RU38789U1 - COMBINED SPATIAL REINFORCED CONCRETE FOUNDATION PLATFORM FOR THE CONSTRUCTION OF MULTI-STOREY BUILDINGS IN SPECIAL GROUND CONDITIONS AND SEISMICITY - Google Patents

Abstract

Prefabricated spatial reinforced concrete foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity refers to the construction of a spatial foundation platform with multi-storey buildings in special soil conditions and seismicity. The objective of the invention is the creation of a prefabricated spatial reinforced concrete foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity, which has greater reliability, strength, reduced metal consumption, ease of installation and operation. Prefabricated spatial reinforced concrete foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity, including the combined upper and lower plates, the lower plate is installed without burial on the outer surface of the soil with a sliding layer of materials with a low coefficient of friction on the base, between upper and lower plates formed a ventilated underground ventilated in all directions, in which the plates of the upper and lower zones are connected They are interconnected by reinforced concrete trusses with diagonal or dividing trusses or beams that have key protrusions entering the recesses of the upper and lower plates, the seams between the plates or trusses and keyed joints are all monolithic, and the embedded parts and the outlets of the reinforcement are welded, installed between the trusses or beams in the transverse direction cross connections, the location of trusses or beams is consistent with the topology of the load from the upper structure and can be oriented parallel to long

Description

The invention relates to the construction of a spatial foundation platform with multi-storey buildings in special soil conditions and seismicity.

Monolithic continuous solid reinforced concrete slabs are known, which are arranged on a special hardened base, are used for buildings and structures of residential, civil or industrial purposes with mandatory preliminary engineering preparation (hardening) of the soil base to obtain the specified characteristics of its rigidity (see article by Authors V.E.Seskov , V.N. Lyakh, TI Beach “Design and technology for the construction of thin foundation slabs”, “Construction” magazine, Belarus, BITU, Minsk, 2003 p. 252-257)

The design disadvantage is the low bending stiffness of the foundation slabs even at very significant thicknesses (i.e., at high consumption of reinforced concrete), in addition, the increased complexity of the construction

at a construction site, especially in winter conditions, as well as the need for preliminary compaction of the base to a considerable depth.

So, for example, this design has a flexural rigidity of the foundation slab many times (5-10) less than in the solution proposed by the authors due to its assembly with almost equal volume of reinforced concrete without the cost of compaction of the soil. This does not allow the efficient use of monolithic continuous slabs with uneven precipitation, in heaving and other weak soils, as well as on permafrost soils. The proposed prefabricated spatial reinforced concrete foundation platform is characterized in that it consists of prefabricated ribbed slabs with reinforced concrete trusses located between them, interconnected by means of key connections with the release of reinforcement, with the monolithic joints, joints between plates, slabs and trusses or beams, and embedded parts are welded. The location or orientation of trusses or beams is parallel to the long or short side of the building of a rectangular type. The pitch of the trusses is taken equal to or greater than the height of the spatial foundation platform. The proposed design solutions for prefabricated reinforced concrete foundation platforms (slabs) are not found in the literature.

The closest technical solution, taken as a prototype, is a spatial foundation platform (see patent No. 2206665, M. class. 7 E 02 In 27/32, 27/34, 27/35, spatial foundation platform, publ. BI No. 17, 2003), which includes interconnected

by means of metal elements, the upper and lower plates, the upper plate with the ribs down and the lower plate with the ribs up, are interconnected by a metal spatial truss with racks and braces with the formation of a single spatial structure for installation on the upper plate as on a common foundation platform, one or more reservoirs together with service tanks their pipelines and equipment. The dimensions of the bearing area of the spatial foundation platform are chosen larger than the dimensions of the bearing area of the foundation, the upper and lower plates together with the metal spatial sprengel form a blown underground ventilated in all directions, preventing heat exchange between the heated reservoir filler and permafrost soil.

Its disadvantages are significant metal consumption due to the use of metal connecting elements in the platform, which requires special anti-corrosion measures. In addition, the design was not specifically designed for multi-story buildings. The use of reinforced concrete for these purposes will increase the reliability of the structure and reduce the metal consumption.

