Miscellaneous Deck Questions

I was wondering if anyone could point me in the direction of any related rules and regulations when it comes to open deck trailer fabrication and support.

I'll be replacing my deck soon, and have a few unconventional ideas, but I'd like to be well read and informed before I start cutting into an expensive mistake and possibly save a few billable engineering hours.

The one subject I'm the least clear on is the regulation concerning engineering and mounting of load bearing surfaces below the main beams. Lumber racks and side boxes are fairly straightforward, but I'm looking to haul fairly dense product down there along with smaller LTL, so I'd like to be able to carry print outs of the rules with me in case I raise any eyebrows.

One last question I have concerns the recessed channels some steel haulers have between their main beams used as bracing for their beveled coil timbers. What are these commonly referred to as?

Thanks in advance for any help.

 

Thanks, rank, for the suggested reading. I'm aware of how to go about selecting beams, but I don't know what/if there is federal regulation on tolerance between yield/shear strength and WLL when it comes to selecting them, approved means of fastening, etc. I should have been more clear that I'm after the regulatory guidelines than engineering guidelines. (Edited OP to help reflect this)

I've had plenty welded/bolted onto/taken off the web over the years, and have started to notice the toll it's taking on the bow of the beams. I was actually interested in getting into the legal regulations to see if/how much weight upper and lower crossmembers would legally be able to bear from underneath (either laden or unladen from the top) and to what degree of tolerance in order to either avoid or lessen the extent to which the beams themselves need to be modified. Crossmembers are much more easily replaced or beefed up than main beams.