Kantiléveres

Kantiléveres are structural elements that are fixed at one end and project horizontally or at a steep angle beyond their support, carrying loads without intermediate supports. They are used in architecture and civil engineering to create overhangs, balconies, canopies, and similar features, as well as in some bridge designs and crane structures. The key characteristic is that the projecting portion must be supported at its proximal end, while the free end carries loads.

In operation, cantilevers resist bending moments and shear along their length, with the maximum moment occurring at the fixed support. Common load cases include distributed loads and point loads at the free end. For a cantilever of length L with a uniform load w, the fixed-end bending moment is wL^2/2; with a point load P at the free end, the moment is PL. Deflection increases toward the end of the cantilever, and careful design is required to limit excessive sagging and vibrations.

Common forms include horizontal cantilever slabs or beams forming balconies and overhangs, as well as cantilever arms in cranes and jib systems. In structural engineering, cantilever bridges use anchored arms to balance loads across spans; the Forth Bridge in Scotland is a notable historic example of a large cantilever structure.

Materials typically used for kantiléveres are steel, reinforced concrete, or composite sections. Steel provides high strength and ductility, while reinforced concrete cantilevers rely on reinforcement and sometimes prestressing to resist tensile stresses. Design considerations include deflection limits, stability against tipping or buckling, torsion, and the detailing of the fixed connection to the supporting structure.