Installation work in the construction of concrete structures. Processes of installation of reinforced concrete structures. Installation of floor slabs

3.1. Preliminary storage of structures in on-site warehouses is allowed only with appropriate justification. The on-site warehouse should be located in the area of ​​the assembly crane.

3.2. The installation of the structures of each overlying floor (tier) of a multi-storey building should be carried out after the design fixing of all installation elements and the concrete (mortar) of the monolithic joints of the supporting structures of the strength specified in the PPR.

3.3. In cases where the strength and stability of structures during the assembly process are provided by welding field connections, it is allowed, with the appropriate indication in the project, to mount structures of several floors (tiers) of buildings without monolithic joints. At the same time, the project should provide the necessary instructions on the order of installation of structures, welding of joints and monolithic joints.

3.4. In cases where permanent connections do not ensure the stability of structures during their assembly, it is necessary to use temporary mounting connections. The design and number of connections, as well as the procedure for their installation and removal, should be indicated in the PPR.

3.5. Brands of solutions used in the installation of structures for bedding should be indicated in the project. The mobility of the solution should be 5-7 cm along the immersion depth of a standard cone, except for cases specifically stipulated in the project.

3.6. The use of a solution whose setting process has already begun, as well as the restoration of its plasticity by adding water, are not allowed.

3.7. Limit deviations from the alignment of landmarks when installing prefabricated elements, as well as deviations of completed mounting structures from the design position, should not exceed the values ​​\u200b\u200bgiven in Table. 12.

Table 12

The designation adopted in Table. 12: n - the serial number of the tier of columns or the number of panels installed in height.

Note. Support depth horizontal elements on load-bearing structures should not be less than that specified in the project.

INSTALLATION OF FOUNDATION BLOCKS AND WALLS OF THE UNDERGROUND PART OF BUILDINGS

3.8. The installation of glass-type foundation blocks and their elements in the plan should be carried out relative to the alignment axes in two mutually perpendicular directions, combining the axial risks of the foundations with the landmarks fixed on the base, or controlling the correct installation with geodetic instruments.

3.9. Block installation strip foundations and basement walls should be made, starting with the installation of lighthouse blocks in the corners of the building and at the intersection of the axes. Beacon blocks are installed, combining their axial risks with the risks of the center axes, in two mutually perpendicular directions. The installation of ordinary blocks should be started after reconciling the position of the lighthouse blocks in terms of and in height.

3.10. Foundation blocks should be installed on a layer of sand leveled to the design mark. Limit deviation the marks of the leveling layer of sand from the design level should not exceed minus 15 mm.

Installation of foundation blocks on bases covered with water or snow is not allowed.

Foundation glasses and supporting surfaces must be protected from contamination.

3.11. The installation of basement wall blocks should be carried out in compliance with the dressing. Ordinary blocks should be 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 ground level must be aligned with inside walls, and above - on the outside. Vertical and horizontal seams between blocks must be filled with mortar and embroidered on both sides.

INSTALLATION OF COLUMNS AND FRAMES

3.12. The design position of columns and frames should be verified in two mutually perpendicular directions.

3.13. The bottom of the columns should be aligned, combining the risks that indicate their geometric axes in the lower section, with the risks of the center axes or geometric axes of the columns below.

The method of supporting the columns on the bottom of the glass should ensure that the bottom of the column is secured from horizontal movement for a period until the node is monolithic.

3.14. The top of the columns of multi-storey buildings should be aligned, combining the geometric axes of the columns in the upper section with the risks of the center axes, and the columns of one-story buildings - by combining the geometric axes of the columns in the upper section with the geometric axes in the lower section.

3.15. The alignment of the bottom of the frames in the longitudinal and transverse directions should be carried out by combining the marks of the geometric axes with the marks of the center axes or the axes of the racks in the upper section of the underlying frame.

Alignment of the top of the frames should be carried out: from the plane of the frames - by combining the notches of the axes of the frame racks in the upper section relative to the center axes, in the plane of the frames - by observing the marks of the supporting surfaces of the racks of the frames.

3.16. The use of gaskets not provided for by the project at the joints of columns and frame racks for leveling elevations and bringing them to a vertical position without agreement with the design organization is not allowed.

3.17. Landmarks for aligning the top and bottom of columns and frames should be indicated in the PPR.

INSTALLATION OF BARS, BEAMS, TRUMS, FLOOR SLABS AND COVERINGS

3.18. The laying of the elements in the direction of the span to be covered must be carried out in compliance with the dimensions of the depth of support established by the project. support structures or gaps between mating elements.

3.19. Installation of elements in the transverse direction of the overlapped span should be carried out:

crossbars and inter-column (tie) plates - combining the risks of the longitudinal axes of the installed elements with the risks of the axes of the columns on the supports;

crane beams - combining the risks that fix the geometric axes of the upper chords of the beams with the center axis;

truss and truss trusses (beams) when supported on columns, as well as truss trusses when supported on truss trusses - combining the risks that fix the geometric axes of the lower chords of the trusses (beams) with the risks of the axes of the columns in the upper section or with the reference risks in the supporting node of the truss farms;

truss trusses (beams) resting on the walls - combining the risks that fix the geometric axes of the lower chords of the trusses (beams) with the risks of the center axes on the supports.

In all cases, roof trusses (beams) should be installed in compliance with the one-sided direction of deviations from the straightness of their upper chords:

floor slabs - according to the markup that determines their design position on the supports and is carried out after the structures on which they rest (beams, crossbars, trusses, etc.) are installed in the design position;

roofing slabs along trusses (rafter beams) - symmetrically with respect to the centers of truss nodes (embedded products) along their upper chords.

3.20. Crossbars, intercolumn (coupled) slabs, trusses (truss beams), roofing slabs along trusses (beams) are laid dry on the supporting surfaces of load-bearing structures.

3.21. Floor slabs must be laid on a layer of mortar with a thickness of not more than 20 mm, combining the surfaces of adjacent slabs along the seam from the side of the ceiling.

