Types and methods of installation of steel and reinforced concrete structures in the construction of buildings and structures. Installation of columns in foundation sleeves Methods of installation of metal and precast concrete structures
The main material of the construction industry is concrete. From it, structures and their elements of various types and purposes are produced in the factory, at landfills, directly at construction sites, which form the supporting structure and appearance of structures. Regulatory documents establish practical requirements for the process of installation of concrete and reinforced concrete products.
What are reinforced concrete structures?
Products are divided into prefabricated, monolithic, prefabricated-monolithic. The first are factory samples that are combined into a frame or connected to it by welding and subsequent concreting. The second ones are cast on objects, the frames of which will take increased loads (foundation slabs, self-supporting frames, etc.).
The latter - in a rational way combine heterogeneous elements of the first and second types. Factory designs are equipped with conventional and (increases resistance to bending loads). Monolithic products contain only a conventional reinforcing cage.
SNiP 3.03.01-87, which establishes standards for all stages of installation of reinforced concrete structures, technologies and materials. GOST 10922-90, which establishes the general conditions for the formation of products from reinforcement and their welding in reinforced concrete structures. GOST 14098-91, which standardizes the types of structural design, geometric parameters of joints when welding embedded parts and fittings. The requirements of the listed documents are included in the project for the production of work at construction sites (PPR). 
How are structures installed?
Installation of prefabricated concrete and reinforced concrete structures includes:
- intermediate storage and movement of products;
- installation of reinforced concrete products from prefabricated elements;
- reinforcement in monolithic structures;
- pouring and care of concrete to curing;
- concrete processing.
Warehousing and moving
Placement of products on the construction site is carried out taking into account the sequence of mounting. Products are stacked (admissible amount individually for a particular type) on spacers about 3 cm high, located strictly one under the other, or in group cassettes. The frame components are placed in the installation area (operating radius of the crane reach without changing the reach of its boom) of the crane. Changing the reach of the boom is allowed only for the transfer of floor slabs. The movement of structural components is carried out only by lifting equipment.
The slings are attached to the mounting fittings in accordance with the drawings. Manual transfer of loads weighing up to 50 kg is allowed (drag - prohibited) at a distance of up to 30 m. Before assembly, it is allowed to lay out the same type components (columns, beams, etc.) on gaskets in order to inspect the condition of the reinforcement outlets. Such structural releases are protected from damage; it is unacceptable to attach slings to them.
Raising and lowering loads is carried out with a static hover above the break-off / installation point at a height of 300 mm. The spatial position of the products in this case must correspond to the design position when installed in the building structure (examples - panels, columns, flights of stairs, etc.). To improve orientation in the air, one or two guys attached to them are used. Hardware at the construction site is placed sorted in a special room.
Concrete works
The components of concrete compositions are dosed by weight. The volume of water in the solution is a guideline for the volume of modifying additives that change the properties of concrete (frost resistance, plasticity, fluidity, hydrophobicity, etc.). The proportions of the components are determined with respect to all batches (grades) of cement and aggregates by and . It is not allowed to increase the workability of concrete by adding water to the mixed mix. The requirements established by SNiP 3.03.01-87 for the formation of solutions are shown in Table 1.
Places of laying (forms), their seams and surfaces are cleaned of seasonal sedimentary moisture, dirt, debris, oil and grease stains, cement dust film, then washed under pressure and dried. The size of aggregate grain fractions should not exceed 1/3 of the size of the weld section at the narrowest point, should not exceed 3/4 of the minimum distance between the reinforcing bars. The concrete is poured in layers. Vibrotamper is performed by immersing the tool to a depth of 50 - 100 mm.
Its support on embedded parts, formwork and reinforcement is unacceptable. The step of movement on the surface is 1.5 of the range of the equipment. Surface action models are rearranged with 100 mm overlap of compaction areas. Subsequent layers of the solution are poured after the strength of the previous layer is 1.5 MPa.
Concrete processing
After that, it is covered with a cement screed 20 - 30 mm high, which is covered with a waterproofing compound. is subjected to the formation of technological holes and openings, anti-deformation seams (a set of strength indicators from 50% and above). It is preferable to use diamond cutting tools (they exclude vibration loads) with forced heat removal from the working area.
Reinforcement
It is carried out by installing factory-made flat reinforcing meshes with longitudinal and transverse components in the formwork. Such reinforcement groups long rods and keeps transverse rods from deforming. Volumetric connection of layers of structural reinforcement inside the formwork and working reinforcement of different products is carried out by knitting wire, welding, screw couplings, crimp sleeves, etc. Before pouring, the quality of mounting the metal is checked, the mold is freed from debris, scale.
The reinforcing structure should be 20-30 mm high on all sides. The pouring of the solution is accompanied by sealing with a bayonet and a vibrotamper. (the ratio of the sum of the cross-sectional areas of the reinforcing metal to the cross-sectional area of \u200b\u200bthe structure) of the lower columns of the building is set at least 2.01%, the upper ones - 0.79%. Metal can fill a concrete structure by no more than 0.1%.
Installation of columns. Reinforced concrete columns, depending on their weight and length, supply conditions, characteristics of cranes, are lifted by translational movement of the column by a crane, rotation of the column around the base and translational movement of the crane, rotation of the column and crane boom. Heavy and tall columns are lifted by moving the lower end on a trolley or turning around the base on a steel shoe.
For the installation of light columns, friction grips are used (Fig. 6.15). After the column is installed, the grip falls down under the action of gravity and opens.
It is also possible to sling the column "in the girth" with a conventional universal sling. Heavy columns are captured by traverses with a double sling hooked to mounting loops above the center of gravity.
Typical prefabricated reinforced concrete columns of one-story industrial buildings weighing 1.8. 26.4 tons and a height of 3.8. 19.35 m, are mounted in glass-type foundations using TsNIIOMTP wedge liners (Fig. 6.23, b).
Prior to the installation of columns in the foundations, it is necessary: to accept the foundations according to the act (with the application of the executive scheme); close the glasses of the foundations and fill the sinuses of the foundations; deliver to the installation area the necessary installation tools, as well as fixtures and tools, according to the standard set; put the risks of the center axes on the upper faces of the foundations and the side faces of the columns.
The "mounting horizon" is arranged. With the help of a level, the “mounting horizon” mark is placed inside the foundation cups, i.e. bottom of the installed column. According to these marks, the bottom of the foundation glass is poured (mortar grade M50, fine-grained concrete of class B7.5). For heavy columns, the “mounting horizon” is arranged from a package of reinforced cement gaskets, because such columns during installation “squeeze out” partially the gravy, which lowers the design mark of the column (Fig. 6.25, a). Linings with a size of 100 × 100 mm, a thickness of 10, 20, 30 mm from a solution of brand 100 are reinforced with a mesh with cells 10>; 10 mm from steel wire with a diameter of 1.0 mm.
Slinging of columns is carried out for mounting loops or a special rod passed into the hole of the column. In the absence of mounting loops or special holes, the columns are slinged with a friction grip or a noose loop for the places indicated by the manufacturer. To ensure the safety of the rope, steel linings are installed under the ribs of the columns at the junction of the rope.
Temporary fastening and alignment of columns is carried out with wooden or steel wedges, as well as with the help of wedge liners. They allow you to move the bottom of the column "left-right" and "forward-backward". The verticality of the column is regulated by the boom of the assembly crane at the top of the column.
The alignment of the axes of the column and the center axes on the foundation is controlled by two mutually perpendicular axes. The verticality of the columns is checked using two theodolites or a theodolite and a plumb line along two staking axes. In this case, one theodolite must be installed along the mounting axis and the installation of columns is carried out in the direction "toward" (to the theodolite). The second theodolite is transverse and is rearranged for each column. Elevations of support platforms for crane beams and truss structures, as well as the bottom of foundation cups are controlled by the method of geometric leveling.
The slinging of the installed columns is carried out only after they are fixed in the glasses of the foundations with wooden or steel wedges from four sides.
Columns with a height of more than 12.0 m must be additionally fastened with steel rope braces in a plane of less rigidity.
Execution of a working joint. It should be remembered that the design vertical forces of the reinforced concrete column are transferred to the foundation, not only by the end (lower surface) “pushing through” the foundation, but also by the side faces connected to the walls of the foundation glass by monolithic concrete of class B15. IN 20.
