Tensioned stone

Southwark Gateway Needle, a post-tensioned stone structure.

Tensioned stone is a high-performance composite construction material: stone held in compression with tension elements. The tension elements can be connected to the outside of the stone, but more typically tendons are threaded internally through a drilled duct.

Tensioned stone can consist of a single block of stone, though drill limitations and other considerations mean it is typically an assembly of multiple blocks with grout between pieces.[1] Tensioned stone has been used in both vertical columns (posts), and in horizontal beams (lintels). It has also been used in more unusual stonemasonry applications: arch stabilization, foot bridges, granite flag posts, cantilevered sculptures, a space frame, and staircases.

Tensioned stone has an affiliation with massive precut stone, which is a central technique of modern load-bearing stonemasonry. It is also aligned with mass timber and straw structural insulated panels (SSIPs), which are all reconfigurations of traditional materials for modern construction.[2][3]