Introducing the LoadTrac III
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 An embedded control board with a dedicated CPU takes readings from the force transducer and displacement transducer to control the micro-stepper motor.
The base unit includes built-in data acquisition and display capability. Sensor readings are displayed in SI or English units and stored in memory. For incremental consolidation, the base unit is linked to a PC, using the built-in high-speed network and the appropriate software running on the latest Windows OS, including Vista. This completely automates the test, reduces the data and prepares the final test results in graphical and tabular formats. The data is also available in multiple formats as raw, engineering, or processed.
Other options include running constant rate of strain consolidation. 
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Who’s New
Joining GeoTesting Express as a senior technician is Fazlul Mir Karim. Most recently, Karim was an engineering geologist with ESPL Environmental Consultants in New York. Originally from Bangladesh, Karim worked more than 20 years for the Geological Survey of Bangladesh in various directorial capacities. His experience includes geological mapping, exploratory drilling, geotechnical investigation, laboratory testing, and seismological work. Karim has an MS in geological exploration methods from Nottingham University in the UK. He earned an MS and BS in geology from Dhaka University in Bangladesh.
Dr. Hyun-Ki Kim is the newest member of Geocomp’s Georgia office. He earned his Ph.D. in geosystems engineering from the Georgia Institute of Technology, where he held a position as a post-doctoral fellow. Dr. Kim recently did research on the scale effects of soil behavior and on the performance of inverted base pavement with Dr. Carlos Santamarina. In addition, Dr. Kim completed a flow test evaluation for the Georgia Department of Transportation. At Geocomp, Hyun-Ki will direct the geosynthetic testing program, including fullscale box testing of pavement sections with geosynthetic reinforcement in the subgrade. 
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From the Lab
Direct Simple Shear Test
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taken for DSS testing. The DSS tests provide the anchor point with which to evaluate all data and obtain the best estimate of undrained shear strength for design. This approach allows one to use lower factors of safety with less risk because there is less uncertainty in the design shear strength.
The ASTM standard for the DSS test is D 6528. In the test, a circular specimen with a diameter of 2.5” and height of 1” is trimmed into a wire-reinforced rubber membrane and constrained axially (between two platens) and laterally to produce Ko conditions during consolidation. The specimen is then incrementally consolidated. After completion of consolidation to the chosen vertical effective stress,
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shearing is induced in the specimen by horizontally displacing one of the end platens at a constant rate. The normal load applied to the specimen is adjusted to maintain a constant volume. The measured peak shear stress is used in stability analysis.
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GeoTesting Express can perform DSS and cyclic DSS testing, including post-cycling shear strength, using automated equipment from Geocomp Corporation. We have been performing direct simple shear tests for years in support of some high-profile, challenging geotechnical projects including the 17th Street Canal failure investigation in New Orleans, and the Port of Anchorage project in Alaska.
Ladd, Charles C. and DeGroot, Don J.
(2003). “Recommended Practice for Soft
Ground Site Characterization: Arthur
Casagrande Lecture.” Soil and Rock
America – 12th Panamerican Conference
on Soil Mechanics and Geotechnical
Engineering
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