Ways to control the quality of stone work. Brickwork walls

General requirements. The laying of walls and other brick structures is carried out in accordance with the Rules for the Production and Acceptance of Works SNiP III-17-78, compliance with which ensures the required strength of the structures under construction and high quality of work.

In the process of work, the bricklayer makes sure that the brick and mortar specified in the working drawings are used, checks the dressing and masonry seams, the verticality, horizontality and straightness of surfaces and corners, the installation of embedded parts and connections, the quality of masonry surfaces (drawing and jointing, selection of bricks for outer verst of non-plastered masonry with even edges and corners).

In dry, hot and windy weather, the brick is abundantly moistened with water before laying, and the ceramic brick is immersed in water so that the mortar adheres better and its normal hardening occurs. This is especially important for masonry in seismic areas and performed on mortars with cement binders.

During breaks in work, the top row of masonry should remain uncovered with mortar. Continuation of masonry after a break must begin with watering the surface of the previously laid masonry. This requirement is due to the fact that dry brick, after laying on the mortar, quickly sucks water out of it and the water content of the mortar is insufficient for normal cement hydration. As a result, part of the binder in the solution without interacting with water remains unused, and the strength of the solution and its adhesion to the brick are sharply reduced. The need to moisten the brick before laying it in the structure and the degree of moisture is determined by the construction laboratory.

Rice. 64. Permissible deviations in masonry (shown in dotted lines):
a - walls, b - pillars

The rules for the production and acceptance of work established permissible deviations (Table 4) in the dimensions, position of stone structures (Fig. 64) relative to the center axes and design dimensions.

Table 4. Permissible deviations, mm, in the size and position of stone structures

To check the quality of the masonry, the bricklayer uses the tools and fixtures at his disposal. In cases where deviations exceed the permissible limits, the issue of continuing work is decided jointly with the design organization. If the design organization allows not to redo the masonry, it indicates specific ways to correct defects.

Rice. 65. Validation brickwork:
a - the angle between the outer and inner wall with a square, b, c - the walls with the rule and the level, d - the masonry angle with a plumb line

The correctness of laying the corners of the building (Fig. 65, a) is controlled with a wooden square, the horizontality of the wall rows is controlled by the rule and level (Fig. 65, b) at least twice on each tier of masonry. To do this, the rule is placed on the masonry, a level is placed on it and, having aligned it along the horizon, the deviation of the masonry from the horizontal is determined. If it does not exceed the established tolerance, the deviation is eliminated when laying subsequent rows.

The verticality of the surfaces of the walls (Fig. 65, c) and corners (Fig. 65, d) of the masonry is checked by the level and plumb line at least twice on each tier of the masonry. Deviations that do not exceed the permissible ones are corrected during the subsequent laying of a tier or floor. Deviations of the axes of structures are eliminated in the levels of interfloor ceilings.

Periodically check the thickness of the seams. To do this, measure five or six rows of masonry and determine the average thickness of the seam, for example, if when measuring five rows of masonry walls, its height turned out to be 400 mm, then the average height of one row of masonry will be 400: 5 \u003d 80 mm, and the average thickness of the seam minus the thickness of the brick will be 80 - 65 = 15 mm. The average thickness of the horizontal joints of brickwork within the height of the floor should be 12 mm, vertical - 10 mm. In this case, the thickness of individual vertical joints should be at least 8 and not more than 15 mm, horizontal not less than 10 and not more than 15 mm. Thickening of seams against those stipulated by the rules can be allowed only in cases stipulated by the project; in this case, the dimensions of the thickened seams should be indicated in the working drawings.

The correctness of filling the joints with mortar is checked by taking out individual bricks of the laid out row in different places (at least three times along the height of the floor).

Requirements for masonry in seismic areas. When erecting stone structures in seismic regions, increased requirements are imposed on materials and side events. The surfaces of stone, brick or block are cleaned of dust before laying. In mortars intended for the construction of masonry, Portland cement is used as a binder. Prior to the commencement of stone work, the construction laboratory determines the optimal ratio between the pre-wetting of the local wall stone material and the water content of the mortar mixture. Solutions are used with high water-retaining capacity (water separation is not more than 2%). The use of cement mortars without plasticizers is not allowed.

Masonry of bricks and ceramic slotted stones is carried out in compliance with the following additional requirements: masonry of stone structures is erected for the entire thickness of the structures in each row; horizontal, vertical, transverse and longitudinal joints of the masonry are completely filled with mortar with trimming of the mortar on the outer sides of the masonry; masonry walls in the places of their mutual adjacency are erected only at the same time; bonded rows of masonry, including backfilling, are laid out only from whole stone and brick; temporary (assembly) gaps in the masonry being erected are completed only with an inclined shtraba and located outside the places of constructive reinforcement of the walls.

Quality control. Compliance of masonry with the project and the requirements of SNiP is controlled during the receipt of materials at the construction site - input control, during the construction of structures - operational control and during acceptance - acceptance control.

