beam with uniform loading supported at 4 corners

nmk15

Hi
I have a wood beam (that has a width w , and a length L ) supported at 4 corners. A uniform load of wt lb/ft covers the entire top surface area of the beam. each corner has a structural tubing steel. when performing stress and loading analysis, how can I simplyfy the above to be a beam supported at two ends? is there any example or toturials that covers beams supported at 4 corners and the stress and loading analysis explained. ****this is not a homwwork problem ***
thanks

PhanthomJay

I'm not sure what you mean by 4 corners. Is the beam 'sandwiched' at each end in between 2 steel tubes at the top and bottom faces of the beam, or is this a very wide beam (flat plate, like a sheet of plywood) that sits on 2 tubes at each end, on the near and far corners of each edge?

minger

My understanding is that there are 4 cylindrical beams supporting the plate at all four corners. If so, then I really think you'll need to do some FEM on it, there will not be an accurate closed-form solution to this. Depending on the geometry, there will be stress concentration factors at the supports, and it would be difficult to model it as something simpler.

FredGarvin

It sounds like the OP is actually a plate that is supported at each corner by a column.

The simplification will all depend on what the dimensions of the original "beam" are. The word "beam" takes on a very particular definition in mechanics of materials versus a plate.

nmk15

sorry for the delay, I THOUGHT NO BODY WILL REPLY TO MY THREAD..
The wide wood beam consists of :
a wide sheet of wood 3/4 in thick with a length = 23 ft and width = 16 ft.
to bottom of this wood sheet, 27 (2 in by 12 in timber spaces 12 in apart) secured to it using wood screws.

steel beams :
I-beam: S 8X4 WITH WT PER FOOT = 23 LB
(A36 STEEL FY=36 KSI)
I-beam length = 23 ft
the I beam above is supported with one structural steel column tubing at both ends.

the square structural tubing: Fy=36 ksi and 12.02 Lb per foot
4in by 4in with 1/4in wall thickness.

the wood beam above is supported at only two sides, along the 23ft dimensions.
one i-beam and two structural tubing columns described above support the wood beam at the 23ft sides.
my goal is only to calculate : what is the maximum alloable load per square foot area.