Disclosure of Invention
In view of the above analysis, the present invention aims to provide a plate-type cantilever structure and a production method, and solves the problems in the prior art that the cantilever beam occupies a part of the use space, the influence on the clear height of the building is large, the appearance of the exposed cantilever beam can be visually observed, the construction difficulty is increased and the material is wasted due to the fact that the cantilever beam is hidden by making a double-layer plate.
The purpose of the invention is mainly realized by the following technical scheme:
the invention provides a plate-type cantilever structure which comprises a plurality of single-pin cantilever units connected in sequence, wherein each single-pin cantilever unit comprises a frame post, an upper floor slab, a lower floor slab, a peripheral retaining wall and a frame beam arranged between two adjacent frame posts, the upper floor slab and the lower floor slab are arranged in the vertical direction and erected on a mounting surface through the frame posts and the frame beams, the peripheral retaining wall is arranged between the upper floor slab and the lower floor slab, the top end of the peripheral retaining wall is fixedly connected with the end part of the upper floor slab, and the bottom end of the peripheral retaining wall is fixedly connected with the end part of the lower floor slab; the upper floor, the peripheral retaining wall and the lower floor form an integral structure with a C-shaped cross section.
Furthermore, the contact surfaces of the upper floor slab and the lower floor slab with the frame column are both in a sawtooth shape; the zigzag single-tooth shape comprises an inclined edge, a first arc-shaped edge, a vertical edge and a second arc-shaped edge which are connected in sequence.
Furthermore, the cantilever length of the plate-type cantilever structure is less than 3.0m; the thickness of the upper floor and the lower floor is not less than 150mm.
Furthermore, the upper floor slab, the lower floor slab and the peripheral retaining wall are all made of reinforced concrete.
Furthermore, the upper floor slab, the lower floor slab, the peripheral retaining wall and the frame beam form a structure with a rectangular cross section, and a structural haunch is arranged at the corner.
Furthermore, the upper floor slab, the lower floor slab and the peripheral retaining wall are prefabricated members.
Further, the frame columns and the frame beams are cast-in-place pieces.
The invention also provides a production method of the plate-type cantilever structure, which is used for producing the plate-type cantilever structure and comprises the following steps:
step 1: and respectively prefabricating an upper floor slab, a lower floor slab and a peripheral retaining wall.
And 2, step: and (4) conveying the upper floor slab, the lower floor slab and the peripheral retaining wall to a construction site.
And 3, step 3: and binding reinforcing steel bars of the frame beam and the frame column on a construction site, installing a template of the frame beam and the frame column, pouring concrete slurry into the template, reserving part of the reinforcing steel bars at the top for connecting with an upper floor slab and a lower floor slab, and forming the frame column and the frame beam after curing.
And 4, step 4: and connecting the frame column, the frame beam, the upper floor slab, the lower floor slab and the peripheral retaining wall to complete the production of the plate type cantilever structure.
Furthermore, the mould that prefabricated upper floor and lower floor adopted includes a grout section of thick bamboo, end plate and folding circle, and the folding circle is conformal with the zigzag on upper floor and lower floor surface, and a grout section of thick bamboo is close to peripheral revetment one end opening, and the opening of a grout section of thick bamboo passes through the folding circle and is connected with the end plate for a grout section of thick bamboo, folding circle and end plate constitute sealed prefabricated molding chamber.
Further, the mould still includes protruding, the protruding and a plurality of butt joint poles of length difference of first butt, second butt, and protruding and end plate fixed connection of first butt, the protruding and grout section of thick bamboo fixed connection of second butt, the protruding butt of one end and the first butt of butt joint pole, the protruding butt of the other end and the second butt of butt joint pole.
Compared with the prior art, the invention can realize at least one of the following beneficial effects.
A) According to the plate type cantilever structure, the upper floor slab and the lower floor slab are connected through the peripheral retaining wall, so that the upper floor slab, the lower floor slab and the peripheral retaining wall form a whole body stressed together, the stress of the plate type cantilever structure is improved, and the deformation of the plate type cantilever structure is reduced.
