Who We Are

Structural Design Corporation (SDC) is a licensed consulting engineering firm located in Libertyville, Illinois.  We have been providing engineering and inspection services since 1979.  We are a licensed design firm in the State of Illinois.

SDC has provided engineering services to the steel industry for over 30 years.  We excel in the design, upgrade, and rehabilitation of EOT Crane Runways and other mill structures across the United States and South America.

SDC has strong inspection and analytical skills.  These skills allow us perform forensic engineering services of structural issues.  We utilize our CRANE GIRDER PRO computer program to perform complete torsion and fatigue of crane girders.  SDC has completed the link between our field inspection findings and structural analysis results to determine the root cause of crane girder deficiencies.

Our Structural Inspection and Maintenance Manage System (SIMMS) allows SDC to provide condition based repair plans. A cost estimating module can generate repair costs for an individual building or the entire plant.  The severity of the deficiencies and associated repair costs can be provided for structures rated in Good, Fair, or Poor structural condition.

Structural Design Corporation (SDC) is operated by two Licensed Engineers, William Vanni PE and Junkan Fong SE.

William Vanni, President

Mr. Vanni is a licensed Professional Engineer specializing in the inspection, design and repair of structures, EOT cranes, tanks, vessels, and piping for firms in the power, steel, chemical, and petroleum industries.  Since 1988 he has provided inspection, engineering, and project management services to United States Steel, National Steel, Gerdau, SSAB, Nucor, Steel Dynamics, Thyssen-Krupp, and ArcelorMittal for their structural inspection programs which are required by OHSA.

Mr. Vanni is licensed to design seismic restraint systems in California.  His largest seismic design project was for the Central Plant piping in the Los Angeles County Jail.  The jail has a thermal energy system with 30” diameter piping from two (2) 34’-0” diameter ice tanks.

Mr. Vanni spent 2 years as a project manager for a subsidiary of Westinghouse Electric.  He was responsible for the management of the Electrical Discharge Machining (EDM) program to form new holes in the top former plate of nuclear reactors for the Upflow Conversion projects. 

Junkan Fong, Vice President

Mr. Fong is a licensed Structural Engineer specializing in engineering analysis and design.  He excels in the area of linear elastic and torsional stress analysis, seismic design, and database programming.  He provides analytical and design services to companies in the steel industry including United States Steel, National Steel, Gerdau, SSAB, Nucor, Steel Dynamics, and ArcelorMittal. 

His experience includes the design of structures, tanks, and piping for the chemical, pharmaceutical, and food industries using STAAD and other commercially available computer programs for performing structural analysis.  Mr. Fong discovered a critical error in the widely used STAAD program while performing a seismic analysis of a vessel for an oil refinery in Chile.  STAAD agreed with Mr. Fong and corrected the program.  All seismic designs previously made by other engineers are deficient. 

While at Sargent & Lundy he helped pioneer the BWR Mark III containment liner design for nuclear power plants.  This innovative design was awarded the 1983 Best Structure Award by the Structural Engineers Association of Illinois.  Mr. Fong also performed the mechanical stress analysis for Westinghouse of the robot arms used to repair two (2) nuclear reactors.  One arm was used to remove the lower core support assembly of the damaged reactor at Three Mile Island.  The other arm was used to repair the U.S. Department of Energy C-Tank Reactor located at the Savannah River Site.