Simple Beam Calculation

Additional Assumption:

The opposite wall from the beam supporting the mezzanine is 13ft away.

Is the load (lb/ft) on the beam then 13*125 lb/ft^2 = 1625 lb/ft ?

No, it is 1/2 that, assuming the wooden beam ends are simply supported at the far end and where they rest on the steel beam.

According to my calc, with the lightest 8" x 8" universal column (46 kg/m, 31 lb/ft) and ends simply supported on the walls, max deflection ~ 2.4 mm and max stress ~ 25 MPa (3675 psi). Properties are I_xx = 4564 cm⁴ (110in⁴), Z_xx = 449.2 cm³ (27.4in³) need to check your's are similar.

125 lb/ft ~ 6 kN/m², in UK typically use 5 kN/m², so this looks OK, but depends what the room is used for.

Also if the 3' ends of the beam are built in to the wall, and the wall above is a reasonable height (you would need to decide what is reasonable!) the beam ends can be considered fixed and stress/deflection lower.

But picking up JohnDG's comments, you need to make sure you're happy with it before finalising.

Cheers......Codey

Sorry, but if you need to design something that could easily kill people if it failed, I'd advise you to go to a qualified design engineer, rather than risk getting some (possibly duff) information over the internet.

No offence intended to anyone on CR4.

John

This is not simply a simple beam calculation after all.

You have mentioned that the beam is loaded uniformly where in fact not. It also has to support concentrated loads from the wooden trusses perpendicular to it. The nature of support is also not simple.

My recommendation is for you to consult or seek the services of the right professional engineer.

I agree with the reponders:

There is a reason that structural engineers are licensed - to protect the health safety and welfare of the public.

You seem to be able to run through the calculations without really realizing why structural shapes are designed as they are and seem to be baffled at how to counter the deflection - which shouldn't exceed L/360 for your application.

Go chat with your friendly neighborhood structural engineer.