SNP for the installation of prefabricated reinforced concrete structures. All about precast concrete structures. Monolithic reinforced concrete structures

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 finished mounting structures from the design position should not exceed the values \u200b\u200bgiven in table. 12.

Table 12

Parameter	Limit deviations, mm	Control (method, scope, type of registration)
1. Deviation from the alignment of the installation reference points of the foundation blocks and foundation sleeves with the risks of the staking axes
2. Deviation of the marks of the bearing surface of the bottom of the foundation cups from the design ones:
up to the device of the leveling layer on the bottom of the glass
after the device of the leveling layer on the bottom of the glass
3. Deviation from the alignment of reference points (marks of geometric axes, faces) in the lower section of the installed elements with installation reference points (marks of geometric axes or faces of underlying elements, marks of alignment axes):
columns, panels and large blocks of load-bearing walls, bulk blocks
curtain wall panels
crossbars, girders, beams, crane beams, truss trusses, truss beams and trusses
4. Deviation of the axes of the columns one-story buildings in the upper section from the vertical with the length of the columns, m:		Measuring, each element, geodetic executive scheme



St. 16 to 25
5. Deviation from alignment of landmarks (marks of geometric axes) in the upper section of the columns multi-storey buildings with the risks of center axes with the length of the columns, m:



St. 16 to 25
6. The difference in the elevations of the tops of the columns or their supporting platforms (brackets, consoles) of one-story buildings and structures with the length of the columns, m:



St. 16 to 25
7. The difference in elevations of the tops of the columns of each tier of a multi-storey building and structure, as well as the top of the wall panels of frame buildings within the area being verified at:
contact installation
installation by beacons
8. Deviation from alignment of landmarks (risks of geometric axes, faces) in the upper section of the installed elements (crossbars, girders, beams, truss trusses, trusses and beams) on a support with installation landmarks (risks of geometric axes or faces of lower elements, risks of centering axes ) at the height of the element on the support, m:		Measuring, each element, work log

St. 1 to 1.6
St. 1.6 to 2.5
St. 2.5 to 4
9. Deviation from symmetry (half the difference in the depth of support of the ends of the element) when installing crossbars, girders, beams, crane beams, truss trusses, truss trusses (beams), roof slabs and ceilings in the direction of the overlapped span with the length of the element, m:



St. 16 to 25
10. The distance between the axes of the upper chords of trusses and beams in the middle of the span
11. Deviation from the vertical of the top of the planes:
load-bearing wall panels and volume blocks		Measuring, each element, geodetic executive scheme
large blocks of load-bearing walls
partitions, curtain wall panels		Measuring, each element, work log
12. The difference in the marks of the front surfaces of two adjacent non-prestressed panels (slabs) of floors in the seam with the length of the slabs, m:



13. Grade difference upper shelves crane beams and rails:		Measuring, on each support, geodetic executive scheme
on two adjacent columns along a row with a distance between columns l, m:

	0.001 l, but not more than 15
in one cross section of the span:
on columns
in flight
14. Deviation in height of the threshold of the doorway of the three-dimensional element of the elevator shaft relative to the landing area		Measuring, each element, geodetic executive scheme
15. Deviation from squareness inner surface walls of the elevator shaft relative to the horizontal plane (pit floor)	(GOST 22845-85)	Measuring, each element, geodetic executive scheme

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

Note. Depth of support of horizontal elements on bearing structures must be at least 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. The maximum deviation 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 the ground level must be aligned on the inside of the wall, 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 to align elevations and bring them into 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 overlapped span must be carried out in compliance with the dimensions of the depth of their support on the supporting structures established by the project or the gaps between the 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;

under-rafter and truss trusses (beams) when leaning on columns, as well as truss trusses when leaning on under roof 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 truss;

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 (bonded) 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 panels (when panels are overlapped in 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 from entering the channels.

3.30. Volumetric blocks of elevator shafts should be mounted, as a rule, with brackets installed in them for fixing guide cabins and counterweights. The bottom of 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 (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 mortgages and connecting products must be carried out in accordance with Sec. 8.

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 the joints must be documented in the certificates of examination hidden works.

MONOLICHING JOINTS AND SEAMS

3.43. Sealing of joints should be performed after checking the correct installation of structures, accepting the connections of elements in the junctions and performing an anti-corrosion coating of 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 use chemical additives - hardening accelerators. The largest grain size of coarse aggregate in the concrete mixture should not exceed 1/3 of the smallest size of the joint section and 3/4 of the smallest clear distance 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), insulation methods, timing and procedure for stripping and loading structures, taking into account the peculiarities of performing work in winter conditions, as well as in hot and dry weather must be specified 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 into 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. IN winter periods the temperature at which the mastic is applied, as well as the temperature of the mastic at the time of application, must comply with those specified in the technical specifications of the 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 type 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 barrier screens in the form of corrugated metal strips, 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.

Depending on the degree of enlargement, the following methods of mounting structures are used: structural elements or their parts; linear, flat or spatial blocks; structural and technological blocks, consisting of building (usually steel) structures and built-in technological equipment; structures as a whole (poles of power lines, steel chimneys and etc.). In agricultural construction, installation by structural elements is most common. When mounting in blocks, the structures are enlarged before they are installed in the design position. Due to this, the number of lifts and the laboriousness of climbing works are reduced, the number of mounting elements and joints is reduced, and the manufacturability and reliability of the enlarged structure are increased.

According to the accepted sequence of installation of the structure in the span of one-story or on the floor of multi-storey buildings, differentiated (separate), complex (concentrated) and combined (mixed) installation methods are distinguished.

