page_title: History of construction
section_title: The twentieth century
hierarchical_section_title: History of construction / The twentieth century
caption_attribution_description: English: Woolworth Building under construction.
context_page_description: The history of construction overlaps many other fields like structural engineering and relies on other branches of science like archaeology, history and architecture to investigate how the builders lived and recorded their accomplishments. Those fields allow us to analyse constructed buildings and other structures built since prehistory, the tools used and the different uses of building materials.
  History of building is evolving by different trends in time, marked by few key principles: durability of the materials used, the increasing of height and span, the degree of control exercised over the interior environment and finally the energy available to the construction process.
context_section_description: With the Second Industrial Revolution in the early 20th century, elevators and cranes made high rise buildings and skyscrapers possible, while heavy equipment and power tools decreased the workforce needed. Other new technologies were prefabrication and computer-aided design.
  Trade unions were formed to protect construction workers' interests and occupational safety and health. Personal protective equipment such as hard hats and earmuffs also came into use, and have become mandatory at most sites.
  From the 20th century, governmental construction projects were used as a part of macroeconomic stimulation policies, especially during the Great depression (see New Deal). For economy of scale, whole suburbs, towns and cities, including infrastructure, are often planned and constructed within the same project (called megaproject if the cost exceeds US$1 billion), such as Brasília in Brazil, and the Million Programme in Sweden.
  In the end of the 20th century, ecology, energy conservation and sustainable development have become more important issues of construction.
caption: Woolworth Building under construction in 1912
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