The Big M is a suspension bridge on the campus of the University of
Minnesota. It spans a trench that carries several railroad tracks.
The bridge connects two residence halls to the rest of the Minneapolis
campus, but is also used as a regional bicycle trail and for students
commuting to the University.
The bridge was built in 1949 about 4 blocks to the north east. It crossed
these same railroad tracks, but connected the Bierman Field athletic
complex to the rest of the campus. At that time, the bridge featured
flights of steps on each end due to the bridge being built higher over
the railroad tracks. New construction at Bierman Field and the relocation
of 5th Street SE required that the bridge be removed in 1995. Rather
than scrapping the bridge, it was moved to to its current location near
the intersection of 13th Avenue SE and University Avenue.
The bridge moving project required the construction of new abutments,
modification of the towers, and the installation of new suspension cable
anchors. The bridge deck was also strengthened and new safer railings were
installed. In its new location, the bridge is at ground level, so there
are no steps. This makes it possible for bicycles to use the bridge.
A key feature of the bridge is the large letter ‘M’ embedded
in the tower structure. The bridge towers are painted in the University
of Minnesota school colors of Maroon and Gold. The bridge deck is built
from wooden planks, resulting in a slightly rough and noisy ride when
crossing on a bicycle. The cables have some give, which results in the
bridge being very bouncy. Simply walking across the span is enough to
make the deck rise and fall an inch or more.
The Big M was given a routine inspection in early 2008. Inspectors were
alarmed at the level of deterioration that they found, and closed the
bridge on February 28, 2008. The bridge was closed several months while
it was sandblasted, repaired, and additional strengthening plates were
welded onto the structure. It reopened later in the summer of 2008.
The photo above is a view of the west face of the Big M bridge. The
building in the background is a private student housing complex. The
photo below is a photograph on a historical display located near the
bridge. It shows the Big M bridge in its former location prior to its
1995 relocation.
The photo above is looking east towards the Big M Bridge along the BNSF
railroad tracks that run through Dinkytown. The tracks once led to the Stone
Arch Bridge, but they now stop at the new Interstate highway I-35W bridge.
This right-of-way will be used in the future to construct Granary Road to fill
in a missing segment of the Minneapolis parkway system. The photo below is
a view of the south end of the bridge looking to the north across the
trench containing the BNSF tracks.
These two photos are views from the southeast corner of the structure.
The building on the far side of the railroad right-of-way is Roy
Wilkins Hall, a dormitory for University of Minnesota students.
The photo above is looking down the length of the pedestrian deck
from the south end of the structure. The photo below is a similar
view from mid-span.
These two photos are side views of the bridge span. The photo above
is the east side of the bridge, while the photo below is the west
side of the bridge. The triangular braces on the side of the structure
were added in 1995 in a project to strengthen the side railings and
make the railings conform to modern safety standards.
The photo above is the bridge plate. The designer, Joseph Wise, was a
professor who taught aeronautical and civil engineering at the University.
The photo below is a detail view of the suspension cable and the connection
to one of the vertical suspension rods. There are two parallel cables on
each side of the bridge.
These two photos are detail views of the anchor block at the southeast corner
of the structure. There are two steel bars embedded in the concrete. Eye
bolts are attached to these bars with pins. The eyebolts have a connector
that attaches to the suspension cables. Nuts on the eyebolts can be adjusted
to tighten the cable over time.
These two photos are views of the south end of the Big M Bridge on a sunny
morning in early summer of 2011. The photo above is looking to the northwest
while the photo below is looking down the length of the bridge deck.