together for the past 20 years throughout Eastern Canada out
of Corner Brook with a crew that now includes a first-year
apprentice and a welder.
The old bridge had been built on a fairly large concrete
mat, but not on piles, “and there may have been some settling.
I suspect not much concern was offered back then in the way
of supporting a small bridge such as this one,” said Tripp, but
since the late 1950s, technology and building standards have
changed. “Now soil borings can tell how close bedrock is,
what kind of material is below the bridge and whether piles
are required or not.”
In this case, there was quite a lot of soft ground below the
bridge and the geotechnical survey indicated dense silty sand
and gravel. He said, “The new build had to be done correctly –
and as we all know, there’s no beating a structure constructed
on properly driven pilings.”
Tripp Marine worked with David Zanchetta, sales and
field services representative for Berminghammer Foundation
Equipment of Hamilton, Ont., to determine the best equipment
for the job. Since dynamic monitoring had to achieve
a factored axial compressive resistance of 1,000 kilonewtons
(kN) ultimate limit state capacity on at least four of the 12
driven piles on each side of the abutment, Zanchetta recommended
Berminghammer’s BL26 box leads and its B21
hammer for the Cammies Brook project, noting that the B21
can provide about 1,000 to 1,600 kN ultimate limit strength.
“The B21 is 72 kilojoules kJ and the government had a
maximum rated pile hammer energy of 84 kilojoules,” said
Tripp. “We were driving a 12-inch 74-pound-foot H-pile and
we couldn’t exceed that rating. The next size hammer, the
B32, had 110 kJ.”
“Typically we’d recommend our Vertical Travel Leads on
cranes or Excavator-Mounted Leads for excavators,” said
Zanchetta. “They speed up the process of pile positioning and
are easy to manoeuvre, especially for battered piles. However,
it does take some time to put a system like that together, and
it is more costly than simple hanging box leads.”
However, if firms already have a crane that can handle
hanging box leads – one of the simplest of lead systems – that
can be a good, budget-wise solution, Zanchetta says, since
there is no connection to the boom tip or crane body, and the
leads are relatively easy to set up.
“And with just about a month’s time required to deliver –
and the lower budget due to the limited number of piles – it
made sense for Tripp to rent something that could do the job
relatively quickly; maybe not the quickest, but the most costeffective
for their needs,” Zanchetta said.
No fabrication required
Projects are going ahead, “but with extreme caution” in
Newfoundland and Labrador because of the COVID-19 pandemic
this summer, Tripp says. Travel restrictions between
Ontario and Newfoundland and Labrador meant that
Berminghammer was not able to send a technician to assist
with the rig-up as anyone sent from the company’s home
base in Hamilton would have to quarantine for two weeks.
“Instead, we held a virtual rig-up session with our technician
hosting. We’ve done a couple more since, but it was
the first time we did one that way,” said Zanchetta. “The
technician was very methodical about outlining the process
of putting the leads together and the operation of the
hammer, and Tripp was able to execute with excellent
production rates.”
“A system that has leads that attach to the boom tip offers
lots more control, but it’s quite a bit more work to marry that
lead system to a crane boom. The beauty of this system is that
there’s no fabrication required,” said Tripp. “The box leads
can be picked up by any crane and the swinging leads hang
free from the crane boom, so you just stand them up and go
to work.” Setting up and positioning each pile takes a bit more
work, “so if we had 150 piles to drive, or if there were a lot of
unforeseen subsurface obstructions, like rocks and boulders
that were giving us trouble, we’d have to go with a different
system. But this works great for smaller projects if the ground
conditions are consistent,” such as at this site, where the geotechnical
survey indicated dense silty sand and gravel.
CCS had built a temporary one-lane rock-fill bypass road
equipped with a stoplight 25 feet away from the site to redirect
traffic and free up the old bridge for demolition and
replacement by the new 60-foot-long span.
“The sheer tightness of the site was shocking – I’ve never
had such a compact jobsite before,” said Tripp, who has been
in the pile driving industry for more than three decades. “Not
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PROJECT SPOTLIGHT
38 Q3 2020 www.pilingcanada.ca
/www.pilingcanada.ca
