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V. AISC LRFD - Round HSS Compression Capacity

To validate that an American Round HSS 10.000X0.5 compression member has a design compressive strength of about 364 kips.

Reference

Hand calculation using the following reference:

AISC Load Factor Resistance Design, 3rd Edition, Table 4-7, Page 4-68.

Problem

Fy = 42 ksi

Length = 20 ft

Comparison

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

Table 1. Comparison of results
Result Type Theory STAAD.Pro Difference
Design strength (kips) 364 364.22 none

STAAD Input

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\09 Steel Design\US\AISC\LRFD 3rd Edition\AISC LRFD - Round HSS Compression Capacity.STD is typically installed with the program.

STAAD SPACE AXIAL COMPRESSION CAPACITY PER AISC LRFD 3RD ED
START JOB INFORMATION
ENGINEER DATE 23-Sep-18
END JOB INFORMATION
*
*  DESIGN COMPRESSIVE STRENGTH OF A ROUND HSS 10.000X0.5
*  TABLE 4-7, PAGE 4-68, AISC LRFD 3RD ED.
*  CAPACITY (PNC) SHOULD BE ABOUT 364 KIPS
*
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 0 20 0;
MEMBER INCIDENCES
1 1 2;
MEMBER PROPERTY AMERICAN
1 TABLE ST HSSP10X0.5
UNIT INCHES KIP
DEFINE MATERIAL START
ISOTROPIC MATERIAL1
E 29000
POISSON 0.3
END DEFINE MATERIAL
UNIT FEET KIP
CONSTANTS
MATERIAL MATERIAL1 ALL
SUPPORTS
1 PINNED
2 FIXED BUT FY MX MZ
LOAD 1
JOINT LOAD
2 FY -350
PERFORM ANALYSIS
UNIT INCHES KIP
PARAMETER 1
CODE LRFD
FYLD 42 ALL
TRACK 1 ALL
CHECK CODE ALL
FINISH

STAAD Output

                         STAAD.Pro CODE CHECKING - (LRFD 3RD EDITION)   v1.0
                         ***********************
 ALL UNITS ARE - KIP  INCH (UNLESS OTHERWISE Noted)
 MEMBER     TABLE       RESULT/   CRITICAL COND/     RATIO/     LOADING/
                          FX            MY             MZ       LOCATION
 =======================================================================
      1  ST   HSSP10X0.5               (AISC SECTIONS)
                           PASS     HSS COMPRESS       0.961         1
                      350.00 C          0.00           0.00        0.00
 +---------------------------------------------------------------------+
 | DESIGN STRENGTHS FOR MEMBER     1                    UNITS - KIP IN |
 | PNC=  364.22      PNT=  525.42      MNZ= 1598.94       MNY= 1598.94 |
 | VNZ=  157.63      VNY=  157.63      TN= 1440.18                     |
 +---------------------------------------------------------------------+