An enhanced horizontal joint structure capable of suppressing concentrated opening of the horizontal joint of a laminated shear wall

Abstract

The present invention discloses an enhanced horizontal joint structure capable of suppressing the concentrated opening of the horizontal joint of a composite shear wall. Special joint-enhancing vertical steel bars are arranged at the floor position in the cavity of the composite hidden column of the precast wall. The lengths of the joint-enhancing vertical steel bars extending into the upper and lower precast walls can be taken as 10 to 20 times the diameter of the joint-enhancing vertical steel bars, which is significantly shorter than the lap length of the additional vertical connecting steel bars of the edge member and the vertical steel bars of the edge member in the precast wall. The total area of the joint-enhancing vertical steel bars should not exceed 40% of the additional vertical connecting steel bars of the edge member. The present invention can effectively avoid the formation of a weak section and concentrated opening at the bottom horizontal joint position of the precast wall under the action of lateral force. Compared with the existing enhanced horizontal joint structure that only increases the diameter or number of additional vertical connecting steel bars of the edge member, the amount of joint-enhancing vertical steel bars is less, which is convenient for on-site construction. The crack distribution and plastic development in the steel bar lapping area of the precast wall are more uniform, and the suppression of the concentrated opening of the horizontal joint is more efficient.

Description

Technical Field

[0001] The present invention belongs to the field of building technology, relates to a composite shear wall, and particularly relates to an enhanced horizontal joint structure capable of suppressing the concentrated opening of the horizontal joint of the composite shear wall. Background Art

[0002] The composite shear wall structure is provided with a cavity or a vertical duct in the middle of the precast wall, and the vertical steel bars of the upper and lower precast walls are indirectly lapped. It has the advantages of low cost, convenient connection and easy control of construction quality. It is increasingly used in the prefabricated residential buildings in our country. Representative systems include double-sided composite shear wall structure, SPCS welded steel mesh composite shear wall, EVE precast hollow slab shear wall and longitudinal rib composite shear wall, etc.

[0003] When a composite shear wall structure is adopted in a residential building, in order to achieve prefabricated construction, it is often necessary to precast the edge members of the shear wall and the wall body as a whole on the north and south exterior walls and the sides of the interior wall openings of the building. Inevitably, a composite concealed column needs to be adopted, that is, precast concrete wall panels are used on both sides of the edge member, and a cavity is reserved in the middle. Vertical steel bars, stirrups and tie bars of the edge member that do not extend out of the precast wall are arranged in the precast concrete wall panels on both sides. During on-site construction, additional vertical connecting steel bars of the edge member are arranged at the floor position in the cavity area of the composite concealed column. After pouring the post-cast concrete in the cavity, the additional vertical connecting steel bars of the edge member are indirectly lapped with the vertical steel bars of the edge member in the upper and lower precast walls one by one. The precast concrete wall panels on both sides of the composite concealed column area and the post-cast concrete in the cavity form an integral composite concealed column to participate in the structural force. The diameter and number of the additional vertical connecting steel bars of the edge member are the same as those of the vertical steel bars of the edge member in the upper and lower precast walls.

