Unidirectional prestress fabricated frame with non-tensile composite floor slabs and construction method

Abstract

The invention provides a one-way prestress assembly type frame with a non-tensile composite floor slab and a construction method. A steel reinforced concrete composite beam, a prefabricated concrete composite beam and the non-tensile composite floor slab are each formed by overlapping a section steel beam, a prefabricated beam and a prefabricated bottom plate with post-pouring concrete; an in-column reserved hole channel is formed in the prefabricated concrete column, an in-beam reserved hole channel is formed in the prefabricated beam, and the prestressed tendons penetrate through the in-column reserved hole channels and the in-beam reserved hole channels correspondingly and are connected in a pressed mode by tensioning the prestressed tendons. The profile steel beam is connected with the prefabricated concrete column through a steel corbel, studs are symmetrically welded to the upper portion of the profile steel beam along the center line, and the side faces of the studs are wrapped with low-elastic-modulus materials; the four edges of the prefabricated bottom plate are placed on the section steel beams and the prefabricated beams correspondingly, and low-elastic-modulus materials are embedded into the peripheries of the prefabricated concrete columns and the middle lines of the upper portions of the section steel beams, so that the post-pouring concrete laminated layer is separated from the prefabricated concrete columns. The problem that under the earthquake action, a prestress assembly type frame floor slab is cracked due to opening of a beam column interface is solved.

Description

Technical Field

[0001] The invention belongs to a concrete frame and its construction method, and particularly relates to a one-way prestressed assembled frame with a non-tensile composite floor slab and a construction method thereof. Background Art

[0002] The cast-in-place concrete frame has good overall performance, but formwork support is required during the construction process, which increases the time and construction cost, and it is severely damaged under strong earthquake action, and the repair and reconstruction costs are relatively high; although the assembled frame reduces the use of formwork, the complex structure at the joints still increases the construction difficulty. The prestressed assembled frame presses and connects the precast beam and the precast column through prestressing tendons. During the earthquake, the frame beam and column basically remain elastic, greatly reducing the seismic damage of the structure.

[0003] The floor slab of the prestressed assembled frame is usually designed as a composite slab, which consists of a precast bottom slab and a cast-in-place concrete composite layer. The precast bottom slab is precast in the factory and then transported to the construction site for assembly, which can be used as the formwork for pouring the cast-in-place concrete composite layer, shortening the building construction period and improving the economy of the structure.

[0004] However, due to the unique press-connection structure form of the prestressed assembled frame, when an earthquake occurs, the beam-column interface of the prestressed assembled frame will open, which will cause the floor slab in the joint area to be subjected to tensile force and crack, seriously affecting the safety performance of the structure.

[0005] Therefore, it is necessary to specifically develop a new type of concrete frame and its construction method to avoid the problem that the floor slab of the prestressed assembled frame is pulled and cracked due to the opening of the beam-column interface under earthquake action. Summary of the Invention

[0006] Object of the Invention: Aiming at the deficiencies and defects of the prior art, the invention provides a one-way prestressed assembled frame with a non-tensile composite floor slab and a construction method thereof. By embedding a low elastic modulus material around the precast concrete column and at the midline position of the upper part of the steel beam, the cast-in-place concrete composite layer can be separated from the precast concrete column, and at the same time, it can be separated at the midline position of the upper part of the steel beam, so as to solve the problem that the floor slab of the prestressed assembled frame is pulled and cracked due to the opening of the beam-column interface under earthquake action.

[0007] Technical solution: A one-way prestressed prefabricated frame with a non-tensile composite floor slab according to the present invention is characterized in that it comprises precast concrete columns, steel-concrete composite beams, precast concrete composite beams, non-tensile composite floor slabs and prestressing tendons; the steel-concrete composite beams, precast concrete composite beams and non-tensile composite floor slabs are respectively composed of steel beams, precast beams and precast floor slabs which are respectively superposed with post-cast concrete; column inner reserved ducts are provided in the precast concrete columns, beam inner reserved ducts are provided in the precast beams, and the prestressing tendons respectively pass through a number of column inner reserved ducts and beam inner reserved ducts and are pressed by tensioning the prestressing tendons; the steel beams are connected to the precast concrete columns through steel corbels, studs are symmetrically welded along the midline on the upper part of the steel beams, and the sides of the studs are wrapped with low elastic modulus materials; the four sides of the precast floor slab are respectively placed on the steel beams and precast beams, and low elastic modulus materials are embedded at the midline positions around the precast concrete columns and on the upper part of the steel beams, so that the post-cast concrete composite layer is separated from the precast concrete columns and is also separated at the midline position on the upper part of the steel beams.

[0008] Wherein, a steel corbel is reserved on the side of the precast concrete column and is connected to the steel beam by welding or bolt connection.

[0009] Wherein, the diameter of the head of the stud is not less than the sum of the diameter of the stud bar and twice the thickness of the low elastic modulus material.

[0010] Wherein, the low elastic modulus material is rubber or foam plastic.

[0011] Wherein, the steel beam is an H-shaped steel beam or an H-shaped steel beam with concrete wrapped outside or partially wrapped outside.

[0012] Wherein, the laying length of the precast floor slab on the steel beam is not less than the product of the maximum inter-story drift angle of the floor and the beam height of the precast concrete composite beam.

[0013] Wherein, the steel bars of the precast floor slab and the steel bars of the post-cast concrete composite layer are on the upper part of the steel beam, extend into the post-cast concrete composite layer of the steel-concrete composite beam but do not exceed the midline of the steel beam.

[0014] The construction method of the one-way prestressed prefabricated frame with a non-tensile composite floor slab according to the present invention is characterized in that it comprises the following steps:

[0015] 1) Precast concrete columns, steel beams welded with studs, precast beams and precast floor slabs are produced in the factory;

[0016] 2) Position the precast concrete columns, steel beams and precast beams at the construction site, connect the steel corbels and the steel beams by welding or bolt connection to connect the precast concrete columns and the steel beams; the precast concrete columns and the precast beams are pressed by tensioning the prestressing tendons;

[0017] 3) Place the four sides of the precast floor slab on the profiled steel beams and precast beams, and embed low elastic modulus materials at the sides of the stud bolts, around the precast concrete columns and at the midline position of the upper part of the profiled steel beams;

[0018] 4) Pour concrete to form the post-cast concrete composite layer of the profiled steel concrete composite beam, precast concrete composite beam and non-tensile composite floor slab, and the concrete layer wrapped outside the steel corbel.

[0019] Working principle: The prestressed precast frame presses and connects the precast beam and precast column through prestressed tendons. During the earthquake, the frame beams and columns basically remain elastic, greatly reducing the seismic damage of the structure; the precast floor slab in the prestressed precast frame can be used as the formwork for pouring the post-cast concrete composite layer, eliminating the need for additional formwork, shortening the building construction period and improving the construction efficiency; low elastic modulus materials are embedded around the precast concrete columns and at the midline position of the upper part of the profiled steel beams, enabling the post-cast concrete composite layer of the floor slab to be separated from the precast concrete columns during the earthquake, and at the same time, adjacent one-way floor slabs can be separated at the midline position of the upper part of the profiled steel beams, effectively solving the problem that the post-cast concrete composite layer of the prestressed precast frame floor slab is cracked due to the opening of the beam-column interface.

[0020] Compared with the prior art, the present invention has the following remarkable advantages: The present invention solves the problem that the post-cast concrete composite layer of the prestressed precast frame floor slab is cracked due to the opening of the beam-column interface by cutting off the tensile connection between the one-way floor slab and the frame column and between adjacent one-way floor slabs. The present invention presses and connects the precast beam and precast column through prestressed tendons. During the earthquake, the frame beams and columns basically remain elastic, significantly improving the construction efficiency and effectively reducing the seismic damage of the structure. The present invention embeds low elastic modulus materials around the precast concrete columns and at the midline position of the upper part of the profiled steel beams, enabling the post-cast concrete composite layer of the floor slab to be separated from the precast concrete columns during the earthquake, and at the same time, adjacent one-way floor slabs can be separated at the midline position of the upper part of the profiled steel beams, effectively solving the problem that the floor slab is cracked due to the opening of the beam-column interface. The side of the precast concrete column of the present invention is reserved with a steel corbel, which is connected to the profiled steel beam by welding or bolt connection, improving the construction efficiency while ensuring the reliable connection between the beam and column. The stud bolts and the stirrups in the precast beam of the present invention extend into the post-cast concrete composite layer of the floor slab, effectively connecting the precast and composite parts of the concrete frame and significantly enhancing the overall performance of the structure. Brief Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of Embodiment 1 of the present invention;

[0022] Figure 2 It is a sectional view taken along line A-A of Embodiment 1 of the present invention;

[0023] Figure 3 It is a sectional view taken along line B-B of Embodiment 1 of the present invention;

[0024] Figure 4Node connection of Embodiment 1 of the present invention Figure 1 ;

[0025] Figure 5 Node connection of Embodiment 1 of the present invention Figure 2 ;

[0026] Figure 6 Cross-sectional view of plane A-A of Embodiment 2 of the present invention;

[0027] Figure 7 Cross-sectional view of plane A-A of Embodiment 3 of the present invention;

[0028] Figure 8 Node connection of Embodiment 4 of the present invention Figure 1 ;

[0029] Figure 9 Node connection of Embodiment 4 of the present invention Figure 2 ;

[0030] Figure 10 Node connection of Embodiment 5 of the present invention Figure 1 ;

[0031] Figure 11 Node connection of Embodiment 5 of the present invention Figure 2 ;

[0032] Figure 12 Bending moment schematic diagram of the A-A section of Embodiment 1 of the present invention under normal use conditions;

[0033] Figure 13 Deformation schematic diagram of the elevation of Embodiment 1 of the present invention under seismic load;

[0034] Figure 14 Deformation schematic diagram of the A-A section of Embodiment 1 of the present invention under seismic load.

[0035] In the figure, 1 is a precast concrete column; 11 is a reserved hole in the column; 12 is a steel corbel; 2 is a profiled steel concrete composite beam; 21 is a profiled steel beam; 211 is a stud; 2111 is the nail head; 2112 is the stud bar; 212 is a low elastic modulus material; 3 is a precast concrete composite beam; 31 is a precast beam; 311 is a reserved hole in the beam; 4 is a non-tensile composite floor slab; 41 is a precast bottom slab; 5 is a prestressed tendon. Detailed implementation manners

[0036] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific implementation manners.

[0037] Embodiment 1:

[0038] As Figure 1 , Figure 2 ,Figure 3 , Figure 4 and Figure 5 , the one-way prestressed precast frame with non-tensile composite floor slab in this embodiment includes a precast concrete column 1, a steel reinforced concrete composite beam 2, a precast concrete composite beam 3, a non-tensile composite floor slab 4 and prestressing tendons 5. The steel reinforced concrete composite beam 2, the precast concrete composite beam 3 and the non-tensile composite floor slab 4 are respectively composed of a steel beam 21, a precast beam 31 and a precast bottom slab 41 by being respectively superimposed with post-cast concrete. Column inner reserved ducts 11 and beam inner reserved ducts 311 are respectively arranged in the precast concrete column 1 and the precast beam 31. The prestressing tendons 5 respectively pass through a plurality of column inner reserved ducts 11 and beam inner reserved ducts 311. The precast concrete column 1 and the precast beam 31 are compression-connected by tensioning the prestressing tendons 5. A steel corbel 12 is arranged on the side of the precast concrete column 1. The precast concrete column 1 and the steel beam 21 are welded and connected through the steel corbel 12. Studs 211 are symmetrically welded along the upper middle line of the steel beam 21. The sides of the studs 211 are wrapped with low elastic modulus materials 212. The nail caps 2111, the stud bars 2112 of the studs 211 and the low elastic modulus materials 212 are all arranged in the post-cast concrete layer of the steel reinforced concrete composite beam 2. The four sides of the precast bottom slab 41 are respectively placed on the steel beam 21 and the precast beam 31. The placement length of the precast bottom slab 41 on the steel beam 21 is not less than the product of the maximum inter-story drift angle of the floor and the beam height of the precast concrete composite beam 3. Low elastic modulus materials 212 are embedded around the precast concrete column 1 to separate the post-cast concrete composite layer from the precast concrete column 1. Low elastic modulus materials 212 are also embedded at the upper middle line position of the steel beam 21 to ensure the separation of the post-cast concrete composite layer of the non-tensile composite floor slab 4 at the upper middle line position of the steel beam 21. The steel bars of the precast bottom slab 41 on the upper part of the steel beam 21 extend into the post-cast concrete composite layer of the steel reinforced concrete composite beam 2, and the steel bars in the post-cast concrete composite layer shall not exceed the middle line of the steel beam 21.

