I-25 – Speer to 20th Street/15th Street Bridge

Denver, Colorado

The Tsiouvaras Simmons Holderness team successfully designed the 15th Street bridge replacement with an increase in vertical clearance over I-25 while maintaining the vertical profile of 15th Street. Another challenge overcome was an increase in span length by 50 feet, while maintaining a thin superstructure. The complex design required extensive experience and knowledge with structural analysis and time-dependent modeling to accurately predict bridge girder camber. TSH also provided inspection of the fabrication of the steel plate girders for the two-span bridge TSH coordinated with the steel fabricators to inspect the girders as they were being assembled at the fabrication plant in South Dakota to assure compliance of all production tolerances and limits. Fabricator quality control procedures were reviewed, and solutions developed for any issues that arose during assembly and fabrication.

  • Designed steel plate girder camber to match the roadway profile
  • Included both soil nail and tangent caisson walls
  • Increased the bridge span length by 50 feet using a thin superstructure
  • Analyzed superstructure using time-dependent modeling to accurately predict bridge girder camber