Punching openings in walls is a series of actions aimed at expanding or increasing the number of niches and passages in load-bearing partitions. In what order the work should be performed depends on the material for the structure. Particular care is taken when working with small bricks. During construction, the mechanical strength of the wall decreases, so the progress of punching and load distribution should be monitored.
Iron support device
Types of steel angle used for the manufacture of metal jumpers
Angle steel used in construction is made in two ways - rolling and bending. In structures designed to withstand heavy loads, a rolled angle is usually used, since it is characterized by:
- increased strength due to thickening on the inside of the corner;
- clear contours of the outer corner, while the metal product obtained by bending has a slightly rounded outer corner;
- large wall thickness: bent products are usually made thin-walled, since the bending process is carried out without heating, and very powerful, expensive equipment is required to work with thick products.
For the manufacture of rolled corner profiles for ordinary purposes, carbon steels of ordinary quality are used, St3 is most often used. For metal products planned for use under conditions of increased loads and/or in regions with cold climates, low-alloy steels are used, most often 09G2S.
Based on the width of the shelves, there are equal and unequal corners. Products with equal shelf widths are widely distributed.
Advantages of using steel angle
For the manufacture of lintels, reinforced concrete monolithic and prefabricated lintels are used - slabs, bars, beams, prefabricated products made of cellular concrete. However, for some building structures, only lintels made of rolled steel are suitable, including angle bars.
Advantages of using a corner:
- operational installation;
- the ability to lay bricks and blocks on metal lintels immediately after installing the rolled products;
- strength and reliability of metal products, subject to the correct choice of assortment, depending on the type of masonry and the planned load.
Wooden
A type of lintel is widely used in the construction of private brick houses. Such designs have many disadvantages, including:
- able to cope with high loads;
- low durability;
- are rotting.
The only advantage is the low cost of the product. The depth of support of the lintels should not be less than 15 cm at each edge. Recently, wooden partitions have been used only in frame houses.
The use of steel angles for lintels over openings in buildings made of aerated concrete or brickwork
Brickwork can withstand its own weight well after gaining grade strength with masonry cement-sand mortar in cases where the opening is of moderate width and does not bear the load from the ceiling. However, during the period of hardening of the mortar, the brickwork requires support, which can be provided using angle steel.
When using a corner to strengthen a brick wall above an opening, the following conditions must be met:
- the support on the masonry must be at least 200 mm on each side;
- if the walls are to be plastered, then the steel corners are wrapped with plaster mesh;
- rolled products are painted on the inside and outside before use;
- the gaps between the brickwork and the rolled products are filled with cement-sand mortar of a grade not lower than M100.
Features of using angle bars for installation over openings in walls made of aerated concrete:
- The corner is cut into the body of the block, retreating from its edge by about a third of the width. It is prohibited to place the rental on the inside or outside of the wall.
- Above the lintel, the blocks are laid on glue and the vertical seams are filled with an adhesive mixture. After the glue hardens, a structure is formed that is not inferior in strength to an aerated concrete block.
- After installing the windows, the corner from the outside is insulated and plastered.
Attention! If installation is incorrect and the external part is not insulated, condensation may form on the slopes inside the room.
For an opening up to 1.2 m wide, products with a shelf width of 50 mm are sufficient, 1.2-2.0 m - with a shelf width of 75 mm. When deciding which corner should be used for lintels of openings more than 2 m wide, calculations are made for strength and deflection.
Strengthening openings in frame buildings
For a frame building, the presence of lintels in the upper part of the openings is strictly necessary. The requirements described below are valid for frames made of both metal and wood.
If the width of the opening does not exceed two steps for installing the frame racks, the nearest side rack elements are connected by two horizontal crossbars, and then two vertical spacers are added between them, setting the required width of the opening.
If the opening width is equal to three or more distances between the frame posts, it is decorated with crossbars in the same way. For additional support of short racks above the opening, they are unloaded onto adjacent ones using diagonal braces running from the center outward. In all cases, the cross-section of the crossbars should not be less than the size of the rack elements of the frame.
If the opening exceeds the width of five times the distance between the posts, the verticals closest to it should be double. The internal pair is connected to each other by a horizontal jumper, and the external one is the same, but higher by half the height of the opening. The space between two horizontal crossbars is filled with a diagonal stiffening mesh based on the principle of floor trusses.
Lintels for window and door openings: types, sizes, installation features
It is difficult to imagine a house in which there are no windows or doors. In order to make them, structures are needed to cover the openings.
Reinforced concrete lintels are used for this purpose. Their main function is to transfer the load from the ceiling and brickwork to the side sections of the walls (piers).
The main materials for making jumpers are:
- Reinforced concrete - due to its affordable price and high manufacturability, is widely used in capital construction;
- Steel (I-beam or channel) is used to a limited extent to cover wide openings where windows and doors are subject to heavy loads.
The markings and overall dimensions of reinforced concrete structures are specified by GOST 948-84 . This building standard divides all industrially produced lintels for window and door openings into several basic types:
- PP - slab (width more than 25 cm).
