Discuss the problems and countermeasures in highway project cost compilation?

As we all know, there are many factors that affect the rationality of highway project costs. One is the design factor, whether the design scale, standards and plans are appropriate, whether the design of bridges, tunnels and other structures is conservative, etc., have an impact on the number of projects. The second is the quota factor. Whether the consumption levels of various labor, materials and machines specified in the quotas and supplementary quotas of various projects are in line with the development level of social productivity in a certain period also affects the rationality of the project cost. Direct impact; third, market factors. Due to market uncertainty, prices frequently change between the project cost preparation period and the project implementation period, which brings great difficulty to accurately prepare material budget prices and then reasonably determine the project cost; fourth, preparation Quality factors, due to the uneven technical level and professional quality of project cost preparation personnel, as well as reasons such as rushing for time and rushing to complete tasks, lead to various problems in various aspects of project cost preparation, which in turn affects the project cost. rationality. In order to further improve the quality of project cost preparation and reduce the adverse impact of human factors, Zhongda Consulting mainly analyzes the various problems existing in the current highway project cost preparation from the perspective of project cost preparation, puts forward suggestions and countermeasures, and cooperates with the industry Colleagues discuss and improve together.

1. The impact of some common problems in design documents on cost preparation

1.1 Problems arising from lack of communication among various design professional working groups. For example, the quantity tables for subgrade earthwork and pavement projects often include corresponding quantities for interchanges, service areas, parking areas, toll stations, etc., while the quantities of interconnected interchanges, service areas, parking areas, and toll stations are designed separately.

1.2 In the design, part of the embankment is filled with other materials with higher strength, but the original earthwork quantity is not deducted; the upper road bed is treated with lime soil, and another quantity is mentioned, but the original fill section earthwork is not deducted. quantity.

1.3 The number of road trenches has been included in the earthwork of the roadbed, but the number has been redesigned during the pavement project.

1.4 The quantity of excavation for side ditches, drainage ditches, interception ditches and special slope control has been included in the subgrade excavation, but the quantity has been redesigned in the design of these structures.

1.5 When calculating the utilized, debited, and discarded cubic meters in the subgrade earthwork quantity table, the coefficient adjustment for converting natural compacted cubic meters into compacted cubic meters was not made, or the adjustment did not match the highway grade, causing the user, debited cubic meters to , The calculation of the quantity of discarded earthwork is incorrect; the table has not yet included the allocation and calculation of the increased quantity of earthwork caused by clearing topsoil, compacting before filling, and widening the filling of the road, so that this part of the quantity was missed in the design stage, but during implementation It happened again. This situation is very detrimental to the control of the quantity of earth and stone in the Pingwei District project.

1.6 Errors, errors, mistakes, and leaks that often occur in bridge projects. For example, the quantity of cast-in-place pile steel bars and concrete for full-width or half-width bridges is undercounted or overcounted by half, the main beam steel bars are overcounted, the bridge deck pavement steel bars are missed, the number of cylindrical pier concrete is undercounted by π, the number in the bridge summary table is inconsistent with the number in the detailed design, etc. wait.

As for the various problems that appear in the above design documents, the cost preparers often fail to discover them in time during the preparation process because they are in a rush for time and tasks, resulting in errors, errors, mistakes, and mistakes in the cost preparation of some projects. The phenomenon of leakage affects the rationality of project cost preparation.

2. Various problems that are likely to occur in the preparation of project cost

2.1 Problems in the preparation of material unit prices

(1) Basic information on materials - —The location, quality, output, transportation conditions, transportation distance, and whether it passes through toll stations and other conditions of the material yard are not fully investigated, or there is no on-site investigation at all and the unit price of materials from other projects is copied, or the unit price of materials from other projects is completely copied. The unit price preparation provided by the construction management unit resulted in a large gap between the prices of local materials such as quicklime, sand and gravel and the actual situation during the project implementation, making the project cost preparation inaccurate.

(2) The unit price of highway cement is generally high. Except for the lack of cement in Yan'an and Yulin areas in our province, other areas are rich in cement, and the quality is relatively stable. Local cement can meet the requirements when used in cement-stabilized pavement bases, masonry projects, and concrete below No. 40, but when the cost is compiled Qinling or other brands of cement are often used for bridges and tunnel structures, resulting in a large discrepancy between the procurement and transportation of cement and the actual situation of the project, resulting in a high unit price of cement.

(3) Frequent changes in the market prices of various types of steel and fuel materials have brought great difficulty to the reasonable preparation of budget unit prices, because some cost preparers lack the necessary analysis and understanding of the current market changes. According to the prediction, the price of some materials is too high or too low, which brings great difficulties to the phased control of project cost.

2.2 Main problems in the extraction of project quantities and the use of quotas

(1) Subgrade engineering

① Problems that often occur in subgrade earthwork projects. First, the selection of earth-moving machinery does not match the highway grade and terrain conditions. Some cost personnel have the idea of ????increasing the project cost as high as possible when compiling the project cost. Therefore, the mechanical power selected is generally too small, which invisibly increases the cost of earth-moving; second, Due to the low level of earthwork quota currently used, such as the quota for mechanical drilling and blasting of stonework, the mechanical coordination includes the first fixed transportation distance of bulldozers for transporting stonework, which is basically not the actual transportation of stonework by bulldozers at the current construction site. It does not match. For long-distance transportation, when using abandoned materials for loader loading and dump truck transportation, the quota is directly applied without adjusting the bulldozer's pushing consumption to 0, which makes the cost higher; thirdly, due to the lagging transportation quota level, For long-distance transportation of earth and stone with a transportation distance of more than 3 kilometers, the project quota is still applied to calculate transportation costs, which makes the unit price of the project prepared is abnormally high and seriously deviates from the actual construction reality.

② Problems arising in high slope protection and biological protection. As society has increasingly higher requirements for highway safety, landscape and environmental protection, the design of highways in recent years has strengthened the design of slope management and biological protection, and a new type of high slope protection project has emerged - anchor Grass planting on pole concrete frames, grass planting on anchor cable concrete frames, and new protection technologies - hydraulic spraying, guest soil spraying, and thick-layer matrix spraying. Since each province currently lacks supplementary quotas in this area, the unit prices compiled by different design units and different cost compilers are varied and chaotic. Basically, they are higher than the unit prices of corresponding expressway projects that have been implemented in the province, and some even deviate seriously. construction practice.

For example, in the construction drawing budget of a highway in the Qinling Mountains of our province, the anchor cable concrete frame protection is calculated. In addition to the concrete frame, steel bars, and supports, the anchor cable drilling, production, installation, and grouting costs are calculated according to The comprehensive price of the length of the anchor cable is 420 yuan/meter, which is far higher than the 280 yuan/meter of the supplementary quota compiled by other provinces during the review; the unit price of thick-layer substrate spraying is calculated as 120 yuan/square meter in some projects. Some are priced at 180 yuan/square meter, and some are priced at 150 yuan/square meter. The unit price difference is too big. It is understood that it is generally between 80 and 120 yuan/square meter.

(2) Pavement Engineering

① Recently, modified asphalt concrete is mostly used in the design of the upper and middle surface layers of highway pavements. Construction practice shows that the H4000 mixing plant mixes one furnace of modified asphalt. The mixing time of concrete is 5 to 10 seconds longer than that of ordinary asphalt mixing. It also affects the paving and rolling progress of the asphalt mixture, which virtually increases the shift consumption of mixing, paving, and rolling machinery. quantity. How should this be reflected in the cost? Since there is no corresponding supplementary quota yet, the cost preparation only adjusts ordinary asphalt to modified asphalt on the basis of fine and medium-grained asphalt concrete quotas (generally modified asphalt adds a processing fee per ton on the basis of the unit price of ordinary asphalt). 950-1090), without taking into account the increased cost due to reduced mechanical efficiency. So, how to prepare the project cost of modified asphalt concrete in the future remains to be discussed.

