Derim01:
I can finally see your detail. That’s an interesting buckling problem and about the best I can offer is that you look at the development of width/thickness ratios and bucking vs. allowable compressive stresses, for unstiffened outstanding plate edges in compression. The various codes just don’t cover every possible detail with its own formula and design examples, yet; although it seems they are trying to do that and should have them all codified in another code edition cycle or so, and another 23 design guides.
I don’t happen to think that that buckling problem is the worst of your worries on the detail you have shown. I think you should look further at the following: (1) the two top chemical anchors always loaded in tension (epoxy creep over time) with the fatigue problems associated with cantilever tip loads of 1300kg or 1625kg, that’s 1.6tonnes at 38", right; (2) how are you really going to make your connection out at the monorail/canti. tip for shear, torsion and dynamic axial load parallel to the rail; and don’t forget those same loads in designing your cantilever; (3) what’s the funny little trapezoidal web piece at the bottom near the concrete wall for; (4) and finally, how do you make a good weld to the 16mm base plate on the wall without it just unzipping from the top due to the combined shear and tension stresses, the base plate flexure (prying on the weld) and poor weld termination conditions; you will have very high combines stresses in these welds right at their terminations? (5) The torsional loading on your 200x700mm concrete beam.
I would be inclined to fabricate those brackets out of thinner web material, but put top and bottom flanges, 50-75mm wide, or some such, on the web. These would act as stiffeners and allow for a proper weld to the base plate at the wall. You might make these by splitting a std. beam web diagonally, and adding the second (bottom) flange, or if you can resolve your buckling problem, maybe the bottom flange isn’t needed. You can also make these by cutting a std. beam to 950mm length, then cutting a triangle out of the web, near the bottom, but above the flg./web radius; then bending the bottom flange up and rewelding the web.