The joint cavity is blown with compressed air from a mobile compressor and wetted (glass walls and the lower part of the column). The cavity is filled with a rigid concrete mixture and compacted with a slotted vibrator (deep vibrator with a steel bar nozzle with a diameter of 15.20.0 mm). Within three hours, the movement of heavy vehicles (cranes, tractors, loaded vehicles, etc.) is not allowed closer than 20.0 m from the monolithic joints.
In the design areas (in the middle of the temperature block), to ensure the longitudinal stability of the building, vertical connections are installed between the frame columns. Vertical connections are made of rolled steel (corners or channels): cross, with a column spacing of 6.0 m: portal, with a column spacing of 12.0 m. After installation, the installation of the following structures is allowed - crane beams or trusses.
Installation of crane beams. Reinforced concrete crane beams are T-shaped elements 6.0 m long with a height of 800 mm and weighing up to 3.0 tons and 12.0 m long with a height of 1400 mm and weighing up to 8.0 tons, which are supported on the consoles of the columns.
On the supporting consoles of the columns, the risks of the center axes of the crane beams are applied. On the beams themselves, central axial risks are applied on the supporting parts. The beams are slinged with a two-branch sling "in the girth" (with liners for the rope). Beams 12.0 m long are lifted using a traverse (Fig. 6.26).
The "mounting horizon" along the supporting consoles of the columns is arranged as follows. Having determined the highest mark according to the scheme, all other reference points, the level of which differs by more than 2.0 mm, are raised using a package of steel gaskets 1.0 mm thick.
The beams installed on the console of the columns are temporarily fixed with a conductor, with the help of which the ends of the beam are moved when it is aligned in the plan. The alignment of the beams is carried out within the temperature block or span using geodetic instruments: in height - by the method of geometric leveling; in plan - by the method of lateral leveling using a theodolite or by a plumb line with steel wire stretched 0.8-1.0 m above the level of crane beams along the axis of the crane runway and fixed on brackets welded to the column.
The distances between the axes of the installed beams are checked with a comparated tape measure with a double displacement of the measuring drive, adjusted for the sag of the tape measure and temperature. Permissible average error during geodetic control should not exceed 20% of the permissible deviation per controlled size.
When installing beams with crane rails already installed on them, the distance between the heads of the crane rails is measured.
Tent installation. When installing one-story industrial buildings with mobile jib cranes, it is not possible to lay floor slabs on trusses mounted throughout the building during the lateral penetration of the crane. Therefore, a complex installation of a "tent" on a cell (column spacing) is carried out: truss trusses, truss trusses, truss trusses, roof slabs.
The “mounting the tent” flow is carried out by a mobile crane with a lifting capacity of 25-63 tons with the appropriate mounting equipment, running along the axis of the span and performing the installation “on itself”. With a step of bearing columns of 6 m, cranes with ordinary booms or booms with a jib are used; with a column spacing of 12 m, installation is carried out with booms with a jib or tower-jib equipment.
During the installation of the tent, the first truss installed in the design position is fixed with three pairs of braces (in the center and at the edges of the truss), the second and subsequent trusses are fastened to the previous one using inventory struts of a fixed length (6 or 12 m) (Fig. 6.25).
On the heads of the columns, the risks of the design axes are applied. The central risks are applied to the supporting parts of the trusses. On the top of the farm, a railing is arranged. Guys from a hemp rope of the required length are attached to the ends of the truss for turning and pointing the supporting parts of the truss at the head of the column. In the center of the upper chord, a mounting spacer with a length of 6.0 or 12.0 m (according to the column spacing) is attached.
"Mounting horizon" in this case is not satisfied, because. the accumulation of errors in height has stopped, and correction of errors in the elevations of the tops of the columns is not required.
Cover beams and trusses with a span of more than 12.0 m are lifted by traverses, the length of which depends on the length of the structure being lifted.
The slinging of truss trusses, depending on the span, is carried out for two, three or four points. The farm is captured in the nodes of the upper belt.
The first truss truss (without spacers) is lifted by a traverse of the appropriate length and guided to the tops of the columns. Alignment of the supporting parts of the farm (combination of axial marks) is carried out "on weight". Correction of the situation - lifting with a crane and re-pointing.
Temporary fastening of the first truss is carried out by three pairs of braces made of steel ropes fixed on the ground by anchors (anchors) (Fig. 6.27). The truss is aligned vertically with a plumb line. On the supporting parts, a welded assembly joint is made.
The second roof truss and all subsequent trusses are similarly placed on the column heads and fixed with a mounting spacer to the first truss (to the previous one). Mounting joints are made on the supports.
Next, the coating slabs are mounted on the cell (two trusses installed on the columns). The 6.0 m long slab is lifted with a four-branch sling; with a length of 12.0 m, various traverses are used. After installation, the plates are welded at three points (one point is not available, Fig. 6.27, d) immediately with a working seam, because connection points are successively closed by subsequent plates.
Installation of external wall fencing. After the installation of the building frame or part of it, wall panels begin to be mounted. In most cases, wall fencing is mounted by an independent flow after the installation of the building frame and cover is completed.
Design decisions regulate the layout of the outer and end walls, as well as the layout of panels in the upper part of the walls (with parapets and cornices). Methods for attaching panels to columns, as well as filling the joints between panels, are shown in fig. 6.25.
Prior to installation, the wall panels must be stored at the working parking lots in the area of the installation crane. In this case, there can be three options: for buildings of small height, the cassette is located between the mounting crane and the wall to be mounted (the volume of the cassette provides a sufficient number of panels for building a wall for the entire height of the building); the mounting crane is located between the cassette and the wall to be mounted (the volume of the cassette ensures that the wall is installed to the entire height of the building); if the wall is provided with two cassettes, the mounting crane is located between these cassettes.
If the wall height consists of more than 12 panels, installation is carried out in two crane penetrations. At the same time, installers align and fasten the panels to be installed from work platforms located on the inside of the building. If it is possible to travel inside the building, it is advisable to use two car-based lifts as installers' workplaces. In the absence of lifts, various scaffolds and self-elevating cradles can be used as working platforms.
The progressive technology of mounting the outer walls of one-story industrial buildings is based on the use of specialized tower-jib equipment developed for RDK-25 jib cranes; E-10011D; E-1254, as well as for tower cranes of the BKSM-3-5-8 type (Fig. 6.28).
The main technological features of the use of specialized equipment for jib cranes are: combining the functions of a crane with an assembly site; the ability to move the mounting platform up and down the tower, as well as horizontally - from the tower to the wall and back; placement of wall panels in cassettes installed between the crane and the wall being mounted; the width of the installation area along the perimeter of the building when the crane is operating with specialized equipment is about 8.5 m.
The slewing part of the jib cranes can be rotated when the mounting platform is in the lower position at a minimum reach. In other positions of the mounting platform, the rotary part of the crane is automatically blocked.
Progressive technology of installation of external wall fencing reduces costs by 1.5-2 times.
The wall panel is lifted with a crane at the maximum distance of the mounting platform from the wall. After the panel has been delivered to the installation site, the mounting platform, together with the installers, is fed close to the wall (the supply stops automatically after the stoppers hit the columns).
Installers located on the site provide guidance and installation of the panel in the design position, its alignment, temporary and final fastening by electric welding of embedded parts.
Sealing of horizontal and vertical seams is carried out immediately, simultaneously with installation. When installing wall panels with a conventional jib crane without the described special equipment, the grouting is separated into a separate stream and is performed together with the “finishing” stream. In this case, work is carried out from outdoor adjustable, mobile and self-propelled scaffolding; hanging cradles.
To inject sealing mastics and solutions into the joint cavity, hydraulic, pneumatic and mechanical superchargers, injectors, mortar syringes are used.
Simultaneously with the installation of wall panels, steel elements of light openings (imposts, bindings) are installed.
Installation of reinforced concrete structures of one-story industrial buildings
Installation of reinforced concrete structures of one-story industrial buildings Installation of columns. Reinforced concrete columns, depending on their mass and length, supply conditions, characteristics of cranes, lift
LECTURE 12. Installation of structures of industrial and civil buildings.
Features of the installation of buildings and structures
Installation methods are characterized by a complex of organizational and technological features.
Main organizational features:
direction of development of the work front;
sequence of assembly operations;
the degree of enlargement of mounting elements;
division of the course of installation work (into queues, stages) and structures (into grips, nodes, etc.).
Technological features: features of performing individual operations for gripping (slinging), aiming, orienting and installing mounting elements in the design position, their fastening, anti-corrosion protection, etc.
Installation of one-story industrial buildings. For one-story industrial buildings of light type with a reinforced concrete frame, a separate method of mounting structures is rational.