- PB - block (width less than 25 cm).
- PG - L-shaped beams are equipped with a protrusion designed to support floor slabs.
- PF - façade (used for openings in which the masonry protrudes more than 25 cm from the wall surface).
Depending on the size of the working load, all prefabricated lintels are divided into load-bearing and non-load-bearing. The former perceive and transmit to the walls the weight of the ceiling and the upper part of the wall. The latter can only withstand the load from the wall and their own weight.
The load-bearing capacity of reinforced concrete lintels ranges from 100 to 3,700 kg/m. Concrete provides these structures with the necessary compressive strength, and steel reinforcement absorbs tensile forces.
Main varieties
To construct the lintel, especially durable materials are used; they can be from the same category as the wall itself, or they can be radically different from the original structure. The main condition is to ensure the strengthening of the opening, as well as the uniform distribution of the applied load. All this will help to adjust further calculations for the structure in the wall.
In order to strengthen the opening in the load-bearing wall of a panel house or any other house, the following materials can be used:
Depending on the chosen option, the installation of lintels above the opening differs in technological terms. Brick structures should also be placed in a separate category; they should be considered in more detail.
The main types of lintels for strengthening a doorway
Standard size range, weight and marking
The GOST dimensions of reinforced concrete lintels are as follows:
- length from 103 to 596 cm;
- height from 12 to 44 cm;
- width from 14 to 38 cm.
The weight of these structures directly depends on the dimensions and can range from 20 kilograms to 2 tons.
Reinforced concrete lintels are mounted on cement mortar. Cutting of these structures for the purpose of adjustment is not permitted. If the wall thickness is large, the opening is covered with several timber lintels, laying them parallel to one another.
Special markings help you understand the wide range of these products. It consists of three groups of alphanumeric symbols separated by a dash.
The first digit indicates the GOST number of the section. It is followed by two letters indicating the type of jumper and two numbers of its length (in decimeters). The second group of numbers contains information about the design load in kN/m. The third group of marking symbols is service and contains data on the degree of concrete density, the presence of mounting loops, the degree of seismic resistance or the class of reinforcement.
For example, let’s decipher the standard designation of a reinforced concrete jumper: 2PB22-3-p:
- 2 — section number (indicated in the GOST table);
- PB – bar lintel;
- 22 – length in decimeters (220 cm);
- 3 – bearing capacity (design load, 3 kN/m);
- p – the product has mounting loops.
To increase the load-bearing capacity of lintels, prestressed reinforcement is used. Such structures can be distinguished by the type of reinforcement indicated at the end of the marking. For example, 5PB21-27-AtV. In this case, AtV is a type of prestressed reinforcement.
GESNr 53-25-01
Installation of metal lintels in the walls of existing buildings
LOCAL RESOURCE STATEMENT GESNr 53-25-01
| Name | Unit |
| Installation of metal lintels in the walls of existing buildings | 1 t of metal structures of lintels |
| Scope of work | |
| 01. Punching nests, grooves, holes. 02. Preparation and installation of metal elements. 03. Sealing nests and furrows. | |
PRICE VALUES
The price does not contain overhead costs and estimated profits; accordingly, the direct costs of work for the period 2000
(prices of the Moscow region), which are calculated based on
2009
. For further calculations, this cost must be multiplied by the conversion index to current prices.
You can go to the pricing page, which is calculated based on the standards of the 2014 edition with additions 1 The basis for using the composition and consumption of materials, machines and labor costs are GESN-2001
LABOR COSTS
| № | Name | Unit Change | Labor costs |
| 1 | Labor costs of construction workers Grade 3.1 | person-hour | 165,88 |
| 2 | Labor costs for drivers (for reference, included in the price of the EV) | person-hour | 0,47 |
| Total labor costs for workers | person-hour | 165,88 | |
| Workers' compensation = 165.88 x 8.62 | Rub. | 1 429,89 | |
| Payroll for drivers = 7.05 (for calculating invoices and profits) | Rub. | 7,05 | |
We draw up a resource estimate for GESN with our own hands.
OPERATION OF MACHINES AND MECHANISMS
| № | Cipher | Name | Unit Change | Consumption | Article number Rub. | Total RUB. |
| 1 | 030401 | Electric winches with traction force up to 5.79 kN (0.59 t) | mach.-h | 0,16 | 1,7 | 0,27 |
| 2 | 040502 | Installations for manual arc welding (DC) | mach.-h | 0,74 | 8,1 | 5,99 |
| 3 | 050101 | Mobile compressors with internal combustion engine pressure up to 686 kPa (7 atm), capacity 2.2 m3/min | mach.-h | 0,47 | 90 | 42,30 |
| 4 | 330804 | Pneumatic jackhammers when operating from mobile compressor stations | mach.-h | 0,92 | 1,53 | 1,41 |
| 5 | 400001 | Flatbed vehicles, load capacity up to 5 tons | mach.-h | 0,2 | 87,17 | 17,43 |
| Total | Rub. | 67,41 | ||||
CONSUMPTION OF MATERIALS
| № | Cipher | Name | Unit Change | Consumption | Article number Rub. | Total RUB. |
| 1 | 101-1529 | Electrodes with a diameter of 6 mm E42 | T | 0,009 | 9424 | 84,82 |
| 2 | 201-9002 | Steel structures | T | 1,04 | 0,00 | |
| 3 | 402-9078 | Cement-lime mortar M50 | m3 | 0,54 | 0,00 | |
| 4 | 404-9001 | Brick | 1000 pcs. | 0,57 | 0,00 | |
| Total | Rub. | 84,82 | ||||
TOTAL BY RESOURCES: 152.22 RUB.
