Wabasha Street Bridge Project Information

April,1996------------------------------------July,1998----------------------------------Fall,2001
Construction Begins------------------------Open to Traffic----------------------Stair Towers Complete

Fun Facts F A C T O I D S about the Wabasha Bridge

AWARDS

	Federal Highway Administration, Washinton DC 1998 Excellence in Highway Design Award, Merit Award
	Consulting Engineers Council of Minnesota 2001 Grand Award
	Minnesota Society of Professional Engineers 2001 Seven Wonders of Engineering in Minnesota
	American Concrete Institute, MN/IA Chapter 1999 Excellence in Concrete Construction Award
	American Consulting Engineers Council 2001 National Finalist, Engineering Excellence Award
	Minnesota Concrete & Masonry Association 1999 Honor Award
	Florida Institute of Consulting Engineers 2001 Engineering Excellence Grand Award

Featured in the following publications:
Architecture Magazine
Smithsonian Magazine
Engineering News Record
Civil Engineering Magazine
CRSI Great Bridges 1990 - 2000
Concrete Construction Magazine
Concrete Producer Magazine
St. Paul Pioneer Press newspaper
Minneapolis Star and Tribune

The new Wabasha Street Bridge will actually be two separate parallel bridges, one for the north
bound and one for southbound traffic. It will be a concrete segmental box girder bridge, which is a relatively
unique structure type. The bridge deck is supported underneath by two sloping side walls that
are joined together on the bottom with a slab to form a closed box. This concrete box acts as a
beam to span between the piers.

One advantage of this type of bridge is that it can be built without any false work, so that
construction can proceed over the Mississippi River, Shepard Road and the railroad tracks
without disrupting activities below. This is done by building the bridge in 16 foot long increments,
called "segments." starting at the piers and cantilevering out on both sides simultaneously.

Concrete for the segments is cast in forms supported by the previous segment, Once the concrete
cures, the forms are moved further out from the pier for the next segment. Each segment is
attached to the bridge by high strength steel tendons that are stretched and then anchored to compress the concrete.
The cantilevers extending from a pier make the shape of a "T", with the top of the "T" getting longe
r with each segment cast. When cantilever tips from two adjacent piers reach almost 200 feet out, only a small
gap is left near the center of a span. That gap is then closed with one last concrete section to complete
the span.

By the mid-1850's, Saint Paul, as a settlement, was a thriving fur trading center in what is now the
downtown. At that time, Saint Paul was the prime port on the upper Mississippi River, connecting the
Minnesota territory to the rest of the country.

The settlement was also undergoing a population boom. In 1849, the population of Saint Paul was 900
residents. By 1860, the population had grown to over 10,000 residents. Besides settling inland from the
east banks of the river, people also settled on the west side of the river bank. Through much of the
1850s, the west side residents relied on a ferry to carry them to the east banks of the Mississippi River
and the center of commerce in the small but growing town of Saint Paul.

Because of the overwhelming demand on the crossing, the Minnesota Territorial Legislature
incorporated the Saint Paul Bridge Company in 1854 to build a bridge to replace the ferry crossing.
The Legislature also incorporated the City of Saint Paul on the same day in 1854. The City completed
the new bridge at Wabasha Street in 1859. Officially named the Saint Paul Bridge, it was a wooden
Howe Truss, a state-of-the-art design.

A second Howe Truss bridge was followed by an all-iron Pratt Truss in an innovative version
known as a Whipple double-intersection Pratt. These designs were all through trusses, rising
above the roadway to provide navigation clearance below. Vehicles passed through the truss
structure.

The present Wabasha Street Bridge is the fourth bridge to be constructed at this river crossing.
Originally built in 1889, it is an iron cantilever deck-truss, an advanced design for its time.
The south spans were rebuilt a decade later. Because of its significant engineering and the fact
that it is the only surviving cantilever truss bridge in Minnesota, the National Park Service listed
the bridge in the National Register of Historic Places in 1989.

