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V. AS4100 1998 - Cantilever subject to tension and bending

Verify the tension and out-of-plane bending capacities of an I section cantilever beam per the AS 4100 1998 code.

Details

The cantilevered member is 2 m in length. The section is a 250UC89.5 of grade 300 steel. The member is subject to 434 kN in tension.

Section Properties

  • Cross-sectional area, Ag = 11,400 mm2
  • Plastic section modulus, Sxx = 1.23×106 mm3

Material Properties

  • E = 199,947 MPa
  • G = 80,000 MPa
  • Fy,web = 300 MPa
  • Fy,flange = 280 MPa
  • Fu = 440 MPa

Validation

Axial Tension Capacity

Gross yielding:

N ty = A g f y = 11,400 × 280 ( 10 ) -3 = 3,190  kN

Fracture:

Assume net area, An, is equal to the gross area.

Kt = correction factor for distribution of forces = 1.0

N tf = 0.85 K t A n f u = 0.85 × 1.0 × 11,400 × 440 ( 10 ) -3 = 4,264  kN

Nt is the lesser of Nty and Ntf, Nt = 3,190 kN

ϕ N t = 0.9 × 3,190 = 2,870  kN

Section Bending Capacity

M sx = S x f y = 1.23 ( 10 ) 6 280 = 344  kN·m
ϕ M sx = 0.9 × 344 = 310  kN·m

Axial tensile load, N, mitigating flexural-torsional buckling:

M ox = M bx × ( 1 + N ϕ N t ) = 336 ( 1 + 434 2,870 ) = 387  kN·m
ϕ M ox = 0.9 × 387 = 348  kN·m

Results

Result Type Reference STAAD.Pro Difference Comments
Axial tension capacity (kN) 2,870 2,872 negligible  
Member combined out-of-plane bending and tension (kN·m) 310 309.96 negligible  

STAAD.Pro Input

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\09 Steel Design\Australia\AS4100 1998 - Cantilever subject to tension and bending.std is typically installed with the program.

STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 21-Jul-21
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 0 0 0; 2 2 0 0;
MEMBER INCIDENCES
1 1 2;
DEFINE PMEMBER
1 PMEMBER 1
DEFINE MATERIAL START
ISOTROPIC STEEL
E 1.99947e+08
POISSON 0.3
DENSITY 76.8191
ALPHA 6.5e-06
DAMP 0.03
G 7.7221e+07
TYPE STEEL
STRENGTH RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AUSTRALIAN
1 TABLE ST UC250X89.5
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 FIXED
LOAD 1 LOADTYPE None  TITLE LOAD CASE 1
MEMBER LOAD
1 CON X 434 2 0.28
JOINT LOAD
2 FY -88
PERFORM ANALYSIS
PARAMETER 1
CODE AUSTRALIAN
TRACK 2 PMEMB 1
PBRACE TOP 0 F 1 U PMEMB 1
PBRACE BOTTOM 0 F 1 U PMEMB 1
ALM 1 PMEMB 1
CHECK CODE PMEMB ALL
FINISH

