Journal Published Online: 09 December 2016
Volume 40, Issue 1

Adaptation of Broadband Simple Shear Device for Constant Volume and Stress-Controlled Testing



We adapted an existing digitally controlled simple shear device, originally designed for drained testing with strain-control, to perform constant height testing under strain- or stress-controlled conditions. The re-designed system provided PID control of horizontal displacements or loads coupled with either vertical force or displacement control (for drained and constant-volume testing, respectively). The new system had substantially similar horizontal displacement control capabilities as the previous system. The tracking error under stress-controlled loading depends on amplitude and frequency of the load; however, its value was almost the same as errors in strain-controlled tests for common shear strain/stress amplitudes. High-precision vertical control was achieved during constant height testing in two respects: (1) height change was small (less than 0.05 % of the specimen height for large shear-strain tests), even at high frequencies; and (2) top cap rocking was small, with the vertical displacements due to rocking at the specimen edge being half or less than average changes in specimen height.

Author Information

Shafiee, A.
Shannon & Wilson, Inc., Glendale, CA, US UCLA Dept. of Civil & Environmental Engineering, US
Stewart, J.
Dept. of Civil and Environmental Engineering, Univ. of California, Los Angeles, CA, US
Venugopal, R.
US Technical Services, OPAL-RT Corp., Brighton, MI, US
Brandenberg, S.
Dept. of Civil and Environmental Engineering, Univ. of California, Los Angeles, CA, US
Pages: 14
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Stock #: GTJ20150181
ISSN: 0149-6115
DOI: 10.1520/GTJ20150181