Bike and pedestrian boardwalk in Verzasca Valley, Tenero-Gordola | 2003
Steel design influenced by the “Ponte dei balzi”
Comuni di Gordola e Tenero-Contra
Blueoffice Architecture, Bellinzona
Giorgio Masotti, Bellinzona
Next to Verzasca river mouth in Lake Maggiore, a boardwalk links Tenero-Contra municipality bank to Gordola municipality bank.
The structure, that is situated on the bike and pedestrian path linking Bellinzona to Locarno, allows to pass the 120 m long, natural, Verzasca riverbed by.
The designer’s idea grows out of the site observation and interpretation. So the Lavertezzo’s “Ponte dei balzi” in Verzasca Valley has been the reference to the layout of the project, that was able to use steel and a few material too, thanks to a resolute and considerable structural engineering.
Total length: 120 m
Spans: 60 + 60 m
Flat arch width: 2.80 m total width, 2.50 m available width
Structure weight: approx. 150 ton
Substructure: deep foundations (pillars)
The flat arch is basically composed of a slightly bowed straight line, while the four arches are curved into space. The steel flat arch – centrally constituted by a main tubular section and by solid web shores linked to each other through some tapered beams – is linked to the arched load-bearing structure through divergent suspenders. A metal bracing system in the central area horizontally levels the structure off, while the footpath ground, composed of prefabricated concrete panels, reinforces the running surface.
The elements – flat arch and arches –had been mainly assembled in the workshop in order to minimize welds in the building site to improve quality and building time.
The boardwalk had to be part of C3 corrosion class according to ISO 12944 rule.
SA 2 ½ sandblasting was completed in the workshop, while the grinding about the deburring was finished in the building site. Moreover, a Duplex treatment was done to the railing. First a hot-dip galvanization, then the out-and-out surface treatment were made.
The boardwalk in Verzasca valley was undoubtedly an exciting project in many aspects and it was to be thought successful, as 2009 PrixMetall demonstrates. It is important to build, no-efforts, this kind of structures, so as to leave a tangible and well-proportioned trace in our region. This structure makes an impression on the pedestrian.