1. In the process of input control control the wall materials and mortar arriving at the construction site.

Wall materials check the foreman, foreman and foreman so that they comply with the requirements of the standards in form and accuracy; promptly report to the construction laboratory about a new batch of wall material received at the construction site and participate in sampling for testing.

ready solution, delivered to the construction site must have a passport indicating the date and time of manufacture, brand and mobility. The incoming mortar (or made at the construction site) is additionally checked for the following main indicators: mobility, density, delamination and compressive strength. Such checks are made daily and with each change in the composition of the solution.

The mobility of the solution is determined at least three times per shift. The amount of mobility is determined by the depth of immersion of a reference steel cone into it.

The density of the mortar mixture is determined using a 1-liter cylindrical vessel with a nozzle.

The stratification of the mortar mixture is determined in those cases when, during transportation or storage, the mixture stratifies and its homogeneity is disturbed.

The compressive strength of the solution is determined in sample cubes 70.7 x 70.7 x 70.7 mm in size at the age specified in the specifications for this type of solution. Three specimens are made for each test period.

2. Operational control carried out by masons in the course of work. They control the correctness of transportation and filling of masonry joints with mortar, verticality, horizontality and straightness of surfaces and corners, masonry thickness, dimensions of piers and openings, etc. At the same time, the bricklayer (or inspector) is guided by the maximum permissible deviations regulated by SNiP and TU for various stone structures ( Fig. 9.25 shows the allowable deviations for a brick wall as an example).

During the masonry process, the worker or foreman must ensure that the methods of fixing the girders, beams, decks and floor panels in the walls and on the pillars are consistent with the project. The ends of the split runs and beams resting on the internal walls and pillars must be connected and embedded in the masonry; according to the project, reinforced concrete or metal linings are laid under the ends of the runs and beams.

3. In the process of acceptance of stone structures establish the scope and quality of the work performed, the compliance of structural elements with working drawings and the requirements of SNiP.

4. During the acceptance of stone structures, check: correct dressing, thickness and filling of seams; verticality, horizontality and straightness of masonry surfaces and corners;
the correctness of the device of sedimentary and temperature seams; correct arrangement of smoke and ventilation ducts; the presence and correct installation of embedded parts; superficial quality
facade non-plastered brick walls (evenness of color, observance of dressing, drawing and jointing of seams); the quality of facade surfaces lined with various types of slabs and
stones; ensuring the removal of surface water from the building and protection of foundations and basement walls from them.

Quality control during the laying process. The laying of walls and other brick structures should be carried out in accordance with the project in accordance with SNiP 3.03.01-87 “Bearing and enclosing structures. Rules for the production and acceptance of works”, compliance with the requirements of which ensures the necessary strength of the structures under construction and high quality of work.

Foundation laying

Before laying the foundations, the foreman is obliged to personally check the correctness of the geodetic breakdown of the axes of the building, inputs and routes, the installation of benchmarks indicating the marks of the base of the foundations, as well as the quality of the preparation of the foundation.

When laying out the axes of a building, the linear dimensions of which do not exceed 10 m, deviations in its length and width should not exceed 10 mm, and buildings with dimensions of 100 m and more - 30 mm. For intermediate sizes, tolerances are set by interpolation. To check the correct breakdown of the axes of the building, as well as to control the production of stone work, it is necessary to have a set of control and measuring tools.

The foundations of residential buildings are made of rubble stone, rubble concrete, brick and other stones, and more recently, as a rule, from large concrete and reinforced concrete blocks.

Rubble masonry is made "under the bay" and "under the shoulder blade". Masonry "under the bay" is allowed for buildings with a height of no more than two floors. Laying is carried out from torn stone in horizontal rows 15-20 cm high, at odds with the walls of trenches or formwork without laying out verst rows, but with cracked voids. The formwork is installed in the trench after excavation is completed. In the event that the soil is dense, it is recommended to carry out laying without formwork - at odds with the walls of the trench.

In the presence of bedded stones, the rubble masonry is carried out “under the shoulder blade” in horizontal rows up to 30 cm high with the selection of stones in height, their pinning, splitting voids and observing the dressing. The first row, when laid on sandy soil or on a prepared base, is laid out dry from large bedding stones, followed by careful splitting, tamping and pouring with a liquid solution. Verstovy rows, corners and intersections of the foundations are laid out from large, more bedded stones.

To facilitate control over the correctness of the outline of the cross-section of foundations and walls, especially when laying in trenches, wooden templates are installed at least 20 m apart. The inner edges of the template boards must match the profile of the foundation. On the template boards, the laying rows are marked, along which the mooring is pulled. On the same templates, the top and bottom are marked, the holes left in the foundations for laying sewer pipes, water pipes, etc. Thus, the templates simultaneously perform the function of ordering.

The foreman or foreman is obliged to especially carefully check the correctness of the device in the foundations of sedimentary joints and junctions with existing buildings. The ingress of surface and groundwater into the basement through sedimentary joints should be excluded by the construction of a clay castle, blind area or other measures provided for by the project.