B) According to the plate type cantilever structure provided by the invention, the peripheral retaining wall is arranged at the end parts of the upper floor slab and the lower floor slab, so that a structural system which has the advantages of no occupation of building clear height, simplicity and convenience in construction, material saving and capability of realizing a cantilever effect can be realized.
C) The plate type cantilever structure provided by the invention is mainly applied to newly built and reconstructed reinforced concrete structure projects which are provided with bare concrete peripheral retaining walls and have small cantilever length.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
Detailed Description
The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention.
The invention provides a plate type overhanging structure, which comprises a plurality of single overhanging units connected in sequence, wherein each single overhanging unit comprises a frame column 1, an upper floor 2, a lower floor 3, a peripheral retaining wall 4 and a frame beam 5 arranged between two adjacent frame columns 1, the upper floor 2 and the lower floor 3 are arranged in the vertical direction and erected on a mounting surface through the frame columns 1 and the frame beams 5, the peripheral retaining wall 4 is arranged between the upper floor 2 and the lower floor 3, the top end of the peripheral retaining wall 4 is fixedly connected with the end of the upper floor 2, the bottom end of the peripheral retaining wall 4 is fixedly connected with the end of the lower floor 3, and the upper floor 2, the peripheral retaining wall 4 and the lower floor 3 form an integral structure with a C-shaped cross section, as shown in the figures 1 to 3.
Compared with the prior art, the plate type cantilever structure provided by the invention has the advantages that the upper floor 2 and the lower floor 3 are connected through the peripheral retaining wall 4, so that the upper floor 2, the lower floor 3 and the peripheral retaining wall 4 form a common stressed whole, the stress of the plate type cantilever structure is improved, and the deformation of the plate type cantilever structure is reduced. In addition, the peripheral retaining wall 4 is arranged at the end parts of the upper floor slab 2 and the lower floor slab 3, so that a structural system which has the advantages of no building clear height, simplicity and convenience in construction, material saving and cantilever effect can be realized.
It should be noted that the plate-type cantilever structure is mainly applied to newly-built and reconstructed reinforced concrete structural engineering provided with the bare concrete peripheral retaining wall 4 and with a small cantilever length (generally not greater than 3 meters).
Illustratively, the thickness of the upper floor 2 and the lower floor 3 is not less than 150mm when the overhanging length is less than 3.0 m.
It should be noted that, because the buildings adopting the plate-type overhanging structures have the requirement of fair-faced concrete effect, the materials of the upper floor 2, the lower floor 3 and the peripheral retaining wall 4 are all reinforced concrete.
It is to be noted that, in the above-described panel cantilever structure, the upper floor 2, the lower floor 3, the peripheral retaining wall 4, and the frame beam 5 are exemplarily configured to have a rectangular cross-sectional shape, and bending moments are large at four corners of the above-described structure, and in order to improve the structural rigidity of the whole structure, the structural haunches 6 are provided at the corners. Like this, through the setting of structure haunches 6, can effectively reduce the arrangement of reinforcement area and the overall rigidity that improves board-like structure of encorbelmenting of these corners, simultaneously, can not produce great influence to the architectural effect.
In order to effectively improve the construction efficiency, the upper floor 2, the lower floor 3 and the peripheral retaining wall 4 can be prefabricated parts, and the frame columns 1 and the frame beams 5 are cast-in-place parts.
Considering different construction modes, certain difference inevitably exists between contact surfaces of the upper floor 2 and the lower floor 3, and the peripheral retaining wall 4, in order to improve the contact stability between the upper floor 2 and the peripheral retaining wall 4 and the lower floor 3, the surfaces (i.e. the lower surfaces) of the upper floor 2 and the lower floor 3, which are in contact with the peripheral retaining wall 4, are both in a zigzag shape, and correspondingly, the top end and the bottom end of the peripheral retaining wall 4 are also in a zigzag shape, so that the roughness between the contact surfaces of the upper floor 2 and the peripheral retaining wall 4 and the roughness between the contact surfaces of the lower floor 3 and the peripheral retaining wall 4 are increased, and the zigzag contact surfaces can effectively improve the connection strength between the upper floor 2 and the peripheral retaining wall 4 and the connection strength between the lower floor 3 and the peripheral retaining wall 4.
