Flying buttress

Theflying buttress(arc-boutant,arch buttress) is a specific form ofbuttresscomposed of an arch that extends from the upper portion of a wall to a pier of great mass, in order to convey to the ground the lateral forces that push a wall outwards, which are forces that arise fromvaultedceilings of stone and from wind-loading on roofs.^[1]

The namesake and defining feature of a flying buttress is that it is not in contact with the wall at ground level, unlike a traditional buttress, and transmits the lateral forces across the span of intervening space between the wall and the pier. To provide lateral support, flying-buttress systems are composed of two parts: (i) a massivepier,a vertical block of masonry situated away from the building wall, and (ii) anarchthat bridges the span between the pier and the wall – either a segmental arch or a quadrant arch – theflyerof the flying buttress.^[2]

History

The 4th-centuryRotunda of GaleriusinThessaloniki,Greece, showing an early example of flying buttresses

As a lateral-support system, the flying buttress was developed duringlate antiquityand later flourished during theGothic period(12th–16th c.) of architecture. Ancient examples of the flying buttress can be found on theBasilica of San Vitalein Ravenna and on theRotunda of Galeriusin Thessaloniki. The architectural-element precursors of the medieval flying buttress derive fromByzantine architectureandRomanesque architecture,in the design of churches, such asDurham Cathedral,where arches transmit the lateral thrust of the stone vault over the aisles; the arches were hidden under the gallery roof, and transmitted the lateral forces to the massive, outer walls. By the decade of 1160, architects in theÎle-de-Franceregion employed similar lateral-support systems that featured longer arches of finer design, which run from the outer surface of the clerestory wall, over the roof of the side aisles (hence the visibility from the outside) to meet a heavy, vertical buttress rising above the top of the outer wall.^[3]

The flying buttresses ofNotre Dame de Paris,constructed in 1180, were among the earliest to be used in a Gothic cathedral. Flying buttresses were also used at about the same time to support the upper walls of the apse at theChurch of Saint-Germain-des-Prés,completed in 1163.^[4]

Flying buttress ofReims Cathedral,as drawn byVillard de Honnecourt

The advantage of such lateral-support systems is that the outer walls do not have to be massive and heavy in order to resist the lateral-force thrusts of the vault. Instead, the wall surface could be reduced (allowing for larger windows, often glazed with stained glass) because the vertical mass is concentrated onto external buttresses. The design of early flying buttresses tended to be heavier than required for the static loads to be borne, e.g. atChartres Cathedral(ca. 1210), and around theapseof theSaint Remi Basilica,which is an extant, early example in its original form (ca. 1170).^[5]Later architects progressively refined the design of the flying buttress, and narrowed the flyers, some of which were constructed with one thickness ofvoussoir(wedge brick) with a capping stone atop, e.g. atAmiens Cathedral,Le Mans Cathedral,andBeauvais Cathedral.

The architectural design of Late Gothic buildings featured flying buttresses, some of which included flyers decorated withcrockets(hooked decorations) and sculpted figures set inaedicules(niches) recessed into the buttresses.

The architecture of the Renaissance eschewed the lateral support of the flying buttress in favour of thick-wall construction. Despite its disuse for function and style in construction and architecture, in the early 20th century, the flying-buttress design was revived by Canadian engineerWilliam P. Andersonto buildlighthouses.^[6]

Construction

Architectural drawing of aNeo-Gothicflying buttress for the late 19th-centuryVotive Church,in Vienna

A flying buttress as remedial support for a church wall in the English village ofChaddesley Corbett(note the traditional buttress in the foreground)

Given that most of the weight-load is transmitted from the ceiling through the upper part of the walls, the flying buttress is a two-part composite support that features a semi-arch that extends to a massive pier far from the wall, and provides most of theload-bearing capacityof a traditional buttress, which is engaged with the wall from top to bottom; thus, the flying buttress is a lighter and more cost-effective architectural structure.

