Computer Applications for Civil Engineers

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Computer Applications for Civil Engineers

• FINITE ELEMENT ANALYSIS INVESTIGATION

ADELAIDE CONVENTION CENTRE
Anthony Avolio Daniel Shaw
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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.

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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

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Project Scope Overview
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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

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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

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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.

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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

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Model Design Assumptions
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Model Design Assumptions
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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

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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

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Self Weight Beam Deflection (X)

• Maximum Displacement
• 16.3mm (-ve X)
• 2.9mm (ve X)

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Self Weight Beam Deflection (Y)

• Maximum Displacement
• 13.3mm (ve Y)
• 8.1mm (-ve Y)

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Self Weight Beam Deflection (Z)

• Maximum Displacement
• 2.0mm (ve Z)
• 0.6mm (-ve Z)

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Self Weight Plate Deflection (X)

• Maximum Displacement
• 16.3mm (-ve X)
• 2.9mm (ve X)

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Self Weight Plate Deflection (Y)

• Maximum Displacement
• 13.3mm (ve Y)
• 8.1mm (-ve Y)

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Self Weight Plate Deflection (Z)

• Maximum Displacement
• 2.0mm (ve Z)
• 0.6mm (-ve Z)

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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

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North Wind Analysis Beam Deflection

• Maximum Displacement
• X ? -25.3mm
• Y ? 13.3mm
• Z ? 2.1mm
• Critical In X Direction

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North Wind Analysis Plate Deflection

• Maximum Displacement
• X ? -27.4mm
• Y ? 13.2mm
• Z ? 2.0mm
• Critical In X Direction
• (similar deflection to Beams)

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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

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North Wind Analysis Deflection

• Critical Total Displacement of approximately 25mm
• Note, Plate and Beam Similarities

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North Wind Analysis Beam Deflection
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North Wind Analysis Plate Deflection
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North Wind Analysis Stress (xz plane)

• Critical Plate Stress of 171kpa
• Note, real stress many time less due to rubber
  mountings difficult to model.

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North Wind Analysis Stress (yz plane)

• Critical Plate Stress of 230kpa
• Theoretical Glass strength in excess of 1x106
  PSI
• Aprox. 6900Mpa

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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
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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.
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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
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North Wind Analysis Axial Stress
Maximum Axial Stress 616Mpa. Exceeds limit of
500Mpa.
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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.
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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.
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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.
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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)
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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

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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