Construction Techniques used in Historical Structures

1. Construction Techniques used in Historical Structures

2. Different techniques were used by man at different eras. Not only at different eras, but also at contemporary times the techniques varied from one region to the other based on culture, science, technology availability, raw materials, economy, needs, etc.

3. Ancient world (3000 BC - 300 AD) • The pyramids • Stone henge • Civilizations • Temples • Medieval world (300 AD – 1600 AD) • Fortifications, Castles and cathedrals of Europe • Mosques of Middle East • Monuments of Asia • Modern world (1601 AD – till date) • Skyscrapers • Memorials • Green buildings

4. ANCIENT WORLD • The Pyramids • Found at four different regions • Middle east • Asia • South America • Europe • Middle east pyramids (Ziggurats) • The tradition of building in elevated stages was common in the Middle-east • ziggurat's were once found in most important Mesopotamian cities. • The word 'Ziggurat' is an anglicized form of the Akkadian word Ziqqurratum, the name given to the stepped towers of mud brick. It derives from the verb zaqaru, ‘to be high'. • Baked bricks were used for the lowest courses of walls. • For drains bitumen was employed to make them watertight. • Important buildings such as the ziggurat at Ur, might be encased in baked bricks as a protection against the elements. • Courses of reed matting and layers of bitumen were interspersed between those of brick in the construction of ziggurats to counteract rising damp from the foundations, and weep-holes also assisted drainage and prevented damp decay. • Bitumen was also employed as a water-proofing material for bathrooms and constructional timber such as doors.

5. The Saqqara step-pyramid was built with mud-fired bricks, identically fashioned (With mud and straw packed in wooden frames), to bricks made in Mesopotamia long before the time of Djoser. • In Hattusa of Turkey, The lowest levels of the foundation blocks of the great walls show a highly skilled masonry style, often referred to a 'Cyclopean'. • The Hittites rebuilt the great city, but whoever laid the original foundations left behind their familiar fingerprints in the masonry, still standing today. ziggurat at Ur The Khorsabadziggurat at the Mesopotamia

6. The brick works at The Saqqara step-pyramid Chichen Itza - (Abandoned Mayan city).

7.    South American Pyramids • The oldest 'Proto-Pyramid' complex in the America's is at Caral, in Peru. • In 1964, aerial photography identified nearly 1,000 pyramid sites in Peru • La Venta has one of the earliest pyramids known in Mesoamerica, the Great Pyramid is 110 ft (33 m) high and contains an estimated 100,000 cubic meters of earth fill. • Chichen Itza :The stepped pyramid-temple, it records the equinoxes in a unique way. The sun creates a shadow of a huge 'snake' which ascends the steps in spring, and descends again in autumn. • Other astronomical features at the site certainly lend weight to the idea that it was intentional. Each step corresponds to a day, each platform to a Mayan month. The temple is erected above the 365 steps. • These stairways also divide the nine terraces of each side of the pyramid into eighteen segments, representing the eighteen months of the Mayan calendar. • The pyramid is also directionally oriented to mark the solstices and equinoxes. The axes that run through the northwest and southwest corners of the pyramid are oriented toward the rising point of the sun at the summer solstice and its setting point at the winter solstice. • AcousticPhenomena at El Castillo: 'If you stand facing the foot of the temple and shout the echo comes back as a piercing shriek. Also, a person standing on the top step can speak in a normal voice and be heard by those at ground level for some distance. This quality is also shared by another Mayan pyramid at Tikal'. • The Ossario: This step-pyramid temple dominates the platform, on a small scale. • Like its larger neighbour, El Castillo, it has four sides with staircases on each side. There is a temple on top, but different from El Castillo, at the centre is an opening into the pyramid which leads to a natural cave 12 m. • The Largest Pyramid in the World: La Danta.:Archaeologists are in the process of uncovering one of the oldest and largest pyramid complexes in Mesoamerica. • The site in Guatemala is located in the Mirador Basin, within which over 30 pyramid complexes/cities have now been determined.

