The Executives

Dennis A. Sack, P.E.

Senior Vice President and Principal Engineer

Before joining Olson Engineering (OE) in 1990, Mr. Sack had been with Northrop Aerospace as a Wind Tunnel Instrumentation Engineer. He earned his Bachelor of Science in Electrical Engineering at Cal State University, Northridge, California Magna Cum Laude and completed all of the course work of the Masters in Electrical Engineering program (Digital Signal Processing) at Cal State Northridge. Mr. Sack has a broad range of experience in NDT and evaluation of structural elements of various materials. He has extensive consulting experience in over 3800 nondestructive evaluation, vibration and geophysical investigations. In addition to his consulting service ability, Mr. Sack has been responsible for the design and development of instrumentation, both hardware and software, for over 20 years for Olson Instruments (OI). He has designed and built the electronics for the Olson Instruments Freedom Data PC, Concrete Thickness Gauge, and NDE360, as well as associated transducers, pulser units and software for ultrasonic, sonic, seismic, vibration and physical testing measurements. Mr. Sack holds a patent in Scanning Apparatus and Method for Non-Destructive Materials Evaluation and Mapping Through Use of Acoustic Waves. Mr. Sack's responsibilities as Senior Vice President are varied. He supports the OE Consulting Group as well as the OI Design Group in the Colorado Office. Mr. Sack has prepared and presented a number of papers on a variety of aspects related to NDT of infrastructure, and is currently an instructor for the ASCE seminar on Structured Condition Assessment of Existing Structures.

Engineering Employee


  • Colorado
  • Oklahoma
  • Nebraska
  • New Mexico
  • Wyoming


  • "Improving Dam Safety Through the Use of Nondestructive Evaluation", Dennis Sack, Larry Olson, Dam Safety Conference, Indian Wells California, September, 2008
  • "In-Place Nondestructive Evaluation of Foundations of Unknown Type and Depth", Dennis Sack Larry Olson, Dr. Yajai Tinkey, Stress Waves 2008 Conference Proceedings, Portugal, 2008
  • "Applications of Stress Waves Nondestructive Methods of Building and Bridges", Marwan F. Aouad, Ph.D., Larry D Olson, P.E., and Dennis A. Sack, Structural Engineers World Congress, San Francisco, California, July 18-23, 1998.
  • "NDT Diagnosis of Drilled Shaft Foundations", Larry D. Olson , P.E., Marwan F. Aouad, Ph.D., P.E., and Dennis A. Sack, Transportation Research Board, 77th Annual Meeting, Washington, D.C., January 11-15, 1998.
  • "A Comparison of the Performance of Several Impact Echo Transducers and Application of Impact Echo NDT to the Lincoln Memorial in Washington, D.C.", Dennis A. Sack, Larry D. Olson, P.E., and David Fidelman, Proceedings of the Seventh International Conference on Structural Faults and Repair, July 10th 1997.
  • "High Speed Testing Technologies for NDT of Structures", Dennis A. Sack and Larry D. Olson, P.E., International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE), Berlin, Germany, September 26-28, 1995.
  • "Nondestructive Evaluation of Concrete Dams and Other Structures", Larry D. Olson, P.E., and Dennis A. Sack, Nondestructive Evaluation of Aging Infrastructure, sponsored by SPIE, The International Society for Optical Engineering, Oakland, CA, June 6-8, 1995.
  • "Impact Echo Scanning of Concrete and Wood", Dennis A. Sack, Larry D. Olson, P.E. and Marwan F. Aouad, Nondestructive Evaluation of Aging Infrastructure, sponsored by SPIE, The International Society for Optical Engineering, Oakland, CA, June 6-8 1995.
  • "High Speed NDT of Concrete Using Impact Echo Scanning", Dennis A. Sack, Larry D. Olson, P.E., 10th Engineering Mechanics Specialty Conference, University of Colorado at Boulder, Boulder, Colorado, May 21-24, 1995.
  • "Evaluation of Pavement Systems Using the Spectral-Analysis-of-Surface Waves (SASW) Method", Marwan F. Aouad, Kenneth H. Stoke, Larry D. Olson, P.E., and Dennis A. Sack, Proceeding Second International Conference on Road & Airfield Pavement Technology, Singapore, September 27-29, 1995.
  • "In-Situ Nondestructive Testing of Buried Precast Concrete Pipe", Dennis A. Sack, Larry D. Olson, American Society of Civil Engineering, proceedings Materials Engineering Conference, November 1994.
  • "The Use of Impact-Echo and Spectral-Analysis-of-Surface-Wave Methods for the Concrete Investigation of the Rogers Dam Spillway Structure", Larry D. Olson, Y. Fai Chan, Dennis A. Sack, Michael F. Dumont, Robert T. Gilmore, John T. Christy, Proceedings of the 56th American Power Conference, April 1994, Chicago, Illinois.
  • "Stress-Wave Nondestructive Testing of Tunnels and Shafts", Larry D. Olson, Dennis A. Sack, Kenneth H. Stokie, II, and Kenneth W. Buchinski, Transportation Research Board-Annual Meeting- Session on Nondestructive Testing of Deteriorating Infrastructure, Transportation Research Record 1415, Washington, D.C. January 1993, p.88-94.
  • "Advanced NDT Methods for Evaluating Concrete Bridges and Other Structures", Dennis A. Sack, Larry D. Olson, Structural Faults + Repair-93, 5th International conference and Exhibition, University of Edinburgh, Scotland, UK,, June-July 1993.
  • "Advanced NDT Methods for Concrete Structures", Dennis A. Sack, Larry D. Olson, Proceedings of the International Conference on Nondestructive Testing of Concrete in the Infrastructure, sponsored by the Society for Experimental Mechanics, Inc., Dearborn, Michigan, June 1993.
  • "Innovations for NDT of Concrete Structures", Larry D. Olson, Dennis A. Sack, Gregory C. Phelps, Proceedings of ASCE Specialty Conference: 1992 Materials Engineering Congress, Atlanta, Georgia, August 1992.
  • "Nondestructive Testing of Older Concrete Bridges: A Case History of the SEPTA Manayunk Bridge", Dennis A. Sack, Larry D. Olson, Thomas R. Kline, Gregory R. Yates, Proceedings of the International Bridge Conference, Pittsburgh, Pennsylvania, June 1992.
  • "Sonic NDE of Bridges and Other Concrete Structures", Larry D. Olson, Dennis A. Sack, Gregory C. Phelps, Nondestructive Evaluation of Civil Structures and Materials Conference, National Science Foundations, Boulder, Colorado May 1992.