The construction of monolithic belts is widespread in construction practice. This is a mandatory element of rigidity during the construction of buildings of any purpose, configuration and number of storeys.
The main purpose of the belts is to create, as experts say, hard drives.
They seem to encircle prefabricated structural elements, giving them additional strength and rigidity when exposed to loads on the structural elements.
They are a continuous monolithic reinforced concrete belt, which is arranged:
- On strip foundations (pillows and blocks of basement walls);
- Armored belt on the walls;
- Reinforced belt for floor slabs and coverings;
- Under the mauerlats of hipped roofs.
When to install monolithic belts
The installation of an armored belt is provided in the following cases:
- In the presence of weak (subsidence) soils at the base of buildings and structures.
- With increased loads on the base and foundations (for example, in cases of construction of buildings with increased number of storeys).
- During construction in seismic areas.
- In some other cases. For example, if you have to support prefabricated reinforced concrete slabs box type wall material and weld them to the embedded elements.
In these cases, embedded parts are installed in reinforced concrete belts placed on top of the walls. The belt itself redistributes the load from the floor slabs onto the walls more evenly.
There are two types of belts:
- Horizontal
- Vertical
The installation of monolithic vertical type belts is carried out mainly in areas with increased seismic activity along with horizontal ones. The most widespread are horizontal belts.
Belt technology
All technological process consists of three stages:
- Formwork installation.
- Installation of reinforcement cages.
- Pouring concrete into the formwork of the structure.
Let's get acquainted with each point in more detail.
Formwork for monolithic belts
The design of the formwork must ensure its geometric immutability and rigidity throughout the entire process of use. It must be installed in accordance with the work plan.
Installation of formwork When installing belts along the entire thickness of the walls, first install and secure the formwork from the outside, as well as inside. It can be made from wooden boards, metal inventory elements (reusable), moisture resistant plywood, other materials.
There are examples, if this is provided for by the project, when its role is played by thin walls made of brick or aerated concrete. The space between them is reinforced and filled concrete mixture, and the walls themselves remain in the body of the structure.
The formwork is secured with nails using welding. Other fastening methods have not found widespread use. Since fasteners have to be constantly cleaned of any concrete mixture that gets on them.
Under the pressure of the concrete mass, in case of improper fastening, the panels can bend or move. This is fraught with the formation of uneven surfaces of the structure, which, after disassembling the panels, have to be cut down, hewn, and sometimes plastered.
Reinforcement of monolithic belts
Let's consider what kind of reinforcement is used for the armored belt. Reinforcement should be carried out with welded frames and meshes manufactured in factories. The use and installation of products in construction conditions is permissible for additional elements or sections of connection between frames and meshes.
The construction of monolithic belts involves placing reinforcement cages inside the formwork. They are spatial blanks of 4 or 6 bars of longitudinal reinforcement of a periodic profile (class A - III).
The diameter is most often 12-14mm (calculated and specified by the project), united by closed clamps made of smooth reinforcement with a diameter of 4-6mm with a pitch of 200-300mm.
In some versions, the diameter of the longitudinal rods can be large (specified by the project). For example, if a monolithic belt along the walls is made above the opening and is at the same time a lintel above a window or door.
Reinforcing bars are joined along their length by electric welding or knitting. When used, the most common fittings are class A – III. The overlap of the rods at the joints of the longitudinal reinforcement when joining them by electric welding must be at least ten diameters of the rods being joined.
Installation of fittings When connecting rods with knitting wire, the length of the overlap should be at least fifty times the diameter of the joined rods.
Joints should not be placed at corners of turns; the minimum distance from the joint to the corner of rotation must be maintained at least one meter.
When making spatial frames and assigning their dimensions, it is necessary to adhere to the rule of the so-called protective concrete layer.
This means that the distance from the inner edge of the shield to the nearest frame rod should not be less than 25 mm. This is necessary so that the concrete mixture completely covers the reinforcement when laying. The installation of monolithic belts is a responsible job that requires compliance with all tolerances during the execution of work.
The same gaps are provided at the bottom and top of the longitudinal rods of the frames. Before laying on the reinforcement, it is necessary to secure gaskets (crackers from cement mortar). They provide a standard gap between the formwork and the reinforcement to form a protective layer.
To control electric welding work at a construction site, a welding work log is kept. Acceptance of the laid reinforcement into the structure is formalized. When the reinforcement is completed and accepted according to the act, you can begin concreting.
Concreting of monolithic belts
Styling concrete composition It is advisable to perform the entire volume at once. If this cannot be done, then the number of breaks should be minimal.
In this case, in places where concreting is interrupted, it is necessary to construct a seam, which is a strictly vertical cut of concrete. Concreting joints must not be made above openings and at a distance of less than 300 mm from the edge of the opening.
Dimensions cross section belts are assigned by the project. The thickness of the monolithic belt is usually equal to the width (thickness) of the wall. The height is taken by calculation and ranges from 150mm or more.
The grade of concrete is specified by the project, but, as a rule, it is not lower than grade M-200. The top of the belt should be at the same mark in all places. For this purpose, special marks are applied to the formwork using a level or level.
The construction of monolithic belts in some cases involves the installation of embedded elements when this is provided for in the project.
For example, arranging a monolithic belt under the Mauerlat. Mauerlat hip roof must be firmly connected to the walls so that powerful winds do not throw the roof off the building.
Work completed Concrete must be vibrated (compacted) during the laying process; the upper edge of the concrete is aligned with the marks under the mark. The duration of vibration should ensure good compaction of the concrete mass.