TOTAL PRICE: RUB 1,582.11.
Look at the cost of this standard at current prices open page
Compare the price value with the value of FERR 53-25-01
To draw up an estimate, the price requires indexation of the transition to current prices. The price is based on the GESN-2001 standards, as amended in 2009.
in
2000
.
To determine intermediate and final price values, the DefSmeta
Approximate prices and selection features
The most popular length of lintels used in residential construction is from 1.2 to 2.2 meters. The estimated cost of slab-type structures (width 38 cm) ranges from 600 to 4000 rubles. Bar lintels of similar length can be purchased at prices ranging from 250 to 1,700 rubles per piece, depending on the selected width and height.
When choosing the type of lintel above the windows, do not forget that slab lintels can only be installed in a non-load-bearing wall (on which the floor slabs do not rest). Bars can be installed in any type of enclosing structures (non-load-bearing and non-load-bearing).
The width of all manufactured reinforced concrete lintels is a multiple of the width of the masonry. Thanks to this, they are easy to choose for any object. For example, for partitions with a thickness of half a brick (12 cm) and one brick (25 cm), there are more than three dozen standard sizes of products ranging from 1 to 6 meters in length on the market. For thicker walls (1.5 bricks or more), the industry produces slab lintels.
For installation in non-load-bearing walls, it is more profitable to use slab lintels, because their width is equal to the width of the wall. In this case, you will have to use several pieces of timber beams.
When purchasing, you must take into account the support of the lintels on the wall - the main criterion for the reliability of the ceiling. If the area of the supporting part turns out to be less than the standard, then destruction of the material on which this structure rests may occur. To restore the load-bearing capacity of the pier, you will have to do the labor-intensive dismantling of the lintel, dismantling and re-laying the destroyed area.
In general, for a load-bearing brick or aerated concrete wall, the depth of embedding (support) of the lintel should be at least 25 cm. For a self-supporting wall, the size of its supporting part can be reduced to 12 cm. The lintel above the doorway should extend its ends onto the wall no less than 20 cm.
The height of the lintel is selected based on the calculated load on the opening. The developer does not need to perform complex strength calculations, since the full specification of these structures, indicating the dimensions, is contained in the design documentation. During independent construction, you should not engage in amateur activities with the selection of jumpers. It is better to contact the designers for advice.
The technology for installing lintels over openings is determined by the type of wall (load-bearing or non-load-bearing). In the first case, a powerful reinforced concrete beam is placed under the slab. Two other smaller sections are placed in the middle of the wall. The outer one goes down one row of bricks, forming a quarter.
In a non-load-bearing wall, the lintels are the same size. The outer one is lowered by a quarter, and the rest are placed at the same level.
Instructions for the calculator
Before you begin the calculation, carefully read the instructions to avoid mistakes.
Initial data
Type 1
Span length (L) is the distance between the edges of the supports above the opening that is covered by a metal lintel.
Width of masonry (B) - this value depends on which option is yours (see figure):
- Option 1 - the lintel takes the load from the entire thickness of the wall.
- Option 2 - the lintel takes the load from part of the wall, for example, only from the facing brick.
Masonry material - here you choose the material from which the wall is made. If it is not found or you are using a material with a different density (since materials such as foam concrete, expanded clay concrete, gas silicate are calculated with maximum densities, i.e. the heaviest), then you can select the density of materials from those proposed.
Abbreviations:
With. empty — silicate hollow.
With. full - silicate solid.
k. empty — ceramic hollow.
full — solid ceramic.
ceramic concrete - expanded clay concrete.
Masonry height (H) - you need to be especially careful here. So, there are 2 cases (see picture):
- Case 1 - when the distance between the openings in height is greater than half the span, i.e. H>L/2, or there are no more openings above the opening. In this case, column “H” remains empty or the number 0 is entered there.
- Case 2 - the distance between openings is less than half the span, H
Design resistance Ry - usually 210 MPa is used for calculations. But if you are sure that you will be supplied with a profile made of the steel of exactly the grade you need, then this value is set according to the scheme:
- steel grade C255 - Ry = 250 MPa.
- steel grade C345 - Ry = 340 MPa.
Load from floor slabs (q2) - load that is transferred from the overlying floor slabs to the lintel (through the masonry or directly onto it).
Type 2
Further we will talk only about new variables.
