Foundation pit for a glass-type foundation. Building a glass foundation

The main type of foundations arranged under the columns are monolithic reinforced concrete foundations, including a stepped slab part and a pillar. The pairing of prefabricated columns with the foundation is carried out using a glass (see Fig. 4.1, a), monolithic - by connecting the reinforcement of columns with outlets from the foundation (Fig. 4.8, a), steel - by fastening the column shoe to anchor bolts concreted in the foundation (Fig. 4.8, b).

Rice. 4.8.

a- monolithic; b- steel; one - reinforcing mesh; 2 — anchor bolts

Sole dimensions ( b,l), steps ( b 1 , l 1 ), sub-column ( l uc , b uc) are taken as multiples of 300 mm; step height ( h 1 , h 2) - multiple of 150 mm; foundation height ( hf) is a multiple of 300 mm, the height of the slab part ( h) is a multiple of 150 mm.

TABLE 4.22. HEIGHT OF FOUNDATION STEPS, mm

Plate height foundation h, mm	h 1	h 2	h 3
300	300	-	-
450	450	-	-
600	300	300	-
750	300	450	-
900	300	300	300
1050	300	300	450
1200	300	450	450
1500	450	450	600

The modular dimensions of the foundation are as follows:

hf	1500—12000
h	300, 450, 600, 750, 900, 1050, 1200, 1500, 1800
h 1 , h 2 , h 3	300, 450, 600
b	1500—6600
l	1500—8400
b 1 , b 2	1500—6000
buc	900—2400
luc	900—3600
l 1 , l 2	1500—7500

The height of the steps is taken according to the table. 4.22 depending on the height of the slab part of the foundation. The removal of the lower stage is calculated by the formula c 1 = kh 1 , where k- coefficient taken according to the table. 4.23.

Guidelines for the design of foundations on a natural basis for columns of buildings and structures of industrial enterprises

The shape of the foundation and the under-column in plan is taken: with a central load - square, dimensions b×b and b uc × b uc; with an eccentric load - rectangular, with dimensions b×l and b uc×l uc, relation b/l is 0.6-0.85.

Dimensions of foundations for standard columns of rectangular section, for example, according to the KE-01-49 and KE-01-55 series, for one-story industrial buildings are accepted according to series 1.412-1/77. The letters in the brands of foundations indicate: F - foundation; A, B, C and AT, BT and VT - the type of under-columns for ordinary foundations and for expansion joints (Table 4.24), and the numbers characterize the standard size of the sole of the slab part of the foundation and its standard size in height.

TABLE 4.23. COEFFICIENT k

Ground pressure, MPa	Values k with concrete class
	AT 10 O'CLOCK	B15	IN 20	AT 10 O'CLOCK	B15	IN 20	AT 10 O'CLOCK	B15	IN 20	AT 10 O'CLOCK	B15	IN 20
0,15	3	3	3	3	3	3	3	3	3	3	3	3
0,2	3	3	3	3	3	3	3	3	3	2,9	3	3
										3
0,25	3	3	3	3	3	3	3	3	3	2,5	2,8	3
										2,6	3
0,3	3	3	3	3	3	3	2,7	3	3	2,3	2,5	3
							2,8			2,4	2,6
0,35	2,8	3	3	2,7	3	3	2,4	2,7	3	2,1	2,3	2,7
	3			2,9			2,6	2,9		2,2	2,4	2,9
0,4	2,6	2,9	3	2,5	2,8	3	2,3	2,5	3	2	2,1	2,5
	2,7	3		2,7	3		2,4	2,7			2,2	2,6
0,45	2,4	2,7	3	2,3	2,6	3	2,1	2,3	2,8	1,9	2	2,3
	2,5	2,8		2,5	2,7		2,2	2,5	3		2,1	2,5
0,5	2,3	2,5	3	2,2	2,4	3	2	2,2	2,6	1,8	1,9	2,2
	2,4	2,7		2,3	2,6		2,1	2,3	2,8		2	2,3
0,55	2,2	2,4	2,8	2,1	2,3	2,7	1,9	2,1	2,5	1,7	1,8	2,1
	2,3	2,5	3,8	2,2	2,4	2,9	2	2,2	2,6		1,9	2,2

Note. Above the line is the value without taking into account crane and wind loads, below the line - with these loads.

