Load-bearing structures of coatings of one-story industrial buildings. Reinforced concrete beams and trusses. Bearing structures of coatings
1.1 .. Industrial buildings are diverse space-planning and design solutions and are classified by the following main features: by appointment:
Production (in which the production of any type of product is carried out);
Service (warehouses, transport boxes, etc.);
Auxiliary (boiler rooms, transformer, pumping rooms, etc.);
Administrative and public (plant management, utility rooms, laboratories, etc.).
by number of storeys:
One-story;
Multi-storey;
by the number of spans:
Single-span;
Multi-span.
in terms of equipment with lifting and transport equipment:
Crane;
Gearless.
A characteristic feature of industrial buildings is their dependence on technological requirements, to which, in addition to the previously illuminated general requirements functional feasibility, strength, artistic expression and economy, include the following: - To workspace, which should be sufficient to accommodate technological equipment, engineering systems, full-fledged jobs for people employed in production;
- to the air, which should provide favorable conditions for the flow technological process and the work of people in accordance with sanitary standards specified in the relevant SNiP;
to temperature and humidity conditions, the parameters of which (temperature, humidity, air velocity) are strictly regulated by the norms for different types production processes.
The requirement for mechanization and automation production processes that are designed to significantly increase productivity and comfort in working conditions.
1 .2. Most one-story industrial buildings are prefabricated reinforced concrete structures(fig. 1.12). The rigidity of such buildings is ensured transverse frames(joint work of columns with trusses or roof beams), hard disk cover, crane beams and vertical ties.
Spans of one-storey frame industrial buildings are taken equal to 6, 9, 12, 18 and 24 m; column spacing - 6, 12 and 18 m; the height of the spans (distance from the floor to the bottom of the supporting structures of the pavement) - from 3 to 6 m with a module of 600 mm and from 6 to 18 with a module of 1200 mm.
Figure 1.12. Single-storey industrial buildings:
a - single-span, craneless; b - multi-span, equal height, crane; c - multi-span multi-span, crane; 1 - monorail; 2 - overhead crane; 3 - overhead crane; 4 - anti-aircraft lantern; 5 - strapping beam.
Part industrial building includes: foundations, columns, crane beams, roof structures (beams, trusses), roof trusses, roof slabs, stiffening ties.
The stability and spatial rigidity of single-storey frameworks is ensured by the joint operation of the transverse frames of the framework, interconnected by crane beams, a hard disk of the coating and vertical metal stiffening ties (Figure 1.13).
Detailed consideration of the design and construction features one-story reinforced concrete frame industrial building is the topic of one of the practical lessons, therefore, in this issue we will restrict ourselves to general information.
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Figure 1.13. Fragment of a one-story industrial building, completed
in a reinforced concrete frame:
1 - foundation; 2 - foundation beams; 3 - columns; 4 - crane beams;
5 - roof trusses; 6 - cover plates; 7 - lantern; 8 - window; 9 - wall;
10 - steel vertical stiffening ties.
The basis steel single-storey frame(Figure 1.14) are columns- rolling I-beams with consoles for supporting the crane beams (Figure 1.15a); in buildings with significant loads use stepped (two-branch) columns (Figure 1.15b).
Steel crane girders lengths of 6 and 12 m have an I-section, reinforced with double-sided ribs.
Steel roof trusses along the outline of the upper belt, they are with parallel belts or triangular (Figure 1.16). The trusses are made of rolled steel profiles and connected at the nodes by electric welding or high-strength bolts.
The spatial rigidity of the steel frames is provided by a system of horizontal and vertical ties installed between the trusses and the columns.
Figure 1.14. Fragment of a one-story industrial building, completed
in a steel frame:
1 - columns; 2 - crane beams; 3 - vertical ties; 4 - roof trusses;
5 - connections in the ridge of the farm; 6 - stretch marks; 7 - runs; 8, 9 - cross vertical and
horizontal links.
Rice. 1.15. Columns of the steel frame: a) - constant section
for the extreme row; b) - two-branch for the middle row.
1 - foundation; 2 - shoe; 3 - trunk; 4 - crane console; 5 - head; 6 - bleed
columns; 7 - lattice.
Rice. 1.16. Roof trusses and steel trusses.
1 - column; 2 - roof trusses; 3 - roofing; 4 - triangular
rafter truss.
Light refers to one-story industrial buildings with load-bearing elements made of high-strength steel or effective profiles, in which walls and coverings are made of thin sheet metal.
The following types of buildings are most common.
Structurally coated with rolled profiles or tubes(Figure 1.17). The columns in such buildings are made of I-beams or pipes, the crane beams are welded I-beams, the cover is a spatial structure in the form of a slab formed by pyramids from corners and pipes. Coating purlins - from channels, roofing and walls - from a thin steel sheet with effective insulation.
Rice. 1.17. Lightweight building.
1 - column; 2 - crane girder; 3 - spatial structure; 4 - cover
from steel flooring; 5 - antiaircraft lights; 6 - cover runs; 7 - wall
steel ltsta panels; 8 - window; 9 - basement panel; 10 - wall rack
half-timbered house; 11 - crossbars of half-timbered houses.
With supporting frames made of I-beams with a perforated wall(Figure 1.18). The transverse frames, together with the covering girders and the wall half-timbered elements, form the supporting frame of the building. The walls and covering of the building are made of sheet structures.
Buildings from lungs metal structures used in mechanical engineering, lightweight, food and woodworking industries.
Figure 1.18. A building with a frame made of perforated I-beams.
1 - foundation; 2 - frame made of steel I-beams; 3 - runs; 4 - cover from
asbestos cement sheets; 5 - walls made of asbestos-cement sheets; 6 - window;
7 - basement panel.
1 .3 The basis of multi-storey industrial buildings, which, as a rule, are made of frame with self-supporting or hinged (panel) walls, are based on standard unified two-, three- and multi-span dimensional schemes with a grid of columns 6x6, 6x9, 6x12 m (Figure 1.19 ). The height of the floors ranges from 3.6 to 7.2 m (except for cases with a large-span upper floor equipped with an overhead crane (Fig.19e)
The frame scheme is frame-braced, where lateral stability is provided by the stiffness of the transverse frames, and the longitudinal one is provided by vertical steel braces.
Rice. 1.19. Dimensional diagrams of multi-storey industrial buildings:
a - two-span; b - multi-span; c - two-span with an overhead crane; d - three-span with an overhead crane on the top floor; d - the same, with an overhead crane; L - span 6, 9 or 12 m; Hв -. Height of the upper floor (3.6; 4.8; 6 m); Hsr - middle floor height (3.6; 4.8; 6 m); Hн - the height of the lower floor (3.6; 4.8; 7.2 m); the column spacing in all schemes is 6 m.
