Moment & Shear Consideration

[nicholi]

I am doing a design that involves the modification to an exsisting wood glulam beam in a canopy (3 spans, 2 continious & 1 cantilever). The column supports are being moved to new locations, thus the continious spans are increasing and the cantilever span is decreasing, so the glulam has to be modified for the additional loads. I am adding two 3/8" steel plates on either side of the beam, with a top and bottom staggered bolt pattern of 300 mm o/c. At the 6.9 m point where a column previously existed (it is now at 8.3m) there is splice in the glulam beam. I have checked the capacity of the steel plate to carry shear across that point and it is adequate. I have also checked the moment capacity at the point using the section modulus of the steel plates using only half of the plate depth (d = 494mm) for the value of h to be conservative and condisering that the plate will buckle in the top half (maybe third??) if it should fail in moment. The moment check also shows adequate capacity at that point.

In beam theory the web carries shear and the flange carries the moment. How do I appoach a steel plate carrying both loads at the same time? Would it be the same approach as for a column that carries both moment and axial load, do I check Mf/Mr + Vf/Vr <= 1.0? Do I modify the values of h for shear (area aviable to carry shear) and moment (section modulus)?

Thanks in advance for your feed back.

 

[boo1]

Why not utilize Mohr's circle of Von Misses stress analysis for combining the stresses.

 

[shaukii]

Use Modified h for shear and section modulus for moment. But make sure you consider local and global buckling of the steel plate.

I would use two wooden beams on either side of the (between supports not the cantilever) glulam if there is a space available to put.