Construction

Construction is the process of constructing a building or infrastructure.[1] Construction differs from manufacturing in that manufacturing typically involves mass production of similar items without a designated purchaser, while construction typically takes place on location for a known client.[2] Construction as an industry comprises six to nine percent of the gross domestic product of developed countries.[3] Construction starts with planning, design, and financing; it continues until the project is built and ready for use.

Large-scale construction requires collaboration across multiple disciplines. A project manager normally manages the job, and a construction manager, design engineer, construction engineer or architect supervises it. Those involved with the design and execution must consider zoning requirements, environmental impact of the job, scheduling, budgeting, construction-site safety, availability and transportation of building materials, logistics, inconvenience to the public caused by construction delays and bidding. Large construction projects are sometimes referred to as megaprojects.

Sky scraper construction
In large construction projects, such as this skyscraper in Melbourne, Australia, cranes are essential
Construction site in Cologne, Germany (2017)
Construction site and equipment prepared for start of work in Cologne, Germany (2017)

Etymology

Construction is a general term meaning the art and science to form objects, systems, or organizations,[4] and comes from Latin constructio (from com- "together" and struere "to pile up") and Old French construction.[5] To construct is the verb: the act of building, and the noun construction: how a building was built, the nature of its structure.

Types

Industrial-installation
Industrial assemblage of a thermal oxidizer in the United States of America

In general, there are three sectors of construction: buildings, infrastructure and industrial.[6] Building construction is usually further divided into residential and non-residential (commercial/institutional). Infrastructure is often called heavy civil or heavy engineering that includes large public works, dams, bridges, highways, railways, water or wastewater and utility distribution. Industrial construction includes refineries, process chemical, power generation, mills and manufacturing plants. There are also other ways to break the industry into sectors or markets.[7]

Industry sectors

US Navy 080629-N-6477M-095 Builder 3rd Class Merlyna Crank and Builder Constructionman Irene L. Reeves, both assigned to Naval Mobile Construction Battalion (NMCB) 3 Det. 4, place trimming on birthing spaces being built for Afg
Military residential unit construction by U.S. Navy personnel in Afghanistan
Tijuana residential construction
Construction workers working on a residential building in Tijuana, Mexico

Engineering News-Record (ENR), a trade magazine for the construction industry, each year compiles and reports data about the size of design and construction companies. In 2014, ENR compiled the data in nine market segments divided as transportation, petroleum, buildings, power, industrial, water, manufacturing, sewer/waste, telecom, hazardous waste and a tenth category for other projects.[8] In their reporting, they used data on transportation, sewer, hazardous waste and water to rank firms as heavy contractors.[9]

The Standard Industrial Classification and the newer North American Industry Classification System have a classification system for companies that perform or engage in construction. To recognize the differences of companies in this sector, it is divided into three subsectors: building construction, heavy and civil engineering construction, and specialty trade contractors. There are also categories for construction service firms (e.g., engineering, architecture) and construction managers (firms engaged in managing construction projects without assuming direct financial responsibility for completion of the construction project).[10][11]

Building construction

Building construction is the process of adding structure to real property or construction of buildings. The majority of building construction jobs are small renovations, such as addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster, and design team for the entire project.[12] Although building construction projects consist of common elements such as design, financial, estimating and legal considerations, projects of varying sizes may reach undesirable end results, such as structural collapse, cost overruns, and/or litigation. For this reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome.

Factory of National Cement Share Company
The National Cement Share Company of Ethiopia's new plant in Dire Dawa

Commercial building construction is procured privately or publicly utilizing various delivery methodologies, including cost estimating, hard bid, negotiated price, traditional, management contracting, construction management-at-risk, design & build and design-build bridging.

Residential construction practices, technologies, and resources must conform to local building authority regulations and codes of practice. Materials readily available in the area generally dictate the construction materials used (e.g. brick versus stone, versus timber). Cost of construction on a per square meter (or per square foot) basis for houses can vary dramatically based on site conditions, local regulations, economies of scale (custom designed homes are often more expensive to build) and the availability of skilled tradesmen. Residential construction as well as other types of construction can generate waste such that planning is required.

According to McKinsey research, productivity growth per worker in construction has lagged behind many other industries across different countries including in the United States and in European countries. In the United States, construction productivity per worker has declined by half since the 1960s.[13]

Residential construction

Ladder fall prevention (9253630705)
Framing

The most popular method of residential construction in North America is wood-framed construction. Typical construction steps for a single-family or small multi-family house are:

  • Obtain an engineered soil test of lot where construction is planned. From an engineer or company specializing in soil testing.
  • Develop floor plans and obtain a materials list for estimations (more recently performed with estimating software)
  • Obtain structural engineered plans for foundation and structure. To be completed by either a licensed engineer or architect. To include both a foundation and framing plan.
  • Obtain lot survey
  • Obtain government building approval if necessary
  • If required obtain approval from HOA (homeowners association) or ARC (architectural review committee)
  • Clear the building site (demolition of existing home if necessary)
  • Survey to stake out for the foundation
  • Excavate the foundation and dig footers (Scope of work is dependent of foundation designed by engineer)
  • Install plumbing grounds
  • Pour a foundation and footers with concrete
  • Build the main load-bearing structure out of thick pieces of wood and possibly metal I-beams for large spans with few supports. See framing (construction)
  • Add floor and ceiling joists and install subfloor panels
  • Cover outer walls and roof in OSB or plywood and a water-resistive barrier.
  • Install roof shingles or other covering for flat roof
  • Cover the walls with siding, typically vinyl, wood, or brick veneer but possibly stone or other materials
  • Install windows
  • Frame interior walls with wooden 2×4s
  • Add internal plumbing, HVAC, electrical, and natural gas utilities
  • Building inspector visits if necessary to approve utilities and framing
  • Install insulation and interior drywall panels (cementboard for wet areas) and to complete walls and ceilings
  • Install bathroom fixtures
  • Spackle, prime, and paint interior walls and ceilings
  • Additional tiling on top of cementboard for wet areas, such as the bathroom and kitchen backsplash
  • Installation of final floor covering, such as floor tile, carpet, or wood flooring
  • Installation of major appliances
  • Unless the original owners are building the house, at this point it is typically sold or rented.

