Calculation of channel deflection/bending calculator online

A channel is a very popular product made of metal today. Its main distinguishing property is its U-shaped cross-section. The thickness of the finished product can be from 0.4 to 1.5 cm, and the height of the walls can be 5-40 cm.

Thin flange products are manufactured by processing flexible strip using special profile mills. Channels made from non-ferrous metals are obtained after processing the workpiece by pressing and extrusion, and steel channels are obtained using the technology of hot rolling of a metal billet on section mills.

Load calculation algorithm

• We find out the full value of the load on the profile included in the design and increase it by multiplying it by the reliability factor for the loads (we find it in the standards);
• We multiply the resulting product by the channel pitch;
• We determine the maximum bending moment - information on the channel is in the GOST tables. We calculate: Mmax (bending moment) in KiloNewtons per meter is equal to the product of the design load by the square of the length of the channel. Clarification: 1 kNm is equal to 102 kgcm.

The moment of resistance of the product - Wtr, is found by the following calculations: Mmax is multiplied by the coefficients for operating conditions and divided by the coefficient taking into account plastic deformations - 1.12. We compare the obtained result with the provisions in GOST and find the parameters of the desired profile.

Important!

According to the channel number, you always need to select a little more than what was calculated.

Types of loads and channels

View A.

"Canopy over the entrance." This type includes beams with rigid embeddings. The load is usually applied evenly. These could be canopies over entrances. Welding is used for their manufacture. They are made of two channels attached to the wall, and the space is filled with reinforced concrete.

View B.

“Interfloor slabs” Rigidly fixed single-span beams, the load on which is distributed evenly. Usually these are floor beams between floors.

Species C.

"Hinged balcony support." The beams have two supports with a cantilever, the load is distributed evenly between them, but they extend beyond the outer walls. This is necessary to create support for the balcony slabs.

View D.

"Under two jumpers." These are single-span hinged-supported beams on which two concentrated forces act. Usually these are lintels on which another pair of floor beams rests.

Species E.

"Under one jumper." These are single-span hinged-supported beams where one force is concentrated. Usually these are lintels on which one beam of another floor rests.

After it has been clarified what type of channel this channel belongs to and where the main load will go, a calculation formula is selected.

Preliminary Considerations

The calculator provides calculations of beams for various schemes of their fastening and load. The load of beams can be distributed (“q” in diagrams 3,4,5,9,15, etc.) or concentrated (“P” in diagrams 1,2,6,7,8, etc.)

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The fastening of beams can be: a) cantilever with rigid termination of one of the ends (for example, schemes 1,2,3 and others); b) “sealing - sealing”, when both ends of the beam are rigidly clamped (sealed), schemes 6,7,8,9; c) “hinge - hinge” (diagrams 12,13,14,15 and others), with the left hinge being fixed and the right hinge being movable; d) “sealing - hinge”, (diagrams 9,10,11 etc.)

Rigid embedding of the beam prevents the beam from turning and moving in any direction. A fixed hinge allows only rotation of the beam at the point of attachment in the vertical plane. The movable hinge allows the beam to rotate at the point of attachment in a vertical plane and move along its own axis.

An approximate method for calculating the load on a channel

To make the calculation you need to do the following:

-First, determine the total load that will act on the beam - and multiply it by the standard safety factor for loads.

-Multiply the result obtained by the pitch of the beams (in this case this applies to channels).

Next, you need to calculate the maximum bending moment.

All data for the channel is taken according to GOST.

The formula is as follows: the bending moment Mmax will be equal to the design load multiplied by the length of the channel squared. The unit of measurement is kiloNewtons per meter. (1 kNm = 102 kgcm)

Then proceed to calculate the required moment of resistance of the beam.

The formula is as follows: the moment of resistance Wtr will be equal to Mmax, which is multiplied by the operating conditions coefficients and divided by 1.12 (this is a coefficient for taking into account plastic deformations).

Thus we obtain the required section. But at the same time, you need to remember that the channel number must be greater than the required section moment.

Maximum permissible deflection: the most important characteristic of a channel

When choosing a structural material and approving it for use in construction, various calculation data are used: minimum moment of resistance, bending moment, normal stress, etc.

However, the most important characteristic is the maximum permissible deflection. It is calculated as follows: the coefficient 5/384 is multiplied by the fraction. The numerator of the fraction contains the product of the design load and ¼ of the length of the channel span. The denominator is the product of the moment of inertia and the longitudinal elasticity index of the material from which the channel is made (its modulus).