The proposed design of a prefabricated spatial foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity allows you to orient the location of beams or trusses for different types of buildings.

The objective of the invention is to create a prefabricated spatial reinforced concrete foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity, which has greater reliability, strength, reduced metal consumption, ease of installation and operation.

The purpose of the invention is achieved in that the prefabricated spatial reinforced concrete foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity, including the combined upper and lower plates, the lower plate is installed without recesses on the outer surface of the soil with a sliding layer device made of materials with a low coefficient sliding friction along the base, between the upper and lower plates a ventilated underground ventilated in all directions is formed, in which the slabs of the upper and lower chords are interconnected by reinforced concrete trusses diagonal or dividing or beams that have key protrusions that enter the recesses of the upper and lower slabs, the seams between the slabs or trusses and keyed joints are all monolithic, and the embedded parts and outlets of the reinforcement are welded, between the trusses or cross ties are installed in beams in the transverse direction, the location of trusses or beams is consistent with the topology of the load from the upper structure and can be oriented parallel to minutes or a short side in the rectangular plan of the building, and in complex combination - combined, in a complex building structure possible combinations truss arrangement

or beams, with the round outline of the building, the trusses can be arranged radially, and the slabs can be segmented or trapezoidal, the pitch of the trusses is taken equal to or greater than the height of the platform, in the case of installing frame buildings, the slots have openings for glasses in which columns are installed, which are then monolithic with upper and lower plates in which the column is pinched.

The spatial platform is installed on a level base with a sliding layer of material with a low coefficient of friction, and its dimensions are taken much larger than the size of the building installed on it, this ensures a stable position of the building installed on the spatial foundation platform and creates the possibility of building on weak, heaving, permafrost soil and in seismic areas.

The connection of the upper and lower slabs with reinforced concrete trusses or beams diagonal or bezkrabosny create a new type of connection, and the seams between the trusses or beams and keyed joints are monolithic, embedded parts are welded. This ensures greater strength and reliability of the structure.

In the prototype, the use of only metal bonds in a spatial foundation platform requires certain anti-corrosion measures to increase durability. Replacing these bonds in whole or in part with reinforced concrete elements increases the durability of the proposed design.

The proposed design of a prefabricated spatial foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity allows you to orient the location of beams or trusses for different types of buildings.

Prefabricated spatial reinforced concrete foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity is presented in the figures:

Figure 1 is a General view of a prefabricated spatial reinforced concrete foundation platform, made using a dummy farm;

Figure 2 is a General view of a precast spatial reinforced concrete foundation platform made using a diagonal truss;

Figure 3 is a frameless reinforced concrete farm;

Figure 4 - diagonal reinforced concrete farm;

Figure 5 - key connection of farms with upper and lower plates,

6 is a location diagram of a precast spatial reinforced concrete platform under the building of a U-shaped type;

7 is a location diagram of a precast spatial reinforced concrete platform for a rectangular type building with a longitudinal arrangement of trusses or beams;

Fig. 8 is a layout diagram of a precast spatial reinforced concrete platform with a transverse arrangement of trusses or beams;

Fig.9 is a location diagram of a precast spatial reinforced concrete platform under a l-shaped building;

Figure 10 - arrangement of a precast spatial reinforced concrete platform for a round building in plan with a radial arrangement of trusses or beams.

Prefabricated spatial reinforced concrete foundation platform 1 (see figure 1) contains the upper 2 and lower 3 reinforced concrete slabs with shelves. Between the upper 2 and lower 3 slabs, the trusses 4 (see Figs. 1, 3) are mounted without beveling or diagonal (see Figs. 2, 4) with projections 5 (see Fig. 2). The ledges 5 of the trusses are included in the recesses 6 in the reinforced concrete upper 2 and lower 3 slabs and form keyed joints (see figure 5). Key connections of plates with beams are similar. In farm 4, reinforcement 7 is additionally produced. The seams between the upper 2 and lower 3 plates, trusses 4 and key joints are all monolithic, and the embedded parts are welded. Farms 4 are additionally reinforced with cross ties 8.

