V. AISC N690 1994 Pipe
Verify the design of a pipe section used for a beam member per the AISC N690 1994 code.
Details
The simply supported beam is 50 inches long. The beam is loaded with a 1.5 kip concentrated load at midspan and a uniformly distributed load of 1 kip/in over the entire length.
The member is PIPS 120 pipe section with Grade A36 steel.
Validation
Maximum shear force,
Maximum moment,
Slenderness ratio = (KL/r) = 9.72 < 300
Bending About Major Axis (Z-Axis)
Section is compact:
Allowable bending stress: Fb = 0.66×Fy = 23.76 ksi
Actual bending stress:
Stress ratio: 0.339
Shear
From the reference, the shear area:
Shear area: Ay = 6.8 in2
Actual shear stress (at supports): fv = 25.75 / 6.8 = 3.78 ksi
Actual shear stress (at midspan): fv = 0.75 / 6.8 = 0.110 ksi
Allowable shear stress, Fv = 0.4×Fy = 14.4 ksi
Stress ratio: 3.78/14.4 = 0.263
Results
Parameter | Hand Calculation | STAAD.Pro | Difference | Comments |
---|---|---|---|---|
Slenderness ratio | 9.72 | 9.72 | none | |
Allowable bending stress (ksi) | 23.76 | 23.76 | none | |
Actual bending stress (ksi) | 8.06 | 8.06 | none | |
Critical stress ratio | 0.339 | 0.339 | none | |
Allowable shear stress (ksi) | 14.4 | 14.4 | none |
STAAD Input
The file C:\Users\Public\Public Documents\STAAD.Pro 2024\Samples \Verification Models\09 Steel Design\US\AISC\AISC N690 1994 Pipe.std is typically installed with the program.
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 17-Aug-18
END JOB INFORMATION
INPUT WIDTH 79
SET SHEAR
UNIT INCHES POUND
JOINT COORDINATES
1 0 0 0; 2 50 0 0;
MEMBER INCIDENCES
1 1 2;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.9e+07
POISSON 0.3
DENSITY 0.283
ALPHA 1.2e-05
DAMP 0.03
TYPE STEEL
STRENGTH FY 36000 FU 58000 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
1 TABLE ST PIPS120
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 PINNED
2 FIXED BUT FX MY MZ
LOAD 1 LOADTYPE None TITLE LOAD CASE 1
MEMBER LOAD
1 CON GY -1500 25 0
1 UNI GY -1000 0 50
PERFORM ANALYSIS
PARAMETER 1
CODE AISC N690
CMY 1 ALL
CMZ 1 ALL
CT 0.85 ALL
FU 58000 ALL
FYLD 36000 ALL
KY 0.85 ALL
KZ 0.85 ALL
UNT 50 ALL
UNB 50 ALL
MAIN 200 ALL
NSF 0.9 ALL
RATIO 1 ALL
TMAIN 300 ALL
UNB 25 ALL
UNT 25 ALL
STYPE 1 ALL
TRACK 2 ALL
CHECK CODE ALL
FINISH
STAAD Output
STAAD.PRO CODE CHECKING - ( ANSI N690-1994) v1.0
********************************************
|--------------------------------------------------------------------------|
| Y PROPERTIES |
|************* | IN INCH UNIT |
| * |=============================| ==| |== ------------ |
|MEMBER 1 * | AISC SECTIONS | | | AX = 13.70 |
| * | ST PIPS120 | | | --Z AY = 6.80 |
|DESIGN CODE * | | | | AZ = 6.80 |
|ANSI N690-94* =============================== ==| |== SY = 41.10 |
| * SZ = 41.10 |
| * |<---LENGTH (FT)= 4.17 --->| RY = 4.37 |
|************* RZ = 4.37 |
| |
| 27.6 (KIP-FEET) |
|PARAMETER | L1 L1 L1 STRESSES |
|IN KIP INCH | IN KIP INCH |
|--------------- + L1 L1 -------------|
| KL/R-Y= 9.72 | FA = 15.87 |
| KL/R-Z= 9.72 + L1 L1 fa = 0.00 |
| UNL = 25.00 | FCZ = 23.76 |
| CB = 1.00 + L1 L1 FTZ = 23.76 |
| CMY = 1.00 | FCY = 23.76 |
| CMZ = 1.00 + FTY = 23.76 |
| FYLD = 36.00 |L0 L0 fbz = 8.06 |
| NSF = 0.90 +---+---+---+---+---+---+---+---+---+---| fby = 0.00 |
| DFF = 0.00 -1.5 Fey =1409.49 |
| dff= 0.00 ABSOLUTE MZ ENVELOPE Fez =1409.49 |
| (KL/R)max = 9.72 (WITH LOAD NO.) FV = 14.40 |
| fv = 0.11 |
| |
| MAX FORCE/ MOMENT SUMMARY (KIP-FEET) |
| ------------------------- |
| |
| AXIAL SHEAR-Y SHEAR-Z MOMENT-Y MOMENT-Z |
| |
| VALUE 0.0 25.8 0.0 0.0 27.6 |
| LOCATION 0.0 0.0 0.0 0.0 2.1 |
| LOADING 0 1 0 0 1 |
| |
|**************************************************************************|
|* *|
|* DESIGN SUMMARY (KIP-FEET) *|
|* -------------- *|
|* *|
|* RESULT/ CRITICAL COND/ RATIO/ LOADING/ *|
| FX MY MZ LOCATION |
| ====================================================== |
| PASS ANSI Q1.6-2 0.339 1 |
| 0.00 T 0.00 -27.60 2.08 |
|* *|
| |