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IENG 217 Cost Estimating for Engineers Project Estimating
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Hoover Dam U.S. Reclamation Service opened debate 1926 Six State Colorado River Act, 1928 Plans released 1931, RFP Bureau completed its estimates 3 bids, 2 disqualified Winning bid by 6 companies with bid price at $48,890,955 Winning bid $24,000 above Bureau estimates
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Project Methods Power Law and sizing CERs Cost estimating relationships Factor
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Power Law and Sizing In general, costs do not rise in strict proportion to size, and it is this principle that is the basis for the CER
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Power Law and Sizing
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Ten years ago BHPL built a 100 MW coal generation plant for $100 million. BHPL is considering a 150 MW plant of the same general design. The value of m is 0.6. The price index 10 years ago was 180 and is now 194. A substation and distribution line, separate from the design, is $23 million. Estimate the cost for the project under consideration.
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Class Problem
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CER
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Factor Method Uses a ratio or percentage approach; useful for plant and industrial construction applications
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Factor Method Basic Item Cost Factor
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Adjustment for Inflation
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Example; Plant Project
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4.1 1.7 1.1
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Example; Plant Project
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Other Project Methods Expected Value Range Percentile Simulation
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Expected Value Suppose we have the following cash flow diagram. NPW = -10,000 + A(P/A, 15, 5) 1 2 3 4 5 A A A A A 10,000 MARR = 15%
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Expected Value Now suppose that the annual return A is a random variable governed by the discrete distribution: A p p p 200016 3 23 4 16,/,/,/
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Expected Value A p p p 200016 3 23 4 16,/,/,/ For A = 2,000, we have NPW = -10,000 + 2,000(P/A, 15, 5) = -3,296
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Expected Value A p p p 200016 3 23 4 16,/,/,/ For A = 3,000, we have NPW = -10,000 + 3,000(P/A, 15, 5) = 56
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Expected Value A p p p 200016 3 23 4 16,/,/,/ For A = 4,000, we have NPW = -10,000 + 4,000(P/A, 15, 5) = 3,409
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Expected Value There is a one-for-one mapping for each value of A, a random variable, to each value of NPW, also a random variable. A 2,000 3,000 4,000 p(A) 1/6 2/3 1/6 NPW -3,296 56 3,409 p( NPW ) 1/6 2/3 1/6
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Expected Value E[Return] = (1/6)-3,296 + (2/3)56 + (1/6)3,409 = $56 A 2,000 3,000 4,000 p(A) 1/6 2/3 1/6 NPW -3,296 56 3,409 p( NPW ) 1/6 2/3 1/6
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