# V. AISC LRFD - Non Compact Wide Flange 2

To determine the design bending strength of a non-compact American wide flange section bent about its strong axis. The deflection at mid-span due to 2 concentrated loads acting at the third points along the beam is also to be calculated.

## Reference

AISC Load Factor Resistance Design, 3rd Edition, Example 5.2, case (a), page 5-16.

## Problem

W21x48 shape

 Fy = 50 ksi

 Length = 40 ft

 Lb = 5 ft

## Comparison

The reported STAAD.Pro value is based on the term MNZ in the STAAD.Pro output.

Table 1. Comparison of results
Deflection (in) 1.41 1.41 none
Design bending strength, ϕbMn 398

398.4

(4,780.24 in·kips)

none
Note: Fully braced condition can be achieved by setting the UNT parameter equal to 1.0 inch.

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\09 Steel Design\US\AISC\LRFD 3rd Edition\AISC LRFD - Non Compact Wide Flange 2.STD is typically installed with the program.

``````STAAD SPACE BENDING CAPACITY PER AISC LRFD 3RD ED
START JOB INFORMATION
ENGINEER DATE 23-Sep-18
END JOB INFORMATION
*
*  EXAMPLE PROBLEM 5.2, CASE (A), PAGE 5-16, AISC LRFD 3RD ED.
*  CAPACITY (MNZ) SHOULD BE ABOUT 398 KIP-FT
*
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 40 0 0;
*
MEMBER INCIDENCES
1 1 2;
*
MEMBER PROPERTY AMERICAN
1 TABLE ST W21X48
*
DEFINE MATERIAL START
ISOTROPIC MATERIAL1
E 4.176e+06
POISSON 0.3
END DEFINE MATERIAL
CONSTANTS
MATERIAL MATERIAL1 ALL
*
SUPPORTS
1 PINNED
2 FIXED BUT MZ
*
1 CON GY -10 13.333
1 CON GY -10 26.667
*
PERFORM ANALYSIS
*
SECTION 0.5 ALL
PRINT SECTION DISPL
*
PARAMETER 1
CODE LRFD
MAIN 1 ALL
FYLD 7200 ALL
UNT 5 ALL
TRACK 1 ALL
CHECK CODE ALL
FINISH
``````

```     MEMBER SECTION DISPLACEMENTS
----------------------------
UNITS ARE - INCH
MEMB  LOAD     GLOBAL X,Y,Z DISPL FROM START TO END JOINTS AT 1/12TH PTS
1     1       0.0000    0.0000    0.0000    0.0000   -0.3644    0.0000
0.0000   -0.7057    0.0000    0.0000   -1.0010    0.0000
0.0000   -1.2273    0.0000    0.0000   -1.3654    0.0000
0.0000   -1.4114    0.0000    0.0000   -1.3654    0.0000
0.0000   -1.2273    0.0000    0.0000   -1.0010    0.0000
0.0000   -0.7057    0.0000    0.0000   -0.3644    0.0000
0.0000    0.0000    0.0000
MAX LOCAL  DISP =    1.41141   AT     240.00  LOAD    1   L/DISP=    340
************ END OF SECT DISPL RESULTS ***********
40. *
41. PARAMETER 1
42. CODE LRFD
43. MAIN 1 ALL
44. FYLD 7200 ALL
45. UNT 5 ALL
46. TRACK 1 ALL
47. CHECK CODE ALL
STEEL DESIGN
BENDING CAPACITY PER AISC LRFD 3RD ED                    -- PAGE NO.    4
STAAD.Pro CODE CHECKING - (LRFD 3RD EDITION)   v1.0
***********************
ALL UNITS ARE - KIP  FEET (UNLESS OTHERWISE Noted)