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RE: UBC 97 - SEISMIC DESIGN GRANULAR SILOS

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According to the UFC 3-310-01

Iran
Isfahan Ss= 90.8; S1=36.3
Shiraz Ss=173.2; S1=69.3
Tabriz Ss=181.2; S1=72.5
Tehran Ss=205.0; S1=82.0

Shiraz appears to be about the closest to your site.

Regards,
Harold Sprague





From: "Stefan Reumers" <Reumers.S(--nospam--at)ellimetal.com>
Reply-To: <seaint(--nospam--at)seaint.org>
To: <seaint(--nospam--at)seaint.org>
Subject: RE: UBC 97 - SEISMIC DESIGN GRANULAR SILOS
Date: Mon, 20 Feb 2006 08:45:32 +0100

Harold

The silos will be installed in Bandar Imam, Iran. It's a port city on
the Persian Gulf.

Site conditions acc. UBC are the following :

Zone 2B
Soil Profile Type SD
Near source factors Na = Nv = 1

Regards
Stefan Reumers

-----Original Message-----
From: Harold Sprague [mailto:spraguehope(--nospam--at)hotmail.com]
Sent: vrijdag 17 februari 2006 19:52
To: seaint(--nospam--at)seaint.org
Subject: RE: UBC 97 - SEISMIC DESIGN GRANULAR SILOS

Stefan,
Let me know the location of your site.  I may already have the Ss and S1
for
your site, or at least get you close.  I do a lot of work in the Middle
East.

I would go with your somewhat conservative approach.  I see where you
are in
a difficult situation with the concrete base engineer being a different
entity.

