Point Load Distribution

Does anyone know of a good reference that addresses the issue of distributing a point load out through a wooden deck through to the supports. I have a point load that is applied to a 4" thick deck supported on cross members spaced at 3' on centre and I would like to know what percentage of load I can assign to each support

 

[Trussdoc]

I assume that the deck is made up of beams or strips perpendicular to the supporting members; these would tend to act as simple beams rather than as a plate. Calculate the simple reactions (or possibly a three or four span analysis if the support beams form bays). The reactions should give you the plf load on the support beams. Of course, you have to include the deck design load as well.

Be careful of the locations of the ends of each strip; if you dont know the position of the point load with relation to the end of the strip, a simple beam calculation will be the safe way to go.

Tongue and groove decking could be a bit more problematic, but I would arbitrarily assume a beam width of 12 inches.

Also, make sure that the deck won't deflect excessively at the concentrated load.