As part of an industry funded project (Electric Power Research Institute), a large scale biaxial testing facility was assembled. Starting with an existing million pounds servo-controlled MTS testing machine, two additional horizontal actuators, each with a capacity 120 kips in tension and 150 kips in compression were installed. Each of the three actuators is in turn separately controlled by an analogue MTS controller, providing the experimentalist with endless possibilities. Two horizontal actuators were selected instead of a single one to provide better (independent) control for uniform stress fields, or to facilitate the application of a stress gradient.

The specimens tested so far had cross-sectional dimensions of 30 by 10 inches, for which shear stress upto 1,000 psi and normal stresses upto 500 psi in compression and 400 psi in tension could be applied.

It is anticipated that with minor modifications, dynamic tests could also be performed. Shear stress upto 1,000 psi and normal stresses upto 500 psi in compression and 400 psi in tension can be applied on our specimens.

Compression-Shear Tests

Depending on the arragements of the setup, the following tests can be conducted: tension, compression-compression, tension-tension, shear-compression, shear-tension.

Direct Tension Test

This set-up could be used to investigate the static/fatigue/dynamic response of biaxialy loaded concrete/rock specimens, steel connections, mixed mode fracture, confined pull-out anchors, base isolators. Industrial partnership is being sollicited.