A, the significance of the correct calculation of quantities

Engineering quantity refers to the engineering quantity of each sub-project or structural member expressed in natural or physical measurement units.

Natural measurement units are based on the natural properties of objects. For example, light boxes, mirror boxes and counters take "one" as the unit of measurement, and clothes hangers, curtain rods and towel racks take "root" or "cover" as the unit of measurement.

Physical measurement units are based on some physical properties of objects. For example, the unit of measurement for wall plastering is "m2", and the unit of measurement for curtains, curtain rails, stair handrails and railings is "m".

The significance of correctly calculating the engineering quantity is mainly manifested in the following aspects:

1, project valuation is based on engineering quantity, so the accuracy of engineering quantity calculation directly affects the accuracy of engineering cost and investment control of engineering construction.

2. The engineering quantity is an important basis for the construction enterprise to work out the construction operation plan, arrange the construction progress reasonably and organize the on-site labor, materials and machinery.

3. The engineering quantity is an important basis for the construction enterprise to compile the statistical report of the project image progress and settle the project price with the project construction investor.

Second, the basis of engineering quantity calculation

1, atlas of construction drawings and supporting standards

Construction drawings and supporting standard atlas are the basic data and basis for engineering quantity calculation. Because the construction drawing fully reflects the structural structure, dimensions of each part and engineering practice of the building (or structure).

2, budget quota, bill of quantities valuation specification

According to the different engineering valuation methods (quota valuation or bill of quantities valuation), the corresponding engineering quantity calculation rules are selected to calculate the engineering quantity, the construction drawing budget is compiled, and the engineering quantity is calculated according to the budget quota and its engineering quantity calculation rules; If the bill of quantities is prepared for project bidding, the quantities shall be calculated according to the calculation rules of quantities in the appendix of "Pricing Specification".

3, construction organization design or construction scheme

The construction drawings mainly show the entity project of the proposed project, and the specific construction methods and measures of the sub-projects shall be determined according to the construction organization design or construction scheme. For example, the calculation of foundation earthwork, whether the construction method is manual excavation or mechanical excavation, whether it is necessary to put slopes around the foundation pit, reserve working faces or do support protection, etc. , should be based on the construction organization design or construction scheme.

Third, the method of engineering quantity calculation

(A) the basic method of engineering quantity calculation

Before the calculation of engineering quantity, the calculation order of divisional works should be arranged first, and then the calculation order of each subdivisional work in divisional works should be arranged. The calculation sequence of partial projects should be determined according to its related factors (see Chapter 2 and Section 2 for the reasonable arrangement of calculation sequence of quantities).

The calculation sequence of different parts of the same sub-project is the basic method of engineering quantity calculation. Sub-projects are composed of the same type of components or projects with the same engineering practice. For example, "prestressed hollow slab" is a sectional project, but there are various models because of different building bays and different load levels of slabs. The calculation method is to count and summarize the quantity layer by layer according to the floor model, and then look up the table to calculate the corresponding concrete volume and steel bar consumption. Another example is "general plastering of interior walls", which is a sectional project. According to the calculation scope, it should include double plastering of external wall and internal wall. The calculation method is to add up the plastering of the inner wall of the same engineering practice on each floor, and calculate the total plastering area of the inner wall according to the provisions of the engineering quantity calculation rules.

It should be noted that the engineering contents and measurement units of the projects listed in the design drawings must be consistent with those of the corresponding projects in the corresponding engineering quantity calculation rules, and shall not be changed at will.

In order to ensure the accuracy of engineering quantity calculation, the effective digits of engineering quantity shall meet the following requirements: (1) Take "ton" as the unit, with three digits reserved after the decimal point and the fourth digit rounded off; Take "cubic meter", "square meter" and "meter" as units, with two decimal places reserved and the third place rounded; Take "individual" and "item" as the unit, and take the whole number.

The calculation of engineering quantity should be based on different situations, and the following methods are generally adopted:

1, calculated in clockwise order.

Take the upper left corner of the drawing as the starting point, calculate clockwise in turn, and then circle the drawing once in the calculation order and then return to the starting point. This method is generally used for the calculation of various strip foundations, walls, cast-in-place and prefabricated members, and its characteristic is that it can effectively prevent omission and repeated calculation.

2, calculated in numerical order

The structural diagram includes different types and models of components, which are distributed in different parts. In order to facilitate calculation and recheck, it is necessary to number the components in the order of number, and then calculate.

3, according to the number of shaft calculation

For the engineering quantity with complex structure, in order to facilitate calculation and review, some sub-projects can be calculated by the shaft number method of construction drawing. For example, in the same plane, when the length and width of the belt foundation are inconsistent, it can be calculated in the order of axis A (① ~ ③) and axis B (③, ⑤, ⑦).

4, piecewise calculation

When the cross section of a long member changes, it can be calculated according to the cross section. Such as multi-span continuous beam, when the cross-section height or width of one span is different from that of other spans, it can be calculated in sections according to the size between columns. If the section of floor ring beam at the entrance of doors and windows is thickened, the quantities of concrete and steel bars should be calculated in sections.

5. Hierarchical calculation

This method is commonly used in engineering quantity calculation, such as wall, component layout, wall cylindrical decoration, floor slab and floor slab practice. , to layered calculation, and then put each layer of the same project summary.

6. Regional calculation

When the plane design of large-scale engineering projects is complicated, the plane plan can be divided into several areas at expansion joints or settlement joints to calculate the engineering quantity respectively, and then the projects with the same characteristics in each area can be combined for calculation.

(2) Rapid calculation method of engineering quantity

This method is a simple and quick method based on the basic method and according to the calculation characteristics and laws of components or subdivisional works. Its core content is to use the bill of quantities, the special table for engineering quantity calculation and various calculation formulas to calculate skillfully, so as to achieve the purpose of fast and accurate calculation (see chapter 3, rapid calculation methods and skills of itemized engineering quantities).

Four. Introduction of valuation specification

The Valuation Code is jointly issued by the Ministry of Construction and the General Administration of Quality Supervision, Inspection and Quarantine, and is used for bidding activities of construction projects. Its purpose is to standardize the valuation behavior of construction engineering bill of quantities and unify the compilation and valuation methods of construction engineering bill of quantities.

(A) the general concept

The bill of quantities valuation method is a project cost valuation method in which the tenderee provides the quantities according to the unified national engineering quantity calculation rules, and the bidders independently quote according to the bill of quantities, and win the bid at a low price after evaluation.

Bill of Quantities is a detailed list of partial and sub-project items, measures, other project names and corresponding quantities of the proposed project compiled by the tenderee according to the unified project compilation, project name, measurement unit, calculation rules of quantities, construction drawings and actual construction site, including partial and sub-project bill of quantities, measures and other project lists.

Bill of quantities valuation refers to all the expenses required by the bidder to complete the bill of quantities provided by the tenderer, including partial project fees, measures project fees, other project fees, fees and taxes. The bill of quantities is priced by comprehensive unit price.

The valuation activities of bill of quantities of construction projects should follow the principles of objectivity, justice and fairness. In addition to this specification, it shall also comply with the provisions of relevant national laws, regulations, standards and norms.

(2) the contents of the valuation statement

The pricing specification consists of two parts: the text and the appendix, which have the same effect.

1, text

The text is divided into five parts, including general principles, terminology, bill of quantities compilation, bill of quantities valuation, bill of quantities and its valuation format, etc. , clearly defined the scope of application, the principles to be followed, the rules to be followed in compiling the bill of quantities, the rules of valuation activities of the bill of quantities, the bill of quantities and its valuation format.

2. Appendix

The appendix includes five parts: Appendix A, Appendix B, Appendix C, Appendix D and Appendix E, including project code, project name, measurement unit, engineering quantity calculation rules and project content.

(1) Appendix A: Construction engineering bill of quantities items and calculation rules, applicable to industrial and civil buildings and structures.

(2) Appendix B: The items and calculation rules in the bill of quantities of decoration works are applicable to the decoration works of industrial and civil buildings and structures.

(3) Appendix C: Installation project bill of quantities items and calculation rules, applicable to industrial and civil installation.

(4) Appendix D: municipal engineering bill of quantities items and calculation rules, applicable to urban municipal construction projects.

(5) Appendix E: The bill of quantities of landscaping works and its calculation rules are applicable to landscaping works.

(C) the characteristics of "pricing norms"

1, required item

Mainly in the following two aspects:

(1) The Code of Valuation was promulgated by the national construction administrative department in a standardized form according to the mandatory national standards, which stipulates that all large and medium-sized construction projects that use state-owned assets or mainly use state-owned assets should implement this code.

(2) The valuation specification clearly stipulates that the bill of quantities is an integral part of the tender documents, and stipulates the rules that the tenderer should follow in compiling the bill of quantities and the rules that the bidder should follow in compiling the tender quotation, and forces the compilation of the bill of quantities to achieve four unifications, namely, unified project code, unified project name, unified measurement unit and unified engineering quantity calculation rules.

2. Competition

Bill of quantities valuation is based on the separation of "quantity" and "price". The valuation specification only stipulates the calculation of "quantity", but does not stipulate the consumption standard, unit price, construction methods and measures of artificial machinery reflected in the comprehensive unit price. Therefore, in the project bidding, the bidder can bid according to the construction technology and management level of the enterprise itself, the consumption standard of the three elements of manual machinery, the amount of overhead fee and the expected profit.

Step 3 be practical

The project name and calculation rules of BOQ project in the appendix of "Pricing Specification" represent engineering entity projects. The project name is clear and clear, and the calculation rules of BOQ are concise and clear, especially the project characteristics and engineering contents. It is easy to determine the specific project name and tender offer when compiling BOQ.

(four) the mandatory provisions of the "valuation standard"

Article 1.0.3, all large and medium-sized construction projects that use state-owned assets or mainly use state-owned assets shall implement this specification.

Article 3.2.2, the partial bill of quantities shall be calculated according to the unified project code, project name, unit of measurement and engineering quantity calculation rules specified in Appendix A, Appendix B, Appendix C, Appendix D and Appendix E. ..

