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Scientists have long said the Pacific Northwest is overdue for a sizable earthquake, and Washington County is preparing by updating four large public buildings.

A seismic retrofit of the county’s Law Enforcement Center wrapped up in March. Currently, general contractor JE Dunn Construction is carrying out a $30 million retrofit of the adjacent Charles Cameron Public Services Building.

The latter building is also gaining a host of workspace security improvements and an overhaul of the north wing’s basement. Also, the HVAC and other mechanical systems are being updated.

鈥淚t’s not just seismic,鈥� Washington County project manager Bassam Khalifeh said. 鈥淚t’s also about solving this water intrusion issue that we’ve been dealing with since the building was constructed.鈥�

In total, the project aims to bring the 22-year-old building up to an 鈥渋mmediate occupancy鈥� seismic standard. This means the building is expected to remain standing, be safe to occupy and be repairable after a large quake. However, the standard acknowledges that mechanical, electrical and plumbing systems will likely suffer serious damage.

SERA Architects principal Becky Epstein is in charge of designing all four Washington County retrofits. Many different techniques can be used to reinforce buildings seismically, and various levels of protection can be attained, she said.

鈥淭here are concrete shear walls, steel shear walls, brace frames, buckling-restrained brace frames 鈥� a whole bunch of things you can do that, depending on your building, will work,鈥� she said.

Engineering studies indicated that the Public Services Building’s structural frame and internal components would fail in a sizable seismic event. And because county officials wanted a retrofit that would impact the building’s exterior appearance as little as possible, Epstein said, a final design was chosen that would involve placing a formidable series of concrete shear walls on each of the building’s corners. Each shear wall would then be tied into the building’s framework with a robust series of drag struts and other steel connectors.

Not only did this type of exterior-based solution allow the building to be used during construction, it eliminated the need to drill through and possibly compromise any of the post-tensioned concrete slabs.

鈥淚t just limits the amount of mechanical systems that are disrupted and how much ceiling you have to take down,鈥� KPFF Consulting Engineers principal Mark Tobin said. 鈥淚t really minimized how much other stuff was impacted with the structural elements, and it kept the new foundation on the outside of the building, as we were digging down anyway for the water issue. It was great not to have to cut through the basement slab.鈥�

Plus, this solution minimized any changes to the building’s appearance.

鈥淚t looks like it was part of the building originally,鈥� Epstein said. 鈥淎nd that was a concern of the commissioners.鈥�

The method also allowed the county to fix the water intrusion issue in the building’s foundation at the same time.

鈥淏y putting those concrete frames or shear walls on the outside of the building, we had to pull away the dirt to waterproof the building, so it was a two-for-one,鈥� Epstein said.

At the job site in Hillsboro, Khalifeh explained how the project is being completed in two phases in order to allow the county to continue to use at least one of the two building wings at all times.

Currently, work on the larger north wing is approaching its final stages as contractors refurbish the interior. The new reinforced concrete shear walls are evident at each building corner.

The former front lawn is now a gaping pit on either side of the main walkway leading to the entrance. At the bottom sits a pair of new water pumps designed to remove groundwater and prevent it from infiltrating the basement as in the past.

鈥淲e wanted to get the water away from the building, so we excavated all the way down and added windows in the basement,鈥� Khalifeh said. 鈥淪o what you see outside, that’s what it’s going to be 鈥� the de-watering wells, or pumping stations, in four locations and one inside the building.鈥�

The water intrusion issue could be addressed via the engineering solutions proposed for the seismic retrofit, Tobin said.

鈥淭here was some synergy between those two efforts,鈥� he said. 鈥淲e had to dig down, and they had to be at the basement level anyway. You can’t put a basement wall at ground level, so we had to dig down to get to the bottom of the slab to put in our footings and realized, 鈥楬ey, we’re getting a twofer here.’ That was a nice little bonus for the project.鈥�

As the work progressed, Tobin added, the resulting shear walls added to the building’s aesthetic.

鈥淚 think the unique aspect on this one is they’ve left the shear walls exposed,鈥� he said. 鈥淵ou see it from the outside and you can tell something was done, and it was robust and intentional. A lot of times when we do retrofits the architect’s goal is to hide it somewhere. 鈥� This was a little unique in that by placing it outside the building and making it concrete, it ties into other elements.鈥�

Crews are expected to complete the retrofit of the Public Services Building later this year.