Composite beams, trusses and arches from joined pieces
Members 'for pulling' and 'for supporting'; keyed joints, triangular girders and an arch
A page of structural-carpentry studies for building strong members out of many joined pieces. The first drawings are labelled 'for pulling' (tension) and another 'for supporting' (bearing), the pieces keyed together with joints that must each have three notches. Further sketches show a king-post truss with braces, a long girder built of paired triangular pieces, a triangular cross-section, and a stepped scarf-jointed beam; the final drawings give two ways of making an arch, or a door's hinge-post, out of separate pieces.
On this page
Members 'for pulling' and 'for supporting'
Leonardo sorts the timbers by the force they carry: two are labelled 'per tirare' (for pulling, i.e. tension) and a third 'per reggere' (for bearing, i.e. compression). The labels assign each piece of a built-up beam its structural role.
Truss and arch built of pieces
A king-post truss with diagonal braces spans between supports, and the last drawings show two ways of forming an arch, or the hinge-post of a door, out of separate pieces. Paired triangular pieces are joined into a long lattice girder.
Keyed joints with three notches
The pieces that make up the beam above are joined with interlocking joints; Leonardo notes that each one must be cut with three notches to lock securely. Two triangles are to be attached together and worked as one piece.
Clamp for drawing the joints tight
A screw clamp is drawn over the topmost beam, the tool that pulls the jointed pieces together as indicated by the 'for pulling' labels.