The load-bearing frame of a multi-storey industrial building, made in a reinforced concrete frame, includes foundations, foundation beams, columns, girders, floor slabs, vertical stiffeners(fig 1.20) .
Rice. 1.20. Multi-storey beam frame.
1 - foundation; 2 - columns; 3 - crossbars; 4 and 5 - floor slabs and coverings.
Foundations and foundation beams are identical to those used in single-story frame buildings ( I. 3.3).
Columns with consoles of rectangular section 400x400 and 400x600 mm manufactured
They are 1, 2 or 3 floors high.
Column joints are arranged 900 or 500 mm above the level of the finished floor, since it is in these places that the bending moment is of greatest importance.
Rigeli, have a rectangular or T-section with a height of 800 mm, rest on the column consoles and are connected to them by welding embedded parts (Figure 1.21).
In cases where T-ledgers (type 1) are used, floor slabs rest on its lower shelves and have a length of 5550 mm (tie - 5050 mm), while when using rectangular crossbars (type 2), the slabs are stacked on top of the crossbar and have a length of 5950 mm (Figure 1.22). The cross-sectional dimensions of the slabs are 1500x400 and 750x400 mm.
Figure 1.21. Nodes of reinforced concrete beam frame: a) - column joint and support
crossbars; b) - joining the girder with the extreme column.
1 - column; 2 - floor slab; 3 - seams covered with concrete; 4 - steel
new column heads; 5 - outlets of fittings; 6 - butt rods; 7 - ri-
gel; 8 - butt plate.
The installation of the overlap begins with the bracing (intercolumnar) slabs located along the axes of the columns in accordance with the diagram shown in Figure 1.22. Tie plates transfer horizontal longitudinal forces to vertical stiffening ties. In the overlap system type 1 its total construction height is 900mm (800 + 100 - allocated to the floor structure), in the overlap system type 2- 1300 mm (800 + 400 + 100)
The type 1 ceiling system is used in buildings where there is a need to suspend transport or technological equipment from the ceiling.
Figure 1.22. Layout scheme for floor slabs:
a - type 1 system; b - type 2 system.
In industrial buildings where smooth ceilings are required, it is used girderless frame... (Figure 1.23).
Part bezel-less the frame includes the following elements: - columns square section, one storey high with a four-sided console at the top;
- small cap pyramidal shape with a square hole in the center for the passage of the column;
- pillars with outlets of fittings;
- flight slabs square shape with reinforcement outlets around the perimeter.
Column joints have the same structure as in the beam frame. Ka
The pilots rest on the four-sided console of the column, followed by the monolithing of the joint with concrete. The pillar slabs are supported on the shelves of the capitals, welding the reinforcement outlets and embedding the joint with concrete. The spans are supported along the contour, and the outlets of the reinforcement are welded with embedded parts on the bottom plates (Figure 1.23b).
Figure 1.23. A bezel-less frame of a multi-storey industrial building .: a) - a fragment of a building;
b) - frame node.
1 - foundation; 2 - column; 3 - capital; 4 - column plates; 5 - span-
naya stove; 6 - four-sided console.
The coating of an industrial building determines the durability, character of the interior space and the appearance of the building. It accounts for 20 to 50% of total cost one-story building.
By heat engineering qualities coatings are divided into insulated and non-insulated (cold). They are chosen taking into account the requirements of the microclimate conditions of the premises, the climatic characteristics of the construction area and the method of removing snow from the roof of the building.
Insulated coatings are arranged over heated rooms. The thickness of the insulation is prescribed so as to exclude the formation of condensation on the inner surface of the coating. Endows are often made less insulated than the main coating, which contributes to their greater heating and excludes the accumulation of snow and the formation of ice.
Uninsulated coatings are arranged in unheated buildings and with excessive heat release.
By constructive schemes coatings are classified into planar and spatial. In the first, the supporting and enclosing structures operate mainly independently of each other. Secondly, the functions of the supporting and enclosing structures are combined. Spatial coverings, having curved surfaces of rational geometric shape, have high rigidity, reduce material consumption and are advisable in buildings with spans exceeding 30 m.
The coatings must have good waterproofing, heat protection, must be strong, durable and reliable in operation, have the necessary fire resistance and fire safety, be industrial, have simple and reliable nodal interfaces of structural elements.
Coating constructions
Coverings of industrial buildings, as a rule, are arranged without attic. They consist of supporting and enclosing structures.
The load-bearing truss structures are trusses, beams, arches and frames. They support the enclosing part, giving it the required slope, corresponding to the roofing material.
Fencing includes flooring (reinforced concrete slabs, asbestos-cement or metal sheets, etc.), vapor barrier, insulation, leveling screed and waterproofing.
In non-insulated ("cold") coatings, there is no vapor barrier and insulation.
In single-storey industrial buildings, the most common coverings are made of large-sized slabs, laid along the upper belts of truss structures. When using floorings made of small-sized elements, the latter are supported on girders laid on the rafter structures.
Bearing structures of coatings
The supporting structures of the coatings are made of reinforced concrete, metal, wood and combined (from the materials listed above, for example, metal-wood trusses, etc.).
Metallic coatings are durable and lightweight structures. They are easy to manufacture and install and are highly prefabricated structures. Reinforced concrete coverings are fire resistant and durable.
Reinforced concrete roof beams and trusses.
Reinforced concrete beams are used in single-slope, multi-slope and low-slope, as well as flat ( i=1:20) coverings of one-story industrial buildings with spans ( L) from 6 to 18 m.
The beams of single-slope, flat and low-slope pavements have a rectilinear upper belt (Fig. 1 a, b, c), and in gable beams the upper belt has a broken outline with a slope i= 1:12 (fig. 2).
The design of the beams allows the attachment of overhead cranes with a lifting capacity of up to 50 kN.
For spans of 6 and 9 m, the beams have a T-section with a support height of 590 and 890 mm.
Beams with spans of 12 and 18 m are made of I-beams or rectangular sections with a support height of 890, 1190 and 1490 mm. I-beams with a wall thickness of 80 mm are reinforced on the supports with massive vertical ribs. To reduce the mass in the beams of rectangular cross-section, holes are arranged (Fig. 2 b). Such beams
the supporting parts are easy to manufacture and facilitate the wiring of the upper communications, but they have a greater weight than T-or I-section beams.
On the upper belt of reinforced concrete beams, embedded elements (M) are provided for fastening the girders or slabs of the covering, on the lower belt and wall - for fastening the overhead tracks, and in - steel sheets with cutouts for fastening the beams to the columns. The support of the beam on the column is shown in Fig. 3.
b) d)
v 
)
Rice. 1. Reinforced concrete beams with a span of 6, 9 and 12 m:
a) for single-slope roofs ( L= 6, 9 m);
b) for flat coatings ( L= 12 m);
c) for low-slope coatings ( L= 12 m)
d) section of beams for b) and c)
a
2 - 2
Rice. 2. Gable reinforced concrete beams:
a) solid section for L= 6.9 m;
b) lattice for L= 12 and 18 m
Rice. 3. Supporting a reinforced concrete beam on a column
Reinforced concrete trusses They are used to cover spans of 18, 24 and rarely 30 m. According to the outline of the belts, they are segmental, arched without bevel and diagonal, with parallel belts and polygonal (Fig. 4).
Rice. 4. Outlines of truss belts: a - segmental; b - polygonal;
в - trapezoidal; d - with parallel belts; d - triangular
Triangular trusses are mainly used for roofs made of asbestos-cement and metal sheets, and with parallel belts - for flat roofs for roll roofing.
To give the roof small slopes, segmental and arched trusses with columns are used to support the covering panels on them. Such "horn" trusses for low-slope pavements are shown in Fig. 5 a.
The most rational in terms of material distribution are segmental and arched trusses with a broken or curved upper belt. Compared to trusses of other shapes, there is less effort in the lattice elements of these trusses, which allows the lattice to be made thinner. Parallel chord and polygonal trusses have a simple configuration and are good because they are interchangeable with steel trusses. However, their disadvantages include a relatively powerful lattice and a large height, which leads to an overconsumption of material on the walls and an increase in the building's of little use, in addition, they require additional vertical and horizontal ties in the coating.
The support of a reinforced concrete truss on a column is shown in Fig. 6.
Rice. 5. Reinforced concrete bezel trusses:
a - for a low-slope roof;
b - for pitched roof
Rice. 6. Supporting a reinforced concrete truss on a column
The spatial system, consisting of columns, crane beams and supporting structures of the coating, is called frame one-story industrial building.
The vertical bearing elements of the reinforced concrete frame are called columns. According to their location in the building, the columns are divided into extreme and middle ones.
Columns of constant cross-section (cantilever)(Fig. 7) is used in buildings without overhead cranes and in buildings with overhead cranes.
The columns of the outer rows have a rectangular section of constant height. The middle columns, having a cross-sectional size of less than 600 mm in the plane of the transverse frame, are equipped at the top with double-sided consoles with such a protrusion so that the length of the platform for supporting the covering structure is 600 mm. With a cross-sectional size of 600 mm or more, the columns do not have consoles.
In the columns adjacent to the end walls, embedded parts must be provided from the side of the walls for fastening the half-timbered posts, which have a zero reference to the longitudinal axes.
Rice. 7. Prefabricated reinforced concrete columns for craneless spans of one-story buildings:
a - extreme columns; b, c - middle columns;
1 - embedded steel parts for fastening trusses or roof beams;
2 - the same for welding anchors fastening the wall to the columns;
3 - risks; 4 - anchor bolt
Columns are made of B15-B30 class concrete. The main working reinforcement is a rod made of hot-rolled steel of a periodic profile of class A-III.
Columns of rectangular cross-section for a building with bridge cranes, having consoles(Fig. 8, a, b), used in buildings with a span of 18 and 24 m, up to 10.8 m high, equipped with overhead cranes with a lifting capacity of 10-20 tons. The columns have a rectangular cross-section both in the upper (above the crane) and in the lower (crane) part.
Rice. 8. Precast concrete columns for crane spans:
a, b- single-branch (extreme and middle); c, d - two-branch;
1 - embedded parts for fastening beams or roof trusses; 2 - the same
for welding anchors that fasten the wall to the columns; 3 - risks;
4 - anchor bolts; 5 - embedded parts for fastening crane beams
Columns of the inner and outer rows, installed at the locations of the vertical ties, must have embedded parts for fastening the ties.
Columns are made of concrete of class B15, B25. The main working reinforcement is a rod made of hot-rolled steel of a periodic profile of the class A-III.
Two-leg columns(fig. 8, c, d) are used in buildings with a span of 18, 24, 30 m, a height of 10.8 to 18 m, equipped with overhead cranes with a lifting capacity of up to 50 tons.
For the extreme columns with a step of 6 m, a height of not more than 14.4 m and a crane lifting capacity less than or equal to 30 t, a zero reference is adopted, and in other cases - 250 mm.
The columns are designed in the lower part with two legs and connecting braces. The branches, struts and the top of all columns have a solid rectangular cross-section.
Columns are made of concrete of class B15, B25. The main working reinforcement is a rod made of hot-rolled steel of a periodic profile of class A-Sh.
The lower parts of reinforced concrete columns inserted into the glass are not included in the nominal column height. The columns are intended for use where the top of the foundations has an elevation of -0.150. The length of the columns is selected depending on the height of the workshop and the depth of embedding into the glass of the foundation.
In buildings with truss structures, the length of the middle columns is reduced by 700 mm.
Crane and strapping beams
Reinforced concrete crane beams(Fig. 9) are used in buildings with a column pitch of 6 and 12 m, with a crane lifting capacity of up to 30 tons. The beams have T and I-sections with thickening of the walls on the supports. Unified dimensions of beams are taken depending on the pitch of the columns and the lifting capacity of the cranes: with a column pitch of 6 m, the beams have a length of 5950 mm, a section height of 800, 1000, 1200 mm; with a column pitch of 12 m, the length of the beams is 11 950 mm, the height is 1400, 1600, 2000 mm. They are made of concrete of class B25, B30, B40 with prestressed reinforcement.
By location in the building, run-of-the-mill crane beams and end beams are distinguished. They differ in the location of the insert plates.
In the beams, embedded elements are provided for fastening to the columns (steel sheets) and for attaching crane rails to them (tubes with a diameter of 20-25 mm through 750 mm in the length of the shelf).
The crane beams are fixed to the columns by welding of embedded elements and anchor bolts. Bolted joints are welded after final alignment. The rails are fastened to the crane girders with steel paired legs spaced 750 mm apart. Elastic spacers made of rubberized fabric with a thickness of 8-10 mm are placed under the rails and legs.
In order to avoid impacts of overhead cranes on the end walls of the building, steel stops equipped with a wooden bar are arranged at the ends of the crane runways.
Strapping reinforced concrete beams(Fig. 10) are designed to support brick and small-block walls in places where the spans heights differ, as well as to increase the strength and stability of high self-supporting walls. Usually, beams are arranged over window openings. Reinforced concrete strapping beams have a length of 5950 mm, a section height of 585 mm, a width of 200, 250, 380 mm. They are installed on steel support tables and fastened to the columns using steel strips welded to the embedded elements.
Rice. 9. Prefabricated reinforced concrete crane girders:
a - a span of 6 m; b - a span of 12 m; v - support of the crane girder
per column ( general form); d - the same, from the facade and in section;
1 - embedded parts of the column; 2 - the same crane girder; 3 - steel bar; 4 - steel plate; 5 - embedding with concrete; 6 - holes for fastening the rail
The walls above the strapping beams can be solid, with separate openings, with strip glazing.
The beams are made of B15 class concrete.
Rice. 10. Strapping beams, their support on columns:
a - rectangular beam; b - rectangular beam
sections with a shelf; c - support of the beams (bottom view) on the steel console;
1 - embedded parts; 2 - welded metal console; 3 - mounting plate
Roof and roof beams and trusses
In building coverings, load-bearing elements are beams and trusses, laid across or along the building.
By the nature of the laying, beams and trusses are: rafters, if they overlap the span, support the roof structures supported on them, and rafters, if they overlap the 12-18-meter steps of the columns of the longitudinal row and serve as a support for the rafter structures.
Reinforced concrete roof beams(fig. 11) cover spans 6, 9, 12 and 18 m.
Rice. eleven. Reinforced concrete roof beams:
a - single-slope T-section; b - single-slope I-section;
in-gable (span 6-9 m); g-gable (span 12-18 m);
d- lattice (span 12-18 m); e - with parallel belts;
1 - supporting steel sheet; 2 - embedded parts
For their manufacture, concrete of class B15-B40 is used. On the upper belt of the beams, embedded parts are provided for fastening the cover plates or purlins, on the bottom flange and the beam wall - embedded parts for fastening the tracks of the overhead crane.
The beams are attached to the columns by welding of embedded parts.
The names of the beams depend on the outline of the upper chord.
Single slope beams are used in single-span buildings. The beams have a T-section with a thickening on the supports and a wall thickness of 100 mm. For spans of 12 m, prestressed I-beams are used.
Gable beams are intended for buildings with pitched roofs. For spans of 6 and 9 m, T-section beams with a thickening on the support and a wall thickness of 100 mm are used. For 12-18 meter spans, I-beams with a vertical wall 80 mm thick and with prestressed reinforcement are intended.
Lattice beams have a rectangular cross-section with holes for pipes, electric cables, etc.
Beams Parallel belts used for buildings with a flat roof. They have an I-section with a thickening in the support nodes and a vertical wall thickness of 80 mm.
Reinforced concrete roof trusses(Fig. 12) are used in buildings with a span of 18, 24, 30, 36 m. Between the lower and upper chords of the trusses, there is a system of racks and braces. The lattice of the trusses is provided in such a way that the floor slabs with a width of 1.5 and 3 m rest on the trusses at the nodes of the struts and braces. Basically, slabs of 3 m are used, in especially loaded areas - 1.5 m.
Widely used segmented bevelless trusses with a span of 18 and 24 m, sections of the upper and lower chords are rectangular.
To reduce the slope of the coating for multi-span buildings, it is envisaged to install special racks (columns) on the upper belt of the trusses, on which the covering slabs are supported. Giving the pavement a slight slope provides best opportunity mechanization of roofing works, which creates greater reliability of the roof in operation. However, due to the need to increase the height of the outer walls at the same time, low-slope roofs are advisable in multi-span buildings.
Rafter farms are made of three types:
For low-slope roofs of greater heights;
For pitched roofs of lower height with the device of racks on the supports that serve as a support for the extreme decks of the covering;
With a sagging bottom belt.
In the supporting parts of the truss girder and in its middle lower node, platforms are provided for supporting the truss trusses. The trusses are made of concrete of class B25-B40. The lower belt is pre-stressed and reinforced with bundles of high-strength wire. For the reinforcement of the upper belt, braces and struts, welded frames made of hot-rolled steel of periodic profile are used.
The trusses are fastened to the columns with bolts and welding of embedded parts. The trusses are provided with embedded parts.
Rice. 12. Reinforced concrete trusses:
a, b - rafter segment diagonal;
v _ arched rafter bezel;
g_ bezel rafter with supports for the device of flat coverings;
d _ rafter with parallel belts;
e - rafter for pitched coverings;
g - rafter for flat surfaces
Snapping Columns to Building Alignment
In one-story industrial buildings with reinforced concrete and mixed frames, the columns of the outer rows have a zero reference with respect to the longitudinal alignment axes, i.e. the outer face of the column is aligned with the longitudinal alignment axis and coincides with the inner face of the wall railing. In this case, a gap of 30 mm should be provided between the inner edge of the panel and the column (Fig. 13).
Rice. 13. Binding of single-storey load-bearing structures
industrial buildings to center axes:
a- longitudinal outer walls and columns (craneless buildings);
b - longitudinal walls and columns (with cranes with a lifting capacity of up to 30 t);
v- longitudinal outer walls and columns (with cranes
lifting capacity up to 50 t); d - in the end walls;
d - in locations expansion joints(LH); e - a fragment of the building plan;
1 - walls; 2 - columns; 3 - overhead crane; 4 - bridge crane;
5 - half-timbered column; 6 - crane girder
Columns of the middle rows in reinforced concrete, steel and mixed frames have a central reference to the longitudinal alignment axis, i.e. the center axis of the middle row of columns is aligned with the cross-sectional axis of the above-crane part of the columns.
The columns of the outer rows in the steel frame in relation to the longitudinal center line have a reference of 250 mm and are aligned with the inner edge of the wall panel with a gap of 30 mm.
The end columns of the main rows of any frame in relation to the extreme transverse alignment axis have a reference of 500 mm, i.e. the column axis is 500 mm behind this transverse center line.
All half-timbered columns are installed at the ends of the spans with a step of 6 m and are designed to be hung on them wall panels and the perception of wind loads. Regardless of the type of material in relation to the transverse alignment axis of the span, the half-timbered columns have a zero reference.
In reinforced concrete and mixed frames with a span of 72 m or more, and in a steel frame - 120 m or more in the middle of the spans in the transverse direction, an expansion joint is provided, which is arranged by installing a pair of columns, the axes of which lag behind the axis of the expansion joint, combined with the next step axis, 500 mm each. This creates two temperature blocks that operate independently under load. To ensure the spatial rigidity and stability of the columns in the vertical direction, vertical steel ties are provided between the columns in the middle of the temperature block between the columns (with a column pitch of 6 m - cross, with a pitch of 12 m - gantry).
Longitudinal expansion joints or the transition of heights of longitudinal spans are solved on two rows of columns, while paired alignment axes with an insert of 500, 1000, 1500 mm are provided. In a building with a steel frame, the transition of heights is carried out on one column by changing the height of its branches.