Because of its age and increasing maintenance and repair problems, city engineers initiated
studies in the late 1980s to assess the bridge's structural condition. It was determined that the
bridge has a limited useful life because of its deteriorating structural condition. With significant
repairs and restricted load limits, the bridge remained open and plans for replacement were started
immediately. In 1996, after many years of planning, a new Wabasha Street Bridge will be
constructed. Not only will the new bridge accommodate the predicted demands of vehicle,
pedestrian, and bicycle traffic of the future, but serve as a significant addition and vital direct
connection to Saint Paul's Riverfront attractions.

HAER Report - Historical Architectural and Engineering Record. National Park Service, Dept of Interior

Construction Schedule

Estimated Construction Cost

Conceptual Design Features

This design is relatively unique to Minnesota. The bridge will consist of three spans with piers located at
the river's edge adjacent to Shepard Road, on the north bank of Raspberry Island, and in the south river
channel. The segmental concrete box girder design offers a shallow curved profile between the pier
supports. The bridge will be constructed of a series of cast-in-place concrete segments starting from the
center pier at Raspberry Island.

Principal features of the bridge structure include a curved alignment and split roadways. The curved
alignment allows the bridge to continue the grid of Wabasha Street on the north bank and then return to
the correct alignment with Wabasha Street at the south bank. Unlike the present bridge which curves at
the bluff, the new design places the curve at the bridge's mid-point over Raspberry Island.

The bridge deck is split in the middle essentially providing separate bridges for north bound and south
bound traffic. The roadway portion provides two 12 foot wide lanes and a six foot shoulder/bicycle
lane, adjacent to a low traffic barrier separating roadway traffic from any pedestrians on the 12 foot
sidewalks.

The amenities package for the bridge includes ornamental railings and lighting, stairways, plazas and park
areas.
Artist renderings of the bridge

Pedestrian-oriented environment

The design includes sidewalks that are 11'-4" wide and other amenities that will attract people to the
bridge and make crossing the bridge a more pleasurable experience. The railing design, lighting, and
bridgehead elements (which mark the bridge ends) and a patterned concrete walk define the bridge as
a distinct place of crossing the river.

Six overlook areas are placed at the three pier locations and defined by ornamental grillwork.

The overlooks at the center piers have major emphasis as they include stairs down to Raspberry Island.

Color scheme draws upon the Saint Paul's palette.

The bridge structure will be tinted a soft buff color (sandstone yellow) - a color that is reflective of the
main body of buildings in the city and the river bluff. Terracotta (earth brown) and patina green
(weathered copper) are used as accent colors. Terracotta roofs are prevalent horizontal colors in Saint
Paul. This color will be used as the principal railing color. The dome of the Saint Paul Cathedral and
spires of other area landmarks demonstrate the use of patina green as a highlight color. The ornamental
metal grillwork at the overlooks will be colored patina green to add this special emphasis to these areas
of the bridge.

At night, the bridge will have a special image.

Roadway and pedestrian walk lighting will be provided by a series of ornamental light standards on the
bridge deck. Aesthetic illumination will be integrated within the grillwork on the overlooks. The bridge
structure, both box and pier will also be lit to give a presence at night. Three pairs of searchlights will
accompany the bridge to signal special events in Saint Paul. A pair at the center pier will shine straight up
into the sky. Pairs at both ends of the bridge will be aimed at the center to form an inverted "V" over the
bridge.

Special attention was given to making the landing environments compatible with the urban character of
the north bank of the river and the park area of the south bank. The north landing will be merged with a
remodeled Ramsey County Jail plaza and feature additional areas with overlooks to the river valley. The
character of the north plaza will follow the design of Kellogg Mall Park. The south plaza areas are
designed to reflect the park-like environment of the south bank and will complement the adjacent Flood
Wall esplanade to the east. Circular plazas at each side of the bridge provide overlook areas to the
river, as well as stairs and handicapped ramps to the river bank promenade level.

A new Raspberry Island bridge to the west side of the Wabasha Street Bridge will provide vehicle and
pedestrian access to the island from the south bank. This bridge provides an alternative to the stairways
for persons with disabilities to access the island.