Steel structure is the direction of future development. There are many people who can’t calculate the amount of civil engineering and steel structure. But if they don’t, they have to talk about that their wages can’t go up.Steel structure has always been separated from civil engineering. In the construction process of later steel structure and steel composite structure, the steel structure company installed it first, and then the general contract construction concrete was carried out. So the joint will be gradually similar, sometimes basically integrated together. Let’s talk about the calculation of steel structure, and the quotation can’t be talked about.

1

The most basic calculation is to look at the drawings

People in civil engineering are annoyed by the confusion of steel structure drawings, because the plane method is not used in it, and the drawing still retains the principle of previous civil engineering drawing, so as an old man, it is more customary to look at the steel structure detail (people before the 101 atlas is published). There are quite a lot of detail nodes of steel structure, but these changes really have a small impact on the calculation. The important thing is to grasp the direction well, and the node diagram of steel structure is alsoIt is quite scientific, which corresponds to the force of science.Many are repetitive or symmetrical.If you look at it carefully, you can see it.I will talk about the characteristics of the drawings below

2

Calculate the weight

Because the calculation of steel structure is basically based on tons (m2 for plates).Steel + steel is steel structure.And steel mostly refers to section steel. I will list the classification and calculation methods of section steel.And make an explanation.

3

Statistical summary

Haha, this kind of work should not be difficult. It is based on the list and classified and summarized. 

1、 Steel structure

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

    2 The steel structure design drawings shall be completed by the design unit with design qualification, and the content and depth of the design drawings shall meet the requirements for the preparation of steel structure construction details; the steel structure construction details (i.e. processing and manufacturing drawings) shall generally be completed by the processing unit with special steel structure design qualification, or other units with the qualification.

    Note: if the design contract does not specify the requirements for the design of steel structure construction details, the steel structure design content is only the steel structure design drawing.

3 Steel structure design drawing

1）Design Description: design basis, load data, project category, project overview, steel grade and quality grade (physical and mechanical properties and chemical composition requirements shall be put forward if necessary) and model, specification, weld quality grade, anti-corrosion and fire prevention measures of connecting parts;

2）The foundation plan and detailed drawing should express the detailed drawing of connecting structure between steel column and lower concrete member; 

   3）The layout plan of structure plan (including each floor and roof) shall indicate the positioning relationship, elevation, position and number of components (single line drawing can be arranged), node detail drawing, index number, etc.; if necessary, purlin, wall beam layout and key section shall be drawn; upper and lower chords and key sections of space grid shall be drawn;

4）Details of components and joints

a) The simple steel beam and column can be expressed by unified detailed drawing and tabulation method, indicating the steel grade, size, specification, stiffening rib method, connection node detail, construction and installation requirements.

b) For lattice beam, column and support, plane and section (elevation shall be added if necessary), positioning dimension, overall dimension, sub dimension and sub dimension shall be drawn, and the model and specification of single component, assembly node and connection details of other components shall be indicated.

4 Steel structure construction details

According to the steel structure design drawing, the enlarged drawing of each part of the structural component is prepared. The standard detail size, material requirements, processing accuracy, process flow requirements, weld quality grade, etc. should be numbered; and considering the transportation and installation capacity, determine the segment and assembly node of the component.

2、 Common terms

steel structure:

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

Features of steel structure:

Light weight and high strength;

Good plasticity and toughness;

Isotropic, stable performance;

Weldability;

It is not easy to leak;

Heat resistant but not fire resistant;

Poor corrosion resistance;

It is easy to manufacture and has short construction period.

plasticity:

The ability of material to absorb deformation energy under static load.With good plasticity, the structure will not break suddenly due to accidental overload under normal conditions, which can provide safety guarantee for people.

The purpose of structural design:

It is to ensure that the designed structure and structural components can meet various predetermined functional requirements and have appropriate reliability in the process of construction and work.

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

The characteristics of different structural forms should be considered in structural selection.

