We sat down with Structural Associate Principal Ben Barlow and Civil Associate Principal Keith Kruger to talk about Mount Si High School, one of the largest high schools in the state, uniquely situated on an elevated plaza above Snoqualmie’s flood plain.
Tell us a bit about the project.
Ben: Mount Si High School represents a complete replacement of the existing high school. It features multiple, three-story classroom buildings located on a shared podium over a new parking garage and incorporates a separate Freshman building. The project includes incredible common spaces with student amenities, a large gymnasium and athletics building, a full-featured auditorium, a state-of-the-art-shop and robotics facility, and a multitude of modern learning environments.
What made this project different?
Ben: There were unique challenges related to the site and its location in a flood plain over a deep, old lakebed with poor soils. To address the poor soils, a deep ground improvement system was utilized, and a site-specific seismic analysis was performed, both of which are uncommon for schools in this area. The final design elevates the school above the ground to allow flood water to pass beneath the structure. It simultaneously provides permanent parking and reduced the amount of on-grade parking that would otherwise have been required.
Keith: This was a super complicated site when it came to stormwater design: two different drainage basins (each with their own specific requirements) and the school’s location in a floodway and a flood plain.
The floodway and flood plain required multiple design solutions to ensure the campus build didn’t affect flooding for the surrounding community. In addition to raising the parking structure as Ben stated, large pipes were placed below the new athletic field — again, so flood waters could pass below the field, mirroring the existing conditions.
Why did you like working on this project?
Keith: Challenging projects are the most intriguing to work on. In addition to the flooding issues, this project was heavily phased, which required a lot of unique design solutions to make the sequencing work.
Ben: Mounti Si really challenged me from a management standpoint. The scope of the project, the size of the team, the schedule and complicated phasing – each required special attention to get our team to the finish line. We solved some incredible engineering feats. Although difficult at times, we ended up with great stories to share.
Do you have a favorite feature? Any engineering standouts?
Ben: A few. There’s a large, cantilevered space in the library; the overhang is suspended from steel trusses above. The auditorium features another large, cantilevered balcony that required a unique tapered truss shape. The elevated garage beneath the school required significant coordination between our team and NAC to optimize the parking structure with complex programing above.
Keith: The ‘flow through’ culverts below the field are quite impressive. I wonder what the casual passer-by thinks of them!
What was the biggest challenge the team faced?
Ben: This was one of the first projects for our office that used Buckling Restrained Braces (BRBs) for the seismic system. This high-performance seismic system is very efficient at dissipating energy and allowed us to reduce the seismic demands on the foundation system. It was an engineering solution critical to this project due to the relatively tall structure and the poor soils. We learned a lot about the system along the way, and now use BRBs on many of our projects.
Keith: Grading! The Snoqualmie Valley is extremely flat, so getting pavements and pipes to slope enough to drain was very challenging.
What was one thing you learned during this process?
Keith: The city basin maps were incorrect, making our initial design assumptions inaccurate. Working through the disparities confirmed that field verification is absolutely critical to the success of a project.
Ben: It reinforced the critical importance of a well-organized workplan for the project team. It was so important to provide clarity of roles for team members and to define deadlines to keep this large program on track. The size of the project demanded that we invent new management tools, many of which are now implemented on live projects.
I liked working with …
Keith: NAC really led the team well. Matt Rumbaugh and Brent Compton were/are great to work with.
Ben: Agree with Keith. The NAC team. Everyone involved in the project was fun to work with, incredibly nice and energetic. The team was open-minded, really listened to our input, and was willing to adapt their design to address the unique challenges of the project. I found this collaboration to be crucial to pulling off this project, and it also made the whole team feel valued and invested.
How does this project impact the city or its community?
Ben: It’s definitely the biggest building in town! For the district, it represents a huge commitment to their educational program and to the residents of Snoqualmie and surrounding areas. It sets the community up for future capacity and prepares students for success using technology and state-of-the-art learning tools.
What is it like to see the finished product?
Keith: This was one of the most complicated projects I’ve worked on. Seeing it constructed was a huge relief and point of pride for our whole team.
Ben: The scale of it stands out for a K-12 school. It sits on an elevated, floating platform that gives it a unique feel – like you’re entering a new separate world. It feels more like a university campus. You especially notice the size and magnitude of it when you’re in grand, open spaces like the gymnasium and the auditorium.
A few quick-fires from Ben::
And from Keith:
Images © Benjamin Benschneider