The calculation of estimates for earthworks has its own characteristics. With a skillful approach, you can easily "wind up" the estimate to the desired amount. Consider what the cost of earthworks consists of.
First of all, you need to look into the PIC - the construction organization project and understand what mechanisms will be used in the project. It is also very important to look at the data geological surveys: soil group, groundwater level, vegetation layer thickness, wet soil or dry. Is the pit or trench fastened with boards or not?
Depending on this, some prices may be added:
When removing soil, you can additionally apply prices for work on the dump, as well as for soil disposal. Important! For the removal of soil, there are special places, landfills. And the landfill there is by no means free. Therefore, you need to get a certificate of how much soil you have utilized and present it to the customer, and be sure to include these costs in the estimate!
Important point! Backfill prices usually include a distance of 20 km, but what if your quarry is further away? We also look at the POS and look for a transport scheme, where it is prescribed from where and with what transport arm materials for your construction site will be transported: sand, crushed stone, concrete, etc.
It would also be nice to understand at what price the supplier of the ASG is selling in the area of your construction. Maybe he is a monopolist there and inflates market prices by 2 times? Then estimated prices are no longer suitable and it is necessary to use its price list in the estimate for approval by the customer.
We briefly talked about the "chips" in the prices. Now let's move on to the important question of how to calculate the volume of earthworks?
What is important to consider here: 7% of the excavated soil must always be finished manually. And also do not forget to take away the volume of the plant layer.
When backfilling, it must be remembered that here the actual volume will depend on the compaction factor. Well, do not forget to subtract the volume of the foundation being laid, which many people forget!
These and many other subtleties are taken into account by the specialists of our company when compiling budget documentation! We want you to earn more with our estimates!
To calculate the volume of earthworks in preparation estimates for construction work you need to decide on the following points:
The name "black" refers to those marks of the daytime surface of the earth that exist before the start of earthworks. They are installed using geodetic survey data and put on the drawings on the cartogram of the upcoming earthworks. Exhibited necessary for preparation estimates for earthworks black marks, including those on the geological sections of boreholes, but they can only be used if there is no survey data.
Setting the groundwater level (GWL) is carried out according to the sections of boreholes, which are performed for the construction site in accordance with existing rules. If groundwater is present within the excavation, then not only those soils that are below the GWL, but also located above this level by the following value, should be considered wet:
AT estimated norms and prices for the development of wet soil do not take into account drainage work. Their preparation cost estimates for earthworks manually or using computer programs, you need to additionally determine one of the ways:
In the calculations, it is necessary to take into account such points as the intensity of the inflow of groundwater, the duration of the drainage and the use of drainage facilities.
The strength of the inflow for groundwater is taken from the conclusion of the engineering-geological conditions, which is a necessary element for compiling local estimates for earthworks on a specific construction site. The duration of the drainage and the means of drainage used (types of pumps) should be specified in the basic provisions describing the organization of the construction.
For estimates and rates differentiation by groups of soils and rocks is provided, depending on the severity of their development. Characteristics of developed soils during preparation estimates for earthworks are taken from the geological sections of boreholes that are laid on the building site. The soil group is always determined in layers, the thickness of the soil layer in the same groups for different wells should be reduced to an average value.
Conditions for performing earthworks, which largely determine the final value at determining the estimated cost, should be taken from the construction organization project.
To such conditions, taken into account when developing local estimates for earthworks, include the following points.
1. Method of work - manually or using earth-moving machines. For example, when developing pits for buildings, the distribution of work is as follows:
2. Types and characteristics of earth-moving machines used. AT samples of estimates for earthworks in the construction of residential and civil buildings, single-bucket excavators (bucket up to 1 cubic meter), draglines (bucket up to 0.5 cubic meters) and bulldozers (power up to 100 W) are usually indicated.
3. Distance of soil movement, availability of opportunities for its temporary storage and use of surplus. In case of unsuitability for exploitation of excess soil, construction and landfill debris, it is taken out of the construction site. All this must be taken into account when construction budget calculation.
Excess soil obtained during the development of pits for buildings, which can be used for backfilling, is taken out for temporary storage. The distance of export in this case should not be more than 1 kilometer, if the conditions and territory construction site allow it.
The distance of supply of the missing soil for the purpose of backfilling and the distance of removal of excess soil in each case is determined individually and is taken into account in estimate for earthworks.
4. Types and characteristics Vehicle. Usually, the soil extracted by excavators is taken out on dump trucks with a carrying capacity of 2.25-12 tons.
Local estimates for certain types of construction and installation work, as well as the cost of equipment is compiled based on the following data:
Local estimated calculation (estimate) is compiled:
When designing complex buildings and structures carried out by several design organizations, as well as when forming an estimated cost for launch complexes, it is allowed to draw up two or more local estimates (estimates) for the same type of work.
In local cost estimates (estimates), data are grouped into sections according to individual structural elements of the building (structure), types of work and devices in accordance with the technological sequence of work and taking into account specific features certain types of construction. According to buildings and structures, division into underground part(works of "zero cycle") and aerial part.
Local estimate calculation (estimate) may have sections:
The cost of work in local estimates (estimates) as part of the estimate documentation can be given in two price levels:
4.6. When compiling local estimates, prices from the corresponding collections are used, while in each position of the local estimate calculation the code of the norm is indicated, consisting of the collection number (two characters), the section number (two characters), the serial number of the table in this section (three characters) and the serial number of the norm in this table (one - two characters). The parameters of individual characteristics (length, height, area, mass, etc.) given with the word "to" should be understood inclusive, and with the word "from" - excluding the indicated value, i.e. over.
When drawing up local estimates (estimates), the conditions for the production of work and complicating factors are taken into account.
When referring in local budget calculations (estimates) to the technical part or introductory instructions for price collections or other regulations in the column "cipher, numbers of standards and resource codes" after the number of the collection and the price, it is indicated in the initial letters TC or VU and the number of the corresponding item, for example: PM-5 or VU-4, and when taking into account in the positions of local estimates (estimates) coefficients (given in Appendix N 1), taking into account the conditions for the production of work, column 2 of the estimate indicates the value of this coefficient, as well as the abbreviated name and paragraph of the regulatory document.
When compiling local estimates (estimates) for work on the reconstruction, expansion and technical re-equipment of existing enterprises, buildings and structures, complicating factors and conditions for the production of such works are taken into account using the appropriate coefficients given in the relevant collections of estimated norms and prices ("General Provisions") .
Works performed during the repair and reconstruction of buildings and structures, similar to technological processes in new construction, should be normalized according to the relevant collections of GESN-2001 for construction and special construction works (except for the norms of the collection of GESN N 46 "Work in the reconstruction of buildings and structures") using coefficients of 1.15 to labor costs and 1.25 to norms operating time construction machines. The indicated coefficients may be used in conjunction with the coefficients given in Appendix N 1 to this Methodology.
When carrying out earthworks on the territory allotted for construction in places that are duly attributed to areas of former military operations, it is recommended to apply a coefficient of 1.4 .
For works, the production technology of which provides for welding of metal structures, rolled metal, steel pipes, sheet metal, embedded parts and other metal products, elemental estimated norms and unit rates are developed from the condition of using carbon steel.
When using stainless steel, it is recommended to apply a coefficient of 1.15 to the labor costs provided for in unit prices.
The cost determined by local estimates (estimates) may include direct costs, overheads and estimated profit.
Direct costs take into account the cost of resources required to complete the work:
As part of direct costs, separate lines may include the difference in the cost of electricity received from mobile power plants, compared with the cost of electricity supplied by the Russian energy system, and other costs.
Overhead costs take into account the costs of construction and installation organizations associated with the creation general conditions production, its maintenance, organization and management.
Estimated profit includes the amount of funds needed to cover individual (general) expenses of construction and installation organizations for the development of production, the social sphere and material incentives.
The accrual of overhead costs and estimated profit in the preparation of local estimated calculations (estimates) without dividing into sections is carried out at the end of the estimate calculation (estimate), following the result of direct costs, and when forming by sections - at the end of each section and in general according to the estimate calculation (estimate ).
When using the resource or resource-index method, it is recommended to use sample No. 4 (Appendix No. 2), in which the allocation, summation of resource indicators with the determination of the cost in the corresponding price level, or sample No. 5 (Appendix No. 2), on the basis of which resource indicators are allocated and summed up on the local resource sheet, and then the cost of work (the amount of costs) is determined according to sample No. 4.
In cases where, in accordance with design solutions dismantling of structures or demolition of buildings and structures is carried out according to structures, materials and products suitable for reuse, following the results of local estimated calculations (estimates) for dismantling, demolition (transfer) of buildings and structures, refundable amounts are given for reference (amounts that reduce the amount allocated by the customer capital investments). These amounts are not excluded from the result of the local budget calculation (estimate) and from the scope of work performed. They are shown in a separate line called "Including refundable amounts" and are determined on the basis of the nomenclature and quantity of structures, materials and products received for subsequent use, also given after the calculation (estimate). The cost of such structures, materials and products as part of the refundable amounts is determined at the price of the possible sale, minus from these amounts the costs of bringing them into a usable condition and delivery to storage sites.
The cost of materials obtained in the course of associated mining (stone, crushed stone, sand, timber, etc.), if it is possible to sell them, is recommended to be taken into account at the prevailing prices in the region.
If it is impossible to use or sell materials from dismantling or associated mining, their cost in refundable amounts is not taken into account.
It is recommended to distinguish structures, materials and products included in refundable amounts from the so-called wraparound materials (formwork, fastening, etc.), which are used several times in accordance with the technology of construction production when performing certain types of work.
When performing certain types of work in accordance with the construction technology, certain materials (formwork, fastening, etc.) are used several times, i.e. turn around. Their repeated turnover is taken into account in the estimated norms and the prices compiled on their basis for the corresponding structures and types of work. In cases where it is impossible to achieve the normative number of turnover of industrial formwork, fasteners, etc. at the facility, which must be justified by the PIC, the norm is adjusted.
The cost of equipment, furniture and inventory is included in local estimates(estimates).
When using equipment that is listed in fixed assets, suitable for further operation and planned for dismantling and transfer to a building under construction (reconstruction), local estimates (estimates) provide only funds for the dismantling and re-installation of this equipment, and after the result of the estimate, reference is shown his book value, taken into account in the total cost limit to determine the technical and economic indicators of the project.
Any new construction, or even repair work, for example, the replacement of a heating main, begins with earthworks. The correct calculation of the volume of earthworks and the correct determination of the composition of these works is of great importance in the preparation of estimates.
Earthworks are all works related to the movement, development, compaction of soil.
The calculation of the volume of all earthworks can be reduced to the calculation of the volume of certain geometric shapes. Here are a couple more basic definitions.
Trench- an excavation in the ground of an elongated shape, as a rule, trapezoidal, extended, created for the installation of communications, for example, various pipelines, or for the installation of strip foundations.
Pit - excavation in the ground, more extensive in area, intended for the construction of foundations for buildings and structures, various bases for structures.
When drawing up estimates for earthworks, it is important to know not only the basic estimated norms and rules, but also take into account the rules for the production of earthworks, taken into account in SNiP 3.02.01 "Earthworks, bases and foundations". final estimated cost work will depend not only on the amount of work and the type of soil, but also on many factors that must be consecrated in the project, or in additional explanations.
Some of the main additional factors to consider when drawing up an estimate for earthworks:
As mentioned above, the calculation of volumes is reduced to the calculation of the volumes of geometric shapes.
These figures usually do not have rectangular shape, since slopes are arranged in pits and trenches. The steepness of the slopes of pits, trenches, which are arranged without any fastenings, is selected based on the group of soils located at the place of work. The steepness of the slopes is taken according to the following table.
Fig.4 Selecting the steepness of the slope
It should be remembered that if various types of soils are layered at the work site, the steepness of the slopes must be chosen according to the weakest soil. When drawing up estimates, if there is no data on the types of soils, it can be taken: in wet soils not bulk 1: 1, in wet bulk soils - 1: 1.5.
To calculate earthworks, you need to know the width and length of the trench along the bottom.
The width of the pit when laying pipelines can be determined from the following table:
Fig.5 The smallest width of the trench
The depth of development should be taken according to the mark of the top of the pit and the mark of the bottom of the foundation or pipeline (it is important not to forget to take into account the thickness of the underlying layers or bases).
After all the necessary initial data are known, you can proceed to the calculations. The volume of developed soil in the trench is determined by the formula.
Where a is the width of the trench along the bottom.
C is the inverse ratio of the slope
h - depth
L - length
Formula for calculating the amount of work in the pit.
V=F+pch/2+4/3 (ch) 2 h (2)
Where: h - depth
F- Pit base area
P - base perimeter
C is the inverse ratio of the steepness of the slopes.
If there are elevation differences in the pit, for example, it is necessary to build foundations at different depths, to simplify the calculations, the pit can be conditionally divided into several parts with the same heights.
For carrying out land works of varying complexity, it is most often necessary to involve workers and special equipment. All this must be taken into account before proceeding to direct implementation. To do this, the contractor draws up an estimate, which is then approved by the customer. Sometimes the client independently conducts preliminary calculations in order to have an idea of the price of the issue.
If it is necessary to involve a contractor under a formal agreement (the company hires a contractor and reflects the costs in the documents), then the estimate is binding document to be attached to the report. If the customer is an individual (private) person, then calculations are made at will.
At the same time, in practice, estimates are drawn up almost always. This is necessary first of all, so that the customer can assess the upcoming costs and decide on the feasibility of the work.
In the case of land works, the approach to budgeting can be of two types:
Sometimes it may be necessary to draw up several estimates in order to evaluate the difference in the final amount and decide on a suitable option.
The estimate for any land work requires the inclusion in the calculations of standard cost items:
What exactly will become the main expense item when drawing up estimates for repair work depends on the specific type of task. To draw up an estimate, you must first clarify all the wishes of the client, as well as inspect the object with which it will be necessary to work (sometimes it may be necessary to use more expensive equipment or an additional payment for the complexity of the work).
Sometimes it will be advisable to include the costs of obtaining required documents. For example, in order to carry out a land survey and then record the results, some fees will need to be paid. But this applies only to those cases when an organization offers its client a turnkey facility - then all costs from clearing the territory to legalization should be included in the estimate provided to the customer for approval.
When making calculations, it is also important to take into account state standards. For some objects or types of work, these standards are very strict and any deviation may lead to the fact that the object cannot be legalized.
Standards in particular affect the following parameters:
Sometimes it may be necessary to carry out not a comprehensive improvement of the site, but the performance of some specific work. In this case, the estimate will be calculated for each case separately. The most common types of estimates for land works include:
Thus, in any estimate for land work, mandatory items must be indicated. At the same time, the detailing of each of them completely depends on what kind of work should be carried out. Only after clarifying all the details and inspecting the site, it will be possible to make detailed calculations.
