Excerpt:
Welcome to the Portland Bridges page, presented by Environmental Services, Oregon Department of Transportation. The bridges of Portland, Oregon are numerous and diverse. The structures, ranging in age from 27 years to 90 years of age, represent a variety of construction types including vertical lift spans, double-leaf Bascule drawspans, and the longest tied arch span in the world.
Annotation:
History and discussion on Modjeski's proposal for a bascule construction.