Wire rope, also called cable, consists of several strands of metal wire twisted into a helix. Wire rope generally refers to diameters larger than 3/8 inch, while smaller diameters are called cables or cords. Steel is the most common material used in wire ropes today. Individual wires are first twisted into strands, then several strands are twisted around a core to cushion stress forces during bending. Common configurations include 6x19 and 7x7. Cables are used in structural applications like suspension bridges, cable stayed bridges, roof structures, and glass walls. Suspension bridges hang the deck below suspension cables attached to towers, while cable stayed bridges support the deck with cables running directly from one or more towers.
2. CABLES
(WIRE ROPE)
• The term cable is often used interchangeably
with wire rope.
• Wire rope is a type of cable which consists of several
strands of metal wire laid (twisted) into a helix.
• However, in general, "wire rope" refers to diameter
larger than 3/8 inch (9.52 mm).
• Sizes smaller than this are designated cable or cords.
3. MATERIALS
Initially wrought iron wires were used, but
today steel is the main material used for wire
ropes.
Stainless steel:-
Used where corrosion resistance is
prime factor.
Galvanized carbon steel :-
Used where strength is prime factor.
4. Structure
Individual wires are first
twisted into a strand
then six strands are twisted
around a core which is used
to cushion off stress forces
when bending the rope.
5. (No of strands x No of wires in a strand)
6x19 cable
7x7 cable
7x19 cable
6. USES OF CABLES
Structural uses:-
• Suspension bridges
• Cable stayed bridges
• Long span roof structure
• Inflatable membrane roofs
• Elegant railings
• Cable net glass walls
7. Suspension bridge
• A suspension bridge is a type of bridge in which
the deck (the load-bearing portion) is hung below
suspension cables on vertical suspenders.
• This type of bridge has cables suspended
between towers, plus vertical suspender cables
that carry the weight of the deck below, upon
which traffic crosses. This arrangement allows the
deck to be level or to arc upward for additional
clearance.
8.
9. Load transfer mechanism
In suspension bridges, large main cables (normally 2)
hang between the towers (normally 2), and are anchored
at each end to the ground. This can be difficult to
implement when ground conditions are poor. The main
cables, which are free to move on bearings in the towers,
bear the load of the bridge deck. Before the deck is
installed, the cables are under tension from their own
weight. Along the main cables smaller cables or rods
connect to the bridge deck, which is lifted in sections. As
this is done, the tension in the cables increases, as it does
with the live load of traffic crossing the bridge. The
tension on the main cables is transferred to the ground
at the anchorages and by downwards tug on the towers.
10.
11. Cable stayed bridge
• A cable-stayed bridge has one or more towers
(or pylons), from which cables support the
bridge deck.
14. Load transfer mechanism
In the cable-stayed bridge, the towers are the primary load-
bearing structures which transmit the bridge loads to the
ground. A cantilever approach is often used to support
the bridge deck near the towers, but lengths further from
them are supported by cables running directly to the
towers.
This has the disadvantage, compared to the suspension
bridge, that the cables pull to the sides as opposed to
directly up, requiring the bridge deck to be stronger to
resist the resulting horizontal compression loads; but has
the advantage of not requiring firm anchorages to resist
the horizontal pull of the main cables of the suspension
bridge.
15. By design all static horizontal forces of the
cable-stayed bridge are balanced so that the
supporting towers do not tend to tilt or
slide, needing only to resist horizontal forces
from the live loads.
19. Inflatable membrane roofs
A low cost method and device for diverting
water away from a flat roof's low spots, thus
preventing it from puddling there during a
rainstorm.
20. Other use :-
i. Cable transport
ii. Elevators
iii. Cranes
iv. Tightrope walking
v. Cargo derrick
21. Cable transport
Cable transport is a broad class of transport
modes that have cables as foundation for
transporting things, people, or vehicles.
The cable may be driven or passive; items may
be moved by pulling, sliding, sailing, or by drives
within the object being moved on cableways. The
use of pulleys and balancing of loads going up
and down are common elements of cable
transport.
They are used in mountainous areas.
24. Cranes
A crane is a type of machine, generally
equipped with a hoist rope, wire ropes or
chains, and sheaves, that can be used both to
lift and lower materials and to move them
horizontally.
25. Tightrope Walking
Tightrope walking, also called funambulism, is the
art of walking along a thin wire or rope. It has a
long tradition in various countries and is
commonly associated with the circus.
