SU737580A1 - Prefabricated ferroconcrete framework of multistorey building - Google Patents

Description

(54) REINFORCED CONCRETE FRAME MULTILEVEL BUILDING

The invention relates to the construction, in particular to the structures of precast reinforced concrete spatial frames of high-rise buildings with flat floors.

The precast reinforced concrete frame of a multistory building with ribbed slabs and columns located in the nodes of the center grid of axes with rectangular cells is known, in which the ribs of the overhead column slabs serve as crossbars of the transverse and longitudinal frames of the corks, and the ribs of the additional slabs are secondary beams. transferring the load on the girder frames 1.

The main disadvantage of such a frame is the inefficient arrangement of the ribs, which do not ensure the transfer of vertical loads on the columns along the shortest path: each secondary beam collecting the load from a certain section of the ceiling transmits it in response to frames and then to columns, due to which, the same load consistently causes internal forces in the said overlapping elements. The result of this is a large total area of plots of internal forces of all the ribs and, as a result, increased material consumption. The arrangement of the ribs does not ensure their effectiveness as well: neither in the work of the carcass on horizontal loads; when the latter act, only the ribs serving as frame bolts are included in the work.

The disadvantages of this framework also include the floor cutting of columns, the weakening of the cross section and the complication of the shape O of the plates due to the formation of shelves in them, as well as the presence of cantilever protrusions of the subcolumns of the extreme rows of columns, which makes it difficult for a variety of space planning.

The closest to the invention is 15 with a precast reinforced concrete frame of the building and structures with overlaps of precast slabs supported on columns located in nodes p; the bead net of axes with triangular cells. The plates adjoin each other 20 along the bisectors of the angles of the triangular cells 2.

Claims (2)

Due to the absence of crossbars in the specified frame, the advantages of the triangular grid of axes are not used to increase its spatial rigidity under the action of horizontal loads, and the nature of the work of a flat monolithic plate on vertical loads does not meet the principle of transferring this column load along the shortest path, which leads to an increased material intensity of the frame. In addition, the disadvantages of this framework are floor cutting of columns, a large number of precast elements of the ceiling, the presence of shelves in the local interface of plates, as well as cantilever projections of columnar plates at the extreme rows of columns. The purpose of the invention is to reduce the effort in the overlap elements, increase the spatial rigidity of the frame, reduce the number of mounting elements and reduce material consumption. This is achieved by the fact that in the precast concrete frame of a multi-storey building, including columns, installed in the nodes of the center grid axes with triangular cells, and ribbed slabs supported on the columns, the latter are made with edges located along the sides and the bisectors of the corners of the triangular cells. In order to unify the shuttering forms of slabs and their joints to the columns, the latter, located at the intersection of the intermediate axes, have cantilevers in the plane of the slab in the shape of a regular hexagon, and the columns, located on the outer axes, are in the shape of a polygon, including sides perpendicular to the axis of the center grid. In addition, in order to eliminate torsion in the edges of the plates located along the bisectors of the angles of the center triangles: grids of the axes, the plates can be made with an additional edge located along the bisector of the corners of the plate. The torsion of these edges can also be eliminated without making additional edges by connecting metal parts of the corners of the plates located at the intersection of the bisectors of the angles of the triangles of the center grid. The location of the plate edges ensures the direct loading of the vertical load on each of them onto the columns without first transferring this load in the form of a concentrated reaction to the other edges; which leads to a decrease and a relative equation of force in the ribs. When a horizontal load is applied to the skeleton, all the edges of the plates converging to the column are included as straight, L-shaped or Y-shaped in terms of crossbars of the frame, which increases its spatial rigidity. The accepted cutting of the ceiling into prefabricated elements makes it possible to use the column frame with a multistory cutting during installation and to reduce the number of mounting elements of the ceiling. The location of the ribs along the seams of the interface of the plates eliminates the appearance of forces in the seams, normal to the side surfaces of the plates, and the absence in the overlap of continuous seams located on the same straight line provides greater rigidity of the curve in its plane. This eliminates embedment of the seams with the formation of dowels along their entire length, replacing this process with simple sealing of the seams, as a result of which the shape of the side surfaces of the plates is simplified and the labor intensity is reduced. FIG. I depicts the proposed frame, plan; in fig. 2 - site adjoining slabs to the column; in fig. 3 shows section A-A in FIG. 2; in fig. 4 and 5 are possible layouts for the construction of overlaps of precast slabs. The precast reinforced concrete frame includes a column 1 with a multistory cutting, located in the nodes of the center grid of axes with triangular cells and made with cantilevers 2 or 3, having metal supporting tables with horizontal element 4 and vertical stiffener 5 at the intersection of their sides, on which they rest intermediate 6 and extreme 7 and (or) 8 overlapping plates, mating with each other along the bisectors of the angles of the triangles of the center grid of the axes. In this case, the vertical stiffening ribs 5 of the metal support tables, designed for sensing the transverse force in the knot, are located in the seams between the plates. Intermediate 6 and extreme 7 and 8 slabs are made with edges 9 and 10 located along the sides and bisectors of the corners of the triangles of the center grid, and with an additional edge 11 (or without it) located along the bisector of the obtuse corner of the plate. The ratio of the width of the rib 9 to the width of the rib 10 is determined by the condition of equality of their deflections when the slab is loaded with a full design load. In case of a possible large size of one-sided vertical load on the plates, they can be connected in a node located at the intersection of the bisectors of the triangles of the center grid, connections 12, which perceive the mutual displacement of the plates vertically, and in the absence of additional edges in the plates 11 - links 13, which prevent the torsion of the ribs 10. Additional plates 14 are used to create rectangular overlaps in the plan. Extreme plates 8 can have various shapes depending on the specific space-planning Nogo solutions of buildings. In this case, plates 7, 8 and 14 can be made in the same formwork form as slab b, with the installation in the form of appropriate liners. Floor slabs can be made with closed voids or protruding ribs. When mounting the described frame after the installation of the floor slabs on the metal support tables, a rigid joint of the slabs to the column brackets is created by any known constructive method. Claim 1. Prefabricated reinforced concrete frame of a multi-storey building, including columns, installed in the nodes of the center grid of axes with triangular cells, and ribbed slab floor plates supported on the columns, characterized in that, in order to reduce the material intensity of the frame, reduce the efforts in the ceiling, increase spatial stiffness the frame, the slab is made with ribs located along the sides and bisectors of the angles of triangular cells, 2. The carc under item 1, characterized in that the columns installed at the intersection points and intermediate axes are in the plane of overlap of the console in the form of a regular schestiugolbnika and KolonNBg situated outer axes - in the form of a polygon comprising a side perpendicular to the axis of the stake mesh. 3. The framework according to claim 1, wherein each slab is provided with an additional rib located along the bisector of the obtuse corner of the slab. Sources of information taken into account during the examination 1. USSR author's certificate No. 553335, cl. E 04 B 1/02, 1974. 2. USSR author's certificate number 544734, cl. E 04 B 1/18, 1975. ten S- 2. Chfig .2. Aa 7 2