December 16, 2015-January 5, 2016 —
COLORADO REAL ESTATE JOURNAL
— Page 29
Construction, Design & Engineering
M
ost architects and
builders would agree
that saving an out-
dated building from demolition
and repurposing it for a new use
is the most sustainable solution
structurally, yet this approach isn’t
considered often enough. Keeping
the majority of an existing struc-
ture intact, along with all of its
embodied energy, well-designed
upgrades and additions can trans-
form buildings into world-class
facilities that offer greater flexibil-
ity for future needs. Reuse also can
save the cost of demolition and
substantially minimize the carbon
footprint.
As developers and owners con-
sider tapping their existing build-
ing stock to expand their port-
folios and minimize their carbon
footprint, the structural engineer-
ing industry can help revitalize
and adapt these buildings for uses
never considered when they were
first built.
The approaches our firm has
used to accomplish this on recent
projects in Colorado successfully
demonstrate that savingabuilding
does not have to be overly expen-
sive. Take the Lory Student Center
(Phase II) on Colorado State Uni-
versity’s Fort Collins campus, for
example.
TheoriginalCSUStudentCenter
designed by architect James Fisher,
was a midcentury Bauhaus build-
ing completed in 1962 with clean
lines, a regular grid and an open
floor plan. As time passed, new
building additions began to mask
many of the building's good fea-
tures, resulting in increasingly con-
fused wayfinding and orientation
for students. In 2010, the university
hired design
architect Per-
kins + Will,
with ALM2 as
the local archi-
tect of record,
to
address
these issues
and
more.
The architects
env i s i oned
p r e s e r v i ng
the integrity
of the original
design while
expanding the
center’s capac-
ity to meet the needs of a growing
campus. They concluded that by
increasing the building’s size to
grow student services, opening up
views to themountains to facilitate
easier wayfinding and expanding
the ballroom (the largest gather-
ing space in Northern Colorado),
a more welcoming, vibrant hub
would drive increased student
visits to the heart of the campus.
Further, theseupgradeswouldcre-
ate one of the most sustainable
student centers in the country.
In addition to wayfinding
issues, energy usage was chal-
lenged by the building's original
1960s mechanical systems, single-
glass pane exterior envelope and
minimally insulated walls. CSU's
budget didn’t allow for wholesale
demolition of the existing build-
ing and replacement with a new,
larger building, so the architects
turned to Studio NYL to come
up with structural strategies that
would help them achieve their
goals.
To support the architects’ ulti-
mate vision we proposed using
external FRP
(fiber
rein-
forced poly-
mers)
to
enhance the
original cast-
in-place con-
crete flat plate
floor
slabs,
while
also
checking the
columns and
upgrading the
foundation for
the increased
loads.
The
FRP solution,
which they chose to implement,
solved two things simultaneously:
• It upgraded the floor’s live-
load capacity in lower-capacity
areas so uses up to 100 pounds per
square foot could be placed any-
where inside the building, allow-
ing the university to have ultimate
flexibility for the future; and
• The FRP strengthening, bond-
ed to the underside of the floor
slabs,requiredonly¼-inchofspace
(unlike themore common solution
– a 12-inch-deep fire-proofed steel
beam grillage placed below the
slab). Thus, with floor-to-ceiling
heights of only 12 feet and ceiling
heights at 10 feet,which isminimal
for the uses proposed, this allowed
for ample headroom throughout
the building.
One of the advantages of FRP
systems (typically carbon, glass
or aramid, with carbon being the
strongest) is that they are easily
applied by small crews of two to
three people after lightlypreparing
and cleaning the existing concrete
surface to remove laitance (amilky
deposit or accumulation of fine
particles on the surface of new
cement or concrete). An epoxy-
bonding agent is then applied,
onto which the FRP is adhered.
On this project, a variety of FRP
forms, which come in sheet wrap
or narrow strips, were applied in
various orientations, spacing and
number of layers to match the
given load demands in each area
of the structure. The underside of
the slabs were reinforced in the
middle of the bays, while the top
surface of the slabswere reinforced
around the column locations. The
engineers at Studio NYL liken it to
applying “structural wallpaper” to
increase the strength of a structure.
An added benefit of using FRP
systems on this project was the
Christopher
O’Hara, PE
Founding principal,
Studio NYL Structural
Engineers, Boulder
Julian Lineham,
PE
Founding principal,
Studio NYL Structural
Engineers, Boulder
The new Lory Student Center at CSU’s Fort Collins campus demonstrates
how cost-effective structural strategies can be used to repurpose out-
dated buildings.
Lory’s two-story glazed addition includes reinforced floor openings that
allow daylight into lower levels for the first time (on right).
