Prefabricated glass-type foundation. Construction of glass-type foundations, installation of columns in glasses
The foundation is the foundation on which any structure is built. It is the main element of the house, its main task is to transfer and correctly distribute the load from the mass of the building to the ground. Any foundation for a house is subject to generally accepted construction standards, the changes relate only to the chosen technology and the state of the soil at the place of its construction.
In private low-rise construction, slab, pile, tape types of foundations are in demand. The following factors influence their choice: the condition of the soil, the depth of groundwater, the terrain, the depth of soil freezing, the architectural features of the house.
Determining the condition of the soil
The foundation of any building is its foundation. It determines the life of the entire house. Any private developer, starting the construction of a building, is wondering how to choose the type of foundation. Everyone wants the base to organically fit his future home.
If the building is being built in a residential village, then it is worth studying on what grounds the nearby houses were built. By comparing them and comparing all the factors, you can decide which choice to follow.
The choice of foundation type depends on the condition of the soil and its type. Each type of soil has its own individual properties and gives a different draft during the construction of one or another type of foundation.
Coarse-grained sandy soils are considered ideal. Houses built on them give a uniform draft, and the foundations serve as a solid support for the building. On such soils, buildings can be erected on any foundations.
Soils consisting of clay and sand take the next place in terms of reliability. They hold buildings well, but the sole of the foundation on such soils must be located below its freezing point, then nothing will threaten the foundation.
The most inconvenient and problematic soils are peat. To build a house on them, you have to dig a pit and prepare an impressive sand cushion, and this leads to an increase in the cost of the entire building.
It is possible to protect the foundation from groundwater that freezes in winter by equipping the sole of the base below this level.
Foundation types
The types of foundations and their main characteristics are described below. When building foundations, you must adhere to these rules and tips.
The most popular and quickly built is the type of foundation tape. Visually, it represents a strip of concrete, which, together with load-bearing walls, repeats the perimeter of the house. Usually, buildings of concrete and brick are built on such a foundation. The strip foundation is used in the construction of private houses.
The pillar foundation is characterized by efficiency. It is especially well suited for the construction of small summer wooden houses on heaving soils. The downside is the lack of basements in such buildings.
One of the varieties of pillar foundations are pile foundations. They are great for building houses on weak and peaty soils, but they are distinguished by a high manufacturing price.
The foundation of the glass type is one of the varieties of the columnar base. It is highly durable and acts as a base cushion.
Quality control of works and materials
When performing work, you need to constantly monitor their quality. All knots of the carcass reinforcement ligament must be securely locked. Formwork fastening must be strong and reliable so that concrete spill does not occur.
After creating the foundation, you need to wait a month, during which time the concrete will gain the necessary strength, and only then proceed with the construction of the main building.
Concrete must be of excellent quality, when pouring it, in order to avoid the occurrence of air bubbles in it, a vibrator should be used.
Characteristics of tape bases
The most popular and most commonly used are tape bases. They are in demand in the construction of private houses. The type of foundation tape is a concrete strip that follows the contour of the building. Such foundations are divided into several types according to their design.
If the depth of the strip foundation corresponds to the level of soil freezing, then such a foundation is the most durable, but at the same time also expensive. The strip foundation can be monolithic, in which case the concrete is poured at the construction site, or assembled from special foundation blocks. Their delivery to the site makes construction significantly more expensive.
The width of the tape base should not be less than the thickness of the bearing wall of the building. When building on soft soils, a wider base pad is required.
Construction of the strip base
Such foundations for the house are made in different ways. With the help of an excavator, a pit is dug in those places where the tape will be located, sand and gravel are added, which are then rammed. If a monolithic foundation is being erected, then the formwork is mounted, a reinforced frame is assembled and concrete is poured. During the construction of the prefabricated base, blocks are installed, then the walls are poured from the outside. Usually the resulting interior is used as a basement.
Tape types of foundations made in other ways are less expensive, but exclude the possibility of building a basement. A trench more than 40 cm wide is dug, formwork and reinforcement are placed in it, everything is poured with concrete mortar.
If the trenches are already prepared for 40 cm, then concrete is poured into them without formwork, but this method cannot guarantee the high quality of the strip foundation.
The high cost of buried strip foundations is the main disadvantage of such foundations. Therefore, shallow foundations are often erected. They are above the freezing level of the soil. It is believed that the foundation rises and falls evenly during the heaving of the soil. These types of foundations are well suited for the construction of not too heavy wooden houses, buildings built according to the frame construction method.
columnar base
A relatively inexpensive, well-proven on difficult soils, a columnar foundation is suitable for the construction of light wooden structures. The technology for building such a foundation is simple. Wells are drilled in the soil, in which reinforcement is placed and poured with cement. To prevent concrete milk from being absorbed into the walls of the wells, it is necessary to waterproof them. This can be done with the help of ruberoid.
Columnar foundations are divided into flood and driven.
The first are made by pouring concrete into a well prepared using a hand drill or special equipment. Usually the depth of the well is below the freezing point of the soil.
The second are piles that are driven in with special equipment, which leads to an increase in the cost of construction.
The base posts must be of such length that they can reach the bearing layers of the soil. If this cannot be done on the site, then hanging piles are used, on which the entire load falls on the adhesion of the side walls of the pile to the soil. In the manufacture of filler piles, the presence of reinforcement is mandatory. Columnar piles with a grillage made using the monolithic strip foundation method serve as a reliable foundation for low-rise houses.
Columnar foundations include pile foundations. They are widely used in industrial and private construction.
Types of pile foundations depend on the location of the piles.
- Single piles are used in the construction of light wooden houses.
- Tape - for the construction of large buildings.
- Pile bushes are used for the construction of columns, free-standing supports.
- Pile fields are used in the construction of multi-storey buildings.
glass base
There are different types of foundations for a house.
The glass-type foundation serves as the basis for columns that are made of metal or reinforced concrete. It belongs to the varieties of the columnar base.
The glass-type foundation for columns is characterized by high strength, reliability and long service life. It performs the same role as a pillow in a tape base, but there are differences. The main thing: the pillar itself is higher than the glass and is not poured with concrete.
The glass-type foundation for columns is made with reinforced reinforcement, so it is particularly durable and long-lived. When carrying out private construction, this type of foundation is not used due to the high cost. They are used in the construction of bridges, large objects.
glass base
A monolithic glass-type foundation cannot be used on heaving soils and soils subject to subsidence.
When performing the installation of columns, they are installed in a special glass, and then securely fixed.
In the manufacture of glass bases, the accepted norms and rules, which are enshrined in GOST, must be followed:
- Grade 200 concrete used for the manufacture of glass blocks must have water resistance B2.
- Transportation of blocks to the construction site is carried out only when checking the corresponding strength index.
- The glass block is made with the provided increased reinforcement.
- Reinforcement bars should not stick out of the finished block, such a product is considered defective and cannot be used in construction.
- Concrete blocks should not have cracks larger than 0.1 mm.
- The hinges intended for installation are carefully cut off after it is completed.
Glass foundations are used in the construction of the foundations of large industrial facilities, columns, bridges.
The advantages of the glass base include ease of installation, saving time in its arrangement.
The disadvantages include the mandatory use of special equipment, high cost, the need for transportation from the manufacturer to the construction site.
Mounting
Installation of glass bases is carried out by specialists and takes place in several stages.
Before installation, the surface is prepared. It is leveled and freed from all objects interfering with the work.
Then recesses are prepared, the bottom of which is covered with gravel and carefully rammed, only after all these works are completed, glass foundation blocks are installed.
During the installation of blocks, their correct location is controlled using geodetic instruments. After installing the glasses, you need to ensure that dirt and debris do not get into them.
Despite its cost, arranging the foundation with the help of glass blocks significantly reduces the cash costs for the construction of the foundation. Manufacturers produce glass blocks of various sizes, weights and costs.
slab base
The slab foundation consists of a monolithic base made of reinforced concrete, located under the entire building. It is recommended to build it during the construction of low-rise private houses, where it will serve as the base of the floor.
Any type of monolithic foundations is characterized by tangible financial investments that go to pay for land work, the cost of concrete, reinforcement, formwork parts.
Construction of a slab base
The slab type of foundation begins with digging a foundation pit. Further, its bottom, the walls are leveled, compacted. At the bottom, a pillow is constructed, consisting of sand and a layer of gravel. All this is covered with a waterproofing layer, on top of which a thin concrete screed is made. After it dries, reinforcement is mounted, the entire prepared pit is poured with concrete. The result is a homogeneous monolithic reinforced concrete slab.
Such bases are included in the types of foundations for the house and are not buried. They are located at a depth of 40 cm. Rigid reinforcement of the entire area of the slab allows it to cope with the loads that arise when the soil moves.
These types of foundations can be safely used to build houses on any soil and with different occurrences of groundwater. A solid monolithic reinforced concrete slab is not afraid of any soil displacement. On it you can build a two-story house from any materials.
On what soils can a slab base be equipped?
The slab foundation is the most versatile type of foundation. It is made of monolithic reinforced concrete and has reinforced reinforcement located over the entire area. Slab bases are being built:
- To eliminate and reduce the draft of the building.
- Due to technological factors, when the construction plan requires a monolithic slab under the entire structure.
The device of a solid monolithic foundation requires a large amount of concrete, reinforcement, so it is better to build them when building small private houses, when it is not necessary to build a basement, and the foundation itself serves as the floor of the building.
Large footprint reduces ground pressure.
