Normal practice is to pour the Column first, stopping the pour an inch or so below the deck form. The column will shrink a little as the slab is prepared over the next few days.
If you pour the slab and column at the same time, you risk a crack at the top of the column when column shrinking...
My concern is that the time of instruction Champlain Towers South both 40 grade and 60 grade steel was available and commonly used.
Threshold inspection did not exist yet and the contractor sometimes bought 40 grade steel because it was cheaper.
Not saying it happened here , I would just like...
Did anyone ever find grade marks on photos of the column steel?
I can’t find any indication of 60 grade steel as specified in the drawings.
Sorry if I missed it.
Mojojohn
Does anyone know of any close up photos of the rebar so 60 grade can be verified?
I did not see 60 grade marks or double lines on the ones I saw.
The plans specified 60 grade. Was it?
Regards,
Mojojohn
What is a "trigger" and what is the "cause" of the collapse?
I propose that they may be two different things like the straw (trigger) that broke the camel's back (broken back is the collapse.)
I also feel that it is likely that the ground floor columns were degraded due to salt water exposure...
Engineers inspecting for damage to South Florida condominiums in the wake of the Surfside Towers South collapse should be aware that the only engineers allowed to inspect threshold buildings (Threshold building means any building which is greater than three stories or 50 feet in height, or...
CONFUSION?
Foundation drawings shows PIF's (pressure injected footings). Then call out 14 x 14 precast driven to 50 tons (100 kips).
14x 14 precast are usually driven to 75 kips and I doubt that they would ever be used at 100 kips in South Florida.
Likely Franki or other PIF's at 100 kips...
I have designed 100's of Post tensioned slabs and have always considered the 5000 psi limit (70 psi sqr f') to be the maximum Vc before using steel for Vs part.
I believe commentary discusses the reason is testing, but I don't have my ACI here.
You are stuck with about 5000 psi maximum for use in the concrete part of shear stress. 70 x 70=4900 psi
You may go up to 8 sqrt f'c with the addition of steel such as stud rails, steel sections or stirrup type reinforcing.
Though you may use concrete greater than 5000 psi for say transmission...
This is the rule we are required to follow in Florida.
61G15‐31.004 Design of Cast‐in‐Place Post‐Tensioned Concrete Structural Systems.
(1) Structural engineering documents shall show the complete structural configuration and loading requirements of the post‐tensioned system including: member...
I have always found that for small reasonable spans for a single family home, usually close. For large spans, the short answer is no unless you include work done by the sheathing.
Fought this battle with a large wood church 40 years ago. Put in a triple 2 x 6 top plate on 2 x 6 walls. They...
Jdonville,
Thank you for your suggestions.
When we design as columns we take into consideration soil support using the Lpile program or by estimating the unsupported length from soil borings. While we limit the cages to as short as reasonable, our piles are often under tension resulting in...
