The arch form firstly evolved as a structural element that applied for underground
structures such as tunnels for drainage systems and foundations for buildings as early
as 4000BCE. But ever since the Romans adapted the arch, a new architectural
treatment was given to its form that not to mention its structural advantages,
applied for the design and elaboration of grand scale civic buildings and monuments
that would compromise with the tastes and predilections of the Empire’s noble
society. [ Jackson T.G. p 6 ]
Triumphal arches were highly elaborate structures erected to commemorate military
victory and important events such as the ‘capture of Jerusalem’ depicted in sculptures
in the Arch of Titus in Rome ( Figure 1 ). The arch form in this case is purely for
decoration as it features part of it on its underside (Figure 2 ) and simply connects
two pillars on which a superstructure rests. [He.S. p911]
Figure 1 Arch of Titus, Rome Figure 2 The underside of the Arch of Titus
Chiefly, the Romans had also proved their engineering skills through the procedure
concerning the construction of the arch and which is called centering ( Figure 3 ).
Stones cut in wedge shape known as voussoirs were laid on a temporary timber frame
that followed the underside of a semicircular or segmental arch. When the ring was
complete and centering had been removed, the maximum vertical load occurs at the
crown of the arch which is why a joint between two voussoirs was avoided at that
particular point. - 2 –
Figure 3 Figure 4
Centering ( Drawn by author ) Roman aqueduct at Pont du Gard, France
Therefore the keystone – which was the top most stone of the arch - resulted by using
an odd number of voussoirs. Thus, vertical loads spread radially causing an outward
push at the point where the arch abuts with its supports, from where the forces
continue a vertical route towards the foundations.
As a result, the tensile stresses that forced the lintel to snap convert into compressive
to which the arch resists bending downwards due to its curved shape.
Owing to this structural advantage, wide openings in structures could be spanned and
for the long distances of bridges and aqueducts the structure consists of a series of
arches ( Figure 4 ) – known as an arcade – resembling the former trabeated orders.
Throughout history the arcade was a very recurring type of structure as can bee seen
at one of the most most remarkable buildings of antiquity – the Colloseum in Rome –
following a circular plan at ground floor level and the next two stories above (
Figure 6 ).In this case, a reasonable compoarison is that between the two distinct types
of structure : The arcade, and post and lintel in trabeated order. While the narrow
intercolumniations prevent the spanning of wide openings , the ground floor arcade of
the Colloseum eliminates this problem with its eighty broad span arched entrances
that – in contribution with the efficient system of stairways and corridors ( Figure 5 ) –
– 3 -
benefit the amphitheatre by enabling quick clearance from about 50 000 spectators. [He. S. p 911]
Figure 5 Figure 6
System of corridors and stairways The Colosseum in Rome
Below the seating skin of the amphitheatre were constructed a system of extruded
arches known as vaults, serving as circulation passages. Naturally following the same
structural principal of the arch, these vaults provide structural support as they spring
above the summit of the arcade’s arches conducting the loads to the columns between.
This proves the arcades do not serve any load bearing purposes, but constitute the
decoration of the building by the sharp and contrasting effect of shadow and light,
produced by the shaded space behind the arcades and the illuminated façade.
It can be seen how the Romans were influenced by the Greek trabeated orders due to
Their frequent contacts from about 200BC [ He. S. p 913 ]. In advance, they contrived
to develop the arch also as space-making and decorative element defining their
architecture as of being composed by ‘ the organization of lines, surfaces, masses
and volumes in space’. [ He.S. p 909 ]
Fortunately in the following years, the concept of vaulting as a constructional method
for covering a space, was followed by a series of disadvantages ( due to its form ) and
corresponding solutions. As a matter of fact, this becomes the first incentive for
for the elaboration and experimentation of the arch, in various combinations of its
– 4 -
form to exploit further its peculiarity as a structural, space-making and decorative
element. Consequently the initial period of Roman architecture
was followed by a new Romanesque style which as a term, does not attempt to define
a particular period in architecture but categorizes a period in which the architecture
resembles the Roman during the 11th and 12th centuries, based on the arch form. [ He.S. p 926 ]
To begin with – as regards this particular transition – when vaulting was required to
span more than a corridors width in order to cover grand scale buildings a
constructional problem arose. According to the structural principal of the arch, barrel
vaults exert thrust along their entire length. If applied over buildings of great
dimensions, massive walls with limited openings in number and size would had to be
constructed along their entire length in order to count resist the thrust exerted.
Especially for public buildings such as the basilicas, this would be a disadvantage
since it prevents light and circulation.
