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RE: fem & caissons

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The Florida DOT has a program called Florida Pier specifically designed to
handle pile groups and individual piles in nonlinear soils with axial and
lateral loads.  The URL is
http://www.dot.state.fl.us/structures/proglib.htm.  Try it.

I strongly echo Michael Valley's comments.  You DON'T want to model the
nonlinear response of piles with a linearly elastic program.  I've done
extensive analyses of laterally and axially loaded piling for offshore oil
and gas platforms.  Using a nonlinear FE or FD program is the way to go,
especially since good software (Florida Pier) is freely available.  Twenty
odd years ago when I first started doing that sort of analysis software
similar to Florida Pier (but without the Windows user interface)  was
licensed for upwards of $30K to $50K.  My how times change...

John W. Woollen, PE
Lafayette, LA
318/989-1722
jwoollen(--nospam--at)bigfoot.com




-----Original Message-----	From: Michael Valley [mailto:mtv(--nospam--at)skilling.com]
Sent: Thursday, May 13, 1999 1:45 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: fem & caissons


Mark:

It is probably not a good idea to try to base a lateral pile analysis
solely on RISA3D.  The lateral stiffness of the soil can be
significantly nonlinear, is sensitive to the properties of
various soil layers,  and even within layers varies substantially as
a function of the depth.  As a minimum, I would suggest using a
program like LPILEplus (or information from the appropriate NAVFAC
Design Manual) to understand the behavior of an individual pile.

If the work needs to extend to pile groups, then pile group
behavior can be calculated by methods described in texts (using group
factors, etc.) or it may be possible to make an appropriate linear,
3D FE model if the nonlinearity of individual springs is not
significant for the range of loads anticipated.  The individual
springs would be assigned properties to match the results of the more
involved single pile analysis (which is really the critical step).

-Mike

**********************
> Date:          Thu, 13 May 1999 10:20:00 -0700
> From:          "Mark D. Baker" <shake4bake(--nospam--at)earthlink.net>
> Organization:  http://www.seaint.org
> To:            seaoc <seaint(--nospam--at)seaint.org>
> Subject:       fem & caissons
> Reply-to:      seaint(--nospam--at)seaint.org

> Has anyone had success trying to model an embedded pile subject to
> lateral loads with Risa3d ? I know vertical load can be assessed for a
> spread footing modelling plate/shell elements but I'd like to try it
> with a round drilled, cast-in-place pile. Any body had success or
> failure with this they would like to share?
>
> Regards,
>
> Mark

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Michael Valley                                   E-mail: mtv(--nospam--at)skilling.com
Skilling Ward Magnusson Barkshire Inc.                  Tel:(206)292-1200
1301 Fifth Ave, #3200,  Seattle  WA 98101-2699          Fax:        -1201

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