To Be Sure...
Get it right: the ground shakes: the grillage moves sideways: the bin wall slams against the material: then the material rumbles about in the bin 
Most building codes provide seismic information.
■
Re: Seismic Loads On Bin Walls
You are right, most codes have seismic design criteria for the overall structural system but not the bin itself. For example, codes mention bins supported by braced or unbraced legs, not the bin walls.
It would seem that only one side sees thrust as the earth instantaneously moves in one direction. I would also be inclined to think of a large bin to be similar to a retaining wall. Any one wall in a bin is holding back a material that would act similarly to soil. I would think that something like an inverted triangular loading would be appropriate. However, some load should be taken by the bin bottom and sides in friction also.
Anyway, all the bin design books that I read are older and refer to other codes for seismic design but don't address the bin wall during seismic. I can only assume that this is ignored or my understanding of the dynamics of this situation is wrong.
Any advice? ■
The Plot Thickens.
During a seismic event the downloads do not markedly alter. Disturbance of the ensilage will cause it to assume different repose profiles within the bin. The internal friction of the material will determine the shift. Only the surcharge profile will alter during a seismic event. If you design for a chock-a-block full bin with no surcharge then you cannot exceed that condition during a seismic event.
If the bin is flat bottomed then the pressure profile can be factored to account for the lateral accelerations. If there is a tapered hopper it is likely that the lateral acceleration is insignificant compared to the pressure peaks encountered at the transition zone.
On the sidelines
: I have never seen thickener or classifier design work treated for seismic disturbance of the bed layers and pulp over-topping. Perhaps someone can enlighten us further? ■
Seismic Loads on Bin Walls
I have to design a bin with copper ore. I can calculate the static loads as per Gaylord & Gaylord. And Gaylord and other references even mention how to design the overall support structure for seismic. That is, guidance is given for column supports and bracing. However, nothing is mentioned regarding the design of the bin wall to account for material slamming against the wall during an earthquake.
Is this just ignored? Does anyone know of a reference that addresses this? ■