Absorption of force by beam
I would like to start by saying hello to everyone and thanking you for this amazing forum.
I am presented with an issue at work an am hoping I might get some help here.
I have a 12' X 24' table placed inside of a negative pressure environment. During testing the pressure will reach -500PSF (pulling upward on the top table surface) during the most extreme circumstance. The table is constructed on five(5) 6W20 beams placed 6' OC going across the 12' span. They are secured on the ends to a fixed point on the table and in the center they are secured to one(1) 6W-20 beam spanning the 24' length. The load is evenly distributed across the entire 288ft˛ of the table surface.
My question has two parts. The first part is, does the assembly (beam structure) absorb any of the 144000lbs of uplift force and if so, how would I calculate that. The second part is, what is the maximum uplift force that the 24' center beam would exert on anchors (holding it to the floor) from below (total number is acceptable).
My initial thought was to spread the load over the 3 linear supports (two side and center) and divide by 3, giving me 48,000lbs/beam Then it occurred to me that the load being transferred to the anchors would most likely be decreased due to the beam "absorbing" the load. Is this idea completely out in left field?
Thank you in advance for your assistance.