The laying of the rubble walls of the basements is carried out simultaneously with the internal brick lining of 1/2 bricks. Breaks in work with rubble masonry are allowed only after filling the gaps between the stones of the last laid out row with mortar. The surface of the stones of this row is covered with mortar only when work is resumed on the next rows of masonry. During breaks in work in dry, hot, windy weather, it is necessary to ensure that the rubble masonry is protected from drying out. To do this, the masonry is watered 3-4 times during the day or covered with roofing paper, glassine, shields, etc. Before resuming work, the masonry is cleaned of debris, and, if necessary, moistened. Before laying the basement, the upper row of the masonry of the erected foundation is leveled along the level and the correctness of the previously made breakdown of the axes of the building is checked with a theodolite.

Rubble concrete masonry is produced by embedding rubble stones into the laid concrete. The volume of rubble stone should be half the volume of concrete laid. For rubble concrete masonry, the same stones are used as for rubble masonry; cobblestone is allowed to be used unsplit. Before the start of laying, formwork is installed and scaffolding is arranged at such a level that the rubble stone does not have to be raised above 0.6 m. It is recommended to use collapsible shield formwork. This increases its turnover, facilitates installation and removal.

With rubble concrete masonry, concrete is laid in horizontal layers no more than 25 cm thick. Stones up to one third of the thickness of the structure should be embedded immediately after concrete is laid; stones are sunk to a depth of at least half of their height with intervals of 4-6 cm between them. Usually, rubble concrete masonry is compacted by layer-by-layer vibration. The mobility of the concrete used is 5-7 cm. For small volumes of work, vibration can be dispensed with by using plastic concrete with a mobility of 8-12 cm. The quality of the concrete used is controlled by the construction laboratory.

A break in the production of work during rubble concrete masonry is allowed after the stones are laid in the laid concrete layer so that after the break, the masonry begins with the laying of concrete. The surface of the previously laid masonry is pre-cleaned of debris and, if necessary, moistened. The foreman, together with the laboratory workers, must ensure that the exposed surfaces of the freshly laid masonry are moistened in dry, hot or windy weather, and that the rubble concrete structures are loaded with the full design load only when the rubble concrete reaches the design strength.

The foreman or foreman, when controlling the quality of the work performed, should be guided by SNiP 3.03.01-87 and ensure that the deviations in the dimensions and position of stone structures made of rubble and rubble concrete do not exceed those indicated in Table. 1 values.

Table 1

The following deviations of the surfaces and corners of the masonry from the vertical by one floor with a height of 3.2-4 m are allowed: walls - 20 mm, pillars - 15 mm; for the whole building: foundations - 20 mm, walls and pillars - 30 mm. Deviations of masonry rows from the horizontal are allowed for every 10 m of length: in foundations - by 30 mm, in walls - by 20 mm. Permissible irregularities on the vertical surface of the masonry are detected by applying a rail 2 m long; on plastered and non-plastered walls and pillars - 15 m, on non-plastered foundations - 20 mm. The verticality of the surfaces and corners of the masonry, as well as the horizontalness of its rows, is checked at least twice per 1 m of masonry height.

For laying foundations and plinths from hewn and artificial stones it is recommended to use limestone and concrete stones made on clinker binders. The use of stones made with air binders (for example, gypsum) is not allowed. As aggregates for the manufacture of concrete stones, gravel and crushed stone of natural rocks, crushed stone of strong and stable blast-furnace slags, as well as brick and ceramic crushed stone are used. For laying foundations and plinths of buildings, ordinary clay bricks can also be used, and for plinths of buildings above the waterproofing layer, hollow clay bricks of plastic pressing can be used.

Laying of artificial and processed natural stones of the correct form is carried out on a mortar with a mobility of 9-13 cm. The mortar is laid in an even layer in horizontal seams. Vertical seams are filled with a liquid solution. The average thickness of horizontal joints in concrete masonry is 12 mm, and in natural masonry - 15 mm.

The average thickness of vertical joints for masonry of concrete stones should be 10 mm, and for masonry of natural stones of the correct form - 15 mm. In masonry of concrete stones, transverse bonding is performed in every third row, and in masonry of natural stones - in every second. The foreman and foreman of the masons are obliged to ensure that the stones of the outer and inner versts are laid with an offset of the transverse vertical seams, and the brick wall cladding must be connected to the concrete masonry with rows of bricks or steel ties located at least three rows of stone masonry.

When checking the quality of masonry from concrete and other stones of the correct form, the work foreman and foreman are obliged to ensure that the actual deviations in the dimensions and position of the structures do not exceed the permissible SNiP.

The construction of foundations from rubble and rubble concrete, as well as from small concrete and other stones of the correct form, requires a lot of manual labor, since the possibility of using mechanisms in these works is very limited. At present, the development of the production of prefabricated reinforced concrete makes it possible to widely use large prefabricated concrete and reinforced concrete blocks for the construction of foundations and plinths of stone buildings with a height of five floors and more.

