During the renovation of the dam, 674 meters of special railings made from perforated sheets supplied by SCHÄFER Perforated Metal were installed on the dam wall to ensure permanent terrain stabilization.
The original fall protection consisted of tubular railings that no longer met contemporary safety standards for a publicly accessible area. Children could climb on them or even squeeze through, and the required minimum height of 1.10 meters was not met. For this reason, Kraftwerke Linth-Limmern AG (KLL) commissioned REECH, a Swiss full-service provider for photovoltaic systems, storage systems, and electric charging stations, to design and implement a fall protection system that complies with modern standards.
"When designing the fall protection, various design variants were evaluated, calculated and visualised. The perforated sheet variant was ultimately preferred to the alternative wire mesh solution because it meant that a more attractive appearance could be achieved at a manageable additional cost and, in addition, significantly less installation work was to be expected on-site," explains Tamás Szacsvay, Managing Partner at REECH AG, responsible for design and planning.
The existing posts and crossbars, made of hot-dip galvanized steel, could be rehabilitated on both the lake and valley sides to firmly anchor the individual perforated sheet elements. This approach received the most support as a sustainable and cost-effective solution.
KLL conducted on-site tests with prototype samples to verify that the desired results were achieved, especially at locations with varying wall curvatures. Subsequently, the perforated sheet elements (perforation RV20-30) from SCHÄFER Perforated Metal were produced, folded, packaged, and cut to size with minor optimizations and the required precision.
The elements had a uniform height of 1,150 millimeters when assembled. However, due to non-uniform post spacing, twelve different element lengths had to be considered in varying quantities. Standard production was not feasible.
"Due to the high alpine location and the requirements for corrosion protection, the manufactured individual elements are made of factory pre-anodised three millimetre thick aluminium sheet with a double layer thickness of 20 micrometres," says Eric Diehl, project manager in technical sales at SCHÄFER Perforated Metal.
The reinforced anodizing process creates a protective oxide layer on the aluminum surface, safeguarding it against corrosion. This significantly extends the durability and lifespan of the aluminum perforated sheets, particularly in environments with high humidity or exposure to aggressive chemicals.
"We have been searching for a long time for a suitable material that can permanently withstand the harsh conditions in winter during storms and rain. For this reason, we decided to use perforated sheets. As visitors tour the dam, the aesthetic appearance was also important to us. So far we have only received positive feedback," says Peter Schindler, Technical Assistant Mechanics at Kraftwerke Linth-Limmern AG.
Operating under the motto "Custom Perforated Sheets - Made to Measure, Individually, and Promptly," SCHÄFER Perforated Metal offers a wide selection of high-quality perforated sheets for various industries and diverse applications, with immediate availability. TECmetall GmbH in Würenlos, a long-standing distribution partner, ensures customer proximity and provides expert advice on perforated sheets in the Swiss market.