The main indicators of this:
- Stopping its precipitation;
- The appearance of cement laitance on the surface;
- The end of air bubbles.
Where the density of the reinforcement does not allow normal compaction of the concrete mass with vibrators, compaction is carried out by bayoneting. When concreting, it is necessary to fill out a log concrete works. It is checked, like the reinforcement log, by a representative of the customer.
Placed concrete should be properly monitored and maintained. Suitable temperature and humidity conditions come down to a number of measures. This means watering it with water, covering it with sawdust, shields, sand, which should be kept moist.
Removal of formwork is carried out after the concrete mixture reaches strength, guaranteeing the safety of surfaces, corner edges. It is usually removed after 2-3 days depending on weather conditions(air temperature, humidity).
When accepting completed work, you should check the structure’s compliance with the working drawings, the correct location in plan and height.
Reinforcement products must have certificates of conformity. Concrete laid into the case - the results of laboratory tests of the cubes for strength, passports.
The construction of monolithic belts is necessary to give the structure rigidity and strength. As well as the uniform redistribution of loads on the underlying structures of the building. I suggest short video on this topic.
In order for the house to be built on our own, was durable and served without problems long years, it is necessary to ensure the rigidity of the structure and high-quality connection of the walls. To do this, it is necessary to erect an armored belt under the floor slabs.
To construct a high-quality reinforced belt, it is important that the circular pouring process be continuous and one-time.
This important detail load-bearing structure is a solid strip of concrete reinforced with metal, which is laid along the perimeter of the house under the ceiling.
Monolithic reinforced belt distributes pressure evenly along the entire perimeter of the wall and provides a flat surface for subsequent overlapping.
Monolithic belt erected along the perimeter of the walls of each floor under construction, on top floor it plays the role of a base for the roof and. In this case, window and door lintels can be made minimum size with a small amount of reinforcement, since the belt takes on the main load and distributes it evenly.
How necessary is an armored belt?
Most often, a monolithic belt is a construction necessity, but in some cases such structural strengthening is not required.
You can do without an armored belt if:
- the foundation is poured below the soil freezing level;
- The walls of the house themselves are made of brick.
But even if these conditions are met, it is necessary that the floor slab extends onto both sides of the wall by at least 12 cm, and that the building itself is located in a seismically safe area.
An armored belt is necessary if:
If the walls are made of gas silicate blocks, then an armored belt is necessary, regardless of the purpose of the room on the second floor.
- The house is multi-storey. In this case, the presence of monolithic belts is prescribed by regulations;
- The walls are built from porous materials, such as cinder blocks or aerated concrete. Under uneven pressure from the floor slab, these materials begin to crumple and quickly collapse;
- The building is being built on soft soil. In this case, there is a danger of subsidence of the house and, as a result, the formation of cracks in the walls. The monolithic belt will act as a screed and prevent cracks from occurring. Inspect old buildings in neighboring areas. If they are covered with cracks running down from the roof and up from the ground and the corners of the windows, then the construction of a reinforced belt is clearly necessary;
- The foundation of the building is made of prefabricated blocks or shallowly buried. The reinforced belt will evenly distribute the pressure of the slabs along the entire perimeter of the foundation;
- The house is located in a seismically active zone.
Return to contents
How to build a reinforced belt?
A monolithic belt is a structurally simple element. Formwork is built along the perimeter of the wall, into which it is mounted metal fittings. Then the structure is poured with concrete and insulated.
To construct a monolithic armored belt, the following materials are required:
For 2 storey building The armored belt is made after the construction of the walls of the first floor, before laying the floor slabs, and after the construction of the second floor, before installing the roof.
- Plywood/boards;
- Quick installation;
- Self-tapping screws;
- Nails;
- Ribbed metal rods;
- Bricks/stones;
- Concrete/sand, cement, crushed stone;
- Cellophane film;
- Insulation (foam);
- Knitting wire.
And tools:
- Welding machine;
- Screwdriver;
- Hammer;
- Concrete mixer;
- Building level;
- Hammer.
Return to contents
First stage: erection of formwork
Most often, the formwork is assembled on the basis that the armored belt will be approximately 15-30 cm in height, and the width will either be narrower than the wall or the same size as it. In the second case, the formwork moves deeper into the wall, which makes it possible to subsequently fill the resulting gap with insulation.
The optimal materials for formwork are plywood, OSB boards, and boards. The formwork must be mounted so that its upper part is in a perfectly horizontal plane. This can be achieved by adjusting the installation using a building level.
There are several ways to install formwork:
If you step back 2-3 cm inward when installing the formwork, and fill the “niche” after filling thermal insulation material, heat loss through the armored belt will decrease.
- Fastening using electric welding. In this case, the anchors are passed through the formwork walls, and the plugs are welded;
- Fastening with quick installation. This method is much faster and easier to perform, but it requires some preliminary preparation. Installation practically does not adhere to materials such as aerated concrete or cinder block. If the main part of the building is built from similar materials, then last rows under the proposed belt it is necessary to lay out brick.
Holes are drilled through the board attached to the wall at a distance of 700 mm from each other. The fungus is inserted into the holes and secured with a screw. For quick installation, it is better to take 6x100 mm and a 6 mm drill. When removing the drill from the resulting hole, you need to swing it a little in different directions. The hole will increase slightly and the wood fibers will not interfere with the installation of the fungus.
We fix self-tapping screws at a distance of 1 m on the upper edge of the board, and nails are driven into the facing brickwork in the same way. Self-tapping screws are tightened in pairs with nails using tying wire.
