LoadTrac II/FlowTrac II RC-TS

Geocomp's resonant column and torsional system is based on the Long-Tor Resonant Column Apparatus developed by Dr. Vincent P. Drnevich (patent 1974) at Purdue University. The LoadTrac II/FlowTrac II RC-TS system is a fully automated system designed to measure the shear modulus and damping of soils at strains down to 10^-7. The unit completely automates saturation, consolidation, resonant column, torsional shear, and stress-path test phases. The system consists of a computer-controlled unit that utilizes an oscillator motor to apply cyclic torsional loading to the top of the specimen for a range of excitation levels. Unlike other systems, a direct torque measurement is made at the bottom of the specimen to completely eliminate issues of back emf. Resonant column and torsional shear testing can also be followed by a stress-path triaxial test. The system is capable of displaying the current status of a test and graphically portraying the progress of the test in real time.

Applicable Test Standards

• ASTM D4015, D4767
• AASHTO T 297

Features

• Option to perform torsional cyclic shear for studying cyclic strength and liquefaction
• Option to independently measure low strain shear modulus and compression modulus with piezoelectric sensors
• Option to measure post-liquefaction shear strength
• Measures resonance frequency, damping ratio, and shear modulus in torsion
• Fully-automated and unattended back-pressure saturation, consolidation, resonant column, torsional shear, and axial shear phases
• Capable of performing
  • Torsional shear within a range of frequencies from 0.033 Hz up to 50 Hz with strain and up to 10 Hz
  • Strain/stress-controlled and earthquake motion or user-defined irregular loading/strain tests
  • Triaxial or stress path shear test after torsional shear or resonant column test
• Integrated low-force (counter-balanced) lift mechanism for removing chamber
• Complete protocol flexibility to intermix automated test phases