Horizontal Stiffener to increase beam shear capacity

[EngDM]

I'm referencing CSA S16:14 and I'm seeing that for Cl. 13.4.1.1 if you have a stiffened web you have different requirements. Firstly, is it referring to transverse vertical stiffeners or a horizontal stiffener? I've seen horizontal stiffeners used for web buckling but I have not myself specified it.

Is there a CSA reference example that one of y'all may have that would go horizontal stiffeners?

 

[KootK]

I do have a thought that I'm not quite confident in, but I don't think that sketch (or rather, the logic behind using the beam to restrain the column) reflects reality when we consider the beam's moment. Negative moment at the end of the beam (I assume there must be some that can't be neglected, if it's a moment connection in order to "restrain" the column) would be acting in tension top / compression bottom and rotate the column further in the undesirable direction rather than what is being intended.

I believe that I can defend the logic robustly. Consider how things unfold as the load on the column goes from minimum to maximum:

1) Load is below K=1 Euler. The rotation of the top of the column matches the end of the beam. So, as you say, the connection exerts a clockwise moment on the column.

2) Load is at K=1 Euler. Now the column cannot resist moments applied by the beam. So, briefly, the beam is truly pin ended. The connection exerts no moment on the column.

3) Load exceeds K=1 Euler. Outwards buckling of the column in K=1 mode is eventually brought to a halt by rotational restraint at the top of the column provided by the beam. The connection exerts a counter clockwise moment on the column which represents the restraint to the top of the column that allows it to be designed K=0.7.

So the moment in the connection reverses direction during the load history.

Obviously, some of this is approximate as things inevitably are when thinking in terms of bifurcation buckling. But I do believe that the basic logic is sound.

 

[EngDM]

Because normally the thing supporting a main floor is a foundation wall around the perimeter.

Building has a main floor parkade with wood perimeter walls.