3.22. The use of pads not provided for by the project to align the position of the stacked elements according to the marks without agreement with the design organization is not allowed.

3.23. Alignment of crane beams in height should be carried out according to the highest mark in the span or on the support using gaskets made of steel sheet. In the case of using a package of gaskets, they must be welded together, the package is welded to the base plate.

3.24. The installation of trusses and rafter beams in a vertical plane should be carried out by aligning their geometric axes on the supports relative to the vertical.

WALL PANELS INSTALLATION

3.25. Installation of panels of external and internal walls should be carried out, resting them on beacons adjusted relative to the installation horizon. The strength of the material from which the beacons are made should not be higher than the compressive strength of the solution used for the bedding, established by the project.

Deviations of marks of beacons relative to the mounting horizon should not exceed ± 5 mm. In the absence of special instructions in the project, the thickness of the beacons should be 10-30 mm. There should be no gaps between the end of the panel after it has been aligned and the mortar bed.

3.26. Alignment of panels of external walls of single-row cutting should be carried out:

in the plane of the wall - combining the axial risk of the panel at the bottom level with the orientation risk on the floor, taken out from the center axis. If there are zones of compensation of accumulated errors in the joints of the panels (when panels are overlapped in the places where loggias, bay windows and other protruding or sinking parts of the building are installed), alignment can be performed using templates that fix the design size of the seam between the panels;

from the plane of the wall - combining the lower edge of the panel with the installation risks on the floor, taken out from the center axes;

in the vertical plane - aligning the inner edge of the panel with respect to the vertical.

3.27. The installation of belt panels of the outer walls of frame buildings should be carried out:

in the plane of the wall - symmetrically with respect to the axis of the span between the columns by aligning the distances between the ends of the panel and the risks of the axes of the columns at the installation level of the panel;

from the plane of the wall: at the level of the bottom of the panel - by aligning the lower inner edge of the installed panel with the edge of the underlying panel; at the top level of the panel - by combining (using a template) the edge of the panel with the line of the axis or the edge of the column;

3.28. The alignment of the wall panels of the outer walls of frame buildings should be carried out:

in the plane of the wall - combining the risk of the axis of the bottom of the panel being installed with the reference risk marked on the waist panel;

from the plane of the wall - aligning the inner edge of the installed panel with the edge of the underlying panel;

in the vertical plane - by aligning the inner and end faces of the panel relative to the vertical.

INSTALLATION OF VENTILATION UNITS, VOLUME UNITS OF ELEVATOR SHAFT AND SANITATION CABINS

3.29. When installing ventilation units, it is necessary to monitor the alignment of the channels and the thoroughness of filling the horizontal joints with mortar. Alignment of ventilation units should be carried out by aligning the axes of two mutually perpendicular faces of the units to be installed at the level of the lower section with the marks of the axes of the lower unit. Relative to the vertical plane, the blocks should be installed by aligning the planes of two mutually perpendicular faces. joints ventilation ducts blocks should be thoroughly cleaned of the solution and prevent it and other foreign objects into the channels.

3.30. Volume blocks elevator shafts should be mounted, as a rule, with brackets installed in them for fixing guide cabins and counterweights. The bottom of the volumetric blocks must be installed according to the reference risks placed on the ceiling from the center lines and corresponding to the design position of two mutually perpendicular walls of the block (the front and one of the side walls). Relative to the vertical plane, the blocks should be installed by aligning the faces of two mutually perpendicular walls of the block.

3.31. Sanitary cabins should be installed on gaskets. The alignment of the bottom and verticality of the cabins should be carried out according to clause 3.30. When installing the cabins, the sewer and water risers must be carefully aligned with the corresponding risers of the cabins below. Openings in the floor panels for passing the risers of the cabins after installing the cabins, mounting the risers and carrying out hydraulic tests must be carefully sealed with mortar.

CONSTRUCTION OF BUILDINGS BY THE METHOD OF LIFTING FLOORS

3.32. Before lifting the floor slabs, it is necessary to check the presence of design gaps between the columns and collars of the slabs, between the slabs and the walls of the stiffening cores, as well as the cleanliness of the holes provided for by the project for lifting rods.

3.33. Floor slabs should be lifted after the concrete reaches the strength specified in the project.

3.34. The equipment used must ensure uniform lifting of floor slabs relative to all columns and stiffeners. The deviation of the marks of individual reference points on the columns during the lifting process should not exceed 0.003 span and should not exceed 20 mm, unless other values ​​are provided for in the project.

3.35. Temporary fastening of slabs to columns and stiffeners should be checked at each stage of lifting.

3.36. Structures raised to the design mark should be fixed with permanent fasteners; at the same time, acts of intermediate acceptance of structures completed by installation should be drawn up.

WELDING AND ANTI-CORROSION COATING OF EMBEDDED AND CONNECTING PRODUCTS

3.37. Welding of embedded and connecting products must be carried out in accordance with Sec. eight.

3.38. Anti-corrosion coating of welded joints, as well as areas of embedded parts and connections, must be carried out in all places where the factory coating is violated during installation and welding. The method of anti-corrosion protection and the thickness of the applied layer must be specified in the project.

3.39. Immediately before applying anticorrosion coatings, the protected surfaces of embedded products, ties and welded joints must be cleaned of welding slag residues, metal spatter, grease and other contaminants.

3.40. In the process of applying anti-corrosion coatings, it is necessary to ensure that the corners and sharp edges of the products are covered with a protective layer.

3.41. The quality of anti-corrosion coatings should be checked in accordance with the requirements of SNiP 3.04.03-85.

3.42. Data on the performed anti-corrosion protection of joints must be documented in certificates of examination of hidden works.

MONOLICHING JOINTS AND SEAMS

3.43. Sealing of joints should be carried out after checking the correct installation of structures, accepting the connections of elements in the junctions and performing anti-corrosion coating welded joints and damaged areas of coating of embedded products.

