4 10 points Your firm has been contracted to design a road t

4. (10 points) Your firm has been contracted to design a road that will provide occasional access to a vehicle with a maximum single axle load of 22,600 lbf (11,300 lbf per wheel) with 100 psi tire pressure. Site investigations indicate the existing subgrade is a clayey soil that will have a modulus as low as 3000 psi during the wet part of the year. Under these conditions, laboratory tests have determined that the subgrade cannot tolerate vertical stresses greater than 10 psi without incurring high permanent deformation (rutting). Using two layer theory, you are to consider one of two possible designs: Crushed rock (Er= 40,000 psi) with a thin bituminous seal coat surface to make the pavement impermeable. The cost of the crushed rock is $10.00 per ton (unit weight = 120 1b/ftº) and the cost of the seal coat may be considered negligible for your analysis. Asphalt concrete (Eac= 200,000 psi) at a cost of $50.00 per ton (unit weight = 145 1b/ft). Determine which of these two options would be the most economical.

Solution

primary alternative be extra economical. compressed amaze is an reasonably priced fabric. Cheaply available. An tarmac driveway determination need additional usual preservation. It require re- seal each 3 years or so. near to the ground end sealants price approximately $5 for a five gallon pail and wrap approximately 40o four-sided figure foot of tarmac. far above the ground end sealants be able to cost upwards of $20 per pail. But a break on a compressed astound asphalt road will price less intended for the mend. More fabric and equipments and additional manpower is necessary for tarmac asphalt road. tarmac infrastructure cannot last for extended. Asphalt driveways require hard basics ready by expert. tarmac will shrink plus expand by means of hotness change and leads to high maintenance cost. Initial cost $2 to $5 per square foot of driveway. Overall we come to know crushed astound is additional inexpensive