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Historic 3rd Avenue Bridge nears completion

Historic 3rd Avenue Bridge nears completion

COWI in North America is nearing completion of its rehabilitation work as the
construction engineer for Ames Construction on the historic Third Avenue Bridge,
located in Minneapolis, over the Mississippi River. The landmark structure carries
road traffic across the Mississippi River and upper fringes of Saint Anthony Falls
and can be considered a major access point for the U.S. Bank Stadium, home of
the Minnesota Vikings. According to the Minnesota Department of Transportation
(MnDOT), it is the last major reinforced-concrete Melan arch bridge constructed
in the Twin Cities and is protected for its historic integrity and architectural
qualities.

The multi-span Melan arch bridge meets with Third Avenue in downtown
Minneapolis at its south end, but curves as it crosses the river, and connects
with Central Avenue on its north end. The shallow “S” curve in the bridge was
built to avoid fractures in the limestone bedrock that supports 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 Bridge Integrated Model, and engineering support.

COWI utilized its innovative Bridge Integration Modeling (BrIM) approach during
the pre-construction of this Construction Manager-General Contractor (CMGC)
project to assist in the visualization of the step-by-step construction phases
proposed. The BrIM process has helped the construction team proceed with the
integration of the complex construction sequencing, scheduling, and planning for
upcoming construction activities.

COWI began the construction engineering work for the bridge in 2019 and the
work includes the re-decking and rehabilitation of the bridge to achieve a 50-
year design life, whilst preserving its historic design elements. During
reconstruction, the main goals were to minimize the impacts on the local
community and the environment, while reducing the closure of this important
artery of downtown Minneapolis. There are also barriers, railings and lighting
added to the bridge, as well as minor grading at the bridge approaches.

Ivan Liu, Project Manager, COWI, 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.

In Pre-Construction phase of the project, FINLEY used a 3D bridge integrated
model to develop the visualization for many proposed construction sequences to
provide the CMGC group the necessary tools to select the right construction
method to avoid potential issues and clashes that may occur during construction.

The Bridge Integrated Model in the 3D environment was an effective tool to help
the major parties of this CMGC project visualize what could be feasible and
successful for the project’s complex construction sequence. For FINLEY, the use
of the bridge integrated model proved to be an efficient tool for multiple
construction engineering tasks especially when it involved aspects of the Third
Avenue Bridge’s complex geometry.”