Selection of columns for an industrial building. Reinforced concrete columns

In one-story industrial buildings, prefabricated reinforced concrete columns use solid rectangular sections (Fig. 53, a, b) and through two-branched (Fig. 53, c). In buildings equipped with overhead cranes, the columns have consoles for supporting crane beams on them, on which rails are laid to move the crane. Unified columns have a height that is a multiple of the module 600 mm. The design height of the column (H) is calculated from the level of the finished floor of the room, i.e. from the mark 0, 000 to the top of the column, excluding its lower end 900-1350 mm long, which is embedded in the foundation.

Rice. 53. Types of prefabricated reinforced concrete single-story columns industrial buildings: a - for craneless buildings; b-crane of rectangular section; c - crane two-branch for middle rows

The part of the column, located above the consoles, is called over-crane, below - under-crane. The overhead part of the column, which supports the elements of the coating, is called the overhead column. In two-branch columns, the over-column is made from one branch, as a result of which ledges are created to protect the crane beams. The upper end of the column has a steel embedded sheet with anchor bolts for fastening the load-bearing elements of the coating. Steel embedded parts are also provided in the places of installation of crane beams and ties and, in addition, in the side planes of the extreme columns (for fixing walls).

To align the position of the columns during their installation, risks are provided in the form of vertical grooves of a triangular profile. They are applied on the four faces of the columns (top and bottom), as well as on the side faces of the consoles of the columns.

The columns are made of concrete grades 200, 300 and 400, the working reinforcement is made of A-Sh class steel.

The half-timbered (auxiliary frame) columns arrange end half-timbered and half-timbered longitudinal walls of one-story industrial buildings with a length wall panels 6 and 12 m.

The columns rely on the load from the wind and the mass of the panel walls. install columns on independent foundations. The outer face of the columns is located in the plane inner surface walls.

The columns are made of concrete of grades 200-400, the working reinforcement is made of steel of class A-Sh.

26. Calculation and design of solid columns

The bending moments and transverse forces in the sections of the column are determined as in a cantilever beam loaded with an external load and reaction Re. Usually, 4 sections along the length of the column are calculated.

The sections of the columns are calculated taking into account the influence of the buckling (if λ> 34-12 * Mmin / Mmax, it is necessary to take into account the buckling) on ​​the value of the eccentricity of the longitudinal force

ea - random eccentricity

ea-MAX ( 20 mm

ρmin=5Nsd/(fyd*b*h) As1= As2=(ά*fcd*bw*d)/fyd * (άm,1- άn*(1-άn/2))/(1-δ)

άm,1= M sd /(ά*f cd *b w *d 2) - relative moment δ=c/d

άn= N sd /(ά*f cd *b w *d) - relative value of the longitudinal force

I check the columns from the plane of the transverse frame for stability as compressed elements. Columns are checked for forces arising during transportation and installation.

Short column consoles rely on the action of the support pressure from the crane beams

V rd , ct =*b w *d<=V rd , ct , max =0,5*b w *d*f cd *ϒ

The sectional area of ​​the longitudinal reinforcement of the console is determined by the bending moment at the edge of the column, increased by 25%.

A s 1 \u003d 1.25 * M / ((f yd * (d-c 2))

Column design:

Concrete not lower than C12/15, for heavily loaded-C20/25

Types of columns of one-story industrial buildings. Assignment of embedded parts.

Reinforced concrete and steel columns are used to construct the frames of one-story industrial buildings.

Reinforced concrete columns of one-story industrial buildings (Fig. 26) come with and without consoles (if there are no overhead cranes). According to their location in the plan, they are divided into columns of middle and extreme rows.

Given the dependence on the cross section of the column, there are rectangular, tee profile and two-branch. The dimensions of the cross section depend on the acting loads. The following unified column section sizes are used: 400x400,

Rice. 25. Foundations of one-story industrial buildings a) types of foundation beams; b), c) details of the foundations of the extreme row of columns; 1-sand; 2 - crushed stone preparation; 3 - Asphalt or concrete pavement (blind area); 4-waterproofing; 5-column; 6-slag or coarse sand; 7-reinforced concrete columns; 8 foundation beam.