One-story industrial buildings of a heavy type are mounted mainly by an integrated method.
For industrial buildings with an area of more than 30 thousand m 2 with metal structures of the coating, it is economically and technologically justified to use the conveyor method of large-block assembly.
Installation of shells of domed, vaulted, structural and other coatings:
ground assembly in conductors with subsequent lifting of the shell structure to the design position;
assembly on design marks.
The choice of the mounting method for large-span buildings is due to the fact that their plan dimensions exceed the range of mounting cranes, and some mounting elements (frame elements, arches, etc.), due to their large masses and dimensions, have to be mounted in parts using temporary mounting supports, or lifted in in one-piece assembly form, using the paired work of erection cranes or lifts.
During the installation of structures, it is necessary to follow the technological sequence that ensures the stability and geometric invariability of the mounted structures.
When erecting one-story buildings, the crane movement paths and mounting positions must be chosen so that the largest possible number of elements can be mounted by a crane at each parking lot. So, for example, with a span of 12 m and a column spacing of 6 m, two, four or six mounting elements can be mounted by a crane moving in the middle of the span. With a span of 18 and 24 m, the crane can move along each mounted row and mount up to four elements.
The installation of precast concrete columns is carried out using various grips and slings. In cases where the installation is carried out from vehicles or the column has insufficient bending strength, appropriate balancing devices are used to transfer the structures to a vertical position by weight. In this case, slinging is carried out at two or more points. Installation, alignment and fixing of columns is carried out using wedges, braces, conductors.
Installation of roof beams and trusses is carried out using traverses. Slinging of reinforced concrete trusses in order to avoid loss of their stability is carried out at two, three or four points. Before lifting, braces are hung on the trusses (for aiming it), inventory spacers and mounting platforms. To ensure stability and geometric invariability, the first installed truss> or beam should be braced with braces made of steel Kai tta, and subsequent struts attached with clamps to the upper chords of trusses (beams), or special conductors (Fig. 10.3). Usually, for trusses with a span of 18 m, one spacer is used, for spans of 24 and 30 m, two.
If there are no special instructions in the project for the production of works, it is recommended to lay the coating slabs according to the markings on the upper chords of trusses (beams) in the following order: along metal trusses or lanterns - starting from the middle of the span with a symmetrical load; on reinforced concrete beams or trusses with roofless roofs - from one edge of the roof to the other: in spans adjacent to previously installed ones - from the installed roof to the free end; on reinforced concrete trusses with a lantern - from the edge of the coating to the lantern. The embedded parts of each slab in at least three support nodes must be welded to the embedded parts of the upper chord of the truss (beam); the first plate is welded at four points.
Installation of wall panels begins after the final fixing of all elements of the building frame.
Installation of multi-storey buildings. Multi-storey buildings are mounted with one or more tower cranes, placed in such a way as to exclude "dead" areas outside the service areas.
When installing frameless panel buildings, the order in which the panels are installed is determined by the project for the production of works. Installation is carried out using individual or group mounting equipment, while the edges of the element or the risks on it must be combined with the risks taken out from the center axes.
Rice. 10.3. Location of attachments and temporary fastening of trusses with inventory
spacers during the installation of coating structures: a - truss attachments;
b - installation diagram of spacers; one- ladder; 2 - hinged ladder;
3 - hinged platforms; 4- safety rope; 5- inventory spacers;
6 - the position of the struts during the lifting of the truss; 7 - clamp; 8- rope;
9 - mounted part of the span; 10- clamp; 11 - full swivel joint
The project for the production of works provides for the sequence of installation of panels, taking into account the following conditions:
Installation begins with the creation of rigid nodes that ensure the spatial immutability of structures. These include the outer corners and stairwells of the building. Typically, installation begins at the outer corners of the building, with the corner panel of the end wall usually placed first.
The installation of prefabricated elements is carried out "on the crane", i.e. starts from the wall farthest from the tap. In this case, the visual connection of the crane operator with the installation site is provided, safer working conditions are created, since the panels do not have to be moved over previously delivered ones. If there are two construction cranes, installation starts from the outer corners of the building closest to each installation crane.
The outer wall panel should not be installed between the previously installed ones. This may compromise the stability of the panels or damage them.
Exterior wall panels, load-bearing interior wall panels and balcony slabs are installed during daylight hours.
Installation of internal wall panels is carried out using individual mounting devices, group equipment, as well as special parts embedded in the body of the panel during manufacture (spatial self-fixation method).
The panel, adjusted in plan, is temporarily attached with struts to the floor slabs, the internal panels can be temporarily fastened with universal racks, clamps, ties.
At installation of frame-panel buildings the installation of columns in the design position is usually carried out by a limited free method, using a hinged frame indicator, or by a free method, using a single or group conductor. Temporarily the columns are fixed with wedges, braces, portable jacks, conductors or frame-hinged indicators. The height of the columns determines the height of the tier: with columns on one floor, the height of the tier is one floor; with columns on two floors - the height of the tier is two floors, etc. Installation of the next tier is carried out after installation, welding and embedding of crossbars and floor slabs of the underlying tier.
The installation of the crossbars is started after the concrete reaches the joint of the columns with the foundation of at least 50% of the design strength in summer and 100% in winter. The location of the crossbars can be longitudinal and transverse. The crossbars must be centered along the axes of the columns, observing the design dimensions of their support on the consoles of the columns.
Installation of the ceiling begins with the installation of spacer (bonded) slabs, first the lower and then the upper floor. The slab is delivered to the installation site in an inclined position using a special sling. The laid plates are welded at four corners to the crossbar saws. Ordinary floor slabs are laid similarly to expansion slabs.
After the installation of floor slabs and floor slabs, the installation of wall panels begins. Waist panels, based on wall or floor slabs, are temporarily attached either to a column or to a slab with special clamps with struts or ties. Wall panels are attached with struts to floor slabs or to the underlying belt panel with clamps with folding clamps.
Simultaneously with the installation of the panels close up the joints.
Installation of buildings from three-dimensional blocks begins after the complete completion of all works of the zero cycle, from vehicles. Installation of additional elements is carried out from the on-site warehouse.
For blocks with linear support, wooden beacons are installed embedded in the cement-sand mortar of the block bed. For blocks with point support, support platforms are made of metal plates, recruited to the desired height, and a bed of cement-and-sand mortar is made around these support platforms.
Slinging of blocks is carried out with four-branch slings or special balancing traverses with manual or automatic adjustment, which allow you to level the position of the block if its outer wall is thicker and more massive than its inner one.
Blocks are mounted starting from the middle of the floor to the ends, which reduces the accumulation of possible errors arising from inaccuracies in the manufacture and installation of blocks. The gap in height is allowed no more than one floor.
Installation of steel structures. Metal columns rest: directly on the foundation with a concreted and worn leveled surface; on steel support beams concreted into the foundation; on steel plates with a planed top surface. For support on steel plates, it is necessary to provide for the processing of the base plates and soles of the column shoes by milling at the factory. In this case, the column is installed without alignment. The alignment-free installation of columns makes it possible to reduce the labor intensity of installation by 30%.
The columns are fixed to the foundation with anchor bolts, onto which the nuts are tightly screwed. When mounting columns up to 15 m high, in addition to anchor bolts, they are fixed in the direction of least rigidity with at least two braces. With a column height of more than 15 m, the method of their fastening is determined by calculation.
Installation of crane beams, truss and roof trusses is carried out after alignment and final fixing of the columns and ties, ensuring the rigidity of their position.
Block installation - installation of structures previously enlarged into flat or spatial blocks. It reduces the labor intensity and duration of the construction of large industrial facilities. An example of a flat block is half-timbered columns connected by girders and ties, a spatial block is a block of two trusses with girders and ties. An indispensable requirement for a spatial block is its geometric immutability. There are mounting blocks of incomplete and full factory readiness. The latter are a finished part of a building or structure that does not require additional construction and installation work after its installation in the design position.
The assembly of blocks of incomplete factory readiness (for example, with spatial dimensions of 12x24, 12x36 m, etc.) is assembled on a conveyor line, which is a rail track located in the immediate vicinity of the object being mounted with trolleys-conductors moving along it from post to post, on which assembly is carried out. The design of the block should make it possible to mount coatings according to the “block to block” system.
The finished block is transported on a conductor trolley to the installation site and, using powerful cranes or special installation cranes mounted on overhead cranes, is installed in the design position.
