Vertical support is a category of structural systems or elements in architecture and architectural engineering designed to facilitate the vertical dimensions of space and mass, [1] for example, columns. [2] Along with horizontal spanning systems (like beams [3] ), vertical supports form the core of a building's structure, housing human activities and enabling the creation of habitable environments. [1]
The primary function of a vertical support is to act as part of a structural system (a "stable assembly" that sustains architectural forms). [2] As a fundamental component of a structural system, it is responsible for supporting and transmitting applied loads (such as gravity, wind, and earthquake forces) safely to the ground without exceeding the allowable stresses in the members. [2]
In the context of architectural design, vertical supports function similarly to a skeletal system in a body; they give shape and form to the building while providing support for other building systems and organs. [4]
Vertical supports are instrumental in establishing the scale of a building's interior. Of the three dimensions of a room, height has a greater impact on perceived scale than width or length; a ceiling height that feels comfortable in a smaller room may feel oppressive in a large assembly space. [5] As the unsupported height of columns and bearing walls increases, they must become thicker to maintain stability, [5] which additionally influences the visual scale of the space.
Vertical supports must collect gravity loads from the horizontal spanning systems (trusses, beams, and slabs) and redirect them downward. [6]
The load imposed on a specific vertical support is determined by its tributary area, which corresponds to the span of the floor or roof structure it carries. [6] In a regular structural grid:
Skipping a column in the grid transfers its load to adjacent supports. [6] In multistory buildings, the gravity loads add up as they are transmitted downward through successive floors to the foundation. [7]
The form and material of vertical supports have evolved significantly throughout history, transitioning from massive elements to lighter skeletal frames. [8]
Early vertical supports were characterized by high mass:
Concrete and masonry walls rely on their bulk for load-carrying capability and can withstand high compression forces, but require reinforcement to resist the tensile stresses. [12]
The Industrial Revolution introduced high-strength materials that allowed vertical supports to become slender skeletal elements rather than massive walls: [13] Unlike timber frames, the rigid steel and reinforced concrete designs might get away with no diagonal bracing or shear planes to ensure lateral stability. [12]
Vertical supports in reinforced concrete have allowed for diverse structural expressions. Concrete frames are typically rigid and qualify as noncombustible construction. [12]
In the field of architectural geometry, complex freeform designs require support structures that address the geometric complexity of nodes where multiple beams intersect. [18]
In large-scale steel gridshells, the connection of beams at a vertex can introduce significant torsion if not geometrically optimized. [18] A torsion-free support structure is defined geometrically as an arrangement of planar quadrilaterals along the edges of a mesh such that all quadrilaterals meeting at a vertex intersect in a single common line, known as the node axis. [18] When structural beams are aligned with these quadrilaterals, their symmetry planes pass through the node axis, creating a torsion-free node that is significantly easier to manufacture than a general node. [18] This principle was utilized for the support structure of the Yas Hotel Abu Dhabi. [18]
Torsion-free support structures can be derived from parallel meshes (also known as offset meshes). [18] Two meshes are considered parallel if they share the same combinatorics and their corresponding edges are parallel; the beam structure effectively connects these two layers. [18] A special case is the conical mesh, where the parallel meshes are at a constant face-to-face distance, allowing for the use of node axes that coincide with the axes of the cones associated with the mesh vertices. [18]
For structures requiring curved members, the concept of a support structure can be refined through a limit process into a semidiscrete support structure. [18] This results in support members that form developable strips, which allows for the fabrication of curved beams with rectangular cross-sections by bending flat material rather than complex molding or machining. [18] This technique was applied to the pavilions at the Eiffel Tower, where the beams follow the principal curvature lines of the reference surface. [18]
Tensegrity, a term coined by Buckminster Fuller in 1960, refers to structural systems composed of isolated components under compression (struts) inside a continuous net of tension (cables). [18] This separation allows for lightweight support structures where distinct elements handle specific forces—cables allowing only tension and struts allowing only compression. [18] The Kurilpa Bridge (2009) is cited as a notable example, being the largest tensegrity bridge in the world. [18]
The pattern of vertical supports is intrinsically linked to the spatial composition of a design. [19] Because columns and walls have a greater presence in the visual field than horizontal planes, they are instrumental in defining volumes of space. [20]
The structural/spatial relationship can be approached in two different ways: