Revolving bridge
On page 855 of the Atlantic Codex, are present three solutions for a revolving bridge for military purposes.
One of these was realized and it is formed by a supporting structure made of poles encaged by reticular, hemp ropes.
At the two ends there are some guide rollers (only sketched) while the bridge rotates around a single shaft. 400 years later the achievements of steel ropes will enable engineers-architects to realize bridge structures similar to Leonardo’s.
Bridge trusses
In an important but not well known medieval notebook, we can see, in the 33 pages left, V. de Honnecourt ‘s series of
technical drawings among which there are a hydraulic saw, an automat, a lugger and a wood bridge with reticular beams
( see model above)
It is an innovative idea that anticipates the Renaissance mbridge-making technique which includes Leonardo’s projects
and the four wooden bridges by Andrea Palladio. mIt is surprising how the Middle Ages considered an obscure and static historical period gave birth to people, among whom Hannecourt and Ruggero Bacone, who projected themes later developed during the Renaissance and in the modern era.
Self supporting bridge
This is the best known bridge, among the tens of bridges Leonardo designed, and it is remarkable for the genial structure and the (apparent) simplicity of its setting. The basic idea is for a military bridge to be built with wood on the spot and in a short time, thus, easily set up but also easily destroyed in case of need.
It is composed of a series of elements, mainly two modules, which duly embedded form the bridge; the bridge collapses if one single module is dislodged.
The assembling of the bridge requires some bracing to be removed when the work is completed.
