DFI Magazine September/October 2020 - 81

A poll taken at the beginning of the first webinar
revealed that the audience was
diverse (see graphic). It was
disappointing to note that
there were no architects: this
needs to be focused on for
future webinars as they, along
with building owners, make
the key initial decisions on how
buildings will be heated and
cooled. Incorporating energy
foundations from the outset of
a project helps ensure that these
foundations stand an excellent chance of
becoming reality.
Delivering successful energy foundation solutions, from a technical and
contractual sense, involves many engineering trades including geotechnical,
structural, mechanical and electrical
engineering. It takes someone with a good
handle on knowledge across all these fields
to deliver a successful heating and cooling
solution from the energy foundation (i.e.,
inhabitants' comfort is secured, and
foundations' performance is unimpaired).
This is true regardless of the building type a
heating, ventilation and cooling (HVAC)
system is going into.
The Energy Foundations webinar series
was structured to run over three, 1.5-hour
sessions to cover the information as an
engineer would use it:
* Session 1 (July 8, 2020): Review
research, substantiate a solution works,
and, importantly, verify the solution
does not affect the foundations.
* Session 2 (July 15, 2020): Review what
specifications and standards need to be
considered as part of the energy
foundation solution.
* Session 3 (July 22, 2020): Build a system
that gets it right the first time through
good quality assurance and controls.
The sessions were led by international
energy foundation experts who have spent
the last 15-20 years analyzing and raising
the profile of energy foundation solutions
and verifying the effect geothermal loops
can have on foundations.
Peter Bourne-Webb, Ph.D., CEng,
Instituto Superior Técnico, Lisboa,
Portugal, set the scene in the first webinar

Poll at Energy Foundations webinar

and provided a review of research that had
been completed to date into how piles
respond to thermal loading from being
heated and cooled and the likely thermal
stress responses that occur, before considering the long-term impact of annual
cyclic thermal loading and the importance of
selecting a suitable factor of safety in foundation design. Bourne-Webb concluded that
thermal loads do not affect geotechnical
resistance and confirmed that no evidence of
cyclic degradation of shaft resistance existed;
however, in terms of structural safety,
thermal stresses need to be considered on
piles that are already highly stressed.
Alessandro Rotta Loria, Ph.D., P.E.,
Northwestern University, provided a
research overview on a different form of
energy foundation and the impact of
geothermal loops installed within structures
such as tunnels, slurry walls and slabs and
the thermal effects/impacts and benefits of
having one face exposed on structure design
and heating and cooling outputs.
In the second webinar, we learned about
the importance of coordination and
ensuring a good understanding of responsibilities between the many players that are
involved in the design process of a building's
heating and cooling solution. Geothermal
designer Ed Lohrenz, B.E.S., CGD,
GEOptimize, outlined the key parameters
required in designing energy foundation
solutions and, most importantly, the need
for an accurate and detailed annual (8,760hour) heating and cooling energy profile for
a building, and how simple changes to a
building's shape, windows and insulation
can affect outputs and ensure a balanced
heating and cooling load for energy
foundation system longevity.

Lance MacNevin, P.Eng.,
Plastic Pipe Institute (PPI),
discussed what types of plastic
material and geothermal loop
selection were available, along
with providing direction on
specification information and
fusion of joints in pipework.
Fleur Loveridge, Ph.D.,
CEng, from University of Leeds,
U.K., provided an insightful
review of lessons learned and
how to successfully prescribe a
conductivity test to confirm values to be
used in energy pile design for small-to-large
diameter piles.
The third webinar covered the importance of good coordination and clear
responsibilities, this time for the teams on
the construction site and by ensuring
sufficient quality assurance and controls are
in place at key project stages to ensure
successful installation of energy foundations. Jason Hertz, MBA, P.E.,
GeoStructures, provided us with some
lessons learned and the QA/QC measures
implemented on a project in New York City.
Webinar Co-Chair Guney Olgun,
Ph.D., Missouri University of Science and
Technology, described alternative energy
foundation solutions that are available and
the research he has undertaken into bridge
deck deicing, which could also be considered for snow melt facilities for roads,
sidewalks and airport taxiways.
The three sessions together provide a
great source of knowledge and references,
outlining where to go and what considerations are needed in developing a successful
energy foundation solution. What is clear is
that energy foundation solutions have many
benefits and can have minimal impact on a
construction schedule as long as good
coordination between all parties from the
outset is established; most importantly, it
provides an answer to building low to zero
carbon buildings and is an excellent
solution that will help meet the carbon
reduction goals around the world.
Finally, I would like to thank the DFI
team - Mary Ellen Large, Jaime Cettina,
Carol Planitzer, Fern Dickey and Angie
Gibble, who helped pull this webinar
together and made it a success; we couldn't
have done it without you.
DEEP FOUNDATIONS * SEPT/OCT 2020 * 81
DFI Magazine September/October 2020

Table of Contents for the Digital Edition of DFI Magazine September/October 2020