Processes

Shasta dam under construction new edit
Shasta Dam under construction in June 1942

Design team

In the industrialized world, construction usually involves the translation of designs into reality. A formal design team may be assembled to plan the physical proceedings, and to integrate those proceedings with the other parts. The design usually consists of drawings and specifications, usually prepared by a design team including architect, civil engineers, mechanical engineers, electrical engineers, structural engineers, fire protection engineers, planning consultants, architectural consultants, and archaeological consultants. The design team is most commonly employed by (i.e. in contract with) the property owner. Under this system, once the design is completed by the design team, a number of construction companies or construction management companies may then be asked to make a bid for the work, either based directly on the design, or on the basis of drawings and a bill of quantities provided by a quantity surveyor. Following evaluation of bids, the owner typically awards a contract to the most cost efficient bidder.

The best modern trend in design is toward integration of previously separated specialties, especially among large firms. In the past, architects, interior designers, engineers, developers, construction managers, and general contractors were more likely to be entirely separate companies, even in the larger firms. Presently, a firm that is nominally an "architecture" or "construction management" firm may have experts from all related fields as employees, or to have an associated company that provides each necessary skill. Thus, each such firm may offer itself as "one-stop shopping" for a construction project, from beginning to end. This is designated as a "design build" contract where the contractor is given a performance specification and must undertake the project from design to construction, while adhering to the performance specifications.[14]

Several project structures can assist the owner in this integration, including design-build, partnering and construction management. In general, each of these project structures allows the owner to integrate the services of architects, interior designers, engineers and constructors throughout design and construction. In response, many companies are growing beyond traditional offerings of design or construction services alone and are placing more emphasis on establishing relationships with other necessary participants through the design-build process.

The increasing complexity of construction projects creates the need for design professionals trained in all phases of the project's life-cycle and develop an appreciation of the building as an advanced technological system requiring close integration of many sub-systems and their individual components, including sustainability. Building engineering is an emerging discipline that attempts to meet this new challenge.

Financial advisors

Trump International Hotel and Tower, Chicago (0837)
May 23, 2006
20070914 Trump International Hotel & Tower - Chicago
September 14, 2007 (3 months before completion)

Construction projects can suffer from preventable financial problems. Underbids happen when builders ask for too little money to complete the project. Cash flow problems exist when the present amount of funding cannot cover the current costs for labour and materials, and because they are a matter of having sufficient funds at a specific time, can arise even when the overall total is enough. Fraud is a problem in many fields, but is notoriously prevalent in the construction field.[15] Financial planning for the project is intended to ensure that a solid plan with adequate safeguards and contingency plans are in place before the project is started and is required to ensure that the plan is properly executed over the life of the project.

Mortgage bankers, accountants, and cost engineers are likely participants in creating an overall plan for the financial management of the building construction project. The presence of the mortgage banker is highly likely, even in relatively small projects since the owner's equity in the property is the most obvious source of funding for a building project. Accountants act to study the expected monetary flow over the life of the project and to monitor the payouts throughout the process. Cost engineers and estimators apply expertise to relate the work and materials involved to a proper valuation. Cost overruns with government projects have occurred when the contractor identified change orders or project changes that increased costs, which are not subject to competition from other firms as they have already been eliminated from consideration after the initial bid.[16]

Large projects can involve highly complex financial plans and often start with a conceptual estimate performed by a building estimator. As portions of a project are completed, they may be sold, supplanting one lender or owner for another, while the logistical requirements of having the right trades and materials available for each stage of the building construction project carries forward. In many English-speaking countries, but not the United States, projects typically use quantity surveyors.

Legal aspects

401-403-410 and Construction crop
Construction along Ontario Highway 401, widening the road from six to twelve travel lanes

A construction project must fit into the legal framework governing the property. These include governmental regulations on the use of property, and obligations that are created in the process of construction.

When applicable, the project must adhere to zoning and building code requirements. Constructing a project that fails to adhere to codes does not benefit the owner. Some legal requirements come from malum in se considerations, or the desire to prevent indisputably bad phenomena, e.g. explosions or bridge collapses. Other legal requirements come from malum prohibitum considerations, or factors that are a matter of custom or expectation, such as isolating businesses from a business district or residences from a residential district. An attorney may seek changes or exemptions in the law that governs the land where the building will be built, either by arguing that a rule is inapplicable (the bridge design will not cause a collapse), or that the custom is no longer needed (acceptance of live-work spaces has grown in the community).[17]

A construction project is a complex net of contracts and other legal obligations, each of which all parties must carefully consider. A contract is the exchange of a set of obligations between two or more parties, but it is not so simple a matter as trying to get the other side to agree to as much as possible in exchange for as little as possible. The time element in construction means that a delay costs money, and in cases of bottlenecks, the delay can be extremely expensive. Thus, the contracts must be designed to ensure that each side is capable of performing the obligations set out. Contracts that set out clear expectations and clear paths to accomplishing those expectations are far more likely to result in the project flowing smoothly, whereas poorly drafted contracts lead to confusion and collapse.

Legal advisors in the beginning of a construction project seek to identify ambiguities and other potential sources of trouble in the contract structure, and to present options for preventing problems. Throughout the process of the project, they work to avoid and resolve conflicts that arise. In each case, the lawyer facilitates an exchange of obligations that matches the reality of the project.

Interaction of expertise

UnderConstruction-Apt
Apartment complex under construction in Daegu, South Korea

Design, finance, and legal aspects overlap and interrelate. The design must be not only structurally sound and appropriate for the use and location, but must also be financially possible to build, and legal to use. The financial structure must accommodate the need for building the design provided, and must pay amounts that are legally owed. The legal structure must integrate the design into the surrounding legal framework, and enforce the financial consequences of the construction process.

Procurement

Procurement describes the merging of activities undertaken by the client to obtain a building. There are many different methods of construction procurement; however, the three most common types of procurement are traditional (design–bid–build), design-build and management contracting.[18]

There is also a growing number of new forms of procurement that involve relationship contracting where the emphasis is on a co-operative relationship among the principal, the contractor, and other stakeholders within a construction project. New forms include partnering such as Public-Private Partnering (PPPs) aka private finance initiatives (PFIs) and alliances such as "pure" or "project" alliances and "impure" or "strategic" alliances. The focus on co-operation is to ameliorate the many problems that arise from the often highly competitive and adversarial practices within the construction industry.

Traditional

This is the most common method of construction procurement, and it is well-established and recognized. In this arrangement, the architect or engineer acts as the project coordinator. His or her role is to design the works, prepare the specifications and produce construction drawings, administer the contract, tender the works, and manage the works from inception to completion. There are direct contractual links between the architect's client and the main contractor. Any subcontractor has a direct contractual relationship with the main contractor. The procedure continues until the building is ready to occupy.

Design-build

Construction of the Phase-1 (first two towers) of the
Havelock City Project, Sri Lanka

Havelock City, Sri Lanka, 003
Havelock City, Sri Lanka, 004

This approach has become more common in recent years, and also involves the client contracting a single entity that both provides a design and builds it. In some cases, the design-build package can also include finding the site, arranging funding and applying for all necessary statutory consents.

The owner produces a list of requirements for a project, giving an overall view of the project's goals. Several D&B contractors present different ideas about how to accomplish these goals. The owner selects the ideas they like best and hires the appropriate contractor. Often, it is not just one contractor, but a consortium of several contractors working together. Once these have been hired, they begin building the first phase of the project. As they build phase 1, they design phase 2. This is in contrast to a design-bid-build contract, where the project is completely designed by the owner, then bid on, then completed.

Kent Hansen pointed out that state departments of transportation usually use design build contracts as a way of progressing projects when states lack the skills-resources. In such departments, design build contracts are usually employed for very large projects.[19]

Management procurement systems

In this arrangement the client plays an active role in the procurement system by entering into separate contracts with the designer (architect or engineer), the construction manager, and individual trade contractors. The client takes on the contractual role, while the construction or project manager provides the active role of managing the separate trade contracts, and ensuring that they complete all work smoothly and effectively together.

Management procurement systems are often used to speed up the procurement processes, allow the client greater flexibility in design variation throughout the contract, give the ability to appoint individual work contractors, separate contractual responsibility on each individual throughout the contract, and to provide greater client control.

In recent time, construction software starts to get traction—as it digitizes construction industry. Among solutions, there are for example: Procore, GenieBelt, PlanGrid, bouw7, etc.

Sustainability in construction

Sustainability during the construction phase is one of the aspects of “green building," defined by the United States Environmental Protection Agency (EPA) as "the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle from siting to design, construction, operation, maintenance, renovation and deconstruction."[20]

Authority having jurisdiction

Mall culture jakarta57
Digging the foundation for a building construction in Jakarta, Indonesia

In construction, the authority having jurisdiction (AHJ) is the governmental agency or sub-agency that regulates the construction process. In most cases, this is the municipality where the building is located. However, construction performed for supra-municipal authorities are usually regulated directly by the owning authority, which becomes the AHJ.

Liberty Memorial 043
Construction on the Federal Reserve building in Kansas City, Missouri

Before the foundation can be dug, contractors are typically required to verify and have existing utility lines marked, either by the utilities themselves or through a company specializing in such services. This lessens the likelihood of damage to the existing electrical, water, sewage, phone, and cable facilities, which could cause outages and potentially hazardous situations. During the construction of a building, the municipal building inspector inspects the building periodically to ensure that the construction adheres to the approved plans and the local building code. Once construction is complete and a final inspection has been passed, an occupancy permit may be issued.

An operating building must remain in compliance with the fire code. The fire code is enforced by the local fire department or a municipal code enforcement office.

Changes made to a building that affect safety, including its use, expansion, structural integrity, and fire protection items, usually require approval of the AHJ for review concerning the building code.

Industry characteristics

In the United States, the industry in 2014 has around $960 billion in annual revenue according to statistics tracked by the Census Bureau, of which $680 billion is private (split evenly between residential and nonresidential) and the remainder is government.[21] In 2005, there were about 667,000 firms employing 1 million contractors (200,000 general contractors, 38,000 heavy, and 432,000 specialty); the average contractor employed fewer than 10 employees.[22] As a whole, the industry employed an estimated 5.8 million in April 2013, with a 13.2% unemployment rate.[23] In the United States, approximately 828,000 women were employed in the construction industry as of 2011.[24]

Careers

European Antennas Under Construction
Helicopter view of the Atacama Large Millimeter/submillimeter Array (ALMA) Operations Support Facility (OSF) construction site
Construction Workers
Ironworkers erecting the steel frame of a new building at Massachusetts General Hospital in Boston
Algamildj.jpeg
A truck operator at Al Gamil, the largest construction company in Djibouti.

There are many routes to the different careers within the construction industry. These three main tiers are based on educational background and training, which vary by country:

  • Unskilled and semi-skilled – General site labor with little or no construction qualifications.
  • Skilled – Tradesmen who've served apprenticeships, typically in labor unions, and on-site managers who possess extensive knowledge and experience in their craft or profession.
  • Technical and management – Personnel with the greatest educational qualifications, usually graduate degrees, trained to design, manage and instruct the construction process.

Skilled occupations include carpenters, electricians, plumbers, ironworkers, masons, and many other manual crafts, as well as those involved in project management. In the UK these require further education qualifications, often in vocational subject areas. These qualifications are either obtained directly after the completion of compulsory education or through "on the job" apprenticeship training.[25] In the UK, 8500 construction-related apprenticeships were commenced in 2007.[26]

Technical and specialized occupations require more training as a greater technical knowledge is required. These professions also hold more legal responsibility. A short list of the main careers with an outline of the educational requirements are given below:

In 2010 a salary survey revealed the differences in remuneration between different roles, sectors and locations in the construction and built environment industry.[27] The results showed that areas of particularly strong growth in the construction industry, such as the Middle East, yield higher average salaries than in the UK, for example. The average earning for a professional in the construction industry in the Middle East, across all sectors, job types and levels of experience, is £42,090, compared to £26,719 in the UK.[28] This trend is not necessarily due to the fact that more affluent roles are available; however, as architects with 14 or more years' experience working in the Middle East earn on average £43,389 per annum, compared to £40,000 in the UK.[28] Some construction workers in the US/Canada have made more than $100,000 annually, depending on their trade.[29]

Safety

Construction workers not wearing fall protection equipment
At-risk workers without appropriate safety equipment

Construction is one of the most dangerous occupations in the world, incurring more occupational fatalities than any other sector in both the United States and in the European Union.[30][31] In 2009, the fatal occupational injury rate among construction workers in the United States was nearly three times that for all workers, with Falls being one of the most common causes of fatal and non-fatal injuries among construction workers.[30] Proper safety equipment such as harnesses, hard hats and guardrails and procedures such as securing ladders and inspecting scaffolding can curtail the risk of occupational injuries in the construction industry.[32] Other major causes of fatalities in the construction industry include electrocution, transportation accidents, and trench cave-ins.[33]

Roofing-2
Roofing requires a very high level of safety

Other safety risks for workers in construction include hearing loss due to high noise exposure, musculoskeletal injury, chemical exposure, and high levels of stress.[24] Besides that, the high turnover of workers in construction industry imposes a huge challenge of accomplishing the restructuring of work practices in individual workplaces or with individual workers. Construction has been identified by the National Institute for Occupational Safety and Health (NIOSH) as a priority industry sector in the National Occupational Research Agenda (NORA) to identify and provide intervention strategies regarding occupational health and safety issues.[34][35]

History

The first huts and shelters were constructed by hand or with simple tools. As cities grew during the Bronze Age, a class of professional craftsmen, like bricklayers and carpenters, appeared. Occasionally, slaves were used for construction work. In the Middle Ages, the artisan craftsmen were organized into guilds. In the 19th century, steam-powered machinery appeared, and, later, diesel- and electric-powered vehicles such as cranes, excavators and bulldozers.

Fast-track construction has been increasingly popular in the 21st century. Some estimates suggest that 40% of construction projects are now fast-track construction.[36]

Construction output by country

List of countries with the largest construction output in 2015
Economy
Construction output in 2015 (billions in USD)
(01)  China
1,849
(02)  United States
599
(03)  Japan
569
(04)  India
333
(05)  France
147
(06)  Germany
143
(07)  Singapore
131
(08)  Canada
131
(09)  Australia
115
(10)  Russia
111
(11)  Brazil
109
(12)  Italy
107
(13)  Spain
104
(14)  Indonesia
93
(15)  Mexico
92
(16)  South Korea
58
(17)  Turkey
35
(18)  United Arab Emirates
34
(19)  Venezuela
34
(20)  Netherlands
34
(21)  Poland
34
(22)   Switzerland
33
(23)  Saudi Arabia
32
(24)  Iran
29
(25)  Colombia
29

The twenty-five largest countries in the world by construction output (2012)[37]