In the case of installing frame buildings in the slabs 2, holes 9 for cups are provided in which the columns are installed.

The bottom plate 3 is installed without recesses on the outer surface of the soil 10 with a sliding layer of materials with a low coefficient of sliding friction on the base.

Between the upper 2 and lower 3 slabs and trusses 4, a ventilated underground ventilated in all directions is formed, preventing heat exchange between the upper structure and permafrost soil.

The location of trusses 4 is consistent with the topology of the load from the upper structure and can be oriented parallel to long or short

side of a building rectangular in plan, and with a complex combination - combined. When installing buildings on a prefabricated spatial reinforced concrete foundation platform in a circular plan, the platform is made of trusses 4 diagonal or bezkarazny type in the plan installed radially. All seams are monolithic.

With a complex construction of the building, combinations of the location of the trusses are possible 4. The pitch of the trusses 4 is taken equal to or greater than the height of the platform, with a round outline of the building, the trusses 4 can be located radially. The dimensions of the area of support of the spatial platform are selected larger than the dimensions of the area of support of a multi-storey building. In the case of installing frame buildings, slabs have openings for glasses in which columns are installed, which are then monolithic with the upper and lower plates, in which the column is pinched.

Installation of a precast spatial reinforced concrete foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity is carried out as follows.

On the leveled base 10 with the installation of the sliding layer in the form of dry sand or materials with a low coefficient of friction, the lower plates 3 are mounted with installation in the recesses 6 between the lower plates 3 of the trusses of diagonal or bezborosny or plates protrusions 5 in the recesses 6, forming keyed joints. In farm 4, reinforcement 7 is additionally produced in plates 2 and 3. Seams between the upper 2 and lower 3 plates with keyed joints and trusses 4 are all monolithic, and embedded parts

and valve outlets are welded. This ensures a reliable connection. Farms 4 are additionally reinforced with cross ties 8.

With a complex construction of the building, combinations of the location of the trusses are possible 4. The pitch of the trusses 4 is taken equal to or greater than the height of the platform, with a round outline of the building, the trusses 4 can be located radially. In the case of installing frame buildings, slabs have openings for glasses in which columns are installed, which are then monolithic with the upper and lower plates, in which the column is pinched.

Feasibility study:

The authors made specific technical and economic comparisons on the consumption of reinforced concrete for the foundation of 5 and 9-story buildings and revealed significant savings in concrete compared to traditional and solid slab foundations (see the appendix).

1. The design of a prefabricated spatial reinforced concrete foundation platform on a leveled ground with a sliding layer device allows you to effectively build buildings on weak, subsidence, heaving soils, permafrost soils and in seismic zones with low laborious construction and installation, reducing metal consumption and increasing anti-corrosion properties.

2. The proposed design of a precast spatial reinforced concrete foundation platform has increased reliability of the construction of multi-story buildings in special unpaved under and

seismicity due to the design of the key connection of the upper and lower plates with trusses, the monolithic seams, the connection of trusses or beams and plates with the help of additional fittings, the choice of the sizes of the bearing area of the prefabricated spatial platform is larger than the bearing area of a multi-storey building.

3. Compared with the prototype reduced metal consumption.

4. The use of this design allows to reduce the metal consumption through the use of reinforced concrete beams or trusses, corrosion resistance is ensured.

5. The design allows you to build on the proposed platform of the building of various configurations and purposes.

4.3-Feasibility study for the use of spatial foundation platform

A technical and economic comparison was made on the consumption of reinforced concrete on the foundation of a 9-storey building for two cases: traditional options - strip and pile foundations; and unconventional solutions - a foundation with a thin slab [7]. Comparison with spatial foundations is not carried out, because There are no analogues. For comparison, you should determine the average load on the foundation surface of a 9-storey building in the city of Krasnoyarsk.