A solid monolithic slab and the structure above it adequately respond to the external force and the possible movement of the soil. When building a house on such a foundation, it is not necessary to spend money on various expensive measures that protect the building from soil movement.
When erecting a slab base, the consumption of building materials is reduced: concrete by 30%, labor costs are reduced by 40%, and the entire cost of such a base is 50% less than the cost of building a buried version.
In cold Russian regions, it is better to build houses on a monolithic frost-resistant slab base. Such a foundation is a reinforced concrete slab 25 cm thick, buried 40 cm into the ground. Its edges are thicker, foam is used as protection against frost. Types of such a base are successfully used in the Scandinavian countries, where the climate is very similar to the Russian one.
The heat of the house heats the monolithic base slab and moves the soil freezing line up, it is located along the perimeter of the building. This once again confirms the rule that the level of soil freezing increases at any base if the building is heated and equipped with frost-resistant insulation located at ground level.
This insulation eliminates heat losses and redistributes them through a monolithic slab into the soil under the base of the building.
Developers of private houses should be aware that the savings in the construction of frost-resistant foundations are less than in the construction of traditional ones. These expenses account for 3% of the total financial investment required for the construction of the building.
If you can not do without a basement, then they make a recessed monolithic foundation under the entire structure. In such buildings, the load is distributed evenly over the entire base slab, the settlement of the house occurs evenly, and the monolithic reinforced concrete slab protects the basement from groundwater.
Slab foundations are built on soft soils, thereby ensuring a uniform distribution of large loads on the foundation. Experienced builders claim that such foundations have proven their advantage over other types of foundations in the construction of private houses with basements.
The construction of basements on a monolithic foundation requires the installation of hydroprotection on it. If its scheme is executed correctly, then the basement will be reliably protected from groundwater.
Results
From this material, you learned about what types of bases exist, what advantages and disadvantages they have. What to choose for your home depends entirely on your desire, financial capabilities and many related factors.
Reinforced concrete foundations of glass type
When installing prefabricated frames of basements of one-story industrial buildings, in particular, for installing frame columns of condensing recessed rooms of engine rooms located in the main buildings of thermal and nuclear power plants, glass-type foundations of the FZh-1m, FZh18-m-2 brands are used. These foundations are intended for installation of prefabricated reinforced concrete columns with a cross section from 300×300 mm to 700×500 mm. Drawings and requirements for glass-type foundations FZh-1m, FZh18-m-2 were developed in R.Ch. 71159-S.
For the production of glass-type foundations of grades FZh-1m, FZh18-m-2, heavy concrete of class B15 in terms of compressive strength, F50 frost resistance and water resistance from W2 to W8 is used. The FZh-1m foundation has dimensions in terms of 0.9 × 0.9 m, a height of 1.1 m and a mass of 1.8 tons, the size of the glass in the upper section is 550 × 500 mm, and the depth is 800 mm. The foundation of FZh 18-m-2 is 2.5 × 2.5 m in plan, 1.75 m high and has a mass of 9.5 tons. The size of the glass is 900×700 mm and its depth is 900 mm.
Installation of glass-type foundations is carried out on a sand bed on a natural basis or on a cement-sand mortar on the upper edge of a monolithic grillage with a pile foundation.
Glass type foundations
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Organization of work of workers for the installation of prefabricated elements
To ensure the execution of works on the construction of the foundation in the shortest possible time and with the proper quality, the foreman before the start of work must:
study working drawings;
distribute the task among the workers, explaining to them the technology of work;
prepare the necessary number of tools and fixtures required for the production of work;
determine the need for materials and products;
determine the scope of work and the rearrangement of workers in case of forced downtime.
The correct placement of workers for individual processes and operations, the preparedness of the scope of work, compliance with the technological regime of work and the implementation of other necessary measures will contribute to successful work and the achievement of the tasks set. For the installation of prefabricated strip foundations, it will be enough to include four people in the link. The link of workers conducting the installation of the foundation must be provided with the following tools:
trowels - 2 pcs.;
hand chisels - 2 pcs.;
mounting crowbars - 2 pcs.;
hammers-cams - 2 pcs.;
carpenter's ax - 1 pc.;
mooring cord - 40 m;
plumb line 400 g - 1 pc.;
level - 1 piece;
steel tape measure - 1 pc.;
shovel shovel - 2 pcs.;
bayonet shovel - 1 pc.
In addition, slings are required for lifting blocks, boxes with a capacity of 0.25 -0.5 m3 for mortar, wedges for aligning blocks, stakes for setting out, inventory portable scaffolding, a ladder for descending into the pit (trench).
Foundations
When constructing foundations, one should be guided by the following regulatory documents: SNiP 2.02.01-83. Foundations of buildings and structures, SNiP 2.02.03-85. Pile foundations, SNiP 3.02.01-87. Earthworks, bases and foundations, SP: 50-102-2003. Design and installation of pile foundations, MGSN 2.07-97. Foundations, foundations and underground structures.
The foundations are the supporting part of the building and are designed to transfer the load from the overlying structures to the base (soil). The operational qualities of the building, its solidity and durability largely depend on the reliable operation of the foundations. The structures, material and depth of foundations depend on the magnitude and nature of the loads acting on the foundation, on the capital size and design features of the building (presence of a basement, foundations of adjacent structures, etc.), as well as on the natural conditions of the construction site (depth of soil freezing, nature their occurrence, the presence of groundwater, etc.).
The sole of the foundation should be below the freezing depth of the soil, while for sandy loam and fine and dusty sands, the standard freezing depths are taken with a coefficient of 1.2.
The foundations of internal walls, columns and other parts in heated buildings in the absence of basements are laid to a shallower depth, but not less than 0.5 m from the ground, with their indispensable protection from freezing during the construction period.
If the groundwater level is high and the freezing depth captures them, choose one of the options:
1. take this factor into account when choosing a reliable foundation option, regardless of the increase in construction estimates;
2. carry out work, if possible, to ensure a guaranteed lowering of the groundwater level.
The construction of foundations on water-bearing sandy or sandy loamy soils with a free water horizon above the sole mark should be accompanied by a decrease in the groundwater level to a mark of 0.5 m below the bottom of the pit.
Depending on the form and method of resting on the ground, the foundations are divided into columnar, pile, tape and slab. Foundations can be built from ready-made prefabricated concrete and reinforced concrete products, from monolithic concrete and reinforced concrete, combined - prefabricated-monolithic, and in the presence of stone - rubble concrete. For the manufacture of columnar foundations, brick, reinforced concrete, metal and asbestos-cement pillars and pipes are used, and for pile foundations, ready-made reinforced concrete piles or driven and bored piles are used, made by filling a well worked out (drilled) in the ground with a concrete mixture.
Foundation types
Strip foundations most often performed under the walls of buildings (A), sometimes to give greater rigidity and ensure alignment of the settlement, structures are used under columns in the form of single (B) or cross (C) tapes. Reducing the pressure along the base of foundations of this type can be achieved only by increasing the dimensions in the transverse direction.
Separate foundations usually arranged under the columns of frame buildings (A), sometimes they are also used under the walls of frameless structures (columnar foundations) (B), if reliable soils lie at the base and the load on the foundations is not large. Separate foundations for columns are used in cases where uneven settlements do not exceed the maximum allowable values, since such foundations do not significantly affect the rigidity of buildings and are not able to equalize settlements. You can change the pressure at the base of these foundations by varying the length and width of the sole.
solid foundations perform, as a rule, under the entire building or structure in the form of solid reinforced concrete slabs. They can be placed under walls or columns (A). In some cases, to create greater rigidity, a solid foundation is erected in a slab-and-beam version (B). There are other constructive solutions for solid foundations; they can be box-shaped (C), as well as in the form of cylindrical shells (G) or shells of double curvature (D).
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Solid foundations, working on bending, even out settlements in two mutually perpendicular directions, ensuring joint operation of the foundation and the entire building. Box-shaped foundations, which are used in buildings that transfer unevenly distributed loads of considerable intensity to the base, have the greatest rigidity.
massive foundations perform in the form of a continuous rigid array for the entire structure. Foundations of this type are used in the construction of chimneys, blast furnaces, bridge supports, mast structures, the distinguishing feature of which is relatively small dimensions in comparison with the structure, with significant vertical and horizontal loads transferred to the base.
Foundations
The foundations of buildings and structures are designed taking into account the joint work of the structure and foundation soils, and the design of the foundation is largely determined by the type of building being erected. Widespread in the conditions of mass urban development received prefabricated foundations, allowing to reduce the cost of their construction.
Under the walls of frameless buildings, it is most advisable to use strip foundations, during the construction of which a layer of sand preparation 6-10 cm thick is poured onto the bottom of the pit, which is further leveled with the subsequent laying of standard pillow blocks on it, distributing the load from the walls of the building to the base. Standard wall foundation blocks are installed on pillow blocks in several rows.
Cushion blocks of strip foundations can be solid (A, B), ribbed (C) and hollow (D). Solid slabs are used for significant loads, while ribbed and hollow slabs are used for small ones, and the use of the latter allows saving building materials. Foundation walls are assembled from solid or hollow wall foundation blocks.
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The installation of foundation blocks in the plan is carried out relative to the alignment axes in two mutually perpendicular directions, combining the axial risks of the foundations with landmarks fixed on the base, or controlling the correct installation with geodetic instruments. Work begins with the installation of lighthouse blocks in the corners of the building and at the intersections of the axes, and the installation of ordinary blocks is started only after the position of the lighthouse blocks in plan and in height has been adjusted. Installation of blocks on the bases covered with water or snow is not allowed.
