Ontario is the only Canadian province with occupational
health and safety legislation specifically relating to working
platforms for rotary foundation drill rigs. Specifically, the
legislation requires that before a drilling operation begins,
a professional engineer must “design a supporting surface
for the drill rig in accordance with good engineering
practice to adequately support the drill rig during all
drilling and drill rig set-up activities.” Further, the professional
engineer must designate and design the path on which the
drill rig will travel to and from the active construction site.
To review the current legislation, refer to sections 156.1
to 156.9 of the Ontario Health and Safety Act pertaining to
construction projects – download the document by visiting
www.ontario.ca/laws/regulation/910213.
A collective focus
“Part of the increased attention to working platforms has
to do with the great outreach that the different organizations
have been doing regarding working platforms,” said Martin
Taube, P.Eng., P.G., vice president of business development
with Menard USA. “But it’s certainly not that it’s more of an
issue now, it’s just that it’s being discussed more. Working
platforms have been an issue for a very long time.”
In 2018, ADSC-IAFD, the Deep Foundations Institute
(DFI) and the Pile Driving Contractors Association (PDCA)
came together and published a deep foundation industry
consensus position on working platforms for foundation
construction and related equipment in North America. In
the consensus document, the organizations outlined that
they will support the general guidelines used in the U.K.,
spearheaded in the early 2000s by the Federation of Piling
Specialists (FPS), the piling association in the U.K.
“The consensus document was a big step forward, in my
eyes, in an agreement and understanding on this side of the
Atlantic that working platform safety is something that we
as an industry need to lead and need to do,” said Finbow. “The
sad part is that often, safety legislation is written in blood.
That’s what gets authorities to change. But now, we’re getting
a lot of support in the industry to drive this through and prevent
future accidents.”
“It’s organizations like ADSC-IAFD, DFI and PDCA that
are very important in bringing together people from all over
the country so that we can get some sort of consensus view
on how to deal with issues,” said Gildea. “Everyone appreciates
that working platform safety is a concern, but nobody, until
the last couple of years, has stepped up as a collective group
rather than analyzing the problem on a micro-basis.”
Working platforms – what are they?
Essentially, the working platform is the part of the construction
site above the natural subgrade on which a rig is placed and
that holds the rig level in order to start its foundation
construction activity. The working platform is what prevents
these large pieces of machinery from tipping over and causing
catastrophic damage. The scope of the consensus position from
ADSC-IAFD, DFI and PDCA is focused on ground-supported
working platforms and includes not only the platform itself,
but also its associated ramps/roads and access points.
“The working platform is the natural or human-made
ground surface or subgrade capable of safely supporting
construction equipment,” said Timothy Siegel, P.Eng., G.E., D.GE,
a senior principal engineer with Dan Brown and Associates.
Anywhere that a rig is driving or working from must be able
to support the weight of the equipment and any bearing pressures
during construction activity.
“You also need a safe area to assemble the equipment –
we call that a laydown area,” said Taube. “And then from the
laydown area, ramps or access roads to the actual site where
the work will be performed requires an adequate platform.”
“The platform must safely support any type of tracked
equipment – whether it be a crawler crane, a piling rig or
whatever it may be – under all loading conditions,” said
Gildea. “And the way we look at this is under extreme loading
conditions; we’re looking at the worst case here because the
platform needs to be fully stable under all potential loading
conditions for these rigs so that there is no possibility that it
can collapse and the rig topple over.”
The duty of the platform is to provide a stable, safe
environment for piling contractors and other construction
trades to work on, day in and day out.
The concerns
According to Terry Bolsher, former chairman of FPS,
approximately one-third of all accidents in the piling industry
result from defects in working platforms.
DFI conducted a survey of its membership in 2017 about
experiences with working platforms. The results highlighted
the significance of the problem. Eighty-eight per cent of
respondents to the survey indicated that inadequate working
surfaces caused safety issues for their company, and 98 per
cent said that it caused operational issues for their company.
Even more alarming, 68 per cent admitted that their company
had tipped a large piece of equipment due to inadequate
working surfaces.
“These results weren’t surprising,” said Taube, who along
with Matthew Meyer, principal at Langan Engineering and
Environmental Services, assisted DFI in creating the survey
questions and gave a presentation on the results during DFI’s
SuperPile ’17 Conference. “You can see that it’s a huge issue.”
Inadequate working platforms have myriad issues that
result in safety concerns.
“The most common hazard is soft soil that is too weak to
support the construction equipment,” said Siegel. “The soft
ground can deform or experience a shear failure beneath
construction equipment and result in overturning.”
Gildea agrees, adding that soft ground in the upper three
metres of a site’s ground profile is a major site issue.
“If the rig is on a platform sitting on top of soft grade, that’s
a recipe for disaster,” he said.
In addition to soft soil, steep slopes can result in failure, as
can inadequately constructed ramps or platforms that do not
have enough coverage over a site. Uneven terrain, ineffectively
backfilled utility trenches and poor site drainage can also be
causes for concern.
The size of the working platform can be a potential
problem, too.
FEATURE
CONTINUED ON PAGE 38
36 Q3 2019 www.pilingcanada.ca
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