8. Egyptian pyramids · The great pyramid of Khufuwas built of 2.6 million blocks of limestone each of an average volume of One Cubic Meter, weighing 2.5 metric tons. This figure comes from the volume of the pyramid being 2,600,000 cubic meters. By the equation (230 x 230 x 148/3) The Area Of The Base Times One Third Of The Height. The substructure of the middle kingdom pyramid of King AmenyQemau of the mid 13th dynasty 1700 BC at south Saqqara. Drawn by JaroslawDobrowolski 1997 for Nabil Swelim after Maragioglio V. and Renaldi CA.

9. It is a fact (whether through accident or design), that the dimensions of the Great pyramid form an accurate representation of the northern hemisphere of earth. (Apothem - 1/2 base = 1.6181 (Ф), and   Height x 2∏ = Perimeter)  Herodotus (440 BC), recorded that priests told him then that the Great pyramid was designed so that the area of each This means that the designers incorporated Pi (∏), and Phi (Ф) in the following fashion.

10. The layout of the pyramids reveals the application of the 'sacred mean' - a 5:8 ratio. In 'The Great Pyramid Decoded, Peter Lemesurier writes, "It would be a rash man who undertook to find, even today, a building more accurately aligned to the True cardinal points of the compass, masonry more finely jointed, or facing-stones more immaculately dressed.... the sceptic may doubt that many of the pyramid's stones -- some of them weighing up to seventy tons -- were so finely cut and positioned as to give joints of less than a fiftieth of an inch in thickness'; '...he may scoff at the claim that a fine cement was run into these joints so expertly as to give an even coverage of single areas as big as five feet by seven in the vertical; he may express profound disbelief when it is pointed out to him that the building's now almost totally despoiled original outer casing of polished limestone (all twenty-one acres of it) was levelled and honed to the standard of accuracy normal in modern optical work. But these, as it happens, are facts which anybody may check who cares to'.

11. Machu Pichu, Peru (above)Luxor, Egypt (below) • Techniques used in building pyramids •  Folded Corners • Several structures show the blocks cut with an internal angle, so as to 'fold' the stone around corner's. It is suggested that this was incorporated as an earthquake 'preventative'. • Valley-Temple, Ghiza, Egypt. - There are several stones with this design feature in the valley-temple. It is interesting to note that the stones  have been cut so as to continue only a short distance around the corner which hints at the idea that style might have been involved. •  Multi Facetted Stones: • This design feature was incorporated into constructions as an 'earthquake' preventative. The fact that the constructions exist in such good condition after so long, in itself supports this idea.

12. The Inca masonry of south America is Multi-faceted stones - Valley- temple, Ghiza, Egypt.probably the finest the world has ever seen. • Metal blocks • Another construction feature commonly suggested as an earthquake preventative is the means used to join huge blocks together. It is believed that copper (or silver) was used at Tiahuanaco (below), both of which are soft metals. • Were mostly used in Egypt and Cambodia at Ankor Watt.

13.  Mortise and Tenon Joints: • This particular construction feature is reasonably explained as having followed the transition from building structures first from wood then stone. • Mortise-and-tenon joints had, of course, been used previously in Bronze Age ships in Egypt, as in the construction of the Khufu’s boat at Giza (ca. 2600 B. C.) and Senwosret III’s boats (ca. 1850 B.C.) at Dashur (Lipke 1984, 64; Steffy 1994, 25-27, 32-36, Patch and Haldane 1990).  These early Egyptian examples of mortise-and-tenons, however, were freestanding and not pegged to lock adjacent strakes to one another.  Rather, their primary function was to align the planks during construction, which were then fastened to each other with ligatures.  This tradition of shipbuilding appears to have persisted at least as late as the 5th century B.C. • The Stonehenge Sarsen Stones: In its complete form the outermost stone setting would have consisted of a circle of 30 upright sarsen stones, of which 17 still stand, each weighing about 25 tons. The tops of these uprights were linked by a continuous ring of horizontal sarsen lintels, only a small part of which is now still in position. The stones in the sarsen circle were carefully shaped and the horizontal lintels joined not only by means of simple mortise-and-tenon joints, but they were also locked using what is effectively a dovetail joint. The edges were smoothed into a gentle curve which follows the line of the entire circle.

