PROJECT DESCRIPTION
Studiofornalè handled the structural design of the consolidation intervention for this 17th-century beam located within a residential building and supporting a residential floor slab.
The beam, measuring 18×56 cm in cross-section, is composed of 3 trapezoidal wooden beams that work together through notches and metal wedges.
It is interesting to note that based on these early experiences with composite beams, the use of timber for large spans was progressively refined (see Leonardo in the 16th century, del Rosso in the 18th century) until the birth of modern glued laminated timber (1905 with the Hetzer patent).
The beam, 8.7 m in length, was fractured at a knot on the intrados near a wedge. This imperfection was likely the cause of the crack and the resulting flexural deformation of the beam, which reaches 15 cm (L/58).
METAL COUNTERBRACING
The planned intervention consists of installing a metal counterbracing system.
The vertical tube can rotate on the threaded ends like a jack which, after tensioning the bar system, lifts the beam through further rotation on the axis, closing the crack.
The static scheme of the beam changes; it is no longer subject to bending but is subjected to compressive stresses.
SYSTEM DESIGN
The installation of the system required the fabrication of custom components.
All metal components were made from high-strength steel; the forks and lock nuts were manufactured on a CNC machining center while the plates were plasma cut.
The installation of the system required numerous hours to achieve the correct tensioning and balancing of the system
