Islamic Arches

Islamic architecture is characterized by arches which are employed in all types of buildings from houses to mosques. One of the most common uses is in arcades where arches span a series of columns or piers to form a gallery open on one side. Arcades are used to line mosque courtyards although they are also used in courtyard houses. An example in Dundee is situated at the Salvation Army building next to The Overgate parking block.

The earliest forms of arches employed in Islamic architecture were the semi-circular round arches which were characteristics adopted by the Roman and Byzantine architecture. This leads to structures of a mass scale being built at a time when the British where confined in there small spaces. The large uninterrupted space was essential as in prayer men are to stand shoulder to shoulder in rows without any gaps. As large communities of men are in regular 5 times prayer a day the right mosque was needed (although not essential as before they prayed anywhere with just a prayer mat/palm leaves each).

Fairly soon after the Islamic conquests a new type of pointed arch began to develop. Round arches are formed from a continuous curve which has its centre at a point directly below the apex and level with the springing of the arch on either side. This is now known as the old shouldered arch. Pointed arches are made by forming each side of the arch from a different centre point, the greater the distance between the two points the sharper the point. This meant the buildings could be made even larger and the new window frames had a solid structure to withstand the circumference force of the large domes.

In the Dome of the Rock (The third most holy site of Islam based in Palestine) built in 691 have arches supporting the dome that are slightly pointed whilst in the cisterns at Ramla built in 759 there is a pronounced point. The arches at Ramla are formed by a separation of the points by a distance of one-fifth the span of the arch; this ratio became standard in many early Islamic buildings.

Another arch form developed during the early Islamic period is the horseshoe arch. Horseshoe arches are those where the arch starts to curve inwards above the level of the capital or impost. Horseshoe arches were developed in Syria in pre-Islamic times and have been recorded as early as the fourth century CE in the Baptistery of Mar Ya'qub at Nisibin. The earliest Islamic monument with horseshoe arches is the Great Mosque of Damascus where the arches of the sanctuary were of slightly horseshoe form. However, the area where horseshoe arches developed their characteristic form was in Spain and North Africa where they can be seen in the Great Mosque of Cordoba. In Tunisia the horseshoe arches of the Great Mosque of Qairawan and the mosque of Muhammad ibn Khairun have a slightly pointed form. This shows that although they all followed the same style the arabs were more innovative in the way they tweaked the style for it to become personalised. This again was echoed in the British Gothic era and replicated (to a degree).

Probably the most advanced arch form developed in the early Islamic period is the four-centre arch. This is a pointed arch form composed of four curved sections each with its own centre producing an arch with steep curves lower down and flattened point at the apex. The earliest occurrence or the four-centred arch is at Samarra at the Qubbat al-Sulaiybiyya. Another arch form which makes its first appearance at Samarra is the cusped arch which is used in the external decoration of the Qasr al-Ashiq. This arch form later became one of the favourite decorative arch forms used throughout the Islamic world from Spain to India. This is now known as the shouldered arch. This is the most commonly used style in mosque nowadays becoming an instantly recognisable symbol of islmaic architecture. The geometric decorative designs filled these architectural windows along with Arabic calligraphy and green coloured glass windows. (Green because it is said to be ALLAH’s favourite colour as there are many references to it for example men and women will wear clothes of green in heaven.)

Arches were not used in India before Islamic times where trabeate construction was the main method of roofing an area. However, arches were regarded as essential by the first Muslim rulers who built arched screens in front of trabeate structures such as the Quwwat al-Islam Mosque in Delhi. Even the screens of the earliest Indian mosques were not composed of true arches but were corbelled structures made to look like arches. So this is purely and souley Islamic architecture at it’s best!

Pictures from:
http://www.astro.uvic.ca/~jwillis/photos/Syria/tn/IMG_1804.med.JPG

http://www.thai-eu-cultures.com/Espana/7-Plaza.jpg

http://www.youngartists.com/Ibun%20Tulan

http://www3.estart.com/stores/media/aqsa.gif

Domes

It was originated as a roofing method where the absence of suitable timber meant that it was impossible to make a flat timber roof. The earliest domes in the Middle East were associated with round buildings and were produced out of mud brick placed in layers which tilt slightly inwards.

When the Romans conquered the Middle East the dome was incorporated into Roman architecture and under the Byzantines it became the main method of roofing monumental buildings.

The chief advantage of domes is that large areas can be roofed without the interference of columns. At this time the wooden dome was developed which combined the space of dome building with the flexibility and lightness of wood. By the seventh century wooden domes were a normal method of roofing mosques and churches.

Wooden domes were usually covered with sheets of metal, either copper or lead, as protection against the weather. Most domes, however, continued to be built of less flexible materials such as stone, mud brick and baked brick. One of the main problems of dome construction was the transition from a square space or area into a circular domed area. Usually there was an intermediary octagonal area from which it is easier to convert to a circular area although there is still the problem of converting from square to octagon.

Two main methods were adopted, which are the squinch and the pendentive. The squinch is a mini-arch which is used to bridge a diagonal corner area whilst a pendentive is an inverted cone with its point set low down into the corner and its base at the top providing a platform for the dome. Squinches are the main method of transition in pre-Ottoman architecture whilst pendentives are more common after the sixteenth century. In India, arches where there was no tradition of before the advent of Islam, domes rest on flat corbels which bridge the corners.

Squinch:










Pendentive :

During the medieval period Islam developed a wide variety of dome types which reflect dynastic, religious and social distinctions as well as different construction techniques. One of the most extravagant dome forms is the Muckarnas or conical dome which appears as early as the eleventh century in Iraq at Imam Dur. A conical dome consists of multiple tiers of Muckarnas which blur the distinction between structure and decoration and between circular and square forms. Later on the idea of the double dome was introduced as it was recognized that there was a conflict between the external appearance of the dome and the aesthetics of the interior of the domed space. The result was tall external domes with shallower interior domes. Increasing emphasis on the exterior can be seen in Cairo and Egypt where masonry domes with intricately carved exteriors were developed. In Iran and Central Asia tall domes were covered in coloured (usually blue) glazed tiles, culminating in the huge bulbous fluted domes on a high circular drum which were characteristic of the Timurid period (fifteenth century). In pre-Mughal India the standard dome form was derived from Hindu architecture and consisted of a squat circular form with a lotus design around the apex and a characteristic bulbous finial. Ottoman architecture adopted the Byzantine dome form and developed it to produce vast domed areas such as that of the Selimiye in Edirne.

Muckarnas Dome:










Pictures from:

Squinch Dome:
http://www.arts.auckland.ac.nz/ahist/arthist111/ways_of_building/Images/squinch.gif
http://www.islamicarchitecture.org/art/images/techniques/squinch.gif

Pendentive Dome:
http://www.faculty.sbc.edu/wassell/ArchMath/Unit5/images/pendentive.jpg
http://www.brynmawr.edu/Acads/Cities/wld/00980/00980km.jpg

Mukarnas Dome:
http://www.mrfs.net/trips/2003/Spain/Nasrid_Palace/dome.jpg
http://www.sakkal.com/islamic_geometry/images/gaghard/geghard03.jpg