Learn to make steel structure budget step by step

2018-09-25 10:57:26 Click:

Steel structure is the future direction of development, civil calculation will not steel structure calculation of a large number of people, but in the future if not, we have to talk about their wages are not going up. Steel structure has always been separated from civil engineering. Later, steel structure and steel composite structure in the construction process, are first installed by the steel structure company and then the total contract construction of concrete, so that the joint will be slowly similar, sometimes basically merged together, the following said to do the calculation of steel structure, quotation can not be said.

1. The basic calculation is to look at the drawings, civil construction people are annoyed with the steel composition paper is too messy, because the leveling is not used on it, the design also retains the previous principles of civil engineering drawing, so as the elderly look more accustomed to (101 drawings before the collection of people), the details of the steel structure knots quite a lot, but these changes are really in the calculation. When the impact is quite small, the important is to grasp the direction of a good, steel structure node diagram is quite scientific, and scientific forces are corresponding. Many of them are repetitive or symmetrical. Seriously, you will see. For the characteristics of the drawings, I will talk about them below.

2. Calculate the weight, because the calculation of steel structure is basically based on tons (plate M2). Steel and steel are steel structures. And steel multi finger steel, for the classification of steel section calculation method, I will list one by one. And make explanations.

3. Statistical summary, ha ha, this should be not difficult, with the list as the basic, classified and summarized.

I. steel structure

1 the design drawing of steel structure is divided into two stages: steel structure design and steel structure construction detail.

2. The steel structure design drawing shall be completed by the design qualified design unit, and the content and depth of the design drawing shall meet the requirements of the preparation of the steel structure construction detailed drawing; the steel structure construction detailed drawing (i.e. the processing drawing) shall generally be completed by the processing and manufacturing unit with the steel structure special design qualifications, or by other qualifications. Unit completed.

Note: If the design contract does not specify the detailed drawing of the steel structure, the design of the steel structure is only the design of the steel structure.

3 steel structure design

1) Design specifications: design basis, load data, project category, general situation of the project, steel grades and quality grades used (physical, mechanical and chemical composition requirements, if necessary) and connector type, specifications, weld quality grade, anti-corrosion and fire prevention measures;

2) the foundation plane and detailed drawing should express the detailed structure of the connecting structure between the steel column and the lower concrete component.

3) The structural plan (including floors and roofs) should indicate the location relationship, elevation, the position and number of components (which can be drawn by single line), the index number of node detailed drawings, and so on; if necessary, purlins, wallboard layout drawings and key section drawings should be drawn; space truss should draw the upper, lower chord and key section drawings;

4) Detailed drawings of members and joints a) Simple steel beams and columns can be represented by unified detailed drawings and tabulations, indicating the steel grades, sizes, specifications, stiffening ribs, detailed drawings of joints, construction and installation requirements. B) Lattice beams, columns and supports shall be drawn in flat and cross-sectional (with elevations if necessary), detailed drawings of connection with positioning dimensions, total dimensions, sub-sizes, sub-sizes, single member models and specifications, assembly joints and other components. 4 construction details of steel structure

According to the steel structure design drawing, the enlarged drawing of each part of the structural component is compiled, and the standard detail size, material requirement, machining precision, process flow requirement, weld quality grade and so on, the parts should be numbered.

Commonly used terminology

Steel structure: It is composed of steel plate, section steel, cold-formed thin-walled section steel, etc. through welding or bolt connection.

Characteristics of steel structure: light weight and high strength; good plasticity and toughness; isotropy, stable performance; weldability; not easy to leakage; heat but not fire resistance; poor corrosion resistance; easy to manufacture, short construction period.

Plasticity: the ability of materials to absorb deformation energy when subjected to static loads. Good plasticity, will make the structure in general not due to accidental overloading and sudden rupture, to give people security.

The purpose of structural design is to ensure that the designed structure and structural components can meet various predetermined functional requirements and have appropriate reliability during construction and work.

Steel structure usually has frame, plane truss, grid (shell), cable membrane, light steel, tower mast and other structural forms.

In the selection of structures, the characteristics of different structural forms should be considered. When there are large suspended loads or large-scale moving loads in industrial buildings, the portal frame can be considered to be abandoned and the grid frame can be adopted. In areas with high snow pressure, the roof curve should be conducive to snow fall (no snow load is required outside the tangent of 50 degrees). For example, the limestone silo in a cement plant uses a three-core reticulated shell, which releases nearly half of the total snow load compared with the sloping roof. The area with heavy rainfall is similar. When buildings permit, bracing in frames is more economical than simply jointed frames. In buildings with large roof coverage span, suspension or cable-membrane structures with tensile members can be selected. In high-rise steel structure design, steel-concrete composite structure is often used. In high-rise buildings with high or irregular seismic intensity, it is not necessary to choose the form of core tube and outer frame which is unfavorable to earthquake resistance simply for the sake of economy. It is advisable to choose the giant SRC column around the core, and the core is the structural system supporting the frame. More than half of the top class in China are the former, which are unfavorable to earthquake resistance.

