RU2281362C1 - Composite reinforced concrete multistory building frame - Google Patents

Abstract

FIELD: building, particularly to erect multistory buildings.

SUBSTANCE: building frame comprises composite reinforced concrete columns with orifices made at floor panel levels and curvilinear channel formed in lower part of column sections corresponding to building stories. The frame also has composite girders with protruded reinforcement bars extending from upper edge and ends thereof, rectangular indents made in upper face of support part adapted to receive erection support reinforcement, hollow floor panels including round channels and having end surfaces inclined at 14-16° angles to panel plane along the full end surface heights. Reinforced concrete columns extend for several building stories and have different cross-sections, namely square, rectangular and angle-shaped cross-sections made so that basic core of section is retained and predetermined number of reinforcement bars are included in core of section. The columns are connected with each other along building height by means of plug connections. Column ends are provided with protruded reinforcement bars and with depressions adapted to receive protruded reinforcement bars. Frame members are connected with each other after support reinforcement laying and connection with collars located across the width of composite girder and by grouting upper edge of composite girder to fill column orifices with concrete.

EFFECT: increased efficiency and possibility to improve building appearance, increased frame rigidity at frame assemblage stage, enhanced technological efficiency of frame assemblage and reduced labor inputs for floor panel manufacturing.

4 cl, 23 dwg

Description

The invention relates to the field of construction and can be used in the construction of residential and public buildings with high floors.

Known prefabricated monolithic frame of a multi-storey building (patent of the Russian Federation No. 2087633, 08.20.1997, class E 04 B 1/18), including precast concrete columns with holes and floor slabs, supported by two opposite ends on the joints between them, forming closed into columns crossbars, the upper rods of the multi-row reinforcement of which are monolithic in the holes of the columns. The monolithic crossbar, whose concrete fraction per unit area of the overlap is about 33%, is made without prestressing, which limits the dimensions of the spans and, consequently, the planning possibilities. The fixed number of holes in the columns and the presence of three types of sections of a monolithic crossbar depending on the acting loads leads to an increase in the formwork sizes of the columns and limits the possibility of changing the number of bars of the working reinforcement.

The frame of a multi-storey building and the method of its construction are known (copyright certificate AS SU 1776734 A1, 11/23/1992, class E 04 B 1/18), including columns with openings of rectangular cross-section located along one of the central axes of the columns in the level floor slabs installed with gaps between their faces, and prestressed reinforcement length and width of the building, placed in the gaps between the floor slabs, passed through the openings of the columns, anchored around the perimeter of the building and monolithic with concrete to form a collection o-monolithic crossbars in two mutually perpendicular directions, one of which is disposed coaxially with the rectangular holes of the columns and have a width less than the width of the latter. The described structural scheme involves the installation of reinforcement used as prestressed, but without explanation, how the tension of this reinforcement will be made. In addition, monolithic crossbars located in two mutually perpendicular directions and made of monolithic concrete within the height of the prefabricated floor slab, have reduced stiffness and lead to the operation of prefabricated floor slabs, monolithic together with the crossbars, in two directions, while the reinforcement of the slabs involves their work in one direction. In the proposed structural scheme, the proportion of monolithic concrete per unit area of the overlap is about 15%.

The closest in purpose and effect achieved is the precast-monolithic reinforced concrete frame of the multi-storey building "KAZAN-1000" (patent of the Russian Federation No. 2184816, 06/10/2002, class E 04 B 1/20), including prefabricated reinforced concrete columns with holes, prefabricated tensioned crossbars with horizontal recesses of a triangular section on the end faces and round hollow floor slabs with a gap between their ends made oblique to the plane of the plate with an angle of inclination of 25-30 °, while the gaps between the ends of the plates and the holes in lonnah hardwired together with issued them rebar prefabricated frame elements.

The disadvantages of the precast-monolithic frame of the multi-storey building "KAZAN-1000" found in the design and installation process are:

- the impossibility due to the constant size of the cross-section of the columns along the height of the building to significantly increase their bearing capacity by installing additional reinforcing bars, the number of which according to the features of the frame should be four;

- the impossibility of a simple increase in the cross section of the columns, since this will entail an increase in the wall thickness and, as a result, loads on the building as a whole, and when applying a smaller thickness of the outer wall of the column, they will go out of the plane of the outer wall into the building, which leads to a decrease in the aesthetic attractiveness of the premises, especially in residential multi-story frame buildings, where the columns should be hidden in the thickness of the outer wall;

- reduced rigidity of the frame at the installation stage, which leads to the formation of initial cracks in the nodes of the crossbars with columns and, as a result, to a decrease in the rigidity of the building frame as a whole;

- an unacceptable error in the installation of the supporting reinforcement of the monolithic part of the crossbar due to the complexity of the device for releasing the reinforcement from the precast crossbar at the same level, which leads to a mismatch in the design location of the supporting reinforcement and, accordingly, to a possible decrease in the bearing capacity of the precast monolithic crossbar

- increased complexity in the manufacture of hollow core slabs in the device part of the inclined end surface of the slab at half its height, which leads to partial collapse of concrete after removal of the hollow formers and to reduce the reliability of the structure as a whole.

The invention is aimed at creating a constructive frame system for the construction of buildings with increased number of storeys, while ensuring high reliability by improving the interfaces of the frame elements, the increased rigidity of the frame at the installation stage, the high manufacturability of the frame assembly, the reduction of laboriousness in the manufacture of floor slabs and the aesthetic attractiveness of residential premises.

The result is achieved in that in the precast-monolithic reinforced concrete frame of the multi-storey building "KAZAN-XXIв", consisting of prefabricated reinforced concrete columns with holes in the level of the floors, pre-assembled prestressed crossbars with reinforcement outlets on the upper face and at the ends having horizontal recesses on the end faces triangular cross-section, hollow-core slabs with a gap between their ends, which together with the holes in the columns are monolithic at the same time as the reinforced outlets from prefabricated elements released into them the frame according to the invention, reinforced concrete columns running on several floors have different cross-sectional shapes - square, rectangular and angular, while maintaining the base size of the core section and a fixed number of reinforcing bars (4 pcs.) within the base core, crossbars on the upper face of the support the parts have rectangular frames for laying the mounting support reinforcement, and the end surfaces of the round hollow floor slabs are made inclined to the plane of the slab over its entire height with an inclination angle of 14 ÷ 16 °.

The result is also achieved by the fact that the column joint in height is made in the form of a plug connection in the middle zone of the floor section of the columns, while the ends of the columns have outlet fittings and grooves where these outlet fittings enter, but to maintain the uniformity of the junction of the columns of various cross-sectional shapes within the base size of the core, the rebar releases and grooves are made respectively at the lower and upper ends of the column, and vice versa outside the base core, i.e. releases of fittings and grooves are made, respectively, at the upper and lower ends of the joined columns.

The result is also achieved by the fact that in order to fill the gap formed under the lower plane of the floor section of columns after monolithic frame elements, a curved channel is made in the lower part of each floor section of columns connecting the lower horizontal plane of the floor section of the column with its lateral plane.

The result is also achieved by the fact that the loop outlets of the transverse reinforcement in the supporting part of the prefabricated crossbar located along the width of the crossbar must be arranged along the length of the crossbar in two rows and combined with loop clamps located across the width of the crossbar.

The invention is illustrated in the drawings. Figures 1 and 2 show fragments of the layout of columns of different cross-sectional shapes, respectively, on the lower and upper floors. Figure 3 ÷ 7 shows the layout of the columns, and figure 10 ÷ 15 joints of columns with different shapes of the cross section along the height of the building. On Fig and 9 shows a diagram of the execution of the channel to fill the gap under the lower plane of the floor section of the columns after monolithic elements of the frame. On Fig.16 ÷ 20 shows the characteristics of the formwork forms of prefabricated crossbars and floor slabs. On Fig.21 ÷ 23 shows the nodes of the pair of frame elements.

Columns 1, 2, 3 have openings 4, dividing the body of the column into separate sections with a step to the floor. The cross-sectional shape of the columns is made of three types: rectangular 1 and angular 2 for the lower floors, which are characterized by a high level of longitudinal forces, and square 3 for the upper floors, where the level of longitudinal forces is insignificant. At the same time, in order to ensure the same type of coupling of the crossbars 5 with columns 1, 2, 3 and the columns themselves in height, the base size “a” of the cross section of 6 columns is kept constant (Figs. 5, 6, 7), and the number of reinforcing bars 7 is on the edge of the column , to which the crossbar 5 adjoins, is assumed to be equal to two within the basic size "a". The use of columns with different cross-sectional shapes allows, while increasing the load on the building and on the columns, to keep the minimum thickness of the external wall constant along the height of the building and at the same time hide the columns in the thickness of the external wall, which leads to an increase in the aesthetic attractiveness of the premises, especially in residential buildings .

To fill the gap formed under the lower plane of the floor section of the columns after monolithic elements of the frame, it is necessary to perform a curved channel 8 (Fig.8 and 9), which should go to the lateral plane from the lower horizontal plane of the floor section of the columns.

