basic rebar strength question
basic rebar strength question
(OP)
OK, forgive me I don't currently have access to any of my concrete references. Its also been a while since I have had to do this.
I want to use rebar to develop axial tension of a drag strut into a concrete wall. Development length calculation is straightforward.
Then I get to the actual rebar strength. Now for Grade 60, yield stress= 60ksi. Can I simply factor my load and then:
rebar strength= Area of rebar x yield stress x 0.9 (tension strength factor)
I have also seen several tables that simply use yield stress of 60 ksi x area, which would be an allowable stress approach, which is what I think I have done in the past for concrete and masonry.
I included a link to a Simpson table for an example.
I want to use rebar to develop axial tension of a drag strut into a concrete wall. Development length calculation is straightforward.
Then I get to the actual rebar strength. Now for Grade 60, yield stress= 60ksi. Can I simply factor my load and then:
rebar strength= Area of rebar x yield stress x 0.9 (tension strength factor)
I have also seen several tables that simply use yield stress of 60 ksi x area, which would be an allowable stress approach, which is what I think I have done in the past for concrete and masonry.
I included a link to a Simpson table for an example.






RE: basic rebar strength question
RE: basic rebar strength question
The table is giving required embedment depth to develop the full bar strength, so in that case it would be unconservative to factor the bar strength down.
For your purposes you should do whatever the applicable design code tells you to do.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: basic rebar strength question
RE: basic rebar strength question
RE: basic rebar strength question
RE: basic rebar strength question
This method was called the Alternate Design Method and stuck in Appendix A of ACI 318-99. Before the Ultimate Strength Method, it was the "only" method in ACI 318.
RE: basic rebar strength question
Every rebar in tension that you design in a beam is assumed to be stressed at yield. Why is this situation any different? The rebare doesn't know if it's in a member that is subject to bending or direct tension. All it knows is that it's in tension.
RE: basic rebar strength question
RE: basic rebar strength question
pe consultant is correct, as you are in your original post. You analyze the rebar using (phi)x(fy)x(area of steel) using factored loads.
RE: basic rebar strength question
My original thought was confirmed:
rebar strength= Area of rebar x yield stress x 0.9 (tension strength factor)
RE: basic rebar strength question
RE: basic rebar strength question
See thread167-215126: ACI 318-08 and work stress alternate design methods
RE: basic rebar strength question
DaveAtkins
RE: basic rebar strength question
Irrespective of what method you use, there is more to the design than you have indicated. For example, you must properly develope the bar in the concrete (depends on the concrete strength, whether there is >12" concrete below, and other factors) and so on.
RE: basic rebar strength question