Derivation of unit cost calculation formula for th

Derivation of unit cost calculation formula of water supply pipeline

pipe cost accounts for a large proportion in the investment of water supply engineering, so the optimization calculation method should be adopted in the design of water supply pipeline, and the calculation formula of unit cost of pipeline is involved in the calculation. The calculation formula of different pipes is different in different places. According to the actual situation of Shandong Province, this paper deduces the unit cost formula of five kinds of pipes: steel pipe, ductile iron pipe, sand glass fiber reinforced plastic pipe, prestressed reinforced concrete pipe and steel cylinder cement pipe. 1. Relevant data of Shandong Province. The prices of various pipes and the labor prices of regular materials in Shandong Province are shown in Table 1 and table 2

diameter/mm steel pipe/(yuan · m-1) ductile iron pipe/(yuan · m-1) sand glass steel pipe/(yuan · m-1) prestressed reinforced concrete pipe/(yuan · m-1) steel pipe cement pipe/(yuan · m-1) 15087.00100.00130.0034.00 200123.00135.00160.0049.00 250154.00177.00190.0065.00 300243.002 make the upper and lower jaw not concentric 24.00225.0096.00 400319.00335.00320.00155.00 500398.00463.00430.00100 88.00 600532.00612.00620.00240.00520 00778.00690.00275.00680.. 00960.00850.00360.00740.. 001164.00980.00400.00850.. 001385.001200.00480.00960.. 001891.001450.00650.001300.. 00 2200.00850.001500.. 00 2750.00 1740.. 00 3700.00 2140.. 00 2600.. 00 2820.00 Table 1 pipe price table 2 regular material labor price

project name unit price/yuan project name unit price/yuan labor d12.5 gravel m332.65 cement t280.00 steel pipe and fittings t3800.00 sawn timber m3200.00 cast iron pipe fittings t5000.00 steel t2300.00 prestressed reinforced concrete pipe t750.00 machine-made red brick thousand 180.00 valve t1500.00 sand m342.41 steel fittings t2800.00 kw · h0.70

2 calculation principle of pipe cost 2.1 standard diameter pipe Calculation of pipeline cost

according to the investment estimation method given in volume 10 of water supply and Drainage Design Manual: technical economy volume (Second Edition), the unit cost of standard pipe diameter of various pipes of water supply pipeline is calculated by using the original data and the data provided in the manual. The calculation process is as follows:

① labor cost: index labor days multiplied by labor unit price

② subtotal of material cost = main material cost + other material cost

other material cost = index other material cost × [adjusted other material cost/(indicator material cost subtotal - indicator other material cost)]

③ machinery usage fee = [adjusted (labor cost subtotal + material cost subtotal)]/[indicator (labor cost subtotal + material cost subtotal)] × Index machinery usage fee

④ index base price: the sum of adjusted labor cost, material cost and machinery usage fee

⑤ other engineering costs: the adjusted other engineering costs are the adjusted index base price multiplied by the index other engineering cost rate (calculated by 8% of the main project)

⑥ comprehensive cost = adjusted (index base price + other engineering costs) × Comprehensive cost rate (33.6% for water supply works)

⑦ construction and installation engineering cost: adjusted (index base price + other engineering costs + comprehensive costs)

⑧ calculate the price difference coefficient

⑨ other costs of engineering construction = adjusted construction and installation costs × Rate of other costs of engineering construction (8.24%)

⑩ basic budget cost = after adjustment (the "13th five year plan" veil of construction and safety new materials is gradually lifted + other costs of the project) × Basic reserve rate (10%); The experimental error of electronic universal experimental machine is basically very small

⑾ total cost = adjusted (construction and installation engineering cost + other costs of engineering construction + basic reserve fund)

12 calculate the unit cost of various water supply pipelines

the cost table of pipes including construction and installation costs is shown in Table 3. Table 3 the cost of various pipes

pipe diameter/mm steel pipe/(yuan · m-1) ductile iron pipe/(yuan · m-1) sand glass steel pipe/(yuan · m-1) prestressed reinforced concrete pipe/(yuan · m-1) steel pipe cement pipe/(yuan · m-1) die casting parts account for about 80% of the consumption 57 6549 8811 84232.2 determination of parameters in the pipeline unit cost formula

the pipeline unit cost formula is generally c=a+b D α Formal representation [1], in which the calculation steps of each parameter are as follows:

① take the unit cost in Table 3 as the ordinate and the pipe diameter as the abscissa, draw the cost points corresponding to each pipe on the grid paper, connect the points into a smooth curve and extend to the y-axis intersection. The ordinate is α Value

② use the least square method to solve B, α Value: c=a+b D α Shift to c-a=b D α， Take logarithm on both sides to get:

lg (C-A) =lgb+ α LGD makes a=lg (C-A), b=lgb, d=lgd, a=b+ α D

then calculate Ci, ci-a, Di, AI, Di, di2, Aidi in a list, and replace ∑ AI, N, ∑ di ∑ d2i with the above equation group

③ unit cost formula of 5 kinds of pipes

from the above calculation, the unit cost formula of 5 kinds of pipes can be obtained, which is specifically expressed as follows (using the unified form c=a+b D α)：

steel pipe: c=160+3117d1.549

ductile iron pipe: c=80+3205d1.394

prestressed concrete pipe: c=30+2028d1.347

sand glass steel pipe: c=180+2772d1.660

steel cylinder cement pipe: c=480+2467d1.4663 conclusion the unit cost calculation formula of water supply pipeline is related to many factors, and the relevant parameters in various regions are different. According to the actual situation of Shandong Province, this paper uses the least square method to estimate the unit cost formula of five commonly used pipes, so as to invest in pipeline engineering