A construction method of prefabricated outer wall at upturned beam

Abstract

This invention relates to the field of precast exterior wall construction technology with upturned beams, specifically to a method for constructing precast exterior walls at upturned beams, comprising the following steps: Step 1: Prepare two supporting steel bars; Step 2: Tie the lower steel bars of the upturned beam and fix the supporting steel bars to the lower part of the upturned beam; Step 3: Close the formwork and erect the beam and slab formwork, tie the beam and slab steel bars, and pour concrete; Step 4: Tie the upper steel bars of the upturned beam; Step 5: Hoist the precast exterior wall; Step 6: Fix the diagonal bracing of the precast exterior wall; Step 7: Tie the wall column steel bars of the precast exterior wall and the lower steel bars of the upturned beam at the top of the precast exterior wall and close the formwork; Step 8: Erect the remaining beam and slab formwork and pour concrete. This invention directly hoists the precast exterior wall to the upper steel bars of the upturned beam, and after tying the wall column steel bars on both sides of the upturned beam and the lower steel bars of the upturned beam at the top of the precast exterior wall, pours concrete together, reducing the traditional construction steps for precast exterior walls with upturned beams, shortening the construction cycle, and increasing the construction speed.

Description

Technical Field

[0001] This invention relates to the field of precast exterior wall construction technology with upturned beams, and particularly to a method for constructing precast exterior walls at upturned beams. Background Technology

[0002] The precast exterior walls (precast infill walls and precast shear walls) at the upturned beams must be hoisted after the upturned beams are poured. The precast exterior walls are generally connected to the lower structure via threaded blind holes or grouting sleeves. If the height of the upturned beam exceeds 500mm, pouring it as a whole presents significant challenges in formwork erection. Without secure support points, the outer formwork of the concrete is prone to misalignment. After demolding, the upturned beam needs to be chipped and repaired, and the pre-reserved reinforcing bars in the upturned beam may also shift, making it difficult to position the precast exterior walls during installation. If the upper and lower structures of the upturned beam are poured separately, after the lower structure is poured, the interface concrete must be chipped, the unpoured reinforcing bars of the upturned beam must be tied and fixed, formwork and supports must be erected, and then concrete must be poured. Hoisting of the precast exterior walls can only begin after the concrete reaches a certain strength. This process involves numerous steps, impacting the overall construction progress on site. This process, especially on each floor, significantly restricts the overall construction progress of the building. Summary of the Invention

[0003] To address the problem of insufficient fixed points for formwork support during the integral casting of upturned beams, this invention provides a method for constructing precast exterior walls at upturned beams. This method involves pre-embedding supporting reinforcing bars during the binding of the lower reinforcing bars of the upturned beam and then casting it into shape. After binding the upper reinforcing bars of the upturned beam, the precast exterior wall is directly hoisted onto the supporting reinforcing bars. Concrete is then poured together after binding the reinforcing bars of the wall columns on both sides of the upturned beam, the lower reinforcing bars of the upturned beam at the top of the precast exterior wall, and the supporting reinforcing bars. This reduces the number of construction steps in traditional upturned beam precast exterior wall construction, shortens the construction cycle, and increases construction speed.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for constructing a precast exterior wall at an upward-turning beam includes the following steps:

[0006] Step 1: Prepare at least two supporting steel bars, the lower part of which is bent to form a horizontal section and a vertical section;

[0007] Step 2: Tie the lower reinforcing bars of the upturned beam and fix the horizontal section of the supporting reinforcing bars to the lower reinforcing bars of the upturned beam;

[0008] Step 3: Close the formwork and set up the beam and slab formwork, lay and tie the beam and slab reinforcement bars, and pour concrete to form the lower structure of the upturned beam;

[0009] Step 4: Remove the laitance from the interface between the upper and lower structures of the upturned beam, straighten the vertical section of the supporting steel bars, lay out the lines, tie the upper steel bars of the upturned beam and fix the dowel bars;

[0010] Step 5: After completing the binding of the upper reinforcing bars of the upturned beam and the fixing of the dowel bars, the precast exterior wall is hoisted. The lower part of the precast exterior wall is provided with a groove that fits with the vertical end of the supporting reinforcing bar. The lower part of the precast exterior wall is also provided with a grouting hole so that the precast exterior wall is supported on the supporting reinforcing bar; the grouting hole is fitted into the dowel bar.

