Structural Challenges in the Design of Three Pedestrian Bridges

This paper describes design aspects of three pedestrian bridges that were recently completed: the main bridge of the San Ysidro East/West Pedestrian Bridge in San Diego, CA, the Blossom Hill Pedestrian Grade Separation Bridge in San Jose, CA, and the Montlake Bicycle/Pedestrian Bridge in Seattle, WA. The 806’-6”-long main bridge of the San Ysidro East/West Pedestrian Bridge over I-5 freeway consists of a cast-in-place prestressed concrete box girder superstructure supported by highly skewed pier walls with pile foundation. The 314’-6”-long Blossom Hill Pedestrian Bridge across the SR 82/UPPR Corridor is a two span continuous structural steel tube truss bridge with an overall structure depth of 12’-0”. The 427-foot-long Montlake Triangle Pedestrian (MTP) Bridge structure spans Montlake Boulevard near the University of Washington campus. The MTP Bridge is one of the first applications of a highly curved post-tensioning concrete structure in the United States. All of these pedestrian bridges were designed by AECOM. The specific structural challenges in design for these structures will be discussed herein.