柬埔寨日常用语很爽:翻译英译汉

STEPHEN B. SEEDS, Nichols Consulting Engineers, Reno, Nevada
Contained within this paper is a summary description of the state of the art in flexible
pavement design along with a look to the future in terms of some specific technical needs, the translation of the new technology into practice, and making flexible pavement design (or pavement engineering in general) a more credible discipline. Since the scope of the
Committee on Flexible Pavement Design focuses upon the improvement of flexible
pavement design (with particular emphasis on closing the gap between the state of the art
and the state of the practice), these are issues that can be well addressed at this time.
OVERVIEW
Keeping in mind that flexible pavement design deals primarily with structural aspects (i.e., the selection of appropriate materials, characterization of strength or load-carrying
properties, layer thickness determination), it can be said that the state of the art in flexible
pavement design is manifested in mechanistic, or mechanistic-empirical (M-E), based design procedures that incorporate the treatment of life-cycle costs and design reliability. State-of-the-practice methods, on the other hand, tend to rely more on empirical correlations with past performance, index-value-based characterizations of material properties [layer coefficient, R-value, California bearing ratio (CBR), etc.], and engineering judgment for design strategy selection. [Note: In this context, mechanistic design procedures refer to those methods that incorporate models based on fundamental engineering mechanics to evaluate the state of stress in a pavement and predict response, behavior, and performance. Empirical procedures are those that rely more on models developed from experience or observations of past performance.] In addition, these procedures have been used at traffic load levels and in environments well beyond their observational base. The Guide for Design of Pavement Structures published by the American Association of State Highway and Transportation Officials (AASHTO) is commonly used to design pavement with traffic loadings greater than 50 million equivalent single-axle loads (ESALs), but the basic design equations were developed from traffic loadings of less than 2 million ESALs.