FEATURE ARTICLE: Latest PNW Code Updates

In the last 30 years, seismic codes have been trending toward higher requirements, evolving by tiny percentages at a time. But next summer (July 2020) the building code for new construction will change drastically, increasing seismic requirements by 30 to 100 percent. It’s an unprecedented jump that goes far beyond the standard changes (that only us code nerds find fascinating). The updates are significant and will be felt industry-wide, especially here in the Pacific Northwest.

1. What’s driving these changes? Why such a great jump in requirements? And why now?  These are national changes driven one hundred percent by geology and ground motion. Because of our geology and location, the new requirements have a huge impact here. Not only does our region have some of the most unique seismic geology in the country (Its proximity to the Cascadia Fault off the Washington coast, as well as the deep glacial deposits of the Seattle Basin which amplify seismic waves from Tacoma to Everett), but new research has yielded findings that weren’t considered in previous code cycles. Additionally, the current code cycle is especially unique as it coincides with the major seismic code evaluation that occurs every five to ten years. It’s a double whammy of sorts.

2. With the code dropping next summer (July 2020), what should owners, architects and AEC professionals expect? First, it’s important to understand the timeline for projects starting now that may be permitted under new code. Vesting varies by jurisdiction, so it’s important for the project team to discuss. This means something different for each stakeholder. Owners should be prepared for increased building costs. Architects should expect impacts on lateral system layouts. Some previously acceptable offset core layouts may need to be supplemented with additional perimeter elements or replaced with a centered system. As structural engineers, we’re preparing for increased structure cost by exploring solutions that we believe can mitigate negative impact through creative layouts and advanced analytical techniques. Additionally, we’ll use new approaches with time-tested technologies like seismic dampers – shock absorbers for earthquakes.

3. What’s an example of a new requirement? A site-specific geotechnical analysis will now be required for most buildings on softer soils which are common place in the Puget Sound. Previously, only buildings on liquefiable soils required such analysis. This may mean working with the geotechnical engineer earlier in the design process.

4. What’s happening behind the scenes on seismic committees? What are the challenges you anticipate?  Recent local research, like UW’s M9 project, has given seismic committees like SEAW’s Earthquake Engineering Committee, new data to evaluate and contend with. As the national and local code cycles merge this year, the greatest challenge is timing. Committees must make sure research is correctly represented both locally and nationally.

We’re looking forward, working on proposals which refine the seismic code and doing our best to infer where ongoing research will lead us.

5. What can teams do to prepare for the July 2020 code change? Engage your structural engineer early! We’ll help determine if/how your project will be impacted by the local geologic research and national code changes.

You can also schedule a presentation with us! The presentation we created to prepare our internal team for the coming code changes has been adapted so it’s a fit for your project team. We’d be happy to host you or coordinate an office visit.

Seattle is considering a mandatory ordinance demanding the retrofitting of all unreinforced masonry (URM) buildings. California adopted a similar mandate a decade ago, and Portland followed a few years later. In a way, Seattle is behind the times compared to other major West Coast cities. But the implications of such a rule are widespread, as a study identified more than 1100 Seattle-area buildings requiring retrofits. Balancing safe buildings with manageable requirements for building owners is a challenge that will take the efforts of the entire community.

1. For those who may be unfamiliar, why are URM buildings so dangerous?  URM buildings are dangerous as a class because the brick is brittle in an earthquake. It’s also heavy, so all of its mass is prone to move and fall. Not only are the brick, load-bearing walls a recipe for full collapse, but often these walls aren’t attached to the floors, leading to wall-to-floor separation.

2. You talk to clients and partners about this topic all the time. What is the URM item you find yourself explaining most often?  I do have a URM conversation about once a week! Currently, in Seattle, all seismic upgrade requirements are triggered. This means if a building owner decides to alter a building, that alteration “triggers” a series of seismic upgrades intended to bring the building up to current standards. There are five different triggers, called the Substantial Alterations Provisions. The city’s interpretation is always evolving so it’s best to partner with a firm who understands both the city and the provisions very well.

3. What are the biggest challenges presented by this ordinance?  As structural engineers, we know URM buildings are dangerous; we know what the issues are, we know how to fix them. But we also understand the complexities of this brand of ordinance. The ordinance will make building upgrades mandatory, not triggered, so building owners will face increased costs (financing a retrofit and construction) as well as potential loss of revenue as they relocate tenants. The city is challenged with supporting so many different owners, and accommodating Seattle’s many historic buildings. For this reason, this ordinance has been slow, even stalled, for some time.

