Jim D. Wiethorn, P.E.

Haag Engineering Co.


Jim D. Wiethorn has been involved in the design, construction, and evaluation of residential, commercial and industrial buildings since 1973. His experience has included evaluation and assessment of damage and failure of all construction types and systems, in particular, crane accidents and operations. His construction background includes involvement as a third generation general contractor in the family business, as well as Certificate of Competency as a General Contractor in Florida, by exam. Mr. Wiethorn has owned and operated cranes while working in the construction industry and has evaluated over 850 crane and rigging failures throughout the United States and abroad. Currently, he serves on the National Commission for the Certification of Crane Operators (NCCCO), Tower Crane Committee, and Rigger Task Force Committee dealing with the testing and certification of crane operators and rigging. Additionally, Mr. Wiethorn is a member of the American Society of Mechanical Engineers (ASME) B30 Main Committee; and, B30.3, Tower Cranes, and B30.29, Self-Erecting Tower Cranes sub-committees. In 2014 Mr. Wiethorn published, Crane Accidents: A Study of Causes & Trends to Create a Safer Work Environment, 1983-2013, which detailed results of the study of over 500 crane accidents. Mr. Wiethorn is a Principal Engineer and Chairman of the Board of Haag Engineering Co. based out of the Houston, Texas office. Mr. Wiethorn is currently licensed as a professional engineer in 35 states and has testified in over 120 trials and 300 depositions.