City of Duluth

Superior Street Reconstruction

An iconic street reimagined

The mile-long Superior Street Reconstruction Project was a complete rebuild of one of Duluth’s oldest and most iconic streets, from Mesaba Avenue to Fourth Avenue East. Nearly every major utility within the corridor was replaced and several new major utility systems were added. With a total project length of over one mile, the project overlapped key connections between the downtown area, the Canal Park tourism and business district, and the Interstate 35 corridor at Lake Avenue and Fifth Avenue West.

LHB was hired to manage and design the project through all phases of project development and delivery beginning with a comprehensive topographic and boundary survey of the downtown corridor; preliminary design, public engagement, and project scoping; final design; and construction. LHB’s work included roadway design; utility design for new water main, gas mains, and sanitary services; drainage design for stormwater management, treatment, and conveyance; structural engineering design for foundations, retaining walls, building vault restoration, and bridge modifications; mechanical and pipeline engineering design for new steam systems; electrical engineering design for high voltage power distribution; architectural design for transit and building modifications; and land surveying services for topographic survey, utility locates, and construction staking. LHB also provided support landscape architecture services, including the creation of schematic design sketches and renderings, public engagement facilitation, public plaza design, and quality assurance for the overall streetscape design.

Project Type Street Reconstruction, Utility Replacement, Streetscape & Amenities

Location Duluth, MN

Completion Date October 2021

Features & Highlights 2022 ACEC/MN Engineering Excellence Grand Award Recipient

Markets Bridges & Structures, Roads & Highways, Power & Utility Infrastructure

Services Civil Engineering, Architecture, Landscape Architecture, Mechanical Engineering, Survey

LeftRight_1b_150714b — Public input balanced with community needs created a concept that prioritized access and traffic concerns.

Community Engagement

LHB led a multi-year public engagement process that provided over 10 formal public meetings as well as individual and group meetings with nearly every property owner, manager, and business on the project corridor. The entire process was informed and spearheaded by a stakeholder committee group that represented businesses, the community, planning, and advocacy groups.

LeftRight_2_150714a — The street’s narrow width added to the challenges of maintaining business access, providing pedestrian safety, and creating temporary utility services.

Traffic Control & Staging

Superior Street is a heavily used commercial business district and construction would be constrained within a narrow 80-foot right-of-way that was defined by the face of the buildings on each side of the street. The constrained site would severely limit the space available to accommodate the materials, work zones, and the public. Innovative and flexible planning and design to maintain access helped businesses and other downtown interests weather the construction period.

Aerial flyover of the completed project – October 2020

"LHB exceeded our expectations with their innovation. The trust and past relationships LHB had with the City, other agencies, the contractor, and the public, helped ensure a design that met all the diverse needs of the project and which we believe could not have been replicated by another firm."

Duncan Schwensohn, PE, Senior Engineer City of Duluth

"LHB showcased their professionalism and expertise through every phase of the Superior Street project. Not only did they design the project, they showed how much they cared about the outcome. We are fortunate to have such a talented firm headquartered in the heart of downtown Duluth."

Kristi Stokes, President Greater Downtown Council

Virtual Reality view of street utilities

3D Modeling & Virtual Reality

Keeping the public and businesses engaged was critical. LHB created a 3D model of all the utilities along the corridor to illustrate the various connections and layers that would be encountered during construction. LHB also created a virtual reality (VR) model that allowed users to “walk” the corridor at the street level.

Civil Engineering

Temporary Water

The deteriorating, 125-year-old, 16-inch, cast iron water main was replaced with 20-inch HDPE pipe, along with valves, hydrants, and services. High water pressures (125-psi) required the main to be constructed in stages. An entirely separate temporary water main system was installed to maintain service for the users.

Power & Utility Infrastructure

downtown intersection with historic buildings

Signature Project

The Superior Street Reconstruction was truly a “once in a lifetime” project for Duluth. This dramatically and positively re-shaped the vision for downtown Duluth and was a catalyst to sparking a community-wide conversation on the value of reliable, well-planned, public infrastructure, community values and needs, and the future of Duluth.

Landscape Architecture

Electrical Duct Bank

Minnesota Power and the City hired LHB to design a new, high-voltage electrical distribution concrete duct and vault system running the length of the street. The new, multi-cell duct bank system provides current and future power transmission capability and redundancy to minimize outages.

Electrical Engineering