Assume steel alloy is only way of having
uninterrupted service.
P = $191,524 is thus minimum PV of having
50 years of uninterrupted service.
P = R(USPW)
Pab = $191,524 = R (USPW i=0.06, n=50)
= $191,524
=R(15.762)
$191,524/15.762 =$12,150 = annual value of having a bridge, so
monthly
value of having
bridge = $12,150/12 = $1013
P = $1013 (SPPW i=0.06, n=25)
= $1013 (0.233) = $236
Hence, the negative effect of being
without a bridge for 1 month 25 years from now would have present value of at least
$236