[0011] Step 6: After the prefabricated exterior wall is installed, adjust and fix the diagonal braces of the prefabricated exterior wall;

[0012] Step 7: Tie the wall column reinforcement on both sides of the precast exterior wall, the lower reinforcement of the upper flip beam and the supporting reinforcement of the precast exterior wall, close the formwork, and check the positioning and verticality of the precast exterior wall;

[0013] Step 8: Erect the formwork for the remaining beams and slabs, lay and tie the reinforcing steel bars for the beams and slabs, and then pour concrete.

[0014] Step 9: Grout the grouting holes that fit the reinforcing bars.

[0015] Furthermore, the diameter of the supporting reinforcing bars is ≥25mm, and the lower part of the supporting reinforcing bars is bent at 90° to form the horizontal and vertical sections. The horizontal section is used to fix the lower reinforcing bars of the upturned beam, and the upper part of the vertical section is used to support and position the precast exterior wall. By reserving supporting reinforcing bars when binding the lower reinforcing bars of the upturned beam, the positioning and support of the precast exterior wall can be achieved during hoisting, ensuring the stability of the precast exterior wall installation.

[0016] Furthermore, the length of the horizontal section is 150mm, and the length of the vertical section is 15d + the height of the upturned beam + the length of the supporting steel bar extending out of the upper part of the upturned beam, where d is the diameter of the supporting steel bar, and the supporting steel bar is C25 steel bar.

[0017] Furthermore, in step 2, the top of the vertical section of the supporting reinforcing bar is ground flat, and the vertical section of the supporting reinforcing bar is fixed with a positioning steel plate.

[0018] Furthermore, in step 2, horizontal hooks are fixed to the web reinforcement of the beam steel bars on both sides of the lower part of the upturned beam, at a distance of one-fifth from the end of the precast exterior wall, and at the web reinforcement of the floor structure elevation. The horizontal section and vertical end of the supporting reinforcement are spot-welded to the horizontal hooks, and the horizontal hooks are securely tied to the stirrups and longitudinal horizontal reinforcement. By fixing the horizontal hooks to the web reinforcement of the beam steel bars and spot-welding the supporting reinforcement to the hooks, the direct spot welding of the supporting reinforcement to the beam steel bars is prevented, thus avoiding any impact on the performance of the beam steel bars.

[0019] Furthermore, the groove at the bottom of the precast exterior wall has a diameter of 50mm and a depth equal to the length of the supporting steel bar extending from the top of the upturned beam. By setting a groove at the bottom of the precast exterior wall, the supporting steel bar fits into the groove, achieving positioning and support during the hoisting of the precast exterior wall and ensuring the overall stability of the structure.

[0020] Further, repeat steps 4 to 9 to complete the installation of the prefabricated exterior wall at the upturned beam layer by layer.

[0021] Furthermore, the prefabricated exterior wall has a weight of less than or equal to 1.2t and a length of less than or equal to 3 meters.

[0022] Furthermore, when the weight of the precast exterior wall exceeds 1.2t or its length exceeds 3 meters, a fixed support steel bar is added at the middle of the lower part of the upper beam during step 2 when tying the lower steel bars of the upper beam. By adjusting the number and arrangement of the support steel bars, it can adapt to precast exterior walls of different weights and sizes, exhibiting good engineering applicability.

[0023] Furthermore, in step 8, the reinforcing bars of the beams and slabs are laid and tied. After acceptance, concrete is poured. The poured concrete passes from top to bottom through the lower reinforcing bars and supporting reinforcing bars of the top upturned beam of the precast exterior wall, the reinforcing bars of the wall columns on both sides of the precast exterior wall, and the upper reinforcing bars of the upturned beam, so as to achieve one-time concrete pouring and complete the construction.