Floor beam load (Q) is the load that occurs at the floor beam support and is transferred to the lintel.
Type 3
Distances (A and C) - distances from the edge of the supports to the place of application of loads from the beams.
Result
Fmax is the maximum permissible deflection for lintels according to SNiP 2.01.07-85* (SP 20.13330.2011). "Loads and impacts."
Wreq and Jreb are the required moment of resistance and moment of inertia for the profile that will be used as a metal jumper. They are selected according to assortments so that the values of W and J of the profile are greater than Wrequired and Jrequired. Also, when selecting a profile, you should take into account its orientation in space.
An example of selecting a profile for a metal lintel.
An unequal corner according to GOST 8510-86 will be used as a jumper. The obtained values according to the calculation are Wreq = 0.61 cm3, Jreq = 1.90 cm4. And since we select the profile according to the deflection, we focus on Jreq. The nearest larger value in the X direction is for the corner L32x20x4 with Jx = 1.93 cm4, in the Y direction - L40x30x4 with Jy = 2.01 cm4.
svoydomtoday.ru
Supporting a metal lintel on a brick wall
Purpose of the lesson: to consolidate theoretical material, learn how to select lintels over window and door openings to brickwork.
Contents of the lesson: on A4 graph paper at a scale of 1:100, draw up a plan diagram for the list of lintels according to the given options, fill out the list of lintels in Form 1 and the specification of precast reinforced concrete elements (Appendix A).
Initial data: diagrams of floor plans (based on materials from practical work No. 1). Jumper types are given in Appendix B.
Procedure for conducting the lesson:
1) Before proceeding with the selection of lintels, it is necessary to complete the floor plan diagrams for the list of lintels. An example plan is shown in Figure 6.1.
To do this, we schematically draw the floor plan of the house with the designation of openings, observing the scale. An example of the circuit is given in Figure 6.2.
2) Assign each opening a position (mark), which is assigned in accordance with the width of the opening and the static function of the wall - load-bearing, self-supporting or non-load-bearing. An example is given in Figure 6.3.
3) Determine the size of the opening: (width and thickness).
4) Select cross-sections of lintels, combining them from several bars or a combination of bars and beams. In load-bearing walls, place “load-bearing” lintels in places where the slab (beam) is supported, and fill the remaining width of the walls with “non-load-bearing” lintels. An example is given in Figure 6.4.
Section diagrams are drawn in table form 2.1 GOST 21.501-93.
Figure 6.1 1st floor plan
Figure 6.2 Layout of the 1st floor
Figure 6.3. Marking of openings
Figure 6.4 Diagram for installing lintels over openings in external load-bearing brick walls
For ease of work, keep a count of the required length of jumpers next to the sheet. To do this, we add to the width of the opening the value of the minimum support of the lintels on the wall: “non-load-bearing” lintel + 240 mm (120 mm on each side), “load-bearing” lintel + 500 mm (250 mm on each side). The brands of jumpers are indicated by positions on the section diagram. The “non-load-bearing” lintel takes only the weight of the masonry, and the “load-bearing” lintel takes the weight of the masonry and the floor resting on it.
5) Select “load-bearing” and “non-load-bearing” jumpers according to Appendix B.
6) In load-bearing, self-supporting walls and partitions, use only “non-load-bearing” lintels.
7) If a quarter is required, lower the external reinforced concrete lintel by a quarter amount equal to 65 mm.
The selected brands of lintels are indicated in the specification of prefabricated lintel elements (Appendix A)
An example of selecting lintels in a building with brick walls
Guidelines: An example of selecting lintels in a building with brick walls. The thickness of the external walls is 510 mm, the internal walls are 380 mm.
Stage I. According to the plan, Figure 6.5, determine load-bearing and non-load-bearing walls
Along the axis, 1-window opening is 910 mm (load-bearing wall 510 mm thick).
Along axis 2 - doorway - 910 mm (load-bearing wall 380 mm thick).
Along axis A - doorway - 1010 mm (curtain wall 510 mm thick).
Along axis B there are 2 window openings – 1510 mm (curtain wall 510 mm thick).
There are two window openings of the same size on the building plan, so they will have the same lintel markings.
All openings have different widths, which means that the marking diagram should have four types of lintels: PR-1; PR-2; PR-3 and PR-4.
Figure 6.5 1st floor plan
Stage II . Draw a diagram of the 1st floor plan (Figure 6.6), indicating the positions of the openings. In the task it will look like this:
Figure 6.6 Scheme of the 1st floor plan with markings of openings
Stage III. Select “load-bearing” and “non-load-bearing” jumpers and sketch their diagrams:
1) To block an opening in a wall 510 mm thick, you will need four 120 mm wide timber lintels: 120 mm x 4 = 480 mm,
plus three 10 mm seams (10 mm x 3 = 30 mm). Thus, we get: 480 mm + 30 mm = 510 mm - a size equal to the thickness of the wall.
We have determined that the wall is load-bearing, so the outermost lintel on which the wall rests must be “load-bearing”.