The solution to this problem was ultimately solved when the Roman builders
discovered that by the intersection of two barrel vaults forming an elliptical
embodiment known as a groin, the thrust is directed to the four corners formed by the
intersection at the lowest part and four corresponding piers down which the thrust is
conducted provide the support. Accordingly, the groins were repeated in parallel
series of rectangular areas eliminating the mass of continuous walls. Thus, by groin
vaulting less materials were utilized and more floor space was granted.
Admittedly, a form such as the groin is quite confusing as one can imagine. In order
to procure such a form during construction the corresponding form by scaffolding was
required which having to reach a certain height led to the alternative solution of rib
vaulting. By reversing the procedure of groin vaulting, semicircular arches spanning
diagonally applied as a frame for pouring the masonry to form the vault, substituting
the elliptical curves naturally formed by the intersection for which transverse and
horizontal arches also applied as they were necessary to apportion the weight of the
vault. To meet this, the point of intersection formed by the ribs reached
higher than the summit of the transverse and horizontal arches since the height of a
semicircular arch is dictated by its width. What could reach the same height
without affecting the given span of the transverse and horizontal was the pointed arch.
Thus, from groin to rib vaulting the rectangular area consists of two diagonal arches –
regarded as ribs – and four pointed arches spanning the sides. [ He.S. p 884 ]
The reversed process of working the structural components in the first place provided
the potential to amplify the dimensions of a vault determining it as the basic design
element in church and cathedral architecture where regarded as the nave, it concerns
the large seating space for the congregation.
In England, after the spread of the prevailing Roman Empire throughout Europe, there
are numerous churches and cathedrals that exemplify Romanesque architecture by
depending largely on the arch for their construction. But apart from the structural and
space-making advantages derived from the arch, there was a range of highly elaborate
carvings during this period that overlaid in recessed arches of doorways and
windows ( Figures 7-10 )producing lavishly effects for which the churches and
cathedrals were admired [ Parker J.H. p42 ] whilst the monks worked on them under
the belief that the more elaborate, the more work was done in the eyes of God.
[ Scott Robert A. p 58 ]
Some of these carvings were the star, the billet, the billet and lozenge, and the
most recurring type which was the zigzag ornament ( Figures 11 ), carved in
diminutive and larger scale arcading in the interior of a cathedral ( Figures 12,13 ).
Figure 7 ( Drawn by author ) Figure 8 ( Drawn by author )
St. John Devizes church (window) Iffley , Oxon church (window)
Figure 9 ( Drawn by author ) Figure 10 ( Drawn by author )
Cuddesdon , Oxon church (doorway) Middleton Stoney , Oxon church (doorway)
Figure 11
The Star The Billet The Billet and Lozenge The zigzag with beads
-7-
Triforium arcade, Peterborough cathedral
Figure 12
Although successful vaulting was achieved by the introduction of the pointed arch,
the diminutive arcading as well as the arches over doorways and windows remained
semicircular as can bee seen in Durham cathedral which stands as one of the finest
examples to distinguish the Romanesque period.
Figure 13
Nave in Durham cathedral
Consequently when the pointed arch applied utterly in the design of a cathedral,
Romanesque shifts to a Gothic period in which the pointed arch proves the advanced
structural and space-making capabilities it possesses. The new technology of the
pointed arch led to alternative structural methods achieving broader and taller
buildings in which the introduction of light is distinct and heightens the sheer size of
the interior.
This particular improvement is derived is from the basic principal of the pointed
arch which unlike the semicircular, exerts thrust at a steeper angle conducting the
loads more efficiently towards the supports thus reducing the outward push at the
points of abutment. This gives ground for less abutting wall area to suffice for
resisting the reduced outward push and thus, columns were reduced in size, and more
floorspace was granted in every location where load bearing supports had to apply
( Figures 14 ,15 ).