14. The Use of Concrete in Ancient Structures • Examination and measurements of the boulders used in building the pyramid show an unusually high moisture content (apparently the kind one would expect to find in concrete). • The highly polished limestone casing stones that covered the pyramid were fixed with a 'fine aluminosilicate cement'. The finished pyramid contained approximately 115,000 of these stones, each weighing ten tons or more. These stones were dressed on all six of their sides, not just the side exposed to the visible surface, to tolerances of .01 inch. They were set together so closely that a thin razor blade could not be inserted between the stones. • Egyptologist Petrie expressed his astonishment of this feat by writing: - 'Merely to place such stones in exact contact would be careful work, but to do so with cement in the joint seems almost impossible; it is to be compared to the finest opticians' work on the scale of acres". The immense White-quartz, portal-stones at CastelrudderyHenge-Circle in Ireland.

15. The Specific Selection of Stone • While it is apparent that the megalithic builders showed a preference for certain stone types, the reason for this has yet to be explained satisfactorily. The extra distance and effort required to employ specific stones in ancient structures offers us with a clue as to the possible motivation of the builders. • In ancient Egypt, the pyramid and temple builders went to great lengths to include granite in their sacred buildings, transporting it hundreds of miles in preference to the more readily available limestone. • At the Boyne-Valley complex in Ireland, the stone material used in the major passage mounds of Newgrange and Knowth come from several sources, two of which are approximately 40km south and 35km North east of the monuments  • Excavation of the Aztec 'Templo Mayor' site in Mexico, produced a funerary casket, from the inner-most layers of the pyramid, beneath a Chac-mool statue, 'thought to represent the god Quetzalcoatl'. Within the casket were found several crystal artefacts which included; Several crystal cylinders, thought to represent the 'feathered tail of Quetzalcoatl'. Crystal Lip-plugs, crystal ear-spools and a row of thirteen crystal beads 'thought to have been part of a necklace'.  • Stonehenge has at least four different types of stone in the overall  structure, each brought from different locations: Over 80 5-10 ton 'Bluestones'' from Wales, the huge 20-50 ton 'Sarsens' from 20km north near Avebury, the mica-sandstone 'Slaughter stone' from Milford Haven, and the limestone packing-stones from Chilmark. • Although the area just north of Stonehenge is littered with perfectly suitable sarsen stones, the builders chose to use over 80 Bluestones instead, requiring them to transport them over 200 miles from the Presily mountains in Wales.

16. STONEHENGE, ENGLAND Archaeologists believe it was built anywhere from 3000 BC to 2000 BC, as described in the chronology below .Radiocarbon dating in 2008 suggested that the first stones were raised between 2400 and 2200 BC, whilst another theory suggests that bluestones may have been raised at the site as early as 3000 BC The monument we see today is the result of several different construction phases with the same area having been used long before Stonehenge itself existed as testified by the adjacent Cursus and large post-holes, both dated from well before any of the acknowledged construction phases

17. . It is believed that the ditch was dug with tools made from the antlers of red deer and, possibly, wood. The underlying chalk was loosened with picks and shoveled with the shoulderblades of cattle. It was then loaded into baskets and carried away. Modern experiments have shown that these tools were more than equal to the great task of earth digging and moving. About 2,000 BC, the first stone circle (which is now the inner circle), comprised of small bluestones, was set up, but abandoned before completion. The stones used in that first circle are believed to be from the Prescelly Mountains, located roughly 240 miles away, at the southwestern tip of Wales. The bluestones weigh up to 4 tons each and about 80 stones were used, in all. Given the distance they had to travel, this presented quite a transportation problem.  It is now well known that the simplest means of modelling the movements of the Sun and Moon (Tides) is with a circle of 28 markers around a central earth. Moving a 'Moon-marker' one position per day and a 'Sun-marker' once every 13 days, provides a calendar accurate to 98%. By doubling the sun-moon calendar to 56 markers, one can obtain an accuracy of 99.8%, with the additional  benefit of being able to predict eclipses to high accuracy. The combination of astronomically relevant orientations and means of accurate calculating both solar and lunar cycles with the same 'monument/device' offers the clear possibility that the (original) builders were already aware of 'Metonic' cycle, whereby both the cycles of the sun and moon synchronise over a period of 18.6 solar years or 235 lunations with an error of only 2 hours.