Return to contents
Second stage: production of fittings
The frame is prepared on the wall in a gutter made of removable formwork, since in finished form he is very heavy.
For the manufacture of the reinforcement frame, it is necessary to use only ribbed rods. Concrete mortar is attached to the uneven surface of the ribs and thereby provides greater load-bearing capacity and tensile strength.
The rods should be 12 mm in diameter and 6 m long. For transverse fastening, rods with a diameter of 10 mm are required. The transverse frame must be welded along the edges and in the central part; the remaining transverse rods are not welded, but tied with wire. In the process of assembling the frame, it is necessary to reduce welding work to a minimum. The fact is that the welded seam becomes less durable due to overheating, and when constructing a reinforced belt, this is unacceptable. Most of the parts should be assembled using tying wire.
The wire can be taken of the smallest thickness; its function is to maintain the integrity of the frame shape while pouring concrete. Using thick wire will not make the frame stronger, and installing such a structure will require much more money and effort.
When the two parts of the frame are ready, they are stacked, forming a small space between them. Then they are welded in the center and along the edges, forming a finished frame, which in cross-section has the shape of a square or rectangle. It is best to do this directly in the formwork, since the resulting part has quite a lot of weight.
There must be a distance of at least 5 cm between the reinforcement and each side of the structure. To raise the reinforcement above the horizontal surface, bricks or stones are placed under the frame.
When assembling parts into a solid reinforced belt, there is no need to use welding; you can simply make an overlap of 0.2 - 0.3 m between adjacent frame parts. The structure must lie level inside the formwork; to achieve this condition, it is necessary to use a building level.
Armopoyas – structural element building, located at the level of the top of the walls, under the floor slabs. The purpose of the armored belt is to ensure the joint operation of building structures during uneven deformations of wall materials. Also, the reinforcing belt provides a reliable connection between the walls of the building. Ensuring such a connection is necessary, since brickwork is an anisotropic material (the same can be said about masonry made from aerated blocks, foam blocks, expanded clay blocks, etc.), which cannot work equally in compression and tension.
It is necessary to clearly distinguish between the concepts of reinforced belt (armoshov), reinforced brick belt, monolithic belt. Armoshov consists of reinforcing bars arranged in one row, protected by a layer of c. p. solution. The thickness of such an armored seam (armoured belt) usually reaches 30 mm. Such a structural element is laid on top of the walls, under the support of the floor slabs. This type of armored belt should be provided on the first and last floors of the building, as well as every five floors throughout the entire height of the building.
Reinforced brick belt - a structural inclusion in brickwork made of monolithic reinforced concrete. Characteristics reinforced brick belt is as follows: it is installed at the ends of the floor slabs and not over the entire width of the wall. Between the ends of the floor slabs and along the perimeter of the building, reinforcement cages are installed and concreted.
Monolithic reinforced concrete belt. This structural element in configuration and location resembles an armored belt (armoshov), but, unlike it, it is reinforced not with one row of reinforcing bars, but with several rows, usually two, and has a height of 15 cm or more. The functional advantage of a monolithic belt is to distribute the load from the floor slabs onto the walls of the building, i.e. load-bearing and non-load-bearing load-bearing walls become loaded approximately equally and, due to this, give approximately equal load on the foundation, and also have a smaller difference in deformation under load than walls without a monolithic belt. It is very important to install a monolithic belt when building a house from aerated concrete blocks. IN low-rise construction a Mauerlat is installed on a monolithic belt rafter roof. Also, in addition to uniformly distributing the load between different walls, the monolithic belt protects the walls from the effects of local compression under the supports of the floor slabs (crushing), this is very important when building a house from aerated concrete and wood concrete blocks.
A fairly common design solution is to use a monolithic belt as a lintel over a window or doorway. In this case, the monolithic belt is calculated as a beam on two supports (a conventional reinforced belt cannot work as a lintel). In the general case, the beam appears to be rigidly clamped at the ends, however decisions made in the design scheme it is also necessary to ensure it structurally. If the opening is in the middle of an extended wall along which there is a monolithic belt, then design scheme a rigidly clamped beam will be ensured. However, if the opening is located too close to the edge of the wall and has a large width (approximately 10-15*H, where H is the height of the monolithic belt), then in this case it is worth calculating it as a simply supported beam. Of course, it is possible to rigidly fasten a monolithic belt in brickwork, but this will require a number of structural calculations and constructive measures during construction, so it is better to install it along its edges to strengthen the monolithic belt metal channels above the opening, which, by the way, will also serve as permanent formwork.
In the general case, the calculation of the armored belt is carried out under the action of loads from uneven settlements of the building. The reinforcement belt should prevent rotation of one part of the building relative to another or its parallel displacement during uneven precipitation.
When installing reinforcement and monolithic belts on brick walls, the question arises about the structure ventilation ducts, which will cross the armored belt through and through. Such solutions are very common in design practice, so that while maintaining the integrity of the working reinforcement (or part of the longitudinal rods) at the site of the ventilation duct, the operation of the reinforcement belt will not be disrupted.
In this article we will get acquainted with the LIRA program interface, and also calculate a beam on two supports with a uniformly distributed load. Lira program commands discussed in the lesson: Selecting a design feature Creating a new file Arranging nodes Creating bars Installing fasteners Assigning rigidities Applying loads Static calculation Reading calculation results Saving a calculation file. Watch the video tutorial for more details. […]
Armored belt or brickwork, which is better? Board formwork
A reinforced belt (reinforced belt) is a closed reinforced structure that follows the outline of the building walls and blocks their deformation as a result of load redistribution. That is, the armored belt allows you to avoid exposure to adverse weather conditions, when the house shrinks, soil settles, etc. The reinforcement can be made of reinforced concrete or brick. The armored belt acquires particular relevance when constructing houses from building materials that are not resistant to deformation.
Main functions of the armored belt
- strengthening walls;
Types of reinforced belts
Grillage.
Grillage
Base armored belt
Armobelt under the Mauerlat
So is it worth the risk and instead of making a full-fledged armored belt from concrete and reinforcement, make an armored belt from brick? In our opinion - no! Brick masonry is only slightly stronger than block masonry, even if it is reinforced. Two or three rows of bricks will not be able to evenly distribute the entire load along the walls. This will lead to
kupildoma.ru
Brick armored belt – PROBrick
A reinforced belt (reinforced belt) is a closed reinforced structure that follows the outline of the building walls and blocks their deformation as a result of load redistribution. That is, the armored belt allows you to avoid the formation of cracks from exposure to adverse weather conditions, when the house shrinks, soil subsidence, etc. The reinforcement can be made of reinforced concrete or brick. The armored belt acquires particular relevance when constructing houses from building materials that are not resistant to deformation.
Brick armored belt- This is ordinary masonry, reinforced with reinforcement. At first glance, this approach is simpler than pouring a full-fledged monolithic reinforced concrete belt with reinforcement. However, is this approach sufficient? Will such reinforced masonry replace a full-fledged armored belt? First, let's figure out what types of arm belts there are and what functions are assigned to them.
Main functions of the armored belt
- strengthening walls;
- ensures uniform distribution of loads;
- prevents the formation of cracks;
- promotes alignment brickwork;
- maintaining the integrity of the structure during shrinkage of the house.
Types of reinforced belts
It is customary to distinguish 4 types of reinforced belts.
Grillage.
Grillage- this is the lower, sub-foundation armored belt, which is the key to the strength of the entire building. In addition, it can connect columnar piles and pile foundation. The height of the grillage is from 30 to 50 cm, the width is 70 - 120 cm. For production, reinforcement with a thickness of 12 - 14 mm is used. For greater reliability and durability, concrete should cover the reinforcement frame by 5 cm on each side.
Base armored belt
It is laid around the entire perimeter external walls. If the ceiling is slabs, it is recommended to do it on all load-bearing walls. The main function of the base reinforced belt is to distribute loads on the foundation. Mesh reinforcement with a height of 20 - 40 cm is used;
Interfloor (unloading) belt
It is constructed to strengthen and tighten the walls, as well as to prevent the formation of cracks. In addition, it absorbs and distributes the load of the entire structure. Placed on all load-bearing walls;
Armobelt under the Mauerlat
An armored belt under the Mauerlat performs a number of useful functions: it allows you to securely fasten the Mauerlat itself, distributes the load from the roof, gables, rafter system, and levels the horizontal of the entire structure being erected. It is mounted along the perimeter of external walls, in some cases (with inclined rafters) - on the middle load-bearing wall. When creating a reinforcement frame, the studs are placed above it. A thread is made at the end of the rods, and corresponding holes are made in the Mauerlat. After the poured concrete has hardened and gained strength, a Mauerlat is installed on the studs and secured with bolts.
When manufacturing armored belts, special requirements are placed on the quality of concrete. It is recommended to use cement grade no lower than M200. The concrete mixture is poured at once, which will allow it to harden evenly and set well. For higher strength, concrete is periodically wetted.
Is it worth making an armored belt out of brick?
So is it worth the risk and instead of making a full-fledged armored belt from concrete and reinforcement, make an armored belt from brick? In our opinion - no! Brick masonry is only slightly stronger than block masonry, even if it is reinforced. Two or three rows of bricks will not be able to evenly distribute the entire load along the walls. This will result in some fragments and sections of the brickwork experiencing high blood pressure, compared to the rest of the wall, and this is dangerous due to the appearance of cracks and even complete destruction of the wall. Therefore, it would be right not to take risks and make full reinforcement with an armored belt made of reinforced concrete.
Read also:
www.kirpich.nnov.ru
Armobelt. What is it and how to do it
What is an armored belt?
A reinforced belt, also known as a monolithic belt or seismic belt, is a special design designed to solve two problems. First, distribute the load from what will be on top to what will be below. And, secondly, to connect the entire plane on which it is located into a single whole. Both a monolithic concrete armored belt and a reinforced brick one cope with load distribution. Both of them do an excellent job of distributing the load, say, from floor slabs to walls. If the task is also to connect the walls into a single whole, for example, from the bursting load of the roof rafters on the walls of the house, then a reinforced concrete belt is needed.
How to make an armored belt with your own hands
Now that we’ve figured out what an armored belt is, let’s find out how to make it with your own hands. With a brick armored belt, everything is simple. Typically, masonry is made of solid red brick of minimum grade M100 in several rows with reinforcement with masonry mesh. You can also reinforce the masonry with reinforcement with a diameter of 6-8 mm. With a concrete, monolithic armored belt, the situation is more complicated.
First you need to set up the formwork. This can be either wooden formwork or “tray” or permanent formwork, if we are talking about an armored belt on aerated concrete or foam concrete blocks. You can use factory U-blocks or make your own trays. To do this, it is not necessary to cut a U-block from a regular gas block. It is enough to make masonry from a thin gas block on the outside and inside. The space between these blocks can be insulated with extruded polystyrene.
After you have made the formwork, a reinforcement frame is placed inside the tray.
