Marks 1
Various stresses in jointed plain concrete pavement with slab size of 3.5 m × 4.5 m are denoted as follows:
Wheel load stress at interior = $S_{wl}^i$
Wheel load stress at edge = $S_{wl}^e$
Wheel load stress at corner = $S_{wl}^c$
Warping stress at interior = $S_t^i$
Warping stress at edge = $S_t^e$
Warping stress at corner = $S_t^c$
Frictional stress between slab and supporting layer = $S_f$
The critical stress combination in the concrete slab during a summer midnight is
A car is travelling at a speed of 60 km/hr on a section of a National Highway having a downward gradient of 2%. The driver of the car suddenly observes a stopped vehicle on the car path at a distance 130 m ahead, and applies brake. If the brake efficiency is 60%, coefficient of friction is 0.7, driver’s reaction time is 2.5 s, and acceleration due to gravity is $9.81 \text{ m/s}^2$, the distance (in meters) required by the driver to bring the car to a safe stop lies in the range
Marks 2
The consolidated data of a spot speed study for a certain stretch of a highway is given in the table.
| Speed range (kmph) | Number of observations |
|---|---|
| 0 - 10 | 7 |
| 10 - 20 | 31 |
| 20 - 30 | 76 |
| 30 - 40 | 129 |
| 40 - 50 | 104 |
| 50 - 60 | 78 |
| 60 - 70 | 29 |
| 70 - 80 | 24 |
| 80 - 90 | 13 |
| 90 - 100 | 9 |
The "upper speed limit" (in kmph) for the traffic sign is
The following data is obtained from an axle load survey at a site:
Average rear axle load = 12000 kg
Number of commercial vehicles = 800 per day
The pavement at this site would be reconstructed over a period of 5 years from the date of the survey. The design life of the reconstructed pavement is 15 years. Use the standard axle load as 8160 kg and the annual average vehicle growth rate is 4.0%. Assume that Equivalent Wheel Load Factor (EWLF) and Vehicle Damage Factor (VDF) are equal.
The cumulative standard axle (in msa) for the pavement design is ____________ (rounded off to 2 decimal places).