How would one appropriately design for heavy equipment loads on a concrete slab?
We have a grain storage building with a 4' reclaim pit over which a reinforced concrete slab will span. Is using AASHTO moment formulas (sections 18.104.22.168 & 2) and scaling for a 86 kip Payloader (with impact), appropriate? It seems the Payloader wheel distribution would be significantly different from a HS 20 truck. Using 3.30, Tire Contact Area, assuming 40 kip on each wheel, A = .01*40,000lb = 400 in^2, which gives length = 31.6" and width = 12.7" which seems in the ballpark...
Also, AASHTO 3.24.4, which states that shear would not need to be checked, seems to be a clearly inappropriate assumption to make in this particular situation. But what would the assumed shear distribution be, 12.7"?
Thanks in advance for any help.
Ed Fasula, E.I.T.