Piedmont
Road at Miami Circle was undermined when a utility contractor cut a water
main, gas line, and sewer line. The high pressure flow of water
allowed soils and base to be washed out from underneath the concrete slabs
that made up the road.
The area affected was approximately 500'
long on both sides of the road. The road is a high volume road in
the Buckhead community. This was a high profile job due to the traffic and
location of the problem. The media was very active in reporting the
day to day progress.
The road was temporarily shut down
because of the lack of integrity and the safety hazards it presented.
Gibson's was called in to place a specially designed grout mix that we
have used in the past on similar projects. We had two crews that
worked around the clock on staggered shifts because time was of the
essence. Gibson's employed the use of ground penetrating radar as
well exploratory drilling to ensure that all voids were located.
After Gibson's specialists had a general
idea of the extent and location of the void the road was cored at
strategic locations and a high strength grout was pumped under the
concrete slabs. Over 150 cubic yards was pumped into the voids to
regain the structural integrity. The south bound lane was completed
first to allow some traffic flow, then came work on the north bound lane.
After the road was opened completely
the GA D.O.T. employed Gibson's to low pressure grout the side walks and a
parking lot adjacent to the road to ensure that there would be no future
problems here.
Because Gibson's made special
arrangements to mobilize immediately and because the tactics employed by
Gibson's Pressure Grouting the structural integrity of the road was
replaced and the road was opened in a fraction of time and a fraction of
the cost of removing the undercut areas placing engineered fill and base
and then replacing the concrete slabs.
Top Right - Area affect is one of the
busiest sections of road in Atlanta.
Middle Right - The entire road is closed
for time due to the instability of the undermined road and the need for
access by heavy equipment.
Bottom
