Infrastructure is the fundamental facilities and systems serving a country, city, or other area, including the services and facilities necessary for its economy to function. Infrastructure is composed of public and private physical improvements such as roads, railways, bridges, tunnels, water supply, sewers, electrical grids, and telecommunications (including Internet connectivity and broadband speeds). In general, it has also been defined as "the physical components of interrelated systems providing commodities and services essential to enable, sustain, or enhance societal living conditions".
There are two general types of ways to view infrastructure, hard or soft. Hard infrastructure refers to the physical networks necessary for the functioning of a modern industry. This includes roads, bridges, railways, etc. Soft infrastructure refers to all the institutions that maintain the economic, health, social, and cultural standards of a country. This includes educational programs, official statistics, parks and recreational facilities, law enforcement agencies, and emergency services.
The word infrastructure has been used in French since 1875 and in English since 1887, originally meaning "The installations that form the basis for any operation or system". The word was imported from French, where it was already used for establishing a roadbed of substrate material, required before railroad tracks or constructed pavement could be laid on top of it. The word is a combination of the Latin prefix "infra", meaning "below" and many of these constructions are underground, for example, tunnels, water and gas systems, and railways and the French word "structure" (derived from the Latin word "structura"). The army use of the term achieved currency in the United States after the formation of NATO in the 1940s, and by 1970 was adopted by urban planners in its modern civilian sense.
Road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past cobblestones and granite setts were extensively used, but these surfaces have mostly been replaced by asphalt or concrete. Such surfaces are frequently marked to guide traffic. Today, permeable paving methods are beginning to be used for low-impact roadways and walkways.
Asphalt (specifically, asphalt concrete) has been widely used since 1920–1930. The viscous nature of the bitumen binder allows asphalt concrete to sustain significant plastic deformation, although fatigue from repeated loading over time is the most common failure mechanism. Most asphalt surfaces are laid on a gravel base, which is generally at least as thick as the asphalt layer, although some full depth asphalt surfaces are laid directly on the native subgrade. In areas with very soft or expansive subgrades such as clay or peat, thick gravel bases or stabilization of the subgrade with Portland cement or lime may be required. Polypropylene and polyester materials have also been used for this purpose. An asphalt concrete surface will generally be constructed for high volume primary highways having an average annual daily traffic load higher than 1200 vehicles per day. Advantages of asphalt roadways include relatively low noise, relatively low cost compared with other paving methods, and perceived ease of repair. Disadvantages include less durability than other paving methods, less tensile strength than concrete, the tendency to become slick and soft in hot weather and a certain amount of hydrocarbon pollution to soil and groundwater or waterways.
As pavement systems primarily fail due to fatigue (in a manner similar to metals), the damage done to pavement increases with the fourth power of the axle load of the vehicles traveling on it. Civil engineers consider truck axle load, current and projected truck traffic volume, supporting soil properties (can be measured using the CBR) and sub-grade drainage in design. Passenger cars are considered to have no practical effect on a pavement's service life, from a fatigue perspective. Other failure modes include aging and surface abrasion. As years go by, the binder in a bituminous wearing course gets stiffer and less flexible. When it gets old enough, the surface will start losing aggregates, and macrotexture depth increases dramatically. If no maintenance action is done quickly on the wearing course potholing will take place. If the road is still structurally sound, a bituminous surface treatment, such as a chipseal or surface dressing can prolong the life of the road at low cost. In areas with cold climate, studded tires may be allowed on passenger cars. In Sweden and Finland, studded passenger car tires account for a very large share of pavement rutting.
Graphical phases in the life cycle of a facility
Public Vs. Private Provision
Benjamin Wright (October 10, 1770 – August 24, 1842) was a noted American civil engineer who served as Chief Engineer of both the Erie Canal and Chesapeake and Ohio Canal. In 1969 he was declared the Father of American Civil Engineering by the American Society of Civil Engineers. In 1789, at age 19, he moved with his family to Rome, New York where he became a surveyor. In 1794, at age 24, he was hired as a surveyor and planner by the famed English canal designer William Weston. Working for Weston, he helped lay out canals and locks on the Mohawk River. After Weston returned to England in 1790, Wright was commissioned to survey the Mohawk River between Schenectady and Rome, New York, and then from Rome to the Hudson River.
In 1816 funding for the Erie Canal was in place, and in 1817, Wright was named Chief Engineer. In this position he led thousands of unskilled laborers as they built the canal with the aid of wheelbarrows, hand tools, horses, and mules. In Wright's honor, the first boat to traverse the canal system was named the Chief Engineer. After completion of the Erie Canal, he was approached by the Wurts brothers of Philadelphia to survey a possible route from the coalfields of Northeastern Pennsylvania to the Hudson, where anthracite could be shipped by boat downriver to New York City. This became the Delaware and Hudson Canal, and remained in operation until 1898. When that canal was finished in 1828, Wright was made Chief Engineer of the newly organized Chesapeake and Ohio Canal. Within a year, Wright had let contracts for a massive construction effort that encompassed about 6,000 men and 700 horses.