See also

References

  1. ^ Compare: "Construction", Merriam-Webster.com, Merriam-Webster, retrieved 2016-02-16, [...] the act or process of building something (such as a house or road) [...].
  2. ^ Halpin, Daniel W.; Senior, Bolivar A. (2010), Construction Management (4 ed.), Hoboken, NJ: John Wiley & Sons, p. 9, ISBN 9780470447239, retrieved May 16, 2015
  3. ^ Chitkara, K. K. (1998), Construction Project Management, New Delhi: Tata McGraw-Hill Education, p. 4, ISBN 9780074620625, retrieved May 16, 2015
  4. ^ "Construction" def. 1.a. 1.b. and 1.c. Oxford English Dictionary Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009
  5. ^ "Construction". Online Etymology Dictionary http://www.etymonline.com/index.php?term=construction accessed 3/6/2014
  6. ^ Chitkara, pp. 9–10.
  7. ^ Halpin, pp. 15–16.
  8. ^ "The Top 250", Engineering News-Record, September 1, 2014
  9. ^ "The Top 400" (PDF), Engineering News-Record, May 26, 2014
  10. ^ US Census Bureau,NAICS Search 2012 NAICS Definition, Sector 23 – Construction
  11. ^ US Department of Labor (OSHA), Division C: Construction
  12. ^ "The Subaru Headquarters Construction Site", Engineering News-Record, October 20, 2016
  13. ^ "The construction industry's productivity problem". The Economist. Retrieved 2017-08-21.
  14. ^ Dynybyl, Vojtěch; Berka, Ondrej; Petr, Karel; Lopot, František; Dub, Martin (2015-12-09). The Latest Methods of Construction Design. Springer. ISBN 9783319227627.
  15. ^ "Global construction industry faces growing threat of economic crime". pwc. pwc. Retrieved 16 September 2015.
  16. ^ "North County News – San Diego Union Tribune". www.nctimes.com.
  17. ^ Mason, Jim (2016-04-14). Construction Law: From Beginner to Practitioner. Routledge. ISBN 9781317391777.
  18. ^ Mosey, David (2019-05-20). Collaborative Construction Procurement and Improved Value. John Wiley & Sons. ISBN 9781119151913.
  19. ^ Cronin, Jeff (2005). "S. Carolina Court to Decide Legality of Design-Build Bids". Construction Equipment Guide. Retrieved 2008-01-04.
  20. ^ "Basic Information | Green Building |US EPA". archive.epa.gov. Retrieved 2018-12-11.
  21. ^ Value of Construction Put in Place at a Glance. United States Census Bureau. Also see Manufacturing & Construction Statistics for more information.
  22. ^ McIntyre M, Strischek D. (2005). Surety Bonding in Today's Construction Market: Changing Times for Contractors, Bankers, and Sureties. The RMA Journal.
  23. ^ Industries at a Glance: Construction: NAICS 23. U.S. Bureau of Labor Statistics.
  24. ^ a b Swanson, Naomi; Tisdale-Pardi, Julie; MacDonald, Leslie; Tiesman, Hope M. (13 May 2013). "Women's Health at Work". National Institute for Occupational Safety and Health. Retrieved 21 January 2015.
  25. ^ Wood, Hannah (17 January 2012). "UK Construction Careers, Certifications/Degrees and occupations". TH Services. Archived from the original on 4 March 2012. Retrieved 4 March 2012.
  26. ^ "CITB Apprenticeships - CITB". www.cskills.org.
  27. ^ "UK website launches salary comparison tool". Retrieved 2011-07-04.
  28. ^ a b "Salary Benchmarker". Retrieved 2011-07-04.
  29. ^ Fottrell, Quentin. "5 blue-collar jobs that pay $100,000 a year". MarketWatch. Retrieved 2019-04-21.
  30. ^ a b "Construction Safety and Health". Workplace Safety & Health Topics. National Institute of Occupational Safety and Health. Retrieved 3 August 2012.
  31. ^ "Health and safety at work statistics". eurostat. European Commission. Retrieved 3 August 2012.
  32. ^ "OSHA's Fall Prevention Campaign". Occupational Safety and Health Administration. Retrieved 6 August 2012.
  33. ^ "The Construction Chart Book: The US Construction Industry and its Workers" (PDF). CPWR, 2013.
  34. ^ "CDC - NIOSH Program Portfolio : Construction Program". www.cdc.gov. 2018-04-05. Retrieved 2018-04-07.
  35. ^ "CDC - NIOSH - NORA Construction Sector Council". www.cdc.gov. 2017-12-01. Retrieved 2018-04-07.
  36. ^ Knecht B. Fast-track construction becomes the norm. Architectural Record.
  37. ^ Figures from the United Nations' UN National Accounts Database. for the countries of the world. Retrieved 1 February 2014.
Architect

An architect is a person who plans, designs and reviews the construction of buildings. To practice architecture means to provide services in connection with the design of buildings and the space within the site surrounding the buildings that have human occupancy or use as their principal purpose. Etymologically, architect derives from the Latin architectus, which derives from the Greek (arkhi-, chief + tekton, builder), i.e., chief builder.Professionally, an architect's decisions affect public safety, and thus an architect must undergo specialized training consisting of advanced education and a practicum (or internship) for practical experience to earn a license to practice architecture. Practical, technical, and academic requirements for becoming an architect vary by jurisdiction.

Burj Khalifa

The Burj Khalifa (Arabic: برج خليفة‎, Arabic for "Khalifa Tower"; pronounced English: ), known as the Burj Dubai prior to its inauguration in 2010, is a skyscraper in Dubai, United Arab Emirates. With a total height of 829.8 m (2,722 ft) and a roof height (excluding antenna) of 828 m (2,717 ft), the Burj Khalifa has been the tallest structure and building in the world since its topping out in 2009.Construction of the Burj Khalifa began in 2004, with the exterior completed five years later in 2009. The primary structure is reinforced concrete. The building was opened in 2010 as part of a new development called Downtown Dubai. It is designed to be the centrepiece of large-scale, mixed-use development. The decision to construct the building is based on the government's decision to diversify from an oil-based economy, and for Dubai to gain international recognition. The building was originally named Burj Dubai but was renamed in honour of the ruler of Abu Dhabi and president of the United Arab Emirates, Khalifa bin Zayed Al Nahyan; Abu Dhabi and the UAE government lent Dubai money to pay its debts. The building broke numerous height records, including its designation as the tallest building in the world.

Burj Khalifa was designed by Adrian Smith, of Skidmore, Owings & Merrill, whose firm designed the Willis Tower and One World Trade Center. Hyder Consulting was chosen to be the supervising engineer with NORR Group Consultants International Limited chosen to supervise the architecture of the project. The design is derived from the Islamic architecture of the region, such as in the Great Mosque of Samarra. The Y-shaped tripartite floor geometry is designed to optimize residential and hotel space. A buttressed central core and wings are used to support the height of the building. Although this design was derived from Tower Palace III, the Burj Khalifa's central core houses all vertical transportation with the exception of egress stairs within each of the wings. The structure also features a cladding system which is designed to withstand Dubai's hot summer temperatures. It contains a total of 57 elevators and 8 escalators.

At a certain point in the architectural and engineering process, the original Emaar developers ran into financial issues, and required more money and economic funding. Sheikh Khalifa, the ruler of the United Arab Emirates, granted monetary aid and funding, hence resulting in the changing of the name to "Burj Khalifa". The concept of profitability derived from building high density developments and malls around the landmark have proven successful. Its surrounding malls, hotels and condominiums in Downtown Dubai have generated the most revenue from the project as a whole, while the Burj Khalifa itself made little or no profit.Critical reception to Burj Khalifa has been generally positive, and the building has received many awards. There were complaints concerning migrant workers from South Asia who were the primary building labor force. These centered on low wages and the practice of confiscating passports until duties were complete. Several suicides were reported.

Civil engineering

Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewerage systems, pipelines, structural components of buildings, and railways.Civil engineering is traditionally broken into a number of sub-disciplines. It is considered the second-oldest engineering discipline after military engineering, and it is defined to distinguish non-military engineering from military engineering. Civil engineering takes place in the public sector from municipal through to national governments, and in the private sector from individual homeowners through to international companies.