The results obtained are a comprehensive calculation that allows you to find out whether the channel is really suitable for use in a particular part of the structure.

Conventions in channel markings - how to understand them?

And since the main purpose of the channel is to withstand loads, from its markings it is first necessary to find out the parameters that will allow this load to be calculated, namely, the composition of the steel, its strength, rolling quality, and so on.

What can you learn from the labeling?

For example, before us is a package of hot-rolled channels, on which it is written: 30P-V GOST 8240-97/St3sp4-1 GOST 535-88

This means that we have a 30P channel - that is, with parallel edges and a section height of 30 cm. The letter B indicates the usual rolling accuracy B, made of steel St3, fourth category, first group.

The same channel, but only made of steel 09G2S with increased rolling precision will receive the designation 30P-B GOST 8240-97/345 GOST 19281-89

, in which 345 will mean the strength of steel corresponding to grade 09G2S.

But in the marking A 300x80x6 B GOST 8278-83/2-St3sp GOST 11474-76

the letter A will denote the high accuracy of profiling of a steel blank (strips) from the second category of steel St3sp, from which a bent equal-flange channel with dimensions of 300x80x6 is made (where 300 mm is the height of the section of the product, 80 mm is the width of the shelves, and 6 mm is the thickness of the shelves and walls)

What load can channel 10 withstand?

The channel is considered the most common rolled metal product. This is a metal blank in the form of a beam, which has the shape of the letter “P”. The main useful functions of the channel include increasing the stability and rigidity of various structures, which allows the latter to withstand high loads.

The product is manufactured by hot deformation of metal on a rolling mill without the subsequent use of additional heat treatment. All norms for the production of 10P channel are specified in the norms of the GOST 8240-97 standard.

Channel 10 technical specifications

Each GOST standard specifies the technical characteristics of a 10P channel depending on the type and method of its manufacture. But the main ones include the width and length of the workpiece.

The standard length of channel 10 varies from 4m to 12m, but there are also non-standard sizes with a length of 13m. In this case, metal rolling companies produce the product to order. After the length of the rolled product, its marking is indicated - the index “P”, which means the presence of parallel edges in the metal product. The width of the channel between the shelves indicates its number in the assortment.

When producing the product, ordinary steel grades PS 3 or SP 3 are used, low-alloy steel - 09g2s, which increases the strength and reliability of the workpiece, since the steel contains a manganese alloy. You can usually distinguish a hot-rolled billet from a cold-rolled one by its appearance: a hot-rolled channel has a slightly rounded outer corner. The weight of one meter of the product is 8.59 kg.

What load can a 10 channel channel withstand?

Thanks to its technical characteristics and design, the product is able to withstand axial loads and is very resistant to bending loads. The small thickness of the channel serves, as a rule, for the construction of floors on a small shoulder and the creation of crossover structures of medium length.

Channels are used to make supports for high-voltage power lines, cranes, oil rigs and other structures. Also, such samples often find application in machine tool building, mechanical engineering and carriage building.

The wide spread of 10P channel in industrial production has been facilitated by its high strength and reliability characteristics, as well as its affordable price.

Channels come in different sizes and therefore for each type of work it is necessary to select special rolled metal. And for this you need to know what load you can count on it. The channel load is calculated based on what type of beam it is and where the load goes. It is more convenient to make the calculation by presenting a diagram of the beam.

Choosing a channel from the point of view of economic feasibility

The cost of a channel is calculated based on data on weight and cost per ton:

* Price as of December 2022, see the current prices on the date of purchase in the online store in the Rolled Metal - Channel section.

It can be noted that from the conditions for calculating the strength of a channel working in bending, a more economical solution would be to use a bent channel in comparison with a hot-rolled one.

Moment of resistance of a channel when designing floors

When designing floors and load-bearing metal structures, one strength calculation of the load on the channel is not enough. To ensure the reliability of the designed structure, it is also necessary to calculate the rigidity of the channel. The deflection in this case should not exceed the permissible value. This profile check is mandatory when designing floors for residential and other premises. For example, let's take the same beam as before. The distributed load acting on it is 50 kgf/m or 500 N/m. The moment of inertia of the 10P channel has the value Ix = 175 cm4. When checking a beam for rigidity, its relative deflection is determined using the formula:

• f/L = M∙L/(10∙E∙Ix)≤[f/L], where

M – bending moment, N∙m L = 1000 cm – rod length E = 2.1∙105 MPa – modulus of elasticity of steel Ix = 175 cm4 – moment of inertia of the channel section

The moment of resistance of the channel, the bending moment is equal to: M = q∙L2/8 = 500∙102/8 = 6250 N∙m.