4. What advice can you provide to owners and architects?  Most importantly, hire a contractor experienced in URM retrofits — it will save you money and time in the long run. It’s also important to evaluate buildings early, allowing time to identify issues, plan as a full project team, and find creative solutions.

5. What do you consider the biggest misunderstanding when it comes to Seattle’s URM buildings?  We often hear that a building must be fine because it has been through earthquakes before — this is not the case. Past Pacific Northwest earthquakes have been smaller, deeper underground, and farther away than the potential big earthquakes that can hit the Seattle region.

You can learn more about Seattle’s upcoming URM changes here.

As new wood technology gains traction, especially here on the West Coast, codes are emerging to guide local projects. Recent updates encompass two major changes. The first: Seattle City Council approved the construction of Type III-A buildings up to six stories. The second: Washington State Building Code Council (SBCC) approved new code provisions for “Tall Wood Buildings”, expanding Type IV into four categories that allow up to 18 stories.

1. For those unfamiliar, what does the new 6-over allowance mean?  Six-over buildings typically integrate two or three levels of concrete construction (Type IA), then stack wood framing above. Permitting a sixth level of wood allows developers to replace one level of concrete with a much more economical option: wood.

It’s important to have some context around the decision, which is a result of Housing Affordability and Living Agenda (HALA) and Construction Code Advisory Board recommendations to provide developers a method to cost effectively utilize the 85-foot upzoning happening throughout Seattle. Prior versions of the code allowed wood-framed buildings up to five stories (utilizing construction type VA or IIIA). Currently only the City of Seattle has adopted this code and it’s unknown if neighboring jurisdictions will follow suit.

2. And what about the 18 stories?  The new code provisions organize Tall Wood Buildings (Type IV) into four categories, each with its own restrictions around number of stories, amount of exposed wood framing, and fire resistance rating. This is exciting to the industry because these tall wood code updates open a lot of design doors. We’re able to expand the use of wood materials into new building types that previously would have been off-limits per code.

3. What do you consider the biggest benefits of wood products?  There are many! From a design standpoint, products like mass timber and Cross Laminated Timber (CLT) allow owners and architects to introduce combustible building materials into taller buildings. Also, with the ability to expose some or all of the wood, architects can tap into the desired human response to wood material. From an engineering standpoint, wood is an appealing and viable building material that can be efficiently utilized in tall building heights — well beyond 85 feet. It provides a framing alternative to concrete and steel, which to us, is exciting.

There’s also a kind of universal appeal. Mass timber is good for the environment and the local economy. We have numerous active projects utilizing mass timber products and we’re witnessing the reduced construction time and cost firsthand. We know that mass timber products support carbon sequestration and when responsibly-harvested, can positively affect forests. And we know that a higher demand for mass timber products has, and will continue to, stimulate local manufacturing production and reinvigorate the industry.

4. What do you see as mass timber’s role in the future of Seattle buildings? What roadblocks still exist to owners/developers/architects? Mass timber is a natural fit for Seattle and the Pacific Northwest. As mass timber technology is relatively new to the area, it comes at a premium for a number of reasons. However, given the new tall wood code updates, mass timber should be very cost competitive material to concrete/steel when applied in buildings over 85 feet. Current roadblocks include the following:

a. Seismic Codification: There has been a lot of recent lateral testing of mass timber shear walls; however, they will not be codified for some time. In the meantime, traditional systems, like steel frames or concrete shear walls, can be combined with mass timber to create hybrid systems.

b. Owner/contractor product familiarity: In order to determine actual cost of mass timber projects, the pricing needs to reflect the advantages of this system when comparing to steel and concrete systems. It’s also important to limit the unknown contingencies due to unfamiliarity with the product for taller structures.

5. You visit offices regularly to present on wood design. What are common topics you find yourself fielding? There is still a need for education in much of the field. We help designers and contractors understand how to best utilize mass timber products and how the inherent panelization of the product will save on time, construction cost, and specialized labor. We often get asked to convert current projects to mass timber, which we do happily!

Want to know more? Be a stop on our Mass Timber Road Show! Addressing the structural code changes, we’ve built a presentation especially for architects, developers and contractors who want to further explore wood design. We review the six-story wood code updates and requirements and share design practices and learnings for mass timber systems.

Projected code changes will influence the way we build in the region, particularly in three categories: seismic, URM and wood.

Schedule a presentation with Coughlin Porter Lundeen to learn more about how these changes will affect you.