Designing Rectangular Columns in STAAD Pro

I noticed that when we design a rectangular column, STAAD Pro always arrange the reinforcements as equal number on each face ? I ask the instructor who teach us at Bentley and he didnt have an answer.

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  • Not sure which code you are referring to. But for most codes, STAAD designs columns by placing equal number of bars on all 4 faces. For some codes like the Indian code, there is a parameter to specify if the bars should be just on 2 faces.

  • ACI-318-05 Code.I think that whatever you do, STAAD Pro can not handle unequal arrangement of bars.

    check this output file:

                ****************************************************

                *                                                                                    *

                *           STAAD.Pro V8i SELECTseries1                *

                *           Version  20.07.06.35                                    *

                *           Proprietary Program of                                 *

                *           Bentley Systems, Inc.                                   *

                *           Date=    OCT  3, 2010                                   *

                *           Time=    20:34:35                                          *

                *                                                                                     *

                *      USER ID: ***************************               *

                ****************************************************

        1. STAAD SPACE

        2. START JOB INFORMATION

        3. ENGINEER DATE 03-OCT-10

        4. END JOB INFORMATION

        5. INPUT WIDTH 79

        6. UNIT FEET KIP

        7. JOINT COORDINATES

        8. 1 0 0 0; 2 0 10 0

        9. MEMBER INCIDENCES

       10. 1 1 2

       11. DEFINE MATERIAL START

       12. ISOTROPIC CONCRETE

       13. E 453600

       14. POISSON 0.17

       15. DENSITY 0.150336

       16. ALPHA 5E-006

       17. DAMP 0.05

       18. END DEFINE MATERIAL

       19. MEMBER PROPERTY

       20. 1 PRIS YD 3.28084 ZD 0.984252

       21. CONSTANTS

       22. MATERIAL CONCRETE ALL

       23. SUPPORTS

       24. 1 FIXED

       25. LOAD 1 LOADTYPE NONE  TITLE LOAD CASE 1

       26. JOINT LOAD

       27. 2 MX 100

       28. PERFORM ANALYSIS

       STAAD SPACE                                              -- PAGE NO.    2

               P R O B L E M   S T A T I S T I C S

               -----------------------------------

        NUMBER OF JOINTS/MEMBER+ELEMENTS/SUPPORTS =     2/     1/     1

              SOLVER USED IS THE OUT-OF-CORE BASIC SOLVER

        ORIGINAL/FINAL BAND-WIDTH=     1/     1/      6 DOF

        TOTAL PRIMARY LOAD CASES =    1, TOTAL DEGREES OF FREEDOM =      6

        SIZE OF STIFFNESS MATRIX =        1 DOUBLE  KILO-WORDS

        REQRD/AVAIL. DISK SPACE  =     12.0/ 327276.8 MB

       29. START CONCRETE DESIGN

       30. CODE ACI

       31. MAXMAIN 10 ALL

       32. DESIGN COLUMN ALL

       STAAD SPACE                                              -- PAGE NO.    3

      ====================================================================

           COLUMN  NO.     1  DESIGN PER ACI 318-05 - AXIAL + BENDING

      FY - 60000  FC - 4000 PSI,  RECT SIZE - 11.81 X 39.37 INCHES, TIED

              AREA OF STEEL REQUIRED =   6.929  SQ. IN.

      BAR CONFIGURATION       REINF PCT.   LOAD   LOCATION   PHI

      ----------------------------------------------------------

       12 - NUMBER  7           1.548        1      END     0.650

      (PROVIDE EQUAL NUMBER OF BARS ON EACH FACE)                 ???????

      TIE BAR NUMBER    4 SPACING  11.81 IN

      ********************END OF COLUMN DESIGN RESULTS********************

       33. END CONCRETE DESIGN

       34. FINISH

  • For column design per the ACI code, STAAD offers only an arrangement that involves equal bars on all 4 faces.



  • I think this should be written beside the message :

    (PROVIDE EQUAL NUMBER OF BARS ON EACH FACE)

    by saying:

    Note that: For current release, STAAD CAN ONLY ARRANGE COLUMNS BARS AS EQUAL NUMBER ON ALL 4 FACES.

    in that way when STAAD somtimes said that there is no possible arrangemnet for bars, that not necessarlly lead to wrong design so one should increase the column size but one should check other arrangments that STAAD can not handle.

Reply
  • I think this should be written beside the message :

    (PROVIDE EQUAL NUMBER OF BARS ON EACH FACE)

    by saying:

    Note that: For current release, STAAD CAN ONLY ARRANGE COLUMNS BARS AS EQUAL NUMBER ON ALL 4 FACES.

    in that way when STAAD somtimes said that there is no possible arrangemnet for bars, that not necessarlly lead to wrong design so one should increase the column size but one should check other arrangments that STAAD can not handle.

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