huangyhg

solar panel support racks - design by aisc?
hi all,
i am working on the design of a short galavanized steel racking system for supporting solar panels. it is going to be constructed of w6x9's and hss 3x8 tubes, along with some 3x2 angle bracing. i have been designing according to aisc, however i am running into some problems with the range of adjustment i am going to need and i have a couple questions.
my first question is whether asic is the appropriate code to be using for this design. the reason i ask is my customer has shown me previous projects designed by other firms who have made connections that seem to be in violation of the asic code. for instance slots longer than a standard long slot which are oriented parallel to the direction of the force and made with a307 bolts. having this adjustment is very critical to him as it allows for him to adjust the racks to the landscape. i don't believe the previous firms ignored the requirements of aisc but rather there is some alternate code or exclusion somewhere that i am not aware of.
my second question is if there is not alternate code how do i allow for the large adjustments that will need to be made in the racking system since standard slots will not allow enough adjustment? i cant go with welded connections as the frames are galavanized and there are many connections so this would drive the cost of the project through the roof. is there anyway i can put in a longer slot and still be in compliance with aisc?
any suggestions?
thanks!
aisc's limitations and requirements are intended to provide guidance for main structural frames of a building and the direct supplements to such framing. this is an extraneous appurtenance that may require engineering judgment to deviate from the strict requirements of aisc or other codes.
the intent of such framing is to support the panels and to transfer the loads to the building in the sense of a component or cladding. for equipment such as this, i see no reason that you cannot engineer a minor deviation from the strict requirements of aisc as long as you have engineering justification for such and as long is it does not create a structural or safety compromise to the equipment, the structure, the occupants, or the public at large.
there's a good chance that the application doesn't require adherence to any particular code. in that case, you may want to refer to aisc for convenience, rather than starting from scratch, but need not adhere to every requirement.
note that the long and short slotted holes in aisc are intended for fit-up of permanently bolted connections, and not for adjustment slots for machinery.

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