CC Jul-Aug 2021

TECHNOLOGY focus
A bridge into the future
Dan Vogen of Bentley Systems explains how Bentley's AssetWise, digital twins, and Microsoft's
HoloLens are being used to create immersive inspections of bridges to plan maintenance,
repairs, or replacement. David Chadwick reports
We've been building bridges ever
since the wheel was invented,
and a method for crossing over
a rocky-bedded river ford was needed.
The earliest bridges might have been
timber contrivances, but these were
soon replaced by sturdier stone
artefacts, cemented together by early
lime and mortar, some of which are still
standing today.
Those structures, of course, were
massively over-engineered by modern
standards, and the loads they had to
carry are a mere fraction of those borne
today. But even they are subject to
natural decay over time. An evolving
infrastructure has caused many older
bridges to be bypassed, which has led
to them being dismantled.
Modern bridge building, spanning the
last couple of hundred years, uses a
wider range of technologies, each of
which is subject to its own particular
form of decay. They are also
constructed to satisfy different criteria,
such as cost, strength, location, and
design elegance - the latter always
seeking a balance between the
lightness of a structure and its strength.
We are not unfamiliar, therefore, with
the problems that beset each type of
bridge, and the resources that are
needed to both detect problems and to
rectify them. The problem, though, is
that there are many thousands of
bridges that need to be maintained both
here and in the United States. The scale
of the problem is exacerbated by the
fact that maintenance schedules can
only be established by noting the scale
of a particular problem and the rate of
its decline through a series of repeated
visits. We are not only concerned with
legacy bridges, either, as every bridge
that has been designed, analysed, and
constructed requires a schedule of
asset inspections to ensure they
continue to operate at their designed
performance level.
BENTLEY WORK FEATURED AT
MICROSOFT IGNITE
Dan Vogen, vice president of road and
rail asset management at Bentley
Systems, was part of a case study panel
at Microsoft's Ignite conference that
explored the need to change how we
deal with bridge inspection compliance
and other issues that owners of bridge
assets face. "Bridge inspection and
management have stagnated over the
years, and the typical approach is that
whether we're talking about
governmental oversight and legislation,
or just as an asset owner, a scheduled
inspection involves inspectors going
into the field, using a range of tools and
other mobile applications, producing
photographs, videos, and audio notes
to record information about the state of
an asset so that we can compare notes
on its condition over a period of time,"
Vogen said. "The production of such
documentation and the submission of
inventory conditions has been going on
for many years."
Vogen continued, "There has been
some evolution in the process, perhaps
a recognition that we can do better,
such as differentiating between a new
bridge and one that is in an area with
difficult physical conditions - salt, sea
water, or heavy weather - requiring a
different approach and more frequent
inspections. In the United States we are
faced with the Federal Highway
Administration's new mandate for bridge
inspections - the National Bridge
inventory guidelines. These new
standards will move inspectors away
from rigid schedule-based to
performance-based inspections."
MICROSOFT'S HOLOLENS AND
DIGITAL TWINS
Vogen described the two critical
processes that has allowed bridge
inspectors to become smarter in the
way they handle bridge inspections. The
first is the use of all available technology
to view and record the condition of a
bridge at a particular point in time, so
that a digital twin can be made of the
structure and its condition. The second
is that Microsoft's HoloLens technology
can be used to create an immersive
view of the bridge using
photogrammetry processed through
Bentley's ContextCapture, so that bridge
inspectors can view and visually
interpret data within their own office
environment.
The second point is important, as it
enables successive inspections to be
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July/August 2021