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REASONS FOR VIBRATIONS FROM NIGHT-TIME MEDIAN SEWER
CONSTRUCTION:
Reasons for night time work:
The reasons for the sewer
being constructed at night are 1) due to the lack of room
available to construct the median sewer, and 2) the traffic
impact that daytime lane closures would create for local
traffic, tourist traffic and the delivery of good and services
to he Province of Ontario.
The median sewer construction
involves the use of a movable concrete barrier in the Toronto
bound direction. The movable concrete barrier is moved out at
night and the QEW is reduced to 1 lane from Bunting to Ontario
Street. With the movable barrier moved out the work zone
increases to allow for construction vehicles to safely enter and
exit the work zone as required.
Reasons for night time
vibrations:
The median sewer
from Ontario Street to Bunting varies in
size and depth. The sewer is as larger as 1.8m and as deep as
4.5m. Due to the limited width in the median area the sewer must
be constructed with trench boxes as sown below:
During the installation of the trench boxes it may be
necessary to force the boxes in place using a hydraulic
excavator. This may be why a loud "banging" noise is
heard during the night.
Once the sewer is installed, the trench must be backfilled
with gravel. Considering the depth of the trench, it is
necessary to compact the gravel in 300mm layers using vibratory
equipment. The vibrations from the compaction equipment may resonate
through the ground to the nearby homes. Efforts such as
increasing the thickness of the gravel layers and adding water
to the gravel have been made to reduce the compaction efforts,
which reduces the overall vibrations felt by nearby homes.
Considering that the sewer construction is a mobile operation
and that approximately 20m of pipe is installed in one night,
vibrations can last as long as 5 nights in your
area.
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