Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]


[Subject Prev][Subject Next][Thread Prev][Thread Next]
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.

Harold Sprague

-----Original Message-----
From: Stefan Reumers [mailto:Reumers.S(--nospam--at)]
Sent: Wednesday, February 15, 2006 6:58 AM
To: seaint(--nospam--at)

I have to design 24 aluminium silos 720 m3 each for the storage of granular

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

Any help would be much appreciated

Stefan Reumers

Engineering Silo Dept.

Ellimetal nv

Express yourself instantly with MSN Messenger! Download today - it's FREE!

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at:
* * This email was sent to you via Structural Engineers * Association of Southern California (SEAOSC) server. To * subscribe (no fee) or UnSubscribe, please go to:
* Questions to seaint-ad(--nospam--at) Remember, any email you * send to the list is public domain and may be re-posted * without your permission. Make sure you visit our web * site at: ******* ****** ****** ****** ******* ****** ****** ********