Old Lorzentobel bridge

Initial situation and concept

The old Lorzentobel bridge is a 112-year-old natural stone arch bridge in the canton of Zug. The arch viaduct (second tobel bridge) is used by pedestrians and cyclists and provides access to the adjacent forest areas for forestry purposes. It spans the deeply incised Lorze Gorge, the Lorzentobel. The historic bridge was renovated with federal funding until May 2025.

As part of the renovation, Jakob Rope Systems developed a passive safety solution using vertical Webnet structures made of stainless steel ropes. The transparent mesh structure ensures safety while having a minimal visual impact on the historic structure.

Construction and implementation

Jakob Rope Systems handled the engineering and design of the vertical net and rope structures. Webnet elements with a 2-millimeter rope diameter and 70-millimeter mesh size were used, along with spectrally colored surround ropes (16-millimeter rope diameter).

The total safety area of 856 square meters was divided into 110 prefabricated individual net segments for assembly and manufactured to exact specifications at the factory. The installation of the vertical Webnet safety system took place on-site in January and February 2025, enabling efficient implementation with minimal impact on the existing building structure.