外文翻譯--一個良好的公路的基礎(chǔ)-公路隧道-全文預(yù)覽
【正文】 has a mix of sizes (wellgraded aggregate) so smaller particles can fill the voids between larger ones. Good paction of asphalt pavement lengthens its life. 5． Design for traffic loads and volumes Design for the highest anticipated load the road will carry. A road that has been designed only for cars will not stand up to trucks. One truck with 9 tons on a single rear axle does as much damage to a road as nearly 10,000 cars. Rural roads may carry log trucks, milk trucks, fire department pumper trucks, or construction equipment. If you don’t know what specific loads the road will carry, a good rule of thumb is to design for the largest piece of highway maintenance equipment that will be used on the road. A wellconstructed and maintained asphalt road should last 20 years without major repairs or reconstruction. In designing a road, use traffic counts that project numbers and sizes of vehicles 20 years into the future. These are only projections, at best, but they will allow you to plan for traffic 河南理工大學(xué) 09 級交通工程專業(yè)外文翻譯 2020 4 loadings through a road’s life. 6． Design for maintenance Without maintenance a road will rapidly deteriorate and fail. Design your roads so they can be easily maintained. This means: ? adequate ditches that can be cleaned regularly ? culverts that are marked for easy locating in the spring ? enough space for snow after it is plowed off the road ? proper cross slopes for safety, maintenance and to avoid snow drifts ? roadsides that are planted or treated to prevent erosion ? roadsides that can be mowed safely A rule of thumb for adequate road width is to make it wide enough for a snowplow to pass another vehicle without leaving the travelled way. Mark culverts with a post so they can be located easily. 7． Pave only when ready It is not necessary to pave all your roads immediately. There is nothing wrong with a wellbuilt and wellmaintained gravel road if traffic loads and volume do not require a paved surface. Three hundred vehicles per day is the remended minimum to justify paving. Don’t assume that laying down asphalt will fix a gravel road that is failing. Before you pave, make sure you have an adequate crushed stone base that drains well and is properly pacted. The remended minimum depth of crushed stone base is 10 depending on subgrade soils. A road paved only when it is ready will far outperform one that is constructed too quickly. 8． 202。 remove all excess material Roadside — cut brush, trim trees and roadside plantings, control erosion Traffic service — clean and repair or replace signs Design roads with adequate ditches so they can be maintained with a motor grader. Clean and grade ditches to maintain proper pitch and peak efficiency. After grading, remove all excess material from the shoulder. 10． Keep good records Your maintenance will be more efficient with good records. Knowing the road’s construction, life, and repair history makes it much easier to plan and budget its future repairs. Records can also help you evaluate the effectiveness of the repair methods and materials you used. Good record keeping starts with an inventory of the system. It should include the
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