A u t o

®
Autodesk
™
Robot Structural Analysis
Professional
VERIFICATION MANUAL
FOR EC BELGIAN NAD STEEL CODE
March 2014
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
INTRODUCTION ..............................................................................................................................................................................1
STEEL ..............................................................................................................................................................................................2
BELGIUM EUROCODE 3 NBN EN 1993-1:2005/ AC:2009/ ANB:2010 ........................................................................................3
GENERAL REMARKS………………………………………………………………………………………………………………… ……….4
VERIFICATION EXAMPLE - BENDING WITH LATERAL-TORSIONAL BUCKLING ANALYSIS FOR CANTILEVER ……………………… ………..6
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
INTRODUCTION
This verification manual contains numerical examples for structures prepared and originally calculated
by Autodesk Robot Structural Analysis Professional version 2013. The comparison of results is
still valid for the next versions.
All examples have been taken from handbooks that include benchmark tests covering fundamental
types of behaviour encountered in structural analysis. Benchmark results (signed as “Handbook”) are
recalled, and compared with results of Autodesk Robot Structural Analysis Professional (signed further
as “Robot”).
Each example contains the following parts:
- title of the problem
- specification of the problem
- Robot solution to the problem
- outputs with calculation results and calculation notes
- comparison between Robot results and exact solution
- conclusions.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
STEEL
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
Eurocode 3 (Belgian NAD)
NBN EN 1993-1:2005/ AC:2009/
ANB:2010
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
GENERAL REMARKS
Select preferences corresponding to your example using “Preferences…” or “Job Preferences…” (click
Tools).
A.
Preferences
To specify your regional settings in PREFERENCES dialog click Tools/ Preferences.
Default PREFERENCES dialog opens e.g.:
Select appropriate regional setting (e.g. Belgique) from the selection list
B.
Job Preferences
To specify your job preferences in JOB PREFERENCES dialog click Tools/ Job Preferences.
Default JOB PREFERENCES dialog opens, e.g.:
You can define a new type of Job Preferences to make it easier in the future.
First of all, make selection of documents and parameters appropriate for the project conditions from
the list view tabs in JOB PREFERENCES dialog.
For example, to choose code, click Design codes tab from the left list view; then select code from
Steel/Aluminium structures selection list or press More codes button which opens
Configuration of Code List.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
Selection of an appropriate code category (e.g. Steel/Aluminum) from the combo box
opens a new suitable list. Set Belgian code as the current code.
2.
1.
Press OK.
After the job preferences decisions are set,
you can save it under a new name (e.g.
Belgian codes) by pressing
Save Job Preferences icon
in the JOB PREFERENCES dialog.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
VERIFICATION EXAMPLE
Bending with lateral-torsional buckling analysis for
a cantilever I-beam
TITLE:
Critical moment Mcr for lateral torsional buckling of cantilever I-beam according to Belgian standard.
SPECIFICATION:
Calculate the values of critical moment Mcr for two I300 cantilever beams with a span of 3,0 m.
The material is S235. Applied loads: uniform dead loads of pz = -10,0 kN/m acting on the top of
beams. The weight of bars is negligible. The bars are unbraced.
Verify:
1. the first bar
 without warping at the support end (fully fixed)
2. the second one  with warping at the support end
SOLUTION:
After having defined and calculated the structure models, go to [Steel/Aluminum Design] tab.
Define new types of members in accordance with the structure assumptions in DEFINITIONS dialog.
It can be set in Member type combo box list.
In this example, the beams (numbered 1 and 2) have to be defined as a cantilever for the purposes
of a verification.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
For easier start, the pre-defined type of member
(e.g. “beam”) may be initially opened.
On Members tab, for the selected “Beam”
from Member type combo box,
press the Parameters button.
It opens MEMBER DEFINITION - PARAMETERS dialog.
Type a new name in Member type editable field. Next, change the parameters to meet the initial data
requirements of the structure. Set (as needed) the following lateral-buckling parameters:

switch on: the Lateral buckling check box or/and Flexural-torsional buckling check box

define the appropriate Lateral buckling length coefficient for
a member by pressing Upper/Lower flange. It opens
LATERAL BUCKLING LENGTH COEFFICIENTS dialog.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
If a defined “Member type” is indicated as a cantilever the new option is activated in the form
of the check box "Cantilever without warping effects".

select the appropriate Load level icon

define the appropriate load type for a featured member by pressing [More…] button;
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
It opens ADDITIONAL PARAMETERS dialog
next, choose the load type
by pressing the icon - it opens
a new dialog

