Composites got a real test of their use as an infrastructure material last June, when beams of fibreglass, carbon and resin were used to replace the steel in a bridge in Blacksburg, Virginia, in the USA that carries 1 000 cars each day. The Tom's Creek Bridge was one of the first composite structures in the US to carry regular automobile traffic. The old steel-framed bridge, which had corroded to the point where load limits had to. be lowered, was due to be replaced when the town of Blacksburg was approached by researchers from Virginia Tech, the Virginia Department of Transport and the Virginia Transportation Research Council, who proposed replacing the bridge with an HS-20 strength design featuring composites.
What effect would accepting the concept of sustainable development have on the way engineers work? What does the concept of sustainable development mean to civil engineers? Do they use it seriously or unthinkingly? This paper will attempt to show that sustainable development could have a very fundamental meaning, so fundamental that it may touch the raison d'etre of civil engineering itself.
Crossing Tokyo Bay and some of the world's busiest shipping lanes via a 10 km tunnel and 5 km bridge, this link brings Chiba and Kanagawa prefectures to within 15 minutes of each other. Before, ferry and road journeys could take more than 10 times that long. While the project is a masterpiece of civil engineering and its long-term impact should be profound, some have questioned its price tag of US$11 billion and whether it will ever be a paying proposition. But, as with similar criticism directed at the cross-channel 'Chunnel' connecting Britain and the Continent, backers can make eminently sensible counterclaims that the real value of such projects cannot be measured merely on a balance sheet.
Innovative techniques were used to ensure the continued viability of a vital regional link to schools, shops and farming activities land River Bridge No 86 south of Welkom in the Free State was constructed in 1921. The mass concrete (1 :2:4) abutments and the central pier were founded on large concrete (1 :3:6) caissons (8,6 m by 3,35 m) at a depth of about 5 m below river bed level onto a boulder bed, which prohibited further sinking.
The aim of this paper is to sketch the elementary principles of the science of photogrammetry, showing how the use of stereoscopy makes it possible to compile accurate topographical maps from photographs. After brief mention of the instruments and processes involved, data are given indicating standards of accuracy attainable. Comparisons are made with ground survey methods and costs, and reference is made to a number of applications to engineering survey problems of various kinds. As the subject is vast, its treatment must of necessity be somewhat superficial.