TABLE 4.24. DIMENSIONS OF THE UNDER-COLUMN PART OF THE FOUNDATIONS

Column dimensions, mm		ordinary foundation						Cup sizes, mm			Cup volume, m 3
lc	bc	sub-column type Nika	dimensions, mm		sub-column type Nika	sizes, them		hg	lg	b g
			luc	buc		luc	buc
400	400	BUT	900	300	AT	900	2100	800 900	500	500	0,22 0,25
500 600 600	500 400 600	B	1200	1200	BT	1200	2100	800 900 800	600 700 700	600 500 600	0,31 0,34 0,41
800 800	400 500	AT	1200	1200	WT	1500	2100	900 900	900 900	500 600	0,44 0,52

The following dimensions are accepted for height: type 1 - 1.5 m; type 2 - 1.8 m; type 3 - 2.4 m; type 4 - 3 m; type 5 - 3.6 m and type 6 - 4.2 m. 4.25 and 4.26 are given as an example sketches and dimensions of ordinary foundations and foundations for expansion joints. These foundations can be used with a design base resistance of 0.15-0.6 MPa.

All dimensions of the foundations are taken as multiples of 300 mm. Concrete class B10 and B15 is used. Reinforcement is carried out with flat welded meshes of reinforcement classes A-I, A-II and A-III. protective layer concrete is adopted with a thickness of 35 mm with a simultaneous preparation device with a thickness of 100 mm from concrete B3.5.

TABLE 4.25. DIMENSIONS OF ROW FOUNDATIONS

Sketch	Foundation brand	Dimensions, mm							The volume of concrete, m 3
		l	b	l 1	b 1	h 1	h 2	hf
	FA6-1 FA6-2 FA6-3 FA6-4 FA6-5 FA6-6	2400	2100	1500	1500	300	300	1500 1800 2400 3000 3600 4200	2,9 3,2 3,6 4,1 4,6 5,1
	FA7-1 FA7-2 FA7-3 FA7-4 FA7-5 FA7-6	2700	2100	1800	1500	300	300	1500 1800 2400 3000 3600 4200	3,2 3,3 4,0 4,5 4,9 5,4
	FA8-1 FA8-2 FA8-3 FA8-4 FA8-5 FA8-6	2700	2400	1800	1500	300	300	1500 1800 2400 3000 3600 4200	3,5 3,7 4,2 4,7 5,2 5,7
	FA9-1 FA9-2 FA9-3 FA9-4 FA9-5 FA9-6	3000	2400	2100	1500	300	300	1500 1800 2400 3000 3600 4200	3,8 4,1 4,6 5,0 5,5 6,0

TABLE 4.26. DIMENSIONS OF FOUNDATIONS UNDER EXPANDED JOINTS

Sketch	Foundation brand	Dimensions, mm						The volume of concrete, m 3
		b	l	b 1	h 1	h 1	hf
	FAT3-1 FAT3-2 FAT3-3 FAT3-4 FAT3-5 FAT3-6	1800	2100	-	300	-	1500 1800 2400 3000 3600 4200	3,4 4,0 5,1 6,2 7,4 8,5
	FAT6-1 FAT6-2 FAT6-3 FAT6-4 FAT6-5 FAT6-6	2400	2100	1500	300	300	1500 1800 2400 3000 3600 4200	4,2 4,7 5,9 7,0 8,1 9,3
	FAT7-1 FAT7-2 FAT7-3 FAT7-4 FAT7-5 FAT7-6	2700	2100	1800	300	300	1500 1800 2400 3000 3600 4200	4,5 5,1 6,2 7,4 8,5 9,6

Rice. 4.9. Foundation with concrete footing for supporting beams 1 - foundation; 2 - footing; 3 - column

To support the foundation beams, a footing is provided (Fig. 4.9). An example of a constructive solution for the foundation is shown in fig. 4.10.

Dimensions monolithic foundations for standard columns with a two-branch section, in particular for the KE-01-52 series of one-story industrial buildings, they are accepted according to the 1.412-2 / 77 series. The dimensions of the under-column part of such foundations are given in Table. 4.27. The dimensions of the slab part have sizes from 1 to 18, as well as size 19, in which the size of the sole is 6 × 5 m. The height of the foundations can be of type 1-6. Other parameters are the same as in series 1.412-1/77.

Rice. 4.10.

1-6 - reinforcing mesh

Reinforced concrete foundations for typical rectangular columns, for example, according to the II-04, II-20 and 1.420-6 series for multi-storey industrial buildings, are accepted according to the 1.412-3/79 series.

TABLE 4.27. TYPES AND DIMENSIONS OF UNDER COLUMNS

Column dimensions, mm		ordinary foundation			Foundation for expansion joints			Cup sizes, mm			Cup volume, m 3
lc	bc	sub-column type nicknames	dimensions, mm		sub-column type nicknames	dimensions, mm		hg	lg	b g
			luc	buc		luc	buc
300	300	BUT	900	900	AT	900	2100	450 450	400	400	0,08 0,12
400	400							650 1050	500	500	0,18 0,29
600	400	B	1200	1200	BT	1200	2100	650 1050	700	500	0,25 0,40

The difference in the marking of foundations compared to other series is that after the number indicating the standard size of the sole, the height of the slab part is given. The dimensions of the under-column part of the foundation are given in Table. 4.27. The dimensions of the slab part include sizes from 1 to 18 and size 19 (with a base size of 5.4×6 m). in height, the foundations can be of the 1st-6th type. Other parameters are the same as in series 1.412-1/77. Monolithic reinforced concrete foundations for reinforced concrete standard half-timbered columns of rectangular section, in particular, according to codes 460-75, 13-74 and 1142-77, are accepted according to series 1.412.1-4. The dimensions of the foundations are given in table. 4.28. The connection of the column with the foundation is articulated. The foundations are designed for a pressure of 0.15-0.6 MPa. Concrete class B10 is used. Reinforcement is carried out with welded meshes of reinforcement of classes A-I, A-II and A-III. An example of a node for supporting a column on a foundation is given in fig. 4.11.

Under the columns of buildings, prefabricated foundations of one or more elements are used. in fig. 4.12 shows solutions for prefabricated foundations for frame columns for multi-storey public and industrial buildings from elements of the 1.020-1 series. Foundation elements of type F are used on a natural basis, type FS - for composite foundations (Table 4.29). The thickness of the concrete protective layer of the lower working reinforcement is assumed to be 35 mm, and the rest of the reinforcement - 30 mm. The depth of embedding the column in the foundation must be at least the values ​​\u200b\u200bgiven in Table. 4.30.

Rice. 4.11.

1 - embedded product of the column; 2 - anchor; 3 - connecting element

The foundation is the basis of any building, regardless of what it is for. It can be a residential building - one-story or multi-level, an industrial facility, a warehouse-type building, a commercial building, or the most common outbuilding. Used in construction different types grounds. Most often used tape or slab. Such a base, completely filled and solid, is applicable on any soil. But for the construction of industrial buildings, you can use a glass-type foundation.

Characteristics of the glass base

This type of building foundation is qualitatively different from the often used foundation tape or monolithic slab. This is a dotted non-solid base, which takes on part of the load created by the building and distributes it in separate places where the pressure is greatest.

For the construction of large, but low objects, mainly for industrial purposes, a foundation is used for glass-type columns. These are prefabricated concrete structures located in pre-designed places in the form of "steps". If the sole is the support of the tape, then a reinforced concrete product is used for the glass. The shape of such a foundation actually resembles trapezoidal steps, which are increasingly narrowing towards the top of the structure.

Where is glass foundation used?

For the individual construction of low-rise residential buildings, as well as the complex construction of multi-level new buildings, only tape or monolithic foundations are used. It is impossible to use a dotted glass base in this case. It should be used for the construction of the following buildings:

• industrial facilities - bridges over water bodies, structures for crossings and crossings over railway tracks;
• social infrastructure premises - underground garages and car parks;
• engine rooms at thermal power plants and power plants;
• warehouse hangars for storage of finished products or raw materials;
• sports and shopping malls single-level type with a low weight of the structure.

Most often, the columnar base is a reinforced concrete glass-type foundation. Its main difference is that usually state structures, municipal authorities or large industrial enterprises act as the customer of the structures. This implies full compliance of the grounds with the declared technical requirements and GOSTs. To characterize the material used in the construction, as well as the place where the glass base can be located, a specially designed series of foundations of a certain version, approved and verified by design institutes, is used. The series clearly spells out all the norms and requirements that the foundation must comply with.

The composition of the glass foundation

Its constituent elements are the following prefabricated parts:

• base plate, which should be installed on a crushed stone-sand cushion located at the bottom of the dug pit;
• podkolonnik, it is he who has the shape of a glass;
• a column that serves as a supporting element of the frame structure;
• a concrete pillar needed to support the support beams under the frame walls.

The device of the glass-type foundation completely depends on the scope of the future structure, its weight, dimensions. It is allowed to erect this foundation for multi-storey construction, if the soil under the foundation is stable, not heaving and not loose. "Glasses" are used on solid, immovable soil with deep groundwater.

Benefits of using a glass base

1. Structures are made of heavy reinforced concrete, but total weight of the finished structure presses on the soil with a minimum load due to its point location on the ground.
2. Installation is relatively quick, since all elements are prefabricated and have mounting loops. It requires the use of special construction equipment to lift heavy parts, but installation time is still kept to a minimum.
3. Prefabricated foundations claim a high service life, which can reach one hundred years, subject to construction technology.
4. Water absorption is very low because the contact area with the soil is small. The whole structure is located on a monolithic slab, which does not allow moisture to adversely affect the base.
5. The reliability of the glass foundation is due to the competent and uniform distribution of transverse and longitudinal loads.
6. Since the structure is prefabricated, it is easy to move it if necessary.
7. Acceptable cost. If you want to build a building of a very large area, then the cost of erecting a tape-type base will be enormous. The tape is continuous and runs along the entire perimeter of the structure. And the use of a columnar base can significantly reduce costs.

Step-by-step guide to raising glasses

Installation of columnar foundations occurs with the obligatory use of construction equipment - excavators, cranes, winches.

1. A preparatory process aimed at thoroughly cleaning the surface under the foundation. It must be even. Digging a pit of a given size. The laying level of a monolithic slab should not be less than one meter, as in the case of sealing the sole of a strip base.
2. Tamping the trench with gravel and sand. Thanks to this, you can get a fairly flat and uniform surface.
3. The columnar foundation should be erected using building measuring tools, constantly monitoring the horizontal and vertical prefabricated structures. You need to use a level and a level.
4. Mandatory breakdown and marking with the help of pegs of the prepared bed of axes, on which each individual glass will be located.
5. Glasses that have already been delivered to the construction site should be cleaned of possible debris. With the help of a crane, the elements are captured by the mounting loops and delivered to the monolithic support. You should center the position of the glass and slowly place it on the prepared place. The risk match is checked.
6. Guiding a kind of grid with a thread between really located elements.
7. Precast concrete foundations require constant inspection with a surveying instrument. After each installation of the glass, measurements must be taken.
8. The soil that has been excavated is poured back into the pit to the top of the block. After that, the support beams are installed on glasses or on special posts. The dimensions of the pit completely depend on the type of building and its area. Sometimes it is necessary to dig out a large amount of land if large-scale construction is planned.

Under the columns of industrial buildings, steel, reinforced concrete or wooden wedges are used, located around the element, two from each side. Their use is mandatory. They support the column during the concreting process. Later, the wooden wedges are removed, and the steel ones are not touched for greater strength of the reinforcement.