We get: three jumpers – “non-load-bearing” and one – “load-bearing” (Figure 6.7)
Figure 6.7 Diagram of jumpers in a load-bearing wall 510 mm thick
2) To determine the length of the lintel to the width of the opening, add the value of the minimum support of the lintel on the wall (Figure 6.8 and Figure 6.9)
“non-load-bearing” lintels: 910 mm + 240 mm (120 mm on each side) = 1150 mm.
Figure 6.8 Scheme of supporting a non-load-bearing lintel over the opening
Using the table in Appendix B, we select the required size of the jumper, the size of which will correspond to the calculated length (in our example, 1150 mm). This turned out to be a jumper with the name 2PB13-1, the length of which is 1290 mm, height – 140 mm;
“load-bearing” lintel: 910 mm + 500 mm (250 mm on each side) = 1460 Figure 6.9 Scheme of supporting the load-bearing lintel over the opening
We find the required lintel in the table and do not forget about the design load (Appendix B), since the floor slab rests on the “load-bearing” lintel. We get a 3PB16-37 jumper, the length of which is 1550 mm, the height is 220 mm;
Jumpers PR-2, PR-3, PR-4 are selected using the above method.
When selecting a PR-4 lintel, it is necessary to take into account the wall thickness - 380mm.
In this case, 3 lintels with a width of 120 mm are laid above the opening:
120x3 = 360 mm; 360 mm + 20 mm (two seams of 10 mm each) = 380 mm.
3)We fill out the list of lintels according to form 6.1 - Figure 6.10, putting down positions in the section diagram, then fill out the table of specifications for prefabricated lintel elements (Appendix A). Examples of filling are given in tables 6.1 and 6.2.
Form 6.1 GOST 21.501-93
Figure 6.10 Jumper List
Table 6.1 Example of filling out the list of jumpers
Table 6.2 Example of filling out the specification of jumper elements
Amplification technology
When working with critical load-bearing structures, a mandatory condition for admission is the presence of additional supports supporting a temporary beam that absorbs and redistributes weight loads. They can be made in the form of columns made of bricks or by installing reliable jacks, steel beams or wooden beams at a short distance from the wall being broken through in the area of the future opening. After this, in the right places, using a hammer drill, through holes are drilled for metal pins supporting a temporary horizontal support.
This method allows you to remove a number of blocks and place a thick wooden beam, reinforced concrete lintel or metal channel in the resulting niche. The depth of the horizontal support depends on its height, the standard range varies between 15-30 cm. The lintels are secured with studs and concrete; dismantling of the lower rows begins after the solution has hardened. Strengthening is a prerequisite; the type, dimensions and thickness of the metal profiles to be laid in the case of load-bearing structures are justified by calculations, which can only be carried out by specialists.
The second, simpler method is to fasten two thick (at least 8 mm) corners, fixed with reliable metal bolts passing through the masonry. To press them in using diamond saws, two small slots should be made - to the depth of the supports along the length and taking into account the size of the shelf. To eliminate the risk of solution spillage, the cracks formed during drilling are covered with a cement composition. This technology makes it possible to obtain a fairly reliable lintel; this method is often chosen when moving openings in one’s home.
Support for the upper rows is required; a wall without a lintel quickly collapses and reduces the overall strength of the building. The exception is arches, but they are allowed only in non-load-bearing partitions. If there is any doubt about reliability, additional measures are taken. These include filling possible cracks and defects with cement-polymer mortar, installing a U-shaped frame or corners around the perimeter, or installing 2-3 horizontal shelves. The latter are laid by drilling longitudinal strips with diamond saws and placing corners in the slots. All metal elements are connected by welding or bolts, the joints are cleaned of scale, and the surface is treated with anti-corrosion compounds.
Sequence of punching an opening
The standard course of action after obtaining permission to make changes includes the following steps:
- Protecting the floor and nearby structures from broken bricks, eliminating the risk of damage to communications. At this stage, all unnecessary objects and baseboards are removed, furniture is moved away from the future passage to a distance of 2.5 m, and all surfaces are protected from dust.
- Marking and cutting to secure the lintel.
- Installation of supports to unload load-bearing walls.
- Laying the lintel with subsequent reinforcement with concrete. It is permissible to proceed to the next stage only after it has hardened.
- Punching with a hammer drill or diamond cutting from top to bottom, followed by removing bricks and removing excess debris.
- Check the condition of the edges and strengthen them if necessary.
- Agreeing on the correctness of the reinforcement, obtaining a completion certificate.
- Making changes to the registration certificate of the house in the BTI.
- Finishing.
Depending on the type of tool used, the formation of the walls of a new opening or its expansion is carried out using the diamond cutting method or by punching using a hammer drill, sledgehammer, wedges and collapsible tongs. The advantage of the first option: when using water-cooled saws, virtually no dust is generated, the masonry is not subject to shock and vibration, and the work itself takes a minimum of time. This method is recommended to be chosen when making changes to the load-bearing structures of the MDK, including due to low noise generation.
