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Active Contributor
Burgon87
Posts: 46
Registered: ‎03-21-2012

STEEL DESIGN - EC3 - Failing Members

404 Views, 4 Replies
05-03-2012 03:12 AM

Please can someone help?

 

I have two members that are loaded similarly and one fails and the other does not, can someone tell me within the results attached why one is failing?

 

Many Thanks.

 

STEEL DESIGN

----------------------------------------------------------------------------------------------------------------------------------------

CODE:

   BS-EN 1993-1:2005/NA:2008/AC:2009,  Eurocode 3: Design of steel structures.

ANALYSIS TYPE:

   Member Verification

----------------------------------------------------------------------------------------------------------------------------------------

CODE GROUP:

     

MEMBER:

   63  Beam_63POINT:   1COORDINATE:   x = 0.75 L = 5.715 m

----------------------------------------------------------------------------------------------------------------------------------------

LOADS:

Governing Load Case:

   17 1.2DL + 1.2LL + 1.2WL(S)  (1+2+3+4+5+14)*1

----------------------------------------------------------------------------------------------------------------------------------------

MATERIAL:

S355  ( S355 )       fy = 355 MPa         

 

----------------------------------------------------------------------------------------------------------------------------------------

   SECTION PARAMETERS:  CHS 114.3x5

h=114.300 mm gM0=1 gM1=1

b=114.300 mm Ay=1094.986 mm2 Az=1094.986 mm2 Ax=1720.000 mm2

tw=5.000 mm Iy=2570000.000 mm4 Iz=2570000.000 mm4 Ix=5140000.000 mm4

tf=5.000 mm Wply=59774.117 mm3 Wplz=59774.117 mm3

----------------------------------------------------------------------------------------------------------------------------------------

INTERNAL FORCES AND CAPACITIES:

N,Ed = -334.30 kN  My,Ed = 12 kN*m Mz,Ed = -2 kN*m Vy,Ed = -1.31 kN

Nt,Rd = 610.60 kN My,pl,Rd = 21 kN*m Mz,pl,Rd = 21 kN*m Vy,T,Rd = 136.02 kN

My,c,Rd = 21 kN*m Mz,c,Rd = 21 kN*m Vz,Ed = -5.76 kN

My,N,Rd = 14 kN*m Mz,N,Rd = 14 kN*m Vz,T,Rd = 136.02 kN

Tt,Ed = 7 kN*m

Class of section = 1

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     LATERAL BUCKLING PARAMETERS:

----------------------------------------------------------------------------------------------------------------------------------------

BUCKLING PARAMETERS:

      About Y axis:       About Z axis:

----------------------------------------------------------------------------------------------------------------------------------------

VERIFICATION FORMULAS:

 

Section strength check:

N,Ed/Nt,Rd = 1 < 1   (6.2.3.(1))

(My,Ed/My,N,Rd)^ 2 + (Mz,Ed/Mz,N,Rd)^2 = 1 < 1   (6.2.9.1.(6))

Vy,Ed/Vy,T,Rd = 0 < 1   (6.2.6-7)

Vz,Ed/Vz,T,Rd = 0 < 1   (6.2.6-7)

Tau,ty,Ed/(fy/(sqrt(3)*gM0)) = 0 < 1   (6.2.6)

Tau,tz,Ed/(fy/(sqrt(3)*gM0)) = 0 < 1   (6.2.6)

----------------------------------------------------------------------------------------------------------------------------------------

Section OK !!!

STEEL DESIGN

----------------------------------------------------------------------------------------------------------------------------------------

CODE:

   BS-EN 1993-1:2005/NA:2008/AC:2009,  Eurocode 3: Design of steel structures.