The installation of glass-type foundations is focused on the constant leveling of the surfaces of prefabricated elements. The slightest displacement cannot be allowed, since the entire structure is a frame made of heavy concrete. When working, all design calculations must be observed. Those products that do not meet the standards and GOST should not be used. This may not be safe.

All work related to the design, carrying out the necessary measurements, soil analysis using special geodetic equipment should be carried out in strict compliance with the norms and requirements that apply to the columnar foundation. Most often, reinforced concrete prefabricated parts are used for the foundation. The calculation of their strength and composition is performed at the factory. Doing work technical specialists, therefore, products are simply required to comply with the stated design requirements.

Some features of the columnar foundation of glass type

In order for the products to be very durable in the manufacture of glasses, monolithic slabs and columns use reinforcing metal rods. This securely fastens the elements. In addition, reinforcement occurs at the stage of installation of columns. When they are concreted into the bottom of the glass, the steel bars are not removed when pouring concrete, but left inside the glass for greater strength of the finished structure.

The construction of a glass foundation is very different from the installation of a strip base. For the columnar type, prefabricated parts are used, made directly at the factory, therefore, the formwork for work is necessary when fixing the glass - nest former. It is sheathed with a metal sheet and poured with concrete to the design mark. The column is installed directly in the bottom of the glass and a fairly reliable lock is formed.

For the construction of industrial facilities, you can use not only prefabricated, but also monolithic columnar foundation glass type. It is a more powerful stepped structure, which is able to withstand a very large load and significant weight of the structure. The steps and their height completely depend on the dimensions of the proposed building. Columns are tied to coordinate axes. Monolithic structures have some advantage, because they are able to more "unload" the pressure on the base.

Concreting of all elements is necessary condition careful construction of the building. The prefabricated parts themselves are made of heavy concrete, it is imperative to use a reliable reinforcing mesh. Concrete is taken of high quality, usually a grade not lower than M200V2 is used so that the structure can withstand the pressure of a building under construction. Concrete structures can be involved in construction only after they have gained high strength.

The foundation beam is an integral element of the foundation. It is located on the columns resting against the sub-columns. The load-bearing walls of the building should be located on these beams. You can also install beams on column consoles. The conjugation of the glass-type foundation with the foundation beam must be strong. This is achieved by concreting and high-quality metal reinforcement of the finished structure.

Installation of column elements

Columns transported in advance to construction site, you need to decompose so that the equipment can easily and without unnecessary movements get to them and install these elements. Columns are measured to determine where to carry out the sling grab and lift.

Proper installation of columns includes a system for applying marks. The crane moves along the row and can install two columns at once in one parking lot. The alignment of the columns and the base must be perfect so that subsequently the beams do not shift.

Install support beams. Carry out a new markup and check the design values ​​of the location of the columns. After that, clean mounting elements, the beams are fixed with ropes, lifted and slowly hung over the column, lowering the beam to the stop very carefully and in accordance with the risks.

The beams are pre-attached to the bolts, the alignment of the entire structure is checked again, and only after that the columns are carefully strengthened in the console.

The foundation of the glass type under the columns is sometimes even used for the construction of cottages, the large terrace of which goes, for example, directly to the water. It is very comfortable and beautiful. The use of the glass base is quite wide, but in individual construction it has some limitations.

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 living 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. 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 the production of large outbuildings, underground parking.

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 it will, for example, stand apartment house, 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 the utmost responsibility.

Strong, reliable and durable glass type foundation used for arranging collectors of the through-flow and semi-through type. Columns of the required height are installed inside it, taking on the pressure from the weight of the floor slabs and soil, evenly distributing the load on the base of the entire structure.

For ease of use foundation cups along the perimeter they are equipped with reinforcing outlets, which allow the structures to be installed in concrete floors, forming a single bearing coating. This method increases the span of the collector, allowing a larger volume of pipelines to be placed inside it or pipelines of large diameters to be located. concrete column It is made of high-strength concrete grades, and a strong steel reinforcement base provides a stable and strong foundation base.

