School Seismic Safety
   

The School Seismic Safety Project (SSSP) is a statewide effort to evaluate how Washington public school buildings could be affected by earthquake shaking.

Project Overview

Many of Washington’s K–12 students attend schools that may not withstand earthquake shaking. Washington State ranks second in the nation for earthquake risk, but most of Washington’s public school buildings were built before the adoption of modern building codes that are up to date with seismic standards.

What is the School Seismic Safety Project?

The School Seismic Safety Project (SSSP) is a multiphase, statewide effort to systematically evaluate Washington school buildings for seismic performance. Phase 1 of the SSSP, completed in June 2019, was funded through the 2017–2018 Capital Budget and assessed 222 school buildings. Phase 2 is a 2019–2021 Capital Budget-funded project that is currently assessing a new selection of schools. The SSSP is led by the Washington Geological Survey (WGS), a division of the Department of Natural Resources (DNR), in cooperation with the Office of Superintendent of Public Instruction (OSPI). The results of the SSSP inform schools, districts, and public officials of the policy and funding needs for improving the seismic safety of our state’s K–12 public school buildings.

What Work is Involved?

The project involves both geological and engineering assessments at each school. WGS scientists collect seismic data to measure how local soils amplify earthquake shaking at school campuses, usually on playing fields. This seismic data greatly improves our estimates of potential ground shaking by more accurately evaluating site-specific soil conditions under the school buildings. In addition to this, a group of licensed professional structural engineers collects building data at the school campuses. They evaluate the structural and nonstructural adequacy of the school buildings per the ASCE 41-17 checklist, a tool for evaluating how buildings will withstand earthquakes. Combined, these assessments provide a detailed view of how earthquake shaking might affect each school.

School Selection

Geologic and engineering factors affecting school seismic safety

Many things affect how a school building will be impacted by earthquake shaking. Major geologic and engineering factors considered during school selection are described below.

Ground Shaking

An earthquake’s proximity, magnitude, and depth all play an important part in whether a school building will maintain its structural integrity during an earthquake. Washington State could be affected by numerous sources of earthquakes, including a subduction zone offshore and numerous active crustal faults. You can learn more about earthquakes and how they could affect Washington on our earthquakes webpage.

Simplified map of seismic hazard. Colors represent shaking hazard, with darker colors indicating higher hazard areas. Major active faults are shown as black lines.

Ground Conditions

The earth materials beneath school buildings can amplify ground motion during earthquakes. Fine-grained soils such as silts and clays are more prone to liquefaction, where the soils lose cohesion and behave like liquids. Buildings situated on materials such as clays and silts typically require the incorporation of stronger reinforcements than buildings sited on bedrock.

Building Age and Type of Construction

Building age is one of the most significant factors affecting the seismic vulnerability of a structure. Most (88%) of the permanent public K–12 school buildings in Washington were constructed prior to 2005, which means they do not incorporate expected shaking from a Cascadia subduction zone or Seattle Fault earthquake into their building design and type of construction. Buildings constructed before 1998 are especially at risk, as this is the first year when buildings began to be constructed to “modern” seismic standards.

Non-Structural Building Components

Regardless of the age, type of construction, or building type, there are many non-structural deficiencies in schools. These deficiencies are important to identify and mitigate as they can also be problematic during an earthquake. Examples of non-structural components include: mechanical, plumbing, and electrical systems, shelving, interior partitions, and parapets.

School Selection Process

Various criteria were considered in the selection of schools for Phase 1 and Phase 2 of the SSSP. Phase 2 selection included all the criteria considered for Phase 1, with the addition of bond district and tsunami risk factors. These selection criteria are shown in the graphic below.

Project Timeline

Phase 1

Phase 1 of the SSSP (the 2017–2019 biennium) is complete.

The School Seismic Safety Project began in June 2018 with geologic field assessments and engineering building surveys. In the fall and winter of 2018 through the spring of 2019, scientists and engineers assessed the data collected in the field and wrote up their results for each school. The final report for the project was finished in June 2019 and submitted to the governor, the legislature, and the school districts who were a part of the study. All the reports for Phase 1 of the SSSP are available for download under the 'Download Phase 1 Reports' section on this webpage.

As part of Phase 1 we (1) assessed the NEHRP seismic site class at 94 school campuses and five fire stations, (2) performed seismic evaluations of 222 public school buildings, and (3) performed more detailed seismic analyses for 15 of these 222 buildings in order to evaluate seismic upgrade strategies and determine how much it may cost to bring each building up to current seismic building codes.

Phase 2

Phase 2 of the SSSP (the 2019–2021 biennium) is in progress.