In the industrial workshop, when there is a large hanging load or a large range of moving load, it can be considered to abandon the portal frame and use the grid structure.In areas with high basic snow pressure, the roof curve should be conducive to snow sliding (snow load is not required to be considered beyond the tangent line of 50 degrees). For example, three center circular reticulated shell is used for limestone shed of cement plant, and the total snow load is released by nearly half compared with that of sloping roof.

Similar consideration should be given to areas with large rainfall.When the building allows, the layout of braces in the frame will be more economical than the frame with simple joints.In the buildings with large roof covering span, the suspension cable or cable membrane structure system whose members are mainly tensioned can be selected.

In the design of high-rise steel structures, steel-concrete composite structures are often used. In high-rise buildings with high seismic intensity or very irregular seismic intensity, the form of core tube and outer frame should not be selected simply for the sake of economy.It is better to select the surrounding huge SRC columns and the core is the supporting frame structure system.More than half of such high-rise buildings in China are the former, which is unfavorable to earthquake resistance.

Generally speaking, the stiffness should be uniform and the mechanical model should be clear. The influence range of large load or moving load should be limited as much as possible,The lateral bracing between columns should be evenly distributed. Its centroid should be close to the action line of the lateral force (wind and earthquake). Otherwise, the torsion of the structure should be considered. The anti side of the structure should have multiple lines of defense. For example, in a braced frame structure, the column should be able to bear at least 1 / 4 of the total horizontal force alone

Sometimes, the direction of load transfer can be adjusted to meet different requirements for the arrangement of secondary beams in the floor plan of frame structure.Generally, in order to reduce the cross-section, the secondary beam is arranged along the short direction, but this will increase the section of the main beam, reduce the clear height of the floor, and sometimes the side column on the top floor can not be used up. At this time, supporting the secondary beam on the shorter main beam can sacrifice the secondary beam to keep the main beam and column

3、 Component design is the first choice of materials

Q235 and Q345 are commonly used. Q345 can be selected when the strength is controlled; Q235 should be used when stability is controlled. Generally, single steel grade is used for main structure to facilitate engineering management. For economic consideration, welded composite sections of steel with different strength (flange Q345, web Q235) can be selected. In addition, Q235B or Q345B should be selected for welded structure.

4、 Node design

1.Welding: for the size and form of welding seam, the specification has mandatory provisions, which should be strictly observed. The selection of welding rod should adapt to the material of the connected metal. E43 corresponds to Q235, E50 corresponds to Q345. When Q235 is connected with Q345, E43 with low strength should be selected,The center of gravity of the weld should be close to the center of gravity of the connected components. Other details can be found in the specification on the weld structure

2.Bolt connection: riveting type, rarely used in construction engineering. Ordinary bolt has poor shear performance and can be used in secondary structure. High strength bolt is used more and more widely. Two strength grades of 8.8s and 10.9s are commonly used. According to the stress characteristics, the bearing type and friction type are divided. The calculation methods are different. The minimum specification of high-strength bolt is M12. The commonly used m16-m30 bolt is unstable,It should be used with caution.Self tapping screws are used for the secondary connection between plates and thin-walled steel sections. In Low-Rise wall panel houses, they are also commonly used for the connection of main structures. It is difficult to solve the problem of corrosion-resistant coating damage in the process of self tapping. 

3.Connecting plate: it is necessary to check the shear strength of the net section at the weakening of the bolt hole. The thickness of the connecting plate can be simply taken as the thickness of the beam web plus 4mm, so it is not necessary to check the shear strength except for the short beam or the beam with large concentrated load.This is actually the steel plate (usually) added to the two butt weldments

4.Beam web: the net section shear resistance of the web at the bolt hole should be checked and calculated. The bearing type high strength bolt connection also needs to check the local bearing of the hole wall

5.The joint design must consider the construction space for installing bolts, welding on site and the hoisting sequence of components.It is a common mistake for beginners that the components cannot be installed when they are transported to the site.In addition, workers should be able to locate and fix temporarily on site as easily as possible.

