{{Short description|Member that transfers gravitational loads downward}} {{about|an architectural element|notion of structural engineering|Structural support}} thumb|A bridge design utilizes support elements (columns) and spanning elements (two orthogonal sets of beams) '''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,{{sfn|Ching|Onouye|Zuberbuhler|2014|p=vii}} for example, columns and load-bearing walls.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=2}} Along with horizontal spanning systems (like beams{{sfn|Ching|Onouye|Zuberbuhler|2014|p=43}}), vertical supports form the core of a building's structure, housing human activities and enabling the creation of habitable environments.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=vii}}
== Function == The primary function of a vertical support is to act as part of a structural system (a "stable assembly" that sustains architectural forms).{{sfn|Ching|Onouye|Zuberbuhler|2014|p=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.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=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.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=14}}
=== Human scale === 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.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=138}} As the unsupported height of columns and bearing walls increases, they must become thicker to maintain stability,{{sfn|Ching|Onouye|Zuberbuhler|2009|p=138}} which additionally influences the visual scale of the space.
== Structural behavior == Vertical supports must collect gravity loads from the horizontal spanning systems (trusses, beams, and slabs) and redirect them downward.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=142}}
=== Load distribution === 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.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=142}} In a regular structural grid: * ''Interior columns'': carry the gravity loads for one full bay (extending halfway to the nearest column in all directions).{{sfn|Ching|Onouye|Zuberbuhler|2009|p=142}} * ''Perimeter columns'': carry approximately one-half the load of an interior column.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=142}} * ''Corner columns'': carry approximately a quarter of the load of an interior column.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=142}}
Skipping a column in the grid transfers its load to adjacent supports.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=142}} In multistory buildings, the gravity loads add up as they are transmitted downward through successive floors to the foundation.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=143}}
== Development and types == The form and material of vertical supports have evolved significantly throughout history, transitioning from massive elements to lighter skeletal frames.{{sfn|Ching|Onouye|Zuberbuhler|2014|pp=6-7}}
=== Stone and masonry === Early vertical supports were characterized by high mass: * Pillars and columns: Neolithic structures, such as those in Banpo, China (c. 5000 BC), utilized thick pillars to support roofs.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=2}} The Egyptians mastered trabeated (post-and-lintel) stone construction, exemplified by the Hypostyle Hall at Karnak (1500 BC).{{sfn|Ching|Onouye|Zuberbuhler|2014|p=3}} Ancient Greeks perfected the system, with the Parthenon (447 BC) representing the pinnacle of the Doric order in column design.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=4}} * Bearing walls: Until the late-18th century, stone and masonry bearing wall systems came to dominate the vertical support designs.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=16}} These systems simultaneously provided support and enclosure, with formal modifications limited to molding or carving the material mass.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=16}}
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.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=141}}
=== Timber, iron, and steel === The Industrial Revolution introduced high-strength materials that allowed vertical supports to become slender skeletal elements rather than massive walls:{{sfn|Ching|Onouye|Zuberbuhler|2014|p=7}} Unlike timber frames, the rigid steel and reinforced concrete designs might get away with no diagonal bracing or shear planes to ensure lateral stability.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=141}} * Cast iron frame: By 1797, Ditherington Flax Mill utilized a structural frame of cast iron columns and beams, becoming the world's first iron-framed building.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=8}} * Steel frames: The Home Insurance Building (1884) utilized a 10-story frame of steel and cast iron to carry the majority of the weight of floors and walls, reducing the reliance on masonry for support.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=10}} Steel frames may utilize moment connections for rigidity but require fireproofing to qualify as fire-resistive construction.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=141}}
=== Concrete === Vertical supports in reinforced concrete have allowed for diverse structural expressions. Concrete frames are typically rigid and qualify as noncombustible construction.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=141}} * Pillars: Modern suspension structures, such as the Olympic Arena in Tokyo (1961), utilize reinforced concrete pillars to anchor steel cables.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=12}} * Ribs: The Sydney Opera House (1973) utilizes precast concrete ribs to form its iconic shell structure.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=13}}
== Geometric and advanced support structures == In the field of architectural geometry, complex freeform designs require support structures that address the geometric complexity of nodes where multiple beams intersect.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}}
=== Torsion-free supports === In large-scale steel gridshells, the connection of beams at a vertex can introduce significant torsion if not geometrically optimized.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} 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''.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} 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.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} This principle was utilized for the support structure of the Yas Hotel Abu Dhabi.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}}
=== Parallel meshes and offsets === Torsion-free support structures can be derived from parallel meshes (also known as offset meshes).{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} 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.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} 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.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}}
=== Semidiscrete supports === For structures requiring curved members, the concept of a support structure can be refined through a limit process into a ''semidiscrete support structure''.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} 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.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} This technique was applied to the pavilions at the Eiffel Tower, where the beams follow the principal curvature lines of the reference surface.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}}
=== Tensegrity === {{main|Tensegrity}} 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).{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} This separation allows for lightweight support structures where distinct elements handle specific forces—cables allowing only tension and struts allowing only compression.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}} The Kurilpa Bridge (2009) is cited as a notable example, being the largest tensegrity bridge in the world.{{sfn|Pottmann|Eigensatz|Vaxman|Wallner|2015}}
== Spatial relationship == The pattern of vertical supports is intrinsically linked to the spatial composition of a design.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=20}} Because columns and walls have a greater presence in the visual field than horizontal planes, they are instrumental in defining volumes of space.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=140}} * ''Columns'': A structural frame of columns and beams allows for relationships to be established with adjacent spaces on all four sides of the defined volume.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=140}} * ''Bearing walls'': Using parallel bearing walls creates a directional quality, orienting the space toward open ends. If a space is enclosed on all four sides by bearing walls, it becomes introverted and must rely on openings for connection to adjacent spaces.{{sfn|Ching|Onouye|Zuberbuhler|2009|p=140}}
The structural/spatial relationship can be approached in two different ways: * ''Correspondence between structural and spatial arrangements'': The pattern of supports prescribes the disposition of spaces, or conversely, the spatial requirements dictate the structural rhythm.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=20}} * ''Flexibility'': The structural form is designed as a "looser fit," allowing freedom in the interior spatial layout independent of the vertical supports.{{sfn|Ching|Onouye|Zuberbuhler|2014|p=20}}
== References == {{reflist}}
== Sources == * {{cite book |last1=Ching |first1=Francis D.K. |last2=Onouye |first2=Barry |last3=Zuberbuhler |first3=Douglas |title=Building Structures Illustrated: Patterns, Systems, and Design |edition=1st |year=2009 |publisher=John Wiley & Sons |isbn=978-0470187852 | url=https://archive.org/details/buildingstructur0000chin}} * {{cite book |last1=Ching |first1=Francis D.K. |last2=Onouye |first2=Barry |last3=Zuberbuhler |first3=Douglas |title=Building Structures Illustrated: Patterns, Systems, and Design |edition=2nd |year=2014 |publisher=John Wiley & Sons |isbn=978-1-118-45835-8}} * {{cite journal |last1=Pottmann |first1=Helmut |last2=Eigensatz |first2=Michael |last3=Vaxman |first3=Amir |last4=Wallner |first4=Johannes |title=Architectural geometry |journal=Computers & Graphics |volume=47 |pages=145–164 |year=2015 |doi=10.1016/j.cag.2014.11.002 | url=https://repository.kaust.edu.sa/bitstream/handle/10754/555976/survey-final.pdf?sequence=2}}
Category:Structural system Category:Architectural elements Category:Columns and entablature