I-35W Bridge Reconstruction Project

I-35W Bridge Reconstruction Project


Project Challenge

On Aug. 1, 2007, the Interstate 35W Bridge over the Mississippi River at the edge of downtown Minneapolis near St. Anthony Falls collapsed. The bridge carried more than 140,000 vehicles a day; the loss of the bridge cost roughly $400,000 per day in lost revenue, increased commuter expense and over-burdened surrounding roads.

The I-35W St. Anthony Falls Bridge was one of the most highly visible, fast-paced
construction projects in recent years. Rani Engineering was brought into the project in
February 2008, just as construction staking of the superstructure began. The schedule of
designing and building the bridge in 14 months required Rani Engineering to have surveyors on-site 24 hours a day, seven days a week. Rani Engineering’s six field technicians logged more than 9,000 man-hours in their first five months on the project.

Rani Engineering Solution

Rani Engineering provided professional survey services including:

  • Staked bridge superstructure elements 24/7 as needed for construction
  • Set accurate (to 0.001?) project control
  • Checked forms for build accuracy before major concrete pours
  • Coordinated with superintendents for all aspects of construction
  • Collected topographic/as-built survey information
  • Found in Place (FIP) – final project as-builts
  • Field work completed despite snow and ice conditions during February to April 2008 and winter 2008-09


Construction survey work was performed using a combination of Trimble GNSS GPS units and other traditional methods.