Ram extensiometer - has flexible strip between bracket and ram pressure measuring device

The ram (1) fixed to the structure (2) whose strain is to be measured and a bracket (11) fixed at another position on the structure are connected by a flexible strip (10). The piston (4) of the ram may be subjected to a fluid pressure and can be displaced until stopped by a shoulder (1a) in the ram cylinder (1) and until a stop (8) comes against a surface (1b) of the ram. A strain gauge (12) is fixed to the strip (10) to measure its elongation. A measure of the extension of the base (1s) of the device is made by determining the difference between the pressure in the chamber (14) of the ram (1) before and after a load has been applied to the structure, and also the difference in pressures required to bring the piston at both ends of its travel.