RU2411328C1 - Prefabricated reinforced concrete frame of multistory building of higher fire resistance - Google Patents

Abstract

FIELD: construction. ^ SUBSTANCE: prefabricated reinforced concrete frame of multistory building includes columns and crossbars of T-shaped section hingedly connected to them in level of slab to form closed cells, and slab flooring made of hollow prestressed boards. Columns in lower floors are made with longitudinal reinforcement arranged in at least two rows, with height for several floors, and with sockets at slab level, where metal wedging cantilevers are mounted for support and tightening with bearing crossbars, and are connected to each other with displacement from top of boards by 1/2-1/4 of floor height by means of flat joint. Lower end of column includes joint metal plates with holes for reinforcement protrusions, and at the angles there are slots framed with vertical metal plates. Upper end of column includes extensions of reinforcement arranged in holes of lower end of upper column, at the same time reinforcement extensions are equipped with adjustment nuts to make it possible to change thickness of seam, with each column the following components are fixed in orthogonal directions - at least one wide prestressed bearing crossbar, forming closed cell, with provided one or two shelves for rest of slab floorings, bearing walls with height of one floor, mounted with support one onto another via contact joint and rigidly connected to each other and to columns, at the same time bearing crossbars are arranged with lower shelves and inclined walls, cut at the same angle near columns, forming rigid contact joints in plane of slab, besides, bearing crossbars have vertical slots, and walls - slots and/or through holes within thickness of slab board to make keys as joints of connection of bearing crossbars and walls with slab boards are concreted. ^ EFFECT: reduced time of construction, lower material intensity and labour intensiveness in manufacturing and assembly and increased fire-resistance of building. ^ 9 dwg

Description

The invention relates to the construction, namely, to the designs of reinforced concrete frames with increased fire safety requirements.

A typical prefabricated frame frame II-20 for industrial buildings is known, including columns with trapezoidal consoles for supporting ⊥-shaped crossbars, on the shelves of which ribbed plates are laid. /one/

The disadvantage of this solution is the presence of consoles of columns protruding downward, shelves of crossbars and plate edges, which is inconvenient for civil buildings, as well as high labor costs and steel consumption in crossbars, plates and in the frame junction of crossbars with columns.

A typical communication frame of the 1.020.1 / 83 series is known, including columns with countersunk consoles, on which ⊥-shaped crossbars are supported. Crossbars and hollow slabs are pre-stressed, and the joint of crossbars with columns is hinged. / 2 /

The disadvantages are the presence of crossbars in only one direction and the insufficient strength, rigidity and fire resistance of the bonded floor slabs, the limited planning capabilities of the frame due to the protruding shelves of the crossbars.

Known frame in two directions frame IIS-04 for buildings up to four floors in height, including, along with crossbars installed in one direction, and connecting beams installed in the other direction. In this case, the crossbars and beams form closed cells of the overlapping disk, filled with prefabricated floorings from hollow slabs. / 3 /

However, the rejection of wall-diaphragms reduces the spatial rigidity of the frame and the number of storeys of the building, and the absence of lower shelves and key couplings in the connecting beams precludes their joint work with the flooring and reduces the strength and rigidity of the plates and crossbars.

Known precast-monolithic frame, composed of vibropressed pre-stressed non-cantilever columns, the length of which corresponds to the height of the floor with through openings at the level of ceilings, monolithic longitudinal and precast monolithic transverse beams, the latter are formed from a lower pre-stressed vibropressed reinforced concrete formwork beam with symmetrical relative to it protrusions and reinforced monolithic top. Vibro-pressed multi-hollow reinforced concrete slabs rest on the protrusions. The width of the upper monolithic and lower assembly parts of the transverse crossbars is wider than the adjoining face of the columns. /four/

The closest is a precast-monolithic reinforced concrete frame of a multi-storey building, including non-cantilevered multi-storey columns of constant square section with through holes at the level of the floors, hingedly connected to them at the level of the overlap with the formation of closed cells, the prefabricated monolithic bearing and communication crossbars with the lower assembly element of the T-section and flooring of hollow prestressed slabs laid in a cell with a gap between each other, and monolithic concrete of connection nodes, hole thi and seams. /5/

The disadvantages of the known skeletons of multi-storey buildings include the large number of time-consuming joints of columns in multi-storey buildings, the difficulty of monolithic through openings in the columns and the need to strengthen these places during transportation and installation of multi-storey columns, high consumption of monolithic concrete in the crossbars, insufficient height and rigidity of the main and connecting crossbars , insufficient fire resistance of the structure, metal-intensive and labor-intensive frame joint of crossbars with columns, increased material consumption.

The technical task is to reduce construction time, reduce the complexity in the manufacture and installation and material consumption by manufacturing linear frame elements (plates, beams and columns) on long formwork stands and create a precast reinforced concrete frame with the maximum reduced floor height due to the protruding shelves of the crossbars and expanding the space-planning capabilities while eliminating the welding of joints, reducing the weight of the fittings and the metal-intensive technological and rigging, abandonment of the steel mold park at the plant, while ensuring the strength and stability of multi-story buildings with vertical, wind and fire effects.

The solution to this problem is achieved due to the fact that in a precast concrete frame of a multi-storey building of increased fire resistance, including columns of constant square section, pivotally connected to them in the level of overlap with the formation of closed cells of the crossbar of the t-section and flooring from hollow prestressed plates laid in the cell with a gap between themselves, and the concrete of monolithic joints and joints, according to the invention, the columns in the lower floors are made with longitudinal reinforcement, placed at least in two rows, several stories high with nests in the level of overlap, in which metal proppant consoles are mounted for support and retraction with load-bearing crossbars and are interconnected with an offset from the top of the plates by 1 / 2-1 / 4 of the floor height by means of a flat joint, at the same time, docking metal plates with holes for rebar outlets are placed at the bottom end of the column, and grooves bordered by vertical metal plates are made at the corners, reinforcement outlets are located at the top end of the column, times placed in the holes of the lower end of the upper column, while the valve outlets are equipped with adjusting nuts for the possibility of changing the thickness of the seam, each column is connected in orthogonal directions with at least one wide prestressed load-bearing crossbar, forming a closed cell, with one or two shelves for supporting the decks ceilings, bearing walls one floor high, mounted with support on each other through a contact joint and rigidly interconnected and with columns, while supporting crossbars made with lower shelves and inclined walls, cut at the same angle at the columns, forming rigid contact joints in the floor plane, the bearing crossbars having vertical grooves, and the walls with grooves and / or through openings within the thickness of the floor slab for forming dowels when monolithic with concrete connection points of bearing crossbars and walls with floor slabs.

The proposed prefabricated frame is characterized in that the columns in the lower floors are made with longitudinal reinforcement placed in at least two rows, several floors high with nests in the level of overlap, in which metal wedging consoles are mounted for support and retraction with load-bearing crossbars and connected between with a offset from the top of the plates by 1 / 2-1 / 4 of the floor height by means of a flat joint, while in the lower end of the column there are docking metal plates with holes for the outlets of the fittings, and at the corners s, bordered by vertical metal plates, in the upper end of the column are the outlets of the fittings located in the holes of the lower end of the upper column, while the outlets of the fittings are equipped with adjusting nuts for the possibility of changing the thickness of the seam, at least one wide pre-tensioned supporting beam is connected in orthogonal directions forming a closed cell, made with one or two shelves for supporting flooring, bearing walls one floor high, mounted supported on each other through a contact joint and rigidly connected to each other and to the columns, while the bearing crossbars are made with lower shelves and inclined walls cut at the same angle at the columns, forming rigid contact joints in the plane of overlap, and the bearing crossbars have vertical grooves and the walls - grooves and / or through openings within the thickness of the floor slab for the formation of dowels when monolithic with concrete the nodes of the connection of the load-bearing crossbars and walls to the floor slabs.

Reducing the height of the crossbar with a decrease in the height of the shelves is achieved due to the tension of the reinforcement, joint work with the plates, the conditionally articulated joint of the crossbars with columns and the support of the flooring on three or four sides on the crossbars and walls.

The exception of welding at the joints of columns and crossbars is provided by means of a flat joint of columns and a conditionally articulated joint of a crossbar with columns.

The spatial rigidity of the frame simultaneously from the action of vertical and wind loads is ensured by vertical abutments consisting of load-bearing walls rigidly combined with columns and horizontal floor disks.

The strength and stability of the columns under the simultaneous impact of vertical loads and fire is ensured by:

- fastening columns in the longitudinal and transverse directions with crossbars and walls;

- ensuring rigidity in the horizontal plane of the floor cells even without decking due to the large width of the crossbars and the large rigidity of their monolithic contact joints around the columns when trimming shelves and walls at the ends at the same angle of 45 °;

- arrangement of working fittings in columns and crossbars in two or three rows and a large width of crossbars.

Figure 1 presents the plan of the precast concrete frame of a multi-storey building; figure 2 - prefabricated column; figure 3 - section 1-1 of figure 2; figure 4 is a vertical section at the junction of the columns; figure 5 - 1-1 figure 1; 6 - 2-2 of figure 1; Fig.7 - the junction of the columns and walls; Fig.8 - 3-3 of Fig.1; Fig.9 - 4-4 of Fig.1.

The prefabricated reinforced concrete frame of a multi-storey building with increased fire resistance consists of multi-storey vertical load-bearing columns 1 of constant square cross-section along the building height, load-bearing walls 2 and load-bearing crossbars 3. Load-bearing crossbars 3 and walls 2 connect columns 1, forming closed horizontal cells filled with flooring 4 from hollow reinforced concrete slabs 5, supported in the end 6 and longitudinal 7 mates along the contour of the load-bearing crossbars 3 and walls 2 (figure 1).

Multistory square columns with faces with a width of "b" have at the level of the overlap sockets 8 for installation on the installation of metal consoles 9 (figure 2). At the ends of the columns are equipped with metal plates 10 for the device of flat joints 11, made above the ceiling to a height of not more than half and not less than a quarter of the height of the floor (figure 2, 3, 4). The column is reinforced with vertical reinforcement 12. To increase the fire resistance and provide spatial rigidity of the frame without the participation of floor slabs, the supporting crossbars 3 are installed in two directions with the lower tensile reinforcement 13 located in three rows (Fig. 9), except for the reinforcement 12 located in the corners, the rest the longitudinal reinforcement of the columns 14 is shifted in depth, in the second and third rows (figure 3).

To join the columns, four rods 12 were threaded from the corners of the upper ends, and holes 15 were made at the corners of the columns in the upper ends of the columns 15 and grooves 16 were arranged, bordered by vertical and horizontal 17 plates, to allow the rods 12 to pass through and tighten the tightening nuts 18 and aligning the joint thickness of 11 nuts 19, while the vertical plates 17 are anchored in the concrete of the columns above the horizontal plates 17, where they are welded with the longitudinal working rods of the 14 columns (Figs. 2, 3, 4).

The walls 2 are supported in height on each other through the contact seam 20 (Figs. 5, 6), and with columns 1 and with each other they are combined in vertical mates 21 using metal joints 22 in an amount of at least two and no more than four pieces within the height of the floor (Fig.7), while the walls 2 have shelves 23 of height h, not protruding beyond the edges of the columns 1, with a departure a≥h (Fig.6). Flat crossbars 3 with height h _p ≤b, width at the top equal to b _at ≤2h _p , and at the bottom - b _n ≤3h _p , with lower shelves 24 with height h _p (Fig. 8), as in a wall, while the supports of the shelf and the walls of the crossbars are cut at an angle of 45 ° and at the ends the width of the crossbars is equal to the width of the face of the columns b (Fig. 1), in the extreme supported plate of the flooring there is no one or more extreme voids.

Multi-hollow plates 5 are supported on shelves 23 and 24 of walls and crossbars with ends 25 or extreme ribs 26 that are significantly thicker than average 27, while the height of the plates is greater than the height of the wall 28 of the crossbars by δ≥δ _{p of the} thickness of the upper shelf 29 of the plates for convenience pass bent reinforcing ties 30, anchored at the ends of the voids 31 of the plates (Fig), and ties-frames 32, anchored in mezhplitnyh seams 33 (Fig.9).

To ensure the strength and rigidity of the overlap disk in the vertical and horizontal planes of the walls 28 of the crossbars 3, vertical grooves 34 are made, and the plugs 35 are installed in the ends of the voids 31, so that after monolithic end mates 6 concrete keys are formed in them, while the grooves in the middle part of the walls of the crossbars are absent so as not to weaken the compressed zone of the wall of the crossbars, and grooves 34 or through openings 36 are made in the walls at the level of the plates.

Information sources:

1. Banks V.N., Sigalov E.E. "Reinforced concrete structures", M., SI, 1985.

2. Dovgalyuk V.I. “Connection of prefabricated reinforced concrete frame structures of buildings”, Obzor, M., VNIINTPI, 1989

3. Kazina G.A. "Modern reinforced concrete structures of earthquake-resistant buildings." Review, M., VNIIS, 1981

4. RF patent No. 2233952, MKI E04B 1/18, publ. 08/10/2004

5. SU No. 1776734, MKI E04B 1/18, 12/23/93, BI No. 43 (prototype).

Claims (1)

Prefabricated reinforced concrete frame of a multi-storey building with increased fire resistance, including columns of constant square cross-section, articulated to them in the level of overlap with the formation of closed cells of T-section crossbars and flooring of hollow prestressed slabs laid in the cell with a gap between themselves, and concrete monolithic connection nodes and seams, characterized in that the columns in the lower floors are made with longitudinal reinforcement placed in at least two rows, several floors high with dams in the level of overlap, in which metal proppant consoles are mounted for support and retraction with load-bearing crossbars and are interconnected offset from the top of the plates by 1 / 2-1 / 4 of the floor height by means of a flat joint, while metal docking joints are placed at the bottom of the column plates with openings for the outlets of the reinforcement, and grooves bordered by vertical metal plates are made at the corners, reinforcement outlets located in the openings of the lower end of the upper column are located at the upper end of the column, while the valve outlets are equipped with adjusting nuts for the possibility of changing the thickness of the seam, with each column connected in orthogonal directions at least one wide pre-stressed load-bearing beam, forming a closed cell with one or two shelves for supporting the flooring with one-story load-bearing walls mounted with a support each other through a contact joint and rigidly interconnected and with columns, while the bearing crossbars are made with lower shelves and inclined walls, cut at the same angle at the columns forming rigid contact joints in the floor plane, with the bearing crossbars having vertical grooves and the walls with grooves and / or through openings within the thickness of the floor slab to form dowels when monolithic in concrete, the monolithic joints of the bearing crossbars and walls with plates overlap.

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