The disadvantages of diamond cutting include high prices and the need for expensive equipment; not all construction companies provide such services. Punching of openings is carried out with impact tools (compared to diamond saws, a hammer drill is more affordable).
The sequence of actions generally remains the same: several holes are drilled under the lintel, weakening the adhesion of the brick → the products are knocked out with a sledgehammer or hammer → all excess protrusions are knocked off, cracks and gaps are filled with cement-sand or polymer mortar → if necessary, the side edges are strengthened → all metal parts are cleaned and painted with anti-corrosion primers.
The holes are created carefully, the hammer drill is directed perpendicular to the wall. When working with ordinary internal partitions, you can start punching without reinforcement; the best option is to completely dismantle this section and standard support at the required height. Load-bearing structures clearly require the installation of additional supports; any actions aimed at destroying the masonry are carried out after transferring the load to the beams and the future lintel.
The expansion is carried out according to the same scheme, the only difference is the need to dismantle the old door frame. Given the small volume of bricks to be removed, it is recommended to do drilling using diamond saws. Supporting corners most often need to be lengthened; to avoid risks, it is worth replacing them. With rare exceptions, there is no need to place a new lintel for the opening. If the passage width exceeds 0.9 m, it is better to reinforce the new edges with a metal corner.
stroitel-lab.ru
20-10-2014: Rustam
Good afternoon. We really need qualified advice (a verdict, so to speak). We built a house, essentially didn’t do any calculations, everything was based only on advice from those who had already built something. The essence of the issue is that there is a bay window on the ground floor; it was not possible to cover the entire length with slabs in length, because... taking into account the bay window, the slabs needed 7.5 m (lay them even longer across). Therefore, above the bay window (at the place where it begins) they placed an I-beam 28, 6 m long, 4 m span, so the beam overlap was 1 m on each side. The bay window itself was covered with a slab, which with its side edge enters the beam (subsequently, the gap between the lower part of the slab and the beam was filled with a solution about 1.5 cm thick). On the other side of the beam, three floor slabs of 1.2 m x 6 m3 enter into it, i.e. e. If you look at the ceiling, you can see that on one side the beam includes three 6-meter floor slabs; on the other side, a 4-meter slab enters along the beam, which at its ends rests on the walls of the bay window. In addition, on the second floor, a wall 0.4 m thick rests on this beam and the slab that covers the bay window. from concrete blocks (weighing 20 kg each, size 40*20*20). The second floor is an attic, in the future it is planned to insulate the interior with some kind of lightweight material (cotton wool). Just above the bay window on the second floor there is a window (1.4 width * 1.6 height), the internal total length of the wall is 10 m. (if you look at the 1st floor from the corner then: 1m wall, 4m bay window span and 5m wall to the other corner), thus, the middle of the wall is the end of the bay window (if you look at the inside). Franton honeycomb 5m. At present, there are no visible deflections of the beam, but given that it will be necessary in the future to insulate the wall, make floors (wooden on joists) and other household loads, doubts have arisen about the strength of the applicable 28th beam. In this connection, I am considering the option - on the ground floor, at the corners where the bay window begins, put two posts (possibly the same from the beam) with which to support another beam (for example, the 20th), which will support the existing beam (the new beam will now stick out below, plus pillars at the edges). I tried to carry out the calculation myself using your method, and got the result: Mmax is equal to 5660 kgm, Wreq is equal to 270 cm3, which seems to give a reason to calm down, because in the table I saw for the 27th beam Wz equal to 371 cm3 (as I understand it, the same indicator), but I doubt the correctness of my calculations. I understand that this takes up your time, but, unfortunately, I have no other options to double-check, please tell me whether I should strengthen the existing beam and, if so, whether the method I described will help, Thanks in advance.
doctorlom.com
Supporting a metal lintel on a brick wall
During construction, prefabricated reinforced concrete products are used, which are produced in specialized factories and installed directly on site. Prefabricated reinforced concrete lintels are used to cover window and door openings.
By design, lintels are divided into load-bearing and non-load-bearing.
Bearing lintels - in addition to the mass of the masonry above it, carry the load from the floors resting on these sections of the masonry.
Non-load-bearing lintels - bear the load only from their own weight and the sections of masonry located above them.
Standard types and sizes of cross-sections of lintels manufactured using reinforced concrete products.
PB - timber lintels, up to 250 mm wide inclusive.
PP - slab lintels, more than 250 mm wide.
PG - L-shaped beam lintels, with a quarter for supporting or joining floor slabs.
PF - façade lintels facing the façade of a building and designed to cover openings with quarters with a thickness of the protruding part of the masonry in the opening of 250 mm or more, and a width of more than 250 mm.
to mark reinforced concrete lintels .
For example, the brand of jumper 5PB27-37 stands for:
5 - serial number of the cross section - 250x220;
PB - type of reinforced concrete lintel - bar;
27 - length of the lintel in dm with rounding - 2720 mm;
37 - calculated load of the lintel taking into account its own weight - 37.3 kN/m, rounded.