3.44. The class of concrete and the brand of mortar for embedding joints and seams must be indicated in the project.

3.45. Concrete mixtures used for sealing joints must meet the requirements of GOST 7473-85.

3.46. For the preparation of concrete mixes, fast-hardening Portland cements or Portland cements M400 and higher should be used. In order to intensify the hardening of the concrete mixture at the joints, it is necessary to apply chemical additives- hardening accelerators. largest size coarse aggregate grains in the concrete mixture should not exceed 1/3 smallest size joint section and 3/4 of the smallest distance in the light between the reinforcement bars. To improve workability in the mixture, plasticizing additives should be introduced in accordance with Sec. 2.

3.47. Formwork for embedding joints and seams, as a rule, must be inventory and meet the requirements of GOST 23478-79.

3.48. Immediately before embedding joints and seams, it is necessary to: check the correctness and reliability of the installation of the formwork used for embedding; clean the mating surfaces from debris and dirt.

3.49. When embedding joints, compaction of concrete (mortar), care for it, control of the holding mode, as well as quality control should be carried out in accordance with the requirements of Sec. 2.

3.50. The strength of concrete or mortar at the joints by the time of stripping must correspond to that specified in the project, and in the absence of such an indication, it must be at least 50% of the design compressive strength.

3.51. The actual strength of the laid concrete (mortar) should be controlled by testing a series of samples made at the place of pouring. To check the strength, at least three samples should be made per group of joints concreted during a given shift.

Samples must be tested in accordance with GOST 10180-78 and GOST 5802-86.

3.52. Methods of preliminary heating of joined surfaces and heating of monolithic joints and seams, duration and temperature and humidity conditions of curing concrete (mortar), methods of insulation, timing and procedure for stripping and loading structures, taking into account the specifics of work in winter conditions, as well as in hot and dry weather, should be indicated in the PPR.

WATER-, AIR- AND HEAT INSULATION OF JOINTS OF EXTERIOR WALLS OF COMPLETE BUILDINGS

3.53. Joint insulation work must be carried out by specially trained workers who have a certificate for the right to carry out such work.

3.54. Materials for insulating joints should be used only from those specified in the project; replacement of materials without agreement with the design organization is not allowed.

3.55. Transportation, storage and use of insulating materials should be carried out in accordance with the requirements of standards or specifications.

Insulating materials after the expiration of the storage period established by the standards or technical conditions before use are subject to a control check in the laboratory.

3.56. Panels must be delivered to objects with primed surfaces forming joints. The primer should form a continuous film.

3.57. The surfaces of the panels of the outer walls, forming joints, before performing work on the installation of water and air insulation, must be cleaned of dust, dirt, concrete sagging and dried.

Surface damage to concrete panels at the joints (cracks, shells, chips) must be repaired using polymer-cement compositions. The disturbed primer layer must be restored in construction conditions.

The application of sealing mastics to wet, frosty or icy joint surfaces is not allowed.

3.58. For air insulation of joints, air-protective tapes are used, fixed on adhesives or self-adhesive. It is necessary to overlap the air-protective tapes along the length with the length of the overlap section of 100-120 mm. The joints of the tapes in the wells of vertical joints should be located at a distance of at least 0.3 m from the intersection of vertical and horizontal joints. In this case, the end of the underlying tape should be glued over the tape installed at the junction of the floor to be installed.

It is not allowed to connect the tapes in height until the wells of the joints of the lower floor are monolithic.

3.59. The glued air barrier tape must adhere tightly to the insulated joint surface without bubbles, swellings and folds.

3.60. Thermal insulation inserts should be installed in the wells of the vertical joints of the panels of the outer walls after the installation of air insulation.

Lining materials must have a moisture content established by the standards or specifications for these materials.

3.61. The installed liners must fit snugly against the surface of the well along the entire height of the joint and be fixed in accordance with the project.

There should be no gaps at the joints of the heat-insulating inserts. When eliminating the gaps between the liners, they must be filled with material of the same bulk density.

3.62. Sealing gaskets in the mouths of joints of closed and drained types should be installed dry (without coating with glue). At the intersections of closed joints, sealing gaskets should first be installed in horizontal joints.

3.63. In closed-type joints when overlapping external wall panels, in horizontal drained-type joints (in the area of ​​the drainage apron), in horizontal joints open type, as well as in the joints of the panels of the tongue-and-groove structure, it is allowed to install sealing gaskets before mounting the panels. In this case, the gaskets must be fixed in the design position. In other cases, the installation of sealing gaskets must be carried out after the installation of the panels.

It is not allowed to nail sealing gaskets to the surfaces forming the butt joints of the outer wall panels.

3.64. Sealing gaskets should be installed in joints without breaks.

It is necessary to connect the sealing gaskets along the length “by the mustache”, placing the junction at a distance of at least 0.3 m from the intersection of the vertical and horizontal joints.

Sealing joints with two gaskets twisted together is not allowed.

3.65. Compression of gaskets installed at the joints should be at least 20% of the diameter (width) of their cross section.

3.66. Isolation of joints with mastics should be carried out after the installation of sealing gaskets by injecting mastics at the mouth of the joint with electric seals, pneumatic, manual syringes and other means.

It is allowed to apply hardening mastics with spatulas when performing repair work. Liquefaction of mastics and their application with brushes is not allowed.

3.67. When preparing two-component hardening mastics, it is not allowed to violate the passport dosage and disassemble their components, mix the components manually and add solvents to them.

3.68. The temperature of the mastics at the time of application at positive outdoor temperatures should be 15-20°C. AT winter periods the temperature at which the mastic is applied, as well as the temperature of the mastic at the time of application, must correspond to those specified in specifications mastic manufacturer. In the absence of relevant instructions in the technical specifications, the temperature of the mastics at the time of application should be: for non-hardening - 35-40 ° C, for hardening - 15-20 ° C.

3.69. The applied layer of mastic should fill without voids the entire mouth of the joint to the elastic gasket, not have gaps, sagging.

The thickness of the applied layer of mastic must correspond to that established by the project. The maximum deviation of the thickness of the mastic layer from the design should not exceed plus 2 mm.

