One liners - Transportation Engineering for GATE, PSUs - Part 7

Hello there,

How have you been? Here is another round of one liners for your preparation for the GATE and PSUs examinations.

• Bottom-most layer of a pavement is called Sub-grade.

• Flexible pavement distribute the wheel load through a set of layers to the sub-grade.

• The number of repetitions, which the pavement thickness designed for a given wheel load should be able to support during the life of a pavement is 1000000.

• Group Index Method of design of flexible pavement is an empirical method based on physical properties of sub-grade soil.

• Minimum and maximum values of a Group Index can be 0 and 20 respectively.

• If the Group Index value of sub-grade is between 5 to 7, then sub-grade is treated as poor.

• Tyre pressure influences the quality of the surface course.

• Rigidity factor for a tyre pressure greater than 7 kg/cm2 is less than 1.

• In a dual wheel assembly if P is equal to each wheel load, S is centre to centre distance of dual wheels and d is the distance between walls of wheels, then total stress due to the dual wheels at any depth greater than S is equivalent to a single wheel load of magnitude 2P.

• Main drawback of CBR method is that it gives the total thickness which remains same irrespective of the quality of materials used in the component layers.

• Critical load positions in a rigid pavement design is taken as interior, edge and corner loading.

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