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This pedestrian and bicycle crossing allows users of the Iron Horse Trail, a 33mi trail in the San Francisco Bay Area, to safely cross over a busy eight-lane roadway. The bridge is the centrepiece of the sustainable Contra Costa Centre Transit Village, recognised as a successful demonstration of a transit-oriented development.
Bridge design and community engagement
As project manager and bridge designer, Arup engaged the community in an outreach programme to reach consensus on the bridge’s form and location. This included stakeholder meetings, a public design charrette, and an online survey for residents.
Arup was responsible for developing four design options during the planning phase and for the detailed design of the community-selected steel arch option. The firm conducted geotechnical, civil, utility relocation, and lighting design for the project.
As prime consultant, Arup retained sub-consultants for architectural design of bridge components, landscape design, and modifications to the traffic signals.
The design addresses the sites’ multiple physical constraints and the need to allow access to utilities and for future transit uses. To preserve a tree-lined country lane, the bridge alignment follows an elongated S-curve on the north side. This alignment, in combination with the unique foundation and bridge superstructure design, carefully nestles the structure between underground and overhead utilities.
The lighting design celebrates the unique form and structure of this civic landmark.
Bridge structure
The bridge structure is over 800ft long, with a main span of 240ft and a 10ft-wide path of travel.
The main span is supported with cable hangers from two independent steel arch ribs. The arch ribs are supported on a single pile foundation that minimises the foundation width, and they each incline away from the deck. This unique geometry, further accentuated by the curvature of the deck, creates a striking sculptural effect.
Award recognition
The Robert I. Schroder Overcrossing has received multiple awards. These inlcude the 2011 California Transportation Foundation Project of the Year, the 2011 California Greenways and Trails Association Project Construction Award, and the 2012 IDEAS2 award for innovation in structural steel design from the American Institute of Steel Construction.
