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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\ASD 9th Edition\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
 ALL UNITS ARE - KIP  INCH (UNLESS OTHERWISE Noted)
 MEMBER     TABLE       RESULT/   CRITICAL COND/     RATIO/     LOADING/
                          FX            MY             MZ       LOCATION
 =======================================================================
  |--------------------------------------------------------------------------|