Question for steel erectors/engineers.

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As one does, I was checking out the little details of a building I was in. Standard prefab steel structure which is common for commercial builds here (Saskatchewan). I noticed the purlins were closer spaced in the corners. I attached a picture of the corner, you can see the normal spacing on the right and left side. You'll also see the extra purlins terminate after the beam and don't continue through the buildings length. This is in all four corners, and I can't think of why theyd be there, a...