Engineering
Beginnings
Architecture was born when people began to live in constructed dwellings and within communities. Caves were last used as habitats around 8000 BC.
Early engineering was centered around food. The development of tools and ways to increase the efficiency of farming and hunting were documented, first in cave paintings and later in Egypt with hieroglyphics.
Building Materials
The history of civil engineering and architectural projects is regional in nature.
The development of building design and construction on an African grassland differs greatly from building design and construction in Alaska or the mountainous regions of Peru.
A major reason for differences in the development of construction techniques is the availability of local materials. Although it is possible to import materials from great distances, the historic reality is that people often used what was easily available to them when constructing buildings.
This influenced architectural style and the selection of structural elements. Of course, climate also effects the design and construction of buildings. For example, sun dried bricks can support loads in a dry climate but will disintegrate in wet climates.
Materials were chosen based on availability and climate.
Ruins of Babylon (present day Iraq). All that remains of the famous city-state is a mound of broken mud-brick dwellings.
Current day Iraq consists mostly of alluvial plains – no stone, and wood is scarce. Sun-dried bricks (clay-rich soil mixed with straw) was used as early as the 4th millennium BC. The ruins of the famed city of Babylon illustrate the use of mud-bricks.
Materials were chosen based on availability and climate.
Greece consists almost entirely of limestone with many sources of fine marble. Therefore, many Greek structures were constructed with limestone and marble.
Materials were chosen based on availability and climate.
View of the city of Machu Picchu constructed from stone cut from the surrounding mountains.
The pre-Columbian Inca site of Machu Picchu sits on a mountain ridge in Peru.
The central buildings of Machu Picchu use the classic architectural style of dry-stone walls in which blocks of stone are cut to fit together tightly without mortar
Materials were chosen based on availability and climate.
Wood was readily available in China. Traditional Chinese wooden architecture changed little over thousands of years.
Because of their durability, examples of stone and brick buildings from past civilizations do exist. However, few examples of ancient buildings exist where less durable materials such as wood and grass were used.
In China and in Japan, most ancient buildings were constructed of wood (except for the tile roofs). Because wood tends to deteriorate over time, few examples of ancient Chinese buildings exist. However, the Chinese have long standardized uniform features of structures through manuals and drawings that were passed down for generations. Therefore, we can determine that Chinese architecture changed little over thousands of years.
Vernacular Architecture
Methods of construction that use locally available resources and traditions to address local needs.
Apache wickiup built of brush, grass, or reed
Traditional Nepalese house built of stone and clay
The Pyramids
The earliest large structures were the pyramids. Pyramids in Egypt were built as monuments to house the tombs of the pharaohs.
The Pyramids
The earliest know architect was Imhotep of (im HO tep) of Egypt. He was known for creating the first step pyramid at Sakkara (suh CAH ruh) around 2700 B.C.
This pyramid was a solid structure, but many early buildings were bearing wall types. Bearing walls are solid walls that provide support for each other and for the roof.
The building next to the pyramid in the right image illustrates a bearing wall system.
200 years later, the Great Pyramid of Khufu (KOO foo) was built. It is the largest masonry structure ever built.
The base measures 756 ft on each side and is 480 ft tall. The builder was Cheops (KEE ops), also known as Khufu.
His pyramid is the only surviving of the Seven Wonders of the Ancient World.
The Egyptians were not the only ones building pyramids.
In the Americas pyramids were built for religious ceremonies or scientific use.
This stepped pyramid in Yucatan, Mexico was built for astronomical purposes.
Modern Pyramids
Does anyone recognize this pyramid? Many modern pyramids exist, including this pyramid in the courtyard of the Louvre Museum in Paris, the Luxor hotel in Las Vegas, and the Pyramid Arena in Memphis, Tennessee.
Modern buildings are concerned with aesthetics as well as with functionality. Aesthetics is the quality of an object that deals with art, beauty, and taste.
The Parthenon
The Parthenon was built to house a statue of Athena, Greek goddess of war. Like other temples of its day, it was designed to be seen from the outside only.
The Parthenon is an example of post-and-lintel construction: horizontal beams placed across vertical posts.
This form of construction came about due to an early problem in architecture – how can door and window openings be provided in bearing walls without sacrificing support?
Post-and-lintel construction is an example of an early frame system.
The columns of the Parthenon are closely spaced because it is made of stone, which has little tensile capacity (unable to support wide openings).
Greek temples showed a change from wide columns to slender columns. Why this movement toward slenderness and greater intermediate spans? Although the main reason was aesthetics, the desire to reach greater heights and to bridge greater spans with less material cannot be ignored.
Arches
Supporting large openings was a major problem in the early design of structures.
Although very strong in compression, stone is weak in tension and cannot support the weight of the structure across a large openings.
The Romans developed the arch to overcome the limitations of the post and lintel.
An arch is a curved structure for spanning an opening, designed to support a vertical load primarily by axial compression.
Because they are made from smaller and lighter blocks of stone, they are easier to erect. Blocks are placed in a curved formation in such a way that they give each other support.
The wedge-shaped units in the arch are called voussoir (voo SWAR).
The keystone is the voussoir at the crown of the arch, serving to lock the others in place.
Can you think of some modern examples of the use of an arch?
The arch is often used in the construction of bridges, tunnels, sewers, and palaces.
The Vault
The development of the arch led to the vault, which is a series of arches that form a continuous arched covering.
When two of these vaults intersect, a cross vault is created. Another name for the cross vault is the groin vault. Vaults allow for the construction of bridges, walkways, and other passages.
What are some examples of vaults that you have seen? Most highway tunnels use the vault.
