Wednesday, October 22, 2014

Shasta County, California Bridges: Sacramento River Trail Bridge (3)

October 2014 (40.6015 Degrees, -122.4443 Degrees) Sacramento River Trail Bridge
Rather than the typical seat-type abutments found on most bridges, the Sacramento River Trail Bridge abutments helps carry the large tension force of the hanging bridge superstructure into the earth. The superstructure deepens as it approaches the abutments to separate the cables before they are anchored into the bedrock. The superstructure is composed of waffle slab segments with tapered edge elements carrying the barrier rail. I wonder if the cables are distributed across the deck or are concentrated along the sides?
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Shasta County, California Bridges: Sacramento River Trail Bridge (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Tuesday, October 21, 2014

Shasta County, California Bridges: Sacramento River Trail Bridge (2)

October 2014 (40.6015 Degrees, -122.4443 Degrees) Sacramento River Trail Bridge
Another view of the Sacramento River Trail (stressed-ribbon) Bridge. It was designed by Jiri Strasky, a Czech engineer who has built several of these bridges and has even written a book "Stress Ribbon and Cable-Supported Pedestrian Bridges" about them. However the concept of a catenary bridge is very old. Bridges made of ropes suspended over rivers were used by the Incas and Chinese for centuries. In the 1960s Leonel Viera designed the Maldonado Bridge in Uruguay by loading cables supporting precast segments with weights and then grouting the 'prestressed' structure together. 
Creative Commons License
Shasta County, California Bridges: Sacramento River Trail Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.