Staadpro checking

How to let staadpro only check member deflection but not check member strength(stability)?

  • Assuming you are using the latest AISC 360-10 code also known as AISC UNIFIED 2010 in STAAD.Pro, you can define a serviceability envelope and define a LOAD LIST ENV command to instruct STAAD to do deflection check for these cases. Here is an example
    ...
    DEFINE ENVELOPE
    1 3 ENVELOPE 1 TYPE SERVICEABILITY
    4 ENVELOPE 2 TYPE STRENGTH
    END DEFINE ENVELOPE
    LOAD LIST ENV 1
    PARAMETER 1
    CODE AISC UNIFIED 2010
    METHOD ASD
    DFF 240 ALL
    FYLD 46 ALL
    TRACK 2 ALL
    CHECK CODE ALL
    FINISH

    For more information on strength and deflection checks using AISCC 360-10, you may want to check out the following wiki article

    communities.bentley.com/.../20793.strengthserviceability-check-in-design



  • Hi, Sye

    Thank you for the reply . I knew how to direct staadpro to check member under specified load cases(combination)

    What i really wanted to know is how to forbid staadpro check member strength(stability), and only check and output deflection check result.

    see below picture.  is there a way to get that?

    Regards

     

  • Hi, Ryan

    I guess you have assigned Strength design parameters to beams, so Staadpro give you member strength check result.

    If you want to only check and output deflection check result, please set the format:

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

    **Load case for Deflection check**

    LOAD LIST ENV 1  

    PARAMETER 1

    ***check code**

    CODE AISC UNIFIED 2010

    METHOD LRFD

    **The DFF parameter is used to assign the allowable ratio of span/deflection. **

    DFF 900 MEMB 331 336 341 346 349 TO 393

    **The DJ1 and DJ2 parameters are used to identify the nodes at the extreme ends of the member to be evaluated for deflection. **

    DJ2 249 MEMB 354 358 361 364 367 370 373 376 379 382

    DJ1 245 MEMB 354 358 361 364 367 370 373 376 379 382

    ***Perform check code*

    CHECK CODE MEMB 331 336 341 346 349 TO 393

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

    The design result is:

    Answer Verified By: ryan li 

  • Xingmin:

    For your case, I think the deflection condition happened to be the critical ones, that is not correct all the time.

    See attached file of a simple frame model.

    I come to believe Staadpro will check member strength, no matter you provide strength design parameters or not.  Anyone can confirm this? or your defferent thinking.

    BTW, How to attach a file?