18. The Altar Stone • Lying in the geometric centre of the monument is a worked recumbent megalith. It was most recently excavated in the 1950s, but no written records of the excavation survive. The Alter Stone measures 16 feet long, 1 foot 9 inches deep and 3 feet 4 inches wide.Hawkins (3) makes note that while all the other stones were either bluestone or sarsen, the so called altar-stone is 'of fine-grained pale green sandstone, containing so many flakes of mica that its surface, wherever freshly exposed, shows the typical mica glitter'. The stone when standing would have reflected the sunlight enhancing the effect of the summer solstice sunrise. The last phase of  development (Phase III), at Stonehenge shows a clear geometric foundation, with the 30 equally spaced upright sarsen-stones set in a perfect circle.

20. The most famous building executed in the Hindu/Jain temple style is Angkor Wat, a temple found in the region of Angkor, Cambodia. Angkor served as capital of the medieval Khmer Empire, the mightiest empire in Southeast Asian history. Originally a Hindu realm, the Khmer Empire eventually converted permanently to Buddhism; this explains why Angkor Wat, originally constructed as a Hindu temple, later became a Buddhist temple (which it remains today). Angkor Wat is the largest religious building on Earth. • Nalanda • Nālandā was an ancient center of higher learning in Bihar, India. The site is located about 88 kilometres south east of Patna, and was a religious center of learning from the fifth century CE to 1197 CE.Nalanda flourished between the reign of the Śakrāditya (whose identity is uncertain and who might have been either Kumara Gupta I or Kumara Gupta II) and 1197 CE, supported by patronage from the Hindu Gupta rulers as well as Buddhist emperors like Harsha and later emperors from the Pala Empire. • Excavations conducted by Archaeological Survey of India during 1915–37 and 1974–82 have exposed the extensive remains of six major brick temples and eleven monasteries arranged on a systematic layout and spread over an area of more than a square kilometre. Basically a hundred feet wide passage runs north-south with the row of temples on the west and that of the monasteries on the east of it.

21. The complex was built with red bricks and its ruins occupy an area of 14 hectares. At its peak, the university attracted scholars and students from as far away as Tibet, China, Greece, and Persia.Nalanda was ransacked and destroyed by an army under BakhtiyarKhilji in 1193. The great library of Nalanda University was so vast that it is reported to have burned for three months after the invaders set fire to it, ransacked and destroyed the monasteries, and drove the monks from the site • The monasteries are quite identical in general layout and appearance. Central courtyard, row of cells all around with a common verandah, a secret chamber for keeping valuables, staircase for going to upper stories, kitchen, well, granary, single entrance and common place for prayer or meeting etc. are some characteristic features of almost all the monasteries at Nalanda. The main temple site 3 is the largest and most imposing structure at southern extremity of the row of temples and is surrounded by votive stupas.

22. Medieval World • Churches • The great architecture of medieval Europe was predominantly sacred. The primary sacred building type of Europe is the church, a structure for Christian worship. The most prevalent church layouts are the Latin cross church (in Western Europe) and central-plan church (in Eastern Europe). • While Byzantine architecture remained relatively faithful to the simplicity and balanced proportions of Roman buildings, a dramatic transition away from classicism occurred in Western Europe, as the Germanic peoples built churches of ever-increasing intricacy and verticality.  • Styles of church architecture were often adapted to other monumental buildings of the medieval period, including residences, town halls, and market buildings. The greatest secular building type was the castle, a medieval Western fortress. • These structures include the chapel (a place of worship that is relatively small compared to a church; many churches contain chapels, allowing for private worship), baptistry (a building in which the ceremony of baptism is performed), shrine (which honours a holy figure or place, and may contain relics), and mausoleum (an above-ground tomb). Minor Christian buildings tend to feature central-plan designs. (The term “central-plan” denotes rotational symmetry; if the plan is rotated around its central point, it looks the same at multiple points of rotation.) LATIN CROSS CHURCH VS. CENTRAL-PLAN CHURCH