Deviations in the dimensions of structures from the design ones should not exceed:

Deviations of masonry surfaces and corners from the vertical should not exceed:

Deviations of masonry rows from the horizontal per 10 m of wall length should not exceed 15 mm. Irregularities on the vertical surface of the masonry, detected when laying a rail 2 m long, should not exceed 10 mm. The laying of bonded rows under the supporting parts of beams, girders, floor slabs, balconies and other prefabricated structures is mandatory for multi-row dressing of seams. Antiseptic wooden plugs should be installed in door and window openings according to the project. The size of the platform for supporting reinforced concrete structures on the walls should be according to the project.

The difference in the marks of the front surfaces of two adjacent floor slabs at the joint should not exceed with the length of the slab:

	up to 4 m	5 mm;
	over 4 m	10 mm.

In case of forced breaks, the laying should be carried out in the form of an inclined or vertical penalty. When performing a vertical stroke, reinforcement from rods with a diameter of not more than 8 mm should be laid in the seams with a distance of up to 2 m along the height of the masonry, as well as at the level of each floor. The number of reinforcement bars must be at least three in one level. The height of unreinforced brick partitions, not fastened with ceilings or temporary fastenings, should not exceed 1.8 m for partitions 12 cm thick. When laying in a wasteland, the depth of the joints not filled with mortar on the front side should not exceed 15 mm in the walls and 10 mm (only vertical joints) in the pillars.

Reinforced masonry must be carried out in compliance with the following rules:

During work, the bricklayer makes sure that the brick and mortar specified in the working drawings are used, and that the horizontal and vertical joints are well (completely) filled with mortar. It is impossible to allow hollows in vertical seams in the body of the masonry. This weakens it, reduces durability. In the course of laying, the bricklayer regularly checks the dressing and seams of the masonry, the verticality, horizontality and straightness of surfaces and corners, the installation of embedded parts and connections, the quality of the masonry surfaces and jointing, the selection of bricks for the outer verst of non-plastered masonry with even edges and corners.

To check the quality of the masonry, the bricklayer uses the tools and fixtures at his disposal.

The correctness of the completeness of filling the joints (vertical and horizontal) with mortar is checked by removing individual bricks of the laid out row in different places (at least three times along the height of the floor).

The verticality of the surfaces of the walls and the corners of the masonry is checked with a level and a plumb line at least twice on each tier of the masonry. Deviations that do not exceed the permissible ones are corrected during the subsequent laying of a tier or floor. Deviations of the axes of structures are eliminated in the levels of interfloor ceilings.

In cases where deviations exceed the permissible limits, the issue of continuing work is decided jointly with the design organization. If the design organization allows not to redo the masonry, it indicates specific ways to correct defects.

In dry, hot and windy weather, the brick before laying "(is strongly moistened with water, and the ceramic brick is immersed in water in order for the mortar to better adhere and harden normally. This is especially important for laying in seismic areas and performed on mortars with cement binders .

Bibliography

1. SNiP 3.03.01 - 87. "Bearing and enclosing structures" Gosstroy of the USSR. - M.: CITP Gosstroy of the USSR, I988. - 192 p.

2. SNiP 12-03-2001 “Labor safety in construction. Part 1. General requirements "/ Gosstroy of Russia-M.:-1999.-49 p.

3. SNiP 12-04-2002 “Labor safety in construction. Part 2. Construction production "/ Gosstroy of Russia-M.: -2002.-28 p.

4. Afanasiev A.A., Danilov N.N., Kopylov V.D. and others "Technology of construction processes" / Textbook for universities. - M.: Higher. school, 2001. - 464 p.

5. Ishchenko I.I. Stone work. Proc. for vocational schools. - M .: Higher. school 1992. - 239 p.: ill.

6. ENiR Uniform norms and prices for construction, installation and repair work:

Sat E1 Intra-construction transport works. Gosstroy of the USSR - M .: Price list, 1987 - 40s.

Sat E3 Stone work. Gosstroy of the USSR - M .: Price list, 1987 - 48s.

Sat E4 Installation of prefabricated and installation of monolithic reinforced concrete structures. Issue 1 Buildings and industrial facilities. Gosstroy of the USSR - M .: Stroyizdat, 1987 - 64s.

Sat E11 Insulation work. Gosstroy of the USSR - M .: Price list, 1988 - 64 p.

7. Serov K.A. Construction of a multi-storey brick house: met. directions to follow term paper students of specialty 270102 "Industrial and civil construction". - N. Novgorod. Nizhny Novgorod. state architect.-builds. un-t, 2008 - 43 p.

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1.1 Laying foundations

1.2 Brick walls

1.4 Acceptance of masonry work

1. Quality control of stone work

1.1 Laying foundations

The foundations of residential buildings are made of rubble stone, rubble concrete, brick and other stones, and more recently, as a rule, from large concrete and reinforced concrete blocks.

