Construction is a general term meaning the and to form , , or ,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and comes from ''constructio'' (from ''com-'' "together" and ''struere'' "to pile up") and ''construction''. To construct is the : the act of building, and the is construction: how something is built, the nature of its structure.
In its most widely used context, construction covers the processes involved in delivering s, , industrial facilities and associated activities through to the end of their life. It typically starts with , , and , and continues until the asset is built and ready for use; construction also covers repairs and maintenance work, any works to expand, extend and improve the asset, and its eventual , dismantling or ing.
The construction industry contributes significantly to many countries’ gross domestic products (GDP). Global expenditure on construction activities was about $4 trillion in 2012. Today, expenditure on the construction industry exceeds $11 trillion a year, equivalent to about 13 percent of global GDP. This spending was forecast to rise to around $14.8 trillion in 2030.
Although the construction industry promotes economic development and brings many non-monetary benefits to many countries, it is one of the most hazardous industries. For example, about 20% (1,061) of US industry fatalities in 2019 happened in construction.
History
The first and shelters were constructed by hand or with simple tools. As grew during the , a class of professional , like s and , appeared. Occasionally, were used for construction work. In the , the artisan craftsmen were organized into s. In the 19th century, steam-powered machinery appeared, and, later, diesel- and electric-powered vehicles such as , s and s. has been increasingly popular in the 21st century. Some estimates suggest that 40% of construction projects are now fast-track construction.Construction industry sectors
Broadly, there are three sectors of construction: buildings, infrastructure and industrial:
* Building construction is usually further divided into residential and non-residential.
* Infrastructure, also called , includes large public works, dams, bridges, highways, railways, water or wastewater and utility distribution.
* Industrial construction includes (mainly of energy installations), mining and quarrying, , chemical processing, , mills and .
The industry can also be classified into sectors or markets. For example, ' (''ENR''), a US-based construction trade magazine, has compiled and reported data about the size of design and construction contractors. In 2014, it split the data into nine market segments: transportation, , buildings, power, industrial, water, manufacturing, sewer/waste, , hazardous waste, and a tenth category for other projects. ''ENR'' used data on transportation, sewer, hazardous waste and water to rank firms as heavy contractors.
The and the newer classify companies that perform or engage in construction into three subsectors: building construction, heavy and civil engineering construction, and specialty trade contractors. There are also categories for professional services firms (e.g., , , , ).
Building construction
Building construction is the process of adding structures to areas of land, also known as sites. Typically, a project is instigated by or with the owner of the property (who may be an individual or an organisation); occasionally, land may be from the owner for public use.Residential construction
Residential construction may be undertaken by individual land-owners (), by specialist , by s, by s, or by providers of (e.g.: local authorities, s). Where local or policies allow, s may comprise both residential and non-residential construction (e.g.: retail, leisure, offices, public buildings, etc.). Residential construction practices, technologies, and resources must conform to local building authority regulations and . Materials readily available in the area generally dictate the construction materials used (e.g.: versus stone versus ). Costs of construction on a per square meter (or per square foot) basis for s can vary dramatically based on site conditions, access routes, local regulations, (custom-designed homes are often more expensive to build) and the availability of skilled tradespeople.Non-residential construction
Depending upon the , non-residential building construction can be procured by a wide range of private and public organisations, including local authorities, educational and religious bodies, transport undertakings, retailers, hoteliers, property developers, financial institutions and other private companies. Most construction in these sectors is undertaken by general contractors.
Infrastructure construction
Civil engineering covers the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, tunnels, airports, water and sewerage systems, pipelines, and railways. Some general contractors have expertise in civil engineering; civil engineering contractors are firms dedicated to work in this sector, and may specialise in particular types of infrastructure.
Industrial construction
includes offshore construction (mainly of energy installations: , ), and ing, , , and other processing plants, s, s, s and .
