Building construction is the process of preparing for and forming buildings and building systems. Construction starts with planning, design, and financing and continues until the structure is ready for occupancy.
Far from being a single activity, large scale construction is a feat of human multitasking. Normally, the job is managed by a project manager, and supervised by a construction manager, design engineer, construction engineer or project architect. For the successful execution of a project, effective planning is essential. Those involved with the design and execution of the infrastructure in question must consider the environmental impact of the job, the successful scheduling, budgeting, construction site safety, availability and transportation of building materials, logistics, inconvenience to the public caused by construction delays and bidding, etc.
Types of construction projects
In general, there are nine types of construction:- Residential building construction
- light commercial construction
- Multi-family construction
- Health-Care construction
- Environmental construction
- Industrial construction
- Commercial building construction
- Institutional construction
- Heavy civil construction
Building construction
Building construction is the process of adding structure to real property or construction of buildings. The vast 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. However, all building construction projects include some elements in common – design, financial, estimating and legal considerations. Many projects of varying sizes 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.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 tradespeople. As residential construction (as well as all other types of construction) can generate a lot of waste, careful planning again is needed here.
The most popular method of residential construction in the United States is wood framed construction. As efficiency codes have come into effect in recent years, new construction techniques are used. This
new techniques of building construction are being researched, made possible by advances in 3D printing technology. In a form of additive building construction, similar to the additive manufacturing techniques for manufactured parts, building printing is making it possible to flexibly construct small commercial buildings and private habitations in around 20 hours, with built-in plumbing and electrical facilities, in one continuous build, using large 3D printers. Working versions of 3D-printing building technology are already printing 2 metres (6 ft 7 in) of building material per hour as of January 2013, with the next-generation printers capable of 3.5 metres (11 ft) per hour, sufficient to complete a building in a week.
In the current trend of sustainable construction the recent movements of New Urbanism and New Classical Architecture promote a sustainable approach towards construction, that appreciates and develops smart growth, architectural tradition and classical design. This in contrast to modernist and short-lived globally uniform architecture, as well as opposing solitary housing estates and suburban sprawl.[10] Both trends started in the 1980s.
Construction processes
Design team
Shasta Dam under construction in June 1942
In the modern 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 surveyors,
civil
engineers, cost engineers (or quantity
surveyors), 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 will typically award a contract to the most cost
efficient bidder.The 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.
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
Construction projects can suffer from preventable financial problems. Underbids 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. 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 was able to identify change orders or changes in the project resulting in large increases in cost, which are not subject to competition by other firms as they have already been eliminated from consideration after the initial bid.
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
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.
The project must adhere to zoning and building
code requirements. Constructing a project that fails to adhere to
codes will not benefit the owner. Some legal requirements come from malum
in se considerations, or the desire to prevent things that are
indisputably bad – bridge collapses or explosions. Other legal
requirements come from malum prohibitum
considerations, or things that are a matter of custom or expectation, such as
isolating businesses to a business district and residences to a residential
district. An attorney may seek changes or exemptions in the law governing the
land where the building will be built, either by arguing that a rule is
inapplicable (the bridge design will not collapse), or that the custom is no
longer needed (acceptance of live-work spaces has grown in the community).A construction project is a complex net of contracts and other legal obligations, each of which must be carefully considered. 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
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 and build
- Management contracting
Traditional
Main article: Design–bid–build
This is the most common method of construction procurement and 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 will
have a direct contractual relationship with the main contractor.Design and build
This approach has become more common in recent years, and involves the client contracting a single entity to both provide a design and to build that design. In some cases, the Design and Build (D & B) 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 he or she likes best and hires the appropriate contractor. Often, it is not just one contractor, but a consortium of several contractors working together. Once a contractor (or a consortium/consortia) has 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 (DOTs) usually use design build contracts as a way of getting projects done when states don't have the resources. In DOTs, design build contracts are usually used for very large projects.
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.
Authority having jurisdiction
In construction, the authority having jurisdiction (AHJ) is the governmental agency or sub-agency which regulates the construction process. In most cases, this is the municipality in which the building is located. However, construction performed for supra-municipal authorities are usually regulated directly by the owning authority, which becomes the AHJ.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.
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 has around $850 billion in annual revenue according to statistics tracked by the Census Bureau, with an $857 billion annual rate in March 2013, of which $600 billion is private (split evenly between residential and nonresidential) and the remainder is government. As of 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. As a whole, the industry employed an estimated 5.8 million as of April 2013, with a 13.2% unemployment rate.Careers
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.
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:
- Quantity surveyor – Typically holds a
master's degree in quantity surveying.
- Architect – Typically holds 1, undergraduate 3 year degree in architecture + 1, post-graduate 2 year degree (DipArch or BArch) in architecture plus 24 months experience within the industry. To use the title "architect"
- Civil engineer – Typically holds a degree in a related subject. The Chartered Engineer qualification is controlled by the Engineering Council . A new university graduate must hold a master's degree to become chartered; persons with bachelor's degrees may become an Incorporated Engineer.
- Building services engineer –
Often referred to as an "M&E Engineer" typically holds a
degree in mechanical or electrical engineering. Chartered Engineer status
is governed by the Engineering Council.
- Project manager – Typically holds a 4-year or greater higher education qualification, but are often also qualified in another field such as quantity surveying or civil engineering.
- Structural engineer – Typically holds a bachelor's or master's degree in structural engineering. A P.ENG is required from the Professional Engineers Ontario (Canada). New university graduates must hold a master's degree to gain chartered status from the Engineering Council.
- Civil Estimators are professionals who typically have a background in civil engineering, construction project management, or construction supervision.
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 European Union. In 2009, the fatal occupational injury rate among construction workers in the United States was nearly three times that for all workers. Falls are one of the most common causes of fatal and non-fatal injuries among construction workers. Proper safety equipment such as harnesses and guardrails and procedures such as securing ladders and inspecting scaffolding 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.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, these 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.
Construction phases
- Vision/fantasy/idea - a concept never intended to be built, may be an aesthetic or structural design exercise
- Proposed - a building concept that is under review by a government
- Approved - a building concept that will be constructed in the near future
- Deferred - a building concept that may be constructed in the far future
- Cancelled - a building concept that usually has lost funding or support, in some cases construction already started
- Under-construction - a fully designed building currently being built
- Topped-out - a fully designed building that has reached its highest point
- Complete/built - a fully designed building that has been fully built, excluding future expansions
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