Stress-Ribbon Footbridge over Fish Creek in Calgary, CA

(Satellite, I started searching for the bridge at the mouth of Fish Creek so I found quite a few footbridges before I found this one.)

Trail View, Sep 2023

Tanweer Malik posted four photos with the comment: "Stress-ribbon bridges over Fish Creek in Calgary, Canada."

Steve William Lindsey: I feel uncomfortable just looking at it. Doesn't inspire confidence like the Baxter wooden truss bridge in BC, to be demolished tomorrow.

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Tanweer Malik also posted these photos on linked with the comment:

Stress-ribbon bridges over Fish Creek in Calgary. 

“A stress ribbon bridge is a catenary structure in which tightly tensioned cables are embedded within a concrete (or other suitable materials) deck providing a form that allows the deck to be directly loaded (Ref: CSA S7:23 - Pedestrian, cycling, and multiuse bridge design guideline)”.

Unlike girder or truss bridges that typically have an upward camber in the middle to offset the downward deflection, these Stress-ribbon bridges have a funicular profile (due to the hidden cables) with a sag in the middle. The deck is fixed to the abutments.

Sergio Marletta: well well well, the MAIN issue with this type of bridge is psychology. Somehow the brain does not like negative cambers beyond 1/250 of the span. A normal user of the bridge will not understand that the visible camber is required for statics, a normal user might look for another way to cross. Also sensitivity to asymmetric loading will require a very low q/g ratio. Also as highlighted already, there is the horizontal pull on the abutments, making them expensive. Finally high temperature will reduce the clearance below deck. You see it is kinda more negatives than positives. 

Dr. Andreas Felber, P. Eng: They are not suited for heavy loaded vehicles.

"In June 2005 a flood destroyed or heavily damaged 9 of 15 pedestrian structures in Fish Creek Park and also rendered most of the park's pathways destroyed or damaged which made large portions of the park unusable to the public. In December 2005 Stantec Consulting Ltd. was engaged by Alberta Community Development to assess the damage and to develop a strategy to restore the park. During the reorganization of the pathway system the need for 4 new bridges was identified, which needed to be durable, resistant to floods, low in maintenance, and constructible in an environmentally sensitive area. A Stress-Ribbon Bridge was identified to be a suitable bridge type for these criteria. The presentation will concentrate on the design and construction challenges of this bridge type." [ucalgary]

Someone in Canada must like stress-ribbon bridges because there is another one in Edmonton.