Sufficient reinforcement for an armored belt measuring 200 by 200 mm is a frame of 4 threads of reinforcement with a diameter of 12 mm (two on top and bottom), fastened with transverse clamps with a diameter of 6-8 mm every 30-50 cm.
The standard overlap of reinforcement should be 30-40 diameters. That is, if you are laying 12 mm reinforcement, then when building it up, you need to make an overlap of about 40 cm.
In the corners, reinforcement is necessary fold over so that the corner is connected by solid reinforcement.
It is advisable to place the frame made of reinforcement on plastic clamps of the thickness of the protective layer of concrete. And put the clamps on the vertical clamps. If there are no factory fixings for the protective layer, you can use pieces of stone, brick, etc.
Pins under the Mauerlat or pieces of reinforcement are attached to the reinforcement frame for subsequent fixation of the floor slabs.
Now you can proceed directly to pouring the reinforced belt with concrete.
If you will be pouring purchased concrete, choose the M200-M250 brand. This grade of strength is absolutely enough for private construction.
If you plan to prepare concrete for pouring the armored belt yourself, then use universal recipe proportions of concrete for the armored belt: 1 part cement grade 500, 2 parts sand, 4 parts crushed stone.
You can also use one of our construction calculators to calculate the composition of concrete. Don't forget to add concrete plasticizer to the mix. This will make the filling more convenient for you, and the resulting armored belt more durable.
After pouring, cover the armored belt with film to prevent sudden drying. For the same purpose, wet the concrete for the first 2-3 days.
The armored belt will be ready for loading in a week. Full maturation of concrete will be completed 28 days after pouring. 
The most frequently asked questions on the topic of reinforced belts.
In what cases is an armored belt needed?
A monolithic reinforced concrete belt is required:
- on a block foundation
- on walls made of aerated concrete, foam blocks, etc. under hollow slabs and wooden beams overlaps (to prevent squeezing). Here the armored belt can be brick
- under the Mauerlat on the roof, the design of which assumes a spacer load on this same Mauerlat
Is it possible to fill the armored belt in winter, in cold weather?
Filling an armored belt in winter is a questionable task. However, if you really need to fill it in the cold season, take all measures to protect the concrete. Add special anti-frost additives to concrete. Use as much as possible less water for mixing concrete. After pouring, be sure to cover the armored belt to protect from the cold. For example, sawdust. IN minus temperature, use a special heating cable. It is sold in any construction supermarket.
What is the minimum thickness, height, width, size of the armored belt?
The minimum size of the armored belt is 150 by 150 mm. But not less than the width of the support of the slabs or floor beams.
The armored belt freezes, what should I do?
If you or your workers forgot to insulate the armored belt before pouring, then you will have to insulate it now. The armored belt is insulated from the outside.
Condensation on the armored belt. The armored belt is sweating. What to do?
Insulate. Other options: increase the room temperature, reduce the room humidity.
Is it possible to fill the armored belt in parts?
Can. To do this, make a bevel at the junction. And the concrete doesn't have to be smooth.
Video on the topic of reinforced belt
o-remonte.com
DIY armor belt for a brick wall
Do-it-yourself armored belt for a wall made of aerated concrete or brick
During the process of building a house, at certain stages questions may arise such as: does it make sense to make a reinforced belt, how many similar belts should the structure have, how to make it correctly and what materials are best used for this?
An armored belt is a monolithic closed reinforced concrete strip that follows the contour of the walls.
List of items that are needed:
- concrete grade 200;
- rods;
- excavator;
- sand or granulated slag;
- fittings;
- wire.
What is an armored belt for and where is it installed?
Grillage is the upper part of a pile foundation that distributes the load onto the load-bearing elements of the building.
First of all, you need to understand what a reinforced belt is and why it needs to be made. The reinforced belt is a layer of reinforced concrete, which is located along all the external walls of the building completely along the entire perimeter. Its task is to increase the strength of load-bearing external walls made of aerated concrete or brick and maintain integrity during the process of soil subsidence. During construction, several such belts should be used.
The first reinforced belt is also called a grillage. In the process of its manufacture, it is necessary to pour concrete into a trench that was dug under
stroy-bloks.ru
How to make an armored belt - types of belts and methods of filling them (+ diagrams)
They call it an armored belt reinforced concrete structure, which is designed to strengthen the walls of the house. This is necessary to protect the walls from loads arising under the influence of external/ internal factors. External factors include wind exposure, terrain slope/hilliness, floating soil and seismic activity of the earth. The list of internal factors includes all household construction tools, used for interior decoration Houses. If you make an armored belt incorrectly, then due to these phenomena the walls will simply crack, and what’s even worse, they will corrode. In view of this, it is very important to be aware of how to make an armored belt. The types, purpose and method of installation of the armored belt will be discussed in this article.
Kinds
There are 4 types of armored belt:
- grillage;
- basement;
- interfloor;
- under the Mauerlat.
Tools and materials
Before starting work, you should prepare the following tools/materials:
- Fittings.
- Cement.
- Sand.
- Crushed stone.
- Wire for tying reinforcement.
- Boards.
- Self-tapping screws.
- Brick.
- Shovel.
- Concrete mixer.
- Crowbar/crowbar.
- Welding machine.
To ensure that all the work you perform is done with high quality, we suggest that you familiarize yourself with the techniques for manufacturing reinforced mesh/framework and formwork.
Manufacturing of reinforcing mesh/frame
In order for the reinforced belt to be of high quality, and therefore the house to be reliable, you need to know how to properly make the reinforced mesh/frame. The connection of the reinforcement bars to each other is carried out using a knitting wire, and not a welding seam. This is due to the fact that during welding, the area near the seam being made overheats, which leads to a weakening of the strength of the reinforcement. But you can’t do without welding seams when making mesh. The middle and ends of the frame are welded, while the remaining connecting nodes are tied together.