With a differentiated method, within the span or floor, the structures are installed in separate installation kits (tiers). So, in one-story agricultural buildings with a post-and-beam frame, foundations are first mounted, then columns, and after the joints are monolithic, beams (or trusses), floor slabs, wall panels. This method ensures the rhythmic operation of the crane on the installation of the same type of structures using constant equipment, which contributes to an increase in labor productivity. With structures that differ significantly in their mass, several cranes are used, which makes it possible to use their lifting capacity more efficiently. However total number penetrations and parking of erection cranes with this method increases, the start of post-installation work is delayed. A differentiated method is used when using mobile cranes for the installation of reinforced concrete, metal and wooden structures.

With the complex method, all structures are installed within one cell of the building, they are aligned and fixed. The number of movements and stops of the crane is reduced, the start of post-installation work is accelerated, however, the use of the lifting capacity of erection cranes is deteriorating in the case of a significant difference in mass structures. It is expedient to use the complex method when installing one-story buildings of a heavy type with a high saturation of technological equipment. In case of iron installation concrete structures it is necessary to use fast-hardening cements to seal the joints.

In the practice of agricultural construction, a combined installation method is carried out, combining a differentiated method with a complex one (installation of columns within a span, and beams or trusses and roof slabs within one cell).

Depending on the sequence of vertical assembly of structures, the method of building up and growing is distinguished. The extension method consists in the sequential assembly of structures from the bottom up. This is the main method of installation of structures. The growing method is different in that the installation is carried out starting from the upper tiers. On the ground, they collect the uppermost tier of the structure, raise it, then let it down lower tier, connect to the upper one, raise both tiers, etc. This method requires powerful lifting equipment and can only be used with certain structural solutions for buildings.

According to the method of aiming at the supports, the installation is divided into free and forced. With free installation, guidance on the supports is carried out using flexible slings without limiting the movement of the element in space. Mounting accuracy is provided by visual control. Forced installation involves the installation of mounted elements in the design position using special mounting equipment (jigs, manipulators), as well as the directed movement of the element at the time of its installation, using limiting devices and self-locking locking interfaces at the joints.

The choice of a rational installation method is the most important decision of the work execution project. At the same time, the features of the volumetric-constructive solution of this object, the specific conditions of the construction site and the technical and economic indicators of the methods under consideration are taken into account.

40. Installation of prefabricated reinforced concrete structures of one-story industrial buildings.

According to the space-planning structure, one-story industrial buildings of a cellular type are distinguished with shed or flat coatings or span-equal type with coatings in the form of trusses, shells, folds. For the main industries, one-story industrial buildings with a reinforced concrete frame are designed on the basis of unified standard sections, spans, and column steps. When choosing one or another method of installation of an industrial building, one should take into account its structural scheme, the necessary sequence of delivery for installation of technological equipment in separate spans of the building, the location of future technological lines. For one-story light-type industrial buildings with a reinforced concrete frame, a separate method of mounting the structure is more rational. With this method, after the installation of structures and the alignment of the columns, the joints between the columns and the glasses of the foundations are monolithic. By the beginning of the installation of crane beams and the structure of the concrete covering in support riser must gain at least 70% of the design strength. This condition determines the length of the mounting sections. A one-story industrial building of a heavy type is mounted mainly by an integrated method. But at the same time, it is necessary to take measures to root the concrete set at the strength joints.

According to the direction, longitudinal installation is distinguished, in which the building is mounted sequentially by separate spans, and transverse (sectional), when the crane moves across the spans. Apply and longitudinal-transverse installation of the building. In this case, the crane, moving along the span, mounts all the columns, and then, moving across the span, conducts sectional installation. One-story industrial buildings are mounted by specialized streams, each of which is given a set of mounting and transport machines and appropriate mounting equipment. For example, a single-span one-story building can be mounted in 2 flows: installation of columns, roof structures and external fence structures. One-story multi-span buildings can be mounted in several parallel flows.

The installation of columns must be preceded by the acceptance of foundations with a geodetic check of the position of their axes and elevations. Before installing the columns, their dimensions are checked, allowing errors of up to 1 mm, and risks are applied to facilitate the installation of the column in the foundation glass or on the head of the pillars. Heavy columns are usually mounted from vehicles or the columns are pre-layed out with the base facing the foundations. Light columns are usually pre-delivered to the installation area and laid out with their tops facing the foundation. Heavy columns are lifted and placed in a vertical position by turning or sliding. The columns are installed in the foundation glasses after the strength of this solution reaches at least 70% of the design. The column installed in the foundation glass is centered until the marks coincide with the marks on the upper plane of the foundation. To check the verticality of the column, two theodelites are placed at right angles to the digital and alphabetic axes of the building. In this case, the sighting axis of the theodolite is combined with the risks marked on the glass in the lower part of the column, and then the theodolite tube is smoothly raised, with a risk at the upper end of the column. The verified columns are fixed in the foundation glass with the help of conductors or wedges. Reinforced wedges after alignment of the column are left in the column. Columns with a height of more than 12 meters are additionally secured with inventory braces in the plane of their least rigidity.

Crane beams are mounted after the concrete at the junction between the column and the walls of the foundation glass gains at least 70% of the design strength. Crane beams are mounted in a separate stream or simultaneously with roof structures. Before lifting, scaffolding devices are hung on the roll for its temporary fixing in the design position, as well as braces for its precise guidance. The axes of the crane beams are verified with a theodolite installed along axis 1 of the crane beam on a special bracket attached to the first column so that the theodelite is located at a height of 500 mm above the upper plane of the beam. With a span of no more than 18 meters, the axis of the crane beams is verified by measuring the span against each column with a tape measure. Crane beams crane rails leveled with a device installed in the middle of the span of the building at a height of 200-300 mm from the surface of the beam.

