In large construction projects such as skyscrapers, cranes are essential.

In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of multitasking. Normally the job is managed by the project manager and supervised by the 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, site safety, availability of materials, logistics, inconvenience to the public caused by construction delays, preparing tender documents, etc.

Types of construction projects

In general, there are three types of construction:

1. Building construction
2. Heavy/civil construction
3. Industrial construction

Each type of construction project requires a unique team to plan, design, construct, and maintain the project.

Building construction

Building construction for several apartment blocks. The blue material is insulation cladding, which will be covered later.

A large unfinished building

Building construction is the process of adding structure to real property. The vast majority of building construction projects 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, and legal considerations. Many projects of varying sizes reach undesirable end results, such as structural collapse, cost overruns, and/or litigation reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome.

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

Trump International Hotel and Tower (Chicago)

May, 23, 2006

September 14, 2007

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 metre (or per square foot) basis for houses can vary dramatically based on site conditions, local regulations, economies of scale (custom designed homes are always more expensive to build) and the availability of skilled tradespeople. As residential (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 technologies and methods have emerged. University Construction Management departments are on the cutting edge of the newest methods of construction intended to improve efficiency, performance and reduce construction waste.

Construction of the Havelock City Project in Sri Lanka.

Construction of Phase-1 of the Havelock City Project in Sri Lanka.

Industrial construction

Industrial construction, though a relatively small part of the entire construction industry, is a very important component. Owners of these projects are usually large, for-profit, industrial corporations. These corporations can be found in such industries as medicine, petroleum, chemical, power generation, manufacturing, etc. Processes in these industries require highly specialized expertise in planning, design, and construction. As in building and heavy/highway construction, this type of construction requires a team of individuals to ensure a successful project.

Construction processes

Design team

Shasta Dam under construction

In the modern industrialized world, construction usually involves the translation of paper or computer based 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 the client architects, interior designers, surveyors, civil engineers, cost engineers (or quantity surveyors), mechanical engineers, electrical engineers, structural engineers, and fire protection engineers. 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 lowest responsible bidder.

Apartment is under counstruction in Daegu, South Korea.

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.

Construction of a pre-fabricated house

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

Many construction projects 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, is 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 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 firm as they have already been eliminated from consideration after the initial bid.^[1]

Large projects can involve highly complex financial plans. 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 considerations

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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 won’t 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.

Interaction of expertise

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 enforces 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:

1. Traditional (Design-bid-build)
2. Design and Build
3. Management Contracting

Traditional

This 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 includes an entire completed package, including fixtures, fittings and equipment where necessary, to produce a completed fully functional building. 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 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, director of engineering for the National Asphalt Pavement Association (NAPA), 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. ^[2]

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 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, 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

The examples and perspective in this article deal primarily with North America and do not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page.

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.

During the planning of a building, the zoning and planning boards of the AHJ will review the overall compliance of the proposed building with the municipal General Plan and zoning regulations. Once the proposed building has been approved, detailed civil, architectural, and structural plans must be submitted to the municipal building department (and sometimes the public works department) to determine compliance with the building code and sometimes for fit with existing infrastructure. Often, the municipal fire department will review the plans for compliance with fire-safety ordinances and regulations.

Construction on a building in Kansas City

Before the foundation can be dug, contractors are typically required to notify utility companies, either directly or through a company such as Dig Safe to ensure that underground utility lines can be marked. 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.

Construction careers

The examples and perspective in this section deal primarily with the United Kingdom and do not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page.

Ironworkers erecting the steel frame of a new building, at the Massachusetts General Hospital, USA

There are many routes to the different careers within the construction industry which vary by country. However, there are three main tiers of careers based on educational background which are common internationally:

• Unskilled and Semi-Skilled – General site labour with little or no construction qualifications.
• Skilled – On-site managers whom 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 in the UK 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. In the UK, 8500 construction-related apprenticeships were commenced in 2007.^[3]

Technical and specialised 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:^[4]

• Architect – Typically holds at least a 4-year degree in architecture. To use the title “architect” the individual must hold chartered status with the Royal Institute of British Architects and be on the Architects Registration Board.
• Civil Engineer – Typically holds a degree in a related subject. The Chartered Engineer qualification is controlled by the Institution of Civil Engineers. A new university graduate must hold a masters degree to become chartered, persons with bachelors 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 Chartered Institution of Building Services Engineers.
• Project Manager – Typically holds a 2-year or greater higher education qualification, but are often also qualified in another field such as quantity surveying or civil engineering.
• Quantity Surveyor – Typically holds a masters degree in quantity surveying. Chartered status is gained from the Royal Institute of Chartered Surveyors.
• Structural Engineer – Typically holds a bachelors or masters degree in structural engineering, new university graduates must hold a masters degree to gain chartered status from the Institution of Structural Engineers.

History

The first buildings were huts and shelters, 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.

The scenario was developed with the “World Editor” of Warcraft III: Reign of Chaos, and was updated upon the release of the expansion, The Frozen Throne. There have been many variations of the original concept; the most popular is DotA Allstars, which has been maintained by several authors during development. The current developer is known by his pseudonym as “IceFrog”.

Since its release, Allstars has become a feature at several worldwide tournaments, including Blizzard Entertainment‘s BlizzCon and the Asian World Cyber Games, as well as the Cyberathlete Amateur and CyberEvolution leagues; Gamasutra declared that DotA was perhaps the most popular “free, non-supported game mod in the world”.^[3]

Gameplay

A game of DotA Allstars in progress

Defense of the Ancients pits two teams of players against each other: the Sentinel and the Scourge. Players on the Sentinel team are based at the southwest corner of the map, and those on the Scourge team are based at the northeast corner. Each base is defended by towers and waves of units which guard the main paths leading to their base. In the center of each base is the “Ancient”, a building that must be destroyed to win the game.^[4][5]

Each human player controls one Hero, a powerful unit with unique abilities. In Allstars, players on each side choose one of ninety-five heroes, each with different abilities and tactical advantages over other heroes.^[6] The scenario is highly team-oriented; it is difficult for one player to carry the team to victory alone.^[7] Nevertheless, some heroes, given enough time, can change the outcome single-handedly, while countering the opposing team’s heroes. Defense of the Ancients allows up to ten players in a five versus five format and an additional two slots for referees or observers, often with an equal number of players on each side.

Because the gameplay revolves around strengthening individual heroes, it does not require one to focus on resource management and base-building, as in most traditional real-time strategy games. Killing computer-controlled or neutral units earns the player experience points; when enough experience is accumulated, the player gains a level. Leveling up improves the hero’s toughness and the damage it can inflict, and allows players to upgrade their spells or skills. In addition to accumulating experience, players also manage a single resource: gold. The typical resource gathering of Warcraft III is replaced by a combat-oriented money system; in addition to a small periodic income, heroes earn gold by killing hostile units, base structures, and enemy heroes.^[8] Using gold, players buy items to strengthen their hero and gain abilities. Certain items can be combined with recipes to create more powerful items. Buying items that suit one’s hero is an important tactical element of the scenario.^[9]

Allstars offers a variety of game modes, selected by the game host at the beginning of the match. The game modes dictate the difficulty of the scenario, as well as whether people can choose their hero or are assigned one randomly. Many game modes can be combined (for example, an easy difficulty level and a random hero pick), allowing more flexible options.^[10]

Development

Warcraft III is the third title in the Warcraft series of real-time strategy games developed by Blizzard Entertainment. As with Warcraft II, Blizzard included a free “world editor” in the game that allows players to create custom scenarios or “maps” for the game, which can be played online with other players through Battle.net.^[11] These custom scenarios can be simple terrain changes, which play like normal Warcraft games, or they can be entirely new game scenarios with custom objectives, units, items, and events, like Defense of the Ancients.^[11]

The first version of Defense of the Ancients was released in 2003 by a mapmaker under the alias Eul,^[12] who based the map on a previous StarCraft scenario known as “Aeon of Strife”,^[10] After the release of Warcraft‘s expansion The Frozen Throne, which added new features to the World Editor, Eul did not update the scenario.^[13] Other mapmakers produced spinoffs that added new heroes, items, and features.^[12]

Among the DotA variants created in the wake of Eul’s map included Allstars, developed by modder Steve Feak (under the alias Guinsoo); this version would become the most popular version of the map.^[14] Feak said when he began developing Allstars he had no idea how popular the game would eventually become; the emerging success of the gametype inspired him to design a new title around what he considered an emerging game genre.^[15] Feak added a recipe system for items so that player’s equipment would scale as they grew more powerful, as well as a powerful boss character called Roshan (named after his bowling ball) who required an entire team to defeat.^[12]

Feak used a battle.net chat channel as a place for DotA players to congregate,^[12] but DotA Allstars had no official site for discussions and hosting. The leaders of the DotA Allstars clan, TDA, proposed that a dedicated web site be created to replace the various online alternatives that were infrequently updated or improperly maintained. TDA member Steve “Pendragon” Mescon created the official community site, dota-allstars.com, on October 14, 2004.^[16]

Towards the end of his association with the map, Feak primarily worked on optimizing the map before handing over control to another developer after version 6.01. The new author, IceFrog, added new features, heroes, and fixes. Each release is accompanied with a changelog.^[17] IceFrog is notoriously reclusive, refusing to give interviews; the only evidence of IceFrog’s authorship was the map maker’s email account on the official website and the name branded on the game’s loading screen.^[3] Icefrog now interacts with players through a personal blog where he answers common questions players have about him and about the game.^[18] He has also posted information about upcoming map releases, including previews of new heroes and items.^[19]

Defense of the Ancients is maintained via official forums. Users can post ideas for new heroes or items, some of which are added to the map. Players have contributed icons and hero descriptions and created the artwork displayed while the map loads, and suggestions for changes to existing heroes or items are taken seriously; IceFrog once changed a new hero less than two weeks after the new version of the map was released.^[3] Versions of the scenario where enemy heroes are controlled by artificial intelligences have also been released. Mescon continues to maintain dota-allstars.com, which as of April 2009 has 1.5 million registered members and receives more than a million unique visitors each month. New team members have been added to roll out visual and system improvements to the site.^[16] IceFrog announced due to conflict of interest that he would be boycotting dota-allstars.com and starting his own web site while continuing game development.^[20]

Because Warcraft III custom games have none of the features designed to improve game quality (matchmaking players based on connection speed, etc.), various programs are used to maintain Defense of the Ancients. External tools ping player’s locations, and games can be named to exclude geographic regions.^[3] Clans and committees such as TDA maintain their own official list of rules and regulations, and players can be kicked from matches by being placed on “banlists”.^[3]

Reception and legacy

The top three finalists from the first World Cyber Games Defense of the Ancients championship

The popularity of Defense of the Ancients has increased over time. The scenario was featured by Computer Gaming World in a review of new maps and mods in Warcraft III,^[21] and has been called “the ultimate RTS” by game journalist and developer Luke Smith.^[22] Allstars has become an important tournament scenario, starting with its prominence at the debut of Blizzard’s BlizzCon convention in 2005.^[23] Allstars was also featured in the Malaysia and Singapore World Cyber Games starting in 2005, and the World Cyber Games Asian Championships beginning with the 2006 season.^[24] Defense of the Ancients is now included in the game lineup for the internationally recognized Cyberathlete Amateur League and CyberEvolution leagues.^[25] Additionally, the scenario appeared in Electronic Sports World Cup (ESWC) 2008;^[26][27] Oliver Paradis, ESWC’s competition manager, noted that the high level of community support behind the scenario, as well as its worldwide appeal, were among the reasons it was chosen.^[28]

The scenario is popular in many parts of the world; in the Philippines and Thailand, it is played as much as the game Counter-Strike.^[29] It is also popular in Sweden and other Northern European countries, where the Defense of the Ancients-inspired song “Vi sitter i Ventrilo och spelar DotA” by Swedish musician Basshunter reached the European 2006 charts at #116 and cracked the top ten Singles Charts in Sweden, Norway,^[30] and Finland.^[31] LAN tournaments are a major part of worldwide play,^[28] including tournaments in Sweden and Russia; however, due to a lack of LAN tournaments and championships in North America, several teams have since disbanded.^[29] Blizzard points to DotA as an example of what dedicated mapmakers can create using developer’s tools.^[32]

In June 2008, Michael Walbridge, writing for Gamasutra, stated that DotA “is likely the most popular and most-discussed free, non-supported game mod in the world”.^[3] In pointing to the strong community built around the game, Walbridge stated that DotA shows it is much easier for a community game to be maintained by the community, and this is one of the maps’ greatest strengths. Defense of the Ancients has been credited as one of the influences for the 2009 Gas Powered Games title Demigod,^[33][34] with the video game publication GameSpy noting the game’s premise revolved around aspiring gods “[playing] DotA in real life”.^[35] Guinsoo went on to apply many of the mechanics and lessons he learned from Defense of the Ancients to the upcoming Riot Games title League of Legends: Clash of Fates.^[15] Other “DotA clones” include S2 Games‘ Heroes of Newerth.^[36]