Note that the traditional comparison is carried out on the consumption of material or other indicators only on the foundations. In the case under consideration, the comparison of technical and economic indicators only on the foundations is inferior, especially when it comes to seismic areas. It is necessary to compare the entire buildings, since the adopted foundation in the form of a platform immediately increases antiseismicity, while the use of a buried foundation, including piles, requires additional antiseismic measures for the upper structure and creates conditions for the uncertainty of the survivability of these structures.

For technical and economic comparison, a methodology has been adopted, which is conducted on comparative examples taken from sources: [1, 2, 3, 4, 5, 7]. Given that the existing facilities vary in area and structure, to determine the order of the average value of the consumption of reinforced concrete on the foundation, all the data on the examples are approximately recalculated for the city of Krasnoyarsk and are given for two consumption indicators: for 1 m ^{2 of} the ground floor area and 1 ton of weight buildings. The foundation of all the above objects is calculated from the condition of soil characteristics according to the graduation project, in which bored piles with a bearing capacity of 71 tons and hanging piles with a bearing capacity of 53 tons are used on a 12-meter thick subsidence loam, which corresponds to the Northern district of the city of Krasnoyarsk. It is worth noting that the soil conditions given in the thesis project are far from the most unfavorable. So, in the same Severny microdistrict, the case is known when the piles do not reach the bearing layer 24 m. When calculating the volume of reinforced concrete for the foundation under such soil conditions, its value will increase significantly, thereby increasing the advantages of the foundation platform.

table 3
Comparative table of indicators of the consumption of reinforced concrete on the foundation for 9-story buildings No. Characteristics of a 9-storey building (Dimensions in plan (m)) Area (m ² ) Weight of the building, (t) The load of the building, (t / m ² ) The volume of reinforced concrete on the foundation (m ³ ) The rate of consumption of reinforced concrete foundation on 1 m ² building area for 1 t. building weight Pile Racks Hanging piles Pile Racks Hanging piles Pile Racks Hanging piles 1 2 3 4 5 6 7 8 9 10 eleven 1 9-storey residential building for small families in the city of Krasnoyarsk Panel building (17.4 × 42) 730.8 14555 19.9 427.9 508.5 0.59 0.7 0,029 0,035 2 Brick building (17 × 12) 204 2938 14 108.8 125.8 0.53 0.62 0,037 0,043 3 Central Research Institute of Housing, Series 90 Panel building. (23.4 × 12.3) 287.82 7053 24.15 184.8 242.65 0.64 0.84 0,026 0,034 4 Lenniiproekt, series 137 Panel building. Building area (27.6 × 10.8) 322.56 5961.7 18.15 186.1 219.6 0.58 0.68 0,031 0,037 5 TsNIIEP dwellings, series 85 Brick building. Building area (25.76 × 12.9) 316.8 7152.9 22.15 222.4 261.8 0.7 0.83 0,031 0,037 6 Average - - 19.67 - - 0.61 0.74 0,031 0,037 7 Building 630 m ² (21 × 30) on a spatial reinforced concrete platform (24 × 36) 864 12354.3 - 290 0.46 0.02 8 Reducing the consumption of reinforced concrete on a spatial platform - - - - - 1.3 1,6 1,6 1.85

CONCLUSION for traditional solutions: the use of a spatial reinforced concrete foundation platform allows reducing the volume of reinforced concrete in comparison with the foundation options from bored and suspended piles.