The resistance of the applied mastics to separation from the surface of the panel must comply with the indicators given in the relevant standards or specifications for the mastics.

3.70. Protection of the applied layer non-hardening mastic must be made with the materials specified in the project. In the absence of special instructions in the project, polymer-cement mortars, PVC, styrene-butadiene or coumarone-rubber paints can be used for protection.

3.71. In open joints, rigid water barriers should be inserted into the vertical channels of open joints from top to bottom until they stop against the drainage apron.

When using rigid water baffle screens in the form of corrugated metal tapes they should be installed in vertical joints so that the opening of the extreme corrugations faces the facade. The shield must fit freely into the groove. When opening the vertical joint of panels more than 20 mm, two tapes riveted along the edges should be installed.

Flexible water barriers (tapes) are installed in vertical joints both outside and inside the building.

3.72. Non-metallic drainage aprons made of elastic materials should be glued to the upper edges of the joined panels for a length of at least 100 mm on both sides of the axis of the vertical joint.

3.73. Insulation of joints between window (balcony door) blocks and quarters in the openings of enclosing structures should be carried out by applying non-hardening mastic to the surface of the quarter before installing the block or by injecting mastic into the gap between window blocks and enclosing structures after fixing the block in the design position. The junction of metal window sill drains to the box must also be insulated with non-hardening mastic.

When insulating joints between window blocks and enclosing structures with openings without a quarter, a sealing gasket should be installed before applying the mastics.

3.74. The performance of work on the insulation of joints must be recorded daily in the journal.

For the entire range of works on the joint insulation, certificates of examination of hidden work should be drawn up in accordance with SNiP 3.01.01-85.

The main purpose reinforced concrete structures- to serve as the supporting frame of the building. The longevity and reliability of the structure depends on how correctly and efficiently they are delivered.

The slightest errors in the assembly and installation of this element of the building are fraught with the most serious consequences. Therefore, such work should be carried out by professional and experienced specialists armed necessary equipment. Types and methods of installation of steel and reinforced concrete structures are different, but the ultimate goal is the same - to give the structure maximum stability.

Classification of reinforced concrete structures

Installation of reinforced concrete structures

Installation of metal and reinforced concrete structures depends on the purpose and their design features. According to the criterion of purpose, the structures are divided into:

• Foundations;
• beams;
• Farms;
• columns;
• Plates.

The former serve as a support for the entire building, the rest - as ceilings and load-bearing structures, to support the frame elements and transfer force from one structure to another.

According to the features of manufacturing, the structures are divided into:

• Monolithic;
• prefabricated;
• Prefabricated monolithic.

Monolithic structures are the most durable and reliable. They are used in cases where a large load on load-bearing element. Prefabricated structures are not so strong, too dependent on weather conditions and can be used where special reliability is not required.

But they are easy to install and easy to transport. Prefabricated monolithic structures have enough high strength and according to this indicator they are not much inferior to monolithic ones. Therefore, they are often used in the construction of bridges, in the floors of multi-storey buildings.

Types of work during the installation of structures

Installation of reinforced concrete structures is mainly a matter for professionals

Installation of metal and reinforced concrete structures is divided into the following types of work:

• Foundation installation;
• Installation of the walls of the basement of the building;
• Mounting structural elements building frame;
• Mounting ventilation elements and blocks;
• Installation of internal elements of the building.

Each of these types of work requires compliance with a special technology and the use of those steel and reinforced concrete structures that correspond to the tasks.

Initial construction stage

Before installation, you must preparatory work. Since these structures are of considerable weight, it is necessary to consider the entrance to the construction site of vehicles and special equipment(e.g. cranes).

Further, geodetic work is carried out to tie the axes of the structure to the terrain. It also determines which structures and in what quantity should be used. Surveying the terrain and preliminary calculations allow you to avoid cost overruns and loss of time for reworking incorrectly mounted structures.

After transportation to the assembly site, the structures are laid out in right order. This is a very important and responsible part of the work, because a truss, beam or slab is not a match, it is very difficult to pull it out from under other structures. The basic layout rule: if the structures are stacked on top of each other, the elements that are installed first of all should lie on top, the bottom row or especially heavy structures are laid on wooden substrates, free access of equipment to each structure and the possibility of grabbing the part by the crane boom, as well as convenience should be provided. rafters.

Foundation installation

The laying and installation of reinforced concrete structures in the pit is carried out according to a pre-compiled scheme, in which the location and assembly order of all components are accurately noted. Beacon blocks are initially laid in the pit. This is the name of reinforced concrete structures, which are located at the corners of the foundation and at the intersections of the axes of the structure.

Monolithic strip foundation

Then, pillow blocks are laid, between which technological gaps are left (for example, to pass cables or pipelines). Blocks of strip foundations should be located on a sand bed.

Next, the foundation walls and basement floors are installed. Floor panels are welded to embedded parts in pillow blocks, and the joints between the panels are filled with cement mortar. The installation of reinforced concrete foundation structures requires constant alignment of the position of the walls with a level, both vertically and horizontally.

Upon completion of laying, a mounting horizon is installed - a cement layer along the upper part of the walls to reach the design mark and level the upper edge. After that, the basement is built, and the basement is closed with slabs that form its ceiling and at the same time the floor of the lower floor.

prefabricated reinforced concrete foundations installed in a slightly different order. First, a slab is laid at the bottom of the pit, where a block glass is welded. He is placed on a kind of "bed" consisting of a cement solution. Block foundations are installed by a crane, and their setting in correct position carried out by weight.

Installation of columns

Before installation on columns, risks are applied on four faces above and below, indicating the axes. The columns are laid out in front of the installation site in such a way that the crane makes a minimum of movements, and it is convenient for workers to inspect and fix the structures. The column is installed in a glass, reinforced on the foundation.

• The column is attached to the crane hook in such a way that when it is lifted, it stands upright;
• The crane puts the column in a vertical position. Depending on the weight of the column, different methods of lifting are used - turning, turning with sliding. For slinging columns, friction or pin grips are used;
• Lowering to the foundation and reconciliation of the position. It is impossible to remove the column from the crane until its correct position is unambiguously determined using a level and theodolite.