Coating trusses are usually mounted from vehicles. In some cases, as well as if it is necessary to enlarge the trusses at the installation site, they are placed in special cassettes in the span being mounted. At the same time, the trusses are laid out in such a way that the crane from each position can install the trusses without a brace and, if possible, lay the floor slabs without moving. Construction trusses and roof beams are mounted after installation and fixing of all underlying structures of the building frame. During installation, the truss is lifted, deployed by means of a brace by 90 0. Then they raise it to a height that is 0.5-0.7 meters higher than the mark of the supports, and lower it onto the supports. The correct installation of beams and trusses is controlled by combining the corresponding risks. For insurance of farms, traverses with semi-automatic grippers are used, which provide remote bridging. After lifting, installation and alignment, the 1st truss or beam is fastened with braces, and the subsequent ones are fixed with special struts at the rate of at least 2 for trusses with a span of 24-30 meters. The braces and spacers are removed only after the installation and welding of the coating panels.

Coating slabs are preliminarily stored in the area of action of the assembly crane. The number of stacks of plates and their location is determined from the condition of covering the cell between 2 trusses from one crane station. Coating slabs are mounted immediately after the installation of the permanent fastening of the next truss. This ensures the rigidity of the assembled building frame cell. The plates should be mounted with a symmetrical loading of the truss, they are welded to the embedded parts and released from the slings only after welding at 3 points. After installing the plates, the joints are monolithic.

Installation of wall panels is a labor-intensive process, in which labor costs can account for 30-40% of labor costs during the installation of the above-ground part of the building. Installation of wall panels is usually carried out in a separate stream immediately after the concrete has set the required strength in this area at the joints between columns and foundations. Large-sized wall panels up to 12 meters long, as a rule, are mounted from vehicles using wall cranes or special installers in the form of self-propelled tower units equipped with a self-elevating mounting platform.

42. Sealing of joints of prefabricated reinforced concrete structures. Installation work in winter conditions. Safety engineering.

The strength of their consts depends on the quality of sealing the assembly joints of the reinforced concrete structures spatial rigidity and building stability. Sealing of a joint consists of a trace. processes: welding and protection of embedded parts from corrosion, embedding joints with mortar or concrete mixture, joint sealing (mainly for wall panels).

The complexity of sealing joints is 75-80% of the total labor intensity of installing floor slabs and wall panels.

Welding of reinforcing outlets and embedded parts. Welding of embedded parts and reinforcement extensions of butt joints is started after checking the correctness of their location and thorough cleaning from dirt, rust, ice.

The outlets of reinforcing bars at the joints and nodes of prefabricated reinforced concrete structures are welded, depending on the diameter of the reinforcement, with an overlap or with overlays for rods with a diameter of 8 to 20 mm; for rods with a diameter of more than 20 mm, semi-automatic DC bath welding is used.

The surface of welded joints must be smooth, finely flaky, must not have undercuts, undercooking, pores and other visible defects. The welder who conducts welding puts a stamp on the joints welded by him and enters data on the performance of welding work in a log. Depending on the type of joint, the quality of the weld is checked by examining, drilling and etching with acid the defective sections of the welds in order to eliminate the failure of the weld root. Internal weld defects can be detected using ultrasonic or gamma electroscopies.

Metal parts must be protected from corrosion. Protected by electrochemical method.

To reduce the complexity of sealing joints and increase the reliability of the junctions of columns of multi-storey buildings, the use of non-welded adhesive joints is used. The most technologically advanced are cellular joints.

In such joints, the reinforcing outlets of the mounted elements of the columns are led with the help of special conductors into the sockets available at the ends of the previously installed columns.

Sealing joints.

Monolithic joints are produced with a sand-concrete mixture or a concrete mixture, in which crushed stone serves as an aggregate. With a larger joint volume, concrete mixtures are usually used. The duration of the process of monolithic spatial structures should be minimal. Therefore, fast-hardening cements are used to seal the joints. When sealing the joints between the outer panels large-panel buildings or between curtain panels industrial buildings perform sealing, excluding the penetration of air and moisture into the room. Joint sealing works are carried out from suspended cradles or self-propelled towers in the following order:

They clean the gaps of the joints, cover the gaps of the joint with mastic isol using special. pneumatic apparatus, poroizol gaskets are wound with a special roller. In this case, the gaskets should be 30-50% wider than the gap.

Installation work in winter conditions.

In the production of installation work in winter conditions, the most vulnerable point is the joint of prefabricated reinforced concrete structures. When embedding butt joints in winter conditions, measures should be taken to prevent freezing of concrete in the joint until it reaches critical strength, the value of which depends on the type of structure and the timing of its commissioning. To achieve critical or design strength with mortar or concrete before freezing, the joint cavity should be preheated and concrete or mortar heated to a temperature of at least 20 degrees should be laid, followed by maintaining the required temperature of isothermal heating.

Embedded parts and outlets of reinforcement at the joints are welded at an outside air temperature of at least -30 degrees.

Sealing methods:

Freezing, - an introduction to concrete antifreeze additives, - heat treatment of concrete.

Availability negative topics outside air imposes certain restrictions on the process of sealing joints. So, sealing joints with mastics is allowed at temperatures not lower than -20 degrees.

Safety engineering.

The requirements of safety rules must be taken into account already at the design stage of the facility. Safe installation should also be considered at the stage of development of the installation project. I allow workers to install the structure and related work after an introductory briefing, during which they are introduced to the rules for safe work, taking into account the specific features of the bottom building or structure.

For installation and welding work at height, I admit specialists who have a certificate of medical examination, which they undergo twice a year. For climbing work, installers with a category of at least 4th and experience of at least one year are allowed. All workers must wear hard hats; when working at height, they must wear safety belts. When moving from node to node of the structure to be mounted, the workers attach the carabiner of the belt to a tensioned steel safety rope.

In order to create safe conditions to build. The site in the building to be installed must have warning labels, identified hazardous areas, fenced openings, and workplaces in the evening and at night are adequately lit.

Special precautions should be taken in windy weather, with a wind of more than 6 points, the installation work associated with the use of cranes is stopped, as well as at a height and in an open place.

Mounted structures are kept from swinging and rotating with the help of braces.

Much attention during installation should be paid to electric welding, because. when performing them, in addition to the danger of electric shock, there is also a fire hazard. It is forbidden to weld in the rain, during a thunderstorm, heavy snowfall and wind. The welder must work in overalls and with a mounting belt.