By relieving theload-bearing wallsof excess weight and thickness, in the way of a smaller area of contact, using flying buttresses enables installing windows in a greater wall surface area. This feature and a desire to let in more light, led to flying buttresses becoming one of the defining factors of medieval Gothic architecture and a feature used extensively in the design of churches from then and onwards. In the design of Gothic churches, two arched flyers were applied, one above the other, in which the lower flyer (positioned below the springing point of the vault) resists the lateral-thrust forces of the vault, whilst the upper flyer resists the forces of wind-loading on the roof.^[7]The vertical buttresses (piers) at the outer end of the flyers usually were capped with apinnacle(either a cone or a pyramid) usually ornamented with crockets, to provide additional vertical-load support with which to resist the lateral thrust conveyed by the flyer.^[8]

To build the flying buttress, it was first necessary to construct temporary wooden frames, which are calledcentring.The centering would support the weight of the stones and help maintain the shape of the arch until themortarwas cured. The centering was first built on the ground, by the carpenters. Once that was done, they would be hoisted into place and fastened to the piers at the end of one buttress and at the other. These acted as temporary flying buttresses until the actual, stone arch was complete.^[9]

Remedial support application

Another application of the flying-buttress support system is the reinforcement of a leaning wall in danger of collapsing, especially a load-bearing wall; for example, at the village ofChaddesley CorbettinWorcestershire,England, the practical application of a flying buttress to a buckled wall was more practical than dismantling and rebuilding the wall.

Aesthetic style of the Gothic period

The early-Gothic Notre-Dame de Paris (shown here with buttresses as later modified) features flying buttresses with blocky porticoedpinnacles,surrounding a tall nave, aclerestory,a widetriforium,and twoside aisles.Arrows show structural forces (details).

The need to build large cathedrals that could house many people along multipleaislesprovided the stimulus for theGothicstyle to be developed.^[10]The flying buttress was the solution to these massive stone buildings that needed additional support. Although the flying buttress originally served a structural purpose, they are now a staple in the aesthetic style of theGothic period.^[11]The flying buttress originally helped bring the idea of open space and light to the cathedrals through stability and structure, by supporting theclerestoryand the weight of the high roofs.^[11]The height of the cathedrals and amply sized windows among the clerestory creates an open space giving the illusion of no clear boundaries.^[11]

It also makes the space more dynamic and less static separating theGothicstyle from the flatter, more two dimensional,Romanesquestyle.^[11]After the introduction of the flying buttress this same concept could be seen on the exterior of the cathedrals as well.^[11]Open space below the arches of the flying buttress has the same effect as the clerestory within the church allowing the viewer to see through the arches. The buttresses also reach into the sky similar to thepillarswithin the church which creates more upward space,^[11]making the exterior space equally as dynamic as the interior space and creating a sense of coherence and continuity.^[12]

Gallery of flying buttresses

Notre-Dame de Paris
Notre Dame of Paris
One of the very ornate flying buttresses ofSt. John's Cathedral, 's-Hertogenbosch,The Netherlands
In the basilica built ca. AD 1170 at theAbbey of Saint-Remi,in France a flying buttress system is used for lateral-support
Saint Rose of Viterbo Church,Santiago de Querétaro,Querétaro, Mexico
Tower of St Peter and St Paul's Church,Easton Maudit,England
Lincoln Cathedral,England
Saint-Petrus-en-Pauluskerk,Ostend,Belgium
Bath Abbey,England
Cologne Cathedral,Germany
Washington National Cathedral,USA
Amiens Cathedral,Amiens, France
Manchester Unity BuildinginMelbourne,Australia
Flying buttresses in cross-section

In fiction

The architecture and construction of a medieval cathedral with flying buttresses figures prominently into the plot of the historical novelThe Pillars of the EarthbyKen Follett(1989).

