PROJECT SUMMARY:
Due to a design change a previously built 30 foot retaining
wall needed to have its height supplemented by another 20 feet
near the DeBaliviere Station.
PROJECT SOLUTION:
The key to solving this problem was an old-school gabion wall,
or essentially metal baskets filled with rock. The wall
was relatively easy to construct and would go up quickly.
However, building on top of the existing CIP (cast in place)
wall presented unique design and construction challenges.
SPECIAL CONSIDERATIONS:
Because the CIP wall had already been built and its load
bearing capacity factored into its construction, this new 20
foot wall with a large footprint had to be light weight and use light weight
backfill. A special material called "popcorn rock" was
hauled in from Kansas City specifically for the project.
Popcorn rock is much like volcanic rock but is a cellular fly
ash filled with many hollow air pockets.
This makes the rock light weight enough for many applications
and in this case allowed weight from the wall backfill to be
distributed over a greater footprint.
PROJECT RECORD:
The supplemental wall
built of gabion baskets was built on top of the existing
CIP wall.
Looking down on the
existing Metrolink line. This view is from above
the CIP wall.
Ideal workers inspect
the footing where the gabion baskets will eventually be
placed.
Ideal workers filling the gabion baskets will eventually be
placed.
Ideal crew members
work to check the gabion baskets A close-up view of a
load of backfill being delivered to the site.
A view between the
supplemental gabion baskets and the new CIP under
construction behind it.
This temporary
shoring will be buried in place.
A view showing how
much wider the gabion wall had to be in order to disperse
the load over a greater area.
A view of the
half-completed wall extension prior to completion of the CIP
wall behind it.