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.

3.3. In cases where the strength and stability of structures during the assembly process are ensured by welding field joints, 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.

3.5. 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

Parameter	Limit deviations, mm	Control (method, scope, type of registration)
1. Deviation from the alignment of the installation reference points of the foundation blocks and foundation sleeves with the risks of the staking axes	12
2. Deviation of the marks of the bearing surface of the bottom of the foundation cups from the design ones: up to the device of the leveling layer on the bottom of the glass after the device of the leveling layer on the bottom of the glass	-20	Same
3. Deviation from the alignment of reference points (marks of geometric axes, faces) in the lower section of the installed elements with installation reference points (marks of geometric axes or faces of underlying elements, marks of alignment axes): columns, panels and large blocks of load-bearing walls, bulk blocks of curtain wall panels crossbars, girders, beams, crane beams, truss trusses, truss beams and trusses	8	" Measuring, each element, work log
4. Deviation of the axes of the columns of one-story buildings in the upper section from the vertical with the length of the columns, m:	20	Measuring, each element, geodetic executive scheme
5. Deviation from the alignment of landmarks (marks of geometric axes) in the upper section of columns of multi-storey buildings with marks of centering axes with the length of the columns, m:	12	Same
6. The difference in the elevations of the tops of the columns or their supporting platforms (brackets, consoles) of one-story buildings and structures with the length of the columns, m:	14	Same
7. The difference in elevations of the tops of the columns of each tier of a multi-storey building and structure, as well as the top of the wall panels of frame buildings within the area being verified at: contact installation installation by beacons	12+2n	Same
8. Deviation from alignment of landmarks (risks of geometric axes, faces) in the upper section of the installed elements (crossbars, girders, beams, truss trusses, trusses and beams) on a support with installation landmarks (risks of geometric axes or faces of lower elements, risks of centering axes ) at the height of the element on the support, m: St. 1 to 1.6	6	Measuring, each element, work log
9. Deviation from symmetry (half the difference in the depth of support of the ends of the element) when installing crossbars, girders, beams, crane beams, truss trusses, truss trusses (beams), roof slabs and ceilings in the direction of the overlapped span with the length of the element, m:	5	Same
10. The distance between the axes of the upper chords of trusses and beams in the middle of the span	60	Same
11. Deviation from the vertical of the top of the planes: load-bearing wall panels and volume blocks large blocks of load-bearing walls partitions, curtain wall panels	10	Measuring, each element, geodetic performance scheme Measuring, each element, work log
12. The difference in the marks of the front surfaces of two adjacent non-prestressed panels (slabs) of floors in the seam with the length of the slabs, m:	8	Same
13. The difference in the marks of the upper shelves of the crane beams and rails: on two adjacent columns along a row with a distance between columns l, m: l<= 10 l > 10 in one cross section of the span: on columns in flight	10 0.001 l, but not more than 15	Measuring, on each support, geodetic executive scheme
14. Deviation in height of the threshold of the doorway of the three-dimensional element of the elevator shaft relative to the landing area	+/-10	Measuring, each element, geodetic executive scheme
15. Deviation from perpendicularity of the inner surface of the walls of the elevator shaft relative to the horizontal plane (pit floor)	30 (GOST 22845-85)	Measuring, each element, geodetic executive scheme
The designation adopted in Table. 12: n - the serial number of the tier of columns or the number of panels installed in height. Note. The depth of support of horizontal elements on the supporting structures must be at least specified in the project.

Installation of foundation blocks and walls of the underground part of the building

3.9. The installation of blocks of strip foundations and basement walls should be carried out, 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. The maximum deviation 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.

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.

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.

3.16. 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 crossbars, beams, trusses, floor slabs and coatings

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

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 (bonded) 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.

3.24. 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.

Installing wall panels

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 panels (when panels are overlapped in 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
produce:

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 level of the top of the panel - by combining (using a template) the edge of the panel with the notch 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, volumetric blocks of lifts and sanitary 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. The joints of the ventilation ducts of the blocks should be thoroughly cleaned of the solution and prevent it and other foreign objects from entering the ducts.

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. Holes 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 lifting floors

3.33. Floor slabs should be lifted after the concrete reaches the strength specified 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. 8.

3.38. Anti-corrosion coating of welded joints, as well as areas of embedded parts and connections, should 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.

3.40. 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.

Sealing joints and seams

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

ConsultantPlus: note.
Instead of GOST 7473-85, by the Decree of the Ministry of Construction of the Russian Federation of 06/26/1995 N 18-61, GOST 7473-94 was put into effect on January 1, 1996.

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 use chemical additives hardening accelerators. The largest grain size of coarse aggregate in the concrete mixture should not exceed 1/3 of the smallest size of the joint section and 3/4 of the smallest clear distance 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:

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.

ConsultantPlus: note.
Instead of GOST 10180-78 by Decrees of the USSR Gosstroy dated 12/29/1989 N 168 and dated
05/24/1990 N 50 from January 1, 1991 GOST 10180-90 and GOST 28570-90 were put into effect
respectively.

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

Water, air and heat insulation of joints of external walls of prefabricated 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 overlapping 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). In places of intersection of joints of a closed type, sealing gaskets should first of all be installed in horizontal joints.

3.63. In closed-type joints when overlapping external wall panels, in drained-type horizontal joints (in the area of the drainage apron), in open-type horizontal joints, as well as in joints of tongue-and-groove panels, 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.

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. In winter periods, the temperature at which the mastic is applied, as well as the temperature of the mastic at the time of application, must comply with those specified in the technical specifications of the 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 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 of 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 type 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 barrier screens in the form of corrugated metal strips, 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.

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 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.

Classification

What types of reinforced concrete structures are used in construction?

Monolithic. Most good example- 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 ready-made 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. 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 stress implies industrial conditions.