Notes

^Curls, James Stevens, ed. (1999).A Dictionary of Architecture.Oxford. pp. 113–114.{{cite book}}:CS1 maint: location missing publisher (link)
^For the functional mechanics of the flying buttresses, seeBorg, Alan; Mark, Robert (1973). "Chartres Cathedral: A Reinterpretation of its Structure".The Art Bulletin.55(3): 367–372.doi:10.1080/00043079.1973.10790710.
^James, John (September 1992). "Evidence for flying buttresses before 1180".J. Soc. Archit. Hist.51(3): 261–287.doi:10.2307/990687.JSTOR 990687.
^Watkin, David, "A History of Western Architecture" (1986), page 130
^Prache, Anne (1976). "Les Arcs - boutants au XIIe siècle".Gesta.15(1): 31–42.doi:10.2307/766749.JSTOR 766749.S2CID 193417526.
^Rowlett, Russ."Canadian Flying Buttress Lighthouses".The Lighthouse Directory.University of North Carolina at Chapel Hill.
^Mark, R.; Jonash, R. S. (1970). "Wind Loads on Gothic Structures".Journal of the Society of Architectural Historians.29(3): 222–230.doi:10.2307/988611.JSTOR 988611.
^Curls, James Stevens, ed. (1999).A Dictionary of Architecture.Oxford. p. 501.
^Alex Lee, James Arndt, and Shane Goldmacher,Cathedral Architecture Archived2005-08-29 at theWayback Machine.
^Moore, Charles H. (1979).Development + & and character of gothic architecture.Longwood. pp.19-20.ISBN 0893413585.OCLC 632226040.
^^a ^b ^c ^d ^e ^fFrankl, Paul (1962).Gothic Architecture.Baltimore: Penguin Books. pp. 54–57.
^Mark, Robert (2014).Experiments in Gothic Structure.Bibliotheque McLean.ISBN 978-0955886867.OCLC 869186029.

References

Watkin, David (1986).A History of Western Architecture.Barrie and Jenkins.ISBN 0-7126-1279-3.

Chisholm, Hugh,ed. (1911)."Flying buttress".Encyclopædia Britannica.Vol. 10 (11th ed.). Cambridge University Press. p. 585.

[1] Curls, James Stevens, ed. (1999).A Dictionary of Architecture.Oxford. pp. 113–114.{{cite book}}:CS1 maint: location missing publisher (link)

[2] For the functional mechanics of the flying buttresses, seeBorg, Alan; Mark, Robert (1973). "Chartres Cathedral: A Reinterpretation of its Structure".The Art Bulletin.55(3): 367–372.doi:10.1080/00043079.1973.10790710.

[3] James, John (September 1992). "Evidence for flying buttresses before 1180".J. Soc. Archit. Hist.51(3): 261–287.doi:10.2307/990687.JSTOR 990687.

[4] Watkin, David, "A History of Western Architecture" (1986), page 130

[5] Prache, Anne (1976). "Les Arcs - boutants au XIIe siècle".Gesta.15(1): 31–42.doi:10.2307/766749.JSTOR 766749.S2CID 193417526.

[6] Rowlett, Russ."Canadian Flying Buttress Lighthouses".The Lighthouse Directory.University of North Carolina at Chapel Hill.

[7] Mark, R.; Jonash, R. S. (1970). "Wind Loads on Gothic Structures".Journal of the Society of Architectural Historians.29(3): 222–230.doi:10.2307/988611.JSTOR 988611.

[8] Curls, James Stevens, ed. (1999).A Dictionary of Architecture.Oxford. p. 501.

[9] Alex Lee, James Arndt, and Shane Goldmacher,Cathedral Architecture Archived2005-08-29 at theWayback Machine.

[10] Moore, Charles H. (1979).Development + & and character of gothic architecture.Longwood. pp.19-20.ISBN 0893413585.OCLC 632226040.

[:0-11] Frankl, Paul (1962).Gothic Architecture.Baltimore: Penguin Books. pp. 54–57.

[12] Mark, Robert (2014).Experiments in Gothic Structure.Bibliotheque McLean.ISBN 978-0955886867.OCLC 869186029.

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