Rockfall catchment fences have a long history, with their beginnings being rooted in rigid structures. Building upon experience, mitigation structures became increasingly more flexible. Eventually the modern rockfall catchment fence was born, consisting of steel posts, continuous bearing ropes that support a flexible net structure and brake elements. Early brake elements primarily functioned by absorbing energy during an impact through friction. Support cables were lead through steel plates with several holes drilled in them. Another example of early brake elements utilized the deformation of steel to absorb energy by leading support cables through steel tubes in the shape of a ring. As a force was exerted on the cable, it tightened the ring, ultimately pulling it into a knot. A further advancement removed the support ropes from the brake element entirely and relied on the deformation of steel, for example a coil of steel that uncoils as one end is held in position and the opposite is pulled or a strip of steel that is forced through a roller to make a bend at a defined angle (e.g. 180 degrees). The authors will present a new type of brake element that further relies on the properties of steel to absorb energy, but instead of focusing on friction or the deformation of a profile, it harnesses the controlled failure of steel.
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