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

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 the 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 contents of the last document: it contains the most complete information on 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.

Installation of reinforced concrete and metal structures of prefabricated type in the conditions of a construction site.
Welding of field joints of metal structures, welding of reinforcement joints 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 according to 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.

To clarify: ENiR for installation and construction work (a document containing uniform norms and prices) proceeds from 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 a vertical position, and the floor panel - in a horizontal position).

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:

The product rises by 20-30 cm to check the quality of the slinging.
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 required 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 of 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, which excludes 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.

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.

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: in the absence special instructions 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!

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Topic 7 "Installation of precast concrete structures"

Issues under consideration:

General information

Methods for the production of installation work

Features of installation of one-story industrial buildings.

1General information

Installation of reinforced concrete structures is the process of their assembly, i.e. installation and fixing in the design position. Installation includes three types of work:

1. Preparatory:

Unloading vehicles

Warehousing

pre-assembly

2. Basic

Slinging

Moving to the installation site

Pointing, lowering and installation of elements

Their temporary fixing and alignment with fine-tuning to the design position, final fixing, embedding of joints (seams).

3. Final

Sealing a joint (seam) is the process of sealing it with concrete or cement mortar

Transportation of reinforced concrete products. Prefabricated structures must be delivered from the manufacturer to the construction site without damage. The enterprise is responsible for loading, and the transporting organization is responsible for safety.

To avoid damage, prefabricated products are placed on vehicles, if possible, in the design position (panels of walls and partitions in a vertical position or slightly inclined, truss beams - in the “on edge” position, other elements - in a horizontal position.

Transportation of reinforced concrete products can be carried out by road and railway transport.

Installation of prefabricated reinforced concrete structures should be carried out directly from vehicles (“from wheels”), there are three schemes for organizing work “from wheels”:

2. Semi-shuttle

3. Shuttle

With a pendulum scheme, a tractor with a trailer is loaded in a warehouse, transports the product to the facility, stands in the installation area of the crane, and the crane mounts the product directly from the vehicle. At the same time, the tractor is idle waiting for unloading, and after removing the last product, it leaves the construction site and moves to the warehouse. The number of trailers in this scheme is equal to the number of tractors.

In cases where the downtime of the tractor at the facility, waiting for unloading, exceeds 20% of the cycle time of its operation, a semi-shuttle scheme is used.

With a semi-shuttle scheme, the number of tractors is 1 less than trailers, because after delivering the product to the facility, the trailer is unhitched from the tractor in the installation area of the crane. At the time when the crane is unloading and assembling the products, another, already released trailer is attached to the tractor, with which the tractor moves to the warehouse for the next loading of products. If even with this scheme, the downtime of the tractor reaches 20% or more of the process time, then a shuttle scheme is used.

With the shuttle scheme, the number of tractors is 2 less than the number of tractors than trailers. With this scheme, the organization of work is as follows: having brought the products to the facility, the tractor unhooks from the loaded trailer, hooks up the freed trailer and goes to the warehouse. There, the empty trailer is uncoupled, left for loading, and the loaded trailer is attached to the tractor and moved to the object. those. trailer-uncoupler is carried out both at the facility and at the warehouse. In order to calculate how many products can be transported in a particular car, you need to know the weight of the transported product, the carrying capacity vehicle and observe the conditions so that the load factor is in the range of 0.8-1

P is the mass of transported products

Q is the load capacity of the machine

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Lecture 16. Installation of precast concrete and concrete structures. Continuation of the topic.

11.Methods of installation of structures of buildings and structures according to the degree of enlargement of structures, according to the sequence of installation of elements

Manifold constructive solutions buildings and structures requires the use of various methods and techniques for their installation. The choice of the method of building a building depends on its design and technological features, the degree of enlargement of elements, the material of structures, mechanization and other factors.

Methods of installation of structural elements are directly dependent on the degree of enlargement of the assembly elements, the sequence of installation of prefabricated elements, the method of installing structures in the design position, the means of alignment and temporary fastening of elements, and other features.

Mounting methods according to the degree of enlargement of elements. Depending on the degree of enlargement of structures, installation is divided into small-element, element-by-element, large-block, complete-block and installation of structures in finished form.

Small-element assembly of individual structural elements is characterized by significant labor intensity, incomplete loading of assembly mechanisms due to the large difference in the masses of various mounted elements, a large number of lifts, and sealing of numerous joints. Often there is a need for a device scaffolding for fixing individual elements and pre-assembly directly in the structure. The method is ineffective and is rarely used.

Piecemeal installation of individual structural elements (columns, crossbars, floor panels, etc.) requires a minimum of preparatory work. They are widely used in the construction of civil and industrial buildings, their installation from an on-site warehouse and from vehicles.

Large-block installation of geometrically invariable flat or spatial blocks, pre-assembled from individual elements. The mass of the blocks is adjusted, if possible, to the maximum carrying capacity of the mounting mechanisms. At the same time, the number of assembly lifts is reduced, the execution at the height of most assembly operations. Examples of a flat block are a frame of a multi-storey building frame, a block of a covering shell; spatial elements - roof blocks of one-story industrial buildings per cell size, including trusses, ties, roof structures.

Complete-block installation implies the full degree of factory readiness of large blocks the size of a cell, including already installed communications - sanitary, electrical, ventilation, located between the truss belts. In civil engineering, the method includes the installation of block rooms and block apartments. The building being erected is divided into large-sized, but transportable, structurally finished, fully finished (painting, finishing, floors) and equipped with equipment assembly blocks, which are delivered to the installation site and assemble the buildings. The mass of such mounting blocks can reach 100 tons.

Installation of structures in finished form involves the assembly of the structure completely at ground level with the final connection and fixing of all nodes, followed by the installation of the structure in the design position. The method is used when installing power line supports, radio towers, shells, factory pipes, etc.

Ways of aiming mounting elements on supports. Depending on the method of installation of the structure in the design position, the following types of installation are distinguished.

