A very well-respected specialty geotechnical contractor. They have a number of nice technical articles and case studies published on their website.
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Hatch Mott MacDonald
A full service engineering firm with much experience in tunneling. Visit Hatch Mott MacDonald
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Geophysical Survey Systems
Geophysical Survey Systems, Inc. (GSSI), is the world leader in the development and manufacture of commercial ground penetrating radar (GPR) systems and electromagnetic induction instruments (EM). Visit Geophysical Survey Systems
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GRL Engineers, Inc.
Consulting engineers based in Cleveland, OH with expertise in testing and analysis of deep foundations: dynamic load testing, pile driving monitoring, integrity testing, CSL, wave equation analysis, SPT hammer performance. Visit GRL Engineers, Inc.