The structural engineering design section within the enginee

The structural engineering design section within the engineering department of a regional electrical utility corporation has developed several standard designs for a group of similar transmission line towers. The detailed design for each tower is based on one of the standard designs. A transmission line project involving 48 towers has been approved. The estimated number of engineering hours needed to accomplish the first detailed tower design is 122. Assuming a 97% learning curve. a. What is your estimate of the number of engineering hours needed to design the sixth tower and to design the last tower in the project? b. What is your estimate of the cumulative average hours required for the first four designs? a. The number of engineering hours needed to design the sixth tower is hours. (Round to one decimal place.)

Solution

Tn=T1(N^b)

T1=122, b=log0.97/log2 , N=6

Tn=122(6^-0.04)=113.56 hours

for 48th tower

T48=122(48^(-0.04))=104.5 hours

CUmulative time

T1+T2+T3+T4=122(1)+122(2^(-0.4))+122(3^(-0.04))+122(4^(-0.04))=446.63 hours