CHAPTER 8 COST ESTIMATION 8.1 Cost Estimation for Rough Planning Stage When you are going to make a trial calculation of construction cost in Rough Planning Stage, it can be calculated by the method shown in Table8.1.2. However, before calculating, it is necessary to carry out an easy field survey, and decide the item mentioned to Table8.1.1. Table8.1.1 Items to make a trial calculation of construction cost Description Item Plan Maximum Out Put (kw) Turbine Discharge (m 3 /s) Effective Head (m) Intake Facilities Height of Dam (m) Length of Dam (m) Headrace Length of Headrace (m) Penstock Diameter of Penstock (m) Distribution Number of Households (kk) Distance to the furthest house from P.S In addition, since indirect costs, such as tax, contractor fee, design cost, and supervisor fee, are contained in the cost of construction calculated by Fig 8.1.2, when a part of these indirect costs can be omitted, examination is required separately. - 8-1 -
Table8.1.2 Method to make a trial calculation of construction cost in Rough Planning Stage No. Description Formulation Remarks (1) PREPARATORY WORKS {(2)+(3)+(4)+(5)} 0.1 Transportation, Clearing, Temporally Works (2) CIVIL WORKS 1~7 1 Intake Facilities Gabion Dam 210,000 (H L) H : Height of Dam(m) L : Length of Dam(m) 2 Settling Basin Stone Masonry Dam 785,000 (H L)+850,000 Concrete Dam 1,650,000 (H L) Long or Mid-Penstock type 60,300,000 Q 0.504 H : Height of Dam(m) L : Length of Dam(m) H : Height of Dam(m) L : Length of Dam(m) (Rp) Q : Turbine Discharge(m 3 /s) (Back to System Layout : Page4-2) Short Penstock type 54,200,000 Q 0.794 Q : Turbine Discharge(m 3 /s) (Back to System Layout : Page4-1) 3 Headrace 435,000 Q 0.18 L Q : Turbine Discharge(m 3 /s) L : Length of Headrace(m) 4 Head Tank 47,600,000 Q 0.5 Q : Turbine Discharge(m 3 /s) 5 Penstock Civil Works 775,000 φ 0.571 L φ : Daiameter of Penstock (m) L : Length of Penstock (m) Pestock L : Length of Penstock (m) 15,000 (Unit waight) L 6 Power House Base 4,890,000 P 0.456 P : Maximum Output(kW) (Include Tail race) 7 Power House Building 2,460,000 P+20,350,000 P : Maximum Output(kW) (3) ELECTROMECHANICAL WORKS 75,710,000 (P/ He) 0.56 Closs flow Turbine T-13 P : Maximum Output(kW) He : Effective Head(m) (4) DISTRIBUTION WORKS 14,300 X 0.5541 X : Number of Household Distance 2 (5) CONSUMER CONNECTION 428,000X+31,900,000 X : Number of Household (6) OTHERS {(2)+(3)+(4)+(5)} 0.05 TOTAL (1)+(2)+(3)+(4)+(5)+(6) - 8-2 -
100,000,000 90,000,000 Concrete Dam 80,000,000 Cost (Rp) 70,000,000 60,000,000 50,000,000 40,000,000 Cost(Rp) = 1,650,000*(H L) Stone Masonry Cost(Rp) = 785,000*(H L) + 850,000 30,000,000 20,000,000 10,000,000 y = 210,000*(H L) Gabion Dam 0 0 10 20 30 40 50 60 70 80 H L Fig8.1.1 Cost of Intake facilities Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-3 -
80,000,000 70,000,000 60,000,000 50,000,000 Long or Mid-length Penstock type Cost(Rp) =60,300,000*Q 0.504 Cost (Rp) 40,000,000 30,000,000 20,000,000 Short Penstock type Cost(Rp) = 54,200,000*Q 0.794 10,000,000 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Q (m 3 /s) Fig8.1.2 Cost of Settling Basin Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-4 -
500,000 Unit Cost(Rp/m) = 435,000*Q 0.18 450,000 400,000 Unit Cost (Rp/m) 350,000 300,000 250,000 200,000 0 0.2 0.4 0.6 0.8 1 1.2 Q (m 3 /s) Fig8.1.3 Unit Cost of Headrace Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-5 -
70,000,000 Cost(Rp) = 47,600,000*Q 0.5 60,000,000 50,000,000 40,000,000 Cost (Rp) 30,000,000 20,000,000 10,000,000 0 0 0.2 0.4 0.6 0.8 1 1.2 Q (m 3 /s) Fig8.1.4 Cost of Head tank Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-6 -
1,200,000 Cost(Rp) = 775,000φ 0.571 1,000,000 800,000 Cost (Rp) 600,000 400,000 200,000 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Daiameter of Penstock φ(m) Fig8.1.5 Cost of Penstock (Civil Works) Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-7 -
100 90 80 t=3mm y = 0.07417 φ + 0.00133 t=4mm y = 0.0989φ - 0.0021 t=5mm y = 0.1236φ + 0.0012 t=5mm 70 Unit vilume waigth (kg/m) 60 50 40 t=3mm t=4mm 30 20 10 0 100 200 300 400 500 600 700 800 Daiameter of Penstock φ(mm) Fig8.1.6 Unit volume waight of Penstock Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-8 -
40,000,000 Cost(Rp) = 4,890,000*P 0.456 35,000,000 30,000,000 25,000,000 Cost (Rp) 20,000,000 15,000,000 10,000,000 5,000,000 0 0 10 20 30 40 50 60 70 80 P (kw) Fig8.1.7 Cost of Power house Base (Inc. Tail race) Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-9 -
250,000,000 Cost(Rp) = 2,460,000P + 20,350,000 200,000,000 150,000,000 Cost (Rp) 100,000,000 50,000,000 0 0 10 20 30 40 50 60 70 P (kw) Fig8.1.8 Cost of Power house builiding Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-10 -
400,000,000 Cost(Rp) = 75,710,000 (P/ He) 0.56 350,000,000 300,000,000 250,000,000 Cost (Rp) 200,000,000 150,000,000 100,000,000 50,000,000 0 0 2 4 6 8 10 12 14 P/ He Fig8.1.9 Cost of Electromechanical Works Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-11 -
800,000,000 Cost(Rp) = 14300x 0.5541 700,000,000 600,000,000 500,000,000 Cost (Rp) 400,000,000 300,000,000 200,000,000 100,000,000 0 0 50,000,000 100,000,000 150,000,000 200,000,000 250,000,000 x = (Number of Household) * (Distance) ^ 2 Fig8.1.10 Cost of Distribution Works Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-12 -
350,000,000 Cost (Rp) = 428000 x + 31900000 300,000,000 250,000,000 200,000,000 Cost (Rp) 150,000,000 100,000,000 50,000,000 0 0 100 200 300 400 500 600 700 Number of Household Fig8.1.11 Cost of Consumer Connection Notes: For a trial calculation of construction cost in Rough Planning Stage - 8-13 -
8.2 Cost Estimation for Detail Design Stage Construction cost consists of items as shown in Table8.2.1. Table8.2.1 Construction Cost No. Item Cost Direct cost of construction 1 PREPARATORY WORKS Addition item 2 CIVIL WORKS Addition item 3 ELECTRO-MECHANICAL WORKS Addition item 4 DISTRIBUTION WORKS Addition item 5 CONSUMER CONNECTION Addition item SUB TOTAL(A) Indirect cost 1 DESIGN FEE 5~10% of SUB TOTAL(A) 2 SUPERVISOR FEE 5~10% of SUB TOTAL(A) 3 MANAGEMENT FEE 5~10% of SUB TOTAL(A) 4 TAX 12.5% of SUB TOTAL(A) SUB TOTAL(B) TOTAL 8.2.1 Items Typical items of a direct cost are shown below. (1) Preparatory works Preparatory works consist of item as follows. - Location setting out - Felling and measurement - Equipment & materials mobilization (2) Civil works Civil works consist of item as follows. - Intake facilities - Settling basin - Headrace - Head tank - 8-14 -