Table 1

For laying foundations and plinths made of hewn and artificial stones, it is recommended to use limestone and concrete stones made on clinker binders. The use of stones made with air binders (for example, gypsum) is not allowed. As aggregates for the manufacture of concrete stones, gravel and crushed stone of natural rocks, crushed stone of strong and stable blast-furnace slags, as well as brick and ceramic crushed stone are used. For laying foundations and plinths of buildings, ordinary clay bricks can also be used, and for plinths of buildings above the waterproofing layer, hollow clay bricks of plastic pressing can be used.

1.2 Brick walls

They begin laying walls only after the foreman or foreman checks: performance of work on laying water supply, heating, gas pipelines and sewer outlets; installation of ceilings over the basement, backfilling of the sinuses of the pit and the installation of blind areas and gutters. To divert surface water from the building; the quality of the wall material brought to the construction site and the readiness of the work front.

Brickwork of walls and pillars is carried out in horizontal rows, observing the verticality of the surfaces. The masonry of walls is carried out according to a multi-row or single-row (chain) system of dressing the seams, the laying of pillars and narrow piers with a width of not more than 1 m is performed according to a three-row system. The master must ensure that the masons use fixtures and tools that ensure the correct laying.

In order to maintain the exact direction of the masonry during the construction of the wall, the same thickness of the rows and the correctness of the masonry in rows, they establish (by plumb and level or by level) orders and pull the mooring cord along them. It is recommended to use inventory metal orders. A mooring made of a twisted cord 2-3 mm thick is strengthened with a bracket.

The quality of the brickwork being performed must be systematically monitored, for which the bricklayer must use a control and measuring tool. The corners of the building are checked with a wooden square, the horizontality of the rows of brickwork of the wall is checked by the rule and the level at least twice on each tier of the masonry. To do this, the rule is placed on the masonry, a level is placed on it and, having aligned it along the horizon, the deviation of the masonry from the horizontal is determined. If it does not exceed the established tolerance, the deviation is eliminated during the laying of subsequent rows.

The verticality of the surfaces of the walls and the corners of the masonry is controlled by the level and plumb line at least twice on each tier of the masonry. If deviations are found that do not exceed the permissible ones, then they are corrected when laying the next tier or floor. Deviations of the axes of structures, if they do not exceed the tolerances established by SNiP 3.03.01-87, are eliminated in the levels of interfloor ceilings.

Brickwork of walls, piers and pillars should begin and end with bonded rows. Bonded rows should be laid under beams, purlins, mauerlats, at the level of wall and pillar cutoffs, as well as in protruding masonry rows (for example, cornices, corbels). Bonded rows are laid out from a whole brick.

The most loaded in the building structure are pillars and piers with a width of less than 2.5 bricks, and therefore they should be laid out from selected whole bricks. Brick-ladder and brick-work can only be used in laying backfill and lightly loaded structures (on sections of walls under windows, when filling frame walls).

The manufacturer of works or the master is obliged to ensure that the height of the facing ceramic bricks corresponds to the height of the masonry material. In exceptional cases, when laying from ordinary single-row bricks, facing stones 140 mm high are used. This combination is permissible only on condition that red brick of plastic pressing is used as the main masonry material with a decrease in the bearing capacity of the masonry when calculated by 10%. This should be mentioned in the project. It is not recommended to use silicate brick with dry-pressed brick.

Wall laying at intersections, junctions or junctions should be done simultaneously, observing the correct dressing of the seams. In cases where brickwork is carried out with breaks, the foreman or foreman must control the correctness of the installation of inclined or vertical gates and check for the presence of steel ties in the previously completed brickwork. Steel ties are located at least 2 m in height and always at the level of each floor. Ties usually have a length of at least 1 m from the junction angle and end with anchors.

It is necessary to periodically (twice per shift) check the thickness of the joints, for which five or six rows of brickwork are measured and the average thickness of the joint is calculated. For example, five rows of wall masonry are 395 mm, then the average height of one row of masonry will be 395:5 = 79 mm, and the average joint thickness will be 790:65 = 14 mm.

The average thickness of the horizontal joints of brickwork within the height of the floor should be 12 mm, vertical - 10 mm. In this case, the thickness of individual horizontal joints must be at least 10 and not more than 15 mm, and vertical - not less than 8 and not more than 15 mm. Thickening of seams against those stipulated by the rules can be allowed only in cases stipulated by the project; in this case, the dimensions of the thickened seams are indicated in the working drawings.

The correctness of filling the joints with mortar is checked by removing individual bricks of the laid out row in different places at least three times along the height of the floor.

When checking the horizontal and transverse vertical seams of the brickwork of walls, as well as the longitudinal seams of the brickwork of lintels and piers with a width of less than 1 m, it is necessary to ensure that they are completely filled with mortar. In the longitudinal seams of blind walls and piers with a width of 1 m or more, partial filling of the seams with mortar is allowed. In the pillars, all seams must be completely filled with mortar, which is checked by removing individual bricks of the laid row in different places (at least three times along the height of the floor). The depth of the joints not filled with mortar from the side of the front surface when laying hollow is allowed no more than 15 mm in the walls and no more than 10 mm (only vertical joints) in the pillars.

