STAAD.Pro Help

V. AISC ASD - Select Wide Flange Beam 3

Determine an optimum section to carry a moment of 220 ft·kips plus its selfweight and spanning 35 ft between supports.

Reference

AISC Allowable Stress Design, 9th Edition,Example 10, page 2-147.

Problem

Fy =36 ksi

Cb = 1.0

Maximum unbraced length of compression flange is 15 ft.

Comparison

Table 1. Comparison of results
Result Type Theory STAAD.Pro Difference
Selected section W24x68 W24x68 none

STAAD Input

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\09 Steel Design\US\AISC\AISC ASD - Select Wide Flange Beam 3.STD is typically installed with the program.

STAAD SPACE AISC VERIFICATION PROBLEM FOR BENDING CAPACITY. PAGE 2-147
START JOB INFORMATION
ENGINEER DATE 22-Sep-18
END JOB INFORMATION
* OF 9TH ED. AISC-ASD. EXAMPLE 10.
* RATIO SHOULD BE APPROXIMATELY 1.0
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 35 0 0;
MEMBER INCIDENCES
1 1 2;
MEMBER PROPERTY AMERICAN
*TRIAL SECTION
1 TABLE ST W18X35
UNIT INCHES KIP
DEFINE MATERIAL START
ISOTROPIC STEEL_50_KSI
E 29000
POISSON 0.3
DENSITY 0.000283
ALPHA 6.5e-06
DAMP 0.03
TYPE STEEL
STRENGTH FY 50 FU 62 RY 1.5 RT 1.2
END DEFINE MATERIAL
UNIT FEET KIP
CONSTANTS
MATERIAL STEEL_50_KSI ALL
SUPPORTS
1 PINNED
2 FIXED BUT MZ
LOAD 1
SELFWEIGHT Y -1 
MEMBER LOAD
1 CON GY -22 10
1 CON GY -22 25
PERFORM ANALYSIS
UNIT INCHES KIP
PARAMETER 1
CODE AISC
MAIN 1 ALL
BEAM 1 ALL
FYLD 36 ALL
UNL 180 ALL
TRACK 2 ALL
*CHECK CODE ALL
SELECT OPTIMIZED
FINISH

STAAD Output

                     STAAD.PRO MEMBER SELECTION - (AISC 9TH EDITION)   v1.0
                     ***********************************************
  |--------------------------------------------------------------------------|
  |                                                    Y        PROPERTIES   |
  |*************                                       |        IN INCH UNIT |
  |            *  |=============================|   ===|===     ------------ |
  |MEMBER   1  *  |  AISC SECTIONS              |      |        AX =  20.10  |
  |            *  | ST  W24X68                  |      |   --Z  AY =   8.73  |
  |DESIGN CODE *  |                             |      |        AZ =   7.01  |
  | AISC-1989  *  ===============================   ===|===     SY =  15.70  |
  |            *                                                SZ = 154.43  |
  |            *  |<---LENGTH (FT)=   35.00 --->|               RY =   1.87  |
  |*************                                                RZ =   9.54  |
  |                                                                          |
  |                232.7 (KIP-FEET)                                          |
  |PARAMETER        |               L1  L1  L1                  STRESSES     |
  |IN KIP  INCH     |           L1              L1              IN KIP  INCH |
  |---------------  +                                           -------------|
  | KL/R-Y= 224.42  |                                           FA  =   2.97 |
  | KL/R-Z=  44.02  +       L1                      L1          fa  =   0.00 |
  | UNL   = 180.00  |                                           FCZ =  18.70 |
  | CB    =   1.00  +   L1                              L1      FTZ =  21.60 |
  | CMY   =   0.85  |                                           FCY =  27.00 |
  | CMZ   =   0.85  +                                           FTY =  27.00 |
  | FYLD  =  36.00  |L0                                     L0  fbz =  18.08 |
  | NSF   =   1.00  +---+---+---+---+---+---+---+---+---+---|   fby =   0.00 |
  | DFF   =   0.00 -12.9                                        Fey =   2.97 |
  | dff=      0.00               ABSOLUTE MZ ENVELOPE           Fez =  77.07 |
  | (KL/R)max = 224.42              (WITH LOAD NO.)             FV  =  14.40 |
  |                                                             fv  =   0.00 |
  |                                                                          |
  |                      MAX FORCE/ MOMENT SUMMARY  (KIP-FEET)               |
  |                      -------------------------                           |
  |                                                                          |
  |                AXIAL      SHEAR-Y    SHEAR-Z    MOMENT-Y    MOMENT-Z     |
  |                                                                          |
  |      VALUE       0.0        23.5        0.0         0.0       232.7      |
  |   LOCATION       0.0         0.0        0.0         0.0        17.5      |
  |    LOADING         0           1          0           0           1      |
  |                                                                          |
  |**************************************************************************|
  |*                                                                        *|
  |*                         DESIGN SUMMARY  (KIP-FEET)                     *|
  |*                         --------------                                 *|
  |*                                                                        *|
  |*       RESULT/     CRITICAL COND/     RATIO/         LOADING/           *|
  |         FX              MY             MZ           LOCATION             |
  |        ======================================================            |
  |          PASS        AISC- H1-3       0.967              1               |
  |          0.00 T          0.00      -232.69            17.50              |
  |*                                                                        *|
  |                                                                          |
  |--------------------------------------------------------------------------|
      AISC VERIFICATION PROBLEM FOR BENDING CAPACITY. PAGE 2-1 -- PAGE NO.    4
    48. FINISH
   ****************************************************************************
   **WARNING** SOME MEMBER SIZES HAVE CHANGED SINCE LAST ANALYSIS.
               IN THE POST PROCESSOR, MEMBER QUERIES WILL USE THE LAST
               ANALYSIS FORCES WITH THE UPDATED MEMBER SIZES.
               TO CORRECT THIS INCONSISTENCY, PLEASE DO ONE MORE ANALYSIS.
               FROM THE UPPER MENU, PRESS RESULTS, UPDATE PROPERTIES, THEN
               FILE SAVE; THEN ANALYZE AGAIN WITHOUT THE GROUP OR SELECT