Seismic Classification of material conveyor

[jmurph36]

Hello everyone,

In the pictured that I have pasted to this message is a material handling conveyor that I have worked on. This conveyor is approximately 171 feet long and sits on lattice supports called bents that are concentrically braced. I am really struggling with how to classify the truss that supports the equipment and belt. I found an article from 2008 in Structure Magazine that states that these larger conveyors are generally considered "Nonbuilding Structures Similar to Buildings". If that is true, then looking in ASCE 7-10 Table 15.4-1, the only logical classification I can find is steel ordinary concentrically braced frames. Does anyone have any insight on how to classify the truss pictured in the attachment?

 

[r13]

In direction of the conveyor, you have a cantilever support system. You are correct in direction of the bent.

 

[ldeem]

I don't do a lot of seismic and it is rarely a controlling design case but I have used Table 15.4-2 All other self-supporting... (last one in the table).

Be careful what you pick because that can push you into special detailing requirements. In my case with low seismic loads it is simple to take a conservative approach (low R) and still have wind or belt pull control the design.

 

[HTURKAK]

If your conveyor system were supported on a floor of a building type structure, you could assume distribution system (similar to piping, ducts, conduits, cable trays ...). That is,could be modelled supported items in buildings.

In your case, the conveyor system supported on the bents .I could not see the exact picture , the right side of the picture (..EL. 5TH FLOOR ).

Will you provide a simple sketch showing the heights and location of the bents, lengths ..

IMO,the system could be modelled with a similar concept ( 15.5.5 Structural Towers for Tanks and Vessels ).

The major concern should be the effect of relative movement between supporting points..