“Once we put the fixed roof on and tinted it to
a point where everyone would be comfortable, there
was not enough sunlight energy to grow grass so we
decided to go with a retractable field option where
it slides out of the stadium,” which Manica describes
in detail.
“This is not the first time this has been done, but this
is the next generation of that technology. Again, this
came with challenges. When locating the project with a
sliding field, you have to consider which end of the
building it will slide out of and were it will dock. The
easier thing to do would have been to push the stadium
away from the strip and have the field slide out of the
peristyle end as that’s the lighter end of the building
due to less architecture. But this would have made the
views worse and if you were standing at the peristyle
end you would have been looking over a blank concrete
pit where the field slides through, so that’s not ideal.
“What we ended up doing was moving the stadium
as close to the strip as possible, with the peristyle on
that end, and pushed the field out the other way. The
field is now sliding under the heaviest part of the
structure, where there are the most seats and levels,
unlike Arizona Cardinal’s stadium in Phoenix, where
it slides out where nothing is there. We had to slide
a field out under an entire building. The real
engineering feat of the whole project I think is the
column-free bridging that holds up an entire end
of a football stadium so the field tray can slide
underneath it,” he adds.
Over125k
cubic yards
of concrete
poured
Going all in
It was decided early on that the project would take
a design-build approach, where the design has been
finalized but elements of the stadium continue to be
designed and engineered during construction. It is the
largest design-build that has ever been carried out at
a sports venue, however HNTB has experience having
executed a similar approach for the Denver Broncos in
2001 and at Levi’s Stadium for the San Francisco 49ers.
“The approach is different. It allows the architects
to work directly with the owner during the period of
concept and schematic development, which influences
what the building looks and feels like. Then it’s
transferred to the design builder for completion. This
allows you to compress the schedule as you have
concurrent activities going on, and allows the owner
to control the critical stages of the design while giving
cost assurances once they do the GMP and go forward,”
says HNTB’s Lanson Nichols.
With an unrelenting schedule where the number
of individual daily tasks most days could be upwards
of 50,000, the approach has proven to be a great success
in keeping the project on schedule and on budget.
“The decision behind the approach was driven by
the fact the price of the project was absolute, and the
Raiders saw it as a way of controlling the risk of the
cost of the build. In spite of market conditions related
to steel and Covid-19, both of which could throw
schedules out by a year, the setup worked really well
and it remains on track to open on time,” says Manica.
ALLEGIANT STADIUM
18 www.stadia-magazine.com June 2020
/www.stadia-magazine.com