The Third Avenue Bridge, spanning the Mississippi River in downtown Minneapolis, Minnesota, was originally designed and constructed in the early 1900s, and placed on the National Register of Historic Places for its historic and engineering significance.

The Minnesota Department of Transportation’s Third Avenue Bridge rehabilitation project, initiated to address the structure’s deteriorated conditions and extend its service life, required close coordination between HNTB and MnDOT’s Cultural Resources Unit and the State Historic Preservation Office.

HNTB was responsible for the final design of this complex bridge rehabilitation project and served as an extension to the client during construction. The bridge's construction consisted of two steel spans over West River Road, five spans of three concrete deck arch ribs over the river, two spans of concrete deck barrel arches over the river and two prestressed concrete girder spans over Main Street. All elements above the arches were replaced, and to protect the remaining elements, the concrete was structurally evaluated through a rigorous analysis process. Work was completed with tower cranes due to the sensitivity of the arches, allowing the work to be completed in a top-down fashion from the deck level

The rehabilitated bridge’s design includes enhanced historic and visual features that honor the original, 20th century vision.

But the structure doesn’t only pay respect to past. Improvements also include a smoother road surface that provides motorists’ greater ease. Users of the restored bridge will enjoy a smoother road surface, improved safety and accessibility features including new lighting and the addition of 13-foot wide pedestrian and bicycle paths on both sides of the bridge.

With rehabilitations completed and the bridge re-opened to the public, the Third Avenue Bridge has improved mobility and restored rightful connection for years to come.

Location: Mississippi River in Minneapolis, MN

Client: Minnesota Department of Transportation

Awards: 2022 Top 10 Bridges, Roads and Bridges; 2024 Grand Conceptor Award, ACEC Minnesota