General contractor

A general contractor, main contractor or prime contractor is responsible for the day-to-day oversight of a construction site, management of vendors and trades, and the communication of information to all involved parties throughout the course of a building project.

House

A house is a building that functions as a home. They can range from simple dwellings such as rudimentary huts of nomadic tribes and the improvised shacks in shantytowns to complex, fixed structures of wood, brick, concrete or other materials containing plumbing, ventilation, and electrical systems. Houses use a range of different roofing systems to keep precipitation such as rain from getting into the dwelling space. Houses may have doors or locks to secure the dwelling space and protect its inhabitants and contents from burglars or other trespassers. Most conventional modern houses in Western cultures will contain one or more bedrooms and bathrooms, a kitchen or cooking area, and a living room. A house may have a separate dining room, or the eating area may be integrated into another room. Some large houses in North America have a recreation room. In traditional agriculture-oriented societies, domestic animals such as chickens or larger livestock (like cattle) may share part of the house with humans. The social unit that lives in a house is known as a household.

Most commonly, a household is a family unit of some kind, although households may also be other social groups, such as roommates or, in a rooming house, unconnected individuals. Some houses only have a dwelling space for one family or similar-sized group; larger houses called townhouses or row houses may contain numerous family dwellings in the same structure. A house may be accompanied by outbuildings, such as a garage for vehicles or a shed for gardening equipment and tools. A house may have a backyard or frontyard, which serve as additional areas where inhabitants can relax or eat.

Integer

An integer (from the Latin integer meaning "whole") is a number that can be written without a fractional component. For example, 21, 4, 0, and −2048 are integers, while 9.75, 5 1/2, and 2 are not.

The set of integers consists of zero (0), the positive natural numbers (1, 2, 3, …), also called whole numbers or counting numbers, and their additive inverses (the negative integers, i.e., −1, −2, −3, …). The set of integers is often denoted by a boldface Z ("Z") or blackboard bold (Unicode U+2124 ℤ) standing for the German word Zahlen ([ˈtsaːlən], "numbers").

Z is a subset of the set of all rational numbers Q, in turn a subset of the real numbers R. Like the natural numbers, Z is countably infinite.

The integers form the smallest group and the smallest ring containing the natural numbers. In algebraic number theory, the integers are sometimes qualified as rational integers to distinguish them from the more general algebraic integers. In fact, the (rational) integers are the algebraic integers that are also rational numbers.

John Deere

John Deere is the brand name of Deere & Company, an American corporation that manufactures agricultural, construction, and forestry machinery, diesel engines, drivetrains (axles, transmissions, gearboxes) used in heavy equipment, and lawn care equipment. In 2018, it was listed as 102nd in the Fortune 500 America's ranking and was ranked 394th in the global ranking. The company also provides financial services and other related activities.

Deere & Company is listed on the New York Stock Exchange under the symbol DE. The company's slogan is "Nothing Runs Like a Deere", and its logo is a leaping deer, with the words 'JOHN DEERE' under it. Various logos incorporating a leaping deer have been used by the company for over 155 years.

Levee

A levee (), dike, dyke, embankment, floodbank or stopbank is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels. It is usually earthen and often parallel to the course of a river in its floodplain or along low-lying coastlines.

List of nuclear reactors

This is a list of all the commercial nuclear reactors in the world, sorted by country, with operational status. The list only includes civilian nuclear power reactors used to generate electricity for a power grid. All commercial nuclear reactors use nuclear fission. As of April 2018, there are 449 operable power reactors in the world, with a combined electrical capacity of 394 GW. Additionally, there are 58 reactors under construction and 154 reactors planned, with a combined capacity of 63 GW and 157 GW, respectively.

Over 300 more reactors are proposed. For non-power reactors, see List of nuclear research reactors. Where not otherwise specified, all information is sourced from the Power Reactor Information System (PRIS) of the International Atomic Energy Agency (IAEA).

List of tallest buildings

This list of tallest buildings includes skyscrapers with continuously occupiable floors and a height of at least 350 m. Non-building structures, such as towers, are not included in this list (see list of tallest buildings and structures).

Historically, the world's tallest man-made structure was the Great Pyramids of Giza in Egypt, which held the position for over 3,800 years until the construction of the Lincoln Cathedral in England in 1311. Until the completion of the Washington Monument in 1884, the world's tallest buildings were churches and cathedrals, Christian places of worship, in Europe. The early skyscraper was pioneered in Chicago, forming the basis for which the United States would hold the position of the world's tallest building for much of the 20th century until 1998, when the Petronas Twin Towers were completed. Since then only two more buildings have held the title: Taipei 101 and Burj Khalifa.

Since the beginning of the 21st century, China, the Middle East as well as Southeast Asia have seen a boom in skyscraper construction.

One World Trade Center

One World Trade Center (also known as One WTC, 1 World Trade Center, 1 WTC, or Freedom Tower) is the main building of the rebuilt World Trade Center complex in Lower Manhattan, New York City. One WTC is the tallest building in the United States, the tallest building in the Western Hemisphere, and the sixth-tallest in the world. The supertall structure has the same name as the North Tower of the original World Trade Center, which was destroyed in the terrorist attacks of September 11, 2001. The new skyscraper stands on the northwest corner of the 16-acre (6.5 ha) World Trade Center site, on the site of the original 6 World Trade Center. The building is bounded by West Street to the west, Vesey Street to the north, Fulton Street to the south, and Washington Street to the east.