Free mounting, in which the mounted element is installed without any restrictions in the design position with its free movement. The method requires constant monitoring of the position of the element in space during its installation, the need to perform alignment, fastening and other operations at a height. The disadvantages of this method are the increased complexity and high labor intensity of the work.

Restricted-free mounting is characterized by the fact that the mounted structure is installed in guide stops, clamps and other devices, which partially restrict the freedom of movement of the structure, but lead to a reduction in labor costs for temporary fastening and alignment. The method improves the performance of crane equipment by reducing the assembly cycle time.

Forced installation of the structure is based on the use of conductors, manipulators, indicators and other means that provide complete or specified limitation of the movement of the structure from the action of its own mass and external influences. The method provides an increase in the accuracy of installation, leads to a significant reduction in labor costs.

Installation methods according to the sequence of installation of elements. When assembling the structures of buildings and structures, the following requirements must be observed:

the sequence of assembly must ensure the stability and geometric invariability of the assembled parts of the building at all stages of installation;

installation of structures on each section of the building should allow subsequent work to be carried out on the mounted section;

safety of installation, general construction and special works at the facility, taking into account their implementation according to a combined schedule.

Depending on the adopted sequence, the installation of structural elements is carried out by the following methods: differentiated (separate), complex and mixed (combined).

The differentiated or separate method is characterized by the installation of the same type of structural elements, including their temporary and final fixing. For one-story industrial buildings, all columns are first installed, then all crane beams, with the last penetration of the installation crane, wall elements are hung. In multi-storey residential buildings, wall panels, partitions, sanitary cabins and other elements are sequentially mounted. The work on the floor is completed with the laying of floor panels.

The complex method provides for the sequential installation, temporary and final fixing of various structural elements that make up the frame of one cell of the building. The installation of the elements of another cell begins after the design fixing of the structures of the previous cell. The advantage of this scheme is the ability to proceed earlier to subsequent finishing work and installation of technological equipment in cells completed by installation. The method is used in the installation of multi-storey frame and frameless buildings, single-storey industrial buildings with a metal frame.

A mixed or combined method is a combination of separate and complex methods. Mixed installation is most often used for one-story industrial buildings made of precast concrete. All columns are installed in the first installation stream, in the second stream - crane beams, roof trusses and covering panels are mounted in the cells, wall panels are hung in the third stream. The method is effective when it is possible to provide each assembly stream with independent assembly tools. Mounting with the necessary shift in time can be provided by all three mounting mechanisms, which leads to a significant reduction in the time of installation work.

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Installation of precast concrete structures

Installation of prefabricated reinforced concrete structures of buildings, as a rule, is carried out element by element.

The installation of rafters in a vertical plane is carried out by aligning their geometric axes on the supports relative to the vertical. 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. If a gasket package is used, they must be welded together and the package welded to the base plate.

Installation of floor slabs is carried out according to the markings on the support beams, which determine their design position. The installation of the slabs of the coating is carried out according to the embedded parts in the shelf of the rafter beams. Floor slabs are laid on a layer of mortar with a thickness of not more than 20 mm, coating slabs - dry.

Wall panels are installed according to embedded parts on reinforced concrete columns or pre-marked risks on rafter columns. Alignment of panels should be carried out in the plane of the wall and in the vertical plane. After checking the correct installation of the structures and accepting the connections of the elements in the junction nodes, the joints are monolithic.

Acceptance of finished concrete and reinforced concrete structures is formalized by an act in the prescribed form.

Installation of enclosing structures

The walls of the vertical and horizontal cuts are mounted, as a rule, with their preliminary pre-assembly into the so-called "cards". With an appropriate feasibility study, element-by-element installation is allowed. The pre-assembly of wall panels into "cards" must be carried out on stands in the area of the main assembly crane.

The installation of "cards" and panels in terms of and in height is carried out by combining the installation risks marked on the mounted and supporting structures. The top of the panels is aligned relative to the center axes. Before installing the panels, sealing gaskets are laid in vertical and horizontal joints. When accepting the walls, the reliability of fixing the panels, the absence of damage, fluctuations are checked. Thermal insulation of joints between panels is subject to intermediate control.

The joints of the coating of metal panels that do not have a waterproofing carpet should be sealed with metal overlays, while the sides of the upper sheathing of the panels along the entire length should have a height of at least 60 mm.

Concrete works

Dosing of the components in the preparation of the concrete mix should be done by weight. Dosing of additives introduced into the concrete mixture in the form of aqueous solutions is allowed, according to the volume of water. Aggregates for concrete are used fractionated and washed. It is forbidden to use a natural mixture of sand and gravel without sieving into fractions.

Transportation and supply of the concrete mixture is carried out by specialized means that ensure the preservation of the specified properties of the concrete mixture.

Before concreting, all surfaces are thoroughly cleaned of debris, dirt, oils, snow, ice, cement film. Concrete mix they are laid in concrete structures in horizontal layers of the same thickness without gaps with a consistent direction of laying in one direction in all layers.

In the initial period of hardening, concrete must be protected from atmospheric precipitation and moisture loss, and then it is necessary to maintain a temperature and humidity regime to create conditions that ensure the growth of its strength.

Measures for the care of concrete, the procedure and timing of their implementation, control over their implementation and the timing of the stripping of structures should be established by the PPR.

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Installation of prefabricated reinforced concrete and concrete structures

1.General installation instructions

3. Installation of columns and frames

4. Installation of crossbars, beams, trusses, floor slabs and coatings

5. Installation of wall panels

6. Installation of ventilation units, volumetric units of elevator shafts and sanitary cabins

7. Construction of buildings by lifting ceilings

8. Welding and anti-corrosion coating of embedded and connecting products

9. Casting joints and seams

10. Water, air and heat insulation of the joints of the outer walls of prefabricated buildings

1.General installation instructions

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.

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.

