I would use #4 U-bars at 12" o.c. each way at bottom - hook at sides of drop panel to top of slab. I know it's more than required, but I integrate the compression steel in the I effective calculation and the rho prime calc (equation 9-11) to get a reduction of around 10% in long term total load...
Andrew,
A couple thoughts:
1. Since there is a contractor on board, then they have a p/t sub (the company that details and provides the tendons, and they also do the loss calculations). I would find out who that sub is and chat with their engineer on this subject.
2. Interior blockouts for...
It depends on a lot. Sounds like just an OCBF with tension-only bracing ... correct? In any case, I personally would prioritize the lateral system over the gravity system and run the double angle braces into a single plate gusset welded to the flange and centered on the web. I would also...
It will get pretty hot due to the curing and you will get cracks no matter what rebar you spec, but ... I would suggest a mix design that has retarders that slow down the cure rate, and I would suggest a misting or water spray to cool the mat slab as it cures to minimize those drying cracks.
Sometimes we do that at the contractor's request, since it allows him to get the correct elevation and layout after the concrete guys leave the area. The ss angles with ss anchor bolts should last as long as the building lasts.
You are asking a group of structural engineers who try like hell every day to get an architect to make decisions about all sorts of elevations and dimensions why another structural engineer doesn't have the info, and allege that he screwed up? Good luck!
As the owner to make the decision, since it is unlikely that corrossion of an interior protected steel post would corrode to a dangerous level before other deterioration was noticeable.
Never put structural load on veneer! With that said, if your drawing is to scale, the vertical load is insignificant in comparison to the veneer and the OOP load is just slightly more. But, look at uplift due to wind and how to transfer the moment? Show 2 horizontal steel angles aligned with...
So the "firewall" part is irrelevant now, ok, it's just a structural issue then... my guess is the precaster has anchored these free-standing walls with an anchorage detail very similar to the hold-down detail for a tilt-up wall. See tilt-up wall guidebooks. I've never seen a precaster provide...
4 hour firewall - structural cantilever - non conventional ... ok then. For the fire rating, you can check the IBC chapter 7 - it tells you minimum thickness based on material (cmu or conc.) and minimum cover to steel (more critical is you do go ahead and use p/t). For cmu, I would need an 8"...
The "firewall" part is curious ... 1hr, 2hr, 3hr, 4hr? Both get you the ratings, but you need a certain cover and you need 6" or more. The "p/t" part is structural, and not fire-related ...
What I would do is start by designing the posts for a minimum of 200# at 42". Then I would provide the cables at 4" o.c. (as you would with pickets, per code). Next, I would determine a reasonable pre-tension (or taut-ness), such as 100#, and then calculate the actual cable tension due to a...