    Thank you

    STAAD PLANE
    START JOB INFORMATION
    ENGINEER DATE 26-Jun-14
    END JOB INFORMATION
    INPUT WIDTH 79
    UNIT METER KN
    JOINT COORDINATES
    1 0 0 0; 2 29.5 0 0; 3 0 11 0; 4 29.5 11 0; 5 14.75 11.7375 0;
    6 19.244 11.5128 0; 7 10.256 11.513 0; 8 5.128 11.2565 0; 9 24.372 11.2564 0;
    MEMBER INCIDENCES
    1 4 2; 2 3 1; 3 5 6; 4 5 7; 5 4 9; 6 3 8; 7 8 7; 8 9 6;
    UNIT MMS KN
    DEFINE MATERIAL START
    ISOTROPIC STEEL
    E 205
    POISSON 0.3
    DENSITY 7.68195e-008
    ALPHA 1.2e-005
    DAMP 0.03
    TYPE STEEL
    STRENGTH FY 0.2532 FU 0.4078 RY 1.5 RT 1.2
    END DEFINE MATERIAL
    CONSTANTS
    MATERIAL STEEL ALL
    *
    MEMBER PROPERTY AMERICAN
    1 2 TAPERED 1100 8 450 320 12
    5 6 TAPERED 1100 8 800 280 10
    3 4 TAPERED 725 5 500 250 10
    7 8 TAPERED 800 6 500 280 10
    UNIT METER KN
    SUPPORTS
    1 2 PINNED
    LOAD 11 DL
    SELFWEIGHT Y -1.1
    MEMBER LOAD
    3 TO 8 UNI GY -2
    LOAD 12 CG
    MEMBER LOAD
    3 TO 8 UNI GY -3
    LOAD 21 LL
    MEMBER LOAD
    3 TO 8 UNI GY -5.7
    LOAD 31 WLL1
    MEMBER LOAD
    2 UNI GX 3.1 8.8 11
    2 UNI GX 3.1 6.6 8.8
    2 UNI GX 3.1 4.4 6.6
    2 UNI GX 3.1 2.2 4.4
    2 UNI GX 3.1 0 2.2
    4 6 7 UNI Y 12.4
    3 5 8 UNI Y 8.1
    1 UNI GX 6.8
    LOAD 32 WLL2
    MEMBER LOAD
    2 UNI GX 8.1 8.8 11
    2 UNI GX 8.1 6.6 8.8
    2 UNI GX 8.1 4.4 6.6
    2 UNI GX 8.1 2.2 4.4
    2 UNI GX 8.1 0 2.2
    4 6 7 UNI Y 7.4
    3 5 8 UNI Y 3.1
    1 UNI GX 1.8
    LOAD 41 WRL1
    MEMBER LOAD
    1 UNI GX -3.1
    3 5 8 UNI Y 12.4
    4 6 7 UNI Y 8.1
    2 UNI GX -6.8 8.8 11
    2 UNI GX -6.8 6.6 8.8
    2 UNI GX -6.8 4.4 6.6
    2 UNI GX -6.8 2.2 4.4
    2 UNI GX -6.8 0 2.2
    LOAD 42 WRL2
    MEMBER LOAD
    1 UNI GX -8.1
    3 5 8 UNI Y 7.4
    4 6 7 UNI Y 3.1
    2 UNI GX -1.8 8.8 11
    2 UNI GX -1.8 6.6 8.8
    2 UNI GX -1.8 4.4 6.6
    2 UNI GX -1.8 2.2 4.4
    2 UNI GX -1.8 0 2.2
    *LOAD 61 EL
    *LOAD 62 ER
    *  *******************
    *    STRENGTH COMB
    *  *******************
    LOAD COMB 101 DL+CG+LL
    11 1.0 12 1.0 21 1.0
    LOAD COMB 102 DL+WLL1
    11 1.0 31 1.0
    LOAD COMB 103 DL+WLL2
    11 1.0 32 1.0
    LOAD COMB 104 DL+WRL1
    11 1.0 41 1.0
    LOAD COMB 105 DL+WRL2
    11 1.0 42 1.0
    *  *******************
    *    DEFLECTION COMB
    *  *******************
    LOAD COMB 201 LL
    21 1.0
    LOAD COMB 202 WLL1
    31 0.7
    LOAD COMB 203 WLL1
    32 0.7
    LOAD COMB 204 WLL1
    41 0.7
    LOAD COMB 205 WLL1
    42 0.7
    PERFORM ANALYSIS
    DEFINE ENVELOPE
    101 TO 105 ENVELOPE 1 TYPE STRENGTH
    201 ENVELOPE 2 TYPE SERVICEABILITY
    END DEFINE ENVELOPE
    LOAD LIST ENV 2
    PARAMETER 1
    CODE AISC UNIFIED 2005
    METHOD ASD
    DFF 180 MEMB 3 TO 8
    DJ1 3 MEMB 4 6 7
    DJ2 5 MEMB 4 6 7
    DJ1 4 MEMB 3 5 8
    DJ2 5 MEMB 3 5 8
    TRACK 2 ALL
    CHECK CODE MEMB 3 TO 8
    *
    *PARAMETER 2
    *CODE AISC UNIFIED 2005
    *METHOD ASD
    *FU 450000 MEMB 1 3 TO 8
    *FYLD 345000 MEMB 1 3 TO 8
    *BEAM 1 MEMB 1 3 TO 8
    *CB 0 MEMB 1 3 TO 8
    *STP 2 MEMB 1 3 TO 8
    *TRACK 2 ALL
    *LX 14.75 MEMB 3 TO 8
    *LY 3 MEMB 3 TO 8
    *LY 3 MEMB 1
    *LZ 14.75 MEMB 3 TO 8
    *LZ 16.5 MEMB 1
    **
    *UNT 1.5 MEMB 3 TO 8
    *UNB 3 MEMB 3 TO 8
    *UNT 4.5 MEMB 1
    *UNB 4.5 MEMB 1
    **
    *MAIN 200 MEMB 1 3 TO 8
    *DFF 1 ALL
    *LOAD LIST 101 TO 105
    *CHECK CODE ALL
    FINISH

  • It seems that you are trying to design tapered sections. Please note that STAAD cannot design tapered sections in the current version (20.07.10.66) as per AISC Unified design code. This feature will be implemented in the next STAAD.Pro version, which should be released soon. In fact, I have tested your model in the test version of the next STAAD.Pro release and noticed that only the deflection was checked of those tapered members and no strength checks were performed.



    Answer Verified By: ryan li