The maximum height of walls erected without reinforcement by ceilings or coatings should not exceed the values established by SNiP 3.03.01-87.

In the production of brickwork in seismic areas, increased requirements should be placed on the quality of the used wall stone materials and mortar. Stone, brick or block surfaces must be free of dust before laying. Portland cement should be used as a binder in masonry mortars.

Prior to the start of stone work, the construction laboratory determines the optimal ratio between the pre-wetting value of the local wall stone material and the water content of the mortar mixture. Solutions are used with high water-retaining capacity (water separation is not more than 2%). The use of cement mortars without plasticizers is not allowed.

Masonry of bricks and ceramic slotted stones is carried out in compliance with the following additional requirements: masonry of stone structures is erected for the entire thickness of the structures in each row; horizontal, vertical, transverse and longitudinal joints of the masonry are completely filled with mortar with trimming of the mortar on the outer sides of the masonry; masonry walls in places of mutual adjacency are erected simultaneously; bonded rows of masonry, including backfilling, are laid out from whole stone and brick; temporary (assembly) gaps in the masonry being erected end with an inclined shtraba and are located outside the places of constructive reinforcement of the walls.

When reinforcing brickwork (pillars), it is necessary to ensure that the thickness of the joints in which the reinforcement is located exceeds the diameter of the reinforcement by at least 4 mm, while observing the average joint thickness for this masonry. The diameter of the wire of transverse meshes for reinforcing masonry is allowed not less than 3 and not more than 8 mm. With a wire diameter of more than 5 mm, a zigzag mesh should be used. The use of individual rods (laid mutually perpendicular in adjacent seams) instead of bound or welded rectangular meshes or zigzag meshes is prohibited.

To control the laying of reinforcement during mesh reinforcement of pillars and piers, the ends of individual rods (at least two) in each mesh should be released from the horizontal joints of the masonry by 2-3 mm.

During the masonry process, the worker or foreman must ensure that the methods of fixing the girders, beams, decks and floor panels in the walls and on the pillars are consistent with the project. The ends of the split girders and beams resting on the internal walls and pillars must be connected and embedded in the masonry; according to the project, reinforced concrete or metal linings are laid under the ends of the runs and beams.

When laying ordinary or wedge-shaped lintels, only selective whole bricks should be used and mortar grade 25 and higher should be used. Lintels are embedded in the walls at a distance of at least 25 cm from the slope of the opening. Under the bottom row of bricks, stacked iron or steel wire with a diameter of 4-6 mm is laid in a layer of mortar at the rate of one rod with a cross section of 0.2 cm2 for each part of the lintel half a brick thick, unless the project provides for stronger reinforcement.

When laying the cornice, the overhang of each row should not exceed 1/3 of the length of the brick, and the total extension of the cornice should not exceed half the thickness of the wall. Eaves with a large extension should be reinforced or run on reinforced concrete slabs, etc., reinforcing them with anchors embedded in the masonry.

Brickwork of walls must be carried out in accordance with the requirements of SNiP 3.03.01-87. During the production of brickwork, acceptance is carried out according to the act of hidden work. Hidden works subject to acceptance include: completed waterproofing; installed fittings; masonry areas in the places where girders and beams are supported; the installation of embedded parts - ties, anchors, etc.; fixing cornices and balconies; corrosion protection of steel elements and parts embedded in masonry; sealing the ends of girders and beams in walls and pillars (presence of base plates, anchors and other necessary details); sedimentary seams; support of floor slabs on walls, etc.

1.3 Supervision of stone work in winter

The main method of producing brickwork in winter conditions is freezing. Laying in this way is carried out in the open air using cold bricks and heated mortar, while freezing of the mortar is allowed some time after it has been compressed with a brick.

Electrical heating of winter masonry has not found distribution. Masonry in greenhouses is used as an exception in the construction of foundations or basement walls from rubble concrete. Masonry with the use of fast-hardening mortars prepared on a mixture of Portland cement with aluminous cement is rarely used in construction practice due to the scarcity of aluminous cement. Solutions with additions of sodium chloride or calcium are not used for laying the walls of residential buildings, as they cause increased humidity in buildings. Currently, chemical additives are used for building mortars - sodium nitrite, potash and complex chemical additives - calcium nitrite with urea (NKM - finished product), etc. In this case, the brand of the solution is assigned 50 and higher.

When controlling the construction of masonry by the method of freezing, it should be taken into account that early freezing of mortars in the joints leads to a change in the properties of brickwork compared to masonry walls in the summer. The strength and stability of winter masonry during the thawing period are sharply reduced. The foreman of the masons must ensure that the brick is cleared of snow and ice before laying. For masonry, cement, cement-lime or cement-clay mortars are used. The brand of solutions must be assigned in accordance with the recommendations of the project, as well as taking into account the outside temperature: at an average daily air temperature of up to -3 ° C - a solution of the same brand as for summer masonry; at temperatures from -4 to -20 ° C - the grade of the solution increases by one; at temperatures below -20 ° C - two.