The second phase of the School Seismic Safety Project began in September 2019 with geologic field assessments and building inspections at 339 school buildings. In the fall and winter of 2019 through the spring of 2020, scientists and engineers continued to collect data and write up their results for each school. The final report for the project will be finished by the end of June 2021. Once the individual reports for each school are finished and the final project report is submitted, this website will be updated with links to the new information.

Project Activities

Assessment of school seismic safety included three components: (1) an initial seismic screening evaluation by structural engineers at all selected schools, (2) a seismic site class assessment conducted by geologists at all selected schools, and (3) a more detailed concept-level seismic upgrade design developed by engineers for a small subset of participating schools. These activities are described in more detail below:

An initial seismic screening evaluation includes:

  • An on-site investigation of the school buildings to screen for potential hazards. Licensed structural engineers evaluated building type, age, configuration, condition, and other features in order to determine how the building would react during an earthquake.
  • Creation of a seismic screening report to document the findings from each school building. These reports will be distributed to each school and district to support further seismic improvement work.
  • Input of this seismic screening information into the Office of Superintendent of Public Instruction’s (OSPI) Information and Condition of Schools (ICOS) database so that results and reports are available to OSPI and are captured in the statewide database of school information.

A site class assessment of each school campus involves:

  • An on-site assessment of the seismic site class of the soils using geophysical methods. Seismic site class is related to soil type and determines the level of earthquake shaking expected at the site. Read more about these assessments below.
  • Creation of a site class assessment report for each campus that also takes into account the other geologic hazards that potentially could impact school structures.

A concept-level seismic upgrade design conducted at a small subset of schools includes the initial seismic screening evaluation plus the following:

  • Drawings that show how seismic upgrades could be made, as well as a review of how the proposed upgrades would affect the architecture of the school. Changes in architecture would affect whether the building would keep people safe during an earthquake and whether the building could be used again immediately following the earthquake.
  • Creation of a design report for each facility.
  • Additional screenings and calculations to determine a cost-effective way to seismically upgrade the school building, including a final estimated cost to upgrade.

The concept-level seismic upgrade designs provide: (1) more detailed information about the structural and nonstructural seismic deficiencies of each building, where structural refers to the building structure and framing and nonstructural refers to components such as architectural features and finishes, building envelope, and mechanical, electrical, and plumbing systems; (2) design solutions for how to lessen the impact of these seismic deficiencies in the event of an earthquake; and (3) an estimate of how much it would cost to bring the building up to seismic code. Based on this information we can extrapolate our findings to other buildings in the State. This will help us better understand the scope of seismic risk and the cost to conduct seismic upgrades for all schools across Washington State.

Seismic Site Class Assessments

At each school campus a team of DNR geology personnel conducted a seismic survey to determine the National Earthquake Hazard Reduction Program (NEHRP) soil site class at that school. Site class categories inform scientists and engineers about how the soils under a school might amplify ground motion during an earthquake. We determine site class for a school by measuring how fast shear waves move in the upper 30 meters (98 feet) of the ground. Shear waves are the earthquake waves that create the strongest shaking and are the most damaging to buildings during an earthquake. This measurement, known as Vs30, is correlated with site class using the table shown below. Different types of soil and rock can make earthquake shaking stronger at the surface. Site class therefore tells us about the potential for ground shaking in a particular area during an earthquake. Engineers use the site class information for a school to ensure that the building upgrades will be able to withstand the expected amount of shaking at that location.

NEHRP site class categories. By measuring Vs30 we can use this table to identify the composition of the soils beneath a structure. Softer soils typically make ground shaking stronger.

  NEHRP site class Description Vs30 (meters/second) Ground shaking potential
A Hard rock greater than 1,500 Low
B Rock 760–1,500  
C Soft rock/very dense soil 360–760 Moderate
D Stiff soil 180–360  
E Soft soil less than 180 High

Phase 1

Phase 1 of the SSSP provided funding for the assessment of 222 school buildings and five fire stations within one mile of a school. For this phase, 15 buildings were selected for a more detailed concept-level seismic upgrade design. More information about how the assessments were conducted is available in the ‘Project Activities’ section of this webpage. More information about how schools were selected is available in the ‘School Selection’ section of this webpage. Click here to download a table with the names of all 222 school buildings studied as part of Phase 1.

Map showing the locations of all 222 school buildings studied as part of Phase 1. The 15 school buildings selected for further analysis are shown as darker circles.