23. Fine stone masonry: used only for public works, royal buildings and ecclesiastical buildings of royal importance: always using either arched cut stone spans or vaulted timber spans at roof level. Many such superb constructions still exist and are still in use today. Built to last. • The chief obstacles to construction of these buildings were the costs of material supplies and journeyman tradesmen, and the expertise of engineering required. Many royal landowners bank rupted themselves trying to pay for the cost of colossal stone buildings, and the pride of cities depended upon their ability to finish a cathedral once begun. • Every part of the building was designed for a long lasting and maintenance free usage. The gutters required lead. A very expensive metal. The domes required heavy copper sheathing. Shed roofs were finished in high grade slate, which was very heavy, and required very heavy roof frame to support it. A heavy roof demanded a massive structural framework down to foundations. • A cathedral spire two hundred feet high, or a large span across an eight foot high cathedral alter vault, would mean additional supporting structural loads which mounted greater and greater stresses as the loads work down to reach the ground. Eventually such dead loads at ground level meant absolutely huge foundation work under the point loads and shear walls. This took a lot work, which money, a lot of money. • Once up, these buildings had to be finished inside out, stained glass with huge structural metal framework, finely worked hardwood detailing reaching up the vast walls and across ceilings and mezzanines, furnishing sound enough to take the usage of public throng over hundreds of years had to be of very heavy construction, while the usage of the buildings required this heavy furniture to br finely detailed and recorded. • Interior finishes by master carpenters and sculptors needed to be executed as well as possible, without any regards to cost. These public works were intended to instill pride of ownership, not only on royal authorities but also in the hearts of the people who use them. To this effect, these buildings were unbelievably successful, in that they actually instill pride of ownership in the public six and seven hundred years after they were built.

24. Slate and also clay tiles were used for roofing so that the roof may be water and damp proof and maintenance free at least a generation. • Stucco plaster on woven stick lathe backing: “wattle and daub” infill, usually used for the construction of the early medieval saxon manor houses and very few of them remail.

25. Castle construction was an expensive undertaking. Castle building employed about 3,000 workers (like carpenters, masons, diggers, quarrymen and blacksmiths) under the direction of a master builder. Castles generally took two to 10 years to build. The building materials are stone, clay soil and oak trees that are found near the site. The workers use traditional techniques from the 13th century. To split stones for the walls, quarrymen "read" the rock face to see the lines where it will fracture. They then drive a line of holes into the stone and then pound corners into the holes, which makes shock waves go through the stone and break it. Workers use horse-drawn wagons to haul the stones from the quarry to the building site. Stone masons then chisel the raw stone into blocks. Workers use man-powered cranes to lift the finished stones to the scaffolding on the castle wall. Other workers make mortar on the site from lime, soil and water. The masons on the wall fit the stones together and use the mortar to hold the blocks together. Workers use traditional tools to measure and lay out castle pieces. For example, craftsmen use a long rope with knots placed every meter to measure wood beams and layout pieces. They also use wooden right angles and calipers for measurements. They use a wooden triangle with a line and plumb bob suspended from one angle as a level when placing stones. As the castle wall gets higher, new scaffolding must be placed in the wall and the old ones removed, leaving square holes in the walls. As of 2007, Castle Guedelon is about a third complete. Once a castle was completed, it was ready for defense. Let's look at medieval siege techniques and the strategies used by both sides.