The position in the plan is controlled by measuring the lengths of the sides of the foundation, and to determine the rectangularity - by measuring the distances along the diagonal. Altitude position is determined by a level or water level.
Ordinary blocks are installed, orienting the bottom along the edge of the blocks of the lower row, the top - along the center axis. Blocks of external walls installed below the ground level must be aligned on the inside of the wall, higher - on the outside. Prefabricated elements are mounted on a prepared bed of cement mortar. Excess mortar must be removed before it sets to avoid difficulties in vertical waterproofing of basement walls.
During the installation process, the vertical joints between the blocks are filled with a mortar, first coating the joints with a thick cement mortar from the outside, and then clogging the joints with a mortar with a bayonet seal, using smooth reinforcing bars with a diameter of 16-22 mm.
When building a foundation with a basement on dry, non-rocky soils, concrete blocks of the FBS brand can be laid directly on a sand-leveled soil base. This design option without the use of strip foundation elements of the FL brand is also used when constructing a shallow foundation.
Intermittent strip foundations suit in cases where the estimated width of the foundation does not match the width of standard blocks. The use of discontinuous foundations is allowed with reliable soils and relatively small loads.
The sequence of installation of intermittent prefabricated foundation elements, starting with the installation of lighthouse blocks in the corners of the building, is the same as in the previous version. The gaps between the blocks are filled with sand, followed by compaction.
Prefabricated-monolithic discontinuous foundations are made from the same prefabricated elements as in the construction of prefabricated discontinuous foundations, in the following technological sequence. First, beacon blocks-pillows FL are installed in the corners of the building. After reconciliation of their design position, ordinary pillow blocks are laid out with an interval, which is determined by calculation. The corner cushion blocks should be wider than the ordinary ones, because they will serve as a support for the blocks of two walls. Then, FBS wall blocks are installed on ordinary pillow blocks, the width of which can be 300, 400, 500 and 600 mm, depending on the gap between the pillow blocks. Next, you should fix the formwork panels between the rows of wall blocks, after which you can proceed to layer-by-layer filling with concrete of class B12.5 (M150), with compaction of each layer with a vibrator.
In order to provide openings in monolithic sections for entering communications into the house, it is necessary to install nozzles in the formwork or a box of the appropriate size made of boards before concreting
On device tape prefabricated-monolithic foundation the floor of the basement is a monolithic reinforced concrete slab, on which the walls rest. Competently executed horizontal waterproofing of the basement floor with the transition to vertical waterproofing of the walls ensures the watertightness of the entire structure in the presence of groundwater backwater.
The sequence of work is as follows. Having leveled the base with a layer of sand or gravel up to 10 cm thick, a formwork of boards is installed along the contour of the concrete preparation. Then the base soil and the formwork are moistened with water and the formwork is filled with concrete mix Ml50 (concrete class B10) to the set mark at a height of 10-15 cm.
Depending on the loads on the foundation, the concrete base in the places where the wall blocks are supported is reinforced, for example, with a reinforcing mesh with cells of 10 x 10 cm from ASh class reinforcement with a diameter of 10 mm, a width of 1 m. The width and thickness of the reinforced monolithic tape are determined by calculation.
After the concrete has gained 50% strength, the formwork is removed, and the surface is primed, dried and waterproofed with two layers of rolled material (roofing material, glass roofing material, isol, hydroisol, etc.), releasing it 30-50 cm beyond the concrete base with so that after the installation of the FBS wall blocks, the waterproofing carpet can be glued on the outside and docked with the outer vertical waterproofing of the basement walls. Next, the waterproofing is covered with a layer of concrete or mortar, the surface of which is the basement floor.
To protect against mechanical damage, the outer waterproofing must be protected and clamped with a protective structure made of concrete, brick or smooth asbestos-cement sheets. The latter are leaned against the waterproofing and the sinus is covered with soil with layer-by-layer tamping.
When the groundwater level is at least 0.5 m below the base of the foundation, the pasting waterproofing can be replaced with a layered paint waterproofing with a total thickness of 3-5 mm.
Reinforced concrete monolithic foundations are designed as flexible structures on a compressible base, taking into account the joint work of the structure with the soil. The sections and reinforcement of such foundations are assigned taking into account the design rules for reinforced concrete structures.
The device of the upper part of the foundation depends on the type of supporting structures and the nature of the transmitted forces. Under the columns of frame buildings in the foundations, glasses are arranged (A) or a joint is provided using embedded parts (B), for which special reinforcement is installed in a monolithic foundation.
When using reinforced concrete columns of the frame, the glass part of the foundation is placed at a mark of - 0.150 from the surface of the earth in order to fill the sinuses before the installation of the columns, with metal columns, the edge of the foundation is placed much lower so that the metal column is located below the planning mark.
Monolithic reinforced concrete structures, depending on the acting forces, soil conditions and the dimensions of the structures based on them, can be one-, two- and three-stage.
Under the sole of monolithic foundations, a preparation is made of lean concrete or a layer of crushed stone rammed into the ground, poured with cement mortar, which ensures that the cement milk does not flow into the ground (if there are filtering soils in the base), the interaction of the concrete mixture with the soil, as well as the possibility of immersing the reinforcement in priming. If there are dense soils in the base, the filtration capacity of which is low, the preparation is not satisfied, taking in this case the thickness of the concrete protective layer of 5-8 cm.
Columnar shallow foundations can be made of brick (A) and cast concrete (B). First, wet sand is poured into the open pit with layer-by-layer compaction with a layer 50-60 cm thick, then roofing felt or roofing material is spread so that the cement milk from the concrete (mortar) does not seep into the sand, after which they start laying bricks on the M50 cement mortar, and with a monolithic option - for laying concrete M200. The walls of the pillars should be narrowed upwards.
To reduce pressure on weak soils, columnar foundations made of piece materials are widened in the lower part, making ledges at least 2 rows of masonry high. The tangential forces of frost heaving are neutralized by broadening the base of the foundation in the form of an anchor platform, with the laying of a reinforcing cage.
After completing the installation of the pillars, it is necessary to check the marks of their upper edge (mounting horizon) and, if necessary, level the tops with a 1: 2 cement mortar
In order to increase the stability of the columnar foundations and prevent their horizontal displacement and overturning, as well as to arrange the supporting part of the base between the pillars, they arrange a “stitching”. If the building is wooden, the function of the grillage can be performed by a wooden strapping made of logs or timber. In this case, the space between the blind area and the strapping is filled with a pick-up.
When erecting stone and brick walls, a reinforced concrete grillage laid on top of the pillars can serve as the supporting part of the basement. The grillage is also made in the form of an ordinary jumper, reinforced with 4-6 reinforcing bars with a diameter of 10-12 mm, laid on a concrete layer 70 mm thick. The height of an ordinary jumper should be 1/4 of the span, but not less than 4 rows of masonry. The grillage can be made in the form of a monolithic or prefabricated reinforced concrete rand beam.
Pillar foundations from ready-made standard concrete blocks are a structure consisting of a set of individual blocks laid on a cement mortar. The number of blocks depends on the depth of the foundation. Pits are dug under the foundation pillars with slopes of the required depth, and the dimensions in the plan depend on the width and length of the prefabricated elements used, plus at least 20 cm on each side for the installation of a sand cushion.
In order to increase the stability of the foundation pillars and create a support for the construction of walls, after aligning the marks of the upper edge of the pillars, a grillage is made of precast concrete elements or monolithic reinforced concrete. If the loads on the lintels exceed their calculated bearing capacity, especially during construction on subsidence and bulk soils, then a monolithic reinforced concrete strapping belt is additionally arranged along the top of the lintels.
Prior to the beginning of the installation of the latter, the prefabricated jumpers are securely connected to each other, for which the mounting loops are connected with a wire twist crosswise or welded pieces of reinforcement with a diameter of 8-10 mm. After that, formwork is arranged on top of the lintels, a layer of M100 cement mortar 4-5 cm thick is spread, a reinforcing cage is installed and the M200 concrete mixture is laid. The surface of the concrete is leveled and covered with any rolled material to protect it from atmospheric influences. After gaining strength and waterproofing, you can proceed with the installation of floor slabs.
pile foundation consider a group of piles united from above by a special design in the form of slabs or beams - grillages, which are designed to transfer and evenly distribute the load on the piles. Grills, being load-bearing structures, serve to support the above-ground structures of buildings.
There are pile foundations with a low grillage, intermediate and high.
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A low grillage (A) is located below the planned surface of the earth. Being a part of the pile foundation and interacting with the foundation soil, it is able to transfer part of the vertical pressure to the foundation along its sole and absorb horizontal forces. When installing a grillage in the freezing zone, normal and tangential frost heaving forces will act on it, therefore, it is recommended to place low grillages in heaving-dangerous soils below the freezing zone or use measures aimed at reducing the harmful effects as a result of freezing.
In a pile foundation with a low grillage, the grillage itself, piles and the soil located in the inter-pile space participate in joint work, and the piles work mainly in compression.
An intermediate grillage (B) is arranged directly on the soil surface without deepening and is used when constructing pile foundations on non-porous soils. Due to the fact that the upper layers of the soil, as a rule, have a low bearing capacity, intermediate grillages cannot transmit vertical pressure along their sole.
High grillages (B) are located at some distance from the surface of the earth. A pile foundation with such a grillage is used under the internal walls of civil and residential buildings with technical undergrounds, bridge supports, etc.
