from 40 ft to 90 ft. Approximately 1,050 ft long, the bridge
supports the rail lines, the station terminal, and the platforms
for the METRO Blue and Green lines. Its design will facilitate
connections to two other light-rail lines planned for the future.
This level also includes tail, or storage, tracks having sufficient capacity to store six light-rail trains. The tail tracks
were constructed to stage as many cars as necessary to handle
the rush of spectators leaving Target Field at the conclusion
of a large event. Beginning at the west end of the bridge, the
tail tracks wrap around the south side of the HERC. Built on
grade, the tails required the construction of large retaining
walls, and because of poor soil conditions, these walls were
built on pilings. These same poor soils ruled out the use of
traditional fill in many locations within the retaining walls
because the sheer weight of the fill and the waiting trains
would have caused settling. As a result, the project team opted to use large geofoam blocks as a lightweight alternative, in
some areas stacking them to a height of 15 to 20 ft.
Located at street level, the second level is home to Station
Square and to a coffee shop and other planned businesses. The
square gives pedestrians and cyclists access to the sidewalks
and trails in the surrounding community. It is also home to a
massive outdoor amphitheater featuring a curved design and
a built-in cascading stairway that leads to the third level. Visitors entering Station Square from the street proceed past the
coffee shop and beneath the light-rail platforms and bridge
before entering the amphitheater and the cascading staircase.
The underside of the bridge also has programmable light-emitting diodes that illuminate the part of the square at the
foot of the amphitheater. The second level also includes the
upper portion of the two-level parking garage.
The first level, the bottommost, is belowground and in-
cludes the Northstar Commuter Rail station and the lower
portion of the parking garage. The garage offers the flexibili-
ty to add spaces to support future development. The platform
here takes Northstar Commuter Rail passengers to the north-
ern suburb of Big Lake, nearly 45 mi outside of Minneapolis.
The station on the third level serves two light-rail lines.
One platform there is for the METRO Blue Line, which connects passengers to Minneapolis–St. Paul International Airport and the Mall of America, south of downtown Minneapolis. A second platform serves the METRO Green Line,
which takes passengers east to downtown St. Paul, Minnesota’s capital.
As light-rail lines are added to the system, Target Field
Station can be expanded to offer additional platforms. In fact,
the station is designed to accommodate several planned lines,
including the 16 mi long Southwest line and the 13 mi long
Bottineau line. Scheduled for completion in 2019, the Southwest line will stop at Target Field Station and serve the southwest Minneapolis suburbs of St. Louis Park, Hopkins, Minnetonka, and Eden Prairie. Scheduled for completion in 2021,
the Bottineau line will serve Target Field Station and feature
stops in the northwest Minneapolis suburbs of Golden Valley, Robbinsdale, Crystal, and Brooklyn Park. By accounting
for these upcoming needs, the design of Target Field Station
is expected to reduce the construction costs associated with
the new lines by tens of millions of dollars and ensure that the
station will continue to serve as a major mass transit hub and
community gathering space well into the future.
Certain site considerations led the design team to develop
an innovative system for collecting and reusing stormwater.
For example, the presence of petroleum-based contamination in various places precluded the possibility of allowing
stormwater to infiltrate into the ground. With the Mississippi River only about 1 mi downstream of the project site,
the design team sought to prevent any movement of existing
contamination plumes in the area that drains to the waterway. This and other challenges complicated efforts to meet
the stormwater management requirements specified by the
THE PROJECT TEAM opted to use lArge geofoAm BloCks As A lightweight
AlterNAtive, iN some AreAs stACkiNg them to A height of 15 to 20 ft.
With its unique trilevel design, Target Field Station
includes a cascading staircase linking the top two levels
and a parking garage that is split between the lower two levels.
 Civil Engineering november 2015