The building's architect is David Childs, whose firm Skidmore, Owings & Merrill (SOM) also designed the Burj Khalifa and the Willis Tower. The construction of below-ground utility relocations, footings, and foundations for the new building began on April 27, 2006. One World Trade Center became the tallest structure in New York City on April 30, 2012, when it surpassed the height of the Empire State Building. The tower's steel structure was topped out on August 30, 2012. On May 10, 2013, the final component of the skyscraper's spire was installed, making the building, including its spire, reach a total height of 1,776 feet (541 m). Its height in feet is a deliberate reference to the year when the United States Declaration of Independence was signed. The building opened on November 3, 2014; the One World Observatory opened on May 29, 2015.On March 26, 2009, the Port Authority of New York and New Jersey (PANYNJ) confirmed that the building would be officially known by its legal name of "One World Trade Center", rather than its colloquial name of "Freedom Tower". The building is 104 standard floors high, but the tower has only 94 actual stories.

The new World Trade Center complex will eventually include five high-rise office buildings built along Greenwich Street, as well as the National September 11 Memorial & Museum, located just south of One World Trade Center where the original Twin Towers stood. The construction of the new building is part of an effort to memorialize and rebuild following the destruction of the original World Trade Center complex.

Road

A road is a thoroughfare, route, or way on land between two places that has been paved or otherwise improved to allow travel by foot or some form of conveyance, including a motor vehicle, cart, bicycle, or horse.

Roads consist of one or two roadways (British English: carriageways), each with one or more lanes and any associated sidewalks (British English: pavement) and road verges. There is sometimes a bike path. Other names for roads include parkways, avenues, freeways, tollways, interstates, highways, or primary, secondary, and tertiary local roads.

Sagrada Família

The Temple Expiatori de la Sagrada Família (Catalan: [ˈtemplə əkspjəˈtoɾi ðə la səˈɣɾaðə fəˈmiljə]; Spanish: Templo Expiatorio de la Sagrada Familia; "Expiatory Church of the Holy Family") is a large unfinished Roman Catholic church in Barcelona. Designed by Catalan architect Antoni Gaudí (1852–1926), his work on the building is part of a UNESCO World Heritage Site. In November 2010, Pope Benedict XVI consecrated the church and proclaimed it a minor basilica.In 1882, construction of Sagrada Família began under architect Francisco de Paula del Villar. In 1883, when Villar resigned, Gaudí took over as chief architect, transforming the project with his architectural and engineering style, combining Gothic and curvilinear Art Nouveau forms. Gaudí devoted the remainder of his life to the project, and he is buried in the crypt. At the time of his death in 1926, less than a quarter of the project was complete.Relying solely on private donations, Sagrada Familia's construction progressed slowly and was interrupted by the Spanish Civil War. In July 1936, revolutionaries set fire to the crypt and broke their way into the workshop, partially destroying Gaudí's original plans, drawings and plaster models, which led to 16 years work to piece together the fragments of the master model. Construction resumed to intermittent progress in the 1950s. Advancements in technologies such as computer aided design and computerised numerical control (CNC) have since enabled faster progress and construction past the midpoint in 2010. However, some of the project's greatest challenges remain, including the construction of ten more spires, each symbolising an important Biblical figure in the New Testament. It is anticipated that the building can be completed by 2026, the centenary of Gaudí's death.

The basilica has a long history of splitting opinion among the residents of Barcelona: over the initial possibility it might compete with Barcelona's cathedral, over Gaudí's design itself, over the possibility that work after Gaudí's death disregarded his design, and the 2007 proposal to build a tunnel of Spain's high-speed rail link to France which could disturb its stability. Describing Sagrada Família, art critic Rainer Zerbst said "it is probably impossible to find a church building anything like it in the entire history of art", and Paul Goldberger describes it as "the most extraordinary personal interpretation of Gothic architecture since the Middle Ages".

Seabee

United States Naval Construction Battalions, better known as the Seabees, form the Naval Construction Force (NCF) of the United States Navy. Their nickname is a heterograph of the first initials "C.B." from the words Construction Battalion. Depending upon how the word is used "Seabee" can refer to one of three things: all the enlisted personnel in the USN's occupational field-7 (OF-7), all officers and enlisted assigned to the Naval Construction Force, or the U.S. Navy's Construction Battalions (CBs). Seabees also serve outside the NCF. During WWII they served in both the Naval Combat Demolition Units and the UDTs as well as the United States Marine Corps. Today they can be found in many special needs assignments: Naval Support Unit: Department of State, at Camp David, manning many Naval Facilities Public Works or the Naval Facilities Mobile Support Equipment Group(MUSE) or any overseas Naval Station Public Works, under both Commanders of the Naval Surface Forces Alantic/Pacific fleets, in various USN diving commands and the Combat Service Support Task Unit (Naval Special Warfare).

Naval Construction Battalions were conceived of as a replacement for civilian construction companies working for the US Navy after the United States was drawn into World War II with the Japanese attack on Pearl Harbor on 7 December 1941. At that time the U.S. had roughly 70,000 civilians working on military installations overseas. International law made it illegal for them to resist enemy attack, as to do so would classify them as guerrillas, for which they could be summarily executed, which is exactly what happened when the Japanese invaded Wake Island.Admiral Moreell's concept model of CBs was that of a USMC–trained battalion of construction tradesmen (a military equivalent of those civilian companies) that would be capable of any type of construction, anywhere needed, under any conditions or circumstance. It was quickly realized that this model could be utilized in every theater of operations, as it was seen to be flexible and adaptable.The use of USMC organization allowed for smooth co-ordination, integration or interface of both the NCF and Marine Corps elements. In addition, Seabee Battalions could be deployed individually or in multiples as the project scope and scale dictated. What distinguishes Seabees from Combat Engineers are the skill sets. Combat Engineering is but a sub-set in the Seabee toolbox. They have a storied legacy of creative field ingenuity, stretching from Normandy and Okinawa to Iraq and Afghanistan. Admiral Ernest King wrote to the Seabees on their second anniversary, "Your ingenuity and fortitude have become a legend in the naval service." Seabees believe that anything they are tasked with they "Can Do" (the CB motto). They were unique at conception and remain so today. In the October 1944 issue of Flying magazine the Seabees are described as "a phenomenon of World War II". In 2017, the Seabees celebrated their 75 years of service without having changed from Admiral Ben Moreell's conceptual model.