To increase rigidity under the action of horizontal loads (except for vertical ones), inclined piles are also driven. Such structures are calculated as flat or spatial frames, in which the grillage is considered to be a rigid or flexible crossbar, and piles are considered vertical or inclined posts working in bending, eccentric compression or tension.
In the practice of urban construction, the following types of pile foundations are used: from single piles, strip pile foundations, pile bushes and continuous pile fields.
Foundations from single piles are used only for light, as a rule, frame buildings, when the load transmitted by the column can be taken by one pile. In some cases, so-called pile-columns are used, which, being both piles and columns of the building, lead to a significant reduction in the complexity of construction and installation work.
Strip foundations are used mainly for load-bearing walls and other extended structures. Piles in the foundation are arranged in 1, 2 or more rows in a linear or checkerboard pattern. With a multi-row arrangement of piles, the strip foundation, having greater rigidity, is able to perceive an eccentrically applied load without bending the piles, while with a single-row arrangement, the piles will work in bending.
Pile bushes are used mainly for individual supports (columns and poles). The minimum number of piles in such a foundation must be at least 3. A pile cluster of 2 piles can also be used, but only if, with the help of design and construction measures, it is possible to prevent the development of pile bending in a plane perpendicular to the axis passing through both piles.
Solid pile fields are used for heavy multi-storey and tower structures with small dimensions in plan. A pile field is also often called a system of piles placed on a construction site under a structure under construction. Fields can consist of single piles, bushes or a system of piles for strip foundations.
Slab foundations from cross reinforced concrete beams (tapes) are erected from monolithic reinforced concrete in order to give the foundation spatial rigidity. The need for this arises during construction on uneven and highly compressible soils, for example, on bulk soils (sand cushions, compacted landfills, heavily heaving soils, etc.). Sometimes the term "floating" is applied to such shallow foundations.
The slab foundation is quite material-intensive, so it is advisable to arrange it when building small and compact houses or other buildings without a high base, when the slab itself is used as a floor (for example, garages, bathhouses, etc.). For houses of a higher class, foundations are more often arranged in the form of ribbed slabs or reinforced cross tapes.
To protect shallow foundations from freezing, they must be insulated, arranging thermal insulation around the perimeter of the foundation.
Recessed solid slab foundations in the form of a monolithic slab under the entire building provide the most even distribution of the load on the foundation and, as a result, uniform settlement of the building. In addition, they well protect basements from backwater groundwater.
Method "wall in the ground" designed for the construction of structures buried in the ground for various purposes: tunnels, garages, parking lots, industrial underground storage facilities, hydraulic structures, building foundations. A "wall in the ground" is usually understood not only as a construction of a deep foundation, but also as a certain technology for constructing underground facilities. A deep narrow trench is dug along the contour of the future structure (usually 0.6 m wide, 20-30 m deep, in some cases up to 50 m), reinforcement is installed in it and filled with a concrete mixture (sometimes precast concrete elements are used). After that, the soil inside the contour of the formed closed wall is removed with the help of earthmoving machines and an underground space is created.
To facilitate the perception of the lateral pressure of the soil by reinforced concrete walls, spacers or anchor fastenings are arranged at one or several levels (by drilling holes in the wall and in the ground and arranging reinforced concrete rods in them). Spacer fastenings are used if the distance between parallel walls is less than 15 m. Anchor fastenings are preferable, and injection type in one or, if necessary, in two levels.
To prevent the walls of deep trenches from collapsing, during excavation, such trenches are filled with a clay solution (bentonite suspension), which creates excess hydrostatic pressure on the vertical walls of the trench, so that they remain even.
This technology is most in demand in the conditions of reconstruction of historical city centers with dense buildings, close to existing buildings, since open pits are not used for its application, which means that the construction site area is saved, it is safe for nearby buildings and structures. In addition, this method of forming load-bearing walls saves up to 25% of the estimated cost. For retaining walls and fences, the savings are even higher - up to 50%, and for anti-filtration curtains - up to 65%. Additional savings are achieved as a result of the abandonment of expensive work on dewatering, dewatering, freezing and cementing of soils. Among its advantages are also the speed of work, lower energy consumption of construction, the ability to save scarce materials.
During the construction of the “wall in the ground”, the following main technological processes are performed:
Device foreshahty - directing trenches;
Development in horizontal layers from top to bottom under a clay bentonite suspension of short trenches with separate grips through one with a double-jaw type grab or a multi-bucket cutter-type excavator;
Reinforcement and concreting of the trench in separate sections.
Formwork of stepped glass-type foundations for columns:
a - from shields on stitched slats: 1 - embedded shield, 2 - overhead shield, 3 - formwork-hollow former, 4 - support beam, 5 - heavy (twisting); b- from inventory boards: 1-corner formwork boards, 2- scrums, 3- upper stage formwork, 4- glass former, 5- flags ..
Plank formwork for stepped glass-type foundations assembled from pairs of shields - mortgages and covers (rice a ). In each tier, the embedded shields are inserted between the covering ones, and the box thus obtained is pulled together with strands or twisting, which perceive the lateral pressure of the concrete mix. The glass is formed using a special formwork - a void former (it has the shape of a truncated pyramid), which is installed on the upper box with the help of support bars.
Installation of inventory formwork (see fig. b) start with the installation of mounting angles and corner shields. The shields are attached to the lower bouts with tension clamps, and between themselves - with brackets. Then, the contractions of the second tier are hung on the formwork panels of the column. With a column height of more than 1800 mm, the formwork is made up of two or more tiers of panels. A glass former is installed and fixed on the upper box. Flags are used to fasten fights. The contractions are bolted to the corner elements of the shields.
Technological methods for laying the concrete mixture are prescribed depending on the types of structures and requirements for them, the composition of the concrete mixture used, the design features of the formwork, and the methods of supplying the mixture to the places of laying. Taking into account these factors, practice has developed effective methods for laying concrete mix, which are described below for various types of the most massive
structures.
IN foundations and arrays depending on the volume, depth, height and other features, the concrete mixture is laid according to the following technological schemes: with the unloading of the mixture from the transport device directly into the formwork from a mobile bridge or overpass, using vibratory feeders and vibration chutes, concrete pavers, concrete pumps, buckets using cranes.
When laying in low-reinforced foundations and arrays, rigid concrete mixes with a cone draft of 1 ... 3 cm are used, in densely reinforced ones with a cone draft of 4 ... 6 cm.
The scheme of laying the concrete mixture in stepped foundations:
/ - foundation formwork; 2 - tub with concrete mix; 3 -working flooring with a fence; 4 - vibrator; 5 - link trunk
In stepped foundations with a total height of up to 3 m and an area of the lower step up to 6 m 2, the mixture is fed through the upper edge of the formwork (Fig.a), providing measures against displacement of anchor bolts and embedded parts. During vibrocompaction, internal vibrators are immersed in the mixture through the open edges of the lower step and rearranged along the perimeter of the step towards the center of the foundation. Vibrocompaction of concrete of the second and third stages is carried out similarly, after which they are smoothed. Concrete mixture can be laid into pylons immediately after the completion of laying in steps. The mixture is fed into the pylon through the top of the formwork. They seal it with internal vibrators, lowering them from above.
With a height of stepped foundations of more than 3 m and an area of the lower step of more than 6 m 2, the first portions of the concrete mixture enter the lower step along the perimeter (Fig. b). Subsequently, the mixture is fed through the receiving hopper and link trunks (Fig. in). Vibrocompaction of the mixture is carried out, as in the previous case, by internal vibrators.
In high pylons, a concrete mixture with a mobility of 4 ... 6 cm must be fed slowly and even with some interruptions (1 ... 1.5 hours) in order to prevent the concrete laid in the steps from being squeezed out through their upper open faces.
In massive foundations that perceive dynamic loads (for example, under rolling, forging and pressing equipment), the concrete mixture is laid continuously. Their volume reaches 2.5 ... 3.0 thousand m 3. The concrete mix is fed into them from overpasses, conveyors, concrete pumps or combined methods at a rate of up to 300...350 m 3 per shift. The mixture is fed into hard-to-reach places of the array and distributed over the area of the foundation with the help of vibration chutes.
The concrete mixture is placed in massive foundations with thick reinforcement in horizontal layers 0.3 ... 0.4 m thick, compacting it with manual internal vibrators.
According to the method of construction, the foundations are divided into monolithic and prefabricated.
Under the columns of a frame building, as a rule, columnar foundations with glass-type undercolumns are arranged, and the walls rest on foundation beams. Strip and solid foundations are rarely provided, as a rule, on weak, subsiding soils and at high shock loads on the soil of technological equipment.
Unified monolithic reinforced concrete foundations have a stepped shape with a glass-type undercolumn for embedding columns (Fig. 2).
under-column section
Fig.2. General view of a monolithic stepped foundation with a glass-type column under the outermost column
Prefabricated foundations are more economical than monolithic ones, but they consume more steel. Lighter and more economical in terms of steel consumption are prefabricated foundations of a ribbed or hollow structure.
With a close location of the groundwater level (GWL) and with weak soils, pile foundations are arranged. The most common are reinforced concrete piles of round and square sections. At the top of the piles, they are connected with a monolithic or prefabricated reinforced concrete grillage, which also serves as a sub-column.
The column is installed on the slab over a layer of cement-sand mortar. Under the action of a bending moment on the foundation, the connection of the under-column with the slab is reinforced by welding of embedded elements, and the welding points are sealed with concrete.
The steps of the slab of all foundations have a single unified height of 300 mm or 450 mm.
In the upper part of the column there is a glass for installing a column in it. The bottom of the glass is placed 50 mm below the design mark of the bottom of the column in order to compensate for inaccuracies in size and foundation with a grout.
Columns with the foundation are connected in various ways. Mostly with concrete. To ensure the rigid fixing of the column in the foundation glass, horizontal grooves are arranged on the side surfaces of the reinforced concrete column. The gap between the faces of the column and the walls of the glass on top is 75 mm, and at the bottom of the glass 50 mm (Fig. 2).
The edge of the foundation for reinforced concrete columns is located at the level of -0.15 m, for steel columns - at the levels of -0.7 m or -1.0 m.
Foundations for adjacent columns in expansion joints are made common, regardless of the number of columns in the node. In this case, a separate glass is arranged for each precast concrete column (Fig. 3).
Rice. 3. Monolithic reinforced concrete foundations
columns in places where expansion joints are installed
In the foundations for steel columns, the column is made solid (without a glass) with anchor bolts (Fig. 4).
Rice. 4. Monolithic foundations for steel columns:
a) columns of constant section;
b) two-branch columns (through section)
The walls of frame buildings rest on foundation beams, laid between the under-columns of the foundations on concrete columns of the required height, concreted on the ledges of the foundations (Fig. 2). Foundation beams have a tee or trapezoidal cross section (Fig. 5). Their nominal length is 6 and 12 m. The structural length of the foundation beams is selected depending on the width of the under-column and the location of the beams. The upper edge of the beams is located 30 mm below the level of the finished floor.
Rice. 5. Sections of foundation beams:
a) for a column spacing of 6 m;
b) for a column spacing of 12 m
Foundation beams are installed on a grout of cement-sand mortar 20 mm thick. This solution fills the gaps between the ends of the beams and the walls of the pillars. 1-2 layers of rolled waterproof material on mastic are laid along the beams for waterproofing the walls. In order to avoid deformation of the beams due to heaving of soils from below and from the sides of the beams, a backfill of slag, sand or brick rubble is provided (Fig. 6).
Rice. 6. Detail of the basement of a one-story industrial building
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Foundations of industrial buildings
Foundations of industrial buildings
Foundations of prefabricated reinforced concrete columns. Under prefabricated reinforced concrete columns, reinforced concrete prefabricated or monolithic foundations of the glass type are used.
Prefabricated foundations can consist of one reinforced concrete block (shoe) of glass type or from a reinforced concrete block-glass and one or more base plates under it (Fig.
Monolithic reinforced concrete foundations have a symmetrical stepped shape with two or three rectangular steps and a sub-column in which a glass for the column is placed (Fig. 27). The bottom of the glass is located 50 mm below the design mark of the bottom of the column, so that after stripping the foundation by pouring a layer of cement mortar (or concrete) to compensate for possible inaccuracies in the dimensions and laying of the foundations.
foundations are usually designed with a mark of the top of the column at the level of the planning mark of the ground - 0.150.
The foundations can have a total height of 12004-3000 mm with a gradation of 300 mm, which corresponds to the greatest depth of the foundation footing - 3.150.
In this case, the height of the foundation changes due to the height of the under-column at; constant step height.
Rice. 26. Constructive solutions for prefabricated foundations of industrial buildings: a - single-block; b - two-block; in - multiblock; 1 - glass; 2 - plate
27. Monolithic reinforced concrete foundation: 1 - patella; 2 - steps
If it is necessary to lay foundations deeper, they make a pillow of sand or concrete under them (see; Fig. 27).
In buildings with basements, the foundations are located below the basement floor by increasing the height of the patella.
The foundations are made of concrete grades 150 and 200. The foundations are reinforced with a welded mesh with cells of 200 × 200 mm, located at the base of the foundation with a protective layer of 35-70 mm.
For working reinforcement, hot-rolled steel of a periodic profile of class A-P is used. The armrests are reinforced in the same way as the corresponding columns. In the presence of weak soils under the foundations, a preparation with a thickness of 100 mm from "concrete" is arranged. Binding of foundations to the alignment axes is determined by the binding of the column.
Foundations of steel columns. Under steel columns, as a rule, reinforced concrete monolithic foundations are arranged.
The under-columns are made solid (without glasses) and provided with anchor bolts to secure the column shoe.
The top of the sub-column is positioned so that the steel column shoe and the upper ends of the anchor bolts are covered with the floor. For this purpose, depending on the type of shoe, the mark of the top of the foundation is assigned - 0.4-1 m.
If it is necessary to deepen the foundations of steel columns by 4 m or more, it is possible to use prefabricated reinforced concrete under-columns, manufactured according to the type of prefabricated reinforced concrete two-branch columns.
Such a sub-column is fixed with its lower end in the foundation glass, at the upper end it has anchor bolts for attaching a steel column. The foundation for adjacent columns is arranged in common even if the number of adjacent columns includes both steel and reinforced concrete columns.
Steel columns are installed on foundations, in which anchor bolts are pre-embedded to fasten the columns.
The design position of the columns in the plan is ensured by the correct location of the anchor bolts on the foundations, and the accuracy of the installation in height is ensured by the careful preparation of the supporting columns: the surfaces of the foundations.
Rice. 29. Foundations for steel columns with supporting steel parts: a - view of the shoe and support; b - conductor; 1 - support beams; 2 - embedded parts; 3 - risks of axes; 4 - conductor with holes for anchor bolts; 5 and 6 - risks of axes on the shoe of the column; 7 - gravy
Columns are supported in one of the following ways:
1) on the surface of the foundation, erected to the design mark of the base of the column, without subsequent grouting with cement mortar.
the ot0m method is used for columns with milled shoe soles (Fig. 28);
2) on pre-installed and calibrated support parts (beams, rails, etc.) followed by grouting with cement mortar (Fig.
29). the foundation is concreted to a level of 250-300 mm below the design mark of the supporting plane of the column shoe. Then the supporting parts and embedded parts are installed, the upper part of the foundation is concreted to a level of 40-50 mm below the top of the supporting parts. The supporting (lower) surface of the column shoe with this method of preparing the foundation must be made strictly perpendicular to the axis of the column;
30. Foundation for a steel column with a base plate: 1 - base plate; 2 - strips with threaded holes; 3 - set screws; 4 - conductor with holes for anchor bolts; 5 - risks of center axes; 6 - anchor bolts; 7 - embedded parts; 8 - gravy; 9 - top of the foundation; 10 - bottom of the column shoe
3) on pre-installed, calibrated and poured with cement mortar steel base plates (Fig.
thirty). The foundation is concreted to a level of 50-80 mm below the design mark of the slab sole, then the base plates are installed, combining their axial risks with the risks of the center axes on the parts embedded in the foundation. The position of each plate in height is adjusted by set screws so that the upper plane of the plate is located on
the design elevation of the reference plane of the column shoe.
The bearing surfaces of slabs and columns must be planed at the factory.
Foundations for walls. Strip, columnar or pile foundations are arranged under the walls of buildings and structures.
Strip foundations, as a rule, are arranged under load-bearing or self-supporting brick and block walls.
They can be prefabricated or monolithic. The most common prefabricated strip foundations. These foundations are made of reinforced concrete and concrete blocks or enlarged elements. Block foundations are the most widely used. Tape Foundations are made of blocks of two types: wall rectangular blocks (SP grade) and block pillows (F grade). Wall blocks (Fig. 31, a) have a single nominal height of 600 mm, a single nominal; nal length 2400 mm and thickness - from 300 to 600 mm.
In addition to the main wall blocks of the SP brand, there are additional blocks of the SPD brand | nominal length 800 mm, which are used for ligation of blocks in the foundation.
Wall blocks are made without reinforcement - solid and with non-through voids, open downwards.
Solid blocks have an additional letter "C" in the designation.
Block pillows (Fig. 31, b) are used to increase the width of the base of the foundation and, accordingly, are reinforced along the bottom with welded meshes.
31. Wall foundations: a - wall block; b - block pillow
Rice. 32. Strip foundations from wall blocks and block pillows
Block pillows have a nominal length of 1200-2400, a width of 1000-2400 and a thickness of 300 and 400 mm.
Blocks with a width of 1000 h-1600 mm, in addition to the main dimensions, are made additional - half the length.
Wall blocks are made of concrete of grade 150, block pillows are made of concrete of grades 150-200.
For the main working reinforcement of block pillows, hot-rolled steel of class A-P is used.
On fig. 32 shows diagrams of strip foundations from wall blocks and block pillows.
Block pillows are laid on a leveled base or on sandy preparation. Block foundations can be solid or discontinuous. In discontinuous foundations, pillows are laid with a gap of 0.2-0.9 m. This design reduces material consumption, reduces labor costs and allows better use of the bearing capacity of soils.
When erecting buildings or structures on highly compressible or subsidence soils, a reinforced seam 3-5 cm thick is arranged along the foundation cushions, and a reinforced belt 10-15 cm thick is placed over the foundation.
This increases the rigidity of the foundation and prevents the appearance of cracks in case of uneven settlement of the building.
Wall blocks are laid on cement mortar over foundation pads. Basement walls are built from such blocks. At the same time, the foundations and walls of the basement consist of several rows of wall blocks laid with bandaging of the seams.
Longitudinal and transverse 1 walls of such foundations are interconnected by ligation of blocks.
Foundations made of large-sized reinforced concrete elements are arranged from pillow panels and wall panels (Fig. 33). Cushion panels (ribbed or solid) are laid in the form of a continuous or intermittent tape under the walls of large panels.
On top of them, panel-walls are installed (solid, ribbed or with through voids). Installed panels are interconnected by electric welding of embedded steel parts in them.
