Tuesday, January 7, 2014

One liners - Transportation Engineering for GATE, PSUs - Part 10

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

  • Ratio of width of the car parking area required at kerb for 30 degree parking relative to 60 degree parking is approximately 0.5
  • Load carrying capacity of rigid pavements depends more on the properties of concrete than strength of sub-grade.
  • Compared to flexible pavements, rigid pavements are more affected by temperature variations.
  • Collision diagrams are used to study accident pattern and determine remedial measures.
  • Emergency escape ramp is provided in down grades of a highway.
  • Plasticity index of the fraction passing 425 micron IS Sieve in case of sub-base or base course would be less than 6.
  • If the CBR value obtained at 5 mm penetration is higher than that at 2.5 mm, then the test is repeated for checking; and if the check test reveals a similar trend, then the CBR value is to be reported as higher value obtained at 5 mm penetration.
  • Road construction/design in chronological sequence : Tresaguet, Telford, Macadam & C.B.R.
  • The general requirement in constructing a reinforced concrete road is to place a single layer of reinforcement near the top of the slab.
  • It is a common practice to design a highway to accommodate the traffic volume corresponding to 30th hour.
  • The amount of mechanical energy imposed on the aggregate during the aggregate impact test is of the order of (15*14*38 kg-cm) 7980 kg-cm.
  • For wet and cold climates emulsions are recommended to be used as binders.
  • With reference to Marshall mix design criteria for highways, Stability value = 340 min.; Flow value = 8-16 & % air voids = 3-5.
  • For the design of valley vertical curve, the design criteria used are rider comfort, headlight sight distance and drainage.
  • Bird baths may be formed as the deformations which may be caused by localized or variable sub-grade failure.
  • Pot holes A steep sided, bow-shaped cavity caused by the loss of surfacing as well as base course erosion.
  • Ravelling is the removal of larger surface aggregates leaving craters.
  • Subsidence is abrupt lowering of the road surface due to poor drainage.
  • For carrying out bituminous patch work during the rainy season, the most suitable binder is bituminous emulsion.
  • The characteristic rebound deflection on a pavement, using Benkelman beam study is used by IRC to suggest the equivalent overlay design thickness.

Do you have better resource to crack the competitive examinations like GATE and PSUs?
Please share here.

Sand Cone Method to Determine Density - A solved Example

Hi, This problem deals with the Sand Cone Test used to determine the density of the compacted soil. Problem: A sand cone density test w...