Deon S. Thelwell

Deon Thelwell is the Geotechnical Construction Practice Leader for the East Region of GEI. He has extensive experience in the construction of slurry walls, secant walls, drilled shafts, jet and compaction grouting, micropiles, and other ground improvement and deep foundation systems. He has provided Quality Control and Quality Assurance field testing of earthwork and construction materials, monitored activities in construction related operations, monitored foundation installation, and evaluated foundation soils. He has also served in Quality Control, Quality Assurance, and Special Inspector roles for work related to the installation of fireproofing, rebar and structural steel, reinforced concrete, the placement and stressing of post tension cables for cast-in-place and pre-cast concrete members and other building code related items.

Mr. Thelwell also has extensive experience in in-situ testing and as an instrumentation specialist for geotechnical, geophysical, and structural investigations. He has designed and conducted nondestructive and nonintrusive surveys using a wide range of survey methods that include, but are not limited to, Pressuremeter Testing (PMT), Dilatometer Testing (DMT), Cone Penetration Testing (CPT), Ground Penetrating Radar (GPR), magnetometers and conductivity/resistivity meters, Cross-hole Sonic Logging (CSL), Impulse Response Spectrum test, Pile Integrity Test (PIT), Parallel Seismic, Cross-hole Velocity test (Shear wave testing), and Vibration Monitoring. He has designed, conducted, and monitored dynamic and static load tests for deep foundations. He has also conducted façade inspection on several buildings over 30 stories and has performed non-destructive testing on concrete silos and smokestacks up to 600 feet tall for power plants and paper mills throughout United States.