26. These early castles laid the foundations for developments of castles in the High Middle Ages. • Stone and brick walls replaced wooden ones. Stone walls were sturdier and could be built much higher. • In some castles, an inner wall was added, forming a concentric ring. This extra wall provided more defenses. • The bailey became larger and divided into separate courtyards. • The donjon became larger and made of stone -- and its name changed to the keep. • Other buildings were added in the baileys -- like great halls, palaces, chapels, residences for knights and servants, stables and workplaces for craftsmen. • Several large, tall towers were built into the castle. Some towers were incorporated into the outer walls, while others were freestanding structures within the courtyard. • Some castles had a substantially higher outer wall called a shield wall. The shield wall was often placed on the side of a castle that might be especially vulnerable to siege weapons like catapults, trebuchets and siege towers (more on this later). The shield wall could also prevent objects from going over the walls into the bailey.

27. Castles • Early Medieval Times • The first castles, built in the Early Middle Ages (early Medieval period), were 'earthworks' - mounds of earth primarily built for defence, as enemies struggled to climb them. • During the 1000s, the Normans developed these into Motte and Bailey castle designs. • Effectively, a 'Motte' was a large mound of earth, and a 'Bailey' was the flattened area beside the mound. The 'Motte' could be surrounded with a ditch, and buildings could be placed on the bailey - made of timber or, if time permitted, stone. • The key benefit of Motte & Bailey castles was that they were very quick to build, but very difficult to attack. These castles were one of the primary reasons why the Normans succeeded in conquering so much of Europe. • A brilliant model of a Motte and Bailey. You can see the elevated keep on the tallest part of the Motte; and a slightly elevated domestic area on the Bailey below.

28. Commonly, timber was used to build towers, which could be used to shoot arrows at intruders. Where time and money allowed, stone keeps began to be built. These stone buildings offered much greater protection and defensive capability - albeit it at significant cost and effort. • Advantages of Motte and Bailey castles • Cheap and easy to build - you could even use an existing mound or hill for foundations • Didn't require and specialist materials - earth and timber were always nearby • Didn't need any time to plan a design too carefully - could be built withunskilled men who'd never even seen a castle before • Could be build quickly - allowing the conquerors to move onto the next town • Surprisingly hard to capture - the height and ditch gave quite a big advantage against attackers • Disadvantages of Motte and Bailey castles • Timber burns easily -and attackers quickly learned that firing flaming arrows could defeat the castle • Timber rots, too - castles quickly ran into disrepair, and often became abandoned by their owners • Mottesoften had a broad base. This often made defense tricky, as enemies could climb the hill from many different directions • Building a large Motte was a disproportionately difficult task - larger hills require much more piled earth than smaller hills - it's disproportionately hard to build a large castle • Although the base of the hill may have been large, the bailey at the top was often quite small. This meant that the living quarters for the noble were quite small - and didn't have much grandeur.

29. Shell Keep Castles • During the 1100s and 1200s, engineers came up with a way to strengthen old Motte and Bailey castles. • To do so, they built a 'shell keep' - a thin ring of stone around the buildings on top of the castle Motte (mound). This ring of stone replaced old, sea, wooden fencing. • Some great examples of this type of design are Restormel Castle in Cornwall, UK; Wiston Castle in Wales, UK; and I'd also include Clifford's Tower in York, UK. All are pictured on this page. • Restormel Castle in Cornwall, England

30. How the Shell Design Solved the Problems of Motte and Bailey Castles • The early-Medieval Motte and Bailey design was typified by its use of simple materials and straightforward building techniques. • On top of the motte (the man-made mound), defendants typically built wooden towers and wooden palisade fencing to protect the castle. Additionally, this wooden palisade fencing was utilised to protect the outer bailey - an adjacent, raised area with a flat top, which housed residential buildings. • The Disadvantages of Shell Keep Designs • Most shell-keeps were relatively small in size - no more than 25-50m in diameter - and encircled only the top of the Motte (rather than wrapping around the base of the hill, too). They tended to be light, short constructions, with relatively short, thin walls. • Well, it was all because medieval engineers approached shell-keeps with great concern and caution. The mound of the motte was often man-made (that is, an artificial pile of earth rather than a naturally-formed hill). Their concern was that a heavy shell upon a man-made motte would cause the hill to subside and everything atop to collapse or be destroyed. • Mid-Medieval Times • There were many problems with stone castles - not least for the fact that they were generally cold, damp, and unpleasant to live in. • Thus man began thinking of huge castle with aesthetic appearances. • There came the Gothic and concentric castles.