Generally speaking, the stiffness should be uniform. The mechanical model should be clear. The influence range of large load or moving load should be limited as far as possible, so that it can be transmitted to the foundation by the most direct line. The distribution of lateral braces between columns should be uniform. The shape center should be as close to the lateral force (wind). Otherwise, the torsion of the structure should be considered. The lateral resistance of the structure should have multiple lines of defense. For example, a braced frame structure, the column should be able to withstand at least one fourth of the total horizontal force alone.

The layout of plane secondary beams of frame structures can sometimes be adjusted to meet different requirements. In order to reduce the cross-section along the short direction of the secondary beam, but this will increase the cross-section of the main beam, reduce the floor height, the top side columns are sometimes overwhelming, at this time to support the secondary beam in the shorter main beam can sacrifice the secondary beam to retain the main beam and column.

First of all, component design is material selection.

Q235 and Q345 are commonly used. When the strength is controlled, Q345 can be selected; when the stability is controlled, Q235 can be used. Usually the main structure uses a single steel for engineering management. Economic considerations can also be selected for different strength of steel welding combination section (flange Q345, web Q235). In addition, the welding structure should choose Q235B or Q345. 5B.

Node design

1. Welding: The size and form of the welding seam are mandatory and should be strictly observed. The selection of electrode should be adapted to the material of the joined metal. When E43 corresponds to Q235, E50 corresponds to Q345. Q235 and Q345, E43 with low strength should be chosen instead of E50. Welding seam should not be enlarged arbitrarily in the design of welding. The detail of the connection is close to the center of gravity. Other details can be found in the specification of weld structure.

2. Bolted joints: riveted joints are seldom used in construction. Common bolts have poor shear resistance and can be used in secondary structures. High-strength bolts are used more and more widely. The performance of bolts with super large M16~M30. is unstable and should be used with caution. Self-tapping screw is used for secondary connection between sheet metal and thin-walled steel. It is also used for connection of main structure in Low-Rise wallboard dwelling houses. It is difficult to solve the problem of corrosion protection layer damage in the process of self-tapping.

3. Connecting slab: It is necessary to check the shear resistance of the net section at the weakening of the bolt hole. The thickness of the connecting slab can be simply taken as the thickness of the beam webs plus 4 mm, and the shear resistance of the short beams or beams with large concentrated load is often not checked. This is actually what kind of steel plate is added on the two butt welds (usually).

4. Beam webs: The net section shear strength of the webs at the bolt holes should be checked. The local pressure on the wall of the bolt holes should also be checked.

5. node design must consider installation bolts, on-site welding and other construction space and lifting sequence of components. It is a beginner's mistake to send parts to the site without installation. In addition, workers should be allowed to carry out on-site positioning and temporary fixation as far as possible.

6. Joint design should also take into account the manufacturing process level. For example, the cut of the intersecting line of steel pipe joints may require CNC machine tools and other equipment to complete.

Drawing up

The steel structure design drawings are divided into two stages: design drawings and detailed construction drawings. The design drawings are provided by the design unit. The detailed construction drawings are usually compiled by the steel structure manufacturing company according to the design drawings, and sometimes by the design unit. Due to the contradiction between the increasing number of steel structure projects and the lack of steel structure engineers in the Design Institute in recent years, it is common for design-capable steel structure companies to participate in drawing up design drawings.

1. Design drawings: Provides the basis for the preparation of detailed construction drawings by the manufacturer. Depth and contents should be complete but not redundant. In the design drawings, the design basis, load data (including seismic action), technical data, material selection and material requirements, design requirements (including manufacturing and installation, weld quality inspection, grade, coating and so on) should be considered. Transportation, structural layout, member section selection and structure of the main nodes should be clearly stated in order to facilitate the smooth compilation of detailed construction drawings, and can correctly reflect the design intent. The main materials should be listed in a list.

2. Detailed construction drawings: also known as processing drawings or lofting drawings, etc. Depth must be able to meet the direct manufacturing of the workshop. Another component unit that is not identical must be separately drawn and expressed, and should be accompanied by a detailed list of materials.

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