ajk1
Structural
- Apr 22, 2011
- 1,791
This question is addressed particularly to structural engineers who are experienced in seismic design, though all knowledgeable responses are welcome.
I ask the following question in relation to a set of company typical details that I am reviewing, and not in relation to any particular building project.
CSA Standard A23.1 calls for circular ties for tied columns to be terminated in a standard 90° hook. The question has been raised in the office as to whether this should be a 135° hook if in seismic area. I do not think so, because the hook extends into the interior of the column, and so is not subject to loss of bond on the hooked part, due to loss of cover concrete in a seismic event (so this is different than the hook of a beam stirrup). Since I would expect that it is easier to fabricate a rebar cage with circular ties with 90° hooks than 135° hooks, my preference is to specify the 90° hook including in seismic designed columns.
I ask the following question in relation to a set of company typical details that I am reviewing, and not in relation to any particular building project.
CSA Standard A23.1 calls for circular ties for tied columns to be terminated in a standard 90° hook. The question has been raised in the office as to whether this should be a 135° hook if in seismic area. I do not think so, because the hook extends into the interior of the column, and so is not subject to loss of bond on the hooked part, due to loss of cover concrete in a seismic event (so this is different than the hook of a beam stirrup). Since I would expect that it is easier to fabricate a rebar cage with circular ties with 90° hooks than 135° hooks, my preference is to specify the 90° hook including in seismic designed columns.
