Steel beam bearing in plane of a wall
What is the best way to support I beam on a cavity wall if the beam is placed in plane of the wall? And how to calculate correctly?
I'm considering common situation, UC203 steel beam on a cavity wall (lets say 100mm brick + 100mm cavity + 100mm 3.9N block).
I suggest three ways, and I would really appreciate if somene could give me comments about this ones or suggest something else:
1) bearing plate - steel plate same width as the wall
2) unreinforced two precast padstones on each wall leaf
3) unreinforced cast in situ padstone, width as the wall
My observation is that:
1) is probably a bit more expensive and more time consuming than 2) and 3), because this steel piece must be custom produced, but from structural point of view it is giving even stress distribution on masonry (I'm not sure if this plate can create cold bridge)
2) it is easy for installation, doesn't make cold bridge, but from structural point of view I'm afraid this can make moments due to eccentricity of the beam and later wall deflection, cracking etc.
3) not so easy for installation, requires formwork, pouring of concrete, concrete curing, can make cold bridge, but structuraly very solid
In sketch I made one question mark:
I need maximal value of L1-L2 or by words: I would like to know where I can cut the beam, as I assume it doesn't need to be up to the end of bearing plate/padstone, but I don't know how much exactly.
Probably in case of bearing plate, beam can be shorter because plate is very stiff compared to masonry and it will distribute load even when there is big 'cantilever' L1-L2
In case of concrete padstone, force is being transfered with 45deg angle, so I think L2 can be shorter than L1 for padstone depth.
And one more question:
Is there some recommendation for minimal bearing plate thickness. I know it can be calculated but is there some minimal value like 10-12 mm?