STRENGTH OF HOOK
STRENGTH OF HOOK
(OP)
Hi ,
The shear from anchor bolt is transferred to stirrups and in some case the shear anchor bolt is transferred to the hook of stirrup,
It is either the strength of stirrup in tension or the hook embedded in concrete which ever is the minimum is the shear capacity of stirrup. But can any body explain how to calculate 135 degree and 90 degree hooLinkk capacity. please see the pic attached
The shear from anchor bolt is transferred to stirrups and in some case the shear anchor bolt is transferred to the hook of stirrup,
It is either the strength of stirrup in tension or the hook embedded in concrete which ever is the minimum is the shear capacity of stirrup. But can any body explain how to calculate 135 degree and 90 degree hooLinkk capacity. please see the pic attached






RE: STRENGTH OF HOOK
RE: STRENGTH OF HOOK
My code allows 90 tie hooks but, in this situation, I'll usually detail 135 hooks for exactly the same reason that you're concerned about it. I've never seen an capacity evaluation method presented for hook capacity. Some folks will say that 90 degree hook capacity can be estimated by comparing the development lengths requires for straight bars and those required for hooked bars. I'm skeptical.
In general, 90 hooks seem to be considered sufficient if your cover concrete can be relied upon to remain in place. For application where the cover will be lost, such as plastic hinges in seismic applications, 135 hooks are the way to go.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: STRENGTH OF HOOK
Please everybody share there views
RE: STRENGTH OF HOOK
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: STRENGTH OF HOOK
Actually in many cases the concrete inside the column remains in place through some number of cycles and is then itself lost... In the end you really only have the steel on steel. Japan and New Zealand now are developping special requirements for the tying of the rebar to ensure the stirrups remain in place and keep it all together. I'll try to dig up the relevant papers I have...
In the end this is not a hook capacity issue, but a stirrup remaining in place issue.
RE: STRENGTH OF HOOK