Can you attach a picture or sketch of the beams?
Are these manufactured glulam beams?
There should be a stamp on them.
What I can do for this question is estimate the allowable bending stress and modulus of elasticity of the beams.
Is that reasonable?
Give me a couple days to look into these.
I would use no higher than a Fb = 1600 psi and E = 1300 ksi.
GB is the basic allowable bending stress. E is the modulus of elasticity.
What exactly do you need? A yes or no? Calculations?