Experiments

  • Determination of the catenary of a free-hanging cable
    • under dead-weight only
    • with additional weights
    • with a symmetrical setup (chain wheels at same height)
    • with an unsymmetrical setup
  • Measurement of the sag.
  • Comparison of calculated and measured values.

Specifications

  • Determination of the catenary of a free-hanging cable.
  • Symmetrical and unsymmetrical experimental setup possible.
  • Roller chain as cable with 2 ball bearing-mounted chain wheels.
  • Adjustable chain wheel axle spacing.
  • Height of a chain wheel adjustable for unsymmetrical experimental setup.
  • Cross-arm with scale to hold chain wheels and rule to measure vertical sag of chain.
  • 2 graduated weight sets.
  • Storage system to house the components.
  • Experimental setup in frame.

Free-hanging cables and ropes are often used to support a structure, such as stay cables. On suspension bridges they are the load-bearing element of the structure. In many calculations the influence of the deadweight of the cable can be ignored, because it is low compared to the other loads. In the case of overhead power lines, however, the deadweight of the cable is relevant to the design of the pylons.

In Cable Under Dead-Weight a free-hanging cable under the influence of its own deadweight is investigated. A roller chain serves as the cable, and is mounted on two ball bearing-supported chain wheels. The chain wheel units are fixed to a cross-arm. The spacing between the chain wheel axles can be adjusted horizontally and vertically. Weights can be attached to both ends of the chain. The maximum sag is measured using scaled rules, and can be compared with calculated values. The sag is the distance between the connecting line of the bearings and the catenary.

All the component elements of the experiment are clearly laid-out and housed securely in a storage system. The complete experimental setup is arranged in the frame.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments frame.