Harbours and sea works, harbour also spelled harbor, any part of a body of water and the manmade structures surrounding it that sufficiently shelters a vessel from wind, waves, and currents, enabling safe anchorage or the discharge and loading of cargo and passengers. Lorient The construction of harbours and sea works offers some of the most unusual problems and…
Canals and inland waterways, natural or artificial waterways used for navigation, crop irrigation, water supply, or drainage. Despite modern technological advances in air and ground transportation, inland waterways continue to fill a vital role and, in many areas, to grow substantially. This article traces the history of canal building from the earliest times to the present day and describes both…
Bridge, structure that spans horizontally between supports, whose function is to carry vertical loads. The prototypical bridge is quite simple—two supports holding up a beam—yet the engineering problems that must be overcome even in this simple form are inherent in every bridge: the supports must be strong enough to hold the structure up, and the span between supports must…
The Romans had realized that a coordinated system of roadways connecting the major areas of their empire would be of prime significance for both commercial and military purposes. In the modern era, the nations of Europe first introduced the concept of highway systems. In France, for example, the State Department of Roads and Bridges was organized…
The parkway The achievement of such a system in the automobile age required a new form of road. This grew from the parkway, which had many historical precedents but was introduced in its modern form in 1858 with the work of the landscape architects Frederick Law Olmsted and Calvert Vaux for Central Park in New York City. The concept was given…
From corvée to toll Through the millennia, responsibility for financing and building roads and highways has been both a local and a national responsibility in the nations of the world. It is notable that this responsibility has changed along with political attitudes toward road building and has not rested easily with any party. Many roads…
When urban street paving became widespread in the latter half of the 19th century, the common paving materials were hoof-sized stone blocks, similarly sized wooden blocks, bricks, McAdam’s broken stone, and occasionally asphalt and concrete. McAdam’s broken stone provided the cheapest pavement, but its unbound surface was difficult to maintain and was usually either slimy or dusty…
Beginning in the 1840s, the rapid development of railroads brought the construction of lightweight Trésaguet-McAdam roads to a virtual halt. For the next 60 years, road improvements were essentially confined to city streets or to feeder roads to railheads. Other rural roads became impassable in wet weather. The initial stimulus for a renewal of road…
The Lancaster Turnpike The first engineered and planned road in the United States was the Lancaster Turnpike, a privately constructed toll road built between 1793 and 1795. Connecting Philadelphia and Lancaster in Pennsylvania, its 62-mile length had a maximum grade of 7 percent and was surfaced with broken stone and gravel in a manner initially uninfluenced by the…
The master road builders In Europe, gradual technological improvements in the 17th and 18th centuries saw increased commercial travel, improved vehicles, and the breeding of better horses. These factors created an incessant demand for better roads, and supply and invention both rose to meet that demand. In 1585 the Italian engineer Guido Toglietta wrote a thoughtful treatise on a…