“This was to ensure all water works were completed to
meet the environmental regulations regarding the provincial
fish spawning restrictions/regulations and the river’s poten-tial
flood times,” said Brian Horner, MasTec’s piling general
manager. “In mid-June, the project will recommence and
allow for the remaining cofferdam and H-pile installations.”
MasTec’s involvement in this $10 million project includes
designing the temporary cofferdams ( four-sided steel sheet
pile box) required for this job.
“There were 14 cofferdams in total,” said Horner. “Eight
were to be designed for placement into the Assiniboine River,
and six were designed for placement into the shore lines
of this river. We had to design with the water force/move-ment/
flow of the Assiniboine River in mind, as well as the
hydrostatic pressure of this river. The provided geotechnical
reports – along with hydrologic and hydraulic reports – also
had to be taken into consideration.”
The design of the cofferdam utilized the AZ39-700 sheet
piles that MasTec Canada currently owns. These thick-walled
sheet piles can withstand the lateral ground pressures and
the hydrostatic water pressures applied to these sheet piles/
cofferdams. The design also utilized a whaler frame that
consisted of HP250x85 beams, which were installed at the
ground level.
“This allowed for the proper alignment of each sheet to
ensure the sheets were installed at the design location,”
he said. “Afterwards, the installed sheet piles were then
welded to these beams. This locked in, ensuring strength
and support.”
Additionally, the team had to utilize trestle beams in order
to attain better access to the cofferdam locations in the river.
PROJECT SPOTLIGHT
“Working during the coldest part
of the prairie winter (January
and February), a night shift was
utilized to ensure the aggressive
contract schedule was met.”
– Brian Horner, MasTec
These beams were designed in conjunction with the coffer-dam.
MasTec then installed additional reinforcement pipe
piles, which supported these trestle’s beams.
“We installed the welded whaler beams at the ground
level,” said Horner. “These beams acted as an alignment and
guidance for the installation of the sheet piles as per the
design requirement. After the sheets were installed, they
were then welded to the whaler beams.”
Following the excavations of the cofferdams – completed
by the client – MasTec installed the H-piles required to sup-port
the concrete piers, each of which was up to 47 metres
long. The team welded driving shoes to each pile prior to
installation. Each pile had to be welded/spliced together in
order to achieve the design lengths. After the completion
of the concrete works by the client, MasTec removed the
sheet piles.
“All of this work was achieved utilizing our well-maintained
equipment to support the piling’s activities,”
MasTec Canada’s nightshift crew installing
the sheet pile cofferdam with the ICE
vibro and Terex 110T Crawler Crane
PILING CANADA 49