Long Span Cable in Construction

1. SPAN
STRUCTURE
GROUP MEMBERS
M. DANIAL MAULA ABU BAKAR - 2012617322
AHMAD FAIZ BIN ABD KARIM - 2012850668
WAN NOOR AZEAN BT WAN MAHMUD - 2012601764
NURUL FARHANA BT NORROL AKHLA - 2012469216

2. CABLE SYSTEM
 MAJOR SYSTEM
Form active structure systems
Non rigid, flexible matter shaped in a certain way and secured
by fixed ends, support itself & span space. The transmit loads
only through simple normal stresses, either tension or through
compression.
 Two cables with different points of suspension tied together
form a suspension system. A cable subject to external loads
will deform in a way depending upon the magnitude and
location of the external forces. The form acquired by the
cable is called the FUNICULAR SHAPE of the cable.

3.  Form Active Structure Systems redirect external forces by
simple normal stresses : the arch by compression, the
suspension cable by tension. The bearing mechanism of form
active systems vests essentially on the material form.

4.  The natural stress line of the form active tension system in the
funicular tension line.
 Any change of loading or support conditions changes the
form of the funicular curve.

5. MATERIAL
 Steel Cables : The high tensile strength of steel combined with
the efficiency of simple tension, makes a steel cable the ideal
structural element to span large distances.
 Nylon and plastics are suitable only
for temporary structures,
spanning small distances.

6. DYNAMIC EFFECTS OF WIND ON TYPICAL
FLEXIBLE ROOF STRUCTURE :
A critical problem in the design of any cable roof structure is
the dynamic effect of wind, which causes an undesirable fluttering
of the roof.

7. PREVENTIVE MEASURES :
There are only several fundamental ways to combat flutter.
• One is to simply increase the deal load on the roof.
• Another is to provide anchoring guy cables at periodic
points to tie the structure to the ground.
• To use some sort of crossed cable on double-cable system.

8. The principal methods of providing stability
are the following:
Additional permanent load
supported on, or suspended from,
the roof, sufficient to neutralize the effects
of asymmetrical variable actions or uplift
Figure 14 a)
This arrangement has the drawback that it
eliminates the lightweight nature of the
structure, adding significant cost to the
entire structure.
(ii) Rigid members acting as beams, where
permanent load may not be adequate to
counteract uplift forces completely,
but where there is sufficient flexural
rigidity to deal with the net uplift forces,
whilst availing of cables to help resist effects
of gravity loading (Figure 14b).

10. CASE STUDY
SINGLE-CURVATURE STRUCTURE
• The Akashi-Kaikyo Bridge also
known as the Pearl Bridge, has the
longest central span of any
suspension bridge in the world, at
1,991 metres (6,532 ft).
• The bridge has three spans. The
central span is 1,991 m
(6,532 ft), and the two other
sections are each 960 m (3,150 ft).
The bridge is 3,911 m (12,831 ft)
long overall.

11. • The steel cables have
300,000 kilometres
(190,000 mi) of wire: each
cable is 112 centimetres
(44 in) in diameter and
contains 36,830 strands of
wire.
Strands of wire Bridge girders
•The Akashi-Kaikyo bridge
has a total of 1,737
illumination lights: 1,084
for the main cables, 116 for
the main towers, 405 for the
girders and 132 for the
anchorages.
Illumination lights

12. DOUBLE-CABLE STRUCTURE
Bridge specifications
Overall Length: 13.5 km (8.4 mi)
Length Over Water: 8.4 km (5.2 mi)
Penang Island Viaduct & Approach: 1.5 km (0.93 mi)
Prai Approach: 3.6 km (2.2 mi)
Height of Tower Above Water: 101.5 m
Height of Bridge Above Water: 33 m
Main Span: 225 m
End Span: 107.5 m
Other Span: 40 m
Speed limit: 80 km/h
Maximum Gradient: 3.0%

13. CABLE STRUCTURE INFOMATION