Laid frame in armored belt
The rods are fastened to fix the reinforcement in the required position when pouring concrete. For these purposes, thin wire is used; the strength of the mesh/frame does not depend on it.
For the manufacture of armored belts, only ribbed rods are used. Concrete clings to the ribs, which helps to increase the load-bearing capacity of the structure. Such a belt can work in tension.
To make a frame, take 2 wires 12 mm thick and 6 m long, while for transverse reinforcement you will need rods 10 mm thick. The transverse reinforcement should be welded in the center and edges. The rest of the rods are simply knitted. After making two meshes, hang them so that a gap is formed. Weld them from the edges and in the center. This way you will have a frame. There is no need to weld the frames to make the belt. They are laid with an overlap of 0.2–0.3 m.
Formwork
Installation and fastening of formwork is carried out using several methods. To install wooden panels, you need to pass anchors through them and install plugs on them using electric welding. The purpose of these actions is to fix the formwork in such a way that it is not squeezed out under the weight of the concrete.
To secure the formwork when pouring interfloor armored belt A simpler method is often used. A screw with a diameter of 6 mm and a length of 10 cm should be fixed to the bottom of the shield. The distance between them is 0.7 m. So, attach the wooden shield to the wall, drill a hole through it, insert a mushroom into it and drive the screw.
The hole in the shield should be slightly larger than 6 mm in diameter. This is necessary in order to easily install the fungus.
Wooden formwork
The upper part of the formwork is also secured with quick installation. But in this case, you should screw in a self-tapping screw, not a screw. So, make a hole in the face brick. Then drive the reinforcement into it. If the brick is solid, then the situation is simpler - just drive a nail/reinforcement into the vertical seam. Tighten the self-tapping screw and reinforcement with binding wire. The distance between fastening elements is 1–1.2 m. Such fastening is capable of withstanding the upcoming loads.
After the armored belt has hardened, the formwork can be removed using a crowbar/nail puller. In the warm season, concrete sets within a day. In this case, the dismantling of the formwork can be carried out the next day. During the cold season, this procedure is carried out a few days later.
Grillage
Initially, you should determine the depth of the foundation. This parameter depends on the type of soil, the depth of its freezing, as well as the depth of groundwater. Then you should dig a trench around the perimeter of the future house. This can be done manually, which is long and tedious, or with the help of an excavator, which is quick and efficient, but entails additional costs.
After special equipment is used, the bottom and walls of the trench should be leveled to solid ground. The surface should be as hard and smooth as possible.
Now you need to form a sand cushion, the height of which should be 50–100 mm. If it is necessary to backfill sand more than 100 mm, it must be mixed with crushed stone. This activity may be necessary to level the bottom of the trench. Another way to level the bottom is to pour concrete.
Making a frame for a grillage
After filling the sand cushion, it must be compacted. To complete the task faster, pour water on the sand.
Then the reinforcement should be laid. During construction in normal conditions you need to use reinforcement of 4–5 cores, the diameter of each rod should be 10–12 mm. It is important that when pouring the grillage for the foundation, the reinforcement does not touch the base. It must be recessed in concrete. Thus, the metal will be protected from corrosion. To achieve this, the reinforcing mesh should be raised above the sand cushion, placing brick halves under it.
Strip foundation grillage
If you are building a house on heaving soil or where the groundwater level is high, then the grillage should be made more durable. For this instead reinforcing mesh reinforcement cage should be used. He imagines 2 meshes consisting of 4 wires with a diameter of 12 mm. They should be laid below and above the armored belt. Granular slag is used as a base instead of a sand cushion. Its advantage over sand is that over time, granulated slag turns into concrete.
To make the mesh, a knitting wire is used rather than a welding seam.
For the grillage, M200 concrete should be used. To ensure that the filling height corresponds to the specified value, install a beacon in the trench - a metal peg equal in length to the height of the grillage. It will serve as your guide.
Base armored belt
Before erecting walls, a basement reinforced belt should be poured onto the foundation. It must be poured along the perimeter of the building along the external walls, but this cannot be done along the internal load-bearing walls. The base armored belt serves as additional reinforcement of the structure. If you have filled the grillage with high quality, then the plinth belt can be made less durable. The height of the armored belt is 20–40 cm, concrete M200 and higher is used. The thickness of two-core reinforcing bars is 10–12 mm. The reinforcement is laid in one layer.
If you need to strengthen the base belt, then use reinforcement of greater thickness or install more conductors. Another option is to lay the reinforced mesh in 2 layers.
Formwork for base armored belt
The thickness of the basement and external walls is the same. It ranges from 510 to 610 mm. When pouring the base armored belt, you can do without formwork, replacing it with brickwork. To do this, you need to make half-brick masonry on both sides of the wall. You can fill the resulting void with concrete after placing reinforcement in it.
In the absence of a grillage, it is useless to make a base armored belt. Some craftsmen, having decided to save on the grillage, strengthen the base belt, using reinforcement of a larger diameter, which supposedly improves the load-bearing capacity of the house. In fact, such a decision is unreasonable.
The grillage is the foundation of the house, and the plinth belt is an addition or strengthening of the load-bearing capabilities of the reinforced belt for the foundation. Collaboration grillage and plinth belt guarantee a reliable foundation even on heaving soils and with high level occurrence of groundwater.