31. Gothic Castles: A Mid-Medieval building style that's become synonymous with fear, spooks, and hauntings • In Mid-Medieval times, an architectural revolution began in Europe. This was the new, gothic style. The characteristics of gothic architecture emphasized larger and lighter windows, higher rooms, and more decorative castle designs. • Before Gothic Architecture came along, castles of early Medieval times were cold, dark and damp. Building technology was rudimentary, which meant that most castles were encumbered with tiny windows and leaky roofs. Worse still, the castles were often liable to attack - square towers could easily be toppled when attackers burrowed beneath just one of the corners. • Grand vaulted ceilings. The ceilings in gothic buildings were made of up grand, pointed arches, which created an interesting, vaulted effect. These vaults often gave the impression of height and majesty. They contrasted dramatically to the short and dark towers of older castles. The dungeons of Chillon Castle are a perfect example of the gothic. The vaulted arches are typical of gothic architecture; and the spooky surroundings have been featured in gothic novels and poetry. These flying buttresses are a feature of gothic architecture. They're part of the St Vitus Cathedral in Prague Castle.

32. Concentric Castles: The most defensive castle plan, used to deter attackers • Despite the developments in stone castle designs, Medieval attackers were increasingly able to penetrate their defences. Common techniques included burrowing beneath the corners of towers - undermining their foundations, and encouraging the castle to collapse. • To overcome this, castle designers added thicker outer walls - and then rings of extra outer walls. The idea of the concentric castle was then born in about 1270. • In castles built before 1270, a double-ring of castle walls was only used to 'reinforce' the outer curtain wall. • Materials • Materials that were used in the building of castles varied through history. Wood was used for most castles until 1066. They were cheap and were quick to construct. The reason wood fell into disuse as a material is that it is quite flammable. Soon stone became more popular. • Stone castles took years to construct depending on the overall size of the castle. Stone was stronger and of course much more expensive than wood. Most stone had to be quarried miles away, and then brought to the building site. But with the invention of the cannon and gunpowder, castles soon lost their power. • Walls • Height: Varied from castle to castle • Width: usually 2.5–6 m (8–20 ft) thick

33. Medieval Indian structures • BrgadishwaraTemple (1000s AD) • In south India, about 1000 AD, the Chola kingRajaraja the Great (his name means King-king) built a very big temple to the Hindu god Shiva. • The southern temple is also much longer than the northern one, and is has several porches on the front ( mandapas) instead of only one. Both the northern and the southern temples have flat stone roofs. • By 1061 AD, some builders in India started to use a new method of building using iron beams to replace wooden beams, because wooden beams were very hard to get in India. One example is Brahmeshwar temple in eastern India at Orissa. BragaishwaraTemple (1000s AD)

34. Indo-Islamic Art • With the rise of Islamic states as the dominant powers of South Asia (ca. 1200-1800), Indian art was subjected to Islamic influence, resulting in a hybrid aesthetic: Indo-Islamic. This aesthetic flourished most brilliantly as architecture and manuscript illumination. • The primary form of Indo-Islamic architecture is the mosque. The most obvious differences between an Indo-Islamic mosque and a “mainstream” Islamic mosque are two features adopted from Indian architecture: sculpted decoration and tower/dome shape. TajMahal

35. Materials • The TajMahal was constructed using materials from all over India and Asia and over 1,000 elephants were used to transport building materials. • The translucent white marble was brought from Makrana, Rajasthan, the jasper from Punjab, jade and crystal from China. • The turquoise was from Tibet and the Lapis lazuli from Afghanistan, while the sapphire came from Sri Lanka and the carnelian from Arabia. • In all, twenty eight types of precious and semi-precious stones were inlaid into the white marble. A labor force of twenty thousand workers was recruited across northern India. Sculptors from Bukhara, calligraphers from Syria and Persia, inlayers from southern India, stonecutters from Baluchistan, a specialist in building turrets, another who carved only marble flowers were part of the thirty-seven men who formed the creative unit. • The plinth and tomb took roughly 12 years to complete. The remaining parts of the complex took an additional 10 years and were completed in order of minarets, mosque and jawab, and gateway. • The remaining parts of the complex took an additional 10 years and were completed in order of minarets, mosque and jawab, and gateway. was essentially complete by 1643, but work continued on the rest of the complex. Estimates of the cost of construction vary due to difficulties in estimating costs across time. The total cost has been estimated to be about 32 million Rupees at that time. • The inner dome