Phase 1 Major Findings

  • Nearly a quarter of the school campuses have a measured site class that differed from previous estimates of site class made based on broad-scale geologic maps. These differences can significantly affect building upgrade cost estimates and building designs.
  • About half of the school buildings were built before 1963, well before the adoption of modern seismic codes. Building age and material is a key indicator of the need for a seismic upgrade. Older unreinforced masonry buildings and non-ductile concrete buildings are especially at risk. Buildings constructed prior to 1998, when the statewide building code was adopted, are particularly vulnerable.
  • The Earthquake Performance Assessment Tool (EPAT) estimates that:
    • The median building is expected to be 43 percent damaged by a design-level earthquake (a modeled earthquake that could be similar to a Cascadia subduction zone earthquake in some parts of Washington).
    • The majority of buildings are expected to receive a “Red—Unsafe” post-earthquake building safety placard following a design-level earthquake, meaning that the buildings may be unsafe to occupy.
    • Approximately one-fourth of buildings studied may not be repairable following a design-level earthquake, and will require demolition.
  • Many of the schools with the highest estimate of damage following a design-level earthquake are located in areas of highest earthquake hazard.
  • The results of the more detailed concept-level seismic analyses indicate that the cost to seismically upgrade a vulnerable structure is less or much less than the damage costs the building would incur in an earthquake. For less vulnerable structures, it may not be financially worth conducting seismic upgrades.
  • Based on the limited number of buildings (15) where seismic upgrade cost estimates were made, the average cost to upgrade to the Life Safety standard (meaning the building will keep people safe and provide exits, but won’t necessarily be useable after the earthquake) is $42 per square foot. The average cost to upgrade to the Immediate Occupancy standard (meaning the structure is built to be useable after the earthquake) is $69 per square foot.
  • Estimated costs to seismically upgrade a school building range from $63,000 per building to $5,010,000 per building.

Download Phase 1 Reports

This section provides links to reports on SSSP methods and findings.

  • The initial progress report submitted to the legislature on September 28, 2018 can be found here.
  • The final Phase 1 report submitted to the legislature on June 28, 2019 can be found here.
  • Four engineering reports outline the results of the seismic screenings:
  • A publication detailing the methods and results of the site class assessments, including an appendix containing the reports for each of the school campuses, can be found here.

The map below allows you to download the Tier 1 engineering seismic screening reports for each of the school districts. Click on each district to access a link to the report.

Tier 1 engineering seismic screening reports are also available for each of the five fire stations:

The concept-level seismic upgrade design reports are available bundled as Volume 4 above, or individually for each school building by clicking on the names below:

Phase 2

Phase 2 of the SSSP is currently in progress, with funding for the assessment of 339 school buildings and two fire stations within one mile of a school. For this phase, 17 buildings were selected for a more detailed concept-level seismic upgrade design. More information about how the assessments were conducted is available in the ‘Project Activities’ section of this webpage. More information about how schools were selected is available in the ‘School Selection’ section of this webpage. Click here to download a table with the names of all 339 school buildings studied as part of Phase 2. All the reports produced during Phase 2 will be made available for download on this website at the end of June 2021.

Map showing the locations of all 339 school buildings studied as part of Phase 2. The 17 school buildings selected for further analysis are shown as darker circles.

Progress To Date

  • In partnership with an engineering firm, the team underwent a ranking process to select schools for participation in Phase 2, using the criteria provided by the legislature. 161 schools volunteered to have site class assessments and structural inspections performed for 339 buildings using the ASCE Tier 1 checklists at each campus. Additionally, the team is performing the same analyses at two fire stations that are located within one mile of a school campus.
  • The WGS team of geophysicists is in the process of completing site class assessments at all participating school campuses.
  • The engineering firm has performed assessments at nearly all of the selected buildings to date, and they are currently working on completing concept level designs for 17 of those schools.
  • The School Seismic Safety Project team is also preparing individual site class assessment reports for each school campus, which will include the site class information, along with other geological hazards that may impact the school.
  • Information gathered during this project will soon be compiled into a final technical report that will be provided to the legislature by the end of the fiscal year. Data from this project will be provided to the Office of the Superintendent of Public Instruction to augment their Information and Condition of Schools (ICOS) database, and will help to identify and prioritize seismic retrofits at schools.

Meet The Team

For general questions about the SSSP, contact Corina Allen. For specific questions about the seismic site class assessments and selection of schools for inclusion in the project please contact Travis West.

Travis West
SSSP Project Lead
360.902.1481
travis.west@dnr.wa.gov
Jade Cooley
SSSP Project Assistant
360.764.0031
jade.cooley@dnr.wa.gov
Alex Wernlé
SSSP Project Assistant
360.902.2174
alex.wernle@dnr.wa.gov
Corina Allen
Chief Hazards Geologist
360.902.1455
corina.allen@dnr.wa.gov