This project replaces the 100-year-old I-74 twin bridges over the Mississippi River with new twin basket-handle, true-arch bridges. The difficulties in successfully completing the staking and layout on a project with no margin for error were numerous. This includes overcoming a maximum bridge height of 300 feet above the Mississippi River’s surface, constantly working over an active waterway that makes control difficult, a requirement for error-free, zero tolerance work, and no shoring platforms.
Before a single arch piece could be installed, a solid and precise foundation was needed. From a remote location, we built precise 3D models of the foundation and the arch pieces. We devised a method for designing the concrete substructure to match the batter of the arches, utilizing surface models for layout to ensure concrete forms were accurately placed.
To ensure precise installation with zero tolerance, Kapur set Leica 360 prisms on each arch piece and the existing bridge channel piers, collaborating with the rigging design to ensure the prisms were properly located and survey data would have the highest possible integrity.
- Staking and layout
- 3D modeling
- Elevation verification
The successful placement of the keystone arch section was the culmination of Kapur’s “All In” approach that we take toward every project.
The two river crossing arches have now been completed. The westbound span was completed on November 13, 2020, and the eastbound span was completed on December 3, 2021.
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