Describe the design process that was used to develop the preferred bridge type.

The engineering team looked the following design elements:

• Girder type (precast concrete or steel)
• Girder size (longer spans require larger girders)
• Span lengths
• Bridge height over the river
• Girder spacing

Over 1,500 different combinations of these elements were compared by cost and narrowed down to a small group of feasible bridge types. This group was studied in detail considering additional factors such as:

• Future maintenance costs
• Environmental issues
• How the cost of the entire project was affected by the bridge alternate
• Aesthetic considerations

Out of this more detailed analysis a single bridge type was developed. The optimum bridge type is the alternate that is cost effective to build and maintain, creates the least impact on the environment, and provides the greatest opportunity for aesthetic enhancement.