For the zigzag single tooth shape, the tooth-shaped single tooth comprises an inclined edge 201, a first arc-shaped edge 202, a vertical edge 203 and a second arc-shaped edge 204 which are connected in sequence. This is because, due to the provision of the zigzag portions, there may occur a problem that concrete grout cannot be poured into the zigzag corners during the production of the upper floor 2 and the lower floor 3 and the grouting of the upper floor 2 and the lower floor 3, and by designing the shape of the single tooth, the concrete grout can flow into the zigzag corners along the inclined edge 201 and the first arc-shaped edge 202, and then flow into the next single tooth along the vertical edge 203 and the second arc-shaped edge 204.
The invention also provides a production method of the plate type cantilever structure, which comprises the following steps:
step 1: the upper floor slab, the lower floor slab and the peripheral retaining wall are produced by the vertical mold, the upper floor slab, the lower floor slab and the peripheral retaining wall are produced vertically along the width direction, the occupied space is small, different quantities can be combined randomly, a plurality of prefabricated upper floor slabs, lower floor slabs and peripheral retaining walls are produced at one time, and the production efficiency is improved;
step 2: conveying the upper floor slab, the lower floor slab and the peripheral retaining wall to a construction site;
and step 3: binding reinforcing steel bars of a frame beam and a frame column on a construction site, installing a template of the frame beam and the frame column, pouring concrete slurry into the template, reserving part of the reinforcing steel bars at the top for connecting with an upper floor slab and a lower floor slab, and forming the frame column and the frame beam after curing;
and 4, step 4: and connecting the frame column, the frame beam, the upper floor slab, the lower floor slab and the peripheral retaining wall to complete the production of the plate type cantilever structure.
Compared with the prior art, the beneficial effects of the production method of the plate-type cantilever structure provided by the invention are basically the same as those of the plate-type cantilever structure provided by the invention, and are not repeated herein.
In practical application, considering that the lengths of the upper floor and the lower floor are different for different-scale buildings, in order to enable the mold to adapt to a certain range of lengths of the upper floor and the lower floor, for the structure of the mold for prefabricating the upper floor and the lower floor, see fig. 4 to 5, specifically, the mold comprises a grouting cylinder 7, an end plate 8 and a folding ring 9, it is noted that the folding ring 9 is conformal with the zigzag shape of the upper floor and the lower floor, the required zigzag shape can be formed through the folding ring 9, one end of the grouting cylinder 7 close to the peripheral retaining wall is opened, the opening of the grouting cylinder 7 is connected with the end plate 8 through the folding ring 9, so that the grouting cylinder 7, the folding ring 9 and the end plate 8 form a sealed prefabricated forming cavity, and thus, the length of the prefabricated upper floor and the length of the lower floor can be adjusted by adjusting the width of the folding ring 9 because the width of the folding ring 9 is adjustable.
In order to avoid the width of the folding ring to change when concrete placement, influence the shaping precision of prefabricated upper floor and lower floor length, above-mentioned mould still includes first butt arch 10, the protruding 11 and the different a plurality of butt link 12 of length of second butt, the protruding 10 and end plate 8 fixed connection of first butt, the protruding 11 and grout section of thick bamboo 7 fixed connection of second butt, the protruding 10 butt of one end and first butt of butt link 12, the other end and the protruding 11 butt of second butt of butt link 12, through the butt link 12 of changing different length, make folding ring 9 can fix and be unchangeable at a width.
Example one
In this embodiment, referring to fig. 6, the peripheral retaining wall is provided with a horizontal slit, the weight of the peripheral retaining wall is applied as a load to the upper floor and the lower floor, and the upper floor and the lower floor are separately stressed.
Example two
In this embodiment, referring to fig. 7, the peripheral retaining wall is not provided with a horizontal seam, the peripheral retaining wall is of a continuous structure, and the peripheral retaining wall, the upper floor slab and the lower floor slab are integrally stressed.