The column should stand strictly vertically without the slightest inclination. Temporary fastening of the column for its adjustment is carried out using wedge liners.

The next step is to fix the column in the foundation glass. It is produced by injection into the joints of the column concrete mortar(usually a blower). After reaching 50% of the design strength of concrete, the wedge inserts can be removed. Further work associated with the load on the column, as well as the laying of beams, are carried out only after the mixture has completely hardened.

Installation of beams and roof trusses

Reinforced concrete structures

Beams and roof trusses are installed either simultaneously with the roof slabs or separately. Installation of metal and reinforced concrete structures of the main part of the building is carried out depending on the design requirements.

Before installing the trusses, all supporting platforms are verified and cleaned and the risks of the axes are applied. After that, the structures are delivered to the installation site, slinging and lifting is carried out. When installed on a support, the truss or beam is temporarily fixed with spacers made of metal pipes, which are attached before the start of the ascent.

After that, the truss is adjusted and checked for stability and correct installation according to the risks. The truss or beam must stand in such a way that it does not violate the geometry of the building and does not move relative to the axes of the frame.

Only after a complete check is the final fixing of the element. Embedded parts are welded to base plate or column head, as well as to previously installed trusses. Washers should also be welded anchor bolts. Only after the beams and trusses are fully installed can they be unstrapped.

After the frame is erected, a horizontal stiffening belt is installed, which is a monolithic reinforced concrete beam passing along the upper ends of the bearing walls. Its task is to ensure the horizontal rigidity of the structure.

Mounting plates

Like any installation of reinforced concrete structures, the installation of slabs requires pre-training. On span trusses, scaffolds or fences must be installed. There are two main ways of mounting plates - longitudinal and transverse. In the first case, the crane moves along the span, in the second - across the span. Coating slabs are stacked between columns for delivery to the coating site.

building a house

The first slab is placed in a place previously marked on the farm, the rest - right next to it. If the building is framed, the floor slabs are laid after the installation of crossbars, purlins and spacer plates, and if it is frameless, after the walls have been built. When laying the slab on the surface, a "bed" is arranged from the solution. Excess solution is squeezed out by the plate itself. The first plate must be welded to the truss at four nodes, the next - at three. Inter-butt joints are sealed with a solution of cement and sand.

Installation of wall panels

Wall panels are installed after the construction of the building frame and the laying of floors. Before lifting, the panels are grouped into cassettes. With this method of storage, the installation of metal and reinforced concrete structures intended for the construction of walls is the most rational. Cassettes can be located between the wall and the faucet, behind the faucet, as well as in front of it.

Panels are installed by installers only from the inside of the building. Wall panels are placed along the entire height of the building with a section between two columns. Therefore, in one cassette there should be such a number of panels to cover the entire area along its entire height.

The panel is accepted by installers at the junction of this structure with the column. To do this, it is necessary to provide workers with access to these points in advance. If there is no transverse overlap, you will have to install cradles, scaffolds or a lift.

The installation of the first row of panels is of particular importance, therefore their position and compliance with the applied risks is checked especially carefully. External panels perform not only supporting and protective, but also aesthetic functions. Therefore, the seams between the panels must be sealed not only carefully, but very carefully and not exceed the established norms.

Internal wall panels are placed before the installation of the ceilings of the upper floor. The panels are attached to the columns with clamps, to the floor slabs - with struts. The final fixing of the wall panels is carried out by welding them with the elements of the building frame.

The main material of the construction industry is concrete. From it, structures and their elements of various types and purposes are produced in the factory, at landfills, directly at construction sites, which form the supporting structure and appearance of structures. Regulations establish practical requirements to the process of installation of concrete and reinforced concrete products.

What are reinforced concrete structures?

Products are divided into prefabricated, monolithic, prefabricated-monolithic. The first are factory samples that are combined into a frame or connected to it by welding and subsequent concreting. The second ones are cast on objects, the frames of which will take increased loads (foundation slabs, self-supporting frames, etc.).

The latter - in a rational way combine heterogeneous elements of the first and second types. Factory designs are equipped with conventional and (increases resistance to bending loads). Monolithic products contain only a conventional reinforcing cage.

SNiP 3.03.01-87, which establishes standards for all stages of installation of reinforced concrete structures, technologies and materials. GOST 10922-90, establishing general terms and Conditions formation of products from reinforcement and their welding in reinforced concrete structures. GOST 14098-91, which standardizes types of structural design, geometric parameters of joints when welding embedded parts and fittings. The requirements of the listed documents are included in the project for the production of work at construction sites (PPR).

How are structures installed?

Installation of prefabricated concrete and reinforced concrete structures includes:

• intermediate storage and movement of products;
• installation of reinforced concrete products from prefabricated elements;
• reinforcement in monolithic structures;
• pouring and care of concrete to curing;
• concrete processing.

Warehousing and moving

Placement of products on the construction site is carried out taking into account the sequence of mounting. Products are stacked (admissible amount individually for a specific type) on spacers about 3 cm high, located strictly one under the other, or in group cassettes. The frame components are placed in the installation area (operating radius of the crane reach without changing the reach of its boom) of the crane. Changing the reach of the boom is allowed only for the transfer of floor slabs. The movement of structural components is carried out only by lifting equipment.

The slings are attached to the mounting fittings in accordance with the drawings. Manual transfer of loads weighing up to 50 kg is allowed (drag - prohibited) at a distance of up to 30 m. Before assembly, it is allowed to lay out the same type components (columns, beams, etc.) on gaskets in order to inspect the condition of the reinforcement outlets. Such structural releases are protected from damage; it is unacceptable to attach slings to them.

Raising and lowering loads is carried out with a static hover above the break-off / installation point at a height of 300 mm. The spatial position of the products in this case must correspond to the design position when installed in the building structure (examples - panels, columns, flights of stairs etc.). To improve orientation in the air, one or two guys attached to them are used. Hardware at the construction site is placed sorted in a special room.