Rice. 33. Strip foundations made of large-sized reinforced concrete under the walls
34. Pillar foundations
Monolithic strip foundations are made of concrete or reinforced concrete. They are erected in the formwork, where reinforcement is installed (with reinforced concrete foundations) and concrete of the design grade is laid.
Columnar foundations (Fig. 34) are arranged for walls with solid foundations and small loads on them. Under the load-bearing walls, the foundation supports are located in the corners, at the junctions and intersections of the walls, as well as at intervals at a distance of no more than 3-6 m.
At the same time, free-standing supports are interconnected by reinforced concrete foundation beams that take the load from the walls. Under the foundation beams, to prevent deformations associated with heaving by planting the base, a slag or sand bed with a thickness of 0.5-0.6 m is arranged.
Pile foundations (Fig. 35) are arranged with weak soils lying to great depths.
Depending on the various features, piles are divided into different types. According to the material, the piles are reinforced concrete, concrete, steel and wood. Reinforced concrete piles, in turn, are divided into prefabricated and monolithic. The most common prefabricated piles.
They are made of two types: solid - square in plan and tubular - cylindrical. Concrete piles, as a rule, are made monolithic, with different diameters and depths. Steel piles are made of I-beams, channels, pipes. Due to the scarcity of metal and instability to corrosion, steel piles are rarely used. Wooden piles are made from coniferous forests. To protect against soaking during driving, a steel ring (yoke) is put on the upper end of the piles, and a steel shoe is put on the lower end.
According to the method of manufacture and immersion in the ground, piles are divided into driven and stuffed.
Driven piles are made of prefabricated reinforced concrete, steel or wood. They are immersed (driven) into the ground with special mechanisms by driving, pressing, vibration, screwing (steel screw piles).
35. Pile foundations: a _ on pile-racks; b - on hanging piles; c - types of driven piles; g - pile grillages; 1 - piles; 2 - grillage; 3 - yoke; 4 - steel shoe; 5 - steel flange welded to the pile reinforcement; 6 - steel tip; 7 - hole; 8 - reinforced concrete prefabricated pile head; 9 - prefabricated reinforced concrete grillage, welded to the head; 10 - releases of reinforcement from piles; 11 - concrete
Stuffed piles are monolithic (Fig.
36). They are arranged directly in the ground from concrete or reinforced concrete with the help of special casing pipes immersed in wells previously arranged in the ground. Stuffed reinforced concrete piles are used for heavy loads on foundations, they have a diameter of 1000 mm, respectively, and a depth of 30 m or more.
According to the nature of work in the ground, piles are divided into hanging and rack piles.
The pile posts pass through soft soil and rest on solid (rocky) soil with their lower ends, transferring the entire load from the building to it.
Hanging piles do not reach solid soil, but only compact weak soil. Hanging piles perceive the load from the building mainly due to the friction forces that arise between their side surface and the ground.
Compared with other types of foundations, piles have a number of advantages: they provide less precipitation, increase the level of industrialization, reduce the amount of excavation, reduce construction time and cost.
Currently, in industrial, civil and transport construction, of the corresponding designs of stuffed piles, bored piles are most widely used (5-10% of the total number of piles used), especially in areas where subsidence and bulk soils occur. Such piles are usually made with a diameter of 500-800 mm with a broadened base with a diameter of 1200-2000 mm.
36. Stuffed piles: a - made in a removable casing pipe; b - often rammed with a metal shoe; in - with a radial broadened heel; g - camouflage; e - deep laying of the "B.enoto" system; 1 - metal shoe; 2 - monolithic grillage; 3 - pile F 1.2 m; 4 - dense soil rocks
Stuffed piles are made by special machines with inventory casing pipes, which are subsequently removed or left in the ground.
Well drilling for the installation of bored piles is carried out with special installations URB-ZAM, UGBH-150 and special machines NBO-1, SP-45, including rotary drilling machines SO-2, SO-1200, etc.
Bored piles are also widely used abroad. In France and Japan they are made with special machines. In England, drilling for stuffed piles is carried out with attachments - augers and rotary drills mounted on cranes.
37. Protection of basements from ground dampness and ground water: a - ground water below the basement floor; b - the same, above the basement floor; c - rollless waterproofing of basements; 1 - coating with hot bitumen; 2-horizontal waterproofing (at the level of the basement floor); 3 - asphalt or concrete floor; 4 - top layer of horizontal waterproofing; 5 - groundwater level; 6 - protective brick wall; 7 - gluing waterproofing carpet; 8 - loading layer of concrete; extinguishing pressure of groundwater; 9 - sedimentary compensator; 10 - clay castle; 11 - waterproof plaster with the addition of ferric chloride; 12 - elastom (cold poly-merbitum coating); 13 - horizontal elastomer insulation
Details of devices from foundations.
When erecting foundations, especially under the walls of buildings I with basements, a number of other details are required: waterproofing, blind areas, pits, sedimentary joints.
Waterproofing. The foundations under the walls are exposed to atmospheric moisture seeping through the soil, as well as groundwater. Due to the capillarity, moisture rises up the foundation and causes dampening of the walls of the building. To block the access of moisture to the walls, arrange horizontal and vertical waterproofing.
On buildings without a basement, horizontal waterproofing is arranged on the same level with preparation for the floors of the first floor, and when installing floors along beams - 50-150 mm below the line.
Horizontal waterproofing is performed from 2 layers of roofing material to bituminous mastic or a layer of cement!
solution composition 1:2 with sealing additives (ceresite, sodium aluminate! ferric chloride) with a thickness of 20-30 mm.
Vertical waterproofing is used in buildings with basements, depending on the level of groundwater.
If the groundwater level is below the basement floor, then for insulation, the outer surface of the basement wall, which is in contact with the ground, is covered with two layers of hot bitumen.
At the same time, the floor of the subvzlz is water-tight (sphalt, cement) and prevents the access of ground dampness from below from the inside of the wall (Fig.
37a). If the groundwater level is higher than the basement floor, then in addition to the vertical waterproofing of the walls, waterproofing of the basement floor is arranged (Fig. 37, b, c). In this case, waterproofing is a continuous carpet of several layers (2-5) of waterproofing, isol, fiberglass and other rot-resistant rolled materials glued to the base (and EACH OTHER) with appropriate mastics. A waterproofing carpet is placed in the thickness of the floor on concrete preparation, passed through the foundation (basement walls) and brought to the surface of the outer walls 0.5 m above the possible (highest) groundwater level.
A layer of concrete is laid on the waterproofing carpet of the floor or a reinforced concrete slab (pressure plate) is laid on which a clean floor is laid. The waterproofing layer, located on the outer side of the wall, is protected from possible damage by facing of well-fired clay bricks on cement mortar. Above the cladding, the outer surface of the foundation (the walls are covered with hot bitumen.
Blind area.
In order to protect the base of the foundations from moisture by surface water, a waterproof blind area 0.5-1.5 m wide with a slope of 2-3% from the building is arranged around the entire perimeter from the outside of the building (Fig. 38). It is usually made from a layer of asphalt 20-30 mm thick laid on crushed stone preparation 100-150 mm thick.
38. Blind area, loading and light pits: A - blind area; B - loading hatch; B - light pits; 1 - asphalt layer; 2 - Crushed stone preparation; 3-concrete or brick wall; 4 - bottom in the pit with a slope from the building; 5 - lattice
Pits. When building foundations in buildings with basements, pits are usually arranged (see.
rice. 38). The pits, arranged near the walls of the basement, are used for lighting and loading fuel (for example, in boiler houses). The walls of the pits are made of prefabricated or monolithic reinforced concrete and bricks. The bottoms of the pits are made of concrete with slopes to the outlets for water drainage and are covered with steel gratings or lids from above.
Sedimentary seams. In cases where individual parts of the same building have different number of storeys, loads, construction dates or soil of different quality under them, uneven settlement of the building may occur, and, consequently, cracks appear that can lead to the destruction of the entire building.
Therefore, the foundation of the building, together with the wall located on it, is cut with a vertical sedimentary seam, which in continuous foundations is made in the form of a transverse vertical slot (Fig. 39). Vertically placed boards wrapped with roofing felt 13 mm thick are laid in the seam.
Types of foundations: tape, glass, pile, slab. What type of foundation to choose for the house?
At the end of the laying of the basement walls, the boards closest to the surface of the walls are removed, and the seams in these places are filled with waterproof material, bitumen, asphalt, etc.
Rice. 39. Sedimentary seam: 1 - foundation; 2 - seam; 3 - boards wrapped with roofing paper
Special cases of foundation construction.
When changing the depth of the foundation along the length of the walls, they gradually pass from one level to another - by means of ledges. The ratio of the height of the ledge to its length is taken to be no more than 1:2, and the height should be no more than 0.5 m, and the length - at least 1 m.
In seismic areas, taking into account the stability of foundations against overturning, it is recommended to design them in the form of systems of cross tapes and solid foundation slabs, avoiding the use of separate columnar foundations.
In areas of permafrost soils, foundations are often erected1 using the method of maintaining the frozen state of foundation soils.
In the ETOR case, the foundations consist of separate pillars connected over a reinforced concrete beam (rand beam), and the underground is ventilated in winter, which guarantees the preservation of the frozen state of the foundation soils.
When building foundations on subsiding (loess-like) soils, the subsiding properties of the latter are eliminated by protecting it from soaking or by compacting it with heavy rammers, using ground piles and chemical fixing.
During construction on quicksand, pile or solid foundations are used, and the pit is fenced with sheet piling and drainage is organized.
