CABLES

CABLES

Cables are the flexible structure which offers zero resistance to shear or bending. These are the structures which are used to support suspension bridges, cable car system etc.…Generally cables are subjected to tensile forces. If the cables are unstiffened, then due to the impact of external load the cable takes funicular shape.

Types of cables

Basically, there are two types of cables

Suspension type cable

• These are the cables which run freely through the towers transferring loads through the anchorages at each end.

• It must have two towers to work effectively.

• It can only support straight bridge

Stayed type cable 

• These are the cables which runs directly from roadway to the single towers on which the load acts.

• It can only have single tower to work efficiently.

• It can support curved bridge.

Assumptions for analysis of cable structures

1.     Self-weight of the cable structure is neglected

2.     Cables are subjected to tension force.

3.     Cables will have zero shear force and bending moment.

4.     Cable structure will have constant young’s modulus throughout.

5.     Cables can be subjected to any type of loading except external moment.

6.     The length of unloaded cable is always constant.

7.     Cables can have large displacements (say v) with only small gradients(dv/dx).