Article 3.2.3, the project code of partial bill of quantities, 1 to 9 digits, shall be set according to the provisions of Appendix A, Appendix B, Appendix C, Appendix D and Appendix E; According to the project name of the bill of quantities of the proposed project, ten to twelve people are set up, and they are compiled in turn from 00 1.

Article 3.2.4 (1), the project name of the partial bill of quantities shall be determined according to the project name and project characteristics in Appendix A, Appendix B, Appendix C, Appendix D and Appendix E, combined with the actual situation of the proposed project.

Article 3.2.5, the unit of measurement of partial bill of quantities shall be determined according to the units of measurement specified in Appendix A, Appendix B, Appendix C, Appendix D and Appendix E. ..

Article 3.2.6 (1), the engineering quantity shall be calculated according to the engineering quantity calculation rules specified in Appendix A, Appendix B, Appendix C, Appendix D and Appendix E.

(V) Definitions of terms in the valuation specification

1, bill of quantities

Show the detailed list of partial projects, measures, other projects and corresponding quantities of the proposed project.

2. Project coding

It is represented by twelve Arabic numerals. One to nine digits are unified codes, of which one to two digits are appendix sequence codes, three to four digits are professional engineering sequence codes, five to six digits are partial engineering sequence codes, seven, eight and nine digits are subentry engineering name sequence codes, and ten to twelve digits are list engineering name sequence codes.

3. Comprehensive unit price

Labor cost, material cost, machinery use fee, management fee and profit required to complete the unit project specified in the bill of quantities, and risk factors are considered.

4. Measures and projects

Non-engineering entity projects in technology, life and safety. Complete the project construction before and during the project construction.

5. Reserves

The amount reserved by the bidder for possible changes in quantities.

6. General contracting service fee

Cooperate and coordinate the expenses required by the tenderee for engineering subcontracting and material procurement.

7, sporadic work project fee

The cost and estimated quantity of work required to complete the sporadic work proposed by the bidder.

8. Consumption quota

The construction administrative department shall, according to the reasonable construction organization design and normal construction conditions, determine the average social consumption of labor, materials and machinery required for the production of qualified products of the specified units of measurement.

9, enterprise quota

The consumption of labor, materials and machinery determined by the construction enterprise according to the construction technology and management level of the enterprise and the relevant project cost data.

10, pre-tender estimate

Pre-tender estimate refers to the expected tender price compiled by the tenderee or the engineering cost consulting agency entrusted by it according to the bill of quantities and related requirements in the tender documents, the actual situation of the construction site, the reasonable construction method and the relevant engineering cost valuation methods formulated by the construction administrative departments of provinces, autonomous regions and municipalities directly under the Central Government. In the project bidding under the mode of bill of quantities valuation, the pre-tender estimate is not the standard price that determines whether the bid can be won, but a reference price when evaluating and determining the bid.

1 1, tender offer

Bidding quotation refers to the project bidding price compiled by the bidder according to the bill of quantities and related requirements in the bidding documents, the actual situation of the construction site, the proposed construction scheme or construction organization design, the enterprise quota (or referring to the average social consumption quota issued by the local construction administrative department), the market price information, the construction technology and management level of the enterprise itself.

12, construction project

A construction project refers to an engineering project with project approval documents and design task books approved by relevant departments, which is independently accounted for economically and managed administratively.

The name of a construction project is generally named after the name of the construction unit, and a construction unit is a construction project. For example, XX garage, XX cement plant, XX college and XX hospital are all construction projects.

A construction project is composed of several single projects, and some construction projects, such as reconstruction and expansion projects, may also be composed of a single project.

13, single project

A single project refers to a construction project that has independent design documents and can independently exert its production capacity and use efficiency after completion.

A single project is an integral part of a building project. For example, the workshop, office building, power distribution room and canteen of a factory, and the outpatient building, office building, inspection building, inpatient building, canteen and residential building of a hospital are all single projects.

14, unit project

Unit project refers to an engineering project with independent design documents, which can independently organize construction and separate accounting, but cannot independently exert production capacity and use efficiency. Unit project does not have the meaning of independent existence, it is a part of a single project.

Construction engineering, decoration engineering, electric lighting engineering and equipment installation engineering in industrial and civil construction engineering all belong to unit engineering. A unit project consists of several subprojects.

15, division project

Division project refers to the project divided according to different parts and structural forms of the project. For example, construction projects include earthwork, pile and foundation engineering, masonry engineering, concrete and reinforced concrete engineering, factory warehouse doors, special doors and wood structure engineering, metal structure engineering, roof and waterproof engineering and other sub-projects.

Division project is an integral part of unit project. A divisional project consists of several sub-projects.

16 subdivisional work

Sub-projects are projects divided according to different work types, component categories and materials used. For example, strip foundation, independent foundation, whole house foundation, equipment foundation, rectangular column, beam and slab, balcony, stairs, awning and overhangs in concrete and reinforced concrete subdivisional works all belong to subdivisional works.

Sub-project is the basic element of engineering quantity calculation and the basic unit of engineering project division, so engineering quantity is calculated according to sub-project.