Interfloor
An armored belt must also be made between the wall and the floor slabs. It is poured along external walls with a height of 0.2 to 0.4 m. Interfloor armored belt allows you to save on door/window lintels. They can be made small and with a minimum of reinforcement. Thus, the load on the structure will be distributed evenly.
If an armored belt is installed on walls made of poorly load-bearing material, the load from the floor slabs will be distributed evenly along the entire length of the walls, which will have a beneficial effect on their strength characteristics.
Formwork for interfloor reinforced belt
Reinforcement of the interfloor belt is carried out with a mesh of ribbed reinforcing bars 10–12 mm thick in 2 cores. If the thickness of the walls varies between 510–610 mm, then double-sided brickwork can be used as formwork, as for the base belt. But at the same time, backing bricks should be used for internal masonry, and facing bricks for external masonry. In this case, the armored belt will have a width of 260 mm. If the walls are thinner, the backing brick should be laid on edge or wooden formwork should be used instead, and the facing brick should be laid on the outside in the same way as in the previous case.
Under the Mauerlat
The armored belt can be poured under the Mauerlat only after the glue/mortar for masonry walls has hardened. The technology used to lay the reinforced belt on aerated concrete differs in the formwork design, but we will talk about this a little later. The production of wooden formwork is carried out according to a scheme already familiar to you. Concrete is prepared according to the following formula: 2.8 parts sand to 1 part cement and 4.8 parts crushed stone. Thus, you will get M400 concrete.
After filling, eliminate any remaining air bubbles in the mixture. To accomplish these tasks, use a construction vibrator or poke a rod into the liquid mass.
Mounting the Mauerlat
When constructing a monolithic armored belt, the rules for fastening the Mauerlat must be observed. During the installation of the reinforcement frame, vertical sections should be removed from it to the height specified in the project. The reinforcement bars should rise above the reinforced belt by the thickness of the Mauerlat + 4 cm. It is necessary to make through holes, equal to the diameter of the reinforcement, and threads should be cut at its ends. So, you will get a reliable mount, which will give you the opportunity to carry out high-quality installation roofs of any configuration.
Reinforced belt for aerated concrete
Aerated concrete is an alternative to brick, which has high thermal insulation qualities along with low cost. Aerated concrete blocks inferior to brick in strength. If when installing an armored belt on brick walls it is not necessary to pour concrete, since the reinforcement is laid during the laying process, then with aerated concrete things are different. How to make an armored belt on wooden formwork has already been discussed above, so in this subsection we will look at how to make a reinforced belt from U-shaped aerated concrete blocks D500. Although it is worth noting immediately that this technology is more expensive.
In this case, everything is extremely simple. Place the blocks on the wall as usual. Then reinforce their central part, and then fill it with concrete. Thus, the walls of your home will be more durable and reliable.
If you still have questions on the topic, then ask them to a specialist working on the site. If necessary, you can consult with our expert about filling the armored belt. Eat personal experience? Share it with us and our readers, write comments on the article.
Video
You can learn how to make an armored belt for a house made of aerated concrete from the video:
kakpravilnosdelat.ru
Do-it-yourself reinforced belt for Mauerlat and floor slabs
Table of contents:
- Why do you need an armored belt?
- Fastening formwork and reinforcement frame
- Armopoys of a brick house
The armored belt protects the house from deforming loads. It is especially required for buildings that are built from porous materials. For example, brick, foam and gas blocks. The house is under such pressure that the masonry may break and “crawl” under the influence internal forces. It is also exposed to external factors. Unloading belts are installed at different levels of the building. For example, foundation, basement, between floors, as well as an armored belt under the Mauerlat, which takes on the weight of the roof. What kind of reinforcing structures are required depends on the material of the walls and the load to which they will be subjected.
Why do you need an armored belt?
Difficult soils lead to uneven shrinkage of the building. In addition, wind loads and temperature changes lead over time to distortion of the structure and its destruction. All this requires strengthening the load-bearing walls. Another important reason is the use of materials of different hardness. For example, interfloor reinforced concrete slabs are placed on aerated concrete walls, but reliable fastening directly to the blocks is impossible.
In such cases, an armored belt must be installed under the floor slabs, which is located on the line of their support on the facade. Likewise, the roofing pie cannot be mounted directly on the blocks. A heavy roof will press down and sideways on them, which will eventually lead to cracks. The fact is that the blocks tolerate a uniform rather than a point load well, therefore, when installing a beam for the upper trim, it is necessary to install a distribution belt.
It is laid on the top row of blocks and combines the roof and facade into a single strong structure. Thus, the load from roofing system takes on an armored belt under the Mauerlat, which becomes a kind of intermediary between the blocks and the timber for attaching the rafters. In addition to this type of reinforced concrete belts, a foundation reinforcing system is installed (inside the foundation itself) and a basement reinforcement system, which is located on the foundation (usually on a strip foundation).
Important: a house made of aerated blocks must be reinforced between floors before laying floor slabs and after construction top floor before installing the roof.
How does the armored belt work?
The structure is located along the perimeter of the building without interruption. It is a monolith running along the contour of the walls. Its device is similar to strip foundation, but it is supported by the erected walls of the facade and internal load-bearing partitions. In low-rise construction, you can make an armored belt with your own hands, provided that ready-made concrete is delivered to the top. It is also necessary to ensure that the entire structure is filled with it quickly so that it does not begin to harden unevenly.
How to make a reinforcing belt correctly?
Work begins after the mortar or adhesive for laying the wall material has hardened. It should be noted that for gas blocks it is better to use a special glue that can be used to make a 3 mm thick seam without losing the quality characteristics of the facade. The technology used to lay the armored belt for aerated concrete differs in the design of the formwork. Wooden shields are used for it ( standard option) or special U-blocks brand D500. The second method is more preferable.
The blocks represent permanent formwork With good parameters heat saving. This means that concrete will not turn into one large cold bridge and will not require additional insulation. For removable wooden formwork, use panels made of 2 cm thick boards, which are pre-assembled on the ground.
How to securely attach the formwork?
An important point is the fastening of removable formwork. It is stitched through with reinforcement, and then iron knobs are welded to the rods from the outside. Also, the shields are tied together with wire and knocked down with boards, placing them on top. Reliable installation of formwork is important if the solution will be supplied through a pressure hose from a cement truck. If you do it yourself, you lift the cement with buckets. In this case, there is less risk that the formwork will break under the pressure of concrete.
Rebar frame
After installing the formwork, a frame is made from longitudinal rods d = 12 mm in an amount of at least 3 lines. For crossbars, use rods of the same thickness if they are constructing an armored belt for floor slabs between floors. But if it is installed under the Mauerlat, the reinforcement can be taken thinner (8-10 mm). The intersection points are knitted with wire. It should be noted that it is necessary to make 2 contours of the frame from rods.
Concrete is prepared according to the formula:
- sand 2.8 parts,
- cement 1 part,
- crushed stone 4.8 parts.
This ratio of ingredients allows you to obtain concrete grade M400. After pouring the solution, any remaining air bubbles in the mixture should be eliminated. To do this, use a construction vibrator or hit the concrete with a rod, pierce the still liquid mass to allow air to escape.
How to properly attach the Mauerlat?
It should be said that the monolithic device of the armored belt requires compliance with the rules for fastening the Mauerlat. Even during the installation of the frame, vertical sections of reinforcement are removed from it to the design height. They should rise above the armored belt by the thickness of the Mauerlat + 4 cm. Threads are cut at the ends of these sections, and through holes of the same diameter are made in the timber in appropriate places. Thus, a reliable fastening is created that corresponds to a bolt and nut tie, which will allow you to reliably install a roof with any design features.
Armopoys of a brick house
For brick walls, you can make a simplified version of reinforcement with reinforcement. Instead of a monolithic one, an armored belt is made of bricks directly during laying. Depending on the load, the façade and internal load-bearing walls are reinforced with reinforcement or a special mesh. This is done every 4 rows. IN in this case there is no need to install formwork, since the rods are laid directly on the brick during the construction of the row. If you take a mesh, its thickness should be from 5 mm.
osnovam.ru
Is armored belt needed for floors or not?
The question is whether you need an armored belt or not if you are building a house from blocks, I was puzzled by this question when I came across a video clip in which someone was building a house from large-format ceramic blocks and under the floor slabs he began to lay bricks from ordinary solid bricks, raised them into two rows and onto it laid the slabs. His main argument for constructing an armored belt was that he was not confident in the strength of the Porotherm block. I became interested and turned to the documentation of the manufacturer of the Porotherm block. From these documents it turned out that from 44 it is possible to build buildings up to the 8th floor and no installation of reinforcing belts under the floors is required. I didn’t stop there and decided to search the Internet for photos and videos of houses made from large-format blocks.
My searches were successful and I found a video and photo in which a block was breaking off under hollow-core floor slabs, the block was destroyed along its entire height or from the top to a depth of 2cm to 5cm, this undoubtedly alarmed me, and I assumed that this was happening in places greatest tension. In practice, once a crack appears on a block, it usually occurs when a single impact is applied to it, which is why when laying blocks of warm ceramics you need to use soft rubber mallets. It immediately became clear that when laying the slabs, large pebbles could get into the mortar and when the slab was lowered, they had a point effect on the block, which led to its destruction. Having understood what was happening with the block, I decided that there was no need to make a massive armored belt, which would also be a completely unnecessary cold bridge. It is clear that it is enough to first make a screed, and not for the entire thickness of the wall, but only to the depth of support of the floor slab and a thickness of 10mm-15mm. This is also convenient because the screed can be made to be level and the slabs will be easier and more evenly placed relative to each other. When laying the slab, there is a high probability that the mortar will fall into the honeycombs of the block and the slab will not lie flat; the screed will prevent the mortar from falling into the block.
In addition, in order to document whether an armored belt is needed under the floors for porotherms or not, I will provide drawings constructive solutions on the installation of floors from hollow core slabs and monolithic floors different thicknesses for walls made of Porotherm 38, 44, 51, the solution for monolithic floors can also be used for the installation of floors from PNO slabs. The manufacturer Porotem ordered design calculations from the Scientific Research Institute of Building Structures; structural calculations were carried out for 6, 7 storey buildings from porotherm. I would like to make just a few of my own comments on two nodes, namely, supporting the slab on the masonry mesh directly through the mortar, the result can be squeezing the mortar out and into the block, resulting in the slab lying not on the mortar, but on the mesh, this is not very good for the block because the load on the block from the slab will not be evenly distributed and the noise from the ceiling will be more strongly transmitted to the wall. The second point is the use facing bricks to compensate for height in 160mm thick floors, it is better to replace it with solid brick.
There is one very important point for floors, which must be taken into account at the design stage, the maximum and nominal length of the floor, which was calculated by one construction institute which was tasked with calculating load-bearing capacity ceramic block porotherms and prepare technical and structural solutions for the installation of certain components of the building structure. Calculations have shown that the length of the floor span is limited and is nominally 6 meters, with a maximum of 7 meters.