Construction processes
Some construction projects are small renovations or repair jobs, where the owner may act as designer, paymaster and laborer for the entire project. However, more complex or ambitious projects usually require additional multi-disciplinary expertise and manpower, so the owner may commission one or more specialist businesses to undertake detailed planning, design, construction and handover of the work. Often the owner will appoint one business to oversee the project (this may be a , a , a , or other advisors); such specialists are normally appointed for their expertise in project delivery, and will help the owner define the project , agree on a and , liaise with relevant public authorities, and procure the services of other specialists (the , comprising s). are agreed for the delivery of services by all businesses, alongside other detailed plans aimed at ensuring legal, timely, on-budget and safe delivery of the specified works. 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 be adequate to build the design provided, and must pay amounts that are legally owed. Legal structures integrate design with other activities, and enforce financial and other construction processes. These processes also affect procurement strategies. Clients may, for example, appoint a business to design the project after which a competitive process is undertaken to appoint a lead contractor to construct the asset (); they may appoint a business to lead both design and construction (); or they may directly appoint a designer, contractor and specialist subcontractors (). Some forms of procurement emphasize collaborative relationships (, alliancing) between the client, the contractor, and other stakeholders within a construction project, seeking to ameliorate often highly competitive and adversarial industry practices.Planning
When applicable, a proposed construction project must comply with local policies including and requirements. A project will normally be assessed (by the 'authority having jurisdiction, AHJ, typically the where the project will be located) for its potential impacts on neighbouring properties, and upon existing infrastructure (transportation, social infrastructure, and utilities including water supply, sewerage, electricity, telecommunications, etc.). Data may be gathered through , s and s. Construction normally cannot start until has been granted, and may require preparatory work to ensure relevant infrastructure has been upgraded before building work can commence. Preparatory works will also include surveys of existing utility lines to avoid damage-causing outages and other hazardous situations.
Some legal requirements come from ' considerations, or the desire to prevent indisputably bad phenomena, e.g. explosions or bridge collapses. Other legal requirements come from ' 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).
During the construction of a building, a municipal building inspector usually inspects the ongoing work periodically to ensure that construction adheres to the approved plans and the local building code. Once construction is complete, any later changes made to a building or other asset that affect safety, including its use, expansion, structural integrity, and , usually require municipality approval.
Finance
Depending on the type of project, ers, s, and may participate in creating an overall plan for the financial management of a 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. Professionals including cost engineers, and s apply expertise to relate the work and materials involved to a proper valuation. Financial planning ensures adequate safeguards and contingency plans are in place before the project is started, and ensures that the plan is properly executed over the life of the project. Construction projects can suffer from preventable financial problems. Underbids happen when builders ask for too little money to complete the project. problems exist when the present amount of funding cannot cover the current costs for labour and materials; such problems may arise even when the overall budget is adequate, presenting a temporary issue. 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. is also an occasional construction issue. Large projects can involve highly complex financial plans and often start with a conceptual performed by a . 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 carry forward. s (PPPs) or s (PFIs) may also be used to help deliver major projects. According to in 2019, the "vast majority of large construction projects go over budget and take 20% longer than expected".Legal
A construction project is a complex net of s 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, and provides structures to manage issues. For example, construction delays can be costly, so construction contracts set out clear expectations and clear paths to manage delays. Poorly drafted contracts can lead to confusion and costly disputes.
At the start of a project, legal advisors seek to identify ambiguities and other potential sources of trouble in the contract structures, and to present options for preventing problems. During projects, 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.
Procurement
Traditional or Design-bid-build
Design-bid-build is the most common and well-established method of construction procurement. In this arrangement, the , or builder acts for the client as the project coordinator. They design the works, prepare specifications and design deliverables (models, drawings, etc.), administer the contract, the works, and manage the works from inception to completion. In parallel, there are direct contractual links between the client and the main contractor, who, in turn, has direct contractual relationships with subcontractors. The arrangement continues until the project is ready for handover.Design-build
Design-build became more common from the late 20th century, and involves the client contracting a single entity to provide design and construction. In some cases, the design-build package can also include finding the site, arranging funding and applying for all necessary statutory consents. Typically, the client invites several D&B contractors to submit proposals to meet the project brief and then selects a preferred supplier. Often this will be a involving a design firm and a contractor (sometimes more than one of each). In the United States, usually use design-build contracts as a way of progressing projects where states lack the skills or resources, particularly for very large projects.Construction management
In a construction management arrangement, the client enters into separate contracts with the designer (architect or engineer), a , and individual . 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. This approach is often used to speed up procurement processes, to allow the client greater flexibility in design variation throughout the contract, to enable the appointment of individual work contractors, to separate contractual responsibility on each individual throughout the contract, and to provide greater client control.Design
In the industrialized world, construction usually involves the translation of designs into reality. Most commonly (ie: in a design-bid-build project), the design team is employed by (i.e. in contract with) the property owner. Depending upon the type of project, a design team may include s, s, , , s, , planning s, architectural consultants, and archaeological consultants. A 'lead designer' will normally be identified to help coordinate different disciplinary inputs to the overall design. This may be aided by integration of previously separate disciplines (often undertaken by separate firms) into multi-disciplinary firms with experts from all related fields, or by firms establishing relationships to support design-build processes. The increasing complexity of construction projects creates the need for design professionals trained in all phases of a project's life-cycle and develop an appreciation of the asset as an advanced technological system requiring close integration of many sub-systems and their individual components, including sustainability. For buildings, is an emerging discipline that attempts to meet this new challenge. Traditionally, design has involved the production of es, and s, and . Until the late 20th century, drawings were largely hand-; adoption of (CAD) technologies then improved design productivity, while the 21st-century introduction of (BIM) processes has involved the use of computer-generated models that can be used in their own right or to generate drawings and other visualisations as well as capturing non-geometric data about building components and systems. On some projects, work on-site will not start until design work is largely complete; on others, some design work may be undertaken concurrently with the early stages of on-site activity (for example, work on a building's foundations may commence while designers are still working on the detailed designs of the building's internal spaces). Some projects may include elements that are designed for (see also and ) and are then delivered to the site ready for erection, installation or assembly.On-site construction
Once contractors and other relevant professionals have been appointed and designs are sufficiently advanced, work may commence on the project site. Typically, a construction site will include a secure perimeter to restrict unauthorised access, site access control points, office and welfare accommodation for personnel from the main contractor and other firms involved in the project team, and storage areas for materials, machinery and equipment. According to the ''McGraw-Hill Dictionary of Architecture and Construction's'' definition, construction may be said to have ''started'' when the first feature of the permanent structure has been put in place, such as pile driving, or the pouring of slabs or footings.
Commissioning and handover
Commissioning is the process of verifying that all subsystems of a new building (or other assets) work as intended to achieve the owner's project requirements and as designed by the project's architects and engineers.Maintenance, repair and improvement
Maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, ry, building infrastructure, and supporting utilities in industrial, business, governmental, and residential installations.Demolition
Demolition is the discipline of safely and efficiently tearing down s and other artificial s. Demolition contrasts with , which involves taking a building apart while carefully preserving valuable elements for reuse purposes ( - see also ).Industry scale and characteristics
Economic activity
The output of the global construction industry was worth an estimated $10.8 trillion in 2017, and in 2018 was forecast to rise to $12.9 trillion by 2022, and to around $14.8 trillion in 2030. As a sector, construction accounts for more than 10% of global GDP (in , construction comprises 6-9% of GDP), and employs around 7% of the total employed workforce around the globe (accounting for over 273 million full- and part-time jobs in 2014). Since 2010, China has been the world's largest single construction market. The United States is the second largest construction market with a 2018 output of $1.581 trillion.
In the United States in February 2020, around $1.4 trillion worth of construction work was in progress, according to the , of which just over $1.0 trillion was for the (split roughly 55:45% between residential and nonresidential); the remainder was , predominantly for state and local government.