ANALYSIS TYPE:

   Member Verification

----------------------------------------------------------------------------------------------------------------------------------------

CODE GROUP:

     

MEMBER:

   64  Beam_64POINT:   1COORDINATE:   x = 0.75 L = 5.715 m

----------------------------------------------------------------------------------------------------------------------------------------

LOADS:

Governing Load Case:

   17 1.2DL + 1.2LL + 1.2WL(S)  (1+2+3+4+5+14)*1

----------------------------------------------------------------------------------------------------------------------------------------

MATERIAL:

S355  ( S355 )       fy = 355 MPa         

 

----------------------------------------------------------------------------------------------------------------------------------------

   SECTION PARAMETERS:  CHS 114.3x5

h=114.300 mm gM0=1 gM1=1

b=114.300 mm Ay=1094.986 mm2 Az=1094.986 mm2 Ax=1720.000 mm2

tw=5.000 mm Iy=2570000.000 mm4 Iz=2570000.000 mm4 Ix=5140000.000 mm4

tf=5.000 mm Wply=59774.117 mm3 Wplz=59774.117 mm3

----------------------------------------------------------------------------------------------------------------------------------------

INTERNAL FORCES AND CAPACITIES:

N,Ed = 308.06 kN  My,Ed = 17 kN*m Mz,Ed = -0 kN*m Vy,Ed = -0.25 kN

Nc,Rd = 610.60 kN My,pl,Rd = 21 kN*m Mz,pl,Rd = 21 kN*m Vy,T,Rd = 120.07 kN

Nb,Rd = 610.60 kN My,c,Rd = 21 kN*m Mz,c,Rd = 21 kN*m Vz,Ed = -8.49 kN

My,N,Rd = 15 kN*m Mz,N,Rd = 15 kN*m Vz,T,Rd = 120.07 kN

Tt,Ed = 9 kN*m

Class of section = 1

----------------------------------------------------------------------------------------------------------------------------------------

     LATERAL BUCKLING PARAMETERS:

----------------------------------------------------------------------------------------------------------------------------------------

BUCKLING PARAMETERS:

      About Y axis:       About Z axis:

----------------------------------------------------------------------------------------------------------------------------------------

VERIFICATION FORMULAS:

 

Section strength check:

N,Ed/Nc,Rd = 1 < 1   (6.2.4.(1))

(My,Ed/My,N,Rd)^ 2 + (Mz,Ed/Mz,N,Rd)^2 = 1 > 1   (6.2.9.1.(6))

Vy,Ed/Vy,T,Rd = 0 < 1   (6.2.6-7)

Vz,Ed/Vz,T,Rd = 0 < 1   (6.2.6-7)

Tau,ty,Ed/(fy/(sqrt(3)*gM0)) = 0 < 1   (6.2.6)

Tau,tz,Ed/(fy/(sqrt(3)*gM0)) = 0 < 1   (6.2.6)

----------------------------------------------------------------------------------------------------------------------------------------

Incorrect section !!!

 

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Valued Mentor
tony.ridley
Posts: 652
Registered: ‎09-07-2011

Re: Failing Members

05-03-2012 03:25 AM in reply to: Burgon87

one is in tension, one is in compression?

 

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Product Support
Artur.Kosakowski
Posts: 5,065
Registered: ‎12-17-2010

Re: Failing Members

05-07-2012 12:50 AM in reply to: Burgon87

N,Ed/Nt,Rd = 1 < 1   (6.2.3.(1))

(My,Ed/My,N,Rd)^ 2 + (Mz,Ed/Mz,N,Rd)^2 = 1 < 1   (6.2.9.1.(6))

 

N,Ed/Nc,Rd = 1 < 1   (6.2.4.(1))

(My,Ed/My,N,Rd)^ 2 + (Mz,Ed/Mz,N,Rd)^2 = 1 > 1   (6.2.9.1.(6))

 

Please increase the precision of displaying the results. From the info you provided I assume it is sort of 0.999 < 1 for one of the bars and 1.001> 1 for the other.

 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.



Artur Kosakowski
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Valued Contributor
jo2ny
Posts: 82
Registered: ‎02-07-2012

Re: Failing Members

11-05-2012 03:22 AM in reply to: Artur.Kosakowski

I have a question regarding a verification note.

 

Is it possible to have this: Tau,ty,Ed/(fy/(sqrt(3)*gM0)) = 1.41 > 1.00 (6.2.6)

All the efforts in the bar are very small.

 

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Product Support
Artur.Kosakowski
Posts: 5,065
Registered: ‎12-17-2010

Re: Failing Members

11-05-2012 03:33 AM in reply to: jo2ny

Torsion.



Artur Kosakowski
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