Page 24 - FY Annual Report 2017-18

THE BRIDGES OF

WASHINGTON COUNTY

Bridges connect people across the rivers and valleys of Washing-
ton County. Bridges are critical to the function of the road system
and also some of the most highly visible, enduring and complicated
pieces of County infrastructure.

“Every bridge is unique because every stream and river is unique,”
said Marla Vik, Senior Engineer. “With different geometries, soil
types, water flows, heights and floodplain levels to take into consid-
eration, you can’t create one design and use it like a cookie-cutter
to build other bridges. Each bridge is a puzzle to solve.”

Vik was the project manager for the Springhill Road bridge over a
Tualatin River overflow channel. The Springhill Road bridge and the
Timber Road bridge (over Gales Creek) were both replaced in FY
2017–18. One new bridge, Basalt Creek Parkway over the TriMet
WES train tracks, was also constructed in FY 2017–18. All three
bridges were designed to meet seismic requirements.

“Bridges are vulnerable in a major earthquake,” said Aaron Clod-
felter, Principal Engineer. “The ground, the water and the bridge
itself all contribute to seismic vulnerability.”

Clodfelter tracks and consolidates bridge information to guide the
maintenance and replacement schedules for the County's bridges.
Most bridges are inspected every two years. Those showing signs
of wear and tear are inspected annually. The County maximizes the
life span of bridges through regular maintenance. Weight limiting
a bridge can also extend its life, but that can cause problems for
freight and emergency vehicles.

Continued on page 23

Aaron Clodfelter, Principal Engineer; Marla Vik, Senior Engineer LUT Annual Report FY 2017–18 Partnering for the Future | 22