Flatiron Construction. Piling operations began in October of
2015 and the work was completed in July 2016.
Allan Bowers is operations manager for BAUER
Foundations Canada. Bowers oversaw his company’s involvement
in the new Champlain Bridge project and says the client
was very happy with the job performed by BAUER.
“Our element of the work went exactly as planned,” he
said, “This is something that hopefully we can continue to
excel in as we engage in these large-scale, complicated projects
around the world.”
BAUER Foundations Canada initially mobilized two
drilling rigs for the Champlain Bridge job – a BAUER BG 28
and a BG 40 – to install the piles. The original BG 40 on site
was later replaced by a new BAUER Premium Line BG 39 in
January 2016.
A total of 200 rotary bored piles were installed, with 190
piles drilled from land or jetties. The remainder were marine
piles drilled from barges. The piles had diameters of 1,300 and
2,000 millimetres and ranged in length from 10 to 24 metres.
Project challenges
According to Bowers, there weren’t any issues involving safety,
the environment and quality, but a number of challenges did
arise with the piling work that needed to be dealt with.
Working from a floating barge in the middle of the St.
Lawrence River to install the 2,000-millimetre concrete piles,
for example, proved one of the more challenging aspects of the
project, Bowers says, and it required detailed planning and coordination
with the client and other crews on the job site.
A number of special measures were required to pull this off,
including changing the geometry of the barges to allow for safe
and efficient drilling. The stability of the barges was also carefully
checked for all conceivable construction scenarios and
contingencies, with adjustments made if necessary.
As concrete needed to be pumped in from onshore facilities
during the marine pile construction, it was also necessary
to adjust the concrete mix to account for the long pumping
lines that were required during this process.
Bowers says three barges were utilized during the piling
portion of the project, “a crane barge, a drill barge and a service
barge to take the equipment out to us.”
He adds the depth of the water where the piling crews were
working in the St. Lawrence River was fairly shallow. “This
meant that maneuvering the barges had to be done a certain
way, and that presented some challenges,” Bowers said.
Companies involved in the new Champlain Bridge project
were required to comply with rigorous environmental monitoring
and mitigation measures to protect the surrounding
natural environment.
One of the measures employed by BAUER Foundations
Canada was using vegetable oil rather than hydraulic oil in
the company’s equipment on site to lessen the environmental
impact if a spill did occur.
“We were in some cases working on the river, so there was
a huge emphasis on avoiding any issues there,” Bowers said.
BAUER Foundations Canada, which had 20 people working
on the job site at peak of construction, started the project
with two crews on a day shift. The company added a third
night shift crew during November and December of 2015 to
meet the client’s schedule.
Bowers says one unique aspect of the new Champlain
Bridge project involved ground conditions. In addition to
bedrock, the BAUER piling crews encountered a variety of
underlying soils ranging from sand, silt and shale. They also
came across glacial till, with hard intrusive igneous dykes
and sills running through some of the till layers.
“The rock strength was quite variable, and it was quite strong
in some places, but there weren’t any major issues,” said Bowers.
According to Bowers, strict criteria were implemented for
cleaning the base of each pile bore before it was installed. For
example, the thickness of sediment or loose, disturbed material
covering the pile toe could not exceed 15 millimetres and
airlifting was carried out to remove debris for the pile bores.
This was followed by camera inspection before the concrete
was finally pumped in.
Bowers says all of the piles on the new Champlain Bridge
project underwent quality control testing using either thermal
integrity profiling or crosshole sonic logging, which
verifies the structural integrity of drilled shafts.
PROJECT SPOTLIGHT
“Our element of the work went exactly
as planned. This is something that
hopefully we can continue to excel
in as we engage in these large-scale,
complicated projects around the world.”
– Allan Bowers
60 Q4 2018 www.pilingcanada.ca
/www.pilingcanada.ca