[0039] The construction method of this embodiment includes the following steps:

[0040] 1) Factory production of precast concrete columns 1, steel beams 21 welded with studs 211, precast beams 31 and precast bottom slabs 41;

[0041] 2) Position the precast concrete column 1, the steel beam 21 and the precast beam 31 at the construction site, and connect the precast concrete column 1 and the steel beam 21 by welding or bolting the steel corbel 12 to the steel beam 21; the precast concrete column 1 and the precast beam 31 are compression-connected by tensioning the prestressing tendons 5;

[0042] 3) Place the four sides of the precast bottom slab 41 on the steel beam 21 and the precast beam 31, and embed low elastic modulus materials 212 on the sides of the studs 211, around the precast concrete column 1 and at the upper middle line position of the steel beam 21;

[0043] 4) Pour concrete to form the post-cast concrete overlay of the steel reinforced concrete composite beam 2, the precast concrete composite beam 3 and the non-tensile composite floor slab 4, as well as the concrete layer wrapping the steel corbel 12.

[0044] Example 2:

[0045] As Figure 6 , the rest of the structure of this example is the same as that of Example 1. The difference is that the shape of the steel beam 21 is a concrete-wrapped H-shaped steel beam.

[0046] Example 3:

[0047] As Figure 7 , the rest of the structure of this example is the same as that of Example 1. The difference is that the shape of the steel beam 21 is a partially concrete-wrapped H-shaped steel beam.

[0048] Example 4:

[0049] As Figure 8 , Figure 9 , the rest of the structure of this example is the same as that of Example 1. The difference is that the steel corbel 12 reserved on the side of the precast concrete column 1 is connected to the steel beam 21 through bolt connection.

[0050] Example 5:

[0051] As Figure 10 , Figure 11 , the rest of the structure of this example is the same as that of Example 4. The difference is that the shape of the steel beam 21 is a concrete-wrapped H-shaped steel beam.

[0052] As Figure 12 , under the action of vertical load, the prestressed precast frame of Example 1 is allowed to have one-way sliding but not rotation of the non-tensile composite floor slab 4 because only the low elastic modulus material 212 is wrapped on the side of the stud 211. Therefore, the prestressed precast frame of this Example 1 has the flexural bearing capacity of "equivalent to cast-in-place" in the splicing area of the non-tensile composite floor slab 4.

[0053] As Figure 13 , under the action of seismic load, the prestressed precast frame of Example 1 undergoes lateral deformation, and the interface between the precast concrete column 1 and the precast beam 31 opens. The low elastic modulus material 212 filled around the precast concrete column 1 mainly has two functions: First, assist the separation of the precast concrete column 1 from the post-cast overlay; Second, avoid local crushing when the precast concrete column 1 is extruded by the post-cast overlay.

[0054] As Figure 14, in the prestressed precast frame of Embodiment 1, the non-tensile composite floor slab 4 undergoes one-way sliding under the action of seismic loads. The opening of the interface between the precast concrete column 1 and the precast beam 31 drives the non-tensile composite floor slab 4 on the upper left side of the steel beam 21 to be in tension, and the low elastic modulus material 212 on the side of the stud 211 in the post-cast concrete composite layer of the non-tensile composite floor slab 4 on the upper left side of the steel beam 21 slides to the left relative to its original position; conversely, the opening of the interface between the precast concrete column 1 and the precast beam 31 drives the non-tensile composite floor slab 4 on the upper right side of the steel beam 21 to be in compression, and the low elastic modulus material 212 on the side of the stud 211 in the post-cast concrete composite layer of the non-tensile composite floor slab 4 on the upper right side of the steel beam 21 slides to the right relative to its original position. Finally, by embedding the low elastic modulus material 212 at the midline position of the upper part of the steel beam 21, the adjacent one-way non-tensile composite floor slabs 4 can be separated at the midline position of the upper part of the steel beam 21 under seismic action.

[0055] Effect analysis:

[0056] In Embodiments 1-5, by crimping the precast beam and the precast column with prestressing tendons, the frame beam and column basically remain elastic during the earthquake, significantly improving the construction efficiency and effectively reducing the seismic damage of the structure. By embedding low elastic modulus materials around the precast concrete column and at the midline position of the upper part of the steel beam, the post-cast concrete composite layer of the floor slab can be separated from the precast concrete column under seismic action, and at the same time, adjacent one-way floor slabs can be separated at the midline position of the upper part of the steel beam, effectively solving the problem that the floor slab is cracked due to the opening of the beam-column interface. Steel corbels are reserved on the side of the precast concrete column and connected to the steel beam by welding or bolts, improving the construction efficiency while ensuring reliable connection between the beam and column. The studs and the stirrups in the precast beam extend into the post-cast concrete composite layer of the floor slab, effectively connecting the precast and composite parts of the concrete frame and significantly improving the overall performance of the structure.