② When the compacted thickness of the stabilized soil base and subbase exceeds the prescribed thickness of one layer and needs to be laid in layers, the problem of adjusting the consumption of labor, tractors, graders, and road rollers. The current problem in the preparation is that the quota does not stipulate the thickness limit for layered paving. Therefore, when preparing some projects, the 16 to 20 cm and 30 to 40 cm are adjusted to two layers and three layers respectively, so that It is inconsistent with the minimum thickness of 15 cm and the appropriate thickness of 16 to 20 cm for single-layer construction stipulated in the technical specifications for road design and construction.

③Selection of production capacity of mixing equipment, setting quantity and mixture transportation distance. Some projects do not carry out construction organization design, and the setting of the mixing equipment is considered by the cost personnel in the preparation. Since the cost personnel do not carefully analyze the terrain of the project, the division of road bidding sections, the construction period, etc., the production capacity of the mixing equipment used , the set quantity is quite different from the actual situation of the project, making the calculation of pavement engineering costs inaccurate.

④Adjustment of the mix ratio of the pavement base layer and sub-base layer. In some projects, the mix ratio was not adjusted according to the design, or the adjustment was incorrect. For example, the base layer of some project pavements in our province uses 1.5:3.5:15:80 cement, lime, and fly ash comprehensive stabilized gravel. When some compilers apply the lime gravel quota for cost calculations, they directly add the cement amount to the quota. There was no reduction in the amount of lime material used, which virtually increased the cost and caused errors in the calculation of grassroots costs.

(3) Bridge and culvert project

① Cost calculation problem of filling semi-rigid material on the back of culvert platform. The design is to treat the back of the culvert platform and fill it with lime soil and other semi-rigid materials. When preparing the budget, the entire cost calculation was directly applied to the lime soil, soil, ash and other quotas for this part of the project, which is unreasonable. Since the amount of filling at the culvert location is generally not deducted from the subgrade earthwork, adding this cost will inevitably lead to double calculation of some project costs such as earthwork material costs and construction costs.

②Adjustment of hole formation quota for bored piles with non-standard pile diameter. The estimated budget quota has a rough division into the sub-items of the bored pile hole quota, and there are only some standard pile diameters, such as 1.0 meters, 1.2 meters, 1.5 meters, 2.0 meters, etc. In reality, non-standard pile diameter designs are often common. In order to further rationally determine the project cost, most of the provincial budget estimates reduce the quota according to a certain proportional coefficient when preparing drilling costs. Some are adjusted according to the pile diameter ratio, and some are adjusted according to the pile diameter cross-sectional area ratio. , the methods are different, resulting in large differences in project costs.

③ Due to the lack of understanding of the on-site construction conditions of special bridge types, the cost of some necessary large-scale supporting facilities during the construction was omitted. For example, some cost personnel often omit calculations when preparing budgets for continuous rigid frame and T-shaped rigid frame bridges. The brackets of the number blocks, the corner gantry on the top of the pier, the hangers on the closed section, the hangers or brackets on the cast-in-place side span tail sections, the lifting frames necessary for the construction of hollow piers above 20 meters, and the temporary elevators used for construction, etc.

(4) Tunnel Engineering

① The issue of quotas for excavation and lining of Class II surrounding rock. The design often provides the quantity of rocks classified as Category II based on soft rock. When the cost is compiled, the soil category quota is not applied according to the quota regulations, resulting in overestimation of costs.

② Calculation and use of tunnel growth coefficient. According to the quota regulations, when the length of the tunnel exceeds 1,000 meters, that is, when the construction working surface is more than 500 meters away from the tunnel entrance, for every additional 500 meters (if it is less than 500 meters, it will be counted as 500 meters), the labor days and machinery of the tunnel project will The number of classes will be increased by 5% according to the corresponding quota. However, the Ministry of Transportation often puts forward opinions during the review of preliminary design budget estimates that only the growth coefficient adjustment for the cave excavation quota is inconsistent with the quota regulations. In addition, the growth coefficient of tunnels in some projects does not meet the quota regulations based on the weighted average calculation.