This method (conveyor assembly and block assembly) is economically feasible in the construction of one-story industrial buildings with an area of at least 30-50 thousand m 2.
On the principle of block installation, the complete-block method of construction is based. The essence of the method is that at the design stage, objects are divided into large-sized, but transportable, structurally complete and equipped with process equipment assembly blocks in order to erect and commission capacities in the shortest possible time and with minimal labor costs. Blocks are manufactured in the factory and delivered to the site by road trains. Installation consists in installing the blocks in the design position, processing joints and connecting communications. From superblocks weighing 200-350 tons and more, various industrial buildings of almost any length with a height of 5.2 and 6.4 m with spans of 12 and 24 m can be mounted.
The block method of installation allows you to transfer the volume of construction and installation work from the construction site to industrial production as much as possible, drastically reduce post-installation processes and ultimately reduce the duration and cost of construction.
Safety precautions for installation work
The requirements of the rules for the safe conduct of installation work should be taken into account already at the initial stage of designing an object through the use of rational design solutions and structures, for example, large blocks of coatings with their ground assembly, technologically assembled elements that ensure their assembly with minimal manual labor and time, etc. .d.
Measures for the safe conduct of installation work should be provided for at the stage of development of the project for the production of works - through the use of such installation methods and such a technological sequence of installation operations that would provide the most convenient access for cranes to installation positions, as well as the rigidity and stability of those mounted earlier: mounted structures.
test questions
What installation methods are distinguished depending on the accepted sequence of installation of building frame elements?
What methods are distinguished depending on the direction of installation of buildings?
What are the basic requirements for transporting building structures?
What are the basic requirements for the storage of building structures (their position, stack sizes, etc.).
How is the pre-assembly of structures made?
What are the main technical characteristics and features of cranes?
How are cranes selected?
What do you know about the purpose and variety of load handling devices?
How are one-story industrial buildings erected?
10. What are the basic conditions for safe work with cranes?
Main literature: pp 320-474, pp 306-396, pp 245-278
Additional literature: [ 10] pp. 155-252, pp. 54-152, pp. 305-336.
Installation of elements of reinforced concrete structures
Technology - Installation of building structures
Installation of prefabricated foundations
The installation of prefabricated foundations is usually carried out in a separate advanced flow during the construction of the underground part of the building. The breakdown of the installation sites of the foundations is carried out using longitudinal and transverse axes, fixed with a wire.
When installing foundations for columns, the position of the axes is transferred to the bottom of the pit with a plumb line, fixing them with pins or pegs hammered into the ground. On glass-type foundations, the middle of the side faces of the glass is determined and axial risks are applied to the upper face. When lowering the block on the base, the position of the block is controlled by risks.
The installation of the glass-type foundation must be carried out immediately in the design position in order to avoid disturbing the surface layer of the base. The position of the foundation block in height is verified using a level, controlling the level of the bottom of the glass. The position of the block in the plan is checked with the slings not removed by combining the marks (installation and marking axes) along two mutually perpendicular axes, a small deviation is eliminated by moving the block with a crowbar.
Upon completion of the installation of the foundation blocks, a geodetic survey of their position is carried out - altitudinal and in plan. Based on the results of the survey, an executive diagram is drawn up, on which possible displacements of the blocks are indicated.
Foundation installation:
1 - caterpillar crane; 2 - the position of the block of foundations before lifting; 3 - foundation block during installation
Permissible deviations of the installed cup-type foundation blocks from the design position: the displacement of the axes of the blocks relative to the center axes is not more than ± 10 mm, the deviation of the bottom marks of the cups is 20 mm.
Installation of columns
The installation of glass-type foundations and, in general, the construction of structures of the underground part of the building are classified as zero-cycle works and are carried out by an independent assembly stream. The above-ground part of the building is usually mounted by a mixed method, when columns are mounted and wall panels are mounted by independent flows, and crane, under-rafter and truss trusses are installed in a complex, and roofing panels are laid.
For one-story industrial buildings, a range of prefabricated reinforced concrete columns up to 19.35 m high and weighing up to 26.4 tons, mounted in glass-type foundations, has been developed.
Before installing columns, you must:
Fill up the sinuses of the foundations;
Apply on four faces at the level of the upper plane of the foundations the risks of the installation axes;
Close the glasses of the foundations with shields to protect them from pollution;
Arrange roads for the passage of the assembly crane and cars;
Prepare areas for storing columns at the place of their installation;
Deliver to the installation area the necessary installation tools, fixtures and tools;
Check the position of all embedded parts of the columns;
Apply the risks of the installation axes on the side faces of the columns.
The columns are preliminarily laid out at the installation sites on wooden linings with a thickness of at least 25 mm. The layout of the columns is carried out in such a way that the crane from the assembly site can install them in the design position without changing the boom reach. Before installation, each column must be inspected so that it does not have deformations, damage, cracks, shells, chips, exposed reinforcement, concrete sagging. It is necessary to check the geometric dimensions of the column, the presence of a mounting hole, the correct installation of steel embedded parts.
Before or simultaneously with slinging, a column with a height of more than 12 m is built up with stairs, hinged cradles, braces.
Slinging columns carried out for the mounting loops, for the mounting rod, passed into a special hole in the column. Friction grips or various self-balancing traverses are widely used, allowing the column to be lowered vertically onto the foundation. All of them must provide remote slinging, eliminating the need for a worker to rise to the slinging site after installing the column in the foundation sleeve. The columns are lowered into the foundation glass with the help of a mounting crane on reinforced concrete pads or on a leveling layer of concrete mix.
Alignment and temporary fixing columns installed in the foundations are carried out using a set of mounting equipment. The design position of the bottom of the column at the bottom of the foundation glass, temporary fastening and vertical alignment of the columns are carried out using wedge liners. The stability of the columns after installation is provided with temporary fasteners, most often with conductors or wedge liners. Vertical alignment and correction of columns is carried out using jacks; in this case, the deviation from the vertical and the displacement of the axes of the columns in the lower section should not exceed the standard values.
Columns up to 12 m high are usually fixed in foundation glasses only with the help of wedge liners; for higher columns, conductors and braces are additionally used. The slinging of the installed columns should be carried out after they are securely fixed in the foundation glasses with wedge liners, and, if necessary, with braces.
The inventory wedge insert consists of a body with a nut and a handle, a screw with a boss and a wedge suspended on a hinge. Wedge inserts are installed in the gaps between the faces of the column and the walls of the foundation glass. For gaps greater than 90 mm, additional inserts are used. When the screw is rotated with a key, under the action of the boss, the wedge moves in the body on a hinge, as a result, a spreading force is created between the wedge and the body of the glass. Before sealing the joint between the column and the foundation with a concrete mixture, a fence is installed on the wedge liner, which is removed from the glass immediately after compaction of the rigid concrete mixture or after the start of setting with conventional mixtures.
Conductors of various types are used for temporary fixing of columns. The conditions for the use of various types of conductors, the procedure for performing work on the installation and alignment of columns with their use is specified in the project for the production of works.
After the alignment of the columns, their fixing in the design position is carried out by concreting the joints with a concrete mix on quick-hardening non-shrinking cement using a pneumatic blower. The wedge inserts are removed only after the concrete has acquired the joint strength specified in the project for the production of works or when the concrete reaches 50% of the design strength.
When installing columns, it is necessary to check the level of the bottom of the foundation glass, the alignment of the risks on the edge in the lower part of the column with the alignment risk on the upper edge of the foundation, the verticality of the columns, the marks of the crane console and the column head. The alignment of the axes of the column and the staking axes must be controlled along two axes, the verticality of the column must be ensured using one or two theodolites along the two staking axes or a zenith device using the vertical design method. Elevations of support platforms for crane beams and trusses are controlled by the method of geometric leveling.
Installation of foundations begins with a breakdown of the axes of the structure and their binding to the terrain. The breakdown of axes on the ground is carried out by surveyors. The design mark of the base of the foundation is determined by a level. After that, the axes of the structure are transferred to the bottom of the pit. The axes are fixed on cast-offs.