Claims

1. A one-way prestressed assembled frame with a non-tensile composite floor, characterized in that: The invention comprises a precast concrete column (1), a steel-concrete composite beam (2), a precast concrete composite beam (3), a non-tensile composite floor slab (4) and a prestressed tendon (5); the steel-concrete composite beam (2), the precast concrete composite beam (3) and the non-tensile composite floor slab (4) are respectively composed of a steel beam (21), a precast beam (31) and a precast bottom plate (41) which are respectively laminated with post-cast concrete; the precast concrete column (1) is provided with a column reserved channel (11), the precast beam (31) is provided with a beam reserved channel (311), and the prestressed tendon (5) passes through a plurality of column reserved channels (11) and beam reserved channels (311) respectively. 1), by tensioning the prestressed tendons (5) for crimping; the steel beam (21) and the precast concrete column (1) are connected by a steel bracket (12), the upper part of the steel beam (21) is symmetrically welded with studs (211) along the center line, and the side of the studs (211) is wrapped with low elastic modulus material (212); the four sides of the precast base plate (41) are respectively placed on the steel beam (21) and the precast beam (31), and the low elastic modulus material (212) is embedded around the precast concrete column (1) and at the center line position of the upper part of the steel beam (21), so that the post-cast concrete superimposed layer is separated from the precast concrete column (1), and at the same time separated at the center line position of the upper part of the steel beam (21).

2. The one-way prestressed assembled frame with non-tensile composite floor slab according to claim 1, characterized in that: The side of the precast concrete column (1) is provided with a steel bracket (12) which is connected to the steel beam (21) by welding or bolt connection.

3. The one-way prestressed assembled frame with non-tensile composite floor slab according to claim 1, characterized in that: The diameter of the nail cap (2111) of the bolt (211) is not less than the sum of the diameter of the bolt rod (2112) and twice the thickness of the low elastic modulus material (212).

4. The one-way prestressed assembled frame with non-tensile composite floor slab according to claim 1, characterized in that: The low elastic modulus material (212) is rubber or foam plastic.

5. The one-way prestressed assembled frame with non-tensile composite floor slab according to claim 1, characterized in that: The steel beam (21) is an H-shaped steel beam or an H-shaped steel beam covered or partially covered with concrete.

6. The one-way prestressed assembled frame with non-tensile composite floor slab according to claim 1, characterized in that: The length of the prefabricated bottom plate (41) placed on the steel beam (21) is not less than the product of the maximum inter-story displacement angle of the floor and the beam height of the prefabricated concrete composite beam (3).

7. The one-way prestressed assembled frame with non-tension-resistant composite floor slab according to claim 1, characterized in that: The steel bars of the prefabricated bottom plate (41) and the steel bars of the post-cast concrete superimposed layer are located on the upper part of the steel beam (21), extending into the post-cast concrete superimposed layer of the steel-concrete superimposed beam (2) but not exceeding the center line of the steel beam (21).

8. The construction method of a one-way prestressed assembled frame with a non-tension-resistant composite floor slab according to any one of claims 1 to 7, characterized in that: The steps include: 1) The factory produces precast concrete columns (1), steel beams (21) welded with studs (211), precast beams (31) and precast base plates (41); 2) positioning the precast concrete column (1), the steel beam (21) and the precast beam (31) at the construction site, connecting the steel bracket (12) and the steel beam (21) by welding or bolting the precast concrete column (1) and the steel beam (21); and crimping the precast concrete column (1) and the precast beam (31) by tensioning prestressed tendons (5); 3) placing the four sides of the prefabricated bottom plate (41) on the steel beam (21) and the prefabricated beam (31), and embedding the low elastic modulus material (212) on the side of the stud (211), around the prefabricated concrete column (1) and at the center line of the upper part of the steel beam (21); 4) pouring concrete to form a post-cast concrete superimposed layer of the steel-concrete superimposed beam (2), the precast concrete superimposed beam (3) and the non-tension-resistant superimposed floor slab (4), and a concrete layer wrapped around the steel corbel (12).

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