Answer Happy

A new highway is to be constructed. Design A calls for a concrete pavement costing $90 per foot with a 20-year life; four paved ditches costing $3 per foot each; and four box culverts every mile, each costing $10,000 and having a 20-year life. Annual maintenance will cost $1,800 per mile; the culverts must be cleaned every five years at a cost of $300 each per mile. Design B calls for a bituminous pavement costing $55 per foot with a 10-year life; two sodded ditches costing $1.50 per foot each; and four pipe culverts every mile, each costing $2,150 and having a 10-year life. The replacement culverts will cost $2,450 each. Annual maintenance will cost $2,800 per mile; the culverts must be cleaned yearly at a cost of $230 each per mile; and the annual ditch maintenance will cost $1.55 per foot per ditch. Compare the two designs on the basis of equivalent worth per mile for a 20-year period. Find the most economical design on the basis of AW and PW if the MARR is 8% per year.