Construction is a major source of employment in most countries; high reliance on small businesses, and under-representation of women are common traits. For example:
* In the US, construction employed around 11.4m people in 2020, with a further 1.8m employed in architectural, engineering, and related professional services - equivalent to just over 8% of the total US workforce. The construction workers were employed in over 843,000 organisations, of which 838,000 were privately held businesses. In March 2016, 60.4% of construction workers were employed by businesses with fewer than 50 staff. Women are substantially underrepresented (relative to their share of total employment), comprising 10.3% of the US construction workforce, and 25.9% of professional services workers, in 2019.
* In the United Kingdom, construction contributed £117 billion (6%) to UK GDP in 2018, and in 2019 employed 2.4m workers (6.6% of all jobs). These worked either for 343,000 'registered' construction businesses, or for 'unregistered' businesses, typically self-employed contractors; just over one million small/medium-sized businesses, mainly self-employed individuals, worked in the sector in 2019, comprising about 18% of all UK businesses. Women comprised 12.5% of the UK construction workforce.
* In , the construction sector experienced growth during the latter part of 2000s. Based on National Statistical Service, Armenia's construction sector generated approximately 20% of Armenia's GDP during the first and second quarters of 2007. In 2009, according to the World Bank, 30% of Armenia's economy was from construction sector."Armenian Growth Still In Double Digits"Armenia Liberty (), September 20, 2007. According to research, growth per worker in construction has lagged behind many other industries across different countries including in the and in European countries. In the United States, construction productivity per worker has declined by half since the 1960s.
Construction GVA by country
Careers
Large-scale construction requires across multiple disciplines. A normally manages the budget on the job, and a , , or supervises it. Those involved with the design and execution must consider zoning requirements and legal issues, of the project, , ing and , , availability and transportation of s, logistics, and inconvenience to the public, including those caused by s.
There are many routes to the different s within the construction industry. There are three main tiers based on educational background and training, which vary by country:
Unskilled and semi-skilled workers
Unskilled and semi-skilled workers provide general site labor, often have few or no construction qualifications, and may receive basic site training.Skilled tradespeople
Skilled have typically served s (sometimes in s) or received technical training; this group also includes on-site managers who possess extensive knowledge and experience in their or . Skilled manual occupations include s, s, s, s, s and , as well as those involved in project management. In the these require qualifications, often in al subject areas, undertaken either directly after completing or through "on the job" apprenticeships.Professional, technical or managerial personnel
Professional, technical and managerial personnel often have qualifications, usually , and are trained to design and manage construction processes. These roles require more training as they demand greater technical knowledge, and involve more legal responsibility. Example roles (and qualification routes) include: * – Will usually have studied to degree level, and then undertaken further study and gained professional experience. In many countries, the title of "architect" is protected by law, strictly limiting its use to qualified people. * – Typically holds a degree in a related subject and may only be eligible for membership of a professional institution (such as the UK's ) following completion of additional training and experience. In some jurisdictions, a new university graduate must hold a to become chartered, and persons with s may become s. * – May also be referred to as an "M&E" or "MEP engineer" and typically holds a degree in mechanical or electrical engineering. * – Typically holds a 4-year or greater qualification, but are often also qualified in another field such as architecture, civil engineering or quantity surveying. * – Typically holds a bachelor's or master's degree in structural engineering. * – Typically holds a bachelor's degree in quantity surveying. UK chartered status is gained from the .Safety
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 . In the US in 2019, 1,061, or about 20%, of worker fatalities in private industry occurred in construction. In 2017, more than a third of US construction fatalities (366 out of 971 total fatalities) were the result of falls. Proper safety equipment such as harnesses, hard hats and guardrails and procedures such as securing ladders and inspecting can curtail the risk of occupational injuries in the construction industry. Other major causes of fatalities in the construction industry include electrocution, transportation accidents, and trench cave-ins.
Other safety risks for workers in construction include due to high noise exposure, , chemical exposure, and high levels of stress. 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 (NIOSH) as a priority industry sector in the (NORA) to identify and provide intervention strategies regarding occupational health and safety issues.
Sustainability
Sustainability is an aspect of “green building", defined by the United States (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."See also
* * * * * * *References and notes
{{Authority control