Skyscraper

A skyscraper is a continuously habitable high-rise building that has over 40 floors and is taller than approximately 150 m (492 ft). Historically, the term first referred to buildings with 10 to 20 floors in the 1880s. The definition shifted with advancing construction technology during the 20th century. Skyscrapers may host commercial offices or residential space, or both. For buildings above a height of 300 m (984 ft), the term supertall skyscrapers can be used, while skyscrapers reaching beyond 600 m (1,969 ft) are classified as megatall Skyscrapers.One common feature of skyscrapers is having a steel framework 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 of those made of reinforced concrete.

Modern skyscrapers' 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 are sometimes also structurally required.

Social constructionism

Social constructionism is a theory of knowledge in sociology and communication theory that examines the development of jointly constructed understandings of the world that form the basis for shared assumptions about reality. The theory centers on the notion that meanings are developed in coordination with others rather than separately within each individual.Social constructionism questions what is defined by humans and society to be reality. Therefore, social constructs can be different based on the society and the events surrounding the time period in which they exist. An example of a social construct is money or the concept of currency, as people in society have agreed to give it importance/value. Another example of a social construction is the concept of self/self-identity. Charles Cooley stated based on his Looking-Glass-Self theory: "I am not who you think I am; I am not who I think I am; I am who I think you think I am." This demonstrates how people in society construct ideas or concepts that may not exist without the existence of people or language to validate those concepts.There are weak and strong social constructs. Weak social constructs rely on brute facts (which are fundamental facts that are difficult to explain or understand, such as quarks) or institutional facts (which are formed from social conventions). Strong social constructs rely on the human perspective and knowledge that does not just exist, but is rather constructed by society.

Sydney Opera House

The Sydney Opera House is a multi-venue performing arts centre at Sydney Harbour in Sydney, New South Wales, Australia. It is one of the 20th century's most famous and distinctive buildings.Designed by Danish architect Jørn Utzon, the building was formally opened on 20 October 1973 after a gestation beginning with Utzon's 1957 selection as winner of an international design competition. The Government of New South Wales, led by the premier, Joseph Cahill, authorised work to begin in 1958 with Utzon directing construction. The government's decision to build Utzon's design is often overshadowed by circumstances that followed, including cost and scheduling overruns as well as the architect's ultimate resignation.The building and its surrounds occupy the whole of Bennelong Point on Sydney Harbour, between Sydney Cove and Farm Cove, adjacent to the Sydney central business district and the Royal Botanic Gardens, and close by the Sydney Harbour Bridge.

The building comprises multiple performance venues, which together host well over 1,500 performances annually, attended by more than 1.2 million people. Performances are presented by numerous performing artists, including three resident companies: Opera Australia, the Sydney Theatre Company and the Sydney Symphony Orchestra. As one of the most popular visitor attractions in Australia, the site is visited by more than eight million people annually, and approximately 350,000 visitors take a guided tour of the building each year. The building is managed by the Sydney Opera House Trust, an agency of the New South Wales State Government.

On 28 June 2007, the Sydney Opera House became a UNESCO World Heritage Site, having been listed on the (now defunct) Register of the National Estate since 1980, the National Trust of Australia register since 1983, the City of Sydney Heritage Inventory since 2000, the New South Wales State Heritage Register since 2003, and the Australian National Heritage List since 2005. Furthermore, the Opera House was a finalist in the New7Wonders of the World campaign list.

Taj Mahal

The Taj Mahal (; Hindi: ताज महल [taːdʒ ˈmɛːɦ(ə)l], meaning "Crown of the Palaces") is an ivory-white marble mausoleum on the south bank of the Yamuna river in the Indian city of Agra. It was commissioned in 1632 by the Mughal emperor, Shah Jahan (reigned from 1628 to 1658), to house the tomb of his favourite wife, Mumtaz Mahal. It also houses the tomb of Shah Jahan, the builder. The tomb is the centerpiece of a 17-hectare (42-acre) complex, which includes a mosque and a guest house, and is set in formal gardens bounded on three sides by a crenellated wall.

Construction of the mausoleum was essentially completed in 1643 but work continued on other phases of the project for another 10 years. The Taj Mahal complex is believed to have been completed in its entirety in 1653 at a cost estimated at the time to be around 32 million rupees, which in 2015 would be approximately 52.8 billion rupees (U.S. $827 million). The construction project employed some 20,000 artisans under the guidance of a board of architects led by the court architect to the emperor, Ustad Ahmad Lahauri.

The Taj Mahal was designated as a UNESCO World Heritage Site in 1983 for being "the jewel of Muslim art in India and one of the universally admired masterpieces of the world's heritage". It is regarded by many as the best example of Mughal architecture and a symbol of India's rich history. The Taj Mahal attracts 7–8 million visitors a year and in 2007, it was declared a winner of the New7Wonders of the World (2000–2007) initiative.

Timber framing

Timber framing and "post-and-beam" construction are traditional methods of building with heavy timbers, creating structures using squared-off and carefully fitted and joined timbers with joints secured by large wooden pegs. It is commonplace in wooden buildings from the 19th century and earlier. If the structural frame of load-bearing timber is left exposed on the exterior of the building it may be referred to as half-timbered, and in many cases the infill between timbers will be used for decorative effect. The country most known for this kind of architecture is Germany. Timber framed houses are spread all over the country except in the southeast.

The method comes from working directly from logs and trees rather than pre-cut dimensional lumber. Hewing this with broadaxes, adzes, and draw knives and using hand-powered braces and augers (brace and bit) and other woodworking tools, artisans or framers could gradually assemble a building.

Since this building method has been used for thousands of years in many parts of the world, many styles of historic framing have developed. These styles are often categorized by the type of foundation, walls, how and where the beams intersect, the use of curved timbers, and the roof framing details.

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