LAKE IDRO JETTIES
The Association of Municipalities of the Brescia side of Lake Garda and Lake Idro set up an “experimental service of integrated public transport, with buses and navigation lines” in Lake Idro area, limited to the spring and summer months. The project required the construction of landing areas for public service boats and the modal interchange between boats and means of road transport.
The jetties were to be made of steel and wood. This called for the involvement of Nord Zinc.
The realisation
Support posts and frames.
The support posts and the base frame were hot dip galvanized according to UNI EN ISO 1461. The installation was classified as corrosion class lm1, a code that identifies installations immersed in fresh water. The loss of zinc thickness, within this class, is approximately 15 microns per annum according to UNI EN ISO 1461, mainly due to electrolytic corrosion.
The poles were made using 12 mm thick tubes: the thickness of the zinc coating that is created on this manufactured product is normally at least 70 microns, even though, in actual fact, a thickness of approximately 200 microns is normally used. From these assumptions, the result is a protective alloy with a durability of approximately 13 years. This time limit could have been increased with the realisation of reinforced galvanising – i.e. increased thickness obtainable after SA 2 1/2 sandblasting to be performed before galvanising. However, the same result was obtained by installing sacrificial cathodes, so as to limit the effects of electrolytic corrosion.
Parapets
The parapets were treated with SISTEMA TRIPLEX®: the Nord Zinc protective system that exploits nanotechnology treatments, to boost the corrosion protection performance of hot-dip galvanising with the aesthetic powder coating finish, resulting in a total durability of about 40 years.
Profiles
As regards the design and construction of the parapets, the choice of the profiles focused on round products with no sharp edges: sharp edges are, in fact, the first trigger point for rust, and is strongly discouraged by UNI EN ISO 14713 that recommends surface preparation according to ISO 8503-1.