[0024] The beneficial effects of the present invention through the above technical solution are:

[0025] This invention involves pre-embedding supporting reinforcing bars during the lower part of the upturned beam before casting it into shape. After tying the upper part of the upturned beam's reinforcing bars, the precast exterior wall is directly hoisted onto the supporting reinforcing bars on the upper part of the upturned beam. Then, the reinforcing bars of the wall columns on both sides of the precast exterior wall, the lower part of the upturned beam's reinforcing bars, and the supporting reinforcing bars are tied together before pouring concrete. This reduces the construction steps and waiting time of traditional separate pouring, significantly shortening the construction cycle. It ensures rapid and stable installation of the precast exterior wall, improving on-site construction speed. The difficulty of formwork erection is reduced, avoiding the challenges of formwork erection during the overall pouring of the upturned beam, reducing the risk of formwork misalignment, and improving construction quality.

[0026] This invention provides reliable support points for hoisting precast exterior walls by fixing supporting reinforcing bars to both sides of the lower part of the upper beam during the binding of the lower reinforcing bars. Simultaneously, positioning steel plates are used for positioning, effectively solving the installation difficulties caused by reinforcing bar misalignment in traditional construction methods. This ensures the stability of the precast exterior wall during hoisting and improves construction safety.

[0027] This invention prevents the supporting steel bars from being directly welded to the main steel bars, thus avoiding affecting the performance of the main steel bars, by setting horizontal hooks on the web bars at both ends of the lower steel bars of the upper beam when tying the lower steel bars of the upper beam.

[0028] This invention adapts to prefabricated exterior walls of different weights and sizes by adjusting the number and arrangement of supporting steel bars when binding the lower steel bars of the upturned beam, thus exhibiting good engineering applicability. Attached Figure Description

[0029] Figure 1 This is a diagram of the lower part of the upturned beam and the supporting steel reinforcement structure of a precast exterior wall construction method at the upturned beam of the present invention.

[0030] Figure 2 This is a structural diagram of the upturned beam, supporting steel bars, and prefabricated exterior wall installation in a construction method for prefabricated exterior walls at the upturned beam location according to the present invention.

[0031] Figure 3 This is a prefabricated exterior wall structure diagram of a prefabricated exterior wall construction method for an upward-turning beam according to the present invention.

[0032] Figure 4 This invention relates to a method for constructing precast exterior walls at the upturned beam. Figure 3 Sectional view at point AA.

[0033] Figure 5 This is a vertical connection diagram of the precast exterior wall (before pouring) for a precast exterior wall construction method at the upturned beam of the present invention.

[0034] Figure 6 This is a vertical connection diagram of the precast exterior wall after concrete filling in a precast exterior wall construction method at the upturned beam of the present invention.

[0035] Figure 7 This is a diagram of the supporting steel bars and the precast exterior wall installation structure (before pouring) for a precast exterior wall construction method at the upturned beam of the present invention.

[0036] Figure 8 This is a schematic diagram of the installation of supporting steel bars and precast exterior wall after pouring concrete in a precast exterior wall construction method for an upward-turning beam according to the present invention.

[0037] The attached diagram is labeled as follows: 1. Lower part of the upturned beam, 2. Supporting steel bar, 3. Upper part of the upturned beam, 4. Diagonal brace fixing point, 5. Precast exterior wall, 6. Groove, 7. Inserted bar, 8. Grouting hole, 10. Floor slab. Detailed Implementation

[0038] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings:

[0039] like Figures 1 to 8 As shown, a method for constructing a precast exterior wall at an upward-turning beam includes the following steps:

