Calumet City’s DiPaolo Construction was awarded the
$14 million construction contract to install access manholes into two combined
sewer lines in the middle of busy intersections, while keeping at least one lane
of traffic moving in each direction for cars and CTA busses. Shoring the 18’x24’x24’
work trenches without over excavating, and without the vibrations attendant on
pile driving was a challenge, until submission of engineering notes and
calculations, three dimensional CAD drawings, and installation instructions to
the Department of Water Management convinced city officials that the proposed
slide rail “dig and push” trench shoring could do the job.
Once the 6 foot diameter sewer pipe was exposed in
the trench, DiPaolo created a flume using two 16” lines to maintain flow in the
sewer while the precast manhole was installed in the cut line. Once the first
manhole was installed and backfilled, the same dig and push equipment was used
to open the second cut and install the second manhole. DiPaolo executives
praised the dig and push trench supports, as approved by the City of Chicago,
for use in high traffic, close spaced trenching over existing sewer lines.
