Local measurement of radial strain in triaxial apparatus: A new device

To allow the precise measurements of radial strain locally on the cylindrical specimen in a triaxial apparatus during the first stages of a test, but so that the test could be continued up to higher strains, a new device was constructed. The device uses a pair of local deformation transducers propped between the tips of two light but stiff enough bars, fixed at their middle points to two opposite points of the specimen, on the middle of its height. The construction of the device is presented together with the measurement on a dummy.