When making reinforced concrete lintels, heavy concrete mix M250 and reinforcement embedded products of 0.4-0.6 cm are used.
Covering openings with reinforced concrete lintels
The lintels are laid upon completion of the masonry at the level of the design marks. Before installation, check the supports at the installation sites with a level and spread the solution. Ordinary (non-load-bearing) lintels with a span of up to 2 m can be laid by masons by hand, while heavy load-bearing lintels are slung using mounting loops and installed with a crane. The correct installation is checked with a level or level.
During installation, it is necessary to lay the lintels only in a certain position, since the load-bearing capacity may vary depending on the number and location of the reinforcement.
Depth of support for reinforced concrete lintels
- in load-bearing walls - at least 250 mm (reinforced lintels on the supporting side of the floor) - in self-supporting walls - at least 120 mm.
To increase strength, if necessary, the masonry seams under the lintel supports are reinforced with mesh.
To cover the entire width of the masonry opening, the lintels are assembled from several elements, while the side surfaces of the lintels should not protrude from the plane of the wall.
Transportation and storage of reinforced concrete lintels
During transportation, the jumpers are laid in the working position; the longitudinal axis of the jumpers must coincide with the direction of movement of the vehicle. Between the rows of lintels it is necessary to use pads with a thickness of at least 25 mm and stacks of lintels not exceeding two meters in height.
You will only need four parameters that you know well:
– width of the opening to be closed;
– type of wall brick (silicate or ceramic);
– whether the wall is load-bearing (whether the floor slabs rest on it).
Four simple steps:
- Step 1: width of the opening to be covered. Enter the width of the opening in meters. The program is designed for openings with a width from 0.8 to 2.7 m; if you enter a larger width, lintels of 2.7 m will be calculated. The calculator does not care which opening is being considered: a window or a door.
- silicate one-and-a-half brick GOST 379-95 “Silicate bricks and stones” with a height of 88 mm.
Step 2: type of brick masonry walls. The program selects lintels for buildings from the following materials: ceramic single brick GOST 530-2012 “Ceramic brick and stone” with a height of 65 mm;
- All! By entering these four values, you will get a layout of lintels over one opening. In addition, the calculator will provide a specification indicating the brands and GOST standards of jumpers, the required number of jumpers per opening and the weight of each of them. Follow the same procedure for all openings of your house or cottage, and you will receive materials for a comprehensive order of all precast concrete lintels for the site. Thus, you will receive all the necessary information for purchasing jumpers free of charge. More details
After entering the data, you will see a diagram of the layout of the jumpers along the opening. If necessary, you can go back any number of steps and change any of the parameters. The layout scheme will be recalculated immediately.
The program lays out only timber lintels of PB grades in accordance with GOST 948-84 “Reinforced concrete lintels for buildings with brick walls.” This standard applies to reinforced concrete lintels made from heavy concrete and intended to cover openings in brick walls of buildings for various purposes.
The jumper brand consists of alphanumeric groups. For example, the brand of jumper 5PB27-37 is deciphered as follows: 5 – jumper with a cross section of 250×220 mm; PB – bar lintel; 27 – length of the jumper in decimeters, rounded to the nearest whole number (in this case 2720 mm); 37 – design load taking into account its own weight, rounded to the nearest whole number (in this case 37.3 kN/m). In brands of jumpers that have sling loops, a lowercase letter “p” has been added. For example, 5PB27-37-p.
If necessary, we are ready to provide documentation with initial data and specifications of selected jumpers completely free of charge. Specify the email address to which we will send the required document, which also contains information about the organization that carried out the selection of jumpers, the name of the responsible specialist and a link to the approvals of our organization that allow us to carry out the specified type of design work. An example of document formatting is provided at the link. s Laying out reinforced concrete lintels is one of the stages of designing a cottage. Other important steps include designing foundations, laying out floor slabs, designing basement walls and staircases. From us you can order a project for the load-bearing structures of a cottage or house, which will be completed by experienced designers (see “our team”). In our work we use modern software systems for calculations and design of load-bearing structures.
Supporting lintels on a brick wall taking into account SNiP
Supporting lintels on a brick wall SNiP is an important component of creating door and window openings during the construction of any object. A lintel is a construction element that is used in the area of a window or door. This is an irreplaceable part that keeps the balls of bricks from moving and the wall from collapsing.
Errors in the installation of jumpers can lead to the destruction of the entire building.
Consequences of errors
To avoid problems in the form of consequences during the construction process, it is better to entrust the selection of lintels to a professional construction engineer.
Based on an examination of the load-bearing capacity of the wall, the depth of support, and a number of mandatory characteristics, he will carry out the necessary calculations and determine exactly what material, shape and size the lintel will be suitable for in this particular case (length, width, thickness).