Concrete works

The components of concrete compositions are dosed by weight. The volume of water in the solution is a guideline for the volume of modifying additives that change the properties of concrete (frost resistance, plasticity, fluidity, hydrophobicity, etc.). The proportions of the components are determined with respect to all batches (grades) of cement and aggregates by and . It is not allowed to increase the workability of concrete by adding water to the mixed mix. The requirements established by SNiP 3.03.01-87 for the formation of solutions are shown in Table 1.

Places of laying (forms), their seams and surfaces are cleaned from seasonal sedimentary moisture, dirt, debris, oil and grease stains, cement dust film, then washed under pressure and dried. The size of aggregate grain fractions should not exceed 1/3 of the size of the weld section at the narrowest point, should not exceed 3/4 of the minimum distance between the reinforcing bars. The concrete is poured in layers. Vibrotamper is performed by immersing the tool to a depth of 50 - 100 mm.

Its support on embedded parts, formwork and reinforcement is unacceptable. The step of movement on the surface is 1.5 of the range of the equipment. Surface action models are rearranged with 100 mm overlap of compaction areas. Subsequent layers of the solution are poured after the strength of the previous layer is 1.5 MPa.

Concrete processing

After taking shelter cement screed 20 - 30 mm high, which is covered with a waterproofing compound. subjected to the formation of technological holes and openings, anti expansion joints(a set of strength indicators from 50% and above). It is preferable to use diamond cutting tools(exclude vibration loads) with forced heat removal from the working area.

Reinforcement

It is carried out by installing factory-made flat reinforcing meshes with longitudinal and transverse components in the formwork. Such reinforcement groups long rods and keeps transverse rods from deforming. Volumetric connection of layers of structural reinforcement inside the formwork and working reinforcement different products is carried out by knitting wire, welding, screw couplings, crimp sleeves, etc. Before pouring, the quality of mounting the metal is checked, the mold is freed from debris, scale.

The reinforcing structure should be 20-30 mm high on all sides. The pouring of the solution is accompanied by sealing with a bayonet and a vibrotamper. (the ratio of the sum of the cross-sectional areas of the reinforcing metal to the cross-sectional area of ​​\u200b\u200bthe structure) of the lower columns of the building is set at least 2.01%, the upper ones - 0.79%. concrete structure metal can fill no more than 0.1%.

The topic of this article is reinforced concrete load-bearing and enclosing structures. We have to deal with their classifications and get acquainted with the requirements for installation work set out in the current regulatory documents.

Construction industrial building. Floor slabs - reinforced concrete, load-bearing frame - steel.

Classification

What types of reinforced concrete structures are used in construction?

• Monolithic. The most obvious example is modern frame-monolithic apartment buildings. The load-bearing frame of the building is cast on site in a removable formwork; after the concrete has gained strength, enclosing walls and partitions are erected from light porous materials.
• prefabricated. An example of such a design is panel house: it is built from finished elements. The installation of precast concrete structures, as a rule, comes down to combining the frame reinforcing the structural elements by welding and concreting the joints.

Useful: this technology, among other things, allows the use of structural elements with prestressed reinforcement.
The reinforcing rods heated by high currents, cooling down, stretch and thereby increase the bending strength of the product.
The method of producing reinforced concrete with reinforcement tension implies industrial conditions.

• Prefabricated - monolithic. This type of structure includes, for example, a ceiling made of slabs laid on monolithic crossbars.

Typical combined design. 1 - monolithic columns; 2 - floor slabs; 3 - monolithic crossbars; 4 - external walls of aerated concrete blocks.

In addition, during the construction of buildings and industrial facilities, dissimilar elements can be combined into a single structure. The joint installation of reinforced concrete and steel structures is used, for example, when creating open warehouses adjacent to a building: beams or canopy trusses are welded to embedded parts in concrete or anchored to a monolith.

Regulations

What documents regulate the installation of reinforced concrete products?

We will have to familiarize ourselves mainly with the content of the last document: it contains the most full information for installation work.

SNiP 3.03.01-87

The document applies to the following list of works:

• Erection of monolithic concrete and reinforced concrete walls, beams, columns, ceilings and other load-bearing and enclosing structures.

Monolithic housing construction is one of the special cases of SNiP application.

• Installation of reinforced concrete and metal structures prefabricated type in the conditions of a construction site.
• Welding of mounting joints of metal structures, welding of reinforcement joints of reinforced concrete products and embedded parts in them.
• Construction of stone, ceramic, silicate and concrete blocks.

The work begins with the preparation of a PPR (project for the production of works). The project, among other things, should include a statement of the order of the main operations, taking into account the safety and manufacturability of construction.

All materials used must comply with applicable standards and/or specifications.

Let's study the basic requirements of SNiP.

Warehousing and moving

During storage, structural elements must be supported by rectangular spacers with a thickness of at least 30 millimeters. When stacking, the spacers should be in the same vertical line.

Armature outlets are protected from damage. Surfaces provided with a texture to ensure better adhesion to concrete also require protection.

Warehousing is carried out taking into account the order of installation. In this case, the factory marking must remain visible.

Metal fasteners (bolts, nuts, etc.) are stored exclusively indoors; they must be sorted by standard sizes, strength class, and in the case of high-strength products - also by batches.

Moving any products by dragging is prohibited. Lifting equipment is used to move or feed to the place of work. Slinging is carried out for mounting loops or in the places indicated in the working drawings.

Let's clarify: ENiR for installation and construction works(document containing uniform norms and prices) is based on the movement of goods weighing up to 50 kg at a distance of up to 30 meters with your own hands, without the use of loading equipment.

The slinging method must exclude the displacement of the slings and damage to the reinforcement. It is forbidden to rafter products for the release of reinforcement. The position of the element during lifting should be as close as possible to the design one (that is, for example, the wall panel is delivered to the work site in vertical position, and the floor panel is horizontal).

Elements rise without jerking and swinging; the desired orientation in space is achieved by using braces (one for vertically oriented elements and at least two for horizontal parts of the structure).

