30 November, 2009
(8 Votes, average: 4.50 of 5)
Loading ...Over the Thrift glacier tip in the Swiss Alps, this year, has been constructed a spectacular suspension bridge. The 170 meters long bridge describe a perfect catenary over a 100 meters above the glacier. The structural design of the bridge responds with simplicity to the extreme conditions of high mountain:, Minimum temperatures, Heavy snow, winds and not forgetting the vibrations caused by pedestrians crossing the void.
Bridge Trift
In this video from Swiss television, we can appreciate the difficulty of building the bridge. As usual in the construction of structures in the most inaccessible parts of the Alpine valleys, helicopters were used to hold the main structural cables. Once installed, a team of climbers were instructed to place the wood slats that make up the board.
The Trift bridge allows the hiker crossing over the glacier to feel part of the landscape. The lightness of the structure makes the bridge not to be an imposition to the environment, but on the contrary provides a unique opportunity to appreciate the strong wind, the cold of the glacier, and the fragility of the whole system.
Trift Bridge - Foto de bluebell7760
This bridge not only fulfils to perfection the role of uniting both sides, but it makes that transition an experience in its own. In the following video you can see the spectacular crossing.
We have already discussed in Frame and Form the importance of bracing, for example in the case of Man on wire. The need to stiffen the structures formed by cables is a problem not only technical but also aesthetic.
Bridge Trift - Arriostramientos
On the bridge of Trift the solution is to laterally brace the bridge board using cables attached to a family of guidewires placed below the pedestrians field of view. These main stays describe a parabola due to the traction provided by the secondary cables.
In the following video you can see clear braces on both sides of the board.
These cables significantly reduce the lateral oscillation caused by high winds in the valley while dampen vibrations caused by pedestrians avoiding dynamic problems and resonance.
Another great feature on this bridge are the Abutments. As shown in the picture below the abutments are very rigidly fixing the position of the upper and lower cables, therefore, reducing the bridge rotation . Steel profiles are used to transmit the horizontal forces generated by the wind while they serve to anchor the wires that form the railling of the footbridge.
Bridge Trift - Stirrups
The rock walls of the valley provides the necessary anchorage to resist the forces transmitted through the wires. The anchors are surprisingly simple and crude, easy to imagine the forces that resist. The anchorages are designed to minimize the eccentricities and transmit the forces as simple as possible.
Bridge Trift - Anchors
Credits:
Customer: KWO Grimselstrom
Designer: John parsons, Chur
Builder: X-Alpin
Location: Glacier Trift, Swiss Alps
Metadata
Hanging Bridges pros and cons of this type of bridge
Collection of Photos on Flickr Trift Bridge
Animation in Goolge earth Trift Bridge:
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Hello,
This bridge has amazed me. That's why I chose to make a brief presentation of a work we do in class, but need to know what efforts are supported by the cable guides are located under the wooden strips.
Hi,
Oriol
Hello Oriol,
I'm glad you like the bridge. A good approximation for calculating the tensile stresses in the lower cord Trift bridge is to assume that this is a catenary subject to its own weight (the bridge) and use overload (5 kN/m2).
In this sense the problem is identical to that describe in Man On Wire II.
The equation to use also can be found on Wikipedia Catenary.
Good luck with the job and you enjoy it.
Jorge