Cellars and technical undergrounds.
Foundation! buildings, which are the walls of the basement floor, form the premises of cellars and technical undergrounds. Premises with a height of more than 2.0 used for household needs are called a basement, and rooms of a lower height, intended for placing engineering equipment and laying communications, are called a technical Underground. The walls of basements and technical undergrounds are made of the same materials as the foundations. They must be resistant to horizontal ground pressure, have sufficient thermal protection and waterproofing. To illuminate the premises in the outer walls of basements and technical subfields, they arrange windows overlooking the light pits.
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Houses with a large multi-storey frame-panel type are most often installed on a glass-type foundation under the columns. 
In other words, on a special columnar base.
And they have a huge difference from the monolithic foundations that are used for low-rise buildings.
It is not surprising that such a foundation is used only in industrial construction, because such a cathedral structure will be practically impossible in domestic conditions without special units.
Indeed, in fact, this is a factory glass structure, which is placed in the pit and reinforced columns are already mounted in it.
Advantages and device of a glass foundation
And they are also produced in the factory.
What is a glass?
In everyday life, builders call this element a “shoe”, because its shape is not simple. In fact, these are several square monoliths, which become thinner as they approach the surface.
The dimensions of the foundations for all objects are purely individual and their calculation is carried out by a special construction bureau.
But all of them should be focused on GOST 24476-80.
it states that the shoe can have a minimum value of the lower square of 120 cm, and a maximum value of 210 cm.
They install special columns made of reinforced concrete, in which the cross section is from 30 to 40 cm.
Here is another addition to the article in the video:
The glass-type foundation for columns has its advantages:
- Phenomenal load capacity;
- Almost complete inertness to moisture;
- Installation is carried out in the shortest possible time, subject to the use of special equipment.
How are they arranged?
Most often, such skeletons can be found in the construction of workshops for production, large outbuildings, underground parking lots.
But most often during the construction of multi-storey frame houses.
It is formed from two main elements: a plate, which is the direct core, and under-columns, the so-called glasses.
Important! Such a foundation can be used only if the soil is of a stable type, does not have a tendency to subsidence and heaving.
Distinctive characteristics
The calculation for the base is based on what will be the future load on the skeleton and the type of soil on which the structure will be erected. The main difference between this foundation and others is the presence in it of elements inherent only to it.
And they differ in the height of the pedestal, the number of plates and the method of joining the shoe and the column.
It is the last moment that is tied to the material from which the column is made.
So, also metal columns have a fastening different from reinforced concrete columns. Most often, reinforced concrete columns are planted on a shoe using a concrete solution marked 200 and 300.
What does GOST say about this?
The main requirements that are voiced in this document regarding the glass-type foundation for columns are as follows:
- The concrete mixture must be marked at least 200 and correspond to its characteristics;
- The water resistance of concrete should be marked as B2;
- The water resistance threshold of the entire structure should not exceed five percent;
- Finished products can be delivered to the construction site only after they have gained their strength;
- The creation of a reinforcing belt is a mandatory procedure, the rods must be covered with concrete 30 mm thick;
- If reinforcement sticks out in the structure after pouring, then this is a marriage that is prohibited to use;
- Cracks in the structure exceeding 0.1 mm require replacement of the defective structure with a new one;
- If the products have mounting loops, they must be cut off, but in no case should they be driven into the structure.
Such skeletons abroad
The method of fastening the shoe and column described above is mainly used in the post-Soviet space.
Overseas technology is a little different.
So, the Hungarians prefer to make such a connection with the help of reinforcement bars let into the concrete.
Americans use welding to connect the outlets of a metal rod or attach everything to anchor bolts.
A steel plate is laid between the bolts and the frame, which takes on the function of a gasket.
But the Japanese take a sand cushion as the basis for the column, which is fixed in a reinforced concrete holder, of the desired size.
Construction stages
If we are talking about a cathedral structure for metal columns, then fastening is carried out only with the help of anchor bolts. The bolts here are special, which were produced on the basis of GOST 24379.1-80.
They must fully comply with the calculated parameters.
Tolerance -/+ 0.02 cm.
During installation, on special control are the indicators of alignment of the axes of the glass and the center axis, the absence of deviations in the sand for leveling and supports.
Important! The skeleton must lie completely on the base of the sole with the entire area.
The installation technology has the following steps:
- Well preparation;
- Formation of a pillow from sand and gravel, its ramming;
- Installing the glass with a crane;
- Similar to the previous process, but already along the column.
Its fastening on the shoe.
They are mounted focusing only on the axes, which are outlined by stripes on the edges of the glass. They are put by the builders themselves before starting work with any coloring agent of an indelible type.
The center line must be marked using string, plumb bob or wire and nails. And it is the coincidence of the axis on the shoe and the pivot on the column that indicates the correct installation.
As you can see, the design is more than monumental.
This is not surprising, because, for example, an apartment building will stand on it, in which hundreds of families will live and their lives depend on how correctly the foundation was erected.
It often happens that the skeleton was erected purely according to the project, but already there was an error in it. The result in both cases is sad.
Therefore, those who are engaged in such serious and responsible activities should treat their work with maximum responsibility.
This connection is very convenient because the components of the piles (6-10 meters each) are automatically connected to each other during driving.
The joint itself is a metal "glass" or a piece of steel pipe, at one end of which there is a chamfer, and the other end is fixed to the reinforcing outlets of the lower end of the element and is securely welded.
glass type foundation
The welds are inside the connecting pipe. The outer surface of the glass must be covered with a zinc solution, which effectively prevents the development of corrosion and further destruction of the joint. For the convenience of joining the sections, their lower part has a cylindrical part.
The first link is hammered in half the length of the pile. This is done using cylindrical subbraces. Further, the second link (lower cylindrical part) is introduced into the tubular cup. A special annular protrusion of each next link is cut off with a “glass” to fit the inner diameter of the joint, due to which the resulting connection is very tight and reliable.
The high rigidity of the connection allows the pile elements to endure significant bearing loads.
This connection provides the minimum consumption of steel, in comparison with bolted or wedge-shaped connections.
Composite piles are made of heavy grade concrete. Special fillers and enriched sand make it possible to achieve high frost resistance and water resistance of concrete, so the finished elements can be used in aggressive environments.
To increase the impact resistance of reinforced concrete composite piles, they are reinforced with high-class steel wire.
TYPICAL TECHNOLOGICAL CHART (TTK)
PERFORMANCE OF WORKS ON INSTALLATION OF BLOCK TYPE FOUNDATION BLOCKS
1 AREA OF USE
1.1. A typical technological map (hereinafter referred to as TTK) has been developed for a set of works on the installation of glass-type foundation blocks for industrial buildings.
A typical flow chart is intended for use in the development of Work Production Projects (PPR), Construction Organization Projects (POS), other organizational and technological documentation, as well as to familiarize workers and engineering and technical workers with the rules for the production of installation work.
The purpose of creating the presented TTK is to show the technological sequence of construction processes and installation work, the composition and content of the TTK, examples of filling in the necessary tables and schedules, and assisting builders and designers in the development of technological documentation.
On the basis of the TTC, Working Flow Charts are developed, which are part of the Project for the execution of works, for the implementation of certain types of construction and installation and special construction processes, the products of which are finished structural elements of a building or structure, process equipment, as well as for the production of certain types of work.
When linking a Standard flow chart to a specific facility and construction conditions, production schemes, scopes of work, labor costs, mechanization tools, materials, equipment, etc. are specified.
For the development of technological maps as initial data and documents, it is necessary:
- working drawings;
– building codes and regulations (SNiP, SN, VSN, SP);
- instructions, standards, factory instructions and specifications (TS) for installation, commissioning and commissioning of equipment;
— unified norms and prices for construction and installation works (ENiR, GESN-2001);
- production norms for the consumption of materials (NPRM);
- local progressive norms and prices, maps of labor organization and labor processes.
Working flow charts are reviewed and approved as part of the PPR by the head of the General Contracting Construction and Installation Organization in agreement with the Customer's organization, the Customer's Technical Supervision and the organizations that will be in charge of the operation of this building, structure.
1.7. The use of the TTC helps to improve the organization of production, increase labor productivity and its scientific organization, reduce costs, improve quality and reduce the duration of construction, safe performance of work, organization of rhythmic work, rational use of labor resources and machines, as well as reducing the time required for the development of PPR and unification of technological solutions .
The scope of work performed sequentially during the installation of foundations includes:
- geodetic breakdown of the location of the foundations;
— preparation of the base for the installation of foundations;
- installation of foundation blocks;
- alignment and fixing of the foundations in the design position.
Work should be carried out in accordance with the requirements of the following regulatory documents:
#M12291 5200023SNiP 3.01.01-85#S*. Organization of construction production;
#M12291 871001100
SNiP 3.03.01-87#S. Bearing and enclosing structures;
#M12291 901794520
SNiP 12-03-2001#S.
Labor safety in construction. Part 1. General requirements;
#M12291 901829466
SNiP 12-04-2002#S. Labor safety in construction.
Glass-type foundation device
Part 2. Construction production.
2. ORGANIZATION AND TECHNOLOGY OF WORK PERFORMANCE
2.1. In accordance with #M12291 5200023SNiP 3.01.01-85#S* "Organization of construction production", before the start of construction and installation (including preparatory) work at the facility, the General Contractor is obliged to obtain permission from the Customer to perform installation work in the prescribed manner.
The basis for the start of work can be the Act of Interim Acceptance of Critical Structures of an Open Pit for Foundations.