[0004] The steel bar area of the additional vertical connecting steel bars of the edge member and the vertical steel bars of the edge member in the precast wall in the lap joint area is twice that of the vertical steel bars in the non-lap joint area. The area and strength of the lap joint area are significantly larger than those of the non-lap joint area. The upper and lower cross-sections of the lap joint area will become weak cross-sections. Experimental studies have shown that under the action of lateral forces, the horizontal joint at the bottom of the precast wall with a low axial compression ratio will concentrate and open, weakening the seismic performance of the wall. Most of the existing enhanced horizontal joint structures only strengthen the connection structure in the superimposed hidden column area by increasing the diameter or number of additional vertical connecting steel bars of the edge member, without changing the length of the additional vertical connecting steel bars of the edge member extending into the upper and lower precast walls (see Chong X, Xie L, Ye X, et al. Experimental study on the seismic performance of superimposed RC shear walls with enhanced horizontal joints. Journal of Earthquake Engineering, 2017, (5): 1-17. and Wang Jingqiu. Research on the seismic performance of double-sided superimposed shear walls with different axial compression ratios. Dalian: Dalian University of Technology, 2019.). The test results show that the above enhanced horizontal joint structure cannot effectively inhibit the opening of the horizontal joint, and at the same time, it is easy to form a weak cross-section above the vertical steel bar lap joint area and cause concentrated damage, and it cannot fundamentally change the adverse effects of the vertical steel bar lap joint on the plastic distribution and mechanical properties of the plastic hinge area of the precast wall. Moreover, it has the disadvantages of large steel bar consumption, difficult construction in the joint area, and complex design process and is difficult to promote. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings of the horizontal joint structure of the precast wall in the existing superimposed shear wall structure, the purpose of the present invention is to provide an enhanced horizontal joint structure that can inhibit the concentrated opening of the horizontal joint of the superimposed shear wall, without changing the production and on-site construction technology of the precast wall. Only by adding special joint-enhancing vertical steel bars on the basis of the existing additional vertical connecting steel bars of the edge member in the superimposed hidden column area, the weak cross-section formed by the lap joint of the additional vertical connecting steel bars of the edge member and the vertical steel bars of the edge member in the precast wall can be transferred upward from the horizontal joint at the bottom of the precast wall, avoiding the concentrated opening of the horizontal joint at the bottom of the precast wall under the action of lateral forces and affecting the seismic performance of the wall. Compared with the existing structure, the present invention can more effectively inhibit the concentrated opening of the horizontal joint. Under the action of lateral forces, the crack distribution and plastic development in the steel bar lap joint area of the precast wall are more uniform, avoiding the formation of a weak cross-section above the vertical steel bar lap joint area and concentrated damage, and having less steel bar consumption and being convenient for on-site construction. Only need to design according to the structural requirements recommended by the present invention, without the need to perform cumbersome force calculations to determine the area of the joint-enhancing vertical steel bars.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] An enhanced horizontal joint structure for suppressing the concentrated opening of the horizontal joint of a composite shear wall, which is used for the enhanced connection of the overlapping concealed column area 1 of the upper and lower shear walls in a composite shear wall structure. The overlapping concealed column area 1 includes two layers of precast concrete wall panels 11, a cavity 12 is formed between the two layers of precast concrete wall panels 11. Vertical reinforcement bars 13 of the edge members, stirrups 16 of the edge members and tie bars 17 of the edge members that do not extend out of the precast wall are arranged in the precast concrete wall panel 11. Additional vertical connecting reinforcement bars 14 of the edge members and enhanced vertical reinforcement bars 15 of the joint are arranged at the floor position in the cavity 12 of the overlapping concealed column area 1. The enhanced vertical reinforcement bars 15 of the joint transfer the stress-weak section formed by the lap joint of the additional vertical connecting reinforcement bars 14 of the edge members and the vertical reinforcement bars 13 of the edge members upward from the horizontal joint 6 at the bottom of the precast wall, avoiding the concentrated opening of the horizontal joint 6 at the bottom of the precast wall under the action of lateral force and affecting the seismic performance of the wall.

[0008] The additional vertical connecting reinforcement bars 14 of the edge members are arranged during on-site construction.

[0009] After pouring the post-cast concrete in the cavity 12, the precast concrete wall panel 11 and the post-cast concrete in the cavity 12 form an overlapping concealed column to participate in the structural force. The diameter and number of the additional vertical connecting reinforcement bars 14 of the edge members in the cavity 12 are the same as those of the vertical reinforcement bars 13 of the edge members in the upper and lower precast walls, and are lap-connected with the vertical reinforcement bars 13 of the edge members in the upper and lower layers one by one. The additional vertical connecting reinforcement bars 14 of the edge members are not continuous in the cavity 12, and the length extending into the upper and lower precast walls meets the requirements of lap joint force transfer.

[0010] The enhanced vertical reinforcement bars 15 of the joint are arranged in a single row along the center line of the cavity 12, and are staggered in the center distance from the additional vertical connecting reinforcement bars 14 of the edge members in the wall width direction. They are not continuous in the upper and lower parts of the cavity 12, and the length extending into the upper and lower precast walls is significantly shorter than the lap length of the additional vertical connecting reinforcement bars 14 of the edge members and the vertical reinforcement bars 13 of the edge members.

[0011] The enhanced vertical reinforcement bars 15 of the joint are staggered in the center distance from the additional vertical connecting reinforcement bars 14 of the edge members by 50 mm in the wall width direction, and the length extending into the upper and lower precast walls is taken as 10 - 20 times the diameter of the enhanced vertical reinforcement bars 15 of the joint.

[0012] The strength grade of the enhanced vertical reinforcement bars 15 of the joint is the same as that of the additional vertical connecting reinforcement bars 14 of the edge members, and the total area does not exceed 40% of the total area of the additional vertical connecting reinforcement bars 14 of the edge members.

[0013] When the diameter of the enhanced vertical reinforcement bars 15 of the joint is the same as that of the additional vertical connecting reinforcement bars 14 of the edge members, when 6 or 8 additional vertical connecting reinforcement bars 14 of the edge members are arranged in the overlapping concealed column area 1, 2 or 3 enhanced vertical reinforcement bars 15 of the joint are respectