Infrastructure can be defined as the basic physical and organizational structures needed for the operation of a society or enterprise, or the services and facilities necessary for an economy to function. The term typically refers to the technical structures that support a society, such as roads, water supply, sewers, power grids, telecommunications, and so forth. Viewed functionally, infrastructure facilitates the production of goods and services; for example, roads enable the transport of raw materials to a factory, and also for the distribution of finished products to markets. In some contexts, the term may also include basic social services such as schools and hospitals . In military parlance, the term refers to the buildings and permanent installations necessary for the support, redeployment, and operation of military forces .
In this article, infrastructure will be used in the sense of technical structures or physical networks that support society, unless specified otherwise.
According to etymology online , the word infrastructure has been used in English since at least 1927 and meant: The installations that form the basis for any operation or system. Other sources, such as the Oxford English Dictionary, trace the word's origins to earlier usage, originally applied in a military sense. The word was imported from French, where it means subgrade, the native material underneath a constructed pavement or railway. The word is a combination of the Latin prefix "infra", meaning "below" and "structure". The military sense of the word was probably first used in France, and imported into English around the time of the First World War. The military use of the term achieved currency in the
The term came to prominence in the
That public-policy discussion was hampered by lack of a precise definition for infrastructure. A U.S. National Research Council panel sought to clarify the situation by adopting the term "public works infrastructure", referring to:
"...both specific functional modes - highways, streets, roads, and bridges; mass transit; airports and airways; water supply and water resources; wastewater management; solid-waste treatment and disposal; electric power generation and transmission; telecommunications; and hazardous waste management - and the combined system these modal elements comprise. A comprehension of infrastructure spans not only these public works facilities, but also the operating procedures, management practices, and development policies that interact together with societal demand and the physical world to facilitate the transport of people and goods, provision of water for drinking and a variety of other uses, safe disposal of society's waste products, provision of energy where it is needed, and transmission of information within and between communities."
In subsequent years, the word has grown in popularity and been applied with increasing generality to suggest the internal framework discernible in any technology system or business organization.
The 2009 report card produced by the American Society of Civil Engineers gives
Various uses of the term
Engineering and construction
Engineers generally limit the use of the term infrastructure to describe fixed assets that are in the form of a large network. Recent efforts to devise more generic definitions of infrastructure have typically referred to the network aspects of most of the structures and to the accumulated value of investments in the networks as assets. One such effort defines infrastructure as the network of assets "where the system as a whole is intended to be maintained indefinitely at a specified standard of service by the continuing replacement and refurbishment of its components." However, the principles that civil infrastructure is meant to have unlimited service life and always provide some specified minimum standard of service are neither inherent to the concept nor generally accepted by the societies served.
Civil defense and economic development
Civil defense planners and developmental economists may use a broad definition that includes public services such as schools and hospitals, emergency services such as police and fire fighting, and basic financial services.
Military
Military strategists use the term infrastructure to refer to all building and permanent installations necessary for the support of military forces, whether they are stationed in bases, being deployed or engaged in operations, such as barracks, headquarters, airfields, communications facilities, stores of military equipment, port installations, and maintenance stations .
Critical infrastructure
Main article: critical infrastructure
The term critical infrastructure has been widely adopted to distinguish those infrastructure elements that, if significantly damaged or destroyed, would cause serious disruption of the dependent system or organization. Storm, flood, or earthquake damage leading to loss of certain transportation routes in a city (for example, bridges crossing a river), could make it impossible for people to evacuate and for emergency services to operate; these routes would be deemed critical infrastructure. Similarly, an on-line booking system might be critical infrastructure for an airline.
Urban infrastructure
Urban or municipal infrastructure refers to systems generally owned and operated by municipalities, such as streets, water distribution, sewers, etc.
Other uses
In other applications, the term infrastructure may refer to information technology, informal and formal channels of communication, software development tools, political and social networks, or beliefs held by members of particular groups. Still underlying these more conceptual uses is the idea that infrastructure provides organizing structure and support for the system or organization it serves, whether it is a city, a nation, a corporation, or a collection of people with common interests. Examples: IT infrastructure, research infrastructure, terrorist infrastructure, tourism infrastructure.
Related concepts
Land improvement and land development
The terms land improvement and land development are a general terms that in some contexts may include infrastructure, but in the context of a discussion of infrastructure would refer only to smaller scale systems or works that are not included in infrastructure because they are typically limited to a single parcel of land, and are owned and operated by the land owner. For example, an irrigation canal that serves a region or district would be included with infrastructure, but the private irrigation systems on individual land parcels would be considered land improvements, not infrastructure. Service connections to municipal service and public utility networks would also be considered land improvements, not infrastructure.
Public works and public services
The term public works includes government owned and operated infrastructure as well as public buildings such as schools and court houses. The term public works generally refers to physical assets needed to deliver public services.
Public services include both infrastructure and services generally provided by government.
Typical attributes
Capital assets that provide services
They are physical assets that provide services;
The people employed in the infrastructure sector generally maintain, monitor and operate the assets, but do not offer services to the clients or users of the infrastructure. Interactions between workers and clients are generally limited to administrative tasks concerning ordering, scheduling or billing of services.
Large networks
They are large networks constructed over generations, and are not often replaced as a whole system.
The network provides services to a geographically defined area.
The system or network has a long life because its service capacity is maintained by continual refurbishment or replacement of components as they wear out.
Historicity and interdependence
The system or network tends to evolve over time as it is continuously modified, improved, enlarged, and as various components are re-built, decommissioned or adapted to other uses.
The system components are interdependent and not usually capable of subdivision or separate disposal, and consequently are not readily disposable within the commercial marketplace.
The system interdependency may limit a component life to a lesser period than the expected life of the component itself.
Natural monopoly
The systems tend to be natural monopolies, insofar that economies of scale means that multiple agencies providing a service are less efficient than would be the case if a single agency provided the service.
The assets have a high initial cost and a value that is difficult to determine.
Once most of the system is built, the marginal cost of servicing additional clients or users tends to be relatively inexpensive, and may be negligeable if there is no need to increase the peak capacity or the geographical extent of the network.
Types of infrastructure
The following list is limited to capital assets that serve the function of conveyance or channelling of people, vehicles, fluids, energy or information, and which take the form either of a network or of a critical node used by vehicles, or used for the transmission of electro-magnetic waves. Infrastructure systems include both the fixed assets and the control systems and software required to operate, manage and monitor the systems, as well as any accessory buildings, plants or vehicles that are an essential part of the system.
Transportation infrastructure
Road and highway networks, including structures (bridges, tunnels, culverts, retaining walls), signage and markings, electrical systems (street lighting and traffic lights) and edge treatments (curbs, sidewalks, landscaping)
Railways, including structures, terminal facilities (railyards, train stations), level crossings, signalling and communications systems
Canals and navigable waterways requiring continuous maintenance (dredging, etc.)
Seaports and lighthouses
Airports, including air navigational systems
Mass transit systems (Commuter rail systems, subways, tramways, trolleys and bus terminals)
Bicycle paths and pedestrian walkways
Energy infrastructure
Electrical power network, including generation plants, electric grid, substations and local distribution
Natural gas pipelines, storage and distribution terminals, as well as the local distribution network
Petroleum pipelines, including associated storage and distribution terminals
Steam or hot water production and distribution networks for district heating systems
Water management infrastructure
Drinking water supply, including the system of pipes, pumps, valves, filtration and treatment equipment and meters, including buildings and structures to house the equipment, used for the collection, treatment and distribution of drinking water
Sewage collection and disposal
Drainage systems (storm sewers, ditches, etc..)
Major irrigation systems (reservoirs, irrigation canals)
Major flood control systems (dikes, levees, major pumping stations and floodgates)
Communications infrastructure
Telephone networks (land lines) including switching systems
Mobile phone networks
Cable television networks including receiving stations and cable distribution networks
Internet backbone, including high-speed data cables, routers and servers as well as the protocols and other basic software required for the system to function
Communication satellites
Undersea cables
Major private, government or dedicated telecommunications networks, such as those used for internal communication and monitoring by major infrastructure companies, by governments, by the military or by emergency services
Pneumatic tube mail distribution networks
Waste management facilities
Solid waste landfills
Solid waste incinerators
Hazardous waste disposal facilities;
Geophysical monitoring networks
Meteorological monitoring networks
Tidal and fluviometric monitoring networks
Seismometer networks
Remote sensing satellites
Other systems or networks
Global Positioning System
Note that certain systems or facilities that are similar to infrastructure are not included in this list because they are essentially services performed by people (commuter bus services, garbage collection services, emergency services) or they are facilities that are not necessarily part of or in the form of a network (parks, sports facilities), or they are essentially privately-owned industrial plants that do not necessarily depend on a fixed distribution network (oil refineries). However solid waste disposal facilities were included because they are often the critical nodal points of a network-like public service (garbage collection), and are usually publicly owned or heavily regulated. Telecommunication systems are included if their function is limited to the conveyance of information (telephone system), but not if their function includes supplying the content of that information (TV or radio networks).
Economics, Management and Engineering
Infrastructure may be owned and managed by governments or by private companies, such as public utility or railway companies. Generally, most roads, major ports and airports, water distribution systems and sewage networks are publicly owned, whereas most energy and telecommunications networks are privately owned. Publicly owned infrastructure may be paid for from taxes, tolls or metered user fees, whereas private infrastructure is generally paid for by metered user fees. Major investment projects are generally financed by the issuance of long-term bonds.
Note that government owned and operated infrastructure may be developed and operated in the private sector or in public-private partnership in addition to in the public sector.
In the
Planning and Management
The key components of 'Infrastructure Asset Management' are:
Definition of a Standard of Service
Establishment of measurable specifications of how the asset should perform
Establishment of a minimum condition grade
Establishment of a whole-life cost approach to managing the asset
Elaboration of an Asset Management Plan
Engineering
Most infrastructure is designed by civil engineers, except for telecommunications, electricity and monitoring networks, that are designed mainly by electrical engineers. In the case of urban infrastructure, the general layout of roads, sidewalks and public placed may sometimes be designed by urbanists or architects, although the detailed design will still be performed by civil engineers.
In terms of engineering tasks, the design and construction management process usually follows these steps:
Preliminary Studies:
Determine existing and future traffic loads, determine existing capacity, and estimate the existing and future standards of service;
Conduct a preliminary survey and obtain information from existing air photos, maps, plans, etc.
Identify possible conflicts with other assets or topographical features;
Perform environmental impact studies:
Evaluate the impact on the human environment (Noise pollution, odors, electromagnetic interference, etc..);
Evaluate the impact on the natural environment (disturbance of natural ecosystems);
Evaluate possible presence of contaminated soils;
Given various time horizons, standards of service, environmental impacts and conflicts with existing structures or terrain, propose various preliminary designs;
Estimate the costs of the various designs, and make recommendations;
Detailed Survey:
Perform a detailed survey of the construction site;
Obtain As Built drawings of existing infrastructure;
Dig exploratory pits where required to survey underground infrastructure;
Perform a geotechnical survey to determine the bearing capacity of soils and rock;
Perform soil sampling and testing to estimate nature, degree and extent of soil contamination;
Detailed Engineering:
Prepare detailed plans and technical specifications;
Prepare a detailed bill of materials;
Prepare a detailed cost estimate;
Establish a general work schedule;
Authorization:
Obtain authorization from environmental and other regulatory agencies;
Obtain authorization from any owners or operators of assets affected by the work;
Inform emergency services, and prepare contingency plans in case of emergencies;
Tendering:
Prepare administrative clauses and other tendering documents;
Organize and announce a Call for Tenders;
Answer contractor questions and issue addenda during the tendering process;
Receive and analyse tenders, and make a recommendation to the owner;
Construction Supervision:
Once the construction contract has been signed between the owner and the general contractor, once all authorisations have been obtained, and once all pre-construction submittals have been received from the general contractor, the construction supervisor issues an Order to Begin Construction;
Regularly schedule meetings and obtain contact information for the general contractor (GC) and all interested parties;
Obtain a detailed work schedule and list of subcontractors from the GC.
Obtain detailed traffic diversion and emergency plans from the GC;
Obtain proof of certification, insurance and bonds;
Examine shop drawings submitted by the GC;
Receive reports from the materials quality control lab;
When required, review Change requests from the GC, and issue Construction Directives and Change Orders;
Follow work progress and authorize partial payments;
When substantially completed, inspect the work and prepare a list of deficiencies;
Supervise testing and commissionning;
Verify that all operating and maintenance manuals, as well as warranties, are complete;
Prepare "As Built" drawings;
Make a final inspection, issue a certificate of final completion and authorize the final payment.
Impact on Economic Development
Investment in infrastructure is part of the capital accummulation required for economic development.
Use as Economic stimulus
During the Great Depression of the 1930s, many governments undertook public works projects in order to create jobs and stimulate the economy. The economist John Maynard Keynes provided a theoretical justification for this policy in the The General Theory of Employment, Interest and Money , published in 1936. Following the global financial crisis of 2008–2009, some are again proposing investing in infrastructure as a means of stimulating the economy (see the American Recovery and Reinvestment Act of 2009)