The ascent is done in two steps:

1. The product rises by 20-30 cm to check the quality of the slinging.
2. After verification, further ascent is carried out.

The method of fixing the elements should exclude their displacement at any stage of installation. Before reliable fixation (permanent or temporary), the product cannot be used as a support for other structural elements.

Concrete works

According to SNiP, mixtures prepared in accordance with the following requirements should be used for them:

Dosing of concrete components is carried out by weight. According to the volume of water for mixing, only modifying additives (plasticizers, antifreeze, etc.) can be dosed.

The ratio of components is determined separately for each batch of cement and aggregate with mandatory control of samples for mobility and strength.

It is forbidden to increase the mobility of concrete by introducing water into it.

Before concreting, the surfaces of working joints must be cleaned of dirt, dust, debris, grease stains, cement film, snow and ice. Immediately before the concrete is placed, the surface is washed with water and dried with a stream of air. The instruction is associated with a decrease in the adhesion of cement to the base when the surface is contaminated.

Concrete is laid in horizontal layers of equal thickness.

When vibrating, the vibrator must not rest on reinforcement, embedded parts or formwork. The deep vibrator should be immersed 5-10 cm into the previously laid layer and move in increments of no more than one and a half radius of action; the superficial one moves with a 10 cm overlap of the vibrated area.

Laying the next layer of concrete is permissible either before the previous layer has set, or after it has gained strength of at least 1.5 MPa. The same strength is necessary so that the concrete can be walked on or the formwork of the overlying part of the structure can be installed.

Concrete processing

It may include cutting expansion joints, openings and process holes.

• For all work, SNiP provides for the use of diamond tools. It is quite natural: despite the fact that its price is quite high, cutting reinforced concrete diamond circles is cheaper than the same work performed by conventional abrasives. The reason is the huge difference in wear rate.

Useful: In addition, diamond drilling holes in concrete, in contrast to the use of pobedit drills and crowns, makes the edges of the hole perfectly even.

• The tool is cooled by water with the addition of surfactants, which reduce energy losses to overcome friction.
• The strength of concrete at the time of processing should reach at least 50% of the design.

Reinforcement

Non-weld connections of reinforcing bars are made using annealed binding wire. For butt joints, the use of crimp sleeves and screw couplings is allowed.

It is preferable to use large-block reinforcing products or factory-made meshes.

When installing reinforcement, it is necessary to maintain the thickness of the protective layer of concrete, excluding contact of the reinforcement with atmospheric air and water.

prefabricated structures

How does the document regulate the installation of prefabricated concrete and reinforced concrete structures?

• In the general case, the next tier of a multi-tiered structure is erected not only after the reinforcing frames are joined by welding, but also after the seams are sealed and concrete sets the strength specified in the PPR. Exceptions are specifically stipulated in the project.

Panel housing construction is one of the few exceptions. The seams are closed last.

• Temporary mounting ties can be used to secure the structural element during assembly. Their number, type and procedure for application are again specified in the PPR.
• For concreting joints, it is not allowed to use a solution that has begun to set. The consequence of violating this rule is a catastrophic drop in the compressive strength of the assembly seam.
• Crossbars, load-bearing trusses, inter-column slabs and rafter beams are laid dry on the supporting surfaces of the columns, without mortar. Floor slabs are laid on the mortar; the thickness of its layer should not exceed 20 mm. The surfaces of adjacent slabs are aligned from the side of the ceiling.
• When installing ventilation units, it is necessary to control the filling of horizontal joints with mortar. There should be no gaps.
• Sanitary cabins are placed on gaskets with the alignment of the vertical axis of the risers. Holes for risers are sealed after pressure testing of hot and cold water supply systems.

In the photo - a reinforced concrete sanitary cabin.

• For embedding the seams of prefabricated reinforced concrete structures, concretes based on fast-hardening Portland cements (grade M400 and higher) are used. The use of hardening accelerators is allowed and even recommended. The maximum aggregate grain size in concrete should not exceed 1/3 of the minimum joint section and 3/4 of the minimum distance between reinforcement elements.
• At the time of formwork removal, concrete must reach the minimum strength specified in the project.

Please note: unless otherwise specified, stripping is carried out after reaching 50% of the nominal strength.

• During the installation of welded steel structural elements, shock effects on them are prohibited during low temperatures. To be precise, for steels with a yield strength of 390 MPa or less, the lower temperature limit is -25 ° C, and for steels with a yield strength of more than 390 MPa - 0 degrees.

Conclusion

We hope that the information provided to the reader will be useful. The video in this article, as usual, contains additional materials on the topics we are discussing. Successes in construction!

PROJECT OF WORK PRODUCTION
for the installation of prefabricated reinforced concrete structures of the "cube 2.5" system

1. General part

1. General part

1.1 This project for the production of works was developed for the installation of prefabricated reinforced concrete structures of the "cube 2.5" system at the facility: "Residential development in the Yugo-Zapadny microdistrict". Buildings N 13, 14, 15. Address: Moscow region, Podolsk.

2. Technological sequence of works

2.1 General data

The frame of the KUB-2 5 system is intended for use in residential buildings and public buildings, as well as in ancillary buildings industrial enterprises with the number of floors up to 15 inclusive.

The frame is assembled from prefabricated products with subsequent monolithic nodes.

The frame of the KUB-2.5 system is designed according to a frame or frame-and-frame scheme, the transfer of horizontal forces to columns and stiffeners is ensured by monolithic floor panels, turning them into a hard disk in a horizontal plane.

Load bearing capacity ceilings allows the use of the frame in buildings with an intensity of loads per floor of not more than 1300 kg / m.

The developed frame structures provide for floor heights in buildings of 2.8 m, 3.0 m and 3.3 m with the main column grid of 6.0x6.0 m. For buildings with a height of more than 15 floors, individual development of columns is required.

In the KUB-2.5 system, reinforced concrete compressed-tensioned braces in an ascending pattern were adopted, which ensured spatial rigidity and stability of the frame-bonded version of the system. The bearing capacity of the connection element is determined from the calculation of its work on the longitudinal tensile force.