Regards,
Harold Sprague





>From: "Stefan Reumers" <Reumers.S(--nospam--at)ellimetal.com>
>Reply-To: <seaint(--nospam--at)seaint.org>
>To: <seaint(--nospam--at)seaint.org>
>Subject: RE: UBC 97 - SEISMIC DESIGN GRANULAR SILOS
>Date: Thu, 16 Feb 2006 18:18:09 +0100
>
>Thanks again Harold for your quick reply.
>
>I'm aware of the shortcomings of the UBC-code, and I would very much
>like to make the comparison between UBC and ASCE 7-05, but here's the
>tricky part :
>
>The silos will be installed somewhere in the Middle-East, and there is
>no exact data available to make a spectral response analysis.
>Is it possible to translate the zone 2B of the UBC'97 to a certain
value
>of the spectral response acceleration according ASCE ?
>
>In addition, there's another problem :
>
>The engineering of the silos is our responsibility while the supporting
>structure will be designed by a Korean engineering company, so the
exact
>flexibility of this structure is still pending.
>Of course it is possible to estimate the flexibility and make an
>analysis of the combination of both silos and supporting structure.
>To my opinion however, the calculations will be conservative if we
>consider the supporting structure as having an infinite rigidity.
>
>Regards
>
>Stefan Reumers
>
>
>
>
>
>
>
>
>-----Original Message-----
>From: Harold Sprague [mailto:spraguehope(--nospam--at)hotmail.com]
>Sent: donderdag 16 februari 2006 17:00
>To: seaint(--nospam--at)seaint.org
>Subject: RE: UBC 97 - SEISMIC DESIGN GRANULAR SILOS
>
>Stefan,
>Given your constraints, treating the silos as nonstructural components
>per
>section 1632 should result in a more conservative design.
>
>I just get nervous when I see the UBC zones being used.  There were
many
>
>significant changes in the transition to the IBC.  Studies have shown
>that
>you can be very far off with base shear calculations when compared to
>using
>seismic specral ordinates.
>
>It might be worth a little extra time and see how your design would
look
>if
>you used the ASCE 7-05.  You don't have to tell your client, but it
>would be
>an intersting check.
>
>It is worth noting that the Veletsos paper is about the best document
>that
>there is on seismic design of silos and bins containing granular
>material.
>
>Another good document for reference is Tubular Steel Structures by
>Troitsky.
>   But the Veletsos paper is what should be used for seismic design.
>
>Regards,
>Harold Sprague
>
>
>
>
>
> >From: "Stefan Reumers" <Reumers.S(--nospam--at)ellimetal.com>
> >Reply-To: <seaint(--nospam--at)seaint.org>
> >To: <seaint(--nospam--at)seaint.org>
> >Subject: RE: UBC 97 - SEISMIC DESIGN GRANULAR SILOS
> >Date: Thu, 16 Feb 2006 09:01:44 +0100
> >
> >Thanks Harold,
> >
> >The thing about UBC'97 not being the most appropriate code for
> >calculating silos is exactly what I told our client but he would not
> >listen. So I am stuck with this code.
> >
> >The discussion now is wether or not to use section 1632.
> >
> >However trying to keep the wall-thicknesses of the silos within
> >realistic limits, I proposed to apply the Veletsos, Younan and
> >Bandyopadhyay-report (Dynamics of solid-containing tanks, prepared
for
> >the department of energy, Washington, D.C.).
> >This report allows for a part of the horizontal force to be
transferred
> >to the bottom (in our case the cone-cylinderjunction of the silo)
> >through intergranular friction.
> >For those who are interested in this report, it can be downloaded
here
>:
>
>http://www.osti.gov/bridge/purl.cover.jsp?purl=/453784-sUxqbN/webviewab
>l
> >e/
> >
> >This report also formed the base for parts of the new Eurocode 8 Part
4
> >(Design of structures for earthquake resistance - Silos, tanks and
> >pipelines).
> >
> >If any-one has experience with this method of design please let me
>know.
> >
> >Kind regards
> >
> >Stefan Reumers
> >
> >-----Original Message-----
> >From: Harold Sprague [mailto:spraguehope(--nospam--at)hotmail.com]
> >Sent: woensdag 15 februari 2006 20:31
> >To: seaint(--nospam--at)seaint.org
> >Subject: RE: UBC 97 - SEISMIC DESIGN GRANULAR SILOS
> >
> >It sounds like this is an attempt to use importance factors and the
>1997
> >UBC
> >to achieve a perceived higher performance.  I would suggest that you
>use
> >a
> >more up to date code like the ASCE 7-05 and perform a more
>sophisticated
> >
> >analysis.  Conservatism on loads does not necessarily buy you better
> >performance.
> >
> >Applicability of the UBC 97 to properly design granular silos is a
> >reach.
> >There were some adjustments made in the NEHRP that have been
reflected
> >in
> >the ASCE 7-05.  I would urge you to look at the ASCE 7-05 section
>15.3.1
> >and
> >15.3.2 which had granular silos in mind when it was created.  It was
in
> >the
> >ASCE 7-02 as well.
> >
> >Further, there has been coordination between nonstructural components
> >and
> >nonbuilding structures in the NEHRP / ASCE / IBC process to try to
> >account
> >for this as much as possible.  Not much was included in the UBC 97.
> >This
> >was in the early days of the nonbuilding structures effort.
> >
> >I would look at the relative stiffnesses of the aluminum silos and
the
> >concrete support structure.  I would also treat the contained product
>as
> >
> >just an impulsive mass.  We have looked at the potential of a
>convective
> >
> >component but there is not enough data.
> >
> >Regards,
> >Harold Sprague
> >
> > >
> > >-----Original Message-----
> > >From: Stefan Reumers [mailto:Reumers.S(--nospam--at)ellimetal.com]
> > >Sent: Wednesday, February 15, 2006 6:58 AM
> > >To: seaint(--nospam--at)seaint.org
> > >Subject: UBC 97 - SEISMIC DESIGN GRANULAR SILOS
> > >
> > >
> > >
> > >I have to design 24 aluminium silos 720 m3 each for the storage of
> >granular
> > >Polyethyleen.
> > >
> > >These silos are mounted on a 20 m high concrete structure.
> > >
> > >
> > >
> > >Prescribed earthquake code is UBC '97.
> > >
> > >
> > >
> > >Does Section 1632 apply or can I use Sections 1634 together with
> >Section
> > >1630 ?
> > >
> > >This makes quite some difference in the total lateral force.
> > >
> > >
> > >
> > >In addition, our customer asks for an importance factor of 1,50 as
to
> >my
> > >opinion granular storage silos would only require an importance
>factor
> >of
> > >1,0.
> > >
> > >
> > >
> > >
> > >
> > >Any help would be much appreciated
> > >
> > >
> > >
> > >
> > >
> > >Stefan Reumers
> > >
> > >Engineering Silo Dept.
> > >
> > >Ellimetal nv
> > >
> >
>
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