huangyhg

seismic load on conveyor truss?
ok, asce 7-05 is giving me a headache again. i need to determine seismic loads on a steel box truss (single angle chords at 4 corners, single angle side verticals and diagonals, single angle diagonal "wind" bracing between top chords & sim between bottom chords). this truss is used in an exterior location and supports a conveyor system for bulk material handling. further, the truss has a walkway on one side for maintenance of the conveyor system.
so my question is - which section of asce 7 applies? on one hand, table 13.6-1 has a specific entry for "manufacturing or process conveyors (nonpersonnel)", which sounds good at first, but technically this is in the "nonstructural components" chapter, and my truss is definitely structural. also, the fact that they specify "nonpersonnel" leads me to believe this would apply more to the mechanical conveyor system itself, not the truss. the other possibility would be chapter 15(nonbuilding structures not similar to buildings), but table 15.4-2 doesn't have anything like a trussed bridge configuration. and i'd hate to resort to the "all other self-supporting structures..." provision with r=1.25 unless that's really appropriate.
so code gurus please advise!
personally, i'd design the conveyor support structure between the bents as "ordinary steel concentrically braced" with r=3.25
the support bents i'd design under "inverted pendulum" with r=2 since almost all the weight is at the top.

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