STAAD.Pro Output

                    STAAD.Pro CODE CHECKING - (  AS4100-1998   ) V2.3           
                    ****************************************************
   MEMBER DESIGN OUTPUT FOR PMEMBER     1
   DESIGN Notes
   ------------
   1. (*) next to a Load Case number signifies that a P-Delta analysis has not been performed for
      that particular Load Case; i.e. analysis does not include second-order effects.
   2. ϕ = 0.9 for all the calculations [AS4100 Table 3.4]
   3. (#) next to Young's modulus E indicates that its value is not 200000 MPa as per AS4100 1.4.
   DESIGN SUMMARY
   =====================================================================================
   Designation: ST   UC250X89.5               (AUSTRALIAN SECTIONS)
   Governing Load Case:     1*
   Governing Criteria: AS-5.1      
   Governing Ratio:   0.581  (PASS)
   SECTION PROPERTIES
   =====================================================================================
    d:       260.0000 mm   bf:       256.0000 mm
   tf:        17.3000 mm   tw:        10.5000 mm
   Ag:     11400.0000 mm2   J:     1.0400E+06 mm4             Iw:   712.7298E+09 mm6
   Iz:   143.0000E+06 mm4  Sz:     1.2300E+06 mm3 (plastic)   Zz:     1.1000E+06 mm3 (elastic)
   rz:   111.9994E+00 mm
   Iy:    48.4000E+06 mm4  Sy:   575.0000E+03 mm3 (plastic)   Zy:   378.1250E+03 mm3 (elastic)
   ry:    65.1584E+00 mm
   MATERIAL PROPERTIES
   =====================================================================================
   Material Standard        :  AS/NZS 3679.1
   Nominal Grade            :  300
   Residual Stress Category :  HR (Hot-rolled)
   E (#)      :199947.000 MPa    [AS 4100 1.4]
   G          : 80000.000 MPa    [AS 4100 1.4]
   fy, flange :   280.000 MPa    [AS 4100 Table 2.1]
   fy, web    :   320.000 MPa    [AS 4100 Table 2.1]
   fu         :   440.000 MPa    [AS 4100 Table 2.1]
   SLENDERNESS
   =====================================================================================
   Actual slenderness   :  30.694
   Allowable slenderness: 400.000
      STAAD SPACE                                              -- PAGE NO.    4
   BENDING
   =====================================================================================
   Section Bending Capacity
   Critical Load Case:     1*          Critical Ratio:   0.568
   Critical Location:        0.000 m from Start.
   Mz* =   176.0000E+00 KNm                      My* =     0.0000E+00 KNm
   Z-Axis Section Slenderness: Compact           Y-Axis Section Slenderness: Compact
   Zez =     1.2300E+06 mm3                      Zey =   567.1875E+03 mm3
   ϕMsz =   309.9600E+00 KNm                     ϕMsy =   142.9313E+00 KN[AS 4100 5.2.1]
   Member Bending Capacity
   Critical Load Case:     1*          Critical Ratio:   0.581
   Critical Location:        0.000 m from Start.
   Crtiical Segment/Sub-segment: 
   Location (Type):   0.00 m(F )-  2.00 m(U )
   Length:    2.00 m
   Mz* =   176.0000E+00 KNm                      My* =     0.0000E+00 KNm
   kt   =      1.00                         [AS4100 Table 5.6.3(1)]
   kl   =      1.00                         [AS4100 Table 5.6.3(2)]
   kr   =      1.00                         [AS4100 Table 5.6.3(3)]
   le   =      2.00 m                       [AS4100 5.6.3]
   αm   =     1.000                         [AS4100 5.6.1.1(a)(iii)]
   Mo   =     3.2222E+03 KNm                [AS4100 5.6.1.1(a)(iv)]
   αsz  =     0.977                         [AS4100 5.6.1.1(a)(iv)]
   ϕMbz =   302.8551E+00 KNm (<= ϕMsz)      [AS4100 5.6.1.1(a)]
   SHEAR
   =====================================================================================
   Section Shear Capacity
   Critical Load Case:     1*          Critical Ratio:   0.187
   Critical Location:        0.000 m from Start.
   Vy*  =    88.0000E+00 KN
   ϕVvy  =   471.7441E+00 KN                [AS 4100 5.11.2]
   ϕVvmy =   471.7441E+00 KN                [AS 4100 5.12.3]
   Vz*  =     0.0000E+00 KN
   ϕVvz  =     1.3393E+03 KN                [AS 4100 5.11.2]
   ϕVvmz =     1.3393E+03 KN                [AS 4100 5.12.3]