The pair of columns of different cross-sectional shapes 1 + 3 and 2 + 3 (Figs. 3 and 4) along the height of the building is made within the core of the cross-section of 6 columns 1, 2, 3, where the number of reinforcing bars 7 is taken to be four. The joint of the columns in height is made in the form of a plug connection in the middle zone of the floor section of the columns, where the values of bending moments are close to zero. Moreover, in the lower end part of the upper columns 1, 2, 3 within the core of section 6, regardless of the cross-sectional shape, there are releases of reinforcement 9, which, when lowering the columns 1, 2, 3, enter the grooves 10 located on the upper end part of the lower columns. In columns of a rectangular 1 and angular 2 cross-sectional shape, where there is a reinforcement 7 located outside the core of section 6, the releases of this reinforcement 11 are performed on the upper end part of the lower columns 1 and 2, which, when lowering the columns 1 and 2, should enter the grooves 12 located in the lower end part of the upper columns 1 and 2 (figure 10 ÷ 15). If a column of square section 3 is supported on the lower columns of a rectangular 1 or angular 2 cross-sectional shape, then it is lowered by its outlets of reinforcement 9 into the grooves 10 of the lower column, and the outlets of reinforcement 11 located outside the core of section 6 of the lower columns 1 or 2 are cut off.

To create more rigid knots for pairing the frame elements for the installation period, the crossbar 5 on the upper face of the support part has rectangular grooves 13 for laying the mounting support reinforcement 14, which at the first stage is monolithic at the same time with the crossbar 5 and columns 1, 2, 3 within the height of the assembly crossbar 5. In addition to the main decision on the device on the upper edge of the crossbar 5 loop-shaped releases of transverse reinforcement 15, which, due to the complexity of the installation, have different height of the releases, which leads to a mismatch of the design location of the support reinforcement 16 and, accordingly, to a possible decrease in the bearing capacity of a precast-monolithic crossbar, a second solution is proposed, the essence of which is as follows. The loopback outlets of the transverse reinforcement 17 in the supporting part of the prefabricated crossbar 5 must be arranged along the length of the crossbar 5 in two rows, which, after laying round hollow core slabs 18, the end surfaces 19 of which are inclined to the plane of the plate along its entire height with an inclination angle of 14 ÷ 16 °, and supporting reinforcement 16 are combined with loop clamps 20 located along the width of the precast bolt 5.

The proposed precast-monolithic reinforced concrete frame under the name "KAZAN-XXIv" made it possible to improve the reliability of the frame and the building as a whole, as well as by changing the cross-sectional shape of the columns, to improve the bearing structure due to the improvement of the interface elements of the frame elements and with minor changes in the formwork and reinforcement the ability to increase the number of storeys of the building and, by increasing the prefabricated structure, reduce to 7% the proportion of monolithic concrete per unit area of the floor, which plays an important role in the construction of the frame in the conditions of a long winter, characteristic of central Russia.

The technical solutions proposed in this invention are justified by the studies carried out, including using software computing systems, and are confirmed by calculations performed within the framework of the current design standards. Also, a number of technical solutions, in particular columns with different cross-sectional shapes, were used in the construction of a 10-story residential building on Tolbuhina St., Kazan.

Claims (4)

1. Prefabricated monolithic reinforced concrete frame of a multi-storey building, including precast reinforced concrete columns with holes in the level of the floors, prefabricated prestressed crossbars having horizontal recesses on the end faces, and hollow core slabs with a gap between their ends, which together with the holes in the columns monolithic at the same time with the released reinforcing releases from them of prefabricated frame elements, characterized in that the reinforced concrete columns, executed on several floors, have t different cross-sectional shapes - square, rectangular and angular, with the basic size of the core of the cross-section preserved and the number of reinforcing bars within the base core being fixed, the crossbars on the upper face of the supporting part have rectangular grooves for laying the mounting supporting reinforcement, and the end surfaces of the round-hollow floor slabs are made inclined to the plane of the plate along its entire height with an inclination angle of 14-16 °. 2. The frame according to claim 1, characterized in that the joint of the columns in height is made in the form of a plug connection in the middle zone of the floor section of the columns, while the ends of the columns have outlets of fittings and grooves where these outlets of fittings enter, but to maintain the uniformity of the joint of the columns of various cross-sectional shapes within the base core size, the reinforcement and grooves are made at the lower and upper ends of the column, respectively, and vice versa outside the base core, i.e. releases of fittings and grooves are made, respectively, at the upper and lower ends of the joined columns. 3. The frame according to claim 1, characterized in that in the prefabricated crossbars, the loop outlets of the transverse reinforcement in the support part of the crossbar are located along the length of the crossbar in two rows and are connected by loop clamps located along the width of the crossbar. 4. The frame according to claim 1 or 2, characterized in that to fill the gap formed under the lower plane of the floor section of the columns after monolithic elements of the frame, in the lower part of each floor section of the columns a curved channel is made connecting the lower horizontal plane of the floor section of the column with side plane.

Images