During brickwork by freezing, the temperature of the mortar when it is used depends on the outside temperature, as shown in Table. 2.

table 2

Solutions should be prepared on insulated mortar units using hot water (up to 80°C) and heated sand (not higher than 60°C). To reduce the freezing point of the solution, it is recommended to introduce sodium nitrite in the amount of 5% by weight of mixing water into its composition.

At the workplace, the solution should be stored in insulated boxes with lids, and when the air temperature is below -10 ° C, it should be heated through the bottom and walls of the consumable boxes using tubular electric heaters. It is forbidden to warm a seized or frozen solution with hot water and put it into action.

When laying by pressing, it is recommended to spread the mortar for no more than every two verst bricks or for 6-8 bricks for backfilling. The thickness of the horizontal joints is no more than 12 mm, since with a greater thickness, strong settlement of the walls during the spring thaw is possible. Laying is carried out in full horizontal rows, i.e. without prior laying of the outer verst, to a height of several rows.

The speed of laying bricks in winter should be high enough so that the mortar in the underlying layers of masonry is compacted by the overlying rows before freezing. Therefore, more workers should work on each patch than in summer. By the break in work, the vertical seams must be filled with mortar. During breaks, it is recommended to cover the masonry with roofing paper, plywood; when resuming work, the top layer of masonry should be thoroughly cleaned of snow and ice.

Freezing masonry in the spring can give a large and uneven draft, therefore, clearances for settlement of at least 5 mm should be left above the window and door frames installed in the walls. Sedimentary seams must be made at the junction of walls more than 4 m high, erected in winter, to summer masonry walls, to old structures. Lintels above the openings in the walls, as a rule, are made of precast concrete elements. With spans less than 1.5 m, it is allowed to arrange ordinary brick lintels, while the formwork can be removed no earlier than after 15 days. after complete thawing of the masonry.

After the erection of walls and pillars within the floor, the master must ensure that prefabricated floor elements are immediately laid. The ends of the beams and girders, resting on the walls, are fastened with the masonry of the walls after 2-3 m with metal ties fixed in the vertical longitudinal seams of the masonry. The ends of split girders or floor slabs supported by poles or a longitudinal wall are tied with overlays or anchors.

To give the brickwork, erected by freezing, the required stability in the corners of the outer walls and in the places where the inner walls adjoin the outer walls, steel ties are laid. Ties should be brought into each of the adjoining walls by 1-1.5 m and terminated at the ends with anchors. In buildings with a height of 7 or more floors, steel ties are laid at the level of the floors of each floor, in buildings with a lower number of storeys - at the level of the floors of the second, fourth and each overlying floor.

In some cases, the freezing method is combined with heating the erected building by isolating it from the outside air and connecting the heating system or installing special air heaters. As a result of this, the temperature of the internal air rises, the brickwork thaws, the mortar in it hardens, then the masonry dries up and it is possible to start interior finishing work.

At a positive outside temperature, the masonry thaws. During this period, its strength and stability are sharply reduced and the draft increases. The foreman and the foreman must observe the magnitude, direction and degree of uniformity of the masonry settlement. When thawing the masonry, the work foreman must personally check the condition of all stressed sections of the masonry, as well as ensure that previously left nests, strokes and other holes are laid. With the onset of thaws, random loads should be removed from the floors (for example, residues building materials).

During the entire period of thawing, the masonry made by the freezing method must be carefully controlled and measures taken to ensure the stability of the erected structures. If signs of overvoltage are detected (cracks, uneven settlements), measures should be taken immediately to reduce the load. In such cases, as a rule, temporary unloading racks are installed under the ends of the bearing elements (for example, ceilings, lintels). Temporary racks in multi-storey buildings are installed not only in the unloaded span or masonry opening, but also in all underlying floors in order to avoid overloading the latter.

In case of detection of a deviation of the thawing walls and pillars from the vertical or cracks at the junction of the transverse walls to the longitudinal ones, in addition to temporary fastenings, braces and extensions are immediately installed to eliminate the possibility of displacement development. With significant displacements, tension ropes, clamps, struts are installed to bring the displaced elements to the design position. This should be done before the mortar hardens in the joints, usually no later than five days after the start of thawing of the masonry.

To increase the bearing capacity brick walls and ensuring the spatial rigidity of the entire building in the spring, artificial thawing of the masonry is used, which is carried out by heating the building with closed openings in the walls and ceilings, which can be recommended for buildings to be finished before spring warming. In addition, artificial thawing is used for load-bearing brick walls with solid monolithic reinforced concrete floors, based around the perimeter on these walls, and inside - on reinforced concrete or metal columns of constant height. For artificial thawing, portable oil and gas heaters can be used, with the help of which the temperature in the premises is raised to 30-50 ° C and maintained for 3-5 days. Then within 5-10 days. at a temperature of 20-25 ° C and enhanced ventilation, the walls are dried. After that, using a stationary heating system, the walls of the building are dried to a moisture content of the solution of not more than 8%, and only then they begin finishing work. By the end of heating, the strength of the mortar in the masonry must be at least 20% of the branded strength.

