The bridge carries road traffic across the Mississippi and upper fringes of Saint Anthony Falls and is a major access point for the US Bank Stadium, home of the Minnesota Vikings football team.
According to the Minnesota Department of Transportation the Third Avenue Bridge is the last major reinforced-concrete Melan arch bridge constructed in the Twin Cities (Minneapolis-Saint Paul) and is protected for its historic integrity and architectural qualities.
The Melan System was a method for the construction of reinforced bridges using rigid iron truss arches instead of reinforcing bars embedded in the concrete. It is named after its inventor, Austrian engineer Josef Melan, who died in 1941.
The multi-span Third Avenue bridge connects Third Avenue on the south bank with Central Avenue to the north. It was designed to follow a shallow ‘S’ curve as it crosses the river in order to avoid fractures in the limestone bedrock supporting the bridge piers.
Cowi was responsible for the staged construction analysis of the existing and new bridge structure, design of the temporary falsework, production of the fabrication drawings for the concrete elements, geometry control for casting, development of the 3D BIM model, and engineering support.
Cowi employed its proprietary Bridge Integration Modeling (BrIM) system during the pre-construction phase to create a step-by-step visualisation of the proposed construction sequence.
Engineering work on the bridge started in 2019 and included replacement of the bridge deck and rehabilitation work to achieve a 50-year design life.
Cowi project manager Ivan Liu said: “The unique aspect of the Third Avenue bridge is its intricate demolition and reconstruction sequence performed on the existing structure. Due to the variety of construction limitations from bridge access issues, structural capacity concerns, and equipment loading, it led to a multi-phase construction sequence for its complex bridge geometry.”