The consequences of errors are destruction, cracks, and displacement of bricks. To prevent them from arising, you must observe the following nuances:
Types of structures
It is difficult to find a room without windows and doors. But both windows and doors, despite their importance, usefulness, and functionality, are problem areas for workers. Their installation requires specially prepared openings. If we are talking about an ordinary wall, then the bricks are installed in rows, the load is uniform. In the wall where windows or doors are planned, the installation of lintels is required that will protect the wall from collapse. At the same time, the load on the lintel is high - 1 cubic meter of brick together with mortar weighs on average about 2 tons.
Lintels in brick walls come in several varieties:
Installation of steel lintels in load-bearing walls and partitions.
- Metal lintels are lightweight structures used for light loads. This could be fittings, a corner, a channel.
- Brick lintels. With their help, brick laying can be carried out horizontally and vertically.
- Arched masonry. Such a device is both a lintel and a component of façade decor. Its installation requires special tools and operating skills.
- Prefabricated reinforced concrete device. Such elements are installed when there is a large load on the openings. Often this is the construction of a 2nd floor, the use of complex structures in the project.
Reinforced concrete lintels can be of different types:
Lintels in brick walls are also divided into load-bearing and non-load-bearing structures. Load-bearing elements are high-strength products that can withstand considerable loads. Most often they are installed during the construction of 2 floors, on load-bearing brick walls. Non-load-bearing elements - capable of supporting several more rows of bricks in addition to themselves.
General requirements for reinforced concrete lintels:
- Mandatory presence of a welded reinforcement frame and a mixture of concrete.
- The construction of such structures is carried out only on horizontal, prepared sites.
- According to SNiP standards, the partition on a solid wall should extend 25 cm; and the minimum value in a brick partition between windows is 20 cm.
- It is important to install multi-element lintels in one position until the required span width is obtained.
Reinforced concrete
To strengthen the opening in the load-bearing wall of a house, reinforced concrete lintels are most often used. A preliminary calculation allows us to determine which element will be most suitable in this case. Such reinforcement of the opening can be made directly on site using formwork, reinforcement and liquid concrete.
To speed up the process, already cast elements are most often used. In order to secure them in the load-bearing wall, it is additionally recommended to use reinforcement to strengthen the sides of the opening. In other words, the metal is laid on those areas that are in direct contact with the reinforced concrete part.
The main requirement in this case is compliance with the installation rules. The lintel must completely cover the opening and extend approximately 25 cm into the wall. The exact requirements are determined by the specific type of structure. For each type of lintel and its relationship with the width of the opening, special standards have been developed.
Mostly straight products with metal filling are used. However, in some cases, it is possible to make a lintel according to a given template, which will follow the shape of the opening and at the same time act as reinforcement for the supporting structure.
Scheme of reinforced concrete lintel
Building up the structure
It is allowed to support the lintels on a brick wall SNiP by building up the structure on site. For this it is important to use formwork, i.e. box It must be selected in such a way that the lower part of the formwork or the bottom completely follows the dimensions of the opening. The formwork is nailed to the side parts, which should extend at least 20-25 cm into the structure. The side of such a structure is limited by brickwork. To ensure an accurate fit of the board to the wall, experienced builders recommend mounting the bricks in such a way that they protrude half the brick on both sides.
The box has small protrusions for installation, the board is attached and lies perfectly flat. Several rows of bricks are placed at the bottom of the structure (to hold the bottom of the box). This technology ensures strong and reliable fixation of the formwork. Then the elements are placed in the box and filled with solution.
For strong, reliable coupling of reinforcement elements, they can be placed in a joint ball of mortar from the side of the side stop or between the bricks. At the final stage, the side protruding bricks can be cut off using a grinder or safely used to tie up window decor parts.
The construction of one-story, small houses does not require massive reinforced concrete structures. Therefore, elements are selected for them from ready-made metal objects. More often they use a channel, ordinary reinforcement bars, a metal corner or strips. These supports are very lightweight, easy to use and quick to install.
Before installing such structures, it is important to correctly calculate the jumpers. There is a risk of the structure sagging, which could jam or destroy the window.
According to SNiP standards, such metal supports can bend no more than 1/200 of the length of the support itself.
To correctly calculate such installations, you will need the help of a specialist. If the calculation of the jumper is carried out independently, it is recommended that you familiarize yourself with the SNiP methods.
Process
The arrangement of lintels, with the formation of a unit and taking into account support in the wall, must take place according to the rules described in SNiPs. Since reinforced concrete lintels are used most often in modern buildings, the process of their installation consists of the following nuances:
Metal jumpers are lightweight. Presented in the form of channels and various forms of rolled steel, their advantage is that during operation they can be cut to the required length.
Brick lintels are mounted to the main wall along the top of the opening , and then connected to each other using a shelf from which clamps hang, placed in vertical seams. The clamps reliably reinforce the lintel, and it turns out strong.
Experienced craftsmen choose longitudinal, wedge, beam or vaulted installation methods. Concrete mortar for laying is mixed in small portions so that it does not harden quickly.
Recently, in most cases, builders have placed the professional BAUT reinforcement system into brick lintels.
A simple and reliable way to install a brick lintel - in the video:
