CEBU INSTITUTE OF TECHNOLOGY - UNIVERSITYCollege of Engineering and ArchitectureDepartment of Civil Engineering1.INTRODUCTIONThe structural designof thetravelway of any transportation mode is carried out to ensure that i
...
CEBU INSTITUTE OF TECHNOLOGY - UNIVERSITYCollege of Engineering and ArchitectureDepartment of Civil Engineering1.INTRODUCTIONThe structural designof thetravelway of any transportation mode is carried out to ensure that it isstructurally sound and can withstand the loads imposed upon it by vehicles of that mode over itsdesign life. The methods presented are based on American Association of State andTransportation Highway Officials (AASHTO) for highway pavements and American RailwaysEngineering and Maintenance-of-Way Association (AREMA) for railroad tracks.2. PAVEMENT DESIGN2.1.ImportancePavements are among the costliest items associated with highway construction and maintenance,and are largely responsible for making the U.S. highway system the most expensive public worksproject undertaken by any society. Because the pavement and associate shoulder structures arethe most expensive items to construct and maintain, it is important for highway engineers to havea basic understanding of pavement design.2.2. Two Basic Functions of a Paved SurfaceIt helps guide drivers by giving them a visual perspective of the horizontal and verticalalignment of the travelled path, thus giving them information relating to the driving task andthe steering control of the vehicleIt supports the load induced by the vehicles by transmitting the weight to the pavement,then to the subgrade at a level that is acceptable and bearable, depending on theengineering properties of the subgrade.2.3.Ideal Road Pavement RequirementThe following are the characteristics of an ideal pavement:Sufficient thickness to distribute the wheel load stresses on the subgrade soil to asafe level.It is structurally sound and can withstand all types of stresses.Vehicles must have an enough coefficient of friction to avoid sliding.Even at high speeds, the smooth surface provides comfort to road users.Produce the least amount of noise possible from moving cars.So that traffic safety is not jeopardized by reduced visibility, a dust-proof surface isused.So that sub-grade soil is properly protected, there is an impervious surface.Long design life with a minimal cost of maintenance.CE331 - HIGHWAY AND RAILROAD ENGINEERING
CEBU INSTITUTE OF TECHNOLOGY - UNIVERSITYCollege of Engineering and ArchitectureDepartment of Civil Engineering3. TYPES OF PAVEMENTSFlexible and rigid pavement are the two types of pavement that are commonly used in roadconstruction. The pavement structure primarily aims to reduce and distribute the surface stressesat an acceptable level at the subgrade.3.1. Flexible PavementThe surface layer of flexible pavements is made of bituminous (or asphalt materials). The loads ofthe vehicle are distributed to the subgrade by grain to grain transfer through the points of contactin the granular structure. The wheel loads on the pavement are dispersed to a wider area, and thestress reduces as the depth increases. With the stress distribution properties, flexible pavementscommonly have multiple layers. As a result, the
[Show More]
