Archaeological evidence of earth building in South America is scant, with the richest area being the coastal regions of northern Peru. A recently discovered temple at the Ventarrón site in northern Peru appears to be constructed from blocks cut directly from river sediment, and has been dated to around 2000BC[50].The earliest recorded earth bricks relate to the Moche culture, which flourished in northern Peru between AD 100 and AD 800.
The centre of this civilisation was the city of Cerro Blanco, with two pyramids, dedicated to the sun and the moon. Huaca del Sol and Huaca de la Luna are adobe core pyramids around 50 m tall.
Distinctive marks on each adobe brick suggest that many different communities were involved in the construction of these structures.
Contemporary to the Moche culture was the Lima culture (AD 100–650) of central coastal Peru.
This culture also built adobe pyramids, such as the Huaca Pucllana (Figure 2.13) and the Huaca Juliana, the latter being 25 m tall and formed using
adobes stacked vertically. In the south of Peru the Nazca civilisation, most famous for the Nazca Lines, built its capital at Cahuachi in adobe, which is still being excavated today. Although there is little archaeological evidence of vernacular architecture, it is likely that both monumental and vernacular constructions used adobe bricks.
Figure 2.13: Huaca Pucllana, adobe pyramid in Lima, Peru. Courtesy of Louise Davies
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The collapse of the Moche culture around AD 750 led to the development of the Lambayeque
culture, who continued to build adobe pyramids at sites such as Batán Grande, Túcume and Apurlec.
The largest civilisation to develop following the decline of the Moche was the Chimu, who emerged around AD 900 and built their capital of Chan Chan close to the modern city of Trujillo in northern Peru.
Chan Chan was probably the largest city on the continent at that time, home to up to 26 000 people and surrounded by adobe walls around 15 m high.
Ten ‘royal’ enclosures are surrounded by 9 m tall adobe walls covered in relief patterns (Figure 2.14).
The Chimu civilisation was conquered by the Incas, whose monumental architecture utilised cut stone, although it is likely that the vernacular building continued in adobe.
The arrival of European settlers brought new building techniques from Europe, to develop
missions and settlements. In 1549 a Jesuit missionary sent a request to Europe to send ‘artisans able to handle soil, and carpenters, for the construction of a rammed earth wall’ for the construction of the Colégio da Campanhia in São Paulo. São Paulo became a focus of rammed earth building, with many monumental and vernacular buildings. The rammed earth cathedral of Taubaté was built in 1645, and the Church of Our Lady of the Rosary in 1720. Architectural styles followed those in southern Europe, and the rammed earth House of the
Chamber was built in 1776 in a style similar to that found in Portugal around the same time. In 1850 major flooding in São Paulo made many buildings unsafe, precipitating a public campaign against earth buildings, which led to the demolition of much of the historic earthen architecture. Building with adobe continues to be popular in many Andean parts of South America[20].
Figure 2.14: Chan Chan reliefs, Trujillo, Peru. Courtesy of Louise Davies
HISTORY OF EARTH BUILDING 25
2.9 AUSTRALASIA
Earth building is not used by the nomadic aboriginal people native to Australia, but European settlers experimented with a wide range of building techniques from their home countries. An early reference to rammed earth in Tasmania is given in the Hobart town gazette of May 1823:
“Resolved that the mode of building in Pise, or rammed earth, appearing to this Society to be both economical and expeditious, the Society earnestly recommend its adoption in Van Diemen’s Land”.
In 1839 the South Australian newspaper reported on 30 rammed earth houses being constructed, and rammed earth was often used as a quick construction technique in gold rush and frontier towns such as Penrith in New South Wales and Rushworth in Victoria. European settlers of New Zealand tried many forms of construction, including rammed earth and adobe,
but earthquakes in 1846 and 1855 meant that all forms of masonry fell out of favour. The best known historic earth monument in New Zealand is Pompallier House in Russell, built in 1841 (Figure 2.15)[20].
Rammed earth building in Australia was rediscovered by an English-trained architect, G F Middleton, who was employed by the Commonwealth Experimental Building Station.
Middleton conducted numerous tests that were written into the famous Bulletin No. 5 in 1953, which until recently was the accepted standard reference in Australia and New Zealand.
Earth building has recently developed in both Australia and New Zealand, with active national
bodies for the promotion of earth building.
Architects such as Graeme North in New Zealand and rammed earth contractors Stephen Dobson and Rick Lindsay in Australia have allowed earth building to flourish.
Figure 2.15: Pompallier House, Russell, New Zealand. Courtesy of Robert McClean
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2.10 CONCLUSIONS
In Chapter 1, we identified two aspects of earthen construction: monolithic and unit construction. Unit construction requires soils that are particularly rich in clay and silt: these are generally found in river valleys, and are usually combined with a binder material such as straw to produce small units. These units can be dried and carried short distances
away from the production site. As a result, the earliest large settlements using earthen construction materials, such as along the Tigris and Euphrates rivers, the settlement of Catalhöyük, and those of Harappa and Mohenjdaro along the Indus river, seem to have developed with settled agriculture, using the river valley soils combined with the cultivated crops now available. Conversely, where suitable soils were ubiquitous (such as softer loess soils), they can easily be excavated to produce piled and then rammed earth type structures. In western Asia the Lungshan culture and in North America
the Hokokam peoples developed piled and earth shelter building techniques.
As civilisation developed, the building material became of secondary importance to the architecture, and thus we find angled adobe bricks, such as at Huaca Pucllana in Lima or in the Drâa valleys of Morocco, or patterns cut into earth renders such as at Chan Chan in Peru. Rammed earth became decorated by the inclusion of decorative brick lines between each lift.
Earth has served as the construction material for many types of construction. Its primary use is usually vernacular construction, and the earliest settlements, such as those in the Indus valley, and around the Tigris and Euphrates rivers were able to grow because of the ubiquity of the construction material. Earth was used for the construction of large religious and memorial monuments such as the ziggurats in western Asia and the pyramids of the Sun and Moon in modern Peru, and those
in ancient Egypt before the stone construction.
Earth is particularly notable for its use in defensive constructions, particularly city walls. In China these walls are perhaps the largest, with the city walls of Xi’an and Beijing being around 20 m thick at the base. In the Himalayas, the walls surrounding Lo Manthang in Mustang are built in rammed earth, and in north Africa and southern Europe rammed earth was used for the city walls of many Islamic cites. The walls of Seville and Cordoba in Spain and Marrakech in Morocco are all constructed in rammed earth.
Although earth continued to be used as both a vernacular and a monumental construction material, its use declined over time as other construction materials become available, both through improved production processes (first for timber and stone, and later for steel and concrete) and through improved transportation methods. These, coupled with the improved mechanical properties that other materials exhibit, mean that earth began to fall out of use in some parts of the world.
By the 18th century, the industrial revolutions sweeping Europe and North America meant that other construction techniques could provide a viable alternative to earth building. Although earth building proved popular in the mid-west United States, the coming of the railways allowed more efficient construction techniques to develop.
Similarly, the development of Portland cement in 1824 and the use of iron and steel in construction pushed earth building away from mainstream construction.
Earth building in the developed world has recently seen a resurgence as a sustainable construction material. The virtues that made it so viable to early builders, namely low transport distances, simple construction processes and easy availability, make earth a potential ultimate sustainable construction material.
FUNDAMENTAL BEHAVIOUR OF EARTHEN CONSTRUCTION MATERIALS 27