Figure 14 Figure 15
Vaulted chambers of the Bishop’s Palace, Wells Western Romanesque crypt Canterbury cathedral
In order to achieve the same for providing maximum width for the aisles along the
sides of a nave as circulation paths beside the seating areas, were constructed an
exterior system of half arches – the so called flying buttresses –in order to count resist
the thrust of the transverse arches. These flying buttresses channel the outward push
of the transverse arches obliquely towards lower and heavier buttresses constructed
againsts the perimeter walls of the cathedral ( Frankle P. pp 86-87 ). Thus, by
eliminating the lateral thrust of the building transversely, expansive areas of glass
substituted the masonry of the wall intervals between the buttresses to achieve interior
illumination also accentuating the interior volume of space.( Wodehouse L. P 230 )
9
During a later Gothic phase dominated the Perpendicular style ( A.D. 1189 – 1272 )
featuring a high sense of linearity through its forms the most characteristic of which is
the fan vault. Transverse horizontal and diagonal arches form part of a concave sided
cone incorporating intermediate ribs springing from the centre after reaching a certain
height. These cones apply in a series vertically halved with their axes defining the
width of circulation passages leading to important rooms necessary for the monastic
life of the monks [ Lang- Sims p 146 ]. The fan-like appearance of the ribs resemble
the route of forces from ceiling to ground proving both structural and space-making
purposes of this form. At Canterbury cathedral the rectangular areas formed on the
ceiling of the Great Cloister’s fan vaults ( Figures 16, 17 ), blend with the ribs by
joints – like webbing – containing miniature shields of arms as bosses that mask
the numerous points of intersection formed by ribs ( Figure 18 ).
Figure 16 Figure 17 Figure 18
Miniature shields of arms Great Cloister’s north fan vault Nave in Canterbury Cathedral
What is more noteworthy during this period is the elimination of capitals on which the
arches do no longer abut, but are the continuation of each individual of the grouped
piers ( Figure 18 ). The reversed process of constructing the structural components in
the first place to improve the geometric surfaces of groin vaulting during the
Romanesque period the method of which evolved from the Roman period, visually
results in the late Gothic phase as a unitary spectacle of geometrically related
components forming a unified whole. [ Frankl P. pp 86- 87 ]
It is clear – out of the pure forms of verticality- how a change of direction towards a
bond immediately generates a structural, space-making and decorative element: the
arch. Capable of serving individually or simultaneously these three purposes
stands as one the greatest innovations in architecture reflecting the ambition and
necessity for erecting grand scale structures, and always having the potential to
evolve.
- 11 –
Bibliography:
Sources
Frankl P. (2000) Gothic Architecture. Revised edition by Paul Crossely. New Haven
and London. Yale University Press.
Jackson T.G. (1913) Byzantine and Romanesque Architecture. Cambridge University Press.
Lois- Sims L. (1979) Canterbury Cathedral. 35 Red Lion Square, London, Cassell LTD.
Parker J.H. (1900) ABC of Gothic Architecture. 11th edition. 6 Southampton street, Strand, London. James Parker and CO.
Scott Robert A. (2003) The Gothic Enterprise. Berkeley, Los Angeles, London. University of California Press
Wodehouse L. ( 2003 ) A World History of Architecture. 71 Great Russel Street London, Laurence King Publishing
Images
Figure 1. Arch of Titus, Rome. [online image]. Available from www.artlex.com
[accessed 10 March ]
Figure 2. The underside of the Arch of Titus.[online image]. Available from www.artlex.com [accessed 10 March ].
Figure 3. Centering. ( Drawn by author )
Figure 4. Roman aqueduct at Pont du Gard, France. [online image]. Available from
www.artlex.com [accessed 10 March ]
Figure 5. System of corridors and stairways. (image from: Roman Architecture, Thorpe Martin, p57 )
Figure 6. The Colosseum in Rome. [online image]. Available from www.prolinguis.ch/languages-studies-abroad-sc… [accessed 10 March]
Figure 7. St. John Devizes church (window). ( Drawn by author )
Figure 8. Iffley , Oxon church (window). ( Drawn by author )
Figure 9. Cuddesdon , Oxon church (doorway). ( Drawn by author )
Figure 10. Middleton Stoney , Oxon church (doorway). ( Drawn by author Figure 11. The Star, The Billet, The Billet and Lozenge, The zigzag with beads (image from: ABC of Gothic Architecture. pp56-57 )
Figure 12. Triforium arcade, Peterborough cathedral. (image from: ABC of Gothic Architecture. p 49 )
Figure 13. Nave in Durham cathedral. [online image]. Available from www.wearsideonline.com [accessed 13 June]
Figure 14. Vaulted chambers of the Bishop’s Palace, Wells. (image from: ABC of Gothic Architecture. p 113)
Figure 15. Western Romanesque crypt Canterbury cathedral. (image from : Canterbury Cathedral, Lois- Sims L. p 29 )
Figure 16. Miniature shields of arms. (image from : Canterbury Cathedral, (image from: ABC of Williamson H.R. p 40)
Figure 17. Great Cloister’s north fan vault at Canterbury cathedral. (image from : Canterbury Cathedral, Williamson H.R. p 41)
Figure 18. Nave in Canterbury Cathedral. (image from : Canterbury Cathedral, Williamson H.R. p 11)
Credit:ivythesis.typepad.com
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