For strip foundations, two structural elements are mainly used: a block-cushion of a trapezoidal or rectangular shape, laid in the base of the foundation, and wall blocks or panels from which the foundation wall is erected. The basis for strip foundations is sand bedding, which is laid on the ground protected or compacted with crushed stone at the bottom of the pit or trench. The installation of strip foundations begins with the laying of lighthouse blocks, which are aligned and installed in strict accordance with the axes of the walls of the structure. Beacon blocks are installed at a distance of no more than 20 m from each other. Corner blocks and intersection blocks are always beacon blocks. A mooring cord is fixed along the inner, and sometimes along the outer edge of the lighthouse blocks. At a height of 20-30 cm from the installation site, the block is oriented and lowered to the design position. Permissible deviations from the design position during the installation of strip foundations from precast concrete blocks should be no more than (mm):
Cushion blocks are laid one close to the other or (with good bearing capacity of the base) with gaps that can reach up to 40-50 cm. Cushion blocks are laid around the entire perimeter of the building or within one grip. For the passage of pipelines and cable glands during the continuous laying of pillow blocks, special mounting holes are left.
Blocks or panels of the foundation walls are installed on the design marks, filling the joints with cement mortar. Basement panels are usually welded to embedded elements in pillow blocks. Wall elements during installation are verified both relative to the longitudinal axis and vertical. After the installation of all blocks along the upper edge of the wall, a leveling layer (mounting horizon) is made of cement mortar, the surface of which is brought to the design mark. The installation work of the zero cycle is completed by the construction of the basement and ceiling above the basement or underground. Strip foundations are usually mounted with a crane standing at the level of the layout, and not in the pit.
Installation of prefabricated reinforced concrete foundations begins with a slab
Installation of prefabricated reinforced concrete foundations begins with a slab. After installing it in the design position, a bed of cement mortar is arranged on the slab, on which a block glass is installed. Embedded parts are used to connect the glass to the plate. After welding, the embedded parts are protected with an anti-corrosion coating. The installation of the foundations of industrial buildings, made in the form of a single block, is carried out using a crane. The guidance of the foundation blocks to the design position is carried out on weight, after which the block is lowered to the prepared place and adjusted according to the risks of the axes, combining them with the pins or risks that fixed the position of the axes on the base. If the installation is incorrect, lift the unit, correct the base and repeat the installation procedure again. The correctness of the installation of the foundations vertically is checked by a level.
Reinforced concrete columns are mounted as follows
Before installation, check the position of the transverse and longitudinal axes of the foundations and the marks of the supporting surfaces of the foundations, the bottom of the glasses, the dimensions and position of the anchor bolts. Before installation, axial risks are applied to the columns along four faces at the top and at the level of the top of the foundations, and for columns intended for laying crane beams along them, in addition, the risks of the beam axes are applied to the consoles. Columns of industrial buildings are mounted by first laying them out at the place of installation, or directly from vehicles. The columns are laid out in such a way that during the installation process it is necessary to do a minimum of movement and various auxiliary works and there is free access for inspection, attachment of equipment and slinging. The columns in the installation area are laid out according to various schemes. With a linear layout, the columns are laid out in one line parallel to the axes of the building and the movement of the crane. This layout is performed on the condition that the length of the column is less than the step of the foundation. When laying out in ledges, the columns are placed parallel to the axis of the structure being mounted and the axis of the crane penetration. Inclined layout is used when the size of the layout area is limited; the centered layout scheme is characterized by the fact that the trajectory of rotation of the crane boom during the installation operation is a one-sided arc. The columns are laid out not flat, but in such a way that during the lifting process the bending moment from the weight of the column and equipment acts in the plane of the greatest rigidity of the column. This is especially important to consider when installing two-branch columns. When laying out, you should take into account the way in which the installation is to be carried out. Rectangular and two-branch columns are more convenient to lift from a position on edge. Since the column can enter the site in a flat position, the first operation during installation is to tilt it on edge. After the layout, the columns are inspected, checking their integrity and dimensions. At the same time, the dimensions and depth of the glass under the column are checked. Then the column is lined with stairs, fixtures, braces, etc.
The conditions for ensuring the correct position of the column during installation are provided for in the installation project. When lifting columns by turning, the lower end of the column is usually fixed in a special hinge fixed on the foundation. When lifting columns by turning with sliding, the lower end of the column is pivotally attached to a special trolley, to a skid, or equipped with a spacer and a roller. The columns are slinged with various friction grips, pin grips with local or remote slinging, and when mounting from vehicles, with balancing traverses. It should be strived to ensure that the column hangs on the crane hook in a vertical position and does not have to go up to unsling it. Friction grips are put on the column with the beam removed. After installing and fixing the beam, the column is raised. The grip holds the column due to the friction that occurs between the beams and the surface of the column when the cables are tensioned.
Holes for pin grips must be provided during the manufacture of columns. A cable is used to unsling the pin grips used to lift light columns; for slinging heavy columns, the grips are equipped with electric motors. From vehicles, columns are mounted by turning on weight. To reduce the length of the crane boom during mass installation of columns, booms equipped with a forked head are used. Lifting the column (transferring it from a horizontal to a vertical position) consists of three successive operations:
transfer of the column from a horizontal position to a vertical one; supply of the column to the foundation in a raised position; lowering the column to the foundation.
The column is lifted in one of the following ways:
the crane moves in the direction from the top of the column to its base and at the same time raises the hook. The column gradually rotates around the support rib. To prevent slipping, the shoe is reinforced with a brace. The movement of the crane and the lifting of the hook are performed in such a way that the cargo chain hoist is always in a vertical position; the crane is stationary. Simultaneously with the lifting of the hook, the shoe of the column mounted on the trolley, or the guide rail track lubricated with grease, moves in the direction of the vertical. These two methods are mainly used when lifting heavy columns and using such cranes that cannot move with a suspended load; the crane is installed in such a way that the slinging point and the lower end of the column are at equal boom outreaches. The column is lifted by turning the boom while simultaneously operating the cargo chain hoist, which must always be vertical. The top of the column and the place of slinging describe spatial curves. This method of lifting is mainly used when erecting light and medium columns with jib cranes.
After lifting and installing the column in place, without releasing the crane hook, they begin to align their position. Lightweight reinforced concrete columns are aligned using mounting crowbars and wedges placed in the foundation glass, and special mechanical wedges. The correct position of the columns in the plan is achieved by combining the axial risks on the column with the axial risks on the foundation. Checking the position of the columns is carried out with a theodolite and a level.
Immediately before the installation of the columns, a leveling layer is laid in the glass-type foundations, filling the gap between the bottom of the glass and the lower end of the column. The preparation is made of rigid concrete, laid in a layer, the thickness of which is determined by measuring in kind the mark of the bottom of the glass and the length of the column. After installation, the column compresses the fresh preparation with its weight; in this case, a uniform pressure transfer to the bottom of the glass is achieved. Another way to fix columns is as follows. On the foundation, the bottom of which is not concreted to the design mark by 5-6 cm, install, align and securely fix the support frame. To create the surface of the base, a forming device is used, which has special stamps and a vibrator. Then, concrete is placed on the bottom of the glass and the forming device is lowered, directing its bushings to the fingers of the support frame, then the vibrator is turned on. Lowering under its own weight to the stop, the stamp of the forming device squeezes out in the concrete of the gravy at the required mark, prints of a certain shape, strictly oriented relative to the axes of the foundation; excess concrete is squeezed upwards, after which the forming device is removed and transferred to the next foundations. The use of this method requires the manufacture of columns with increased accuracy.
Short columns of multistory buildings can be raftered close to their top. Slinging of reinforced concrete columns of one-story buildings at the upper end, as a rule, cannot be carried out, since the resistance to its bending may be insufficient. In most cases, the slinging of such columns is carried out at the level of the crane console. In this case, during the turn, the lower end of the column rests on the ground and bends like a single-cantilever beam. The raised column must be vertical. To do this, you need to hang it from a point located on a vertical line that passes through the center of gravity of the column. For lifting, a traverse with grips or slings is used, covering the column from both sides. If the bending strength of the column is insufficient, increase the number of suspension points.
Methods for temporarily fixing columns
The methods of temporary fixing of the columns after installation in the design position depend on the design of the support of the columns and their dimensions. Columns installed on glass-type foundations must be monolithic immediately after installation. Before the monolithic concrete acquires 70% of the design strength, subsequent elements cannot be installed on the columns, except for mounting ties and spacers that ensure the stability of the columns along the row. Columns up to 12 m high in foundation glasses are temporarily fixed with wedges and conductors. Wooden (from hardwood), concrete and welded wedges are used; depending on the depth of the foundation glass, the wedges should be 25-30 cm long with a slope of no more than 1/10 (the length of the wedges is approximately taken as half the depth of the glass). At the faces of columns with a width of up to 400 mm, one wedge is placed, at the faces of a greater width - at least two. Wooden wedges should only be used for small jobs as they make joints difficult to seal and difficult to remove. Wedges are used not only to pinch the column in the sleeve, but also to slightly shift it or turn it in plan if it is necessary to point it at the center axes. Rigid conductors are used for temporary fixing of columns. Temporary fastening of columns with a height of more than 12 m with conductors is not enough; they are additionally secured with braces in the plane of the greatest flexibility of the columns. Columns over 18 m high are secured with four braces. These devices must provide both stability along and across the row. The first two columns are fastened crosswise with braces, the next - with crane beams. Reinforced concrete columns of frame buildings are fixed by welding, as a rule, after the installation of crossbars and welding of embedded parts of columns and crossbars. Installation of crane beams is carried out after installation, alignment and final fixing of the columns. Installation begins after the concrete at the junction between the column and the walls of the foundation gains at least 70% of the design strength (exceptions to this rule are specifically stipulated in the project for the production of works, where at the same time measures are indicated to ensure the stability of the columns during the installation of crane beams and other elements). Before installation on the ground, the condition of the structures is inspected and the joints are prepared. The beams are slinged with ordinary slings for mounting loops or in two places “for a noose” with universal strapping slings with their suspension to a traverse, the size of which is selected depending on the length of the beams. The lifting of crane beams due to their large length (6-12 m) is most often carried out using special or universal traverses or two-branch slings equipped with safety corners. When choosing a grip of a particular design, one should pay attention to the nature of the reinforcement of the beam flange and the installation conditions. So, it is impossible to use tongs on the installation of crane beams, the shelves of which are not able to withstand the bending moment from the installation load. It is advisable to carry out the installation of crane beams with crane rails attached to them before lifting (with a beam length of 12 m). The rails are fixed temporarily; the final fixing is carried out after the installation of the beams and alignment of the position of the rail. When reconciling, the position of the beams along the longitudinal axes and the mark of the upper shelf are checked. To install the beams along the longitudinal axes, risks are applied to the column supports, and on the upper slats and ends of the beams - the risks of the middle of the wall.
In the process of reconciliation, risks are combined. The position of the crane beams during their installation is adjusted using a conventional mounting tool, and after they are laid out on the support consoles, without resorting to the mounting mechanism, using special devices. After alignment, the embedded parts are welded and the beam is unstrapped. During the installation of beams, the following deviations are allowed; displacement of the longitudinal axis of the crane beam from the center axis on the supporting surface of the column ± 5 mm; marks of the upper flanges of the beams on two adjacent columns along the row and on two columns in one transverse section of the span ± 15 mm.
Rice. 38. Installation of beams and trusses covering industrial buildings
The installation of roof beams and trusses in industrial buildings is carried out separately or combined with the installation of roof slabs (Fig. 38). When preparing the trusses for lifting, they clean and align the heads of the columns and supporting platforms of the truss trusses and put the risks of the axes. For alignment and temporary fixing of trusses, scaffolds are arranged and the necessary devices are installed on the columns. The truss installation process includes the supply of structures to the installation site, preparation for lifting the trusses, slinging, lifting and installation on supports, temporary fixing, alignment and final fixing in the design position. Trusses are installed in the design position in such a sequence that ensures the stability and geometric invariability of the mounted part of the building. Installation is usually carried out "on a crane", which successively retreats from parking lot to parking lot. Truss slinging is carried out using traverses, the slings of which are equipped with remote-controlled locks for slinging (reinforced concrete truss slinging is carried out in two, three or four points to avoid loss of stability). To ensure stability and geometric invariability, the first installed truss is fastened with steel rope braces, and the subsequent trusses are fastened with struts attached to the upper chords of the trusses with clamps, or with conductors. For trusses with a span of 18 m, one spacer is used, for spans of 24 and 30 m - two spacers, which are installed in 1/3 of the span. With a truss step of 6 m, the spacer is made of pipes, with a step of 12 m - in the form of a lattice run of light alloys. The struts are attached to the truss before lifting begins. A hemp rope is tied to the free end of the pipe, with the help of which the spacer is lifted to the previously assembled truss for attachment to the clamps installed there. The spacers are removed only after the final fixing of the trusses and the laying of the floor slabs. The first trusses in the span are fixed with guys. When installing lanterns, their structures are attached to trusses before installation and are lifted together with the truss in one go.
After temporary fixing, the lantern is installed in the design position. Trusses are verified according to the risks available on the supporting platforms of trusses and columns, combining them during the installation process. To fix the trusses in the design position, the embedded parts in each support unit are welded to the base plate, which, in turn, is welded to the embedded parts of the column head. Anchor bolt washers are welded along the contour. The first two trusses in the span must have a fence or special scaffolding for the period of installation of the floor slabs. The rafters and trusses are unstrapped only after they are finally fixed.
Installation of coating slabs is carried out in parallel with the installation of trusses or after it. The installation of the coating can be carried out according to two schemes:
longitudinal, when the plates are mounted by a crane moving along the span; transverse, when the crane moves across the spans. In this case, when selecting cranes, it is necessary to check whether the cranes can pass under the installed trusses or crane beams.
It is expedient to equip cranes with special assembly jibs during the installation of roof slabs of tall buildings. Sometimes, during the installation of roof slabs, which is carried out after the installation of trusses, it is advisable to use special roof cranes that move along the mounted slabs. Coating slabs before installation are placed in stacks located between columns, or served on vehicles directly for installation. The order and direction of installation of the plates is indicated in the project for the production of works. The sequence of mounting the plates should ensure the stability of the structure and the possibility of free access for welding the plates. The location of the first slab must be marked on the truss. In lantern coverings, slabs are usually laid from the edge of the roof to the lantern. For slinging of roof slabs, four-branch slings and balancing traverses are used, and when using heavy-duty cranes, traverses with a garland suspension of slabs are used. The laid roof slabs are welded at the corners to the steel parts of the truss structures. Plates located between the first two mounted trusses are welded at four corners; located between the second and third trusses, as well as the following ones: the first during installation - in four corners, the rest - only in three, since one of the corners of each slab (adjacent to the previously installed slabs) is inaccessible for welding. Installation of plates is recommended:
on reinforced concrete trusses with a lanternless coating - from one edge to the other; on reinforced concrete trusses with a lantern - from the edges of the coating to the lantern, and on the lantern - from one edge to the other.
The installation of the first slab at the edge of the pavement is carried out from a suspended scaffold, and subsequent slabs from the previously installed ones. The joints between the coating slabs can be sealed simultaneously with the installation or after it, if there are no special instructions in the project for the production of works.
Installation of floor panels in multi-storey buildings is carried out using the main assembly mechanism, and in brick buildings - using a crane that supplies masonry materials. To lift the floor slabs, slings or balancing type traverses are used, which make it possible to give a slight slope to the panel suspended on the crane hook. Floor panels in multi-story frame buildings are laid in the same stream with the rest of the structures or after the installation of columns, crossbars and girders within the floor or grip on the floor. The installation of floor panels is started after the erection of walls in frameless buildings and the laying and fixing of spacer plates, as well as purlins or crossbars in frame buildings. Installation begins from one of the end walls after checking the elevation of the reference plane of the top of the walls or crossbars (if necessary, they are leveled with a layer of cement mortar). The panels are lifted with a four-branch sling or a universal traverse. Room-sized panels are slinged for all mounting loops. If the panels were stored in a vertical position, then before slinging they are transferred to a horizontal position on the tilter. With a universal sling, the slab is lifted from a panel carrier or from a pyramid without a tilter. One or two first slabs are installed from mounting scaffolding tables, and the next ones from previously laid slabs. If the panels are laid on a surface leveled with a screed, then the bed is made of a plastic mortar 2-3 mm thick. When laying the panels directly on the parts, the bed is made from the usual solution. If necessary, the panels are upset by squeezing out the solution during their horizontal movements. Particular attention when installing the panel on the mortar is paid to the width of the support platform, since it is forbidden to move the laid panels in the direction perpendicular to the support structures.
The sagging panels are reinstalled, increasing the thickness of the mortar bed. The thickness of the seams between adjacent panels is determined by sighting along the seam. If the plane of the panel is curved, it is laid at the junction with walls or partitions so that the free edge is horizontal. A panel with a sagging middle is installed on a thickened bed so that the sag is divided in half between adjacent plates. In multi-story frame industrial buildings, first of all, so-called "spacer" plates are mounted, located along the longitudinal axes of the building, and panels located along the walls. The order of installation of the remaining plates can be arbitrary, if it is not dictated by the project. Unstrapping is carried out immediately after the panel is installed in the design position.
