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If the load, warping and frictional stresses in a cement concrete slab are 210 N/mm2 , 90 N/mm2 and 10N/mm2 respectively. The critical combination of stresses during summer mid-day is
For Summer mid-day ,
S = S + Sw - Sf = 210 + 90 - 10 = 290 N/mm2
The superelevation needed for a vehicle travelling at a speed of 60 km/h on a curve of radius 128 m a surface with a coefficient of friction of 0.15 is
The maximum super elevation to be provided on a road curve is 1 in 15. If the rate of change of super elevation is specified as 1 in 120 and the road width is 10m, then the minimum length of the transition curve on the either end will be
Provide an assumption in the question Assuming super-elevation introduction with respect to inner edge.
Since only superelevation (e = 1/15), width of road(W=10m) and rate of super-elevation (N=120) is provided. Therefore, using one of the formula to determine the length of transition curve (Ls) when super-elevation is introduced with respect to inner edge.
L_s=ⅇNW = 1/15×120×10 = 80 m
In highway geometric design, once the cumulative speed distribution is drawn, the design adequacy is checked at
In cumulative speed distribution following values must be designed for:
- 98th percentile speed: check for design adequacy
- 85th percentile speed: Upper speed limit
- 15th percentile speed: Lower speed limit
Penetration to know the grade of bitumen is measured in
Penetration value is the vertical distance traversed by the point of a standard needle into the bituminous material under specific conditions of load, time and temperature.
The distance is measured in one tenths of a millimetre.
It mean a penetration value of 80 means the actual penetration is 8mm.
For total reaction time of 2.5 s, coefficient of friction 0.35, and design speed of 80 km/h, what is the stopping sight distance on a highway?
What is the superelevation for a horizontal highway curve of radius 500 m and speed 100 km/h in mixed traffic condition?
Given data;
V = 100 Kmph
R = 500 meter
For mixed traffic conditions, Super elevation is given by formula for maximum super elevation:
e = V2/ (225 x R)
= 1002/ (225 x 500)
= 0.089 m per meter of carriage way OR
= 0.089 x 100
= 8.9 %
The length of a transition curve for a circulation curve of radius 300 m and for a design speed of 15 m/s, when the rate of change of centrifugal acceleration is 0.3 m/s3 is
Bitumen grade 80/100 indicates that under the standard test conditions, penetration value of bitumen would vary from
Modulus of subgrade reaction using 30 cm diameter plate is obtained as 200 N/cm3. The value of the same (in N/cm3) using the standard plate will be __________ N/cm3.
A rest vertical curve joints two gradients of +3% and –2% for a design speed of 80 km/h and the corresponding stopping sight distance of 120 m. The height of driver’s eye and the object above the road surface are 1.20 m and 0.15 m, respectively. The curve length (which is less than stopping sight distance) to be provided is _________ m.
The design speed for a two-lane road is 80 km/h. When a design vehicle with a wheel base of 6.6 m is negotiating a horizontal curve on that road, the off-tracking is measured as 0.096 m, the required widening of carriageway of the two-lane road on the curve is approximately
It is proposed to widen and strengthen an existing two lane NH section as a divided highway. The existing traffic in one direction is 2500 commercial vehicles (CV) per day. The construction will take 1 yr.
The design CBR of soil subgrade is found to be 5% Given: Traffic growth rate for CV = 8% Vehicle damage factor = 3.5 (standard axles per CV) Design life = 10 yr, Traffic distribution factor = 0.75
The cumulative standard axles 9 (msa) computed are
To compute the cumulative standard axles (msa) for the proposed highway, you need to first calculate the design traffic volume for the highway. The design traffic volume is the expected traffic volume on the highway over its design life, which in this case is 10 years. The design traffic volume can be calculated using the following formula:
Design traffic volume = (existing traffic volume + (traffic growth rate * existing traffic volume * design life)) * traffic distribution factor
Plugging in the given values, we get: Design traffic volume = (2500 + (8% * 2500 * 10)) * 0.75 = (2500 + 2000) * 0.75 = 4500 * 0.75 = 3375
Next, we need to calculate the number of standard axles that the highway will experience over its design life. The number of standard axles can be calculated using the following formula:
Number of standard axles = design traffic volume * vehicle damage factor
Plugging in the values, we get: Number of standard axles = 3375 * 3.5 = 11737.5
Finally, we can calculate the cumulative standard axles (msa) for the highway using the following formula:
Cumulative standard axles (msa) = number of standard axles * design CBR
Plugging in the values, we get: Cumulative standard axles (msa) = 11737.5 * 5% = 586.875
Rounding this value to the nearest whole number gives us 587 cumulative standard axles (msa).
Therefore, the correct answer is 1, "65."
The width of the expansion joint is 20 m in a cement concrete pavement. The laying temperature is 20° C and the maximum slab temperature in summer is 60° C. The coefficient of thermal expansion of concrete is and the joint filler compresses upto 50% of the thickness. The spacing between expansion joints should be
A vehicle moving at 60 km/h on an ascending gradient of a highway has to come to stop position to avoid collision with a stationary object. The ratio of lag to brake distance is 6:5. Considering total reaction time of the driver as 2.5 s and the coefficient of longitudinal fraction as 0.36, the value of ascending gradient (%) is
27 docs|296 tests
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27 docs|296 tests
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