The glass-type foundation can be used to support columns made of metal or reinforced concrete. Compared to other types of foundations, glass-type foundations differ more high rates strength, normalized size and quick installation in a short time. Monolithic reinforced concrete pillow increases bearing capacity and stability of the entire structure, allowing it to withstand significant loads.

Product Benefits

Foundations for arranging collectors have the following characteristics:

• products provide fast and reliable laying of underground heating mains, engineering networks and systems;
• reinforced concrete columns not afraid of negative impacts environment: they are resistant to chemical environments, moisture, temperatures;
• products are immune to vibrations, which allows them to be used for laying networks under highways;
• different standard sizes of foundation sleeves are designed to accommodate underground collectors of any design features.

We offer an extensive range concrete columns, price they are available to individual developers, municipal organizations, construction companies. To order products for engineering infrastructure, in the required volume, leave a request on the website or call by phone. Shipment of orders is carried out by our vehicles or on a self-delivery basis.

Concrete grade: M300 (F150; W6); GOST 13015-2012
On request it is possible to manufacture
reinforced reinforcement option.

Multi-storey frame-panel houses are built on special columnar foundations. They differ from monolithic ones, which are arranged for low-rise buildings. In industrial construction, a glass-type foundation is erected for them, which is a prefabricated structure. It is arranged as follows: a factory reinforced concrete glass is installed in a pit, and a reinforced column is located in it. All elements are delivered ready-made, which reduces the time of work.

What does the glass look like?

The glass, popularly called the "shoe", has a special shape. Almost always it is a stepped square with a wide base and a narrow top. The dimensions of the foundation for the column are calculated individually for each object. However, they are controlled by GOST 24476-80 and have a standard minimum value of 1200 mm, a maximum of 2100 mm. For them, reinforced concrete columns are taken with cross section 300 mm and 400 mm.

Bases of this type have the following advantages:

• high load capacity;
• low water permeability class;
• quick installation with heavy equipment.

The device of glass foundations

Today, prefabricated foundations for columns are arranged as bases for production workshops, outbuildings, underground parking lots. Most often - for the construction of multi-storey industrial buildings of the frame type. Important: the installation of a glass foundation is possible only on soils that are resistant to subsidence and have a low degree of heaving.

The foundation consists of the following elements:

1. Plate (base).
2. Sub-column (glass).

Distinctive parameters of glass-type bases

Depending on the load and soil properties, the foundation is calculated. The designs differ in the following parameters:

• pedestal height;
• number of base slabs (1 or 2);
• method of joining the column with the "shoe".

The last parameter depends on the material of the column. For example, foundations metal columns differ in the fastening of the column to the glass in comparison with the reinforced concrete column. The connection of the reinforced concrete column with the "shoe" occurs with the help of concrete grades M200, M300. This is how it is customary to build in Russia.

Experience from other countries

In other countries, builders use their own methods of fastening. For example, in Hungary, the column is connected to the "shoe" with the help of rebar and concrete bars. In the USA, metal rod outlets are welded or anchor bolts are used. For bolts, a steel plate is installed between the base and the glass, which acts as a gasket. In Japan, the basis for the shoe is a sand cushion, enclosed in a reinforced concrete clip of the appropriate size.

Installation step by step

If prefabricated foundations are arranged for metal columns, fastening is carried out only with anchor bolts. Special anchor bolts are used, manufactured in accordance with GOST 24379.1-80. Their location must comply with design calculations, a deviation of ± 2 mm is allowed.

Installation is carried out under the control of the following parameters:

• alignment of glass axes with center axes;
• absence of deviations in the leveling layer of sand and in the supports;
• the foundation should adjoin the base with the entire area of ​​​​the sole.

Installation sequence:

1. Pit preparation.
2. Creation of a sand or gravel cushion, its ramming.
3. Installation of the glass base with a crane.
4. Placing the column (requires a crane) and fixing it in the "shoe".

Installation is carried out according to the location of the axes, which are indicated by marks along the edges of the glass. These risks are applied before starting work with indelible paint. Pivots are marked with strings and a plumb bob, or wire and nails. During the installation of the "shoe", you should ensure that the axes on the sole and the glass coincide with the center axes.