Then the relative deflection of the 10P channel will be: f/L = 6250∙1000/(10∙2.1∙105∙175) = 0.017 = 1/59

If we compare it with the permissible values ​​regarding deflection according to SNiPs, then this channel cannot be used for interfloor ceilings, since the permissible value there is 1/200. Therefore, despite ensuring the strength of this design, it is necessary to select a larger channel profile and check it for rigidity.

Hot rolled steel channel: standards, range, characteristics

The range of these products is determined by GOST 8240-89. The profile size is characterized by a number that is equal (approximately) to the height of the wall, taken in centimeters. In accordance with the standard, the following products are produced:

• With a slope of the inner edges of the shelves. The marking contains the letter “U” after the number. The standard provides for the production of products with a wall height of 50-400 mm, a shelf width of 32-115 mm, a wall thickness of 4.4-8.0 mm, and a shelf thickness of 7.0-13.5 mm. If the designation contains the letter “a” between the profile number and the letter “U,” this means that the product has an increased width and thickness of the shelves. The main area of ​​application of this type of channel is construction. Due to some thickening in the inner corners, the profile has increased strength characteristics. Such metal products are used in frame construction, for the installation of floors, the construction of trusses, stairs, small architectural forms, and metal structures for various purposes.
• With parallel inner edges of shelves. The marking indicates the letter “P” after the number. The index “a” indicates the presence of reinforced shelves. In accordance with the standard, the wall height of products is in the range of 50-400 mm, shelf width - 32-115 mm, wall thickness - 4.4-8.0 mm, shelf thickness - 7.0-13.5 mm. This type of channel has areas of use similar to products with sloped internal edges of shelves. A profile with parallel internal edges is effective in cases where the interface with other parts of the structure occurs along the internal surface of the product.

Table of geometric characteristics of hot-rolled channel

Calculation of the table weight of the channel is carried out using the average value of the density of various steel grades - 7.85 g/cm3.

How much can a channel weigh?

Bent steel channel: GOST, assortment, technical characteristics

The starting material for the production of bent profiles is hot- or cold-rolled steel strip. The manufacturing process takes place on profile bending units. A bent metal profile can be distinguished from a hot-rolled one by its rounded outer corners and the same thickness of the wall and shelves, which does not exceed 8 mm. Bending eliminates some surface defects. Unlike hot-rolled metal products, which are produced only as equal flanges, bent metal products are produced both as equal and unequal flanges. The range of equal flange products is determined by GOST 8278-83, unequal flange products - by GOST 8281-80. Their range is much wider than the list of hot-rolled U-shaped products. The height of the wall of the equal-flange profile is 25-410 mm, the width of the shelf is 26-65 mm, the wall thickness is 2-8 mm.

Due to the strength, which is inferior to the similar characteristics of hot-rolled metal products, various brands of bent channel are used as additional reinforcing elements in metal structures, during finishing work, and reconstruction of dilapidated buildings, in which the low mass of metal plays a decisive role.

Numbers, letters and GOSTs

According to the production method, the channel can be bent or hot-rolled. It is easy to distinguish them even for a non-specialist - a hot-rolled channel has a clearly defined edge, while a bent channel it will be somewhat rounded. Other features of various types of channel are determined by their markings.

In particular, the letters A, B and C in relation to batches of hot-rolled channels will indicate that the rolling was carried out with high (A), increased (B) or normal accuracy (C).

The channel number indicates the height of its section, expressed in centimeters.

The width of the profile corresponds to the width of the shelf and can range from 32 to 115 mm. The marking of a channel, for example 10P, reflects its height and type of profile. The height of the channel section is generally the main parameter in its marking. The channel number is its height in centimeters, and the letters adjacent to it indicate that the channel cross-section can be:

1) with a slope of edges (series U and C), where U is the slope, and C or Sb are special series. 2) with parallel edges (P, E and L series), where E means economical series, and L means light. Letters C (for example - 18С, 20С, etc.) can be found in products intended for the automotive industry or for the construction of railway cars (GOST 5267.1-90). Sometimes there are also exotic types of channels. For example, GOST 21026-75 determines the parameters of channels with a bent flange (they are used in the production of trolleys for mines and mines).