In addition to the advantages in the consumption of reinforced concrete, the spatial platform has a number of features:

- does not require excavation;

- can be collected at any time of the year;

- insensitive to precipitation;

- due to a decrease in sensitivity to horizontal seismic influences, it increases the reliability and survivability of the building;

- can be arranged on weak, loose, heaving, subsidence and other soils, the parameters of which may not be determined in advance;

- applicable for construction on permafrost soils;

- the top plate of the platform is used as a floor;

- as noted above, it is necessary to compare the entire buildings;

- for a spatial steel-reinforced concrete foundation platform, concrete consumption is several times less, but at the same time, the steel consumption for braces increases. For example, for an arched building of a closed type with a span of 24 m, including a steel-reinforced concrete spatial platform, the following indicators are derived:

1. The consumption rate of reinforced concrete per 1 m ^{2 of} the building area is 0.11 m ³ / m ² ;

2. The rate of consumption of reinforced concrete per 1 ton of building weight is 1.25 m ³ / t.

CONCLUSION for non-traditional solutions: monolithic continuous plates [7], which are installed on special sealed bases. The disadvantage of these designs is the low bending stiffness of the foundation plates, even with a very significant thickness, i.e. greater consumption of reinforced concrete, and in addition, increased laboriousness of construction at the construction site, especially in winter conditions, as well as the need for preliminary compaction of the base to a considerable depth.

So, for example, according to the Belarusian project, the bending stiffness of the foundation slab is many times (5 ÷ 10) less than in the proposed solution with almost equal volume of reinforced concrete (without the cost of compaction of the soil). This does not allow the effective use of these monolithic slabs in case of uneven precipitation, in heaving and other weak soils, as well as on permafrost soils.

In addition to foundations with a thin slab, a steel-reinforced concrete spatial platform is known (Patent No. 2206665) [8]. Its disadvantage is significant metal consumption and the need for special anti-corrosion measures. In addition, the design was not specifically designed for multi-story buildings (in the sense of the special load from them).

Possible design solutions for prefabricated reinforced concrete foundation platforms (slabs) are not found in the literature.

Literature:

1. diploma project Trukhina N.V. - "9-storey residential building for small families in the city of Krasnoyarsk", completed in 2001. The consultant of the section "Foundations and Foundations" - Kozakov Yu.N .;

2. Foundations and foundations: Reference book / G.I.Shvetsov, I.V. Noskov, A.D. Slobodyan, G.S. Goskova; Ed. G.I.Shvetsova. - M .: Higher. Shk., 1991 .-- 383 pp .: ill .;

3. Shereshevsky I.A. Construction of civil buildings. Textbook allowance for technical schools. - L .: Stroyizdat. Leningra. Otdel, 1981. - 176 p., ill .;

4. Shereshevsky I.A. Construction of civil buildings. Textbook allowance for technical schools. - L .: Stroyizdat. Leningra. Otdel, 1981. - 176 p., ill .;

5. Shereshevsky I.A. Construction of civil buildings. Textbook allowance for technical schools. - L .: Stroyizdat. Leningra. Otdel, 1981. - 176 p., ill .;

6. Chapter 4, section 4.2 of this work.

7. Seskov V.E., Lyakh V.N. Beach T.I. “Design and technology for the construction of thin foundation slabs”, “Budaunstva”, No. 1-3, 2003

8. Chapter 3, section 3.1 of this work.

Claims (1)

Prefabricated spatial reinforced concrete foundation platform for the construction of multi-storey buildings in special soil conditions and seismicity, including the combined upper and lower plates, the lower plate is installed without burial on the outer surface of the soil with a sliding layer of material with a low coefficient of friction on the base, between upper and lower plates formed ventilated in all directions, a blown underground, characterized in that the plates of the upper and lower the jars are interconnected by reinforced concrete trusses diagonal or dividing or beams that have key protrusions that enter into the recesses of the upper and lower plates, the seams between the plates or trusses and keyed joints are all monolithic, and the embedded parts and outlets of the reinforcement are welded, between trusses or beams in the transverse cross connections are established, the location of trusses or beams is consistent with the topology of the load from the upper structure and can be oriented parallel to the long or short side in the square a rectangular building, and with a complex combination - combined, with a complex construction of the building, combinations of trusses or beams arrangement are possible, with a round outline the trusses can be arranged radially, and the slabs can be segmented or trapezoidal, the truss step is taken equal to or greater than the height of the platform, in the case of installing frame buildings in the slots, holes are provided for glasses in which columns are installed, which are then monolithic with the upper and lower plates in which the column is pinched.