All this talk about the exception I think I understand, but want to make sure. So my foundation should be sized for my regular load combinations (no overstrength, no capacity design per Seismic Provisions), then I can design my columns + anchorage using the maximum overturning resistance the...
Apologies if I was unclear before, I'm still using capacity design requirements to design my braced frame. I was just stating that I am using the overstrength as well and taking the greatest strength required for each component from all my load combinations and capacity design requirements of...
Thank you everyone for your responses. It was my strong suspicion that I needed to account for this in my anchorage. Not great news, but good to have the proper path forward. Per ASCE I will be using my overstrength Seismic in LRFD Load Combos 6 and 7 to design everything from my diaphragm down...
I'm designing a small building in a SDC D. The layout will include two Special Concentrically Braced Frames in one of my orthogonal directions but the loads applied to these frames end up being rather small (one story building, no rooftop equipment, steel roof deck no concrete). Design of my...
Whoops! Thanks for setting me straight on the moment of inertia! Alrighty, Basically if I set that spreadsheet to sum moments about the resultant, my moments applied will be zero (basic statics) and my footing is still entirely in compression. The Moment of Inertia issue explains why I was...
Alrighty,
So thank you all for the input.
Celt83: I looked at your spreadsheet (very cool), I moved the load application point to where my resultant is then recalculated my moments based on the full load of my footing + column load at the resultant. This makes more sense to me rather than...
The kern is a geometric property and should be independent of the loading. I was under the impression that tipping was not possible if the resultant of all loads lay within the kern, as the whole footing would be engaged in compression.
I see the logic there, but I guess my rationale is...
Thank you all for your responses. I've attached one of the more extreme cases. As you can see I have a column 9" away from the corner in both directions and have sized the footing such that the centroid falls just within the kern. Any knowledge or advice would be greatly appreciated. I know it...
Hello,
So I've recently started working on the design of some unique footings with columns largely off center due to the construction occurring in an existing building (our client wants to continue operations in the adjacent parts of the building, so along walls and in corners columns have...
So if I'm understanding this right:
If a load comes in at any angle other than parallel to a shear wall, that shear wall will resist a portion of the load based on the angle the force comes in at. We resolve the incoming force into a force parallel to the shear wall in question and a force...
I am running into an issue analyzing a structure that will have non-orthogonal shear walls. I figure that for a rigid diaphragm I could use the projected length of my walls in my primary directions to approximate their stiffness and distribute my loads that way, but for a flexible diaphragm...
I'm on the verge of starting a building addition in a Class C seismic zone. The existing building is quite large and complex and the as-built information
available is not complete. We have opted for separating the building addition from the existing building in order to eliminate the need to...
