The New Winona Bridge – Minnesota / Wisconsin

This $78M segmental bridge provides mobility between Minnesota and Wisconsin over the Mississippi River with a 2,300’ context-sensitive concrete segmental bridge alongside a historic bridge. It currently provides one-lane of vehicular traffic in each direction, as the existing bridge is being rehabilitated. Once that is complete, the new bridge will have two southbound lanes and a pedestrian path and the existing bridge will have two northbound lanes, adding needed capacity. This bridge was Minnesota’s first to be delivered with the Construction Manager/General Contractor (CM/GC) method. The team used concrete segmental construction, and leveraged CM/GC to achieve a 15-month time savings, $18M cost savings, value-added aesthetics, and meet the needs of the river community.

The bridge was designed for easy access for inspections, maintenance and utilities. With an integral wearing surface, stainless steel reinforcing bar in the deck, bidirectional post-tensioning, high strength-concrete, and the fewest possible joints and bearings, it has exceptionally low life-cycle costs and a design life of over 100 years.

Acceleration of the project was necessary – the original, adjacent bridge was closed for gusset plate repair, resulting in a 65-mile detour that impacted emergency responders, commuters, and the local economy. From each of the two pier tables, construction proceeded in two directions at once for a total of four simultaneous operations.

Its 7,000 psi concrete mix design resulted in a high-performance, low permeability concrete and curing temperatures were closely monitored through all construction seasons.

Innovation of Design and/or Construction

Minnesota DOT is a leader in technical innovation and project delivery. Minnesota DOT utilized CM/GC for its first time on this project. A concrete segmental bridge design, allowed work to progress simultaneously under multiple work packages. Overlapping segmental construction and design eliminated 15 months from the project schedule. The following innovative items were incorporated:

Eco-friendly wintertime work over the river that resulted in the team developing a wintertime best practices manual for working in the river which will be used by MnDOT for years to come.
The use of stainless steel reinforcing bar in the bridge decks. MnDOT continues to lead the industry in the development of specifications and details for the use of stainless steel reinforcing.
Polypropylene duct for post-tensioning tendons. Galvanized and epoxy coated anchors were specified based on location to maximize durability.
The use of post-tensioning tendon grout meeting the latest PTI specifications including current interims that do not permit the use of inert filler.
Research, specifications, and in-place performance testing of innovative thin premixed polymer concrete deck overlay at discrete locations such as where temporary access holes were used during construction.
Lower tensile stress limits than required by AASHTO.
Requirement for long-term bi-directional compression across temporary construction access hatches in the deck.
Finite element moment curvature analysis to determine refined substructure stiffness in lieu of AASHTO approximate methods.
Site-specific thermal analysis representative of the local conditions in Minnesota.
Force-pulse (statnamic) dynamic load testing of large diameter steel pipe piles to more accurately determine pile capacity and allow higher resistance factors reducing the number of piles required.
100-year service life for enhanced durability and low maintenance.

Rapid Construction

MnDOT’s project goal of completing the new Winona Bridge over the Mississippi River as expeditiously as possible was accomplished with a concrete segmental bridge, multi-directional construction, and overlapping design and construction through CM/GC. Traffic was maintained on the historic Winona Bridge while constructing the new bridge. Once the new bridge was complete, one lane of northbound, one lane of southbound traffic, and a pedestrian path was moved onto the new bridge while rehabilitation on the historic bridge is underway.

The concrete segmental design facilitates rapid construction of the superstructure. From each of the two pier tables, construction proceeded in two directions at once for a total of four simultaneous operations. Despite the cold Minnesota winters, the rapid segmental construction methods allowed the project to be completed over two months ahead of schedule.

Cost competitiveness of the Winona Bridge Project was significantly enhanced through the CM/GC process. The team provided MnDOT with over $18M in cost savings through innovative construction practices and project resource optimization.

The CM/GC approach, allowed optimization of the design, improved quality, reduced risk, and cost management as the project moved through final design to construction.

Aesthetics and/or Harmony with the Environment

The location of the bridge, in downtown Winona, offers multiple grand views of the bridge framed by downtown, the river, and Latsch Island. The long, graceful spans are supported by piers which visually blend into the superstructure with main span quad wall piers composed of slender shapes with maximum openness. Energy-efficient LED lighting accentuates the main channel piers and reflects in the water in the evening hours. The lighting system is programmable and has a marine radio control system that allows river pilots the ability to temporarily turn off the aesthetic lighting when navigating under the bridge during the night.

The light buff color chosen for the bridge was meant to work with the historic bridge concrete colors and complement the downtown native stone colors. The north and south abutments contain textured concrete finishes that provide visual forms like the organic tree movements on Latsch Island.

Views from the bridge were considered a high priority by the river community. Thus, an open pedestrian railing inspired by surrounding area elements was chosen along the west edge for the full structure length so pedestrians can enjoy open vistas of the surrounding landscape while crossing over the bridge. The east edge barrier is composed of solid concrete.

Minimization of Construction Impact on the Traveling Public

The new post-tensioned concrete segmental bridge was built from above with form travelers using the balanced cantilever method of construction to protect the environment, maintain river mobility, and allow rapid construction in all weather conditions.

The New Winona Bridge is made of concrete from its very own city of Winona. This reduced delivery distances, minimized emissions from delivery vehicles, and bolstered the local economy.

Opening the new bridge put an end to a 65-mile detour that affected emergency responders, commuters, and the local economy when the historic bridge needed to be temporarily closed for repairs.

Jury Comments

This project demonstrated how combining concrete segmental bridge design with innovative project delivery can result in reduced construction costs and time without sacrificing bridge quality and aesthetics. The bridge has a graceful haunched superstructure with elegant twin wall piers and aesthetic scenic lookouts. An amazing feat of engineering considering the winter construction. Nice form and function with overlooks that blend with the environment.