[0040] Step 1: Prepare two supporting reinforcing bars 2, with a diameter ≥ 25mm. In this embodiment, the supporting reinforcing bars 2 are C25 steel bars. The supporting reinforcing bars 2 are bent at 90° to form a horizontal section and a vertical section; the horizontal section is 150mm long, and the vertical section is 15d + the height of the upturned beam + the length of the supporting reinforcing bar extending beyond the upturned beam, where d is the diameter of the reinforcing bar. The length of the supporting reinforcing bar 2 extending beyond the upper part 3 of the upturned beam ranges from 20mm to 50mm. In this embodiment, the length of the supporting reinforcing bar 2 extending beyond the upper part 3 of the upturned beam is 30mm. The horizontal section is used to fix the lower part 1 of the upturned beam with reinforcing bars, and the upper part of the vertical section is used to support the precast exterior wall 5. In this embodiment, the precast exterior wall 5 is a precast exterior wall 5 with a weight of less than or equal to 1.2t and a length of less than or equal to 3m. Its structure is the same as that of the existing precast exterior wall 5, and the similarities will not be repeated. The difference is that the lower part of the precast exterior wall 5 in this embodiment has a groove 6 with a diameter of 50mm and a depth equal to the length of the supporting reinforcing bar 2 extending from the upper part 3 of the upturned beam. In this embodiment, the depth of the groove is 30mm. Before construction, the top of the vertical end of the supporting reinforcing bar 2 is ground flat to ensure a good fit with the groove 6 of the precast exterior wall 5.

[0041] Step 2: Using the structural surface of floor slab 10 as the boundary, divide the upturned beam into an upper part 3 and a lower part 1. First, tie the reinforcing bars of the lower part 1. Horizontal hooks are fixed to the web reinforcement bars on both sides of the lower part 1, corresponding to a distance of one-fifth from the end of the precast exterior wall 5. Horizontal hooks are also fixed to the web reinforcement bars at the floor structural elevation. These horizontal hooks are existing hooks that can be fitted and fixed to the reinforcing bars; they are additional hooks for fixing. The horizontal sections of the supporting reinforcing bars 2 are spot-welded to the horizontal hooks on the web reinforcement bars on both sides of the lower part 1, corresponding to a distance of one-fifth from the end of the precast exterior wall 5. The vertical sections of the supporting reinforcing bars 2 are spot-welded to the horizontal hooks on the web reinforcement bars at the floor structural elevation. The horizontal hooks are securely tied to the stirrups and longitudinal horizontal reinforcing bars to ensure overall stability. Positioning steel plates are used to fix the position of the vertical reinforcing bars.

[0042] Step 3: After the concealed acceptance of the reinforcing steel of the lower part of the upturned beam 1 is passed, the formwork is closed, the formwork of the remaining beams and slabs is erected, and the reinforcing steel of the beams and slabs is laid and tied. After the acceptance is passed, concrete is poured into the tied reinforcing steel of the lower part of the upturned beam and the reinforcing steel of the beams and slabs. During the pouring process, special care is taken to avoid collision with the supporting reinforcing steel 2 to prevent it from deviating.

[0043] Step 4: After the concrete is poured, remove the laitance from the structural interface between the upper part 3 and the lower part 1 of the upturned beam, and correct the vertical position of the supporting steel bars 2 to ensure that their verticality meets the requirements. When the concrete strength reaches the point where construction workers can stand on the poured concrete without it collapsing, that is, when the concrete has solidified and its strength is greater than 1.25MPa, carry out the layout work, tie the steel bars of the upper part 3 of the upturned beam and fix the dowel bars 7.

[0044] Step 5: After completing the binding of the upper 3 reinforcing bars of the upturned beam and the fixing dowel bars 7, hoist the precast exterior wall 5. During hoisting, ensure that the groove 6 at the bottom of the precast exterior wall 5 is accurately fitted into the vertical section of the supporting reinforcing bar 2 to achieve positioning and support. Fit the grouting hole 8 onto the dowel bar 7.

[0045] Step 6: After hoisting is completed, adjust and fix the diagonal bracing in a timely manner to ensure the stability of the precast exterior wall 5 during subsequent construction.

