Reinforced concrete in the context of "Rebar"

Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactured material in the world.

When aggregate is mixed with dry Portland cement and water, the mixture forms a fluid slurry that can be poured and molded into shape. The cement reacts with the water through a process called hydration, which hardens it after several hours to form a solid matrix that binds the materials together into a durable stone-like material with various uses. This time allows concrete to not only be cast in forms, but also to have a variety of tooled processes performed. The hydration process is exothermic, which means that ambient temperature plays a significant role in how long it takes concrete to set. Often, additives (such as pozzolans or superplasticizers) are included in the mixture to improve the physical properties of the wet mix, delay or accelerate the curing time, or otherwise modify the finished material. Most structural concrete is poured with reinforcing materials (such as steel rebar) embedded to provide tensile strength, yielding reinforced concrete.

The history of architecture traces the changes in architecture through various traditions, regions, overarching stylistic trends, and dates. The beginnings of all these traditions is thought to be humans satisfying the very basic need of shelter and protection. The term "architecture" generally refers to buildings, but in its essence is much broader, including fields we now consider specialized forms of practice, such as urbanism, civil engineering, naval, military, and landscape architecture.

Trends in architecture were influenced, among other factors, by technological innovations, particularly in the 19th, 20th and 21st centuries. The improvement and/or use of steel, cast iron, tile, reinforced concrete, and glass helped for example Art Nouveau appear and made Beaux Arts more grandiose.

Building material is material used for construction. Many naturally occurring substances, such as clay, rocks, sand, wood, and even twigs and leaves, have been used to construct buildings and other structures, like bridges. Apart from naturally occurring materials, many man-made products are in use, some more and some less synthetic. The manufacturing of building materials is an established industry in many countries and the use of these materials is typically segmented into specific specialty trades, such as carpentry, insulation, plumbing, and roofing work. They provide the make-up of habitats and structures including homes.

A skyscraper is a tall building with many habitable floors. Most modern sources define skyscrapers as being at least 100 metres (330 ft) or 150 metres (490 ft) in height, though there is no universally accepted definition, other than being very tall high-rise buildings. Skyscrapers may host offices, hotels, residential spaces, and retail spaces. Skyscrapers are a common feature of large cities, often due to a high demand for space and limited availability of land.

One common feature of skyscrapers is having a steel frame that supports curtain walls. These curtain walls either bear on the framework below or are suspended from the framework above, rather than resting on load-bearing walls of conventional construction. Some early skyscrapers have a steel frame that enables the construction of load-bearing walls taller than those made of reinforced concrete. Modern skyscraper walls are not load-bearing, and most skyscrapers are characterized by large surface areas of windows made possible by steel frames and curtain walls. However, skyscrapers can have curtain walls that mimic conventional walls with a small surface area of windows. Modern skyscrapers often have a tubular structure, and are designed to act like a hollow cylinder to resist wind, seismic, and other lateral loads. To appear more slender, allow less wind exposure and transmit more daylight to the ground, many skyscrapers have a design with setbacks, which in some cases is also structurally required.

Christ the Redeemer (Portuguese: Cristo Redentor, standard Brazilian Portuguese: [ˈkɾistu ʁedẽˈtoʁ]) is an Art Deco statue of Jesus in Rio de Janeiro, Brazil, created by French-Polish sculptor Paul Landowski and built by Brazilian engineer Heitor da Silva Costa, in collaboration with French engineer Albert Caquot. Romanian sculptor Gheorghe Leonida sculpted the face. Constructed between 1922 and 1931, the statue is 30 metres (98 ft) high, excluding its 8-metre (26 ft) pedestal. The arms stretch 28 metres (92 ft) wide. It is made of reinforced concrete and soapstone. Christ the Redeemer differs considerably from its original design, as the initial plan was a large Christ with a globe in one hand and a cross in the other. Although the project organizers originally accepted the design, it later changed to the statue of today, with the arms spread out wide.

The statue weighs 635 metric tons (625 long, 700 short tons), and is located at the peak of the 700-metre (2,300 ft) Corcovado mountain in the Tijuca National Park overlooking the city of Rio de Janeiro. This statue is the largest Art Deco–style sculpture in the world. A symbol of Christianity around the world, the statue has also become a cultural icon of both Rio de Janeiro and Brazil and was voted one of the New 7 Wonders of the World.

Oscar Ribeiro de Almeida Niemeyer Soares Filho (15 December 1907 – 5 December 2012), known as Oscar Niemeyer (Brazilian Portuguese: [ˈoskaʁ ni.eˈmajeʁ]), was a Brazilian architect considered to be one of the key figures in the development of modern architecture. Niemeyer was best known for his design of civic buildings for Brasília, a planned city that became Brazil's capital in 1960, as well as his collaboration with other architects on the headquarters of the United Nations in New York. His exploration of the aesthetic possibilities of reinforced concrete was highly influential in the late 20th and early 21st centuries.

Both lauded and criticized for being a "sculptor of monuments", Niemeyer was hailed as a great artist and one of the greatest architects of his generation by his supporters. He said his architecture was strongly influenced by Le Corbusier, but in an interview, assured that this "didn't prevent [his] architecture from going in a different direction". Niemeyer was most famous for his use of abstract forms and curves and wrote in his memoirs:

Beam bridges are the simplest structural forms for bridge spans supported by an abutment or pier at each end. No moments are transferred throughout the support, hence their structural type is known as simply supported.

The simplest beam bridge could be a log (see log bridge), a wood plank, or a stone slab (see clapper bridge) laid across a stream. Bridges designed for modern infrastructure will usually be constructed of steel or reinforced concrete, or a combination of both. The concrete elements may be reinforced or prestressed. Such modern bridges include girder, plate girder, and box girder bridges, all types of beam bridges.

A cable-stayed bridge is a type of bridge that has one or more towers (or pylons), from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern or a series of parallel lines. This is in contrast to the modern suspension bridge, where the cables supporting the deck are suspended vertically from the main cables, which run between the towers and are anchored at both ends of the bridge. The cable-stayed bridge is optimal for spans longer than cantilever bridges and shorter than suspension bridges. This is the range within which cantilever bridges would rapidly grow heavier, and suspension bridge cabling would be more costly.

Cable-stayed bridges found wide use in the late 19th century. Early examples, including the Brooklyn Bridge, often combined features from both the cable-stayed and suspension designs. Cable-stayed designs fell from favor in the early 20th century as larger gaps were bridged using pure suspension designs, and shorter ones using various systems built of reinforced concrete. It returned to prominence in the later 20th century when the combination of new materials, larger construction machinery, and the need to replace older bridges all lowered the relative price of these designs.