1. Oregon Schools are getting ready for the Big One!
One in Three
Those are the odds of a major Cascadia Subduction Zone earthquake happening within
the next 50 years. Seismologists are predicting an earthquake with a magnitude of
between 8.7 and 9.2 – commonly referred to as “The Big One” along the Cascadia
Subduction Zone, which runs from Cape Mendocino, CA to Vancouver Island, Canada.
Although no one knows exactly when the next Big One will occur, significant data
indicates we are within the time frame interval of when the Cascadia has historically
released its pent-up energy. The Pacific Northwest could be devastated.
3. The Last Big One
The geological record indicates that these subduction zone earthquakes have been
occurring in the southern end of the CSZ nearly every 240 years with a magnitude of
approximately 8.0, and along the full margin of the CST every 400-600 years with a
magnitude of 8.7 to 9.2. The Oregon Legislature has taken notice and last year
approved a sale of $175 million in bonds to fund seismic safety grants for schools. In
April, Business Oregon, the state’s economic development agency, awarded 41
recipient schools grants ranging from $289,000 to $1.5 million for seismic safety
upgrades. This first round of grants totaled $50.3 million. A second round of grants
totaling $125 million is anticipated to be awarded to schools this June.
How Can Ausland Help
Since our founding, Ausland has focused on complex and technically intensive projects,
with a particular affinity towards fast-track renovations, and on fostering close
collaboration between our team and the clients we serve. Throughout the years, we
have chosen projects where our dynamic, educated, experienced, and technically
advanced team of professionals can excel. We seek out challenging projects that fit our
distinctive skill set and unique resources like the seismic renovation of the schools
funded by these grants.
Examples of similar projects Ausland has helped clients seismically improve the safety
of their buildings includes:
4. Churchill Hall Rehabilitation – Southern Oregon University – Ashland, OR
This $5M project consisted of a complete interior renovation and seismic upgrade to
the oldest building on campus (circa 1926). Home to the President’s Office and
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istration, the project was carefully coordinated around existing building functions and
staff schedules. During the process, Ausland developed an alternate method for
funneling 350,000 pounds of steel into the building without removing the roof, saving
the University $500,000.
Historic Jacksonville Courthouse – Jacksonville, OR
Listed on the National Historic Registry, the preservation of the Jacksonville
Courthouse, including its existing features, was of the highest importance. This seismic
renovation included installing brackets and hardware to the original wood joists and
anchoring them to the existing masonry walls to reinforce and strengthen the building
and prevent the floors and roof from possible collapse in case of a seismic event.
Applegate Elementary School Renovations, Applegate, OR
The school children of the small community of Applegate had to be set-up in makeshift
modular units because of the unsafe conditions of this 100-year-old historic school
building. Ausland led the entire award-winning process of this Design-Build project,
completing comprehensive seismic safety and structural improvements, as well as
substantial systems and architectural renovations ahead of schedule. Today, the kids
of Applegate, Oregon enjoy a safe classroom environment in this unique historic
building.
Seismic Evaluation of School Buildings in Oregon
The building code currently in force in Oregon is the 2014 edition of the Oregon
Structural Specialty Code (OSSC), which is based on the 2012 International Building Code.
According to this code the seismic risk category for elementary and secondary schools
is III. They are not generally classified as “essential facilities” (risk category IV) unless
they are also designated to be emergency shelters or emergency response operation
centers. The seismic importance factor Ie is adjusted accordingly. What this means is
that for most schools the level of design is for life/safety. That is, if the school is not
designated as an essential facility it may be damaged in a large earthquake but it must
not collapse or fail in a manner that would threaten those inside. Spectral response
acceleration parameters, both mapped and design, can be downloaded from the US
“The Churchill Hall project by Ausland was one of the best values for any
capital improvement I have been associated with.”
- Drew Gilliland, Facilities Director, Southern Oregon University, Owner
5. Geologic Survey web site, and design procedures are described in the American
Society of Civic Engineers (ASCE), Code Standards 7: Minimum Design Loads for
Buildings and Other Structures as modified by the OSSC.
We know that seismic risk is much greater west of the Cascade mountain range than
east as seen in the Big One map above. Seismic loads result from sudden ground
movement. A building has inertia that is proportional to its weight. When the ground
moves suddenly inertia causes the building to resist moving with it and shearing forces
develop between the ground and the building and also between the building roof and
upper floors and the foundation. A direct load path from roof to foundation is
required. The heavier the building the larger the resulting forces. The taller the
building the greater is the demand placed on the load path.
The school buildings in Oregon are for the most part one or two-story structures with
flexible diaphragm (wooden) roofs. Wood-framed structures are relatively light and
resulting seismic forces are relatively small. Seismic upgrades of single-story wood-
framed structures usually entail little more than strengthening connections between
roof and walls and between walls and foundation, though sometimes it is necessary to
add or reinforce existing shear walls with plywood. Occasionally a steel frame may be
required to carry load around an opening. In 2-story wood-framed structures it may
also be necessary to strengthen connections between upper floor framing and walls.
Upgrading masonry buildings can be more complex. The starting point to break down
complexity into efficient seismic renovation solutions is always a thorough inspection
of the structure and an investigation of all existing documentation. Masonry is both
heavy and brittle, and the resulting seismic forces can be large. Again connections
between walls and diaphragms and between walls and foundation are critical, but the
brittleness of masonry adds the risk of possible catastrophic failure. Reinforced
masonry can be designed to withstand large seismic forces but most older masonry
buildings are not reinforced, and walls may require external reinforcement, often in the
form of braced steel frames.
Other remediation options such as dynamic dampers and base isolation are available
but these are seldom cost-effective for relatively small buildings like schools. We
believe that simple strengthening will typically prove to be the most reasonable
approach for seismic upgrade of the Oregon school buildings under consideration. In
addition to strengthening the seismic force-resisting systems it is also necessary to
securely fasten all permanent components such as electrical and mechanical equipment,
bookshelves and so forth so that they cannot cause injury by falling on someone in the
event of an earthquake.
Gregory W. Ausland. P.E.
Principal | Ausland Group
