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, for example, columns and load-bearing walls. Along with horizontal spanning systems (like beams), vertical supports form the core of a building's structure, housing human activities and enabling the creation of habitable environments.
The primary function of a vertical support is to act as part of a structural system (a "stable assembly" that sustains architectural forms). 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.
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.
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. As the unsupported height of columns and bearing walls increases, they must become thicker to maintain stability, 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.
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. In a regular structural grid:
Skipping a column in the grid transfers its load to adjacent supports. In multistory buildings, the gravity loads add up as they are transmitted downward through successive floors to the foundation.
The form and material of vertical supports have evolved significantly throughout history, transitioning from massive elements to lighter skeletal frames.
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.
The Industrial Revolution introduced high-strength materials that allowed vertical supports to become slender skeletal elements rather than massive walls: Unlike timber frames, the rigid steel and reinforced concrete designs might get away with no diagonal bracing or shear planes to ensure lateral stability.
Vertical supports in reinforced concrete have allowed for diverse structural expressions. Concrete frames are typically rigid and qualify as noncombustible construction.
In the field of architectural geometry, complex freeform designs require support structures that address the geometric complexity of nodes where multiple beams intersect.
In large-scale steel gridshells, the connection of beams at a vertex can introduce significant torsion if not geometrically optimized. 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. 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. This principle was utilized for the support structure of the Yas Hotel Abu Dhabi.
Torsion-free support structures can be derived from parallel meshes (also known as offset meshes). 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. 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.
For structures requiring curved members, the concept of a support structure can be refined through a limit process into a semidiscrete support structure. 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. This technique was applied to the pavilions at the Eiffel Tower, where the beams follow the principal curvature lines of the reference surface.
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). This separation allows for lightweight support structures where distinct elements handle specific forcesâÂÂcables allowing only tension and struts allowing only compression. The Kurilpa Bridge (2009) is cited as a notable example, being the largest tensegrity bridge in the world.
The pattern of vertical supports is intrinsically linked to the spatial composition of a design. Because columns and walls have a greater presence in the visual field than horizontal planes, they are instrumental in defining volumes of space.
The structural/spatial relationship can be approached in two different ways: