RU2490403C1 - Method to increase bearing capacity of jointless monolithic reinforced concrete frame - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method includes connection of pillars with floor slabs and placement of reinforcement elements. Forces are redistributed in areas of pillars coupling with slabs, forming single structural element units. The conventional borders of element units in plan are lines of rated zero bending torques in slabs around pillars. The conventional borders of element units along the vertical line are cross sections of pillars arranged in the middle of floor height. The design of the element unit sets eccentricity of vertical load transfer to pillars. The frame is formed from single structural element units, combining them into a spatial frame with reinforcement that is continuous and loopback in radial directions via adjacent slabs and pillars.

EFFECT: provision of higher bearing capacity of a frame.

7 dwg

Description

A method of increasing the bearing capacity of a bezelless monolithic reinforced concrete frame relates to the field of construction and can be used in the construction of housing, cultural, domestic and industrial facilities, including with spans of floors of more than 9 meters, with various types of column sections, in high-rise monolithic construction , including in areas with increased seismic activity.

Known are traditional methods of assembling reinforced concrete bezelless frames from columns and flat floors, at the intersection of which, as a rule, the reinforcement of the columns is not connected with the reinforcement of the floor. As a result, in order to increase the load-bearing capacity of the carcass, during load perception, with an increase in the size of the span of the ceiling, the thickness of the slab and / or the cross-section of the column is increased, as well as densely reinforced near-wall zone of overlap.

It is known that during concreting, as a rule, the joints are located at the level of the upper and lower planes of the floor slab, that is, the plates intersect with the concreting of the column.

It is known that the joint of the longitudinal reinforcement of the columns is carried out mainly with an overlap in the body of the column, which leads to useless overuse of the reinforcement, especially with an increase in the diameter of the reinforcement.

If, with the traditional reinforcement system, with increasing column spacing and floor loads, with a column cross-section of 400 × 400 and a plate thickness of 200 mm, as a result of the calculation, we obtain the calculated reinforcement in the upper stretched zone of the floor slab: Ax + Ay = 100 cm ² , where Ax, Ay are the calculated values of the reinforcement in mutually perpendicular directions, it is simply impossible to place such an amount of reinforcement in the stretched zone of the plate.

The well-known "Method of erecting a frame of a bezelless multi-storey building" according to the patent RU 2134752 from 01/21/1998, published on 08/20/1999, IPC ⁶ E04B 1/18, which consists in the installation of ordinary and external columns, the installation of supercolumn floor slabs on them, and the installation of intercolumn and central floor slabs, in this case, after installing the ceiling of the upper floor of the building on the upper floor or on the upper floors, diagonal braces are additionally mounted, connecting the bottom of the outer columns within the top of each of these floors with the top of adjacent ordinary columns or the top of columns with the bottom of adjacent ordinary columns and located normally to the building facade corresponding to them, and then part of the outer columns placed under the diagonal struts within the first floor is removed.

This method is difficult to use due to additional struts, and does not allow to erect buildings with large spans of floors.

The well-known "Method of erecting a bezelless building frame" according to patent RU 2206674 from 10/11/2001, published on 06/20/2003, IPC ⁷ E04B 1/18, E04B 1/22, including the installation of columns and floor slabs, monoling joints between columns and plates, the passage of reinforcement through the columns between the slabs in mutually perpendicular directions and tensioning it, holding until the concrete sets the joint between the columns and slabs of the transmission strength, followed by the transfer of the tensile force to the concrete along the perimeter of the building and the monolithic joints between the slabs, after which the concrete is set the joint between the columns and the plates of the transmission strength, the tension force of the reinforcement on the concrete is transferred alternately in mutually perpendicular directions in stages - first 30-40% of the total tension force, then 60-75% of the total tension force, followed by a complete release of tension.

This method is also difficult to use due to the fact that it requires additional tension of the reinforcement on concrete, and there is no constructive connection of the columns with the ceiling.

The closest is the "Method of increasing the bearing capacity of bezbolnogo monolithic reinforced concrete floors" according to patent RU 2394140, dated 09.06.2009, published July 10, 2010, IPC E04G 23/02, EB04 5/43, including placement on a floor slab connected to the column, which is equipped with longitudinal reinforcement of reinforcing elements, while vertical holes are made in the near-slab zone of the floor slab, into which reinforcing elements are installed in the form of a set of rods with anchor elements at the ends forming non-longitudinal reinforcement th transverse reinforcement, and pour the solution with a non-shrinking expanding concrete mixture; the near-sided overlapping zone of the placement of vertical rods of the transverse reinforcement in the plan has the shape of four rectangles, one side of each of which adjoins the column and is equal to the width of the latter, and the other side exceeds 1.5-3.5 times the thickness of the slab; the diameter of the holes made in the slab is 1.5-2.5 times larger than the diameter of the rods of the transverse reinforcement, while the holes on the bottom are made blind with a bottom or equipped with a stopper; the near-column zone of overlapping the placement of vertical rods of transverse reinforcement in the plan has the shape of a square described around the column, the side of which is equal to the sum of the column width and twice the determining size of the near-column zone - the distance between the external boundary of the near-column zone and the column exceeding 1.5-3.5 times the thickness floor slabs.

This method of increasing the bearing capacity of a bezel-free monolithic reinforced concrete floor reinforces only the near-column part of the floor and only additional transverse reinforcement, without creating a single node for connecting the column to the floor.

The objective of the proposed technical solution is to provide increased load-bearing capacity of a monolithic reinforced concrete frame during the construction of housing, cultural, domestic and industrial facilities, including with spans of floors of more than 9 meters, without prestressing reinforcement, with various types of column sections, in a monolithic high-rise construction, including in areas with increased seismic activity.

The problem is solved by a method of increasing the bearing capacity of a bezelless monolithic reinforced concrete frame, including connecting columns with floor slabs, and the placement of reinforcing elements, while increasing the carrying capacity of the frame by redistributing forces in the places where the columns mate with floors, creating single structural units, the conditional boundaries of which are, on the plan, the lines of the calculated zero bending moments in the ceilings around the columns, and the vertical sections of the columns located in gray uniform height of floors; the design of the element-unit sets the eccentricity of the vertical load transfer to the columns; they form a frame from unified structural element-nodes, combining them into a spatial frame continuous and looped in radial directions, through adjacent ceilings and columns, by reinforcement.

A method of increasing the bearing capacity of a bezrigelny monolithic reinforced concrete frame, by redistributing the forces at the mating places of the columns with ceilings, allows to increase the resistance to mutual rotation of the columns and ceilings at the mating places, and to increase the rigidity of the frame in all directions; increase resistance to horizontal loads, such as wind and ripple; adjustable eccentricity "e" to start the mechanism of automatic unloading of columns; perceive bending moments from wind and flying loads as a single unit-node with a height of an entire floor, and not separately by a column and ceiling; redistribute the force of pushing the ceiling over the column, since the ceiling does not feel support on the column, but on a significantly expanded area, due to the special configuration of the reinforcing bars in it, since the bends of the longitudinal reinforcement of the lower column, resting against the bends of the longitudinal reinforcement of the upper column, create the effect of supporting capitals in the body of the plate, at the same time, being reliable anchors in the perception of bending, near-moment moments; increase the seismic resistance of the frame.

A method of increasing the bearing capacity of a bezelless monolithic reinforced concrete carcass is carried out in the carcass shown in the drawings, where in Fig. 1 is a complete assembly, in Fig. 2 is a monolithic structural element, a unit with reinforcement 9, in Fig. 3 - reinforcement 9, 17, 18 ; figure 4 is a structural section along the frame, figure 5 is the layout of the reinforcement in terms of overlap, figure 6 is a monolithic structural unit with reinforcement 18, figure 7 is an arrangement of equidistant columns on the principle of an equilateral triangle.

9 колонной части узла с отгибами в плитную часть узла, растянутая приколонная зона 10 плитной части узла, зона 11 плиты перекрытия, растянутая пролетная, арматура 12 конструктивная, стык 13 отогнутой части продольной арматуры колонной части элемента-узла в верхней растянутой приколонной плитной части элемента-узла, консольные свесы 14 перекрытия, кольцевая распределительная арматура 15, эксцентриситет «е» 16 передачи нагрузки перекрытия на колонну, продольная арматура

17 колонной части узла с отгибами в плитную часть узла, продольная арматура

18 колонной части узла с отгибами в плитную часть узла, колонная часть 19 элемента-узла, плитная часть 20 элемента-узла.Figure 1, 2, 3, 4, 5, 6, 7 show: frame 1 monolithic reinforced concrete bezelless assembly, rigid structural element-unit 2, column 3, overlap 4, line 5 of the calculated zero bending moments in the floors, section 6 columns with the least bending moments, the location of the concreting joints, reinforcement 7 radial overlap, reinforcement 8 concentric, longitudinal reinforcement

9 of the column part of the assembly with bends into the plate part of the assembly, the extended near-edge zone 10 of the plate assembly, the zone 11 of the floor slab, the extended span, structural reinforcement 12, the joint 13 of the bent portion of the longitudinal reinforcement of the column part of the assembly-unit in the upper stretched near-wall plate part of the element - node, cantilever overhangs 14 overlap, annular distribution fittings 15, eccentricity "e" 16 transfer load floor to the column, longitudinal reinforcement

17 column part of the assembly with bends in the plate part of the assembly, longitudinal reinforcement

18 column part of the assembly with bends in the plate part of the assembly, column part 19 of the assembly member, plate part 20 of the assembly member.

A method of increasing the bearing capacity of bezrigelnogo monolithic reinforced concrete frame is carried out during its assembly as follows.

Install the formwork of the floor 4 of the current floor. Under this formwork, sections of the castle formwork are installed on the upper part of the columns, from section 6 of the current floor.

A structurally organized element-node 2 is formed from the column part 19 and the plate part 20, around the center located at the intersection of the central axis of the column 3 with the floor slab 4, vertically - from the half of the column of the current floor and half of the column of the next floor, with conditional boundaries along the section of 6 columns located in the middle of the height of the floors, and on the plan - from a fragment of the overlap around the columns, with conditional boundaries along the line of 5 calculated zero bending moments in the ceilings, matching the plate and column parts, combined radially directed longitudinal reinforcement of 9, or 17, or 18 columns, by bends to the plate part of the assembly element, while creating conditions for the redistribution of force in the places where the columns mate with the ceilings, increasing the bearing capacity of the frame.

9,

17,

18, является основной образующей арматурного каркаса элемента-узла 2.Reinforcement with a special configuration of bends

9,

17,

18, is the main generatrix of the reinforcing cage of the element-node 2.

In the stretched near-zone zone 10 of the slab part of the element-node 2, the reinforcement 9, and / or 17, and / or 18, by bends for the lower and upper floors, are rigidly connected to the vertical overlap.

The presence of reinforcement 9, 17, 18, bends in the upper elongated near-zone zone 10 of the slab part of the element-node 2, defines, always present and regulated by design solutions, the eccentricity "e" 16, the transmission of the vertical load of the ceiling to the column.

The presence of eccentricity "e" 16 transfer of vertical load to the column part 3 of the element-node 2, with a rigid joint 13 and a curved shape of the part 9 or 17 or 18:

- creates a moment in the column part of the valve 9 or 17 or 18, pulling the valve up, that is, in the valve 9 or 17 or 18 creates an unloading column 3 force directed upward;

- provides automatic operation of the unloading mechanism: with an increase in the number of floors, the unloading moment in the columns of 3 underlying floors also increases.

The assembled spatial reinforcing cage for forming the element-node 2 is set with its bends of the reinforcement 9, and / or 17, and / or 18, on the same spatial reinforcing cage protruding from the column 3 of the current floor, on the bends of the reinforcement 9, and / or 17, and / or 18,

Bends of the longitudinal reinforcement 9, or 17, or 18, of the lower column (FIG. 2, FIG. 4, FIG. 6), abutting against the limb of the longitudinal reinforcement 9 or 17 or 18 of the upper column (FIG. 2, FIG. 4, FIG. 6) create the effect of supporting capitals in the body of the plate, at the same time being reliable anchors in the perception of bending near-face moments. At the same time, the overlap during operation does not feel support on the column, but on a significantly expanded area.

Bends are welded in the overlap of reinforcement 9, and / or 17, and / or 18, of the current and next floor. Next, the radial reinforcement 7 is laid out, welding it with the reinforcement 9, or 17, or 18, (Fig. 2), the concentric reinforcement 8 is installed in the span of the ceiling (Fig. 2, Fig. 6), and the structural reinforcement 12, that is, form a frame from unified structural elements-nodes, combining them into a spatial framework continuous and looped in radial directions, through adjacent floors and columns, by reinforcement, creating a continuous column-ceiling-column-ceiling system, looped by adjacent ceilings and columns of radial reinforcement m (see FIG. 4).

Then, formwork sections of columns 3 are installed on half of the next floor and the floor 4 of the current floor is concreted with half of the column 3 of the current floor and half of the column 3 of the next floor, that is, the elements-nodes 2 are concreted as a whole in one grip between the sections of 6 columns located in the middle of the height of the floors 3, which dramatically increases the bearing capacity of the frame.

The bearing capacity of bezrigelnogo monolithic reinforced concrete frame increases with the operation of the element-node 2, as follows.

The main characteristic of the element-node 2 is the eccentricity "e" 16 transfer load overlap on the column.

Span vertical loads acting on the ceiling are transmitted through reinforcement 9 or 17 or 18 to column 3 with eccentricity "e" 16. Moreover, in addition to compression force N, tensile forces from bending moment equal to M arise on each floor in the longitudinal reinforcement of columns = Ne. (figure 4)

Due to the presence of eccentricity 16 and continuity, ringing with the adjacent floor of the radial reinforcement column-floor-column-column-floor, (Fig. 4) span loads on the floor stretch the radial reinforcement, including in the column zone, creating a discharge moment in the column reinforcement . Given this, it is possible to reduce the cost of reinforcing columns.

Moreover, with the same parameters of the floors and loads and eccentricities, compression forces сжатияN = nN and bending moment ∑M = nNe, where n is the number of floors, will appear in the reinforcement of the columns of the lower floor.

If, in the traditional method of assembling the frame, the bending moment above the column did only destructive work, then in the proposed technical solution, the bending moment M created by the eccentricity "e", due to the special shape of the reinforcement 9 or 17 or 18, tends to pull the reinforcement up, that is, it creates vertical force directed upward, and opposite to the vertical load on the frame.

Due to this, the self-unloading effect in the columns constantly works in the frame, and with the increase in the number of floors, the unloading effect also automatically increases in the lower floors.

Due to the vertical overlap of the bends of the longitudinal reinforcement 9, or 17, or 18, of the columns 3, in the elongated near-edge zone 10 of the plate part of the element-node 2, additional rigidity of the reinforcement section is created when perceiving the bending moment (Fig. 4).

Due to the rigid joint 13 of the bends of the longitudinal reinforcement of the columns and its further branching into columns of the upper and lower floors, the bending moment increases in the direction from the joint 13 to the column 3, due to an increase in the distance between the sections of the bends 9 of the upper and lower columns.

A method of increasing the bearing capacity of a bezrigelny monolithic reinforced concrete frame by redistributing the forces in the places of conjugation of columns with ceilings allows:

- increase the resistance to mutual rotation of the elements (columns and ceilings) in the interface and increase the rigidity of the frame in all directions;

- increase resistance to horizontal loads (wind, ripple);

- adjustable eccentricity "e" to start the mechanism of automatic unloading of columns;

- redistribute the bending moments of the ceilings, which are no longer perceived by the column, but by the element-node, and redistribute the force of forcing the overlap over the column, since the overlap feels support not on the column, but on a significantly expanded area, due to the special configuration of the reinforcing bars in it, since bends of the longitudinal reinforcement of the lower column (FIG. 2, FIG. 4, FIG. 6), abutting against the bends of the longitudinal reinforcement of the upper column (FIG. 2, FIG. 4, FIG. 6) create the effect of supporting capitals in the body of the plate, at the same time being reliable mi anchors in the perception of bending funnel moments.

The technical effect is to provide increased load-bearing capacity of a monolithic reinforced concrete frame during the construction of housing, cultural, domestic and industrial facilities, including with spans of floors of more than 9 meters, without prestressing reinforcement, with various types of cross-sections of columns, in high-rise monolithic construction, including including, in areas with increased seismic activity, by redistributing efforts at the places where the columns mate with the ceilings, creating unified structural elements-nodes, conditional groups whose names are, on the plan - lines of calculated zero bending moments in the ceilings around the columns, and vertically - sections of columns located in the middle of the height of the floors; the design of the element-unit sets the eccentricity of the vertical load transfer to the columns; they form a frame from unified structural elements-units, combining them into a spatial frame continuous and looped in radial directions, through adjacent ceilings and columns, by reinforcement.

Claims (1)

A method of increasing the bearing capacity of a bezrigelny monolithic reinforced concrete frame, comprising connecting columns with floor slabs and placing reinforcing elements, characterized in that they increase the carrying capacity of the frame by redistributing forces at the mating places of the columns with floors, creating uniform structural units, the conditional boundaries of which are on plan of the line of calculated zero bending moments in the ceilings around the columns, and vertically - sections of the columns located in the middle of the height tazhey; the design of the element-unit sets the eccentricity of the vertical load transfer to the columns; they form a frame from unified structural elements-units, combining them into a spatial frame continuous and looped in radial directions through adjacent ceilings and columns with reinforcement.

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