Domes
Another form that developed from the arch was the dome.
A dome is an arrangement of several arches whose bases form a circle and the tops meet in the center.
Can you think of other domes used in modern architecture?
Pantheon
The Pantheon is an example of an arch and dome system. It is the oldest standing domed structure in Rome.
Two amazing aspects of the Pantheon have to do with the materials used to create it.
The Pantheon's concrete was a mixture of volcanic ash, lime, and a small amount of water.
That mixture was packed, not poured, into place. Today we have Portland cement, a hydraulic cement that is a key ingredient in concrete and many other cementitious (SEE men TISH us) products such as masonry bricks and plaster.
Hydraulic cement hardens by reacting with water and is water-resistant.
Colosseum
Originally known as the Flavian Amphitheatre, this arch and dome system is the largest ever built in the Roman Empire.
It is considered by many to be one of the greatest works of Roman architecture and engineering.
Modern sports arenas are styled after the Colosseum, so named probably due to a colossal statue of Emperor Nero which is nearby.
Great Wall of China
The great wall is one of the most ambitious construction projects the world has ever seen.
It spans 4500 miles. Construction spanned from the 5th century BC to the 16th century.
The wall as seen today was mostly constructed during the Ming Dynasty of stone and bricks.
Water Supply
The need for a dependable water supply for domestic and agricultural purposes led to the construction of dams, canals, and aqueducts.
This usually involved conducting the water over long distances.
The engineering involved constructing the massive dams and solving problems associated with getting the water to flow to its destination.
Since water flows downhill, a combinations of canals, tunnels, and aqueducts were often required.
The Roman aqueducts were built from 300 BC to 200 AD.
These provided Rome with an ample supply of fresh water.
In the first century AD, almost 180 million gallons of water poured daily into Rome.
These aqueducts are another example of an arch and dome system.
Road Systems
Ancient roadways were used by the Persians and Romans for strategic and commercial purposes.
Greeks needed to have roads available in the event of a religious exodus. Greek highways consisted of two wheel ruts of about 4 ft 11 in. gauge either carved out or worn down.
The roads typically had a width of 8 or 9 feet and a depth of 3 to 4 inches. Sometimes this was increased to 12 inches to make the road smoother in the rocky ground. Urban streets were mostly paved.
Roman roads were created by using large blocks of stone (called the stratumen) for the base, over which broken stone or debris (called rudus) was spread and covered by a layer of sand (referred to as the nucleus) and finally by large polygonal basalt blocks (summum dorsum), with the polished top surfaces serving as the road surface.
The stones were set in lime mortar. In marshy regions the Romans used wooden causeways resting on pile foundations.
Romans were generally believed to be masters of road engineering. At the height of their power, they had constructed 50,000 miles of paved roads.
No comparable road system existed outside the Roman Empire. Overland lines of communication outside the Roman Empire consisted of beaten paths.
The cost of the roads was defrayed by public costs or private donations.
Augustus, for example, assigned roads to wealthy Senators who were responsible for their maintenance.
Early Bridge Designs
The earliest know Roman bridge, the Pons Sublicius in Rome, was made of wood and was constructed using columns and beams.
The pile foundation was created by following specific steps: excavate, clear, and then drive previously charred alder, olive, or oak piles into the ground as close to each other as possible.
The spaces were filled with ashes. The is an example of a timber bridge.
Most ancient Roman bridges used the arch as the basic structure and were typically made of stone and concrete.
Roman Bridges
A Roman bridge crosses the Afrin River in northern Syria and is still in use today.
Roman bridge in Vaison la Romaine,
South France.
After the Fall of Rome
The first arch bridge in the world to be made out of cast iron, a material which was previously far too expensive to use for large structures.
Although some jobs were mechanized, there was little change in building materials or methods of construction from those of the Romans until the middle of the 18th century.
The same simple cranes, pulley systems, wedges, and inclined planes were still commonly used to move heavy objects. The hammer, plane, and chisel were still the tools of choice of the carpenter.
However, in the middle of the 18th century, iron became cheaper and more readily available.
The first iron bridge was built over the Servern in 1779. A new blast furnace nearby lowered the cost and encouraged local engineers and architects to use iron to cross the river. The use of iron allowed longer spans and lighter structures.
What other materials do we have today that ancient architects and builders did not have?
Structural Steel
Perhaps the best-known structural steel framed building is the Empire State Building, completed in 1931.
Reinforced Concrete
The Burj Khalifa (United Arab Emirates) is the tallest man-made structure ever built. It is supported by a reinforced concrete core using a special concrete mix.
Reinforced Concrete
The concrete mixture used by the Romans was very weak in tension and bending.
Experiments with improving the tensile strength of concrete by embedding metal rods into the mixture began in the mid 1800s.
Eventually engineers learned how to efficiently take advantage of the combined strength of concrete in compression and steel in tension.
Since that time, reinforced concrete has been used for a variety of construction projects.
The flexibility of concrete allowed the use of free-flowing curves and a break from the rectilinear designs of structural steel.
Reinforced Concrete Bridges
Cedar Avenue Bridge (actually carrying Tenth Street) in Minneapolis, MN over the Mississippi is a reinforced concrete open spandrel arch bridge.
Reinforced Concrete Bridges
Engineers quickly understood that reinforced concrete could be used in the design and construction of bridges.
The first reinforced concrete bridge was built in France in 1907.
The Cedar Avenue Bridge in Minneapolis (shown) was completed in 1929 and is considered the crowning achievement of city engineer Dristoffer Olsen Oustad, who was involved in the design of several prominent structures in the area.
The bridge was added to the Register of Historic Places in 1989.