Installation of wall panels is a separate stage of installation work in industrial construction. It begins only after the completion of the installation of load-bearing structures in the structural block of the building. In frame buildings, the middle of the frame columns is most often taken as the position of the axes of the building. When installing the panel of the inner wall between the columns, from their middle, lay on the ceiling with a meter a distance equal to half the thickness of the panel plus the length of the template (usually 20-30 cm); this is done in order not to accidentally destroy the risk, for example, when making a bed. If the panels do not join the columns, then a mooring is pulled along the plane of adjacent columns, the required size is set along it, and the position of the panel plane is fixed with two risks on the ceiling, taking into account the length of the template. For panels adjacent to columns, such as stiffening walls, the marks that fix the position of the panel surfaces are applied to the column at a distance of 20-30 cm from the floor and ceiling. For the installation of panels of external walls adjacent to columns, for example, in single-story industrial buildings or multi-story buildings with blank walls in several tiers, on the columns using a tape measure along the entire height of the column, the height marks of the seams of each tier are marked with risks. In large-block and large-panel buildings, in which the walls perceive vertical constants (from the mass of the building, equipment) and operational loads, marking is performed using geodetic instruments. First, the main axes are transferred to the mounting horizon; for the walls of the basements, a cast-off is used; for subsequent floors, the method of oblique or vertical sighting is used.
Installation of wall panels in frame buildings is carried out in a certain sequence. Internal wall panels are installed during the installation of the building before the installation of the ceiling of the overlying floor. The stiffening walls are fixed immediately after installation in accordance with the project. External wall panels, which ensure the stability of the frame structures, are also installed during installation with a lag of no more than one floor. Wall panels that do not affect the stability of the frame are most often mounted vertically in one-story buildings and horizontally in multi-story buildings. In heavy-frame industrial buildings, exterior wall panels are usually installed in vertical strips. In multi-storey civil buildings, external wall panels are fed during installation by the same crane as the frame elements. In industrial one-story and multi-story buildings with a heavy frame, the outer walls are mounted in a separate stream using self-propelled cranes. Wall panels of all types are slinged, as a rule, with a two-branch sling. When installing multi-storey frame buildings, the length of the branches of the sling should be such that the hook and the lower block of the crane hoist when the panel is installed are higher than the ceiling of the next floor. The supply of wall panels to the place of installation in frame buildings is complicated by the previously installed frame structures, therefore, when lifting, the wall panels are kept from turning and hitting the structure with two hemp rope guys. The panel is installed on the bed vertically or with a slight inclination outside the building to ensure that the panel is firmly supported on the bed solution. The outer tape panels are attached with two corner clamps to the columns; wall and panel of a blind area - with struts to the floor slabs. With the same devices, the panel is brought to a vertical in the plane of the wall. To check the verticality of the panels, a plumb line is most often used. Before removing the slings, the bottom of the panel is seized by welding. Finally, the panels are fixed by welding them to the frame elements.
If the panels are mounted before the installation of the girder or crossbar, when slinging, two hemp rope braces are tied to the panel of such length that when the panel is fed 1.5 m above the top of the columns, the end of the bracing is on the ceiling. The panel is lowered between the columns turned 90 degrees from the design position, temporarily fixed with a tray clamp or clamp to the column. The verticality of the panel is checked with a plumb line and by the risks on the column. If the crossbar is installed, the strapped partition cannot be brought under the crossbar, so the top of the panel is re-fastened during its installation. To do this, holding the panel by the braces, it is lowered next to the crossbar and stopped at a height of 10-15 cm from the ceiling. Squeezing the bottom of the panel, install it on the mortar bed. If necessary, correct the position of the bottom of the panel. The top of the panel is temporarily secured with a chain or staple. The chain is passed through the mounting loops of the panel and wrapped around the crossbar, the open ends are connected. Window panels are installed during the installation of wall panels or after their installation. Window panels are installed one above the other, resting them on supporting consoles made of large profile corners (150-200 mm) welded to columns or embedded parts. Window panels are often mounted in enlarged blocks. Sometimes they are enlarged together with half-timbered houses, imposts. To do this, the bindings are assembled and attached below to the fachwerk elements. Lantern top-hung bindings are mounted from the slabs of the coating manually or using blocks and winches, and fixed from the side or leaning ladders.
Installation of the walls of large-block buildings is carried out within the area after the installation of all structures of the underlying tier is completed. Blocks, as a rule, are slinged with a two-branch sling for two mounting loops. High wall blocks, if they are stored in a stack in a horizontal position, are previously transferred in the same position to the site, where they are transferred to a vertical position.
It is impossible to tilt the blocks directly in the stack, because if the lower edge of the block slips, then the jerk of the crane boom can lead to an accident. If, during the installation of the upper floors of the building, light blocks are slinged with a four-branch sling, feeding two blocks to the floor at the same time, then during the installation of the first block, the second block is temporarily placed on the ceiling above one of the internal load-bearing walls. If two textured blocks of outer walls are lifted, then the inner faces of the blocks should touch when lifting. A mortar bed is arranged on a cleaned base. Lighthouses are laid near the outer edge of the block at a distance of 8-10 cm from the side faces. The correctness of the installation of the top of the block is checked by mooring and sighting on previously installed blocks. The horizontality of the top of the block in the longitudinal direction is controlled by the rule with the level and sighting on previously installed blocks. The correct installation of the top of the lintel block is checked by measuring the distance from the mark of the top of the block to the reference quarter of the lintel with a meter or template, and the lighthouse blocks of the internal walls - to the top of the block. The top of the gable blocks is checked along the mooring stretched along the slope of the gable.
Minor deviations in the position of the block along the pediment are corrected by shifting it along the longitudinal axis of the wall. Jumper blocks cannot be moved along the walls, as this may cause the blocks of the lower tier to move. Installation of panels of external walls of large-panel buildings begins:
walls of the basement - after the installation of foundations; walls of the first floor - after completion of work on the underground part of the building; on the second and subsequent floors - after the final fixing of all structures of the underlying floor.
On the mounting horizon, two beacons are installed for each side panel at a distance of 15-20 cm from the side faces. For panels of external walls, beacons are located near the outer plane of the building. The panel supplied by the crane is stopped above the installation site at a height of 30 cm from the ceiling, after which the panel is directed to the installation site, while controlling the correct lowering of the panel into place. The correctness of the installation of the outer wall panels in place of the base is checked along the cut line of the walls of the underlying floor.
The installation of the bearing panels of the internal walls is carried out in the same way as the external ones, with the installation of two beacons. Non-bearing panels and partitions are installed directly on the solution. When installing gypsum concrete partitions in front of the bed, a strip of roofing felt, roofing felt or other waterproofing material 30 cm wide is placed on the base; the edges of the strip bent upwards during the construction of the floors protect the partition from moisture. Installation on the mortar and alignment of the panels of the transverse walls is greatly facilitated if the project provides for the insertion of the panel into the junction of the outer panels. The end ribs of the outer panels in this case serve as guides. For temporary fastening of the end of the panel adjacent to the outer wall, it is wedged; the free end of the panels and partitions is fixed with a triangular post; a screw device at the top of the post makes it easier to bring the panel into the plane of the wall. If the panel is only adjacent to the panels of the internal walls, the adjoining end is temporarily fixed with a spacer or angle clamp.
Installation of reinforced concrete shells covering public buildings
The installation of reinforced concrete shells for coverings of public buildings (transport, sports, entertainment, shopping facilities, etc.) is carried out according to two main technologies for mounting prefabricated monolithic shells:
at ground level - on the conductor, followed by lifting the fully assembled shell to the design level using erection cranes; at design levels.
The main method is the installation of prefabricated shells at design elevations, which is carried out on mounting support devices or with the support of enlarged shell elements on the supporting structures of the building - walls, contour trusses, etc.
A long cylindrical shell measuring 12x24 m is assembled from side elements in the form of gable prestressed beams and curved slabs measuring 3x12 m. The installation of the building frame begins with the installation of columns. Depending on the parameters of the erection crane, two options for organizing the installation are used: in the first case, the crane beams are installed immediately after the installation of the columns in a separate stream, and the installation of the shell is carried out by a crane located outside the span of the mounted shell; in the second, the assembly is carried out by a crane moving inside the erected span of the building. Under the side elements after their laying, temporary tubular supports are installed, since before the joints are monolithic, they are not able to perceive bending forces from the weight of separately lying shell elements. Enlargement of end plates with puffs is carried out on enlargement stands. After the installation of all elements, the reinforcement outlets are welded and the joints are monolithic. The spinning is carried out after the concrete has set 70% of the design strength at the joints.
