This bridge is the southernmost of two bridges in the causeway that
make up the Minnesota state highway MN-119 crossing over the Minnesota
River. MN-119 is located at the northern extent of Lac Qui Parle, the
lake that backs up behind the Lac Qui Parle Dam. This particular bridge
crosses the historic Minnesota River main channel.
The bridge has a very simple design that can be quickly erected. The
process starts by using a pile driver to pound in 4 rows of steel
tubes. The row of tubes on each end of the crossing is used to support
the abutments, which are made from ready-mix concrete. The two rows of
tubes in the middle of the river are cut off and a concrete box is
built around the top of the tubes. From here, steel beams are placed
from the abutments to the piers, and between the piers. A plywood
form is built between the beams, and the bridge deck is poured. Once
the deck is cured enough to support equipment, the guardrails are formed
and poured. The abutments are backfilled, metal guardrails are installed,
and some landscaping finishes off the project. An experienced crew can
install a bridge in this manner in as little as 8 weeks.
The photo above is a view of the south bridge span over the Minnesota River
as seen while traveling southbound on highway MN-119 towards Dawson.
The photo above is the downriver southeast face of the main channel span. The
photo below is looking northeast down the southeast face of the bridge.
The photo above is looking northeast down the length of the bridge deck from
the southeast corner of the structure. The photo below is the bridge plate.
These two photos show an old bridge pier sitting just upstream from the
current river crossing. I have not been able to determine exactly what this
pier is. It might be from the river crossing that was replaced when the
current 1977 bridges were built. The second possibility is that this was part
of the pre-1940 river crossing that was flooded when the Lac Qui Parle Dam was
completed. The final possibility is that this is part of an old railroad
bridge, possibly the BNSF Watertown Subdivision line that was flooded out in
1940 and moved to a new alignment.