6.The process level of the manufacturer should also be considered in the joint design. For example, the cutting of the intersecting line of the steel pipe joint may need CNC machine tools to complete

5、 Drawing preparation

The steel structure design drawing is divided into two stages: design drawing and construction detail drawing. The design drawing is provided by the design unit. The construction detail drawing is usually prepared by the steel structure manufacturing company according to the design drawing, and sometimes it is prepared by the design unit.Due to the contradiction between the increase of steel structure projects and the lack of steel structure engineers in Design Institute in recent years, it is common for steel structure companies with design ability to participate in the preparation of design drawings.

1.a design chart:

It is the basis for the manufacturer to prepare the construction details. The depth and content shall be complete but not redundant,The design basis, load data (including earthquake action), technical data, material selection and material requirements, design requirements (including manufacturing and installation, weld quality inspection grade, coating and transportation, etc.), structural layout, component section selection and structure of main nodes of the structure shall be clearly stated, so as to facilitate the preparation of construction details and correctly reflect the designThe intention of the plan.The main materials should be listed.

2.Construction details:

It is also called processing drawing or lofting drawing, etc. the depth must be able to meet the requirements of direct manufacturing and processing in the workshop. Different component units must be separately expressed and attached with a detailed material list

6、 Weight calculation and explanation of steel members

The installation process of steel structure is different. You can look at the scheme more. It has an impact on our quotation, but it has little impact on my calculation, unless his scheme is to be demolished,

The weight calculation of steel structure mainly revolves around the density of iron, which is usually 7.86 

The density of iron is 7.8 g / cm3 – sometimes 7.85

In fact, the weight of a steel member is a matter of volume and density. The weight is expressed in T, which is the volume calculated in square meter * 7.86t/m3. This is the weight (weight, in reality, the weight is based on tons, and mechanics is in cattle). When expressed on drawings, most of the symbols are represented by the first letter of Chinese pinyin. See the table below, which is the list item,This is followed by the items incorporated.

Steel structure is made of steel plate, angle steel, channel steel, steel pipe and round steel, etc.Steel structure has the advantages of high material strength, light weight, safety and reliability, and simple fabrication.In housing construction, it is mainly used for factory buildings, high-rise buildings and large-span buildings.Common steel structure components include roof truss, purlin beam, column, support system, etc.

Component code: basic components of building structure, such as slab, beam, column, etc.There are many kinds and complicated layout. In order to make the diagram concise and clear, and to distinguish the components, it is convenient to construct, tabulate and consult. Each type of component is given code.Code of common components

Section steel

I-beam:

1、 I-section steel, also known as steel beam, is a kind of section steel with I-shaped section.Its specification is expressed in mm of waist height (H) × leg width (b) × waist thickness (d). For example, “I 160 * 88 * 6″ means I-beam with waist height of 160 mm, leg width of 88 mm and waist thickness of 6 mm.

2、 I-beam is widely used in various building structures, bridges, vehicles, supports, machinery, etc.

3、 Type and specification I-beam is divided into ordinary I-beam and light-duty I-beam, and the specification of hot-rolled ordinary I-beam is 10-63 mm.The specification of hot-rolled common I-beam is 12-55 mm.The specification of I-beam can also be expressed by model. The model indicates the centimeter of waist height, such as 16 mm.For I-beams with the same waist height, if there are several different leg width and waist thickness, a B C should be added on the right side of the model to distinguish them, such as 32a ා 32b ා 32c #. 

4、 The main producing areas in China are Baotou Steel, Laigang, WISCO, Maanshan Iron and Steel Co.

The calculation method can only look up the table or tool. Note that it is different from H-beam because it is a finished product. It is OK to find out how many times a meter, and it is not necessary to make holes

H-beam

It is a kind of economic section high-efficiency profile with more optimized cross-section area distribution and more reasonable strength weight ratio. It is named because its section is the same as the English letter “H”.H-beam has been widely used because of its strong bending resistance, simple construction, cost saving and light structure.

Expression method of hot-rolled H-beam: H-beam is divided into wide flange H-beam (HK), narrow flange H-beam (Hz) and H-beam pile (HU).

The width of the web plate is 200 mm, and the width of the flange plate is 200 mm. For example, the width of the flange plate is 200 mm and the width of the flange plate is 200 mm.

The advantages of hot rolled H-beam are as follows

H-beam is a new type of economic building steel.

Compared with ordinary I-beam, H-beam has the advantages of large section modulus, light weight and metal saving, which can reduce the building structure by 30-40%;

Because the inner and outer sides of the legs are parallel and the leg ends are right angles, the welding and riveting work can be saved by 25%.

It is commonly used in large buildings (such as factory buildings, high-rise buildings, etc.) with large bearing capacity and good cross-section stability, as well as bridges, ships, lifting and transportation machinery, equipment foundation, support, foundation pile, etc.

H-beam steel is mainly used in industrial plants, civil buildings, municipal engineering, oil platforms, bridges, flat car girders, electric power supports of electrified railways, steel bridges along the railway, etc. it is very suitable for container, mobile house, all kinds of depots, box trains, electrical supports, stadiums and villas.

Hot rolled H-beam has excellent mechanical properties and excellent service performance by reasonably distributing the aspect ratio of cross-section size according to different uses.

Production process of welded H-beam

Steel plate — Automatic slitting — assembly — automatic submerged arc welding — flaw detection — flange correction — Web correction — end face processing — sand blasting and rust removal — spray painting.

The cutting, assembling and welding of automatic submerged arc welding production line are all controlled by microcomputer to ensure the dimensional accuracy of the produced H-beam and the weld quality meets the national standard.

Steel structure building, simple and light structure, expands the internal space of the building, saves steel, and has short installation period. The roof and wall are made of color profiled steel plate, which makes the building more modern.

The welding quality is higher. This is different from I-beam, so we can calculate it

Weight of H-beam (2 * b * T2 + h * T1-2 * T1 * T2) * 7.85 * L / 1000000

Surface area of H-beam (4 * B-2 * T1 + 2 * h) * L / 1000

1、 Classification of steel plate (including strip steel)

1Classification by thickness:

(1) Sheet

(2) Medium plate

(3) Thick plate

(4) Extra heavy plate

2Classification by production method:

(1) Hot rolled steel plate

(2) Cold rolled steel sheet

3Classification according to surface characteristics:

(1) Galvanized sheet (hot dip galvanized sheet, electro galvanized sheet)

(2) Tinplate

(3) Composite steel plate

(4) Color coated steel plate

4Classification by use:

(1) Bridge steel plate

(2) Boiler steel plate

(3) Shipbuilding steel plate

(4) Armor plate

(5) Automobile steel plate

(6) Roof steel plate 

(7) Structural steel plate

(8) Electrical steel plate (silicon steel sheet)

(9) Spring leaf

(10) Others

2、 Common Japanese grades of steel plates for general and mechanical structures

1The common structural steel of Japanese steel (JIS Series) is mainly composed of three parts, the first part is the material,

For example, s (steel) stands for steel, f (ferrum) stands for iron; the second part represents different shapes, types and uses, such as P (plate) for plate, t (tube) for tube, K (kogu) for tool; the third part represents characteristic number, which is generally the minimum tensile strength. 

For example: SS400 – the first s stands for steel, the second s stands for structure, 400 is the lower limit tensile strength of 400MPa, and the whole represents ordinary structural steel with tensile strength of 400MPa.

2SPHC — the first s is the abbreviation of steel steel, P is the abbreviation of plate plate, h is the abbreviation of hot heat, and C is the abbreviation of commercial commercial. Generally speaking, hot rolled steel plate and strip are used.

3SPHD — hot rolled steel plate and strip for stamping.

4Sphe — hot rolled steel plate and strip for deep drawing.

5SPCC – cold rolled carbon steel sheet and strip, equivalent to q195-215a in China.The third letter C stands for cold cold.To ensure the tensile test, add t at the end of the grade to spcct.

6SPCD cold rolled carbon steel sheet and strip for stamping, equivalent to China 08Al (13237) high quality carbon structural steel.

7Spce — cold rolled carbon steel sheet and strip for deep drawing, equivalent to China 08Al (5213) deep drawing steel.When non timeliness is required, add n at the end of the grade to be spcen.Quenching and tempering code of cold rolled carbon steel sheet and strip: annealed state is a, standard quenching and tempering is s, 1 / 8 hard is 

81 / 4 hard is 4, 1 / 2 hard is 2, hard is 1.Surface processing code: D for matte finish rolling and B for bright finishing rolling.For example, spcc-sd stands for standard quenched and tempered, matt finish rolled carbon sheet in general.Another example is spcct-sb stands for standard quenching and tempering, bright processing, which requires to ensure the mechanical properties of cold-rolled carbon sheet. 

9The steel grade of JIS mechanical structure is expressed by S + carbon content + letter code (C, CK), in which the carbon content is represented by the middle value × 100, and the letter C is the carbon and K is the steel for carburizing.For example, the carbon content of s20c is 0.18-0.23%.

3、 Designation of silicon steel sheet grades in China and Japan

1Chinese brand indication method:

(1) Cold rolled non oriented silicon steel strip (sheet): DW + iron loss value (at frequency of 50 Hz, sinusoidal magnetic induction peak value is 1.5T unit weight iron loss value.)100 times the thickness value. 

For example, dw470-50 represents the cold-rolled non oriented silicon steel with core loss of 4.7w/kg and thickness of 0.5mm, and the new model is 50W470. 

(2) Expression method of cold rolled oriented silicon steel strip (sheet): DQ + iron loss value (core loss value per unit weight of magnetic induction peak value of 1.7t at frequency of 50 Hz and sinusoidal waveform)100 times the thickness value.Sometimes G is added after the core loss to indicate high magnetic induction.

 For example, dq133-30 stands for cold-rolled oriented silicon steel strip (sheet) with iron loss of 1.33 and thickness of 0.3mm, and the new model is 30q133.

(3) Hot rolled silicon steel plate hot rolled silicon steel plate is represented by Dr, which is divided into low silicon steel (silicon content ≤ 2.8%) and high silicon steel (silicon content > 2.8%). 

Expression method: 100 times of Dr + iron loss value (core loss per unit weight when the maximum value of magnetic induction intensity is 1.5T after repeated magnetization with 50 Hz and sinusoidal variation) + 100 times of thickness value. 

For example, dr510-50 represents hot-rolled silicon steel plate with iron loss of 5.1 and thickness of 0.5mm.The grade of hot-rolled silicon steel sheet for household appliances is expressed by JDR + iron loss + thickness value, such as jdr540-50.

2Japanese brand indication method:

(1) The cold rolled non oriented silicon steel strip is composed of nominal thickness (increased by 100 times) + code a + guaranteed value of core loss (the value of core loss increased by 100 times when the frequency is 50 Hz and the maximum flux density is 1.5 T). 

For example, 50a470 refers to the cold-rolled non oriented silicon steel strip with thickness of 0.5mm and iron loss guarantee value of ≤ 4.7.

(2) Cold rolled grain oriented silicon steel strip is composed of nominal thickness (increased by 100 times) + code G: common material, P: high oriented material + guaranteed value of core loss (the value of core loss increased by 100 times when the frequency is 50 Hz and the maximum flux density is 1.7 T). 

For example, 30g130 means cold-rolled oriented silicon steel strip with thickness of 0.3mm and core loss guarantee value of ≤ 1.3.

4、 Tinplate and hot dip galvanized sheet:

Steel plate, because most of the components in the component are steel plates, whether they are triangular or not, they should be regarded as external quadrilateral. They are all quadrilateral. Of course, the weight of steel plate is as follows: a * b * t * 7.85/1000000000, a B is the length and width of steel plate, t is the thickness of steel plate