I need to design 40m high 13m dia stainless steel silo for severe
seismic zone. The silo is supported at its junction with hopper by
eight columns.
One can do a response spectrum analysis of silo+hopper+column
to find the distribution of loads along the height.
How does one find the effect of stored mass dashing against silo
wall during earhquake. Is the procedure similar to design of
retaining walls?
Thanks
Rudra Nevatia
Yes, does anyone have any reference for this subject? The tower design is in the codes. Need info for forces on walls of bin.
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Initially the silo wall will dash against the stored mass!
A realistic limit state would probably be where the ensiled material reaches the natural repose. That would involve morphing the top surface surcharge to an inverted cone with the apex on the wall, assuming sufficient material content. It would then be possible to calculate the material depth & any shift in CofG using a 3D graphics tool.
If the bin is nearly full then there might be spillage from overtopping, which could be as serious as minor structural failure.
There was reference to an excellent silo design text in this forum about 6 months ago. As I remember it the book is available from Amazon.com.
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A scale model loaded with the product mounted to a shaker tableOriginally posted by rudranevatia
I need to design 40m high 13m dia stainless steel silo for severe
seismic zone. The silo is supported at its junction with hopper by
eight columns.
One can do a response spectrum analysis of silo+hopper+column
to find the distribution of loads along the height.
How does one find the effect of stored mass dashing against silo
wall during earhquake. Is the procedure similar to design of
retaining walls?
Thanks
Rudra Nevatia
used to test seismic effect on buildings will work well and will proof the design or kill it either way.
Keep in mind every one point increase in the Richter scale is 100 times more violent than the last- I do not remember what the moment magnetude scaling is for quake violence/energy.
Eurocode 8 Part 4 deals with earthquake on silos.
However, this is a simplified approach.
Further details of solid-structure interaction for bulk storage can be found in following publication :
"DYNAMICS OF SOLID-CONTAINING TANKS" by Veletsos, Younan and Bandyopadhyay.
I found this publication a few years ago on the internet. Guess it must be still there somewhere.
It describes a method to reduce the product pressure on the wall by allowing a part of the horizontal force to be translated to the foundation by intergranular friction.
Stef R.
I understand that during seismic force, material shift will cause friction leading to compressive bending failure of shell. One has to calculate allowable bending compressive which will be quite low being 13 m dia with some 12 OR 16 mm shell plate thickness.
An extended research for eartquakes in respect to silos of the eurosilo type is done by mr L.A. van wijk.
The published book i am referring to is named :
Earthquake resistance of mammoth silos of the eurosilo type.
Maybe this book can help you with your answer.
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You could reduce seismic loading of your silos by doing away with hoppers and columns. Automatic reclaim and clean-up could be achieved by vibrating floors. See silexport.com
Rdgs
JC Poncet
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