The section of the element of connections is taken 200x250 mm, reinforcement with 4 bearing reinforcing bars, both ends of which are welded to the embedded loops located at both ends of the element.

2.2 Installation of columns and ties

2.2.1 Preparatory work

Before starting the installation of columns on the foundation, it is necessary to perform the following work:

To make monolithic foundations of glass type, to check the accuracy of the execution of glasses of their binding to the axes of the building. Completed designs are accepted according to the act;

Carry out the preparation of the basement floor;

Make sure that the foundation concrete has gained 70% of the design strength.

Before starting the installation of subsequent columns, the following work must be done:

Install floor guard. Close the openings in the ceilings with wooden shields;

Check the correct installation of the underlying columns and accept them according to the act;

Prepare the necessary mounting equipment;

Concrete monolithic structures(seams) of the underlying columns and floors should gain 70% of the design strength.

2.2.2 Work sequence

2.2.2.1 Work on the installation of columns on the foundation is carried out in the following sequence:

Rinse the glass with water under pressure and make a gravy from cement mortar M-200, the top of which must correspond to the design mark of the bottom of the column;

After the column is fed to the foundation glass, the installers approach it, calm it down from vibrations and lower it into the glass. If the height of the column from the edge of the glass does not exceed 12 cm, then fixing it with wedges from buckling can be considered sufficient; if this size exceeds 12 cm, then it is necessary to install special struts, which are removed after installation and monolithic of the first floor. During the installation of the column, it is necessary to ensure that the longitudinal risks are located in relation to the enclosing structures adjacent to them according to Figure 2;

Using longitudinal marks on the sides of the column, align it vertically and horizontally and then fix the column with 4 steel wedges;

Concrete the sinuses in the glass with fine-grained concrete B25, followed by compaction;

For the installers, install the Aris tower 1x1.5x9.6 m (it is possible to replace it with similar ones in terms of characteristics) and install the telescopic struts to the column. Fasten the second end of the struts to the ceiling with anchor bolts;

Fig.1. Scheme of fixing the column with wedges

Fig.2. Scheme of the location of longitudinal scratches in relation to adjacent structures

2.2.2.2 Installation of columns on top of each other is carried out in the following sequence:

At the storage site, insert a trunnion into the through hole of the column at the level of the upper tier and fix it with pins. Tie a rope to the trunnion and stud (for bridging after mounting the columns). Attach the rope to the column. Install a clip on the column (for attaching telescopic struts) below the mark for the bottom of the overlap with the ribs down;

At the signal of the slinger, move the column to the installation site, while the installers must be outside the danger zone formed from the fall of the column;

After the column has been delivered to the installation site, the installers will approach it and calm it down from vibrations. Align the columns one above the other and lower, while the rod of the lower end of the upper column must enter the branch pipe of the upper end of the lower column. Next, it is worth welding the reinforcement according to the project;

For the installers, install the Aris tower 1x1.5x9.6 m (it is possible to replace it with similar ones in terms of characteristics) and install the telescopic struts to the column. Fasten the second end of the struts to the floor with anchor bolts. The braces may only be removed after the installation of the overlying floor slabs;

After mounting the column, untie it by pulling the pin out of the trunnion and pulling the trunnion out of the column with a rope.

2.2.2.3 Installation of column ties is carried out in the following sequence:

At the storage site, perform a preliminary pairwise assembly of the connection elements into a triangle using a mounting spacer;

Perform welding of support tables to the column;

At the signal of the slinger, apply the connection to the installation site, while the installers must be outside the danger zone formed from the fall of the connection. Reinforced concrete ties are installed "herringbone" in an ascending pattern;

After submitting the connection to the installation site, installers approach it and calm it down from vibrations. Set the connection on the tables and weld;

Concrete the supporting structures with fine-grained concrete B15 within the sectional dimension of the element.

Fig.3. Appearance columns and its nodes

Fig.4. Column connection node

Fig.5. Ties attachment point

2.3 Installation of floor slabs

2.3.1 General data

Floor panels are designed in 2 modifications: single-module with maximum dimensions 2980x2980x160 and two-module - 2980x5980x160. At the ends of the panels there are hinged outlets, which provide a monolithic connection of adjacent panels in the building frame, and mounting tables, which in most cases provide installation of the ceiling without supporting racks.

Single-module floor panels are divided, depending on their location in the frame, into above-column (panels directly supported by columns) NP - inter-column (panels located between above-column) MP - and middle (located between annular) SP.

2.3.2 Preparatory work

Before installing floor panels, make sure that:

Distances between columns correspond to design values ​​within tolerances;

Geometric dimensions of panels (diagonal dimensions, "propeller ratio", etc.), reinforcing outlets, embedded parts, etc. meet design requirements;

There are no technological influxes of concrete that interfere with installation and welding.

2.3.3 Work sequence

The installation option for 2 modular panels provides for the following sequence:

Installation of a 1-module above-column panel NP;

Installation of a 2-module NMP panel;

Installation of a 2-module MSP panel;

Fig.6. Mounting option for 2-module panels

The installation option for I-modular panels provides for the following sequence:

Installation of the above-column panel NP;

Installation of the intercolumn panel MP;

Installation of the middle panel of the joint venture;

Fig.7. Mounting option for I-modular panels

2.3.3.1 Installation of panels is carried out in the following sequence:

Install a mounting jig on the column;

At the signal of the slinger, move the NP slab to the installation site, while the installers must be outside the danger zone formed from the fall of the slab;

After the slab is delivered to the installation site, the installers should approach it, calm it down from vibrations and lower it onto the conductor;

Adjust the level of the panel using specialized bolts on the conductor;

Install telescopic racks under the stove;

Attach the NP panel to the column by welding the shell of the plate with the working reinforcement of the column. After doing welding work it is allowed to remove the conductor;

In the places of installation of inter-column ties, weld the top of the triangle to the shell of the ties of the structural panel;

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