this is my first post
I'm close to start building my first home as an owner builder. I've done all the design and finally got my structural plans.
I find it hard though to get answers from the engineer and often enough "dimensions" are not mentioned on the plans, even some paper work was missing at first and sometimes everything seems a bit chaotic etc. So I thought I might put up some questions into this forum in the hope to find some answers and maybe it might help others later on as well?
My design is a steel frame house on poles (on a steep slope)
1. The design asked to put some of the RHS bearers on 12mm angles. I still haven't fully understood why the angles are not facing 180degrees (basically upside down) so the bearer sits on the "meaty part of the angle". I was told this configuration would weaken the angle and I would have to weld the whole bearer to the column then: (the explanation in red is from the engineer)
The whole question came up when I couldn't find a technical drawing of those steel angles to see how "thick" that meaty-corner part is so I can exactly determine the length of the bearers! I suppose they can't just sit on that round corner. (bottom pic) And again there was no info in the plans about the angle size, besides that they are 12mm thick. So I thought why not putting them the other way around and make the bearers touching the column...or at least so they are almost touching them, not sure if an expansion gap is advisable? (like the bottom picture on top)
2. Does anyone know why there is usually a gap to the bearer when installing C-channels (purlins)?
I do understand the gap is there to keep the gap the same as the thickness of the bottom plate of a column. (so the floor is even)
But is there another reason? When I look at other houses, they don't even seem to use cleats welded onto the bearers, instead they just use angles bolted into the bearers and into the joists which are then sitting directly on the bearers? *no gap* ?
Would appreciate any input
*thanks