      STAAD SPACE                                              -- PAGE NO.    5
   AXIAL
   =====================================================================================
   Section Compression Capacity
   Critical Load Case:     1*          Critical Ratio:   0.000
   Critical Location:        0.000 m from Start.
   N*    =     0.0000E+00 KN
   Ae    =    11.4000E+03 mm2               [AS 4100 6.2.3 / 6.2.4]
   kf    =     1.000                        [AS 4100 6.2.2]
   An    =    11.4000E+03 mm2
   ϕNs   =     2.8728E+03 KN                [AS 4100 6.2.1]
   Member Compression Capacity
   Lz    =      2.00 m
   Ly    =      2.00 m
   Lez   =      2.00 m
   Ley   =      2.00 m
   αb    =      0.00                        [AS 4100 Table 6.3.3(1)/6.3.3(2)]
   λn,z  =    18.898                        [AS 4100 6.3.3]
   αa,z  =     5.352                        [AS 4100 6.3.3]
   λ,z   =    18.898                        [AS 4100 6.3.3]
    h ,z   =     0.018                        [AS 4100 6.3.3]
    x ,z   =    12.039                        [AS 4100 6.3.3]
   αc,z  =     0.982                        [AS 4100 6.3.3]
   ϕNcz  = 0.2821E+4 KN                     [AS 4100 6.3.3]
   λn,y  =    32.484                        [AS 4100 6.3.3]
   αa,y  =    15.285                        [AS 4100 6.3.3]
   λ,y   =    32.484                        [AS 4100 6.3.3]
    h ,y   =     0.062                        [AS 4100 6.3.3]
    x ,y   =     4.576                        [AS 4100 6.3.3]
   αc,y  =     0.934                        [AS 4100 6.3.3]
   ϕNcy  = 0.2684E+4 KN                     [AS 4100 6.3.3]
   ϕNc   = N/A                              [AS 4100 6.3.3 / AS 4600 3.4.1(b)]
   Section Tension Capacity
   Critical Load Case:     1*          Critical Ratio:   0.151
   Critical Location:        0.000 m from Start.
   N*    =  -434.0000E+00 KN
   kt    =      1.00                        [User defined]
   An    =    11.4000E+03 mm2
   ϕNt   =     2.8728E+03 KN                [AS 4100 7.2]
      STAAD SPACE                                              -- PAGE NO.    6
   COMBINED BENDING AND AXIAL
   =====================================================================================
   Section Combined Capacity
   Critical Condition: Cl 8.3.2
   Critical Load Case:     1*          Critical Ratio:   0.568
   Critical Location:        0.000 m from Start.
   N* =  -434.0000E+00 KN    Mz* =   176.0000E+00 KNm      My* =     0.0000E+00 KNm
   ϕNs   =     2.8728E+03 KN                [AS 4100 8.3.1]
   ϕMsz  =   309.9600E+00 KNm
   ϕMsy  =   142.9313E+00 KNm
   ϕMrz  =   309.9600E+00 KNm               [AS 4100 8.3.2]
   ϕMry  =   142.9313E+00 KNm               [AS 4100 8.3.3]
   Member Combined Capacity - In-plane
   Critical Load Case: N/A             Critical Ratio: N/A
   Critical Location: N/A
   Member Combined Capacity - Out-of-plane(compression)
   Critical Load Case: N/A             Critical Ratio: N/A
   Critical Location: N/A
   Member Combined Capacity - Out-of-plane(tension)
   Critical Load Case:     1*          Critical Ratio:   0.568
   Critical Location:        0.000 m from Start.
   N* =  -434.0000E+00 KN    Mz* =   176.0000E+00 KNm      My* =     0.0000E+00 KNm
   ϕMbz  =   302.8551E+00 KNm
   ϕNt   =     2.8728E+03 KN                [AS 4100 8.4.4.2]
   ϕMozt =   309.9600E+00 KNm               [AS 4100 8.4.4.2]
   Member Combined Capacity - Biaxial(compression)
   Critical Load Case: N/A             Critical Ratio: N/A
   Critical Location: N/A
   Member Combined Capacity - Biaxial(tension)
   Critical Load Case:     1*          Critical Ratio:   0.453
   Critical Location:        0.000 m from Start.
   N* =  -434.0000E+00 KN    Mz* =   176.0000E+00 KNm      My* =     0.0000E+00 KNm
   ϕMtz  =   309.9600E+00 KNm               [AS 4100 8.4.5.2]
   ϕMry  =   142.9313E+00 KNm               [AS 4100 8.4.5.2]
      STAAD SPACE                                              -- PAGE NO.    7
   ********************************************************************************