AKASHIKAIKYO ANALYSIS

1
AKASHI-KAIKYO ANALYSIS
Deck 36m x 14m
Tower 40m x 10m
2
AKASHI-KAIKYO DATA

• Six traffic lanes
• Hanger spacing 10m
• Main cables
• 5.23mm diameter wires
• 127 wires per strand
• 290 strands
• ? Dmain 1.00m (actual diameter 1.12m)

3
DECK TRUSS

• Reduce wind load 75 due to openings
• Load (3.88KPa)(.75)(14m) 40.7KN/m
• Bending moment for two-hinge system
• Wind stress with safety factor of 1.5
• ?Adeck 0.509m2

4
DECK GRAVITY LOADS

• Dead deck load
• Deck truss
• Six lanes of live load

5
DECK GRAVITY STRESS

• Uniform load
• Bending moment
• Safety factor

6
HANGER CABLES

• Gravity stress with safety factor of 2
• ? Ahanger 0.00547m2

7
UNIFORM GRAVITY LOAD

• Equivalent uniform load hanger cables
• Equivalent uniform load main cables
• Total uniform load
• (4723126)KN/m 601KN/m

8
MAIN CABLE CENTER SPAN

• safety factor

9
MAIN CABLE END SPAN
10
TOWER

• Wind moment on tower
• Stress with safety factor of 1.5
• ? Atower 1.46m2

11
TOWER BUCKLING

• Axial force at base of tower
• In-plane buckling safety factor
• Out-of-plane buckling safety factor

12
SUPPORT REACTIONS

• At each of four anchorages
• Horizontal tension 1277MN/2 639MN
• Vertical downward 21.5MN/2 11MN
• At each of two piers
• Vertical upward 1330MN
• Wind moment 5629MNm

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SAFETY FACTOR SUMMARY

• Deck stress wind 1.5
• Deck stress gravity 998
• Hanger cable gravity stress 2
• Main cable gravity stress 1.98
• Tower wind and gravity stress 1.5
• Tower in-plane buckling 2.44
• Tower out-of-plane buckling 9.75

14
CABLE-STAYED AKASHI-KAIKYO

• Suppose the main and hanger cables of the
  Akashi-Kaikyo Bridge were replaced with stay
  cables -- one plane of cables on each side of the
  bridge, horizontally spaced at 10m, and
  vertically spaced at 2m.
• Design stay cables with safety factor of 2 and
  redesign deck with safety factor of 1.5

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STAY CABLE DATA

• Longest cable L 990m H 233m

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DECK DATA
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CABLE-STAYED RESULTS

• 99 stay cables with diameters ranging from 10cm
  (cable 99) to 16.0cm (cable 64)
• F ranges from 25MN to 3083MN
• Adeck ranges from 0.53m2 to 3.31m2
• Out of plane buckling safety factor is a problem

18
SUSPENSION VS CABLE-STAYED

• Deck and cable weight on one tower increases from
  2(598MN) 1196MN for suspension bridge to
  2(1059MN) 2118MN for cable-stayed bridge.
  Tower size must be increased accordingly.
• This additional 922MN is in cable and deck steel
  only. Total cable and deck steel on half of the
  suspension bridge is 559MN.
• Clearly, the suspension bridge is superior.