土木工程毕业设计中英文翻译

土木工程毕业设计中英文翻译内容摘要：

and estimated cost of construction for the various plans. The photogrammetric method, which makes use of aerial photographs is used extensively to indicate the character of the terrain on large projects where it is most economical. On small project, Financing considerations determine whether the project can be carried out t\t one time or whether construction must be in stages with each stage initiated as funds bee available. In deciding the best method of financing the work, the engineer makes an analysis of whom it will benefit. Important highways and streets benefit* in varying degrees, three groups* users owners of adjacent property and the general public. Users of improved highways benefit from decreased cost of transportation, greater travel fort, increased safety and saving of time. They also obtain recreational and educational benefits. Owners of abutting or adjacent property may benefit from better access, increased property value, more effective police and fire protection, improved street parking greater pedestrian traffic safety, and the use of the street rightofway for the location of public utilities such as water lines and sewers. Evaluation of various benefits from highway construction is often difficult but is a most important phase of highway engineering. Some benefits can be measured with accuracy, but the evaluation of others is more speculative. As a result numerous methods arc used to finance construction, and much engineering work may he involved in selecting the best procedure. Environmental evaluation. The environmental impact of constructing highways has received increased attention and importance. Many projects have been delayed and numerous others canceled because ot environmental problems. The environmental study or report covers many factors, including noise generation, air pollution disturbance of areas traversed destruction of existing housing and possible alternate routes. Highway engineers must also assist in the acquisition of rightofway needed for new highway facilities Acquisition of the land required for construction of expressway lending into the central business areas of cities has proved extremely difficult i the public is demanding that traffic engineers work closely with city planners, architects, sociologists and all groups interested in beautification and improvement of cities to assure that expressways extendinx through metropolitan areas be built only after coordinated evaluation of all major questions, including the following。 (1) Is sufficient attention being paid to beautification of the expressway itself? (2) Would a change in location preserve major natural beauties of the city? (3) Could a depressed design he logically substituted for those sections where an elevated expressway is proposed? (4) Can the general design he improved to reduce the noise created by large volumes of traffic? ( 5) Are some sections of the city being isolated by the proposed location? Detailed design. Detailed design of a highway project includes preparation of drawings or blueprints to be used for construction. These plans show, for example, the location, the dimensions of such elements as roudway width* the finaj profile for (he road, the location and type of drainage facilities, and the quantities of work involved, including earthwork and surfacing. In planning the grading operations the design engineer considers the type of material to be encountered in excavating or in cutting away the high points along the project and how the rnaterial removed can best be utilised for fill or for constructing embankments across low areas elsewhere on the project. For this the engineer must analyze the gradation and physical properties of the soil, determine how the embankments can best be pacted, and calculate the volume of earthwork to be done. Electronic calculating procedures are now sometimes used for the last step. Electronic equipment has also speeded up many other highway engineering calculations. Powerful and highly mobile earth moving machines have been developed TO permit rapid and economical operations. , Selection of the type and thickness of roudway surfacing to be constructed is an important part of design. The type chosen depends upon the maximum loads to be acmodated, the frequency of these loads and other factors. For some mures, traffic volume may be so low that no surfacing is economically justified and natural soil serves as the roadway. As traffic increases, a surfacing of sandy cluy, crushed slag, crushed stone caliche crushed oyster shells, or a bination of these may be applied. If gravel is used, it usually contains sufficient clay and fine material to help stabilize the surfacing. Gravel surfaces may be further stubilized by application of calcium chloride, which also aids in controlling dust. Another surfacing is posed of Portland cement and water mixed iuto the upper few inches of the suhgrade and pacted with rollers. This procedure forms A soilcement base that can be surfaced with bituminous materials. Roadways ro carry large volumes of heavy vehicles must be carefully designed and made of。