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Computer Applications for Civil Engineers

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Investigation Aims ... Note, real stress many time less due to rubber mountings ... Basic design performed adequately under prescribed loading conditions ... – PowerPoint PPT presentation

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Title: Computer Applications for Civil Engineers


1
Computer Applications for Civil Engineers
  • FINITE ELEMENT ANALYSIS INVESTIGATION

ADELAIDE CONVENTION CENTRE
Anthony Avolio Daniel Shaw
2
Investigation Aims
  • To model the Adelaide Convention Centres recent
    extension in order to analyse its behaviour under
    various expected loading conditions.
  • To investigate limitations that the glass
    superstructure imposes on the building design.

3
Project Description
  • Structure from Galvanised Structural Steel
  • Glass Façade from 18mm toughened Glass
  • All connections are welded
  • Some aspects have been simplified for modelling
    purposes

4
Project Scope Overview
5
Material Sections
  • 1. Main Columns 600 x 20mm CHS
  • 2. Secondary Columns 250 x 250 x 10mm SHS
  • 3. Horizontal Glass Frame Beam 250 x 100 x 15 mm
    TS

6
Material Sections
  • 4. Column to Frame Link
  • 250 x 800 x 20 mm HRS
  • 5. Vertical Frame Brace
  • 35 x 35 x 2 mm SHS
  • 6. Secondary Vertical Frame Brace
  • 50 x 50 x 5mm SHS

7
Materials
  • All Structural members in this analysis were
    taken as standard Structural Steel (500Mpa)
  • The Glass Façade was taken to be 18mm thick
    toughened glass.

8
Model Design Assumptions
  • Restraint Conditions
  • - Fully Fixed at Bottom
  • - Partially restrained at top of main columns
  • Model Simplified
  • - Removal of Vertical Rods
  • - Roof Not Modeled Assumed Restraints

9
Model Design Assumptions
10
Model Design Assumptions
11
Loading and Analysis Conditions
  • Three Loading Conditions were investigated
  • 1. Self Weight (end of construction)
  • 2. Northerly Wind (1000yr design)
  • 3. Partial Structure destruction Wind
  • Wind loading was taken to be a function of Site
    Wind Speed and shielding Factors.
  • Site Wind Speed 49m/s
  • Site Wind Pressure 1380pa

12
Self Weight Analysis
  • Gravitational acceleration taken as 9.81m/s/s in
    the Z
  • No wind or external factors are taken into
    account here
  • Displacement and Stress of the beams and plates
    were investigated

13
Self Weight Beam Deflection (X)
  • Maximum Displacement
  • 16.3mm (-ve X)
  • 2.9mm (ve X)

14
Self Weight Beam Deflection (Y)
  • Maximum Displacement
  • 13.3mm (ve Y)
  • 8.1mm (-ve Y)

15
Self Weight Beam Deflection (Z)
  • Maximum Displacement
  • 2.0mm (ve Z)
  • 0.6mm (-ve Z)

16
Self Weight Plate Deflection (X)
  • Maximum Displacement
  • 16.3mm (-ve X)
  • 2.9mm (ve X)

17
Self Weight Plate Deflection (Y)
  • Maximum Displacement
  • 13.3mm (ve Y)
  • 8.1mm (-ve Y)

18
Self Weight Plate Deflection (Z)
  • Maximum Displacement
  • 2.0mm (ve Z)
  • 0.6mm (-ve Z)

19
North Wind Analysis
  • Gravitational acceleration taken as 9.81m/s/s in
    the Z
  • Critical Wind Taken From North No Shielding
  • Additional Roof Uplift modeled

20
North Wind Analysis Beam Deflection
  • Maximum Displacement
  • X ? -25.3mm
  • Y ? 13.3mm
  • Z ? 2.1mm
  • Critical In X Direction

21
North Wind Analysis Plate Deflection
  • Maximum Displacement
  • X ? -27.4mm
  • Y ? 13.2mm
  • Z ? 2.0mm
  • Critical In X Direction
  • (similar deflection to Beams)

22
North Wind Analysis Critical Plate Deflection
  • Critical Plate Displacement 27.4mm ve X
    direction.
  • Direct wind loading and Height of Wall as the
    main contributing factors

23
North Wind Analysis Deflection
  • Critical Total Displacement of approximately 25mm
  • Note, Plate and Beam Similarities

24
North Wind Analysis Beam Deflection
25
North Wind Analysis Plate Deflection
26
North Wind Analysis Stress (xz plane)
  • Critical Plate Stress of 171kpa
  • Note, real stress many time less due to rubber
    mountings difficult to model.

27
North Wind Analysis Stress (yz plane)
  • Critical Plate Stress of 230kpa
  • Theoretical Glass strength in excess of 1x106
    PSI
  • Aprox. 6900Mpa

28
North Wind Analysis Stress in Beams
Bending Stress in Beam diagram appears to show
all members with little to no bending
stress. Maximum Bending Stress - x (plane 1)
478Mpa - y (plane 2) 390Mpa Large Bending
Stresses occur in localised areas
X
Y
29
North Wind Analysis Stress in Beams Zoom (plane
1, x)
Maximum Bending Stress - x (plane 1)
478Mpa Localised Area in connection member
between main column and glass support
structure. Incorrect orientation of member
resulted in localised loading of the connection
member.
30
North Wind Analysis Stress in Beams Zoom (plane
2, y)
Maximum Bending Stress - y (plane 2)
390Mpa Localised Area within top of main support
column. Severe uplift load at this point
combined with axial loading from North Wind
resulted in high bending stress Both Planes (x,
y) satisfactory lt 500Mpa
31
North Wind Analysis Axial Stress
Maximum Axial Stress 616Mpa. Exceeds limit of
500Mpa.
32
North Wind Analysis Axial Stress (ve)
Max 616Mpa Un-realistic and excessive Axial
stress caused by inadequate modelling of
restraint conditions, and use of simplified
concrete wall structure.
33
North Wind Analysis Axial Stress (-ve)
Max -178Mpa Realistic modelling as this area
is transferring load from front facia
(perpendicular to wind loading) to a wall
parallel to wind load direction, causing
compression of members.
34
Partial Destruction Analysis
This model investigates a situation where by a
serious structural breach has occurred. Three
main support columns on the northern face have
been removed and plate glass has also been
removed. Loading includes a 10kN/m loading on
the north facing beams simulating a pressure wave.
35
Partial Destruction Analysis
Maximum Beam Displacement 14.4m Maximum Plate
Displacement 9.05m Although displacements are
sever, structural integrity is relatively
maintained. Roof Loads are not taken into
consideration here (i.e. roof removal by pressure
wave)
36
Issues with design and analysis
  • Inability to accurately model roof loadings and
    restraints
  • Simplification of glass frame necessary for
    modelling
  • Restraint conditions partially assumed
  • Glass Material and connection method extremely
    difficult to model within Strand 7
  • Temperature effects were modelled with little to
    no effect to overall performance of structure

37
Conclusion
  • Basic design performed adequately under
    prescribed loading conditions
  • Issues with severity of bending and axial stress
    within beam members to be further analysed
    suspected issue with member orientation and
    restraints
  • Strand7 as a powerful modelling tool allowed a
    comprehensive analysis of the Convention Centre
    extension facade
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