select Method of calculation

choose Additional sets of member parameters

define bracings for Lateral buckling and Buckling
Can be done in two ways in [MEMBER DEFINITION-MEMBER] dialog:
1st way - by pressing Upper/Lower flange button from Lateral buckling frame
2nd way - by pressing either “Buckling length coeff.” icon from Buckling frame
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
The first method opens
LATERAL BUCKLING LENGTH COEFFICIENTS dialog:
The second one opens
BUCKING TYPE DIAGRAMS dialog:
For both methods if you click the last icon - Intermediate bracings - the new dialog INTERNAL
BRACINGS will appear.
In the INTERNAL BRACINGS
dialog, there are possibilities
to define bracings for buckling
and lateral buckling
for a currently defined member
type independently.
In this particular example no bracings were defined.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
Now, save the newly-created member types under new names.
In the described example two member types were created:
1. “fixed support”  prepared for el.1 without warping at the support end (fully fixed)
2. “warping ends”  prepared for el.2 with warping at member’s ends.
In DEFINITIONS dialog
number of a member must be
assigned to the appropriate name
of Member type.
!!!  It is very important when verifying
different member types.
In DEFINITIONS dialog
also any name of member
can be entered.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
In the CALCULATIONS dialog set the following:
-> Verification options - list of verified members,
-> Loads cases - list of chosen loads
-> Limit state
-> Configuration
Before doing calculations you have to remember to specify appropriate parameters for verification
in the CONFIGURATION dialog. Access the CONFIGURATION dialog by clicking the [Configuration]
button in the CALCULATIONS dialog.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
Now, start the calculations - press the Calculations button in CALCULATIONS dialog.
MEMBER VERIFICATION dialog with the most significant messages (Messages tab) and results data
(Results tab) will appear on screen.
Pressing the line with results for the member 1 opens the RESULTS dialog with detailed results
for the analyzed member. The views of the RESULTS dialogs are presented below.
Simplified results tab
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
Detailed results tab
Pressing the [Calc.Note] button in “RESULTS - Code” dialog opens the printout note for the analyzed
member. You can obtain Simplified results printout or Detailed results printout, depending on from
which tab the choice was made. The printout note view of Simplified results is presented below.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
SIMPLIFIED RESULTS printout for member no1
STEEL DESIGN
---------------------------------------------------------------------------------------------------------------------------------------CODE: NBN EN 1993-1:2005/AC:2009/ANB:2010, Eurocode 3: Design of steel structures.
ANALYSIS TYPE: Member Verification
---------------------------------------------------------------------------------------------------------------------------------------CODE GROUP:
MEMBER: 1 without warping node1
POINT: 1
COORDINATE: x = 0.00 L = 0.00 m
---------------------------------------------------------------------------------------------------------------------------------------LOADS:
Governing Load Case: 1 DL1
---------------------------------------------------------------------------------------------------------------------------------------MATERIAL:
S 235 ( S 235 )
fy = 235.00 MPa
---------------------------------------------------------------------------------------------------------------------------------------SECTION PARAMETERS: IPE 300
h=30.0 cm
gM0=1.00
gM1=1.00
b=15.0 cm
Ay=36.16 cm2
Az=25.68 cm2
Ax=53.81 cm2
tw=0.7 cm
Iy=8356.11 cm4
Iz=603.78 cm4
Ix=19.47 cm4
tf=1.1 cm
Wely=557.07 cm3
Welz=80.50 cm3
---------------------------------------------------------------------------------------------------------------------------------------INTERNAL FORCES AND CAPACITIES:
My,Ed = -45.00 kN*m
My,el,Rd = 130.91 kN*m
My,c,Rd = 130.91 kN*m
Vz,Ed = 30.00 kN
Tau,z,max,Ed = 15.83 MPa
Mb,Rd = 120.19 kN*m
Class of section = 3
---------------------------------------------------------------------------------------------------------------------------------------LATERAL BUCKLING PARAMETERS:
z = 1.00
Mcr = 305.38 kN*m
Curve,LT - b
XLT = 0.89
Lcr,low=6.00 m
Lam_LT = 0.65
fi,LT = 0.70
XLT,mod = 0.92
---------------------------------------------------------------------------------------------------------------------------------------BUCKLING PARAMETERS:
About y axis:
About z axis:
---------------------------------------------------------------------------------------------------------------------------------------VERIFICATION FORMULAS:
Section strength check:
My,Ed/My,c,Rd = 0.34 < 1.00 (6.2.5.(1))
sqrt(Sig,x,Ed*^2 + 3*Tau,z,max,Ed^2)/(fy/gM0) = 0.34 < 1.00 (6.2.1.(5))
Tau,z,max,Ed/(fy/(sqrt(3)*gM0)) = 0.12 < 1.00 (6.2.6.(4))
Global stability check of member:
My,Ed/Mb,Rd = 0.37 < 1.00 (6.3.2.1.(1))
----------------------------------------------------------------------------------------------------------------------------------------
Section OK !!!
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
You can also estimate the verifications for the other section or e.g. lighter IPE section
in a convenient quick way:

while still in RESULTS-CODE dialog, type the required section name only in the combo box
and choose the new section from a list, e.g. HEA 160.
Press ENTER. Calculations and results for entered section are refreshed instantly.
The results printout for the newly selected section can be presented by pressing [Calc.Note] button.
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Autodesk Robot Structural Analysis Professional - Verification Manual for EC NAD for Belgium
COMPARISON of Critical Moment Mcr [kNm]
for lateral-torsional buckling of a cantilever members:
a support of
cantilever
manually
calculated
RSA
according to Belgium NBN EN
CTiCM
LTBeam
IPE 300
fully fixed
305,4
305,9
305,5
fixed with
warping
158,3
158,7
133,3
HEA 160
fully fixed
231,9
233,1
fixed with
warping
151,7
128,2
CONCLUSIONS:
Belgium NBN EN 1993-1:2005/ AC:2009/ ANB:2010 standard provides formulas for calculating Mcr
for a cantilever for two types of its support:
1. without warping at the support end (fully fixed)
2. with warping at the support end (fixed with warping).
Agreement of Mcr results for:

manually calculated & RSA - for all cases calculated according to Belgium standard;

CTiCM LTBeam software & RSA (NBN code) – for a cantilever without warping at the support
end (fully fixed).
The differences between the results of calculations carried out according to Belgium standard and
CTiCM LTBeam software appear for the case of beams with possiblitty of warping at both ends (these
differences resulting from the use of other verification formulas in the above mentioned standards).
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