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Re: 3-D modeling

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Steve,
 
        I have seen two anchor bolt failures in my career.  Both were the result of (in my opinion) bad design combined with thermal loading.
 
        One was a two span bridge for light rail transit system.  The bridge was a two span box girder with anchor pins which could only resist shear.  During construction a spring snow storm (which left the top deck covered in snow, hence cold) combined with a warm spring sun following the storm (which left the side and bottom chord warm) resulted in a sliding end lifting above the pins.  The bridge then slid off the piers and landed upside down in the river.  A hand full of nuts would have prevented this failure as would the train rails had they been installed.
 
        The other failure involved a rail used to tie down a window washer's scaffold.  The design called for the rail (standard I beam 4" deep I think) anchored to the concrete roof slab with the roof insulation coming into the side of the rail.  After all approvals and site reviews were completed "someone" decided that the rail should be well above the roof insulation so 6" by 6" piers about 3 to 4 inches high were added (not only without EOR knowledge approval but without reinforcing as well) and so it was constructed.  Subsequently, someone decided to use the scaffold for bricklayers to work on the facade; they stacked a load of brick on the scaffold and it landed on the sidewalk four or five stories below.  It was discovered that thermal forces had almost totally destroyed the unreinforced pedestals.  Unfortunately, the person responsible for the bad design did not go down with the brick; fortunately, no one else did either; and there was no one on the sidewalk at the time.  The rails were reinstalled using bolts through the slab.
 
Regards,
 
H. Daryl Richardson
----- Original Message -----
Sent: Wednesday, January 16, 2008 11:25 AM
Subject: Re: 3-D modeling

Good morning,
 
Have you guys noticed that - on top of a ridiculously complicated procedure per ACI 318-05, you cannot really design a reasonable anchor bolt anymore
(IBC/CBC 1908.1.16)?  The problem is that we really DID NOT HAVE ANY ANCHOR BOLT FAILURES TO TALK OF!
 
V. Steve Gordin, SE
Irvine CA
----- Original Message -----
Sent: Wednesday, January 16, 2008 10:14
Subject: Re: 3-D modeling

In a message dated 1/16/2008 7:09:00 A.M. Pacific Standard Time, Tom.Hunt(--nospam--at)fluor.com writes:
Conrad,

You completely forgot about Al Core requiring government funding to study ant farts contribution to global warming.

Thomas Hunt



"Conrad Harrison" <sch.tectonic(--nospam--at)bigpond.com>
01/15/2008 08:08 PM
Please respond to seaint
To
<seaint(--nospam--at)seaint.org>
cc
Subject
RE: 3-D modeling





What put it in the code! Now that's a bad idea!

First have to provide an exact specification for the type of honey to be
used and the species of ant. Then provide funding for a phD so that can
determine the best combination of honey and ants to generate the maximum
pain.

Then conduct an economic study, to see if the required specification of
honey and ants are readily available to all. Reduce the performance criteria
to allow more commercially available honey and ants to be used.

Then it will need reviewing against occupational health and safety
requirements to ensure that pain can be inflicted without causing undue harm
or violating human rights.

Then people will want to be innovative and adopt alternative solutions, so a
performance based criterion will be required. A complex but cheap
mathematical model will be developed, to avoid expensive testing; this will
permit assessing the performance of alternative solutions: say eucalyptus
leaves and a rogue koala.

Then we need an extra level of regulators to enforce the codified abuse of
plan reviewers, since they won't enforce it on themselves.

Once adopted in the code. People will continue doing what they have always
done, declaring they've been doing it this way for 30 years without
problems. Or the whole idea will be considered too complex, and people will
abandon the concept altogether. Once it falls into disuse the code writers
will delete it from the code as obsolete. Some five or so years later, it
will be perceived as an innovative new idea, and there will be moves to put
it back in the code, with an improved system of enforcement promised.

So if you put it in the code it will just become too cumbersome to be
practical. Or it will be taken to with enthusiasm and plan reviewers will
become a rare and endangered species and the whole regulatory ecosystem will
collapse. :-)



Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.tectonic(--nospam--at)bigpond.com
Adelaide
South Australia
-----Original Message-----
From: Bill Allen [mailto:T.W.Allen(--nospam--at)cox.net]
Sent: Wednesday, 16 January 2008 12:34
To: seaint(--nospam--at)seaint.org
Subject: RE: 3-D modeling

O.K., so when is this provision going to make its way into the code?

:o)

T. William (Bill) Allen, S.E.
ALLEN DESIGNS
Consulting Structural Engineers


> Also in my opinion there would be no benefit to doing a 3-D finite element
> model for 1600 square foot two story snoopy house with 2' simpson strong
> wall
> garage front piers and if a plan reviewer makes you do one then they
> should
> be smothered in honey and thrown on an ant hill.


And we all know how deadly those Farts! can be........
 
Joe Venuti
Johnson & Nielsen Associates
Palm Springs, CA




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