Rice. 26. The main types of reinforced concrete columns of one-story industrial buildings. a) rectangular section for a building without overhead cranes at a step of 6m; b) the same, with a step of 12 m; c) two-branch for buildings without overhead cranes; d) rectangular section for cranes with overhead cranes; e) the same, I-section; f) two-branch for buildings with overhead cranes; g) general view of the column; 1 - embedded part for fastening the supporting structure of the coating; 2,3 - the same, crane beam; 4 - the same, wall panels.

Rice. 27. Main types of steel columns

a) constant section, b), d) variable section, e) separate

600x600, 400x800, 500x500, 500x600, 500x800 mm - for rectangular; 400x600 and 800x800 mm - for tee and 400x1000, 500x1000, 500x1300, 500x1400, 500x500, 600x1400, 600x1900 and 600x2400 mm - for two-branch. Columns come in several parts that are assembled at the construction site.

Columns with consoles consist of over-crane and under-crane branches. The cross-section of crane branches is most often square or rectangular: 400x400 or 500x500mm. For the manufacture of columns, concrete of classes B15, B40 and reinforcement of various classes are used.

The length of the columns is taken taking into account the height of the workshop and the depth of their embedding in the foundation, which should be: for columns of rectangular section without overhead cranes - 750 mm , for columns of rectangular and I-section with overhead cranes - 850mm; for two-branch columns-900-1200 mm.

Embedded parts are provided in the columns (Fig. 2b, g):

1 - for fastening the supporting structures of the coating (steel sheet welded to special fittings); 2 - for fastening crane beams from overturning under the action of braking forces; 3 - for fastening crane beams from displacement (steel sheet with four M16 bolts); 4 - for fastening wall panels (63x5, welded to the frame reinforcement before concreting the columns).

In addition to the base columns, half-timbered columns are used for the construction of half-timbered houses. They are installed along the building with a step of extreme columns of 12 m and a size of wall panels of 6 m, as well as at the ends of buildings.

Steel columns of one-story buildings can have a section that is constant in height and variable. In turn, columns with a variable section come with a crane part of a solid and through section (Fig. 27). Through columns are divided into columns with branches connected by ties, and separate columns, which consist of independently operating tent and crane branches. Columns of constant section are used when using cranes with a lifting capacity of up to 20 tons and a building height of up to 9.6 m.

In cases where the columns mainly work on central compression, solid section columns are used. For the manufacture of solid columns, a wide-shelf rolled or welded I-beam is used, and for through columns, I-beams, channels and bushings are also used.

Separate columns are arranged in buildings with heavy overhead cranes (125 tons or more). Steel bases (shoes) are provided at the bottom of the columns to interface with the foundations. The bases are fixed to the foundations with anchor bolts laid in the foundation during their manufacture. The lower supporting part of the column, together with the base, is covered with a layer of concrete.

Types of columns of one-story industrial buildings. Assignment of embedded parts. - concept and types. Classification and features of the category "Types of columns of one-story industrial buildings. Appointment of embedded parts." 2017, 2018.

The columns in the frame system perceive vertical and horizontal permanent and temporary loads. For mass industrial construction, standard designs of prefabricated reinforced concrete columns for buildings with supporting overhead cranes and for craneless buildings have been developed.

Reinforced concrete columns for buildings with overhead cranes have consoles for supporting crane beams. For craneless buildings, columns without consoles are used.

By location in the building system, the columns are divided into extreme (located at the outer longitudinal walls), middle and end (located at the outer transverse (end) walls).

For craneless buildings with a height of 3 to 14.4 m, columns of constant section have been developed (Fig. 7). The dimensions of the column section depend on the load and length of the columns, their pitch and location (in the outer or middle rows) and can be square (300x300, 400x400 mm) or rectangular (from 500x400 to 800x400 mm). They are buried in the foundations by 750 - 850 mm.

Rice. 7. Types of reinforced concrete columns for craneless buildings

For buildings with supporting overhead cranes of light, medium and heavy duty and with a lifting capacity of up to 300 kN, columns of variable section with a height of 8.4 to 14.4 m have been developed (Fig. 8), and for buildings with cranes with a lifting capacity of up to 500 kN - two-branch columns with a height of 10.8 to 18 m (Fig. 9).

The dimensions of columns of variable section in the crane section range from 400x600 to 400x900 mm, in the overhead section - 400x280 and 400x600 mm. Two-branch columns have dimensions in the crane section of 500x1400 and 500x1900, and individual branches - 500x200 and 500x300 mm.

Rice. 8. Types of solid reinforced concrete columns for buildings with

overhead cranes

Rice. 9. Types of two-branch reinforced concrete columns for buildings

with overhead cranes

In buildings with three or more cranes in the span, for the safety of personnel servicing cranes and crane runways, through galleries are provided along the runways at the level of the top of the runway beams with a size of 0.4x2.2 m (Fig. 10).

Rice. 10. Two-branch reinforced concrete columns

with passages at the level of crane tracks

Reinforced concrete columns have steel embedded elements for fastening truss structures, crane beams, wall panels (in the outermost columns) and vertical ties (in the tie columns). Anchor bolts are passed through the steel sheets in the places where the truss structures and crane beams are supported.

In buildings with sub-rafter structures, the length of the columns is taken 600 mm less (see Fig. 8,9,10).

half-timbered columns

In addition to the main columns, the buildings provide half-timbered columns installed at the ends of the buildings and between the main columns of the extreme longitudinal rows at a step of 12 m and a wall panel length of 6 m. They are designed to absorb wind forces and the mass of the walls.

Half-timbered columns are hinged to the foundation by welding the embedded parts of the column and the base sheet installed on top of the foundation strictly along the axes (node ​​2, Fig. 11). Fachwerk columns are attached to the roof structures using a leaf hinge (node ​​1, Fig. 11). Such a connection ensures the transfer of wind loads to the building frame and eliminates the vertical effects of the coating on the half-timbered columns.

Unified reinforced concrete columns for end fachwerk of two types (I and II) are used in the cases shown in table 1. In other cases, steel fachwerk columns are used. The structures of the columns are shown in fig. eleven.

Table 1

Columns of type I have a constant cross-section in height (h = 300 mm), which makes it possible to place their upper part in the gap between the end wall and the wall beam of the roof and fasten them to the upper chord of the beam using a leaf hinge (node ​​1, Fig. 11) .

Type II columns have a variable section in height (H in and H n, Fig. 11). The upper part of the column (Н в) has the same section as type I columns (h = 300mm) and is attached to the upper chord of the rafter beam in the same way as type I columns (node ​​1, Fig. 11).

A huge number of people, at the mention of such a word as "column", immediately recall the antique, decorative architectural monuments and buildings with wide carved columns supporting the ceiling. But in addition to such architectural objects that perform a decorative function, there are also reinforced concrete columns of industrial buildings that perform a supporting function to support the building frame.

Design features

Columns made of reinforced concrete mortar are rearranged vertical products with relatively small cross-sectional dimensions compared to their height or length.

Such building elements are mainly used to create braced or frame-type frames, and they are also used as load-distributing supports for other building elements:

• beams;
• Rigel;
• Runs.

Main properties and characteristics

Concrete concrete columns are products with the following set of properties:

• High resistance to aggressive environmental influences;
• Full compliance with the declared bearing capacity;
• Resistance to various seismic impacts;
• Impervious to moisture;
• Resistant to sub-zero temperatures.

The instruction for choosing a particular design provides a guideline for compliance with the following parameters:

1. Data obtained as a result of genealogical research;
2. Weather conditions and climatic zone in which the support will be operated;
3. The height of the building under construction or its number of storeys;
4. The functional purpose of the building, in the construction of which columns are involved.

The main and most important technical characteristic of reinforced concrete poles is precisely the bearing capacity. The higher this parameter is, the lower the column is located in the building. Products with the highest bearing capacity can be used in the construction of lower floors or basements.

For multi-storey buildings, columns are usually used, the design of which is endowed with several cantilever protrusions provided at a height of 2.5 and 3 meters. Marks of this type are the designation of the end of the floor, because it is on them that the floor beams are fixed for arranging the next level. Thus, the frame of high-rise buildings is formed.

Columns that are used to build buildings on one floor are taller and do not provide for the presence of ledges. Such supports can be used for the construction of industrial or agricultural premises.

Normative documents

Concrete products of this type are treated with a great degree of responsibility and impose the strictest requirements. Elements of this type are manufactured in full accordance with standardized documentation. Above them produce a huge number of different checks and tests for strength, reliability, rigidity and ability to resist cracking.

All basic requirements and standards for reinforced concrete supports are contained in the following documents:

• GOST 25628 of 1990 regulates the parameters of columns for the construction of one-story buildings;
• GOST 18979 of 1990 regulates the parameters of columns for the construction of multi-storey buildings;

Note! In these GOSTs, column piles are assigned the following designation "SK.40.2.5-1". This designation indicates that the length of such elements is 0.4 m, and their width is 0.2 m.

• The II 04-1 series regulates the parameters of products for creating a bonded frame;
• Series 1.423.1-3/88 specifies the parameters of the columns, which are the basis for the construction of one-story industrial premises;
• Series 1.823.1-2 specifies the characteristics of products for the construction of structures for agricultural purposes.

The price of such products belongs to the category of quite high and therefore it is important to ensure that the funds spent are justified. In terms of durability and strength, reinforced concrete columns have no analogues among the entire range of reinforced concrete products. It is these characteristics that determine the fact that the columns become the products around which the building is built.

What are columns made of?

The choice of material for the manufacture of such load-bearing structures is approached with particular care, because the main indicators of the finished product depend on it. Modern elements are made using solutions of the brand from M300 to M600 with a reinforced frame made using rigid rods and wire. Steel reinforcement can be stressed or non-stressed.

It is this steel hardening that will allow the column to have the necessary level of strength, durability and the ability to withstand enormous loads from floor slabs.

Do-it-yourself installation of reinforced concrete columns is carried out in specialized glasses or in monolithic foundations. Column foundations are products also made of reinforced concrete. Such elements have simply a huge margin of safety, which allows them to securely hold products of this type, excluding movement and tilt.

In the photo - the foundation for installation

Product classification

There are several types of classifications of such reinforced concrete structures according to various characteristics and features of the finished element.

Kinds

In appearance, such structures are divided into only two main groups:

1. With consoles - for the construction of buildings erected with overhead cranes:

• Rectangular - for buildings with a height of 9.6 m;
• Two-branch - for buildings with a height of more than 9.6 m;

Note! A product of this type consists of an over-crane part, on which the floor rests, and a crane part, which serves as a support for the beam and takes the load from the floor.

1. Consoleless - for the construction of buildings that are made without the use of overhead cranes.

The unified dimensions of reinforced concrete columns with consoles are also divided depending on the type of cross section:

• Rectangular - 400/400, 400/600, 400/800, 500/500, 500/600, 500/800(mm);
• With a two-branch section - 400/1000, 500/1000, 500/1300, 500/1400, 500/1550, 600/1400, 600/1900, 600/2400 (mm).

By section

According to the type of cross-section of the structure can be:

• round;
• Rectangular;
• Square.

By manufacturing technology

According to the method by which it is manufactured, the supporting structure can be:

• monolithic. Production is carried out directly at the construction site using the formwork method, in which the reinforcing frame is laid in advance;

• national team. Supports of this type are completely manufactured in industrial conditions at manufacturing plants. Transportation of such products to the building site is carried out using specialized equipment.

By position

Depending on the position of the column in the reinforced concrete structure of the frame of the building under construction, the products are divided into:

• Middle row columns;
• Columns of the extreme row;
• Front products.

The façade elements have an enlarged cantilever, which makes it possible for façade coverings to rest on it. The holes available in this console are intended for communication risers.

There are also facade products with long consoles for arranging balconies and loggias.

Some features of the calculation

Parameters such as length, presence of embedded elements, section, and bearing capacity of the column are determined by the calculation method at the stage of designing the structure. In a huge number of cases, it is prefabricated concrete products that are used, which have a length equal to two floors of the building being constructed.

The first thing that needs to be determined using the calculation is the cross-sectional area of ​​​​the concrete product, which will allow maintaining the uniformity of compression. This value is determined by the following formula:

A = F / Rb where:

• A is the cross-sectional area of ​​the product;
• F is the compressive force;
• Rb is the compressive strength of the concrete solution.

An example of the calculation of a reinforced concrete column:

F= 50 tons. having a compressive strength of 200 kgf / cm2.

A \u003d 50000/200 \u003d 250 cm2

The side of the square section will be equal to:

A=√250= 16 cm.

After the cross-sectional area is known, a calculation follows, taking into account the coefficients indicating the operating conditions, installation accuracy and other conditions that can increase the cross-sectional dimensions. You should also take into account eccentric compression, taking into account random eccentricity, and the flexibility of the created structure, which increases in proportion to the height of the product.

These calculations can be so cumbersome and complex that their production is often associated with a high probability of errors. And with the current capabilities of modern computer technology, it is simply not practical to make such calculations manually. Well, if it is necessary to determine the cross-sectional area of ​​​​the column in, so to speak, field conditions, then, of course, you will have to calculate manually.

In any case, the calculation should take into account not only the intrinsic strength of the column, but also the possibility of its interaction with the foundation and floors of the structure. Therefore, the calculated cross section should be increased at least from a constructive view of the reinforcement of the structure.

What to consider before buying

Before purchasing columns for the construction of a building or premises of an industrial or agricultural type, you should find a manufacturer from whom you can purchase good quality products at an affordable price.

In order to order and purchase a supporting reinforced concrete structure, you will need to provide the following data:

• A set of working drawings, according to which the necessary column was designed;
• Estimated number of storeys and height;
• Form;
• Cross section size;
• The presence of embedded parts;
• The location of the building plot in order to correctly calculate the cost of transporting the finished product.

Finally

Columns are an extremely important, durable and reliable product for the construction of tasks. When choosing such supports, one should be guided by the data indicated by GOST for reinforced concrete columns for industrial buildings, agricultural, one-story and multi-story. In addition to these regulatory documents, one should also rely on the calculation of an eccentrically compressed reinforced concrete column, which must certainly be present in the project.

Well, the installation of reinforced concrete supports will not be difficult, the main thing is that the product has all the declared characteristics, because the strength and reliability of the structure depend on them. And the video in this article will tell you even more about such an important element for construction as reinforced concrete columns.

To carry out the construction process of a private or multi-storey building, one cannot do without the use of reinforced concrete. What is reinforced concrete? Concrete is a building material that has a low strength index. This figure may vary depending on the method of concrete production, as well as the brand that was used for production. But, one way or another, it is still unsafe to use concrete due to the high level of fragility. That is why it is additionally reinforced. For this purpose, steel or another type of metal is most often used. It is desirable that it does not succumb to the formation of corrosion on the surface. On the basis of reinforced concrete, floor slabs can be made, as well as reinforced concrete columns, which are indispensable in private or multi-storey housing construction. Please note that you need to contact only professional manufacturing companies. Only in this case the construction will be safe. Consider the main features and advantages of using reinforced concrete columns, what technical characteristics they have.

The main advantages of using

The use of reinforced concrete is extensive due to the large number of positive aspects of operation. The main advantage is a high level of rigidity and resistance to various loads. Modern reinforced concrete columns are able to withstand the heavy weight of floor slabs. Also, the following factors can be attributed to the advantages of such columns:

• High level of rigidity and durability of application. Please note that such reinforced concrete columns can be used for more than 100 years. It should be noted that the level of strength does not decrease with the service life. That is why the building can be operated safely for a long time;
• Fire resistance. The two main building materials are concrete and steel. These materials are not subject to the combustion process, which also positively affects the operation of the house and the safety of living in it;
• Static and dynamic loads do not affect the use of reinforced concrete columns. Even a strong vibration of the earth will not contribute to the destruction or deformation of modern columns of this type.

But it is also worth noting some negative aspects of the application: the heavy weight of the columns (it is very difficult to transport them, install the columns as well), the thermal conductivity is quite high. But, as a rule, a high rate of columns does not greatly affect the living in the house.