[0046] Step 7: Tie the wall column reinforcement on both sides of the precast exterior wall 5, and tie the lower part 1 reinforcement of the upper beam and the supporting reinforcement 2 of the precast exterior wall 5. After the reinforcement is inspected and approved, the formwork is closed. After the vertical formwork is fixed, the positioning and verticality of the precast exterior wall 5 are rechecked to avoid positional deviations caused by the fixing of the surrounding formwork.

[0047] Step 8: Erect the formwork for the remaining beams and slabs, lay and tie the beam and slab reinforcement bars, and pour concrete after acceptance. The poured concrete passes from top to bottom through the lower 1 reinforcement bars and supporting reinforcement bars 2 of the top upturned beam of the precast exterior wall 5, the reinforcement bars of the wall columns on both sides of the precast exterior wall 5, and the upper 3 reinforcement bars of the upturned beam, achieving a one-time concrete pour to complete the construction. When pouring the upper 3 reinforcement bars of the upturned beam, the concrete overflows into the groove 6 of the supporting reinforcement bars 2 and the lower groove of the precast exterior wall 5, realizing the pouring of the bottom groove 6 of the precast exterior wall 5.

[0048] Step 9: Grout the grouting hole 8 that fits with the reinforcing bar 7. The grouting method is the same as the existing method for grouting reinforcing bars and grouting holes, so it will not be described again here.

[0049] Repeat steps 4 to 9 above to complete the installation of the precast exterior wall 5 at the upturned beam layer by layer, so as to achieve standardized and streamlined construction.

[0050] In this embodiment, steps 7 and 8 omit the mortar caulking step between the precast exterior wall 5 and the upturned beam, which is common in traditional construction methods. Instead, the wall is cast integrally after the upper 3 reinforcing bars of the upturned beam, the reinforcing bars of the wall columns on both sides of the precast exterior wall 5, the lower 1 reinforcing bars of the upturned beam above the precast exterior wall 5, and the supporting reinforcing bars 2 are tied together. The steps not mentioned in this embodiment are common knowledge and procedures in the construction of upturned beams and precast exterior walls 5, and are consistent with existing construction methods for upturned beams and precast exterior walls 5, so they will not be elaborated upon here.

[0051] When the weight of the precast exterior wall 5 is greater than 1.2t or the length is greater than 3m, when binding the lower part 1 of the upturned beam in step 2, a supporting steel bar 2 is added in the middle position of the beam steel bar and a groove 6 is added in the middle of the precast exterior wall to correspond to the supporting steel bar 2 in the middle position of the beam steel bar. The fixing method is the same as that of the supporting steel bars 2 on both sides to ensure that the supporting steel bars 2 are evenly stressed.

[0052] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention should be included within the scope of the present invention.

Claims

1. A method for constructing a precast exterior wall at an upward-turning beam, characterized in that, Includes the following steps: Step 1: Prepare at least two supporting steel bars (2), the lower part of which is bent to form a horizontal section and a vertical section; Step 2: Tie the reinforcing bars of the lower part (1) of the upturned beam, and fix the horizontal section of the supporting reinforcing bar (2) to the reinforcing bars of the lower part (1) of the upturned beam; Step 3: Close the formwork and set up the beam and slab formwork, lay and tie the beam and slab reinforcement, pour concrete to form the lower part (1) structure of the upturned beam; Step 4: Remove the slurry from the interface between the upper part (3) and the lower part (1) of the upturned beam, correct the vertical section of the supporting steel bar (2), lay out the line, tie the steel bar of the upper part (3) of the upturned beam and fix the dowel bar (7). Step 5: After completing the binding of the upper part (3) of the upturned beam and the fixing of the dowel bars (7), the precast exterior wall (5) is hoisted. The lower part of the precast exterior wall (5) is provided with a groove (6) that fits with the vertical end of the supporting steel bar (2). The lower part of the precast exterior wall (5) is also provided with a grouting hole (8) so that the precast exterior wall (5) is supported on the supporting steel bar (2) and the grouting hole (8) is inserted into the dowel bar (7). Step 6: After the prefabricated exterior wall (5) is installed, adjust and fix the diagonal bracing of the prefabricated exterior wall (5); Step 7: Tie the wall column reinforcement on both sides of the precast exterior wall (5) and the reinforcement of the lower part (1) of the upper beam of the precast exterior wall (5) and the supporting reinforcement (2), close the formwork, and check the positioning and verticality of the precast exterior wall (5); Step 8: Erect the formwork for the remaining beams and slabs, lay and tie the reinforcing steel bars for the beams and slabs, and then pour concrete. Step 9: Grout the grouting hole (8) that fits with the reinforcing bar (7).

