OPAC Consulting Engineers

Hoover Dam Bypass: Colorado River Bridge



Obayashi/PSM, JV
Jeff St. John,
Project Manager
Tel (702)293-4923
email jeffsj@obayashi-usa.com


Construction completion 2010

Scope of work:

Construction Engineering

Construction cost (estimated):

US $114 million

Services Performed:

  • Prepared integrated drawings
  • Prepared erection method proposal
  • Performed stage by stage erection analysis
  • Prepared erection manual
  • Provided geometry control support
  • Construction engineering support


  • Challenging construction site
  • Complex construction staging
  • Required nonlinear, inelastic stage by stage analysis
  • Strict erection geometry control

The Colorado River Bridge will carry U.S. Highway 93 across the Colorado River between Nevada and Arizona, approximately 1500 feet downstream of the Hoover Dam. The Composite Concrete Deck Arch Bridge will have a main arch span of 1,090 ft and side spans of 480 ft and 220 ft. The 88 ft wide deck consists of steel box girders supporting a cast-in-place concrete deck. The concrete arches are intended to be erected by segmental cantilever method utilizing temporary towers and stay cables. The columns will be erected by precast segmental method. OPAC was engaged by the contractor (Obayashi-PSM, JV) to provide the following engineering services during erection:

  • Prepare erection method proposal
  • Design temporary supports or bearings
  • Develop erection sequence, procedure and construction loads
  • Prepare integrated concrete segment drawings
  • Develop casting curves
  • Check segment handling
  • Check erection equipment
  • Design temporary erection structures
  • Perform 3-D erection analysis
  • Develop manual of erection procedures