NE 90th Street Bridge

Redmond, WA, USA


Key Structural Engineer for the multiple award-winning landmark Northeast 90th Street Bridge over the Sammamish River for the City of Redmond, Washington State, USA. This 220-ft (67m) reinforced concrete box girder bridge is supported by leaning arches, was designed in cooperation with an architect, and uses 8,000 psi (55 MPa) concrete throughout.

Performed both static and seismic analysis of entire bridge structure using advanced analysis techniques such as shear-flexible grillage analysis and three-dimensional solid finite element analysis. Designed inclined reinforced concrete arches, abutments, reinforced concrete drilled-shaft foundation, steel cantilever sidewalk supports, and precast structural sidewalk panels. Performed extensive computer modeling of bridge, including graphical renderings to solve complex geometry issues. Also coordinated architectural elements with the project architect. Performed load rating of bridge. Finally, assisted with construction management and inspection of various phases of the bridge construction.

The NE 90th Street Bridge was awarded the following awards:

  • Gold Award for Engineering Excellence:  American Council of Engineering Companies, Washington (2002)
  • Northwest Construction Project of the Year:  American Public Works Association of Washington (2002)
  • Excellence in Concrete Construction, Grand Award (Best Overall):  Washington Aggregates and Concrete Association (2002)
  • Excellence in Concrete Construction, Artistic Merit:  Washington Aggregates and Concrete Association (2002)
  • Award of Excellence, Heavy Highway Category:  American General Contractors (2002)
  • Excellence in Structural Engineering, Merit Award:  National Council of Structural Engineers Associations (2002)
  • Honor Award for Civic Design:  American Institute of Architects, Washington Council (2001)
  • First Place Award, Heavy Construction Category:  American Society of Landscape Architects (2002)

Client: City of Redmond, Washington, USA
Engineer: Entranco
Architect: LMN Architects
Images: Entranco