SHOTS - TRANSPORTATION ENGINEERING
💥 Nagpur road plan prepared by assuming radial or star and grid pattern.
💥 The sequence of four stage of survey in a highway alignment is map study, reconnaissance survey, preliminary survey and detailed survey.
💥 The shape of the camber best suited for concrete pavements is straight line.
💥 Skidding-when the path travelled along the road surface is more than the circumferential movement.
💥 Coefficient of friction is less when the road surface is smooth and wet.
💥 Camber in the road is provided for effective drainage.
💥 The desirable length of overtaking zone as per IRC is 5*OSD.
💥 SSD60% steep terrain.
💥 As per IRC the max limit of super elevation in plain terrain is 1in15.
💥 For the design of super elevation for mixed traffic condition the speed is reduced by 25%.
(e)equilibrium=V^2/127R.
(e)max=V^2/225R.
💥 W= Wm+Wps= (nl^2/2R)+(V/9.5R).
💥 In case of hill roads the extra widening is generally provided on fully inner side of road way.
💥 The transition curve is used as per IRC is spiral.
💥 The maximum design gradient for vertical profile is ruling gradient.
💥 The camber of road should be approximately equal to half of the longitudinal gradient.
💥 Cubic parabola is preferred in vertical curves.
💥 0.38(NV^3)1/2 length of valley curve.
💥 Highway facilities are designed for 30th highest hourly volume.
💥 Enoscope is used for measuring the spot speed.
💥 For highway geometric design the speed is 98th percentile speed.
💥 Length of the vehicle affects the extra width and minimum turning radius.
💥 2.44m is the maximum width of the vehicle by IRC.
💥 Desire lines are plotted in origin and destination studies.
💥 Collision diagram is used in accidents.
💥 Traffic volume=traffic density*traffic speed.
💥 Practical capacity is known as design capacity.
💥 On a right angled road intersection with 2 way traffic the total number of conflict points is 24.
💥 The background colour of informatory sign board is yellow.
💥 Level crossing is a warning signal.
💥 Dead slow is regulatory sign.
💥 The most efficient traffic signal system is flexible progressive system.
💥 Centre line markings are used in roadways meant for 2 way traffic.
💥 The entrance and exit curves of a rotary is different radii and different width.
💥 A traffic rotary is justified when the number of intersections is between 4 to 7.
💥 Maximum number of vehicles parked with 90’ angle parking.
💥As per IRC the average level of illumination is 30lux.
💥 The most economical lightning layout is single side lightning.
💥 Abrasion test used for wear, impact test used for toughness.
💥 Los angles testing machine used for abrasion.
💥 In CBR test CBR is calculated for both 2.5mm and 5mm penetration.
💥 30% is the maximum allowable value los angles abrasion value for high quality surface.
💥 The percentage of free carbon in bitumen is less than that in tar.
💥 The ductility value of bitumen for suitability in road construction should not be less than 50cm.
💥 0.6% is the maximum limit of water absorption suitable for road construction.
💥 30/40 representing the hardest grade of bitumen.
💥 Penetration test is used for determining the grade.
💥 Bitumen grade 80/100mm means its penetration value is 8 to 10mm.
💥 RT-5 is the recommended grade of tar grouting purpose.
💥 For rapid curing cutback the oil used is gasoline.
💥 CBR method is recommended by IRC for design of flexible pavement.
💥 Bottom most layer of pavement is sub grade.
💥 Flexible pavement distributes the load through a set of layers.
💥 Group index method is a theoretical method.
💥 Tyre pressure influences the quality of surface course.
💥 Critical load position in a rigid pavement is interior, edge, corner loading.
💥 Tie bars in cement concrete pavements are at longitudinal joints.
💥 The maximum spacing of contraction joints is 4.5m.
💥 The maximum thickness of expansion joint is 25mm.
💥 The function of expansion joint is to allow free expansion.
💥 Most suitable material for highway embankment is granular material.
💥 The most suitable equipment for compacting clayey soil is sheep foot roller.
💥 The binder used in flexible pavement is bitumen.
💥 In highway construction rolling starts from sides and proceed to the centre.
💥 For base course –bitumen bound macadam is used.
💥 The suitable surfacing material for bridge deck slab is mastic asphalt.
💥 Bituminous concrete is the highest quality construction in the group of black top pavements.
💥 The thickness of bitumen carpet varies from 20 to 25mm.
💥 In highway construction on super elevated curves the rolling shall proceed from lower edge towards the upper edge.
💥 Expansion joints provided at an interval of 18m to 21m.
💥 2.5% is the camber for hill road in case of bituminous surfacing.
💥 20mph is the minimum design speed in air pin bends.
💥 Breast wall provided to prevent the slipping.
💥 In hill roads the side drains are provided only on hill side of roadway.
💥 For sandy soil the most common method is soil stabilisation method.
💥 Bituminous or asphalt concrete construction the proportions are determined from laboratory.
💥 In group index method the thickness is determined by daily volume of commercial vehicles.
💥 In a bituminous pavement the alligator cracking is mainly due to fatigue arising from repeated stress applications.
💥 The main function of prime coat is provide bond between the existing base and surfacing of new construction.
💥 Benkle beam test is used for overlay design, ring and ball test used for softening point test, penetration test used for gradation, marshall test used for design of bituminous concrete mix.
💥 Expansion and contraction joints should provided at 50m and 10m.
💥 Reflection cracking is observed in bituminous overlay over cement concrete.
💥 Low bitumen content causes ravelling in bituminous pavement.
💥 For carrying out bituminous patch work during the rainy season the most suitable binder is bituminous emulsion.
💥 ISD =2SSD as per IRC.
💥 As per IRC guidelines for designing the flexible pavement the load parameter is cumulative standard axles in msa.
💥 Rapid curing cutback bitumen is produced by blending petrol.