武汉理工道桥毕业设计英文翻译.doc

Bridge Engineering RAMANKUTTY KANNANKUTTY, City of Minneapolis Department of Public Works DONALD J. FLEMMING, Minnesota Department of Transportation The scope of the Transportation Research Board’s (TRBs) Committee on General Structures includes factors affecting the physical behavior, service life, economy, appearance, and safety of bridges and structures for transportation systems, and accounting for these factors and their interactions in design procedures and criteria. During the 20th century the United States has essentially created the safest, most efficient, and most effective highway and intermodal transportation network in the world. The challenge for the new millennium will be to further enhance this transportation network. In this paper the status of bridge engineering at the end of the 20th century in the area of general transportation structures is summarized. The focus is on bridge structure types, design aspects, new materials, aesthetic concerns, and key policy issues. An attempt is made to forecast the status of bridge engineering 20 to 30 years into the next millennium; the paper is written as though these forecasts will become a reality. BRIDGE STRUCTURE TYPES Structure types have been evolving throughout history. The evolution will continue into the future, perhaps at an accelerated rate.The driving forces behind continued advances in bridge engineering are traffic congestion and costs. In the future, just as now, the public will expect few traffic delays, if any. They will want transportation costs to be as low as possible. Computer technology will enhance traffic management so well that the public will become accustomed to flowing traffic and more aware of congestion locations. Disruptions from construction will be more obvious and even less tolerated. Given these conditions, structural types will be selected primarily on the basis of speed of construction to minimize traffic delays. Low maintenance will be a must, and the ability to widen a st