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RC Column stirrups 2
- Thread starter mar2805
- Start date
Yeah I'm with rapt. I'd bet the rebar monkeys prefer the detail on the left for rigidity of the assembly. The only benefit to the one on the right is the same sized stirrup for all, so you're saving a fabricator time (that he's not going to forward onto the project in terms of cost savings).
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- #4
JoshPlumSE
Structural
I disagree with Trenno. Once these are constructed, they should behave essentially the same. IMO, any difference is solely related to ease of construction or fabrication.
If the lap between the green and the blue links is sufficient, then yeah it would work.
But say you have 12mm links, then the lap length would be around 40*db = 480mm. You wouldn't space longit. bars further than 300mm in columns, more like 150mm. In this case (typical) the lap isn't achieved.
But say you have 12mm links, then the lap length would be around 40*db = 480mm. You wouldn't space longit. bars further than 300mm in columns, more like 150mm. In this case (typical) the lap isn't achieved.
- Thread starter
- #12
Of course?
Don't know where you are located as you didn't say. But many standards contain requirements for lapping stirrups in the cover concrete. For example this what NZS3101 has to say on the matter. A plain round bar has 2xbar development length in NZS3101.
Our standard is loosely based on ACI318, so you may/may not find similar provisions in ACI, to be honest haven't really looked. All I'm saying is these provisions exist for a reason, so investigate what your local standard has to say on the matter
Don't know where you are located as you didn't say. But many standards contain requirements for lapping stirrups in the cover concrete. For example this what NZS3101 has to say on the matter. A plain round bar has 2xbar development length in NZS3101.
Our standard is loosely based on ACI318, so you may/may not find similar provisions in ACI, to be honest haven't really looked. All I'm saying is these provisions exist for a reason, so investigate what your local standard has to say on the matter
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- #14
Of course it's different. But the requirements still require a full lap with hook turned into the concrete core under certain circumstances.
So where are you from, what does your code say on the matter?
I'm assuming you have loads in the long direction, correct?
So where are you from, what does your code say on the matter?
I'm assuming you have loads in the long direction, correct?
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- #16
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- #18
Yes your drawings contain closed stirrups, the hook (bend) around the bar going into the concrete is effectively the same as the extension on a standard hook in this scenario. The two extensions are the same bar with a closed stirrup.
The closed stirrups are fine, I'd do exactly the same. However the point is you may need the lap or overlap between the two separate closed stirrups to be sufficient to achieve a development length like the sketch I have marked up in the last post. I'm not sure how to articulate it any other way?
On the sides of the column where you have the stirrups overlapping, the overlap may need to be a code compliant lap (i.e. L_dh). This may depend on what standard you are working to, but either way it is a good detailing practice. If the bar is plain round bar, then it is usual that 2 times the standard lap for deformed bars is required.
I've asked twice now where you are from and what code you are working to so I can see if there is more specific advice in whatever standard you are designing to, can you let us know so someone can comment if there are similar provisions in that code?
The closed stirrups are fine, I'd do exactly the same. However the point is you may need the lap or overlap between the two separate closed stirrups to be sufficient to achieve a development length like the sketch I have marked up in the last post. I'm not sure how to articulate it any other way?
On the sides of the column where you have the stirrups overlapping, the overlap may need to be a code compliant lap (i.e. L_dh). This may depend on what standard you are working to, but either way it is a good detailing practice. If the bar is plain round bar, then it is usual that 2 times the standard lap for deformed bars is required.
I've asked twice now where you are from and what code you are working to so I can see if there is more specific advice in whatever standard you are designing to, can you let us know so someone can comment if there are similar provisions in that code?
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- #20
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