- Spillway - Penstock and foundation - Powerhouse base - Tailrace - Power house building - Finishing (3) Electro-mechanical works Electro-mechanical works consist of item as follows. - Turbine - Controller - Dummy load - Generator - Accessories, spare parts and tools - Set up and installation - Transportation and packing - Testing - Pre commissioning trial run (4) Distribution works Distribution works consist of item as follows. - Transmission pole - Cable - Transformer - Accessories (5) Consumer connection - Cable - Switch - Accessories - 8-15 -
8.2.2 Quantity In order to calculate direct cost of construction, it is necessary to calculate the quantity for every work or material based on design. For example, in case of headrace of masonry, quantity will be calculated for excavation, foundation rubble stone, stone masonry, backfill, and plaster like Fig 8.2.1. Excavation Foundation rubble stone Plaster Backfill Stone masonry Fig 8.2.1 The example of works which should be calculated(headrace) With a natural thing, these items change according to a kind and the quality of structure. For example, in Intake, the item that should calculate will be changed according to type of dam like Table 8.2.2. And in Headrace, the item which should calculate will be changed according to the quality of the material of Headrace like Table 8.2.3. Table 8.2.2 Quantity of dam Gabion dam Masonry dam Concrete dam - Excavation (m 3 ) - Excavation (m 3 ) - Excavation (m 3 ) - Backfill (m 3 ) - Backfill (m 3 ) - Backfill (m 3 ) - Gabion (m 3 ) - Foundation Rubble - Sand filling (m 3 ) Stone (m 3 ) - Concrete (m 3 ) - Stone masonry (m 3 ) - Plaster (m 2 ) - Plaster (m 2 ) - Stoplog (m 2 ) - Stoplog (m 2 ) - Gabion (m 3 ) - Gabion (m 3 ) - 8-16 -
Table8.2.3 Quantity of headrace Simple earth channel Masonry channel Concrete channel - Excavation (m 3 ) - Excavation (m 3 ) - Excavation (m 3 ) - Backfill (m 3 ) - Backfill (m 3 ) - Foundation Rubble - Sand filling (m 3 ) Stone (m 3 ) - Concrete (m 3 ) - Stone masonry (m 3 ) - Plaster (m 2 ) - Plaster (m 2 ) This is the same for other structures too, and care is taken not to omit ay items that should be added up based on drawings.(ref 8.1 Breakdown of Construction Cost of Pilot Project) 8.2.3 Unit Cost Table 8.2.4 shows standard unit cost of civil work of PU. Unit Price of Table 8.2.4 is price of Tana-Toraja. Since unit cost changes according to various situations of each area, it is desirable to perform unit cost setup enough in consideration of the local characteristics. - 8-17 -
Table8.2.4 Unit cost of PU (Toraja) Koef. Unit Unit Price Unit Cost Remark (Rp) (Rp) Excavation(m 3 ) 22,500 unskill labour 0.625 man 15,000 9,375 foreman 0.062 man 17,500 1,085 tools 1.000 ls 12,000 12,000 Total 22,460 Backfill (m 3 ) 15,200 unskill labour 0.192 man 15,000 2,880 foreman 0.019 man 17,500 333 tools 1.000 ls 12,000 12,000 Total 15,213 Sand Filling (m 3 ) 50,400 sand 1.200 m 3 40,000 48,000 unskill labour 0.150 man 15,000 2,250 foreman 0.010 man 17,500 175 Total 50,425 Fondation Rubble Stone (m 3 ) 108,000 stone 1.200 m 3 50,000 60,000 sand 0.400 m 3 40,000 16,000 unskill labour 1.125 man 15,000 16,875 skill labour 0.563 man 25,000 14,075 foreman 0.056 man 17,500 980 Total 107,930 Stone Masonry 1:2 (m 3 ) 234,000 stone 1.200 m 3 50,000 60,000 PC 3.520 zak 26,500 93,280 sand 0.380 m 3 40,000 15,200 unskill labour 2.250 man 15,000 33,750 skill labour 1.125 man 25,000 28,125 chief labor 0.113 man 30,000 3,390 foreman 0.017 man 17,500 298 Total 234,043 Stone Masonry 1:3 (m 3 ) 217,000 stone 1.200 m 3 50,000 60,000 PC 2.840 zak 26,500 75,260 sand 0.400 m 3 40,000 16,000 unskill labour 2.250 man 15,000 33,750 skill labour 1.125 man 25,000 28,125 chief labor 0.113 man 30,000 3,390 foreman 0.017 man 17,500 298 Total 216,823 Stone Masonry 1:4 (m 3 ) 209,000 stone 1.200 m 3 50,000 60,000 PC 2.500 zak 26,500 66,250 sand 0.420 m 3 40,000 16,800 unskill labour 2.250 man 15,000 33,750 skill labour 1.125 man 25,000 28,125 chief labor 0.113 man 30,000 3,390 foreman 0.017 man 17,500 298 Total 208,613-8-18 -
Koef. Unit Unit Price Unit Cost Remark (Rp) (Rp) Surface Finish (m 2 ) 19,100 PC 0.237 zak 26,500 6,281 sand 0.019 m 3 40,000 760 meduam skill labour 0.286 man 20,000 5,720 skill labour 0.214 man 25,000 5,350 chief labor 0.021 man 30,000 630 foreman 0.020 man 17,500 350 Total 19,091 Gabion (m 3 ) 96,600 stone 1.200 m 3 50,000 60,000 wire cage 3.500 kg 7,000 24,500 unskill labour 0.450 man 15,000 6,750 skill labour 0.200 man 25,000 5,000 foreman 0.020 man 17,500 350 Total 96,600 Stoplogs (unit) 281,000 wood 0.048 m 3 4,150,000 199,200 carpenter 1.000 man 25,000 25,000 labour 2.000 man 15,000 30,000 foreman 0.100 man 17,500 1,750 tools 1.000 ls 25,000 25,000 Total 280,950 Working floor (m 2 ) 261,000 PC 3.956 zak 26,500 104,834 sand for concrete 0.550 m 3 50,000 27,500 split/gravel 0.930 m 3 75,000 69,750 tools 1.000 ls 15,000 15,000 labour 2.000 man 15,000 30,000 skill labour 0.500 man 25,000 12,500 chief labor 0.050 man 30,000 1,500 foreman 0.010 man 17,500 175 Total 261,259 Rainforce Concrete K225(m 3 ) 2,211,000 PC 7.896 zak 26,500 209,244 split/gravel 0.810 m 3 75,000 60,750 sand for concrete 0.490 m 3 50,000 24,500 labour 3.000 man 15,000 45,000 skill labour 0.500 man 25,000 12,500 chief labor 0.050 man 30,000 1,500 foreman 0.110 man 17,500 1,925 con.+form tools 1.000 ls 75,000 75,000 steel bar concrete 175.0 kg 7,000 1,225,000 wire 2.000 kg 9,000 18,000 labour for steel concrete 6.750 man 25,000 168,750 chief for steel concrete 2.250 man 30,000 67,500 unskill labour 8.750 man 15,000 131,250 con.+form nail 4.000 kg 7,500 30,000 carpenter 5.000 man 25,000 125,000 chief of carpenter 0.500 man 30,000 15,000 Total 2,210,919-8-19 -
[Ref. 8-1 Cross-sectional method to calculate quantity] It is convenient to use the cross-sectional method when calculating complicated quantities such a headrace. When you want to calculate the quantity of excavation of headrace as shown in the following figure, first, you draw a sectional view for every changing point of cross-sectional form, and the excavation area for every section is calculated using planimeter, etc. - 8-20 -
Next, you can make the next table from the relation between the area of each section, and distance. Section name Excavation Area Average Area Distance Volume 1 2 3 2 3 A - A B - B C - C D - D E - E 1.31 m 2 1.38m 2 1.37m 2 1.375m 2 1.245m 2 1.12m 2 1.090m 2 1.06m 2 1.345m 2 2.00m 3.00m 3.00m 2.00m 2.690m 3 4.125m 3 3.735m 3 2.180m 3 Total 12.73m 3 This cross-sectional method is applicable not only to excavation area but also to calculation quantities of backfill or masonry. - 8-21 -
