Strut and Tie Help
Strut and Tie Help
(OP)
I'm trying to develop a strut and tie model for a beam connecting an overhead sign structure to a pair of drilled shafts. I'm having trouble developing the truss for the analysis. I've been following ACI publication SP-208 and SP-273 (Examples of Strut and Tie Models), AASHTO LRFD7, and Design of Reinforced Concrete by McCormac and Brown. All these publications show examples using the general truss configuration shown in the attached file. Is it correct that this truss is considered unstable? If so, how can it be used for design?
All the examples show symmetric applied loads, so the forces can be easily calculated. My problem does not have symmetric applied loads, so I am having trouble resolving the truss member forces. I have a few questions:
-Has it been so long since I have analyzed a truss that I'm completely out in left field?
-Does anyone have a recommendation for a truss configuration for my problem?
-Would it be appropriate to consider two separate analyses for my problem and use the more conservative rebar? This would use two symmetric loading cases(F1=F2=-50kips and F1=F2=120kips)
-Are the applied loads so close to the interior face of the drilled shafts that I don't need to consider a strut and tie model at all?
All the examples show symmetric applied loads, so the forces can be easily calculated. My problem does not have symmetric applied loads, so I am having trouble resolving the truss member forces. I have a few questions:
-Has it been so long since I have analyzed a truss that I'm completely out in left field?
-Does anyone have a recommendation for a truss configuration for my problem?
-Would it be appropriate to consider two separate analyses for my problem and use the more conservative rebar? This would use two symmetric loading cases(F1=F2=-50kips and F1=F2=120kips)
-Are the applied loads so close to the interior face of the drilled shafts that I don't need to consider a strut and tie model at all?






RE: Strut and Tie Help
Dik
RE: Strut and Tie Help
RE: Strut and Tie Help
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Strut and Tie Help
Dik
RE: Strut and Tie Help
Is this what you mean? If not, could you provide a quick sketch?
RE: Strut and Tie Help
Let me know what you come up with as we're all apparently still learning this program and I'm no expert on strut and tie to begin with. I was going to attach my cast file but the darn thing got corrupted. Apparently don't save it in the Program X86 folder as it wont actually save it without setting CAST to have admin privileges.
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Strut and Tie Help
RE: Strut and Tie Help
For the analysis of STM models I tendo to use Fachwerk, which also has a version for 3d models (although it doesn't check the nodes).
The link is the following: http://fachwerk.sourceforge.net/index_en.html
RE: Strut and Tie Help
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Strut and Tie Help
Thanks,
S&T
RE: Strut and Tie Help
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Strut and Tie Help
https://web.archive.org/web/20090903064452/http://...
RE: Strut and Tie Help
RE: Strut and Tie Help
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Strut and Tie Help