③The problem of compiling the estimated cost of pipe trenches in the tunnel. Since the cast-in-place concrete lining quota of the tunnel estimate already includes the vault, side wall lining, concrete or mortar rubble backfill, tunnel pipe (water) ditch and cover plate, etc., some cost personnel have set up separate quota calculations when compiling The cost of the central pipe trench concrete, cement mortar plastering, etc. in the tunnel is included, so that the cost of this part is double calculated.

④The problem of compilation of ventilation civil construction costs for extra-long tunnel shafts. Due to the lack of corresponding content in the highway budget quota, when preparing this part of the project cost, the cost personnel sometimes adopt the method of inquiry and directly use the obtained project unit price; some directly apply the highway quota to calculate the cost; some use the coal quota to calculate the cost. There are different methods for preparing supplementary quotas after adjusting corresponding quotas for cost calculation. Since there are very few vertical risers and inclined shafts completed in the construction of domestic highways, it is unknown whether the calculations based on the above methods are consistent with the actual construction of the project. This is a question worth exploring.

⑤The connection issue with transportation and journey cost calculation. According to the provisions of the design document preparation method, the installation of lighting and ventilation facilities is part of the tunnel civil engineering design. However, the design unit often divides this part of the engineering design into the traffic engineering when dividing tasks. Therefore, some projects appear in the new tunnel engineering. The phenomenon of double counting or simultaneous omission in traffic engineering.

(5) Other projects and facilities and housing construction projects along the line

① Cost calculation issues for connecting lines, auxiliary roads, and branch lines. In recent years, during the construction implementation process, more connecting lines, auxiliary roads, branch lines and local bus projects have appeared, and the mileage has become longer and longer, which has expanded the scale of construction drawing design and greatly increased the cost, which has brought difficulties in controlling the cost of the project at this stage. Comes adverse effects.

Secondly, when compiling the cost of this part of the project, since this type of project generally adopts technical standards of Class II or below, according to the supplementary compilation regulations of Shaanxi Province, the project cost should be separately prepared for Class II and III projects, and then remitted to the construction and installation fee. However, for the convenience of calculation, cost personnel often directly adopt highway standards, resulting in overestimation of costs.

② Summary issues of traffic engineering and housing construction projects. Transportation projects and housing construction projects are separately prepared according to the quotas and preparation methods of relevant ministries and commissions. When remitting construction and installation fees to the main project, some projects do not reduce the remitted fees in accordance with the "Transportation Engineering Preparation Regulations" of the Ministry of Communications. Some projects are reduced The coefficient is wrong. When the construction and installation fees for professional projects compiled by quotas from other ministries and commissions are remitted to the construction and installation fees for the main highway projects, they should be reduced by a coefficient based on the principle of keeping the original cost level unchanged. However, the reduction formula stipulated by the Ministry of Transport does not take into account the construction technology and equipment fees. The reduction factor causes the remitted costs to include construction technology and equipment costs.

2.3 Problems in the compilation of other project construction costs

(1) The calculation of compensation costs for land acquisition and demolition is inaccurate. The inaccurate cost calculation mainly includes three aspects. First, the design of the land acquisition and demolition quantity is inaccurate, or too many changes during the implementation period cause the quantity to increase significantly, making it difficult to control the cost; second, the land classification, demolition of buildings The classification of types is inaccurate and greatly differs from the actual construction, making the cost calculation unreasonable; thirdly, due to the current impact of the national rural protection strategy, it is difficult to determine the compensation standards for land acquisition and demolition in some areas, making the calculation of the cost unreasonable. There are too many determining factors, which brings great difficulties to the reasonable preparation of expenses.

(2) The calculation of research and experiment fees and survey and design fees is unreasonable. If these two costs are not calculated according to the contract or agreement during the construction drawing design stage, the included costs will far exceed the preliminary design estimate approval fee.

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