In cases where the strength and stability of structures during the assembly process are ensured by welding field joints, 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.

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.

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.

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.

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. SNiP 3.03.01-87 "Bearing and enclosing structures".

In the process of installation, measurement control should be carried out, a geodetic executive scheme should be drawn up. The results of the control should be recorded in special journals.

2. Installation of foundation blocks and walls of the underground part of buildings

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.

The installation of blocks of strip foundations and basement walls should be carried out, 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.

Foundation blocks should be installed on a layer of sand leveled to the design mark. The maximum deviation 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.

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 the ground level must be aligned on the inside of the wall, and above - on the outside. Vertical and horizontal seams between blocks must be filled with mortar and embroidered on both sides.

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Types and methods of installation of steel and reinforced concrete structures

The main purpose of reinforced concrete structures is 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 the bearing element is expected. 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 - mainly the work of 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;
Installation of structural elements of the building frame;
Installation ventilation elements and blocks;
Installation internal elements 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, preparatory work should be carried out. Since these structures are of considerable weight, it is necessary to consider the entrance to the construction site of vehicles and special equipment (for example, 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 place of assembly, the structures are laid out in the 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 should lie on top, the bottom row or especially heavy structures are stacked on wooden substrates, it is necessary to provide for free access of equipment to each structure and the possibility of capturing the part by the crane boom, as well as the convenience of slinging.

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, use different ways lifting - rotary, 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 related to the load on the column, as well as the laying of beams, is 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. The anchor bolt washers should also be welded. 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 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.

Features of metal structures

A distinctive feature of metal building structures is their tendency to deformation, significant weight and special precision in manufacturing. Therefore, transport, stacking, lifting and installation require special care and caution.

In general, the installation of metal and reinforced concrete structures does not fundamentally differ, but metal products are often prefabricated, which allows them to be assembled not only on the ground, but also directly on the installation site.

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Installation methods for reinforced concrete structures of frame buildings

Methods and technology for mounting elements of frame buildings depend on their design solutions, the number of storeys and the available mounting equipment.

Frames of multi-storey buildings with columns of two-story cutting are recommended to be mounted using group or articulated conductors. This provides forced fixation of the columns in the design position during their installation, thereby reducing the amount of alignment work. The remaining elements of the frame are mounted by a free method.

Frames of one-story and low-rise industrial and administrative buildings are recommended to be mounted using a limited-free method using single or group conductors.

The most important rule that must be followed for any organization and installation methods is to ensure the stability of the structures being mounted. In this regard, any installed structure cannot be released from the crane hook until it is securely fastened. The sequence of installation of the frame elements must be such as to ensure the rigidity and geometric invariability of the mounted part of it.

Taking into account this requirement, when erecting the frame of one-story industrial and other buildings, it is recommended to observe the following sequence: the first to install structures in each section (grip) between which there are connections (vertical, horizontal, etc.). Every next structural element attached to the previously installed connecting elements provided for by the project: crossbars, ties or temporary struts and ties.

Prefabricated elements of multi-storey buildings in each grip (section) are mounted in the following sequence. First, the columns and crossbars of the frame are installed in the stiffness cell or starting from the end of the building (section) along its entire width and on all floors of the tier. After reconciling the position of the columns and crossbars and fixing them, ties or tie panels and spacer floor slabs are installed between the columns. Then mount internal panels staircase, landings and marches, external wall panels of a staircase, ventilation blocks, sanitary cabins, wall panels of external walls and partitions. After assembling the elements of one section and fixing them by welding, the crane is moved to the next section, and welding is completed on the assembled section, the joints are monolithic, and floor slabs are mounted. In the same sequence, installation work is performed in all subsequent sections of the tier.

The installation of the second tier is started only after reconciliation installed structures, welding of all assembly joints of the first tier and control by geodetic instruments of the correct installation of structures and breakdown of axes and marks for the subsequent installation of structures.

Before starting the installation of structures on each tier, which may include two or three floors (depending on the cutting of columns along the height of the building), mark the main centering axes of the building on the ceiling or column heads, determine the installation horizon, mark axial and other installation risks. The risks of the axes are measured each time from the main center axes and checked mutual arrangement adjacent axes.

The most common multi-story residential, public and industrial frame buildings are with frame cells of 6 x 6 and 9 x 9 m, other spans are also possible, for example, 12 m and intermediate ones. Floor height 3; 3.3; 3.6; 7.2 m. The width of buildings is most often 12; 18; 24 and 36 m. On the upper floors there can be halls up to 10.8 m high, spanning the entire width of the building or part of it, including with or without overhead cranes. The length of the building is a multiple of the cell parameter.

For load-bearing frames, columns are used for one, two, three floors. Depending on the space-planning solutions, buildings are built with a transverse or longitudinal arrangement of crossbars, along which floor slabs are laid, respectively, in the longitudinal or transverse direction.

Assembling the frame of buildings is an interconnected process of mounting columns, crossbars, stiffening diaphragms, bonded and interfloor floor slabs. The elements are installed in such a sequence that ensures the rigidity and spatial invariability of the frame. The sequence of installation in each case is determined by the design of the production of works and a set of mounting equipment that will be used to install and align structures: individual (single) or group fixtures.

Installation using individual means of mounting equipment.

In construction, individual means of mounting equipment are most often used, with the help of which structures are calibrated and temporarily fixed. The kits of individual mounting equipment for mounting multi-storey frames include (see the diagram below, pos. a ... c): wedges and liners, support beams, anchor devices, clamps, struts and horizontal struts, conductors. Unlike group remedies, individual remedies are more versatile and easy to use (Fig. 1).

Rice. 1 - Schemes for installing multi-storey columns using a set of individual mounting equipment: a - the location of the columns and fixtures, b - fixing the column with braces, c - a clamp for fixing the braces to the column; 1 - foundation glass, 2 - inventory beam, 3 - column, 4 - clamp, 5 - brace, 6 - brace hitch, 7 - wedges, 8 - anchor device, 9 - crimp rope

Wedges and wedge inserts are used to align and secure columns in foundation glasses.

