org
> Subject: Concrete Spring Constant for Base Plate Modeling
>
>
>
> Hi,
> I am modeling base plate on the 6000 psi concrete column and I
> want to put concrete compression only spring to represent concrete. The
> problem is what is the compressive spring constant of concrete. Could
> you help me to get it?
>
> Thank you so much.
>
> John
>
>
>
>
>
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Harold Sprague
I would suggest the procedure in Omer Blodgett's "Design of Welded Structures". It accounts for the stretch in the anchor rods and the strain in the concrete. As with all of his work, it is very logically presented and well thought.
It is easily presented in a MathCAD template.
Regards, Harold Sprague
Date: Fri, 30 Jan 2009 11:22:07 -0800
Subject: Re: Concrete Spring Constant for Base Plate Modeling
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Wesley Werner
Wesley C. Werner
-----Original Message-----
From: jwh...@megr.com [mailto:jwh...@megr.com]
Sent: Friday, January 30, 2009 11:34 PM
To: sea...@seaint.org