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  1. catenaryworks

    Need little coding help

    k does have integer values: 1,2,.......,12. The y-axis of the plot generated shows them. n=12; d = 200; r = 3200; dbyr=d/r; theta=0:0.0001:2*pi; k=(n/(2*pi))*(theta+dbyr*sin(theta)); plot(theta,k) Thanks.
  2. catenaryworks

    Need little coding help

    No, not for school assignment.
  3. catenaryworks

    Need little coding help

    The code below plots 'k' along the y-axis and 'theta' along the x-axis. I would like help on the following, for which I do not know how to write out the code in MATLAB: 1. I want to extract only those 'theta' values corresponding to integer values of 'k' 2. Then, use the above 'theta' values...
  4. catenaryworks

    Definition of strain in cable structures

    Hello, I would like to know what definition of "strain" is used for CABLE ELEMENT by SAP. I am performing nonlinear analysis of cable-truss structures and am trying to write a Matlab code to compare with SAP results. I recognize that the source of discrepancy is probably in the definition of...
  5. catenaryworks

    SAP2000 3-hinge arch buckling

    Here's my SAP file. I will appreciate any help.http://files.engineering.com/getfile.aspx?folder=9f01e3be-5859-4b91-9ac3-4c7211fde922&file=ARCH_engtips.SDB
  6. catenaryworks

    SAP2000 3-hinge arch buckling

    What would be the suggested procedure in SAP2000 for determining the buckling load Pcr for this particular 3-hinged arch with loads as indicated in my previous message?
  7. catenaryworks

    SAP 2000 error

    I figured this out. It was because I had the analysis set-up to a 3D analysis while my model was 2D. Thanks for responding.
  8. catenaryworks

    SAP2000 3-hinge arch buckling

    Hi, Attached is the 3-hinged arch I want to analyze to determine at what value of P, the arch will buckle. Cross-section of the arch member: 5.5" x 30.25", E = 1800 ksi I have been using non-linear P-delta analysis and applying P in small increments. Is there an easier way to obtain Pcr...
  9. catenaryworks

    Honeycomb Dome

    Draw it in AutoCad and IMPORT it to SAP.
  10. catenaryworks

    SAP 2000 error

    Hello, I am performing an analysis of a prestressed cable-truss in SAP. On running the analysis, I obtain an error saying - "NULL GLOBAL DOF UY IS COUPLED TO A NON-NULL GLOBAL DOF AT JOINT 21 COSINE BETWEEN COUPLED DOF = 0.923880" Can someone help interpret this? Thanks
  11. catenaryworks

    SAP2000 3-hinge arch buckling

    I am unsure if I attachment is uploaded. Here are the geometry and material properties. Left support : 0,0 Left knee : 50 ft, 30 ft Ridge (hinge) : 100 ft, 40 ft Right knee : 150 ft, 30 ft Right support : 200 ft, 0 Cross-section of the arch member: 5.5" x 30.25" E = 1800 ksi
  12. catenaryworks

    SAP2000 3-hinge arch buckling

    Hello, I am trying to analyze a 3-hinge arch to find the buckling load. I have attached the SAP file here, which has the modeling done correctly. I suspect I am not doing to P-delta analysis correctly. My objective is to apply equal value point loads at the two knees and the top ridge...
  13. catenaryworks

    SAP 2000: Cable-Strut structures under self-stress

    Ishvaaag -- This was posted by Osquro to my question about opening files in other versions. His explanation is more elaborate and clear. Here it is ....... osquro (Structural) 15 Aug 11 9:57 Try using .s2k (or .$2k) file. Lets say that version 14.2.4 file was created in the computer A and...
  14. catenaryworks

    SAP 2000: Cable-Strut structures under self-stress

    According to BBWang's book page 28, such prisms are geometrically flexible and contain infinitesimal mechanisms. There is a mention about dumb elements used to make the structures geometrically rigid. We can then use the stiffness-method for analysis. SAP must be using Stiffness Method. Which...
  15. catenaryworks

    SAP 2000: Cable-Strut structures under self-stress

    Ishvaaag -- Open the .SDB file in Wordpad. Within the Wordpad file, search for PROGRAM CONTROL where the version number will be written. Change the version number from 15.X.X to 14.X.X. Go to your version 14, then to FILE, then Import the saved Wordpad file. It should open now. I could open...
  16. catenaryworks

    SAP 2000: Cable-Strut structures under self-stress

    Ishvaaag, Can you post your .s2k files instead of your .sdb for all the above that you sent. .s2k can be opened in older versions.
  17. catenaryworks

    Open older version files in a later version

    How do you open SAP 2000 v14.2.4 files in v14.1.0?
  18. catenaryworks

    SAP 2000: Cable-Strut structures under self-stress

    Ishvaaag -- Thanks so much for your thorough responses. I will try to figure out how I can open your SAP files and work with your messages.
  19. catenaryworks

    SAP 2000: Cable-Strut structures under self-stress

    ishvaaag, Your MathCad solution is very instructive. Thank you again. I understand that you use temperature change for changing the tendon lengths to eventually achieve the equilibrium configuration. The analytical solution, like your MathCad results, gives alpha=30. From your message on "6...
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