The support beams consist of two channels connected by planks and have loops in the upper part for attaching the struts, and in the lower part - end stops for fixing to the foundation glasses (see diagram above, pos. a, b).

Anchor devices 8 are a U-shaped frame with holes in the upper part, through which a gripping hook passes, moved with a tension nut.

The clamp (see diagram above, pos. c) for attaching the strut to the column is made in the form of an angular stop, which is fixed to the column with a rope with a tensioner.

The struts 5 consist of telescopically connected pipes with tension towbars 6 and grippers at the ends for fastening to the loops or eyelets of the clamp and loops of support beams or other structures.

Conductors are designed for temporary fixing and alignment of columns joined in height with the heads of previously installed columns.

The columns of the first mounting tier are installed by the same methods as in the installation of one-story buildings. However, at the same time, struts and spacers are installed to hold the columns in such a way that they do not interfere with the laying of crossbars and tie plates between the columns. Prior to the installation of the columns, support beams 2 are laid on the grip (see the diagram above) and fastened to the foundation hinges using anchor devices. Support beams are not laid in those places where frame stiffening diaphragms are installed.

A clamp 4 is put on the mounted column in the warehouse and two struts 5 are hung on it, after which the column is raftered and lifted by a crane. The column submitted for installation is installed in the foundation glass and temporarily fixed with the help of wedge inserts (wedges) 7 and two struts 5. After that, the column is unstrapped and aligned. The vertical position of the column is set using theodolites along two axes. As the installation progresses, the columns are monolithic in the glasses of the foundations. The struts are removed from the columns after the frame is unfastened with crossbars and slabs at the level of the two lower floors.

The crossbars are mounted after the columns (see the diagram below, pos. a ... c). Before installation, the crossbars are cleaned, the reinforcing outlets are straightened, and the embedded parts and the crossbars are supported dry on the consoles of the columns. On each structural cell of the building, first the lower and then the upper crossbars are mounted. Workplace installers - at the inventory sites.

Work is performed in this sequence. The installer of the 3rd category rafters the crossbar and gives the command to the crane operator to lift. The driver delivers the crossbar to the installation site with a crane. The fitter of the 5th category directs the operation of the crane. Installers of the 4th and 3rd categories, being on the adjustable scaffolding platforms, take the crossbar, put it on the shelves and align it.

In the transverse direction, the crossbars are set to the design position, aligning their axes (projections of the upper reinforcement) with the axes (projections of the reinforcement) of the columns, in the longitudinal direction - observing equal areas for supporting the ends of the crossbar on the console of the columns (the difference in the areas for supporting the ends of the crossbar on the console should not exceed ± 5 mm).

After alignment of the crossbars, their supporting embedded parts are welded with a tack to the embedded parts of the consoles of the columns, and the crossbar is unslinged (Fig. 2).

Rice. 2 - Installation of the crossbar: a - drawing an axial risk on the column, b - installation of the crossbar, c - straightening of the crossbar during alignment

After making sure that the columns and crossbars in the assembled cell are in the design position, the installers finally fix the crossbars by bath welding of reinforcement outlets, welding of embedded parts, and embedding joints (after delivery according to the welding work report). Then, frame rigidity diaphragms are mounted (see diagram below, pos. a, b) with a shelf replacing the crossbar (Fig. 3).

Rice. 3 - Installation of internal walls - stiffening diaphragms - in a frame building: a - installation, b - temporary fixing; 1 - brace, 2 - diaphragm with a shelf that replaces the crossbar, 3 - universal sling, 4 - adjustable clamp with a stand

Adjustable clamps 4 are used for temporary fastening and alignment of diaphragms. Frame stiffening panels without a shelf that replaces the crossbar are mounted before the crossbar is installed in this span. At the same time, instead of temporary frame fasteners, equivalent fasteners are placed on the other side of the column at the diaphragm installation site, for example, horizontal braces. The organization of the workplace and the sequence of operations are shown in the diagram below, pos. a, b.

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SNP for the installation of prefabricated reinforced concrete structures. All about precast concrete structures. Monolithic reinforced concrete structures

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

INSTALLATION OF COLUMNS AND FRAMES

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

WALL PANELS INSTALLATION

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

CONSTRUCTION OF BUILDINGS BY THE METHOD OF LIFTING FLOORS

WELDING AND ANTI-CORROSION COATING OF EMBEDDED AND CONNECTING PRODUCTS

MONOLICHING JOINTS AND SEAMS

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

Installation of foundation blocks and walls of the underground part of the building

Installation of columns and frames

Installation of crossbars, beams, trusses, floor slabs and coatings

Installing wall panels

Installation of ventilation units, volumetric blocks of lifts and sanitary cabins

Construction of buildings by lifting floors

Welding and anti-corrosion coating of embedded and connecting products

Sealing joints and seams

Water, air and heat insulation of joints of external walls of prefabricated buildings

Classification

Regulations

SNiP 3.03.01-87

Warehousing and moving

Concrete works

Concrete processing

Reinforcement

prefabricated structures

Conclusion

Topic 7 "Installation of precast concrete structures"

1General information

Lecture 16. Installation of precast concrete and concrete structures. Continuation of the topic.

11.Methods of installation of structures of buildings and structures according to the degree of enlargement of structures, according to the sequence of installation of elements

Installation of precast concrete structures

Installation of enclosing structures

Concrete works

Installation of prefabricated reinforced concrete and concrete structures

2. Installation of foundation blocks and walls of the underground part of buildings

Types and methods of installation of steel and reinforced concrete structures

Classification of reinforced concrete structures

Types of work during the installation of structures

Initial construction stage

Foundation installation

Installation of columns

Installation of beams and roof trusses

Mounting plates

Installation of wall panels

Features of metal structures

Installation methods for reinforced concrete structures of frame buildings