[Ref. 8-2 The example of bill of quantity] No Description Unit Quantity Unit Price Amount Total Price Rp Rp Rp I PREPARATORY WORKS II CIVIL WORKS 1 Intake Facilities include setling basin a. Excavation m 3 b. Backfill m 3 c. Foundation rubble stone m 3 d. Stone Masonry 1 : 2 m 3 e. Plaster m 2 f. Gabions m 3 g. Stoplogs (80 w x 100 h ) cm 2 unit h. Flushing Gate (60 w x 210 h ) cm 2 unit i. Screen m 2 sub total 2Headrace a. Excavation m 3 b. Backfill m 3 c. Foundation rubble stone m 3 d. Stone Masonry 1 : 4 m 3 e. Plaster m 2 f. Stoplogs (80w x 100h) cm2 unit sub total 3 Head Tank a. Excavation m 3 b. Backfill m 3 c. Foundation rubble stone m 3 d. Stone Masonry 1 : 3 m 3 e. Plaster m 2 f. Gate (60 w x 200 h ) cm 2 unit g. Screen m 2 sub total 4 Spillway Channel a. Excavation m 3 b. Backfill m 3 c. Foundation rubble stone m 3 d. Stone Masonry 1 : 4 m 3 e. Plaster m 2 sub total 5 Penstock and Foundation a. Excavation m 3 b. Reinforced Concrete m 3 c. Working floor m 3 d. Sand filling m 3 e. Plaster m 2 f. Penstock set work m 1 g. Welded steel m 1 h. Butterfly valve unit I. Reducer pipe unit j. Clamp penstock pcs k. Bend degree angle pcs l. Anchor bolt pcs sub total - 8-22 -
No Description Unit Quantity Unit Price Amount Total Price Rp Rp Rp 6 Power House Base + Tail Race a. Excavation m 3 b. Backfill m 3 c. Sand filling m 3 d. Working floor m 3 e. Reinforce Concrete m 3 f. Foundation rubble stone m 3 g. Stone Masonry 1 : 4 m 3 h. Surface finish m 2 sub total 7 Power House a. Building m 2 sub total 8 Finishing a. Penstock painting m 1 b. Building Painting ls c. Service Walkway m 1 sub total III MECHANICAL & ELECTRICAL 1 Crossflow Turbine a. Turbine T13 bo. 600 mm unit b. Turbine base frame unit c. Pulley of turbine unit e. Flexible Coupling unit f. Plummer Block Bearing Set unit g. Flat belt unit h. Fence Guard unit I. adapter pipe unit j. Dynamic Balancing ls k. Heat treatment ls l. Pressure gauge unit 2 Electronic Load Controller unit 3 Ballast Load a. Air Heater (54 kva) unit b. Housing Ballast unit 4 Generator a. Syncronous Generator Stamford unit b. Generator base frame unit c. Pulley of generator unit 5 Accessories, Spare parts & Tools unit 6 Set up & Installation ls 7 Transportation & Packaging ls 8 Testing (welding) ls 9 Pre commissioning Trial Run ls sub total sub total sub total sub total sub total sub total sub total sub total sub total - 8-23 -
No Description Unit Quantity Unit Price Amount Total Price Rp Rp Rp IV DISTRIBUTION WORKS a. Transmission pole pcs b. Twisted Cable 4 * 70 mm 2 m 1 c. Twisted Cable 4 * 35 mm 2 m 1 d. Twisted Cable 2 * 16 mm 2 m 1 e. Accessories ls f. Installation expense ls V CONSUMER CONNECTION a. NYM Cable 2 * 1.5 mm 2 m 1 b. NYM Cable 3 * 1.5 mm 2 m 1 c. Electric Socket pcs d. Series Switch pcs e. Single Switch pcs f. Connector pcs g. Service Wedge Clamp pcs h. Cable Clam pack i. Plafond Fitting pcs j. Hanger Fitting pcs k. Rosset Wood pcs l. Cellophane Tape pcs m. Screw pack n. T - dus pcs o. MCB and housing unit p. Twisted Cable 2 * 10 mm 2 m 1 q. Grounding unit r. Installation Expense unit s MCCB Group unit TOTAL Rp - 8-24 -