Rotated Column (90 degree) in Top Level

Question

Rotated Column (90 degree) in Top Level

ALK2415 (Structural)

(OP)

11 Jan 24 18:34

Friend came to me asking for a structural solution for construction mistake, that some column were rotated (90 degrees)
my suggestion was to similar to below drawings. Also we i searched for others solutions found similar techniques
My question is there any other better solution
Would like to hear your opinions (Positive & Negative one) and thanks in advance ..
Note: only four (4Ø16mm form 12Ø16) longitudinal rebars were continuous for bottom level column to the top level column

other similar analogy solution:-

jayrod12 (Structural) · Answer 1 · 2024-01-11 20:43:32

I feel like that example solution you posted is actually meant to improve punching shear capacity.

ALK2415 (Structural) · Answer 2 · 2024-01-12 10:46:52

jayrod12
do have information about the shear-studs (threaded bars) capacity
i think whole idea is controlled by Fv of these bars (the blue dashed lines)
also i found similar idea, were they use it to lift bridge girder (below picture)

Also one more question, could we use post-tensioning method to increase the lateral confinement of RC columns ?

ALK2415 (Structural) · Answer 3 · 2024-01-17 11:05:58

There is something wrong here ?
why no one participate ?
may be someone (h*****l) red-flagged this thread ?

jayrod12 (Structural) · Answer 4 · 2024-01-17 16:27:12

Hi OP, you may be getting less traffic in this forum versus the main structural forum.

Regarding capacity of the anchors, I actually believe that installing thru-bolts in an existing column is a fools errand. There's usually so much reinforcing at the top of the column that getting them through without damaging reinforcing is near impossible.

I would likely be designing it based on epoxy or mechanical post-installed anchorage requirements.

ALK2415 (Structural) · Answer 5 · 2024-01-17 16:54:27

thanks jayrod12
"Installing thru-bolts in an existing column is a fools errand", might be justified for cost effective ?
Don't you think its more effective (stronger) than epoxy or mechanical anchorage ?

jayrod12 (Structural) · Answer 6 · 2024-01-17 17:12:04

Probably, but there's no published literature for thru-bolts as far as I'm aware. This conversation has been had a few times, more geared towards masonry but sometimes in concrete, due to the bending of the rod in the hole you end up with some fairly substantial bearing stresses right at the start of the hole.

I'm probably not the guy to wax intellectual on it though. I just know how I'd design it if I were doing it.

ALK2415 (Structural) · Answer 7 · 2024-01-17 18:39:57

I think will do it using ABAQUS and see how it goes (up to failure)
Also assuming some tolerance (0.5 mm) between the rod and the drilled hole
just to understand the mechanism.
This site is full with smart ppl, but unfortunately they are non-responsive in FEM when we ask a question

BFstr (Structural) · Answer 8 · 2024-01-26 12:25:49

OP,
How old is your building?
What is the building a multi story garage?
How many total stories and what floor this column is located on?
Are you in high seismic region?
What are the deminsions of lower and upper columns?

ALK2415 (Structural) · Answer 9 · 2024-01-26 13:43:38

Hi Bfstr and thanks for your help
- Building has 4 stories, wu = 12-15 KPa (ultimate loading)
- column dimensions 600x300 mm = (24x12 ") - note both column has same dimensions and only
Note: only four (4Ø16mm form 12Ø16) longitudinal rebars were continuous for bottom level column to the top level column

- this incidence done someone else due to Architectural engineer (allegedly)
- the building is new construction may be one month old
- seismic region is mid-high intensity (S1= 0.1 & Ss= 0.55)

BFstr (Structural) · Answer 10 · 2024-01-28 17:25:05

RE: Rotated Column (90 degree) in Top Level

BFstr (Structural) 28 Jan 24 17:25

BFstr (Structural) · Answer 11 · 2024-02-02 11:39:51

RE: Rotated Column (90 degree) in Top Level

BFstr (Structural) 2 Feb 24 11:39

Did you get it fixed?

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Rotated Column (90 degree) in Top Level