Most of the bridges drawn by Leonardo
date to the first years after his arrival in Milan
in 1482. The Self-Supporting Bridge is certainly the
most ingenious for its constructive and structural
simplicity. It is in fact a structure made of simple
circular-section beams to be assembled without the use of
fastenings or interlocking joints. Once assembled, the bridge’s
weight must be sufficient to exert the
necessary pressure so that the longitudinal beams can block
the transversal ones in place by closing like a pair
of scissors, thus preventing the structure from
collapsing. The greater the pressure on the upper part
of the bridge, the greater its stability.
Machines
Self-supporting bridge
Codex Atlanticus, folios 69ar, 71v (1487-1489)