The adjoining of two mutually perpendicular spans is carried out on two columns with an insert along the outer wall and at the level of the covering. The size of the insert is determined based on the thickness of the outer walls and on the column anchors.
In a building in the presence of electric bridge cranes, the vertical axes of the crane tracks lag behind the longitudinal alignment axes of the building by 750 mm (without a passage) and by 1000 mm (with a passage), and in the presence of overhead cranes, the vertical axes of the suspension and their movement lag behind the longitudinal alignment axes by 1500 mm.
Providing spatial rigidity reinforced concrete frame
The linkage system is designed to provide the necessary spatial rigidity of the frame. It includes:
· Vertical communications;
· Horizontal ties along the upper (compressed) belt of trusses;
· Communication on lanterns.
Vertical links have:
· Between the columns in the middle of the temperature block in each row of columns: with a column pitch of 6m - cross; 12m - gantry. In buildings with craneless and overhead cranes, connections are installed only at a column height of 9.6 m. Connections are made from corners or channels and fastened to the columns using kerchiefs (Fig. 14);
· Between the supports of trusses and beams, ties are placed in the outermost cells of the temperature block in buildings with a flat covering. Without truss structures - in each row of columns, with truss structures - only in the outer rows of columns.
Horizontal ties are: slabs covering;
· At the ends of the lampposts, the stability of the rafter beams and trusses is ensured by horizontal cross braces installed at the level of the upper chord, in subsequent spans (under the lanterns) - by steel struts; with large spans and the height of the building at the level of the lower belt of the trusses, horizontal connections are arranged between the extreme pairs of trusses located at the ends of the building; in buildings with a pitch of extreme and middle columns of 12 m, horizontal trusses are provided at the ends (two in each span per temperature block). These trusses are located at the level of the lower chord of the trusses.
Precast concrete assemblies frame
Places of mates of different types of elements of the prefabricated frame are called nodes (Fig. 15). Nodes of reinforced concrete frames must meet the requirements of strength, rigidity, durability; immutability of mating elements under the action of installation and operational loads; ease of installation and termination.
Conjugation of a column with a foundation. The embedment depth of rectangular columns is 0.85 m, two-branch columns - 1.2 m. The joint is covered with concrete of a class of at least B15. Grooves on the column edges promote better adhesion of concrete in the joint cavity.
Support of the crane girder on the column projections. A steel sheet with cutouts for anchor bolts is welded to the beam supports (before its installation). On the column supports, the beam is fixed to the anchor bolts and the embedded parts are welded. The upper flange of the crane girder is fixed with steel strips welded to the embedded parts.
Connecting roof trusses and beams to a column. Steel sheets are welded to the supports of the truss structures. After installation and alignment, the support sheets of the rafter structures are welded to the embedded parts on the column head.
Support of truss structures on the column head. Embedded parts of abutting elements are welded with a ceiling seam.
Fastening overhead cranes to roof structures. The supporting beams of the cranes are bolted to the steel clips on the truss structures. Crossbeams redistribute the load from the overhead cranes between the truss nodes.
Conjugation of rafter and rafter elements similar to the fastening of trusses and beams to the head of the columns.
Multi-storey precast concrete frame
Multi-storey industrial buildings are erected, as a rule, with frame ones.
Depending on the type of overlap constructive scheme buildings can be girder and non-girder.
V girder reinforced concrete frames (Fig. 16) bearing elements are foundations with foundation beams, columns, crossbars, floor panels and coverings, as well as metal ties.
Rice. 14 Ensuring the spatial rigidity of the frame:
a - placement of horizontal ties in the coating; b - reinforcement of end
walls with crown trusses; v- placement of vertical ties in buildings
with flat coverings (without rafters);
d - vertical ties in buildings with rafters;
d - vertical cross ties; e - vertical portal links;
1 - columns; 2 - roof trusses; 3 - cover plates; 4 - lantern;
5 - wind farm; 6 - horizontal cross brace (at the ends of the lamppost); 7 - steel spacers (at the level of the upper chord of the trusses); 8 - crane beams; 9 - metal tie trusses between the supports of the truss trusses; 10 - vertical cross ties (in the longitudinal row of columns); 11 - roof trusses; 12 - vertical portal links (in the longitudinal row of columns)
Rice. 15. Nodes of the reinforced concrete frame of one-story industrial buildings: a - conjugation of the column with the foundation; b - support of the crane girder
on the column; v - conjugation of beams and trusses with a column; d - support
truss structures at the head of the column; d - mounting of suspended
cranes to load-bearing roof beams; e - support of rafters
and truss beams on the column head;
g - conjugation of trusses, trusses;
1 - foundation; 2 - column; 3 - monolithic concrete; 4 - grooves;
5 - embedded part; 6 - fastening bar; 7 - bolts М20;
8 - support sheet 12 mm thick; 9 - rafter beams;
10-welded ceiling seam; 11 - rafter beam;
12 - steel clip; 13 - bearing beam of the overhead crane;
14 - roof truss
Rice. 16. Multi-storey building with beamed ceilings:
a - a cross-section of a building with slabs supported on the ledges of the beams;
b - plan; в - details of the frame; 1 - self-supporting wall; 2 - crossbar with shelves;
3 - ribbed plates; 4 - column console;
5 - reinforced concrete element for filling expansion joints
Rice. 17. Coupling of columns with each other and with girders:
a - the structure of the joint of the columns; b - general view of the interface between the column and the girder;
1 - abutting column heads; 2 - centering gasket;
3 - straightening plate; 4 - the reinforcement of the column is working;
5 - the same transverse; 6 - butt rods;
7 - caulking and embedding with concrete of class B25; 8 - crossbar;
9 - floor slab (tie); 10 - column inserts
crossbars and slabs; 11 - welding of reinforcement, released from the column and girders;
12 - plate for plate welding
The foundations are arranged in columnar glass type.
Columns with a section of 400 x 400, 400 x 600 mm cantilever type with a height of one floor (for buildings with a floor height of 6 m and for the upper floors of three- and five-storey buildings), in two floors (for the two lower, as well as for the upper floors of four-storey buildings ) and three floors (for buildings with a floor height of 3.6 m). The outer columns for supporting the girders have consoles on one side, while the middle columns have consoles on both sides. Columns are made of concrete of class B15-B40.
Crossbars are laid on the console of the columns in the transverse direction. They are made of concrete of class B25, B30. The crossbars of the first type (with shelves for supporting the slabs) cover spans of 6 and 9 m. The crossbars of the second type have a rectangular cross-section, they are used in ceilings when installing sagging equipment.
Floor and roof slabs are manufactured with longitudinal and transverse ribs from concrete of class B15-B35. In terms of width, they are divided into main and additional ones, laid at the outer longitudinal walls. The main slabs laid on the top of the girders have cutouts at the ends (for the passage of the columns). For floor loads of up to 125 kN / m 2, flat hollow slabs are used, and sanitary panels are laid along the middle rows of columns.
Connections between the columns installed floor by floor in the middle of the temperature block along the longitudinal rows of columns. They are made of steel corners in the form of portals or triangles of the same design as in one-story buildings.
Binding columns of the outer rows and outer walls to the longitudinal alignment axes is zero, or the alignment axis of the building runs along the center of the column. The binding of the columns of the end walls is assumed to be 500 mm, and in buildings with a column grid of 6x6 m - axial. The columns of the middle rows are located at the intersection of the longitudinal and transverse axes. Frame nodes(Fig. 17) - these are support connections of the same type or different types of prefabricated elements that provide the spatial rigidity of structural rods. The main nodes include:
coupling of crossbars with columns is achieved by welding the embedded parts of the girders and consoles of the columns, as well as welding the outlets of the upper reinforcement of the girders with the rods passed through the body of the column. The gaps between the columns and the ends of the girders are filled with concrete;
column jointsmulti-storey buildings for ease of installation, they are provided at a height of 0.6 m from the floor level. The ends of the columns are equipped with steel heads. The joint is carried out by welding butt rods to metal heads, followed by monolithing;
floor slab joints. The laid slabs are connected by welding of embedded parts with girders, with columns and with each other. The cavities of the joints between the ribs are embedded in concrete. Bezelless reinforced concrete frame with a grid of 6x6m columns in the form of a multi-tiered and multi-span frame with rigid nodes and floor loads from 5 to 30 kN / m2 (Fig. 18).
The main elements of the frame: columns, capitals, intercolumnar and spans - are made of concrete of class B25-B40.
Columns with a height of one floor are installed on a 6x6m grid. In the upper part of the column there is a broadening (head) for supporting the capitals, which looks like an overturned truncated pyramid with a through cavity for mating with the ends of the columns.
Rice. eighteen. Multi-storey building with non-girder ceilings:
a - cross section; b - plan; 1 - self-supporting wall;
2 - column capital; 3 - intercolumnar slabs; 4 - the same spans
Fig. 19... Prefabricated non-girder floor:
a - plan and sections; b - general view;
1 - column head; 2 - capital; 3 - intercolumnar plate;
4 - the same span; 5 - monolithic concrete; 6 - monolithic reinforced concrete;
7 - shelf for supporting the flight plate; 8 - column
The capital is put on the head and secured by welding steel embedded parts. Hollow-core intercolumnar slabs are laid on the capitals in two mutually perpendicular directions and welded at the ends to the embedded parts of the capitals. After installing the column of the next floor, the joint is poured with concrete. Then, steel reinforcement is laid in the zone between the ends of the intercolumnar plates, welding it to the embedded parts. After concreting, the slabs work as continuous structures.
The overlap sections, bounded by intercolumnar slabs, are filled with square-shaped span slabs, resting them along the contour on the quarters provided in the lateral faces of the intercolumnar slabs.
The main nodes of a non-girder frame include (Fig. 19): column joints, located 1 m above the floor, the same structure as in the beam frame; the junction of the capital with the column. The capital is supported on the four-sided console of the column, welding embedded parts from below, and reinforcing plates on top. The gap between the column and the capital is monolithized with concrete of class B25; floor slab joints. The intercolumnar slabs are supported by the outlets of the reinforcement on the embedded parts, embedding the joint with concrete. The spans are supported by the outlets of the reinforcement on the embedded parts of the intercolumnar panels. After welding, the wedge-shaped grooves of the joints are monolithic.
In the construction of single-storey and multi-storey industrial buildings, a frame system is usually adopted as the carrier. The frame allows you to organize in the best way a rational layout of an industrial building (to obtain large-span spaces free of supports) and is most acceptable for the perception of significant dynamic and static loads that an industrial building is subjected to during operation.
In a one-story building, the load-bearing frame consists of transverse frames connected by longitudinal elements. Longitudinal elements perceive horizontal loads (from the wind, from the braking of cranes) and ensure the stability of the frame (frame) in the longitudinal direction.
The load-bearing transverse frame of the frame is composed of vertical elements - racks, rigidly fixed in the foundation and a horizontal element - a crossbar (beams, trusses), supported on racks. The longitudinal elements of the frame include: crane, strapping and foundation beams, load-bearing structures of the covering (including rafters) and special ties (Fig. 25.1).
Multi-storey buildings are constructed mainly using a prefabricated reinforced concrete frame, the main elements of which are columns, crossbars, floor slabs and ties (Fig. 25.2). Prefabricated interfloor ceilings are made with girder or non-girder. Prefabricated beam ceilings found application for 2-5 storey buildings with floor loading from 10 to 30 kPa.
Overlappings provide the spatial work of the frame as horizontal stiffening diaphragms. They perceive the horizontal force from the wind and distribute it between the frame elements. Vertical braces are reinforced concrete longitudinal and transverse internal walls, staircase-elevator cages and communication shafts, as well as steel cruciform elements installed between the columns.
The outer walls of one- and multi-storey buildings are curtain or self-supporting.
When considering the ratio of the relative cost (in% of the total cost of construction and installation work) of the main elements of industrial buildings, the load-bearing frame structures are 28% for single-storey buildings and 17% for multi-storey buildings, respectively, walls and coatings - 28% and 24% (overlappings 30%) , roof - 11% and 4%.
The structural scheme of the coating can be performed in two versions: with the use of purlins (additional elements) and without purlins. In the first version, along the building, along the beams (trusses), girders (mainly of a T-section with a length of 6 m) are laid, on which slabs of a relatively short length are supported.
In the second, more economical, run-free option, large-sized slabs are used with a length equal to the pitch of the beams (trusses). In construction, two types of slab structures are used with a length equal to the span: U-shaped slabs with flat slopes, 2T type slabs and vaulted slabs, such as KZhS (Fig. 25.3, 25.4). The use of such elements eliminates the need for beams in the coating.
The frames of one-story industrial buildings are made mainly of reinforced concrete (predominantly prefabricated), less often of steel. In some cases, use monolithic reinforced concrete, aluminum, wood. Each of these materials has its own advantages and disadvantages, therefore, the choice of material is carried out on the basis of a comprehensive assessment of its compliance with the complex of requirements for the building being erected, taking into account its subsequent operation.
Reinforced concrete structures have durability, fire resistance and low deformability; their use saves steel and does not require large operating costs.
The disadvantages include: large mass, laboriousness of making butt joints. The implementation of monolithic reinforced concrete structures in winter conditions is difficult and requires additional costs.