During the spring thaw period, the construction laboratory must systematically monitor the increase in the strength of the winter masonry mortar. In accordance with the instructions of the author's supervision, in several places of the brickwork, the laboratory assistant selects samples-plates with a size of at least 50x50 mm from horizontal joints. It is best to take them under window openings; for this, two rows of bricks are removed and, using a special spatula or trowel, the mortar plate is separated from the brick.

The samples, together with the accompanying act, are sent to the construction laboratory for testing. The accompanying act indicates the number of storeys and the structure of the building, the thickness of the walls and the location of the sampling site, as well as the time of work, the date of sampling and the design grade of the solution. Samples of winter frozen solutions intended to determine the strength at the time of thawing are stored at a negative temperature.

Samples-cubes with an edge of 20-40 mm are made from the samples of the solution delivered to the laboratory or, according to the method of engineer Senyuta, plates in the form of a square, the sides of which are approximately 1.5 times greater than the thickness of the plate, equal to the thickness of the seam. To obtain cubes, two plates are glued together with a thin layer of gypsum, which is also used to level the supporting surface of the cube sample when testing mortar from summer masonry joints.

The strength of winter masonry solutions at the time of thawing is determined by a compression test, leveling the surfaces of the plates instead of gypsum dough by rubbing with a carborundum bar, rasp, etc. Testing of samples in this case should be carried out after thawing the solution for 2 hours in the laboratory at a temperature of 18-20°C. The load on the plate is transmitted through a 20-40 mm metal rod installed in the middle. The sides of the base or the diameter of the rod should be approximately equal to the thickness of the plate. Given the deviations in the thickness of the plates, it is recommended to have a set of rods with different cross sections and diameters during testing.

The compressive strength of the mortar is determined by dividing the breaking load index by the cross-sectional area of the rod. From each sample, five samples are tested and the arithmetic mean value is determined, which is considered to be an indicator of the strength of the solution of this sample. To go to the strength of the solution in cubes with an edge of 70.7 mm, the test results for the plates are multiplied by a factor of 0.7.

The test results of cube samples with an edge of 30-40 mm, glued from plates and leveled with a gypsum layer 1-2 mm thick, are multiplied by a factor of 0.65, and the test results of plates also leveled with gypsum are multiplied by a factor of 0.4. For summer masonry, these coefficients are taken equal to 0.8 and 0.5, respectively. To test the strength of mortar samples, lever devices are used that fix the strength with an error of up to 0.2 MPa, as well as RMP-500 and RM-50 tensile machines with reversers. These mortar tests help to develop the necessary measures in time to ensure the stability of the brickwork during the period of complete thawing.

1.4 Acceptance of masonry work

In the process of acceptance of stone structures, the volume and quality of work performed, the compliance of structural elements with working drawings and the requirements of SNiP 3.03.01-87 are established.

Throughout the duration of the work, representatives construction organization and technical supervision of the customer carry out the acceptance of hidden work and draw up the relevant acts.

When accepting stone structures, the quality of materials used, semi-finished products and factory-made products is established according to passports, and the quality of mortars and concretes prepared at construction is determined according to laboratory tests. In cases where the applied stone materials were subjected to a control check in a construction laboratory, the results of these laboratory tests must be submitted for acceptance.

During the acceptance of finished stone structures, the following are checked:

Correctness of transportation, thickness and filling of seams;

Verticality, horizontality and straightness of masonry surfaces and corners;

Correctness of the device of sedimentary and temperature seams;

Correct arrangement of smoke and ventilation ducts;

Availability and correct installation of embedded parts;

The quality of the surfaces of facade non-plastered brick walls (evenness of color, observance of dressing, pattern and jointing);

The quality of facade surfaces lined with various kinds of slabs and stones;

Ensuring the removal of surface water from the building and protection of foundations and basement walls from them.

Controlling the quality of stone structures, they carefully measure deviations in the size and position of structures from the design ones and make sure that the actual deviations do not exceed the values \u200b\u200bspecified in SNiP 3.03.01-87 .. Permissible deviations are given in table. 3.

Acceptance of arches, vaults, retaining walls and other especially critical stone structures is drawn up in separate acts. If, during the production of stone work, reinforcement of individual structures was performed, then upon acceptance, working drawings of the reinforcement and a special act for the work performed to strengthen the stone structures are presented. When accepting stone structures made in winter, a winter work log and acts for hidden work are presented.

stone foundation brick construction

Table 3 Permissible deviations in the dimensions and positions of structures made of bricks, ceramic and natural stones of the correct form, from large blocks

Tolerances			Foundations
Deviations from design dimensions:
by thickness
by marks of cutoffs and floors
according to the width of the piers
by the width of the openings
by offset of the axes of adjacent window openings
by displacement of the axes of structures
Deviations of masonry surfaces and angles from the vertical:
one floor
for the whole building
Deviations of masonry rows from the horizontal per 10 m of wall length
Irregularities on the vertical surface of the masonry, detected when applying a 2 m long lath