37. Structural details of TajMahal • On a platform 22' high and 313' square. Each tower is 133 feet tall • Building is 186 feet high and 70 wide. • Corner minarets are 137' tall. Main structure 186' on a side, dome to 187'. • The mausoleum is 57 m (190 ft) square in plan. • z"The central inner dome is 24.5 m (81 ft) high and 17.7 m (58 ft) in diameter, but is surmounted by an outer shell nearly 61 m (200). • The Taj stands on a raised, square platform (186 x 186 feet) with its four corners truncated, forming an unequal octagon. • The architectural design uses the interlocking arabesque concept, in which each element stands on its own and perfectly integrates with the main structure. It uses the principles of self-replicating geometry and symmetry of architectural elements. • Its central dome is fifty-eight feet in diameter and rises to a height of 213 feet. • It is flanked by four subsidiary domed chambers. • The four graceful, slender minarets are 162.5 feet each. • The entire mausoleum (inside as well as outside) is decorated with inlaid design of flowers and calligraphy using precious gems such as agate and jasper. • The main archways, chiseled with passages from the Holy Qur’an and the bold scroll work of flowery pattern, give a captivating charm to its beauty. • The central domed chamber and four adjoining chambers include many walls and panels of Islamic decoration.

38. Mosques • Mosques were the prayer halls of the Muslims. • They were symbolized by round domes. • Most mosques were planned structurally. • This is evident from their shapes and long standing structures. • The mosque architecture of Dhaka is a unique example which has differentarchitectural qualities. The existing famous mosques of Dhaka surviveacross the city are, Lalbag Fort Mosque (1649 A.D.), KhawajaAmbar,Mosque(c.1680 A.D.), KarTalab Khan’s Mosque (1701-04 A.D.), KhanMuhammadMirdha’s Mosque (1706 A.D.), Haji KhwajaShahbazMosque(1679 A.D.), Satgumbad Mosque (c.1680 A.D.) and Musa Khan’ Mosque(18thcentury) • The unique features of these mosques are that, they haveperfect space and different structural ideas. The structure chosen for theapplication of traditional idea with both functional and aestheticdecorations are themihrab,2 the cornice, façade and the panels of interiorand exterior walls.  • he foundations of the Mughal mosques of Dhaka arequite functional which are based on mathematical measurement. Todaythree-dome, five-domed, seven-domed or multi-domed type of mosqueshave been seen. • Ground plan and interior structure are also differentiatingcharacter of these mosques. On the basis of ground plan Mughal mosquesof Dhaka are true Bengali type (Dani, 1961, pp. 21-22).

39. MamlukMason 1) Ahmad al-Qasid (c. 1335); 2) Tankizbugha (c. 1359); 3) Ulgay al-Yusufi (1373); 4) Aytmish al-Bajasi (1383-84); 5) YunisDawadar (1382) (after Kessler). • The internal and external profiles are drawn on two centers forming a shape of a pointed dome.

40. If we extend straight lines from the loops at the base of both domes to the center of the stars, we found that these lines are in coordination with the vertical joints of the stone blocks and divide the body of the dome into equal slices. • A whole star is included within two slices that were repeated using the principle of radial symmetry • It is found that the horizontal and vertical joints have no relation with the interlaced stars except the vertical joints that are in alignment with the centers of the stars. Connecting the stars’ centers, we discovered that a semi-regular tessellation grid composed of squares and triangles is the hidden structure of the star pattern of Barsbay’s dome

42. Conclusion Thus, various techniques and different civil engineering concepts have been used at different times in different buildings. Each historical structure has its own specialization and specialty in all aspects.