Installation of free-standing shells
Installation of free-standing shells (under free-standing shells means shells of 36x36 and 24x24 m in size from slabs of 3x3 m in size, the shell of which rests on four diaphragm trusses that are not structurally connected with adjacent shells) is carried out using conventional erection cranes. Such shells are assembled on special devices - inventory mobile conductors. The conductor moves along the railway tracks, installed on a solid foundation - concrete preparation, prefabricated slabs, ballast layer. When erecting a building with multiple shells, the complete assembly of the conductor is performed once, and then the conductor is moved to the next cell. Installation of the shell begins with the installation of a diaphragm truss located at the end of the span, then a second truss is installed along the outer wall. The trusses are fastened together with a spacer and fixed with braces. After that, the conductor is assembled by installing support carts, racks, two supporting trusses and lattice runs. After alignment and temporary unfastening of the conductor with rigid connections between the bogies (braces - behind the columns and struts - to the trusses), part of the runs are removed and a third contour truss is mounted, which, after alignment with struts, is attached to the conductor. After that, the crane is moved into the bay and the installation of the corner plates of the shell and then the remaining plates in the established sequence is started. The slabs are laid on the support tables of pre-calibrated trellised conductor runs. After mounting half of the shell plates, the crane leaves the cell, installs the previously removed runs in place and then puts the fourth contour truss. The remaining plates are mounted in a similar mirror sequence.
In the construction of multi-span industrial buildings covered with shells of double curvature measuring 36x38 or 24 * 24 m, inventory conductors are used that move from position to position along rails. In a span or simultaneously in several spans, conductors are installed and then raised to the design marks, which are circular mesh structures that repeat the outlines of the shell. Contour trusses of the shell are installed on the columns with the help of erection cranes. After laying the prefabricated slabs, which is produced from the contours of the shell to the center, and reconciling their position, the butt joints are welded and the seams are monolithic. After the concrete at the joints reaches 70% of the design strength, the shell is unrolled, the conductor is lowered into the transport position and moved along the rails to the adjacent position.
The installation of multi-wave shells 18x24 m in size from 3x6 m slabs has the peculiarity that adjacent shells are based on a common contour truss 24 m long, and adjacent shells are monolithic along the upper belt of 18-meter contour trusses. During the construction of a two- or three-span building, installation is carried out on two or three conductors. The order of assembly and installation of conductors is the same as for free-standing shells, but the assembly order is different: first, the first conductor is installed, then two 18-meter diaphragm trusses are installed and attached to it - one extreme and one middle (in a single-span building - both extreme) and a 24-meter extreme truss. On 18-meter trusses, before lifting, they install running scaffolds and elements of steel inventory formwork. After installation, alignment and unfastening of the trusses, the corner zones are welded and the shell elements begin to be mounted. When erecting a multi-span building, after fixing the trusses of the first shell, trusses of adjacent shells are installed. In order to avoid tipping, they are unfastened between themselves by rigid struts welded in the corner zones to the embedded parts of the upper chords. Thus, it is possible to install conductors in the remaining spans. The installation of the shell begins with the laying of corner plates, then the contour plates of the far row and the middle are installed. Ordinary slabs are laid on the conductor beams. After installing the middle row slabs, a 24-meter truss is placed, and then the last row of slabs is laid, which are mounted through the installed truss. After that, the releases of reinforcement and embedded parts are welded. Prior to embedding the joints, the installation of the first row of slabs in the adjacent shell must be completed. Monolithic joints start from the corner zones and the junction of slabs to 18-meter trusses, and the remaining joints are monolithic in the direction from 24-meter trusses to the top of the vault.
Shells of double positive curvature 18x24, 24x24, 12x36 and 18x36 m in size are mounted in enlarged blocks assembled on stands from 3x6 or 3x12 m panels. The length of the enlarged block corresponds to the span of the shell. After that, the block is installed with a crane in the design position on pre-mounted side elements.
Byte hanging covers are a type of reinforced concrete shells. They consist of a reinforced concrete contour with a mesh of steel ropes (cables) stretched over it and prefabricated reinforced concrete slabs laid along them. The byte network consists of longitudinal and transverse steel ropes located along the main directions of the shell surface at right angles to each other. The ends of the guys are anchored with the help of special sleeves in the supporting reinforced concrete contour of the shell. During the installation of hanging roofs, a cable-stayed network of steel ropes is stretched onto the reinforced concrete contour, which ensures the design curvature of the shell. Then, prefabricated reinforced concrete slabs of the roof are laid along the ropes and their temporary surcharge in the form of a uniform filling of the shell with a piece load, the weight of which is taken equal to the weight of the roof and temporary load. After that, the seams between the prefabricated slabs of the shell are monolithic. After the concrete reaches the design strength, the temporary surcharge is removed. Thus, prestressing is created in reinforced concrete slabs, and they are included in the overall work of the coating, which reduces the deformability of the hanging structure.
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 with the 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 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;
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 as strong, are 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 a sufficiently high strength and in this indicator 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 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 of ventilation elements and blocks;
Installation of internal elements of the building.
Each of these types of work requires compliance with a special technology and the use of those steel and reinforced concrete structures that correspond to the tasks.
Initial construction stage
Before installation, 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 of all should lie on top, the bottom row or especially heavy structures are stacked on wooden substrates, free access of equipment to each structure and the possibility of grabbing the part by the crane boom, as well as convenience should be provided. rafters.
Foundation installation
The laying and installation of reinforced concrete structures in the pit is carried out according to a pre-compiled scheme, in which the location and assembly order of all components are accurately noted. Beacon blocks are initially laid in the pit. This is the name of reinforced concrete structures, which are located at the corners of the foundation and at the intersections of the axes of the structure.
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.
Precast concrete foundations are 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 placement in the correct position is carried out on weight.
Installation of columns
Before installation on columns, risks are applied on four faces above and below, indicating the axes. Reinforced concrete columns are laid out in front of the installation site in such a way that the crane makes a minimum of movements, and it is convenient for workers to inspect and fix the structures. The column is installed in a glass, reinforced on the foundation.
The column is attached to the crane hook in such a way that when it is lifted, it stands upright;
The crane puts the column in a vertical position. Depending on the weight of the column, different methods of lifting are used - turning, turning with sliding. For slinging columns, friction or pin grips are used;
Lowering to the foundation and reconciliation of the position. It is impossible to remove the column from the crane until its correct position is unambiguously determined using a level and theodolite.
The column should stand strictly vertically without the slightest inclination. Temporary fastening of the column for its adjustment is carried out using wedge liners.
The next step is to fix the column in the foundation glass. It is produced by forcing a concrete solution into the joints of the column (usually with a pneumatic 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
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 metal pipe spacers, which are attached before lifting begins.
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 the 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 preliminary preparation. 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.
The first slab is placed in a place previously marked on the farm, the rest - right next to it. If the building is framed, the floor slabs are laid after the installation of crossbars, purlins and spacer plates, and if it is frameless, after the walls have been built. When laying the slab on the surface, a "bed" is arranged from the solution. Excess solution is squeezed out by the plate itself. The first plate must be welded to the truss at four nodes, the next - at three. Inter-butt joints are sealed with a solution of cement and sand.
Installation of wall panels
Wall panels are installed after the construction of the building frame and the laying of floors. Before lifting, the panels are grouped into cassettes. With this method of storage, the installation of metal and reinforced concrete structures intended for the construction of walls is the most rational. Cassettes can be located between the wall and the faucet, behind the faucet, as well as in front of it.
Panels are installed by installers only from the inside of the building. Wall panels are placed along the entire height of the building with a section between two columns. Therefore, in one cassette there should be such a number of panels to cover the entire area along its entire height.
The panel is accepted by installers at the junction of this structure with the column. To do this, it is necessary to provide workers with access to these points in advance. If there is no transverse overlap, you will have to install cradles, scaffolds or a lift.
The installation of the first row of panels is of particular importance, therefore their position and compliance with the applied risks is checked especially carefully. External panels perform not only supporting and protective, but also aesthetic functions. Therefore, the seams between the panels must be sealed not only carefully, but very carefully and not exceed the established norms.
Internal wall panels are placed before the installation of the ceilings of the upper floor. The panels are attached to the columns with clamps, to the floor slabs - with struts. The final fastening 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, transportation, laying, 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.