At the same component cross section (the height of the peripheral retaining wall is 4600mm, the thickness is 200 mm) and the same load action (the live load of the upper floor slab is 0.5 KN/m) 2 Constant load of 6KN/m 2 Live load of lower floor slab 3.5KN/m 2 Constant load of 5KN/m 2 ) The displacement and internal force conditions of the structures of example one and example two were compared, respectively, and as can be seen from comparison of the calculation results in fig. 8 to 9: the structure of the second embodiment (namely, the peripheral retaining wall, the upper floor slab and the lower floor slab are integrally stressed) can greatly reduce the vertical displacement of the structure from 50mm to 15mm, and the vertical rigidity of the structure is obtainedThe requirement of the specification on flexibility and comfort is met more easily; the bending moment of the upper floor and the lower floor at the support is greatly reduced from 91.1 KN.m to 52.6 KN.m, the reduction amplitude is 42%, and the possibility of reducing the thickness of the floor and reinforcing bars of the floor is provided.
EXAMPLE III
By comparing the cross section of the same component (the height of the peripheral retaining wall is 4600mm, the thickness is 200mm, the thickness of the upper floor and the lower floor are 120 mm), the same load action (the live load of the upper floor is 0.5 KN/m) 2 Constant load of 6KN/m 2 Live load of lower floor slab is 3.5KN/m 2 Constant load of 5KN/m 2 ) The reasonable overhanging length of the concrete slab structure was quantitatively determined by the displacement and internal force of the structure with different overhanging length, specifically, the overhanging length was set to 3.8m, 3.04m, 2.28m and 1.52m, respectively.
TABLE 1 comparison of internal force and displacement of overhanging structures of different overhanging lengths
Note: the deflection is shown in proportion in brackets and the specification provides a limit of 1/250.
From the table 1, it can be known that, with the decrease of the cantilever length, the internal forces such AS the member bending moment, the shearing force, the axial force and the like and the end displacement are all decreased, and according to the simplified calculation formula AS = M/(0.9x360xh0) of the reinforcement of the flexural member, the reinforcement areas of the stressed reinforcements of the upper floor and the lower floor are shown in table 2.
TABLE 2 reinforcing steel bar reinforcing bar of cantilever structure with different cantilever lengths
From the economic and rationality angle of floor slab reinforcement ratio, generally control is not more than 1.0%, for the condition that the thickness of upper floor slab and lower floor slab is 120mm, the overhanging length is more than 3.0m, the floor slab reinforcement ratio is obviously bigger than normal, the floor slab thickness must be increased to reduce the reinforcement.
Example four
The influence condition of the change of the thickness of the floor slab on the stress of the structure is qualitatively judged by comparing the displacement and the internal force of the structure under the same load action, the same cantilever length and different floor slab thicknesses. Based on the model with the overhanging length of 3.04m, the thicknesses of the upper floor slab and the lower floor slab are the same, and the four thicknesses of 120mm, 150mm, 180mm and 210mm are compared respectively, and the calculation result is shown in the following table 3:
TABLE 3 comparison of internal force and displacement of plate-type overhanging structure with different floor thicknesses
By comparison, it can be seen that: along with the increase of the thickness of the floor slab, the weight of the structure is increased, the bending moment at the floor slab support is correspondingly increased, but the increase range is not large, but the displacement of the end part of the structure is obviously reduced, the plate thickness is increased to 150mm from 120mm, the thickness is increased by 25%, the displacement of the end part is reduced by 41%, and the bending moment at the floor slab support is only increased by 7.9%. Therefore, the thickness of the upper floor and the lower floor is properly increased, which is beneficial to increasing the vertical rigidity of the structure and reducing the reinforcement ratio of the floor.
Therefore, according to the third embodiment and the fourth embodiment, the comprehensive consideration is given to structural displacement, floor slab reinforcement ratio and the like, the cantilever length of the plate type cantilever structure is directly related to the thicknesses of the upper floor slab and the lower floor slab, the larger the thickness of the floor slab is, the larger the cantilever capacity of the structure is, and the larger the thickness of the floor slab can realize large cantilever. When the overhanging length is less than 3.0m, the thickness of the upper floor slab and the lower floor slab is recommended to be not less than 150mm; when the overhanging length is more than 3.0m, the thickness of the floor slab should be thickened correspondingly.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.