Development Length
Development Length
(OP)
Folks,
I have a question that may come across as retarded, but I gotta ask.
A standard hook for a #4 bar is 12 db = 12*0.5=6".
What happens for a #4 U bar or a #4 stirrup? Is the requirement that you need 2 * standard hook = 24 db to develop the bar?
I have a question that may come across as retarded, but I gotta ask.
A standard hook for a #4 bar is 12 db = 12*0.5=6".
What happens for a #4 U bar or a #4 stirrup? Is the requirement that you need 2 * standard hook = 24 db to develop the bar?






RE: Development Length
DaveAtkins
RE: Development Length
RE: Development Length
See ACI 7.1.
RE: Development Length
I guess I did not express myself correctly.
A quick sketch:
| |
| |
| |
|____|
?
What is the minimum length (based on db) of the horizontal leg of the U to develop this stirrup?
RE: Development Length
2" + 2(1/2" bar dia) = 3" total width.
RE: Development Length
Another question I have is this:
How much concrete should you have around a reinforcing bar in order to adequately transfer the stresses from reinforcing bar into concrete?
Assuming that you have a #5 bar, what is the minimum cylindrical area around the bar needed so that it does not pull out (precluding tension failure in concrete).
RE: Development Length
The australian code requires an increase in the development length of around 25% when there is more than 300mm of concrete below a bar (to allow for a void formed under the bar due to the slumping and shrinkage away from the bar of the concrete mass under)
I would assume the minimum cylindrical area is the minimum development length required by your code multiplied by the circumference of your bar
RE: Development Length
Assuming that you have a #5 bar, what is the minimum cylindrical area of concrete around the bar needed so that it does not pull out.
RE: Development Length
Read Chapter 12 of ACI. It explains the logic well.
The formula for development is based on the cover/spacing to the bar and the bar diameter. It is not expressed in terms of a cylinder of concrete required.