Civil PE Exam - Construction - Benefit to Cost Ratio of a Bridge

[@ccbanka]

For (P/F,15,7%) I got 0.3624 (appears the 0.5083 value used in the video is for 10 years, not 15). Also, for (P/F,7%,25) I got 0.1842 (not 0.6227). The B/C ratio I calculated is 1.15. Thank you very much for these videos. They have been outstanding and a great help.

[@CivilEngAcademy]

ccbanka Thank you for catching this! I don't know what I was looking up..I think it was late night! I have corrected the video with some comments so I hope it helps others that check it out.

[@serpico3312]

Civil Engineering Academy I get 1.14 which is not much different than ccbanka. We all make mistakes; aside from that, the videos are great! Keep making the videos.

[@tiancaidexiongxiong]

Here is what I got: (7*9.1079+10*7.0236*0.3624+15*0.1842)/80=1.15

[@alimoh1984]

Thanks for adding the corrections on the video as caption. thanks for your time

[@cocoon757]

why annual cost of repairing the bridge does not count as cost (Denominator)?

[@AbidAli-bv2gl]

Sir, you are doing great, Keep going on.You will be the best teacher for PE exam

[@cdf4013]

Can I put the increase of salvage value as my benefit and use initial cost (80k) as my total cost for calculating B/C? By the way, thanks for your great video.

[@supermanny73]

Where can I find the corrected video? Thanks.

[@supermanny73]

Sorry, I just saw the notes and corrections. When I first saw this video, it was on my cell phone and the notes were not appearing. Excellent video...keep up the great work!!

[@adamalday01]

The book recommends superposition for stepped cash flows. When I try this method I don't come up with the correct present value.Any idea why?

[@CivilEngAcademy]

Your calculation should be close to the solved solution. Maybe you used incorrect value from the table. I tried to use superposition and got close answer in the video. Using superposition: Present value of Benefit = 10*(P|A,25,7%) - 3*(P|A,15,7%) = 10*11.6536 - 3*9.1079 = 89.2123 Your solution: Present value of Benefit = 7*(P|A,15,7%) + 10*(P|A,10,7%)*(P|F,15,7%) = 7*9.1079 + 10*7.0236*0.3624 63.755 + 25.45 89.205

[@adamalday01]

Thank you for the response