2. The method for constructing a precast exterior wall at an upward-turning beam according to claim 1, characterized in that, The diameter of the supporting steel bar (2) is ≥25mm. The lower part of the supporting steel bar (2) is bent at 90° to form the horizontal section and the vertical section. The horizontal section is used to fix the lower part (1) of the upturned beam, and the upper part of the vertical section is used to support the positioning of the prefabricated exterior wall (5).

3. The method for constructing a precast exterior wall at an upward-turning beam according to claim 2, characterized in that, The length of the horizontal section is 150mm, and the length of the vertical section is 15d + height of the upturned beam + length of the supporting steel bar (2) extending out of the upper part (3) of the upturned beam, where d is the diameter of the supporting steel bar (2) and the supporting steel bar (2) is a C25 steel bar.

4. The method for constructing a precast exterior wall at an upward-turning beam according to claim 1, characterized in that, In step 2, the top of the vertical section of the supporting steel bar (2) is ground flat, and the vertical section of the supporting steel bar (2) is fixed with a positioning steel plate.

5. The method for constructing a precast exterior wall at an upward-turning beam according to claim 1, characterized in that, In step 2, horizontal hooks are fixed on the web of the beam reinforcement corresponding to the lower part (1) of the upturned beam, one-fifth of the distance from the end of the precast outer wall (5), and the web of the floor structure elevation. The horizontal section and vertical end of the supporting reinforcement (2) are spot welded to the horizontal hooks. The horizontal hooks are firmly tied to the stirrups and longitudinal horizontal reinforcement.

6. The method for constructing a precast exterior wall at an upward-turning beam according to claim 1, characterized in that, The groove (6) at the bottom of the precast exterior wall (5) has a diameter of 50mm and a depth equal to the length of the supporting steel bar (2) extending out of the upper part (3) of the upturned beam.

7. The method for constructing a precast exterior wall at an upward-turning beam according to claim 1, characterized in that, Repeat steps 4 to 9 to complete the installation of the prefabricated exterior wall (5) at the upturned beam layer by layer.

8. The method for constructing a precast exterior wall at an upward-turning beam according to claim 1, characterized in that, The weight of the prefabricated exterior wall (5) is less than or equal to 1.2t and the length is less than or equal to 3 meters.

9. A method for constructing a precast exterior wall at an upward-turning beam according to claim 1, characterized in that, When the weight of the precast exterior wall (5) is greater than 1.2t or the length is greater than 3 meters, when binding the reinforcing bars of the lower part (1) of the upturned beam in step 2, a fixed support reinforcing bar (2) is added in the middle of the lower part (1) of the upturned beam.

10. A method for constructing a precast exterior wall at an upward-turning beam according to claim 1, characterized in that, In step 8, the reinforcing bars of the beam and slab are laid and tied. After the acceptance is qualified, the concrete is poured. The poured concrete passes from top to bottom through the reinforcing bars of the lower part (1) of the top upturned beam of the precast exterior wall (5) and the supporting reinforcing bars (2), the reinforcing bars of the wall columns on both sides of the precast exterior wall (5), and the reinforcing bars of the upper part (3) of the upturned beam, thus completing the construction.

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