4 precautions for the calculation of steel structure engineering quantities

1. Drawings

According to the drawing catalog, clean and check the number of drawings to check whether there are any omissions.

2. Construction drawings

1. Design general description

1.1 Building area, structural form, column spacing, span, structural layout;

1.2 Scope of quantity calculation: for structure, roof, wall, doors and windows, etc., clear the scope of bidding and quotation;

1.3 Material selection, specifications, models, technical requirements;

1.4 Paint or coating requirements and fire rating of steel structure.

2. Floor plan, elevation view, section view:

It can count the engineering quantity of doors and windows, indoor and outdoor steel ladders, roof color boards, lighting panels, wall color boards, roof ventilators, canopies, downspouts, edge flashing parts, gutters, etc. When counting, the material, specification and model of each material should be indicated.

3. Structural construction drawings

1. General description of structural design

1.1 Material: the material corresponding to the components of each part (steel column, beam, purlin, support, etc.), such as Q235, Q345, strength level requirements of high-strength bolts, etc.;

1.2 welding quality requirements: weld quality level, non-destructive

testing requirements, such as splicing weld quality level should reach the first level, require 100% flaw detection, secondary weld 20% flaw detection, involving the calculation of non-destructive testing costs.

1.3 Rust removal requirements: manual and power tools rust removal (St), spray or ejection rust removal (Sa). Different rust removal grades, rust removal costs are different.

1.4 Paint (painting) requirements: paint type, number of brushes, paint film thickness, fire rating, fire resistance limit of each part.

2. Floor plan, elevation view, section view, node detail:

2.1 The quantities can be calculated sequentially as follows:

2.1.1 Embedded iron parts: including embedded positioning plates, embedded bolts, nuts;

2.1.2 Steel columns, windproof columns, steel beams, crane beams;

2.1.3 Roof support, tie pole, intercolumn support, canopy skeleton;

2.1.4 Roof purlins, wall purlins, roof and wall purlins of the corner brace, tie rod;

2.1.5 In the calculation process, pay attention to calculate the engineering quantity of the connecting parts of the crane beam and the column, the cushion plate, the

roof and wall purlins, the connecting plate between the corner brace and the steel column and the beam, the steel casing of the diagonal tie rod, etc., and pay attention to the number of high-strength bolts.

2.2 If the drawing lists the material table, check whether the size, specification and quantity of the parts in the table are

accurate according to the part numbers listed in the material table, and whether there are undercalculations, omissions or miscalculations.

2.3 Pay attention to whether there are design changes and modifications, supplementary explanations, Q&A, etc.

4. Matters that should be paid attention to in the calculation process

1. About the format of quantity calculation

1.1 The weight unit of the steel structure is kg, the unit of area is m2, and the length unit is m, and the calculation results are reserved for one decimal place.

1.2 When calculating the weight of the component, the parts of the component can be numbered from bottom to top and left to right, and calculated in this order.

1.3 Format of the formula:

1.3.1 Plate: specification× length× width× quantity

For example, -6×500×300×5, which means that the plate thickness of the part is δ=6mm, the length of the plate is 500mm, the width is 300mm, and the quantity is 5 pieces.

The weight calculation formula is: 6×0.5×0.3×7.85×5=35.3kg

1.3.2 Profiles: specification, length× quantity× specific gravity

For example, L50×5, L=3500mm×5×3.77, means that the limb width of 50mm equilateral angle steel, the length is 3500mm, the number is 5 pieces, and the specific gravity is 3.77kg/m.

The weight calculation formula is: 3.5×5×3.77=66.0kg

2. Points to note when calculating the size

2.1 Pay attention to the elevation value of indoor and outdoor and steel column bottom plate, whether it is ±0.00 or other elevation value. When calculating the length (or height) with elevation values, special care should be taken not to calculate them all at ± 0.00.

2.2 Regarding the calculation of the height (

or length) of the stiffener plate, purlin corner brace and parapet wall eaves bracket corresponding to the variable H-section members (beams and columns), it can be calculated based on the average H-section height of the beam and column.

2.3 The length of the roof purlin, are calculated according to the general length, without deducting the gap between the purlins, in addition, pay attention to the length of the purlins occupied by the roof beam at the gable, for example, the axis represents the center line of the roof beam, then: the length of the purlin = axis length + roof beam width.

2.4 For the calculation of wall purlins, attention should be paid to whether the door pillars and door beams are double purlins, and whether there are double purlins in other parts.

2.5 The length of the tie rod is calculated according to the corresponding purlin spacing plus 50mm at each end, and the length of each tie rod is increased by 100mm.

2.6 Calculation of edge flashing parts

2.6.1 Calculation range: roof ridge cover board, flashboard at the interface between gutter and roof panel and parapet wall, flashboard at the interface between gable wall and roof panel, top flashboard at the upper part of the parapet wall, edge panel at the corner of the wall, edge board around doors and windows, flashboard at the junction of wall

panel and brick wall, flashboard at the junction of wall surface and canopy, edge board around canopy. If it is a double-layer board, the edge parts at each interface of the roof inner panel and the wall inner panel are also calculated.

2.6.2 About the width of the flanging flashboard: Under normal circumstances, the unfolded width of the flanging flap can be calculated by 300~400mm, and the unfolding width of the parapet wall topping and ridge cover plate can be calculated by 500~700mm. In practice, it can be calculated according to the corresponding contact detail of the design.

2.7 The web of variable section beams and columns shall be calculated according to the net weight when bidding, subcontracting settlement and cost calculation, and shall be calculated according to the external rectangle when handling settlement with Party A. The various connection plates are calculated as an external rectangle.

3. The part that cannot be counted repeatedly

3.1 High-strength bolts: the connection between column beams and the connection between crane beams are common to two components, and one member cannot be calculated once.

3.2 Roof support, tie rod, inter-column support: Some construction drawings indicate the partial arrangement of roof support on the inter-column support drawing, and it has been calculated when calculating the roof support, it should not be calculated, in this case, the roof support and wall support drawings should be compared.

4. Other matters that should be noted

4.1 When calculating the specific gravity of profiles, especially H-beams and steel pipes, do not forget to reduce the thickness that should be reduced. For example, when calculating the specific gravity of a steel pipe, do not calculate it as a round bar, and subtract the area occupied by the inner diameter.

4.2 When checking the proportion of materials on the hardware manual or other materials, be sure to read clearly and do not check wrong.

4.3 When calculating the specific gravity of C-type purlins, it can be calculated according to the unfolded area.

4.4 The skeleton of hollow sunlight panels, aluminum-plastic panels and other decorative surface materials, etc., should not be missed.

4.5 All calculation processes require careful care, must not be careless, under normal circumstances, two calculations should be checked. The saying "if you lose a little, you will lose a thousand miles", you should remember it. The consequences of poor calculation accuracy or errors can be severe. In addition, we must not be ashamed to ask questions and be humble and studious; Frequently go to the front line of the project, understand and be familiar with various construction processes and processes, deepen the impression, and lay a foundation for better pre-settlement work.