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POWER LIST: ENGINEERING

The city tasked Otak with converting this former void into a much-needed safe zone for bicyclists and pedestrians. Previously, the only way they could move through the area was on the shoulder of McLoughlin Boulevard or in one of its five lanes of busy traffic.

Now the Kronberg Park multi-use walkway connects the south side of Milwaukie with its downtown via a 1,100-foot-long path, a 340-foot-long bridge and a 60-foot-long bridge.

The project team faced many geotechnical hurdles. Challenge no. 1: The site is within the Willamette River Greenway, a habitat conservation area, and a floodplain, which in combination restricted the width of the path and added environmental requirements. Challenge no. 2: the site is along the southern shore of Kellogg Lake, where refuse piled up in the 1940s and ’50s.

Chuck Green, a consultant project manager for Otak, said the project was like peeling back the layers of an onion. The trail’s north end is in the dump area and the south end is in the floodplain. The team had to make sure the ground was solid enough to hold bridge connections and infrastructure.

Special adaptable footings for the structural columns were designed to go into the landfill area because there was no way of knowing where they were digging, Otak senior structural project manager Scott Nettleton said.

Then there was challenge no. 3: the land is affected by the Migratory Bird Treaty Act of 1918. If a migratory bird nests, it cannot be disturbed until its chicks have left – potentially delaying construction. So, before the migratory season began, potential nesting trees were removed from the site.

A $1.2 million Connect Oregon grant helped pay for the $2.1 million project, which was completed on time and within budget.