Weight loss and increase bearing capacity reinforced concrete structures are facilitated by the use of high-strength concrete and pre-stressed high-strength reinforcement. This made it possible to obtain effective thin-walled structures, to significantly expand the area of application of reinforced concrete (Fig. 25.5, 25.6, 25.7).
Lightweight bearing and enclosing structures are increasingly used in the construction of industrial buildings. Light structures are called structures, the total mass of which, per 1 m 2 of the building envelope, is no more than 100-150 kg. These include structures made of steel and aluminum alloys, glued timber.
The use of lightweight structures leads to a significant (by 10 - 15%) weight reduction production facilities and their cost, the efficiency of construction increases; the search for new constructive solutions of load-bearing and enclosing elements, the development and implementation of new effective heat-insulating materials is stimulated. The progressive method of construction of buildings (sections) is being expanded from the supplied standardized building structures prefabricated - steel spatial, lattice (cross), frame, etc. Along with this, the number of buildings made of mixed structures (columns - from reinforced concrete, trusses, beams - metal, from glued wood, etc.) is increasing.
Steel structures(fig. 25.8) in terms of their properties are more preferable to reinforced concrete. They have a lower mass and greater bearing capacity, high industrial manufacturing and relatively low labor intensity of installation, and their reinforcement requires less costs. The disadvantages are: susceptibility to corrosion and loss of load-bearing capacity in a fire under the influence of high temperatures, brittleness at low temperatures.
Comparative characteristics of reinforced concrete and steel frames are given in table. 25.1.
Aluminum alloy structures are lightweight and highly load-bearing, as well as corrosion-resistant. Aluminum is as ductile as steel, less brittle at low temperatures, and no sparks are generated under shock. The disadvantages of aluminum structures include a high coefficient of thermal expansion, low fire resistance (already at +300 ° C, it completely loses its strength), the relative laboriousness of joining elements, high cost... It is economically profitable to use aluminum alloys as enclosing structures, and as load-bearing structures - in large-span structures (to significantly reduce their own weight).
In contrast, timber structures have a low coefficient of thermal expansion. They are much cheaper than reinforced concrete and steel ones. Their main advantage is their high resistance in chemically aggressive environments, which allows them to be used in industrial buildings of chemical enterprises. However, wooden structures are subject to fire, decay, significant deformation under the action of loads due to swelling and shrinkage. The most progressive are glued wooden structures, in which thin boards are glued together with synthetic adhesives and impregnated with mineral salts, which makes them sufficiently fire-resistant and non-moisturized. The most widely used for industrial buildings are wooden beams covering spans of 6-12 m and segmental trusses for spans of 12-24 m. Glued wooden arches and frames are also used, which can cover spans up to 48 m.
Plastic structures are lightweight, corrosion resistant, and industrial. They are used as part of enclosing structures.
The frames of one-story industrial buildings of mass construction are made mainly of reinforced concrete. Steel structures are used in special cases, namely:
A) columns: more than 18 m high; in buildings with bridge cranes with a lifting capacity of 50 tons or more, regardless of the height of the columns; in heavy duty cranes; with a two-tier arrangement of bridge cranes; with a column pitch of more than 12 m; can be used as half-timbered stands; as load-bearing and enclosing structures for complete delivery; for buildings erected in hard-to-reach areas in the absence of a base for the production of reinforced concrete structures.
B) rafter and sub-rafter structures: in heated buildings with spans of 30 m or more; in unheated buildings with a light roof and overhead cranes with a lifting capacity of up to 3.2 t with spans of 12 m and 18 m; in buildings with spans of 24 m or more.
The use of linear elements in the reinforced concrete frame of a one-story building. independent in their purpose (columns from trusses, covering slabs, etc.) creates certain advantages both in the manufacture of elements in precast factories, and during installation on a construction site. It also allows them to be unified and typed.
The columns of the frame are supported on separate foundations, mainly of the glass type. In some cases, - with weak, subsiding soils, - strip foundations are arranged under the rows of columns or in the form of a solid slab under the entire building.
According to the method of construction and construction, foundations are divided into prefabricated and monolithic. Prefabricated foundations are arranged from one block, consisting of a sub-column with a glass or from a block (sub-column) and a slab. The blocks are made with a height of 1.5; 1.8-4.2 m with gradation in 0.3 m, sub-columns have dimensions in plan 0.9x0.9 ... 1.2x2.7 m with gradation in 0.3 m. The dimensions of the glass are correlated with the dimensions of the cross-section and the depth of the embedment of the columns. At the same time, the dimensions of the glass in the plan at the top by 150 mm and at the bottom by 100 mm exceed the dimensions of the section of the columns, and its depth is 800, 900, 950 and 1250 mm. When installing the columns, the gap is filled with concrete, which provides a rigid connection between the foundation and the column.
The elements of the prefabricated foundation are laid on the mortar and fastened to each other by welding steel embedded parts.
In cases where the mass of prefabricated foundation elements exceeds the carrying capacity of transport and assembly facilities, it is constructed from several blocks and slabs. When installing expansion joints, one foundation block can support from two to four columns. Prefabricated single-block foundations weigh up to 12 tons. Heavy foundations weighing up to 22 tons are usually made monolithic directly at the construction site.
The base of the foundation block has a square or rectangular shape sizes from 1.5x1.5 m to 6.6x7.2 m with a gradation of 0.3 m. The area of the base of the foundation is determined by calculation and depends on the value of the transmitted load and the bearing capacity of the foundation soil.
Precast foundations require a high consumption of concrete and steel. In order to reduce these costs, prefabricated lightweight ribbed and hollow foundations are used. Pile foundations with a monolithic or prefabricated grillage are widely used, which is also used as a sub-column.
Self-supporting walls of an industrial building rest on foundation beams, which are installed between the sub-columns on special concrete columns with a section of 300 x 600 mm. The foundation beams have a height of 450 mm for a column pitch of 6 m and 600 mm for a pitch of 12 m. The cross-section of foundation beams can be T-shaped, rectangular and trapezoidal. The most widespread are T-section beams as they are more economical in terms of concrete and steel consumption. The width of the beam on top is assumed to be 260, 300, 400 and 520 mm, based on the thickness of the outer wall panels. To exclude possible deformation of the foundation beam under the action heaving soils the entire length of the beam is covered with slag from the sides and bottom. This measure also protects the floor from freezing along the outer walls.
For single-storey buildings, unified columns of solid rectangular cross-section with a height of 3.0 to 14.4 m are used without cantilever (for buildings without bridge cranes and with overhead cranes), with a height of 8.4 to 14.4 m with consoles (for buildings with bridge cranes ) as well as two-branch ones with a height of 15.6-18.0 m for buildings with support, overhead cranes and craneless ones.
Crane beams are installed in buildings (spans) with supporting cranes for attaching crane rails to them. They are rigidly attached (with bolts and welding of embedded parts) to the columns and provide the spatial rigidity of the building in the longitudinal direction. The crane beams are made of metal and reinforced concrete. The latter are of limited use - with a column pitch of 6 and 12 m and a lifting capacity of overhead cranes up to 30 tons.
The frame of a multi-storey building must have durability, strength, stability, and fire resistance. These requirements are met by reinforced concrete, from which the frames of most industrial multi-storey buildings are made. The steel frame is used under heavy loads, under dynamic influences from the operation of equipment, during construction in hard-to-reach areas; the frame requires protection from the effects of fire with a heat-resistant lining, brick lining.
For industrial buildings with a small load on the floors (up to 145 kN / m) and auxiliary buildings (household, administrative, laboratory, design bureaus, etc.), an interspecific tie frame is used. The frame has a grid of columns 6x6, (6 + 3 + 6) x6 and (9 + 3 + 9) x6 m; storey heights from 3.6 to 7.2 m. Single unified elements have been developed - columns, floor slabs, stairs, wall panels.
Columns of multi-storey buildings are divided by type into extreme and middle ones, two stories high. For buildings with irregular floors of different heights, an additional nomenclature of columns has been developed - for one floor, which can be applied starting from the third floor. In this case, the joints of the columns are placed 600 - 1000 mm above the overlap level, which makes them more convenient to perform. The section of the columns is 400x400 mm and 400x600 mm, floor slabs are flat with voids 220 mm high and ribbed 400 mm high, 1.0 wide; 1.5 and 3.0 m (main) and 750 mm (additional). Crossbars - rectangular and T-section with flanges on the bottom, respectively, with a height of 800 mm and 450 and 600 mm.
Reinforced concrete rafter beams accept: T-section for a span of 6 m, I-section for spans 9, 12, 18 and 24 m, as well as rafter beams with a span of 12 m. m.
The bezel-less frame consists of columns with a height of one floor with a cross-section of 400x400 and 500x500 mm with square capitals measuring 2.7x2.7 m; 1.95x2.7 m and a height of 600 mm, as well as spans of overhead slabs with dimensions of 3.1x3.54x0.18 m; 2.15x3.54x0.18 m and 3.08x3.08x0.15 m. The capitals rest on the four-sided consoles of the columns and are attached to them welded joints... Span plates are laid on the capitals or consoles of the columns and are also fastened by welding steel elements, followed by cementing the seams with concrete. A square grid of 6x6m columns and floor heights of 4.8m and 6.0m are used (Figure 25.9).
Lesson 53-54 (9-10)
1. The foundations take the loads from the above-ground part, transfer them to the foundation.
2. The work of foundations - in changing conditions from loads, increased requirements for their quality.
3. Requirements for materials for foundations :
a) mechanical strength
b) high frost resistance
c) durability
d) resistance to aggressive groundwater.
4. Classification of foundations of industrial buildings :
A) by constructive solution: tape, columnar, pile.
B) by construction technology: monolithic and prefabricated
C) by deepening - shallow and deep.
Columnar foundations for industrial frame buildings (p. 180)
1. Monolithic under a reinforced concrete column: sub-column + glass + plate with steps. (rice)
2. The bowl has a widening on top for ease of installation and centering of the column.
3. The depth of the glass is 50-150 mm more than the column inserted into the glass.
4. The bottom of the column is fixed with sand or concrete, the gaps between the glass and the column are filled with concrete or mortar.
5. Two-branch columns - in a common glass or two glasses for each branch (b).
6. In expansion and settlement joints, each column needs its own glass.
7. If the seam is sedimentary, arrange for each column - its own foundation.
8. Preparation for the foundation - concrete of class B5 with a thickness of 100 mm.
9. The foundation slabs and the sub-column are reinforced.
10. Concrete for the foundation - class B 12.5, B15.
11. Working fittings - steel of classes A-II and A-111.
12. The sub-column is supported on one, two or three rows of foundation blocks.
13. The bottom row of blocks - on a sand preparation at a distance of 600 mm from each other.
14. National teams foundation slabs placed on a leveling layer of sand.
Foundations for metal columns (182)
1. Columnar with sub-column continuous cross-sections
2. The top of the sub-column is positioned at the -0.600 or -0.200 mark.
3. A support base is arranged near the column - a shoe. A steel sheet is laid under the column to evenly transfer the load to the concrete area of the foundation.
4. The base is deepened below the level of c.h. and concrete).
7. The bases are fixed to the foundations with anchor bolts embedded in the foundations during their manufacture.
8. The bolts are threaded through the base plate and other base members.
9. The height of the sub-column is not less than 700 mm
10. The walls of frame buildings are supported on the foundation beams between the sub-columns.
11. Under the gate to enter the workshop, foundation beams are not laid.
12. Wall sections within this column spacing rest on a monolithic foundation.
RC foundation beams (183)
1. Have a trapezoidal or tee section.
2. Their dimensions depend on the pitch of the columns.
3. Beams at the expansion joint and end walls are shortened by 500 mm.
4. The top of the foundation beams is 30 mm below the floor level.
5. Install the beams on a 20 mm thick cement-sand mortar grout.
6. The gaps between the ends of the beams and the columns are filled with the same solution.
7. On the foundation beams - waterproofing of walls - 1-2 layers of roll material.
8. In order to avoid deformation of the beams from heaving of soils from below and from the sides of the beams, backfill from slag, sand or brick crushed stone.
9. Beams are made of concrete of class B15-B30.
Pile foundations under the columns of industrial buildings
1. Driven or rammed piles + grillage from above + reinforced concrete shoe with a glass for columns.
2. Pile foundations are suitable when weak pounds occur at the surface of the earth and in the presence of pound waters.
Lesson 55-57 (11-13)
Topic 3.5.3. Reinforced concrete structures of industrial buildings
1. Frame of a 1-storey industrial building - columns + crane beams + coverings.
2. Columns of the frame: extreme and middle.
3. Types of columns
A) constant section (cantilever): 185
* for buildings with overhead cranes
* extreme - rectangular of constant cross-section, middle - with a console
B) rectangular section with consoles- fig. 186, a, b
* for a building with a span of 18 and 24 m, a height of up to 10.8 m with overhead cranes gr. 10-20 t.
* the outer columns are single-cantilevered, the middle ones are double-cantilevered.
V) two-branch columns(186, c, d)
for buildings with a span of 18, 24, 30 m, a height of 10.8 -18 m, with bridge cranes gr. up to 50 t.
G) prefabricated reinforced concrete columns for craneless spans of one-story buildings.