10. Methods and Means for Measuring Cables Tension

The measurement of cable extension is a complex problem needing special mechanical tests and modern measurement means, particularly important for the safe functioning of some installations in which human values and special materials are involved. The mechanical tests on cables usually refer to their modulus of elasticity and breaking limit establishing. At the Laboratory for Research and Testing of Materials from the Polytechnic Institute of Bucharest an experimental rig has been set up permitting the automatic plotting of force versus deformation curves for conductors loaded in tension. Tests are performed on a Werder-type universal testing machine of 1 MN, with horizontal axis, modernized by addition of a hydraulic drive and a chain for the measurement and simultaneous recording of forces and displacements. Another example is the automatic measurement system for ground anchor proof testing in Portugal.