2.2. The installation of foundation blocks is carried out in accordance with the requirements of SNiP, relative to the marking axes in two mutually perpendicular directions.
2.3. Prior to the installation of foundations, the general contractor must complete all preparatory work, including:
— construction of temporary roads and entrances;
- excavated foundation pit;
— the center axes of the building are determined and fixed;
— set benchmarks;
— designs that passed the input control were selected;
- the required structures were delivered and laid out in the crane operation area;
— sites for storage of prefabricated structures were planned and prepared;
— the necessary mounting means, devices and tools were delivered to the installation area.
Acceptance of the object for installation must be carried out by employees of the installation organization according to the act.
Foundation blocks are stored on open, planned sites with a coating of crushed stone or sand (H = 5 + 10 cm) in stacks, with a total height of up to 2.5 m.
The gaskets between the blocks are stacked one above the other strictly vertically, otherwise cracks form in the products and they can collapse. The cross section of gaskets and linings is usually square, with sides of at least 25 cm. The dimensions are selected so that the overlying blocks do not rest on the protruding parts of the underlying ones.
The storage areas are separated by through passages with a width of at least 1 m every two stacks in the longitudinal direction and every 25 m in the transverse direction.
To pass to the ends of the products, gaps equal to 0.7 m are arranged between the stacks.
2.5. Before installing the foundation blocks, the following work must be done:
- break down the places of their installation;
- put on four faces at the level of the upper plane of the foundations the risks of the installation axes in accordance with the project;
- put the risks of the installation longitudinal axes on the side faces at the level of the bottom of the foundation block.
2.6. To lay out the installation sites of the foundations along the perimeter of the workshop building or only at its corners, a cast-off 1 is installed, a wire 3 is pulled, indicating the position of the axes 4, and using plumb lines 5, the points of their intersection are transferred to the bottom of the pit, where they are fixed with pegs 6 hammered into the ground (see Fig.1).
Geodetic breakdown of foundation installation sites
1 - cast-off; 2, 8 - risk; 3 - wire; 4 - the position of the center axes on the cast; 5 - plumb; 6 - pegs; 7 - foundation
The design position of the outer face of the blocks is measured from the points. Additional and intermediate axles are marked with a metal tape measure (see Fig. 2).
Breakdown of faces of foundation blocks
2.7. On glass-type foundations, the middle of the side faces of the glass is determined and axial risks are applied to the upper face.
The risks are applied with a pencil or marker. When lowering the foundation block onto the base, its position is controlled by risks.
The design position of the base marks is set using a level. So that the foundation blocks do not hang from the sand cushion, its width is made 200-300 mm larger than the size of the base of the foundations.
The base, prepared for the installation of the foundation, must be accepted according to the act of examination of hidden works.
The effectiveness of the installation of foundations largely depends on the installation cranes used. The choice of a crane for installation depends on the geometric dimensions, weight and location of the blocks to be mounted, the characteristics of the installation site, the volume and duration of installation work, the technical and operational characteristics of the crane.
The feasibility of erecting building structures with one or another crane is established according to the installation flow diagram, taking into account the lifting of the maximum possible number of mounted structures from one parking lot with a minimum number of crane permutations.
When choosing a crane, the path of movement along the construction site and the places of its parking are also determined (see Fig. 3).
Fig.3. Determination of the main characteristics of the crane by a graphical method
W - step; P is the span; d
- the length of the displacement of the crane; - distance from the support to the edge
2.10. Mounted structures are characterized by the mounting mass, mounting height and the required reach. For the installation of foundation blocks, self-propelled jib cranes are used. The choice of a mounting crane is made by finding three main characteristics: the required hook lifting height (mounting height), lifting capacity (mounting weight) and boom reach.
For installation, we select an automobile crane with a lifting capacity of 25 tons based on a KAMAZ vehicle of the KS-55713-4 brand. The lifting capacity of the crane at a given height and the reach of the cargo hook is found by the formula:
- mass of the mounted element, t; - mass of rigging equipment (traverse slings, grips, etc.).
The load characteristics of the crane are shown in the graph (see Fig. 4).
Crane capacity chart depending on the presence and reach of the boom
2.11. The foundation blocks are installed on a layer of sand leveled to the design mark immediately in the design position in order to avoid disturbing the surface layer of the base. Installation of foundation blocks on bases covered with water or snow is not allowed.
Foundation glasses and supporting surfaces must be protected from contamination.
For large industrial or agricultural facilities with an area of 5-6 thousand square meters. m pouring a deep strip foundation is unprofitable. In this case, the installation of a glass-type foundation is more suitable - a more serious version of a columnar base.
Glass type foundation - its features, advantages and scope
The glass foundation is designed to evenly distribute the large weight of the building at the fulcrum. It is used in the construction of buildings and structures based on columns. Thus, such a foundation is suitable for:
- cowsheds, poultry houses, stables and other livestock facilities;
- hangars, warehouses and commercial premises;
- entertainment and sports facilities;
- cell towers and power lines;
- underground parking lots and garages.
Pros and cons of glass foundation
This type of foundation is characterized by undoubted advantages:
It is important to remember that the advantages of using a glass-type base appear only if all building standards and regulations are observed:
There are also disadvantages to this type of foundation:
- not suitable for heaving and swampy soils - only for dense soils with deep groundwater;
- the use of heavy equipment - you can’t do without a jib crane and an excavator;
- high price - mainly due to equipment rental;
- construction speed - it will take about two months to fill and solidify monolithic glasses on the spot, while manufacturing factory blocks takes a month, and their installation is another week.
But there may be problems with the delivery of heavy reinforced concrete blocks, so you need to first take care of filling the access roads with gravel. Otherwise, after the rains, the trucks may not reach.
Can it be used in private construction?
As already mentioned, such a foundation is not suitable for the construction of a country house - because of the high cost. But if you fill small "glasses" immediately on site, you can achieve significant savings due to the reduction in material costs. In addition, a crane is not needed, since the columns can also be made monolithic, and shallow pits are easily dug by hand.
The undoubted advantage of a glass-type foundation in private construction is the ability to build on sites with a large height difference without leveling the site. And, unlike the foundation of piles, such a foundation is suitable for soils without lateral support - sandy and sandy loam.
There you can equip a garage, workshop or technical rooms such as a laundry. The only thing is that on a sloping site you will have to seriously work on waterproofing the basement, otherwise during the rains all the water from the slope will collect there.
Step-by-step instructions for installing a glass-type foundation
It is possible to start building a glass-type foundation only after creating a project accurately calculated by specialists. In this project, the type of load should be taken into account: for the central, base plates of square section are used, for the side - rectangular. The type of shoe and its section depend on the soil and the bearing capacity of the foundation.
But regardless of size and type, the foundation must be made of M200 concrete with moisture absorption up to 5% maximum of its own volume (indicated by the B2 marking). For reinforcement, class A2 or A3 reinforcement for welded structures is used.
Installation of the foundation from prefabricated blocks
The first thing that starts any construction is the provision of an access road to the facility. You should not save on gravel - the weight of each block varies from 1.3 to 5.8 tons, so heavily loaded trucks may not drive through the dirt road after rains. When a crane, an excavator and all materials are delivered to the construction site, you can proceed to the foundation:
- Pit pits are dug for glass blocks according to the developed project. First with an excavator, and then they are manually leveled with shovels.
- At least 30 cm of a sand and gravel cushion must be poured onto the bottom, which should be 30 cm larger than the future base slab. First, gravel, which is rammed and leveled. Then a layer of moistened sand of the same thickness. If sand is poured from a hose, you need to be extremely careful not to wet the earthen bottom.
- If the bottom of the pit and the sand cushion are not level, the weight will not be evenly distributed.
- According to the project, a central point is marked for each pit, according to which the position of the base plate and shoe will be verified. Using a crane, the blocks are transferred to the pit, and two builders on weight align them according to the markup, and then the crane lowers the block.
- The foundation beam is laid on the glasses between the columns - it does not require additional pouring of the strip foundation. And already on this beam a concrete wall panel will be placed.
The installation speed of finished glasses is really impressive - you can put up to 130 glasses in a week and immediately start building walls, without waiting for the foundation to solidify, as happens when pouring.
The device of a monolithic foundation
Despite the fact that the cost of finished glass blocks is not so high, almost all the monetary benefit is offset by the complex and expensive delivery of multi-ton shoes. In some cases, it is much easier to pour the foundation on site by ordering several ready-mixed concrete mixers. It is not worth mixing concrete on your own - you will not be able to achieve the desired grade. The device process is not very different from the installation of finished blocks:
- Pit pits are dug, the bottom is leveled, a sand and gravel cushion is laid and rammed.
- A reinforcing frame for the future glass is installed on the footing. Reinforcement can only be welded with the appropriate marking, if the reinforcing bars are not intended for welding, they are tied with a wire.
- A formwork is installed around the reinforcement, repeating the shape of the glass block. If it is planned to install iron columns, instead of an empty niche inside the shoe, a monolithic glass is made with embedded anchors made of high-strength metal.
- When the formwork is ready, you can start pouring concrete. Do not forget to vibrate the concrete with a submersible vibrator until the air bubbles rising from the depths completely disappear. If this is not done, under the weight of walls and ceilings, the base may begin to crack.
- The formwork is removed after the concrete hardens - approximately on the third day after pouring. The concrete gains residual strength only after a month, all this time the foundation needs to be watered and covered.
Only after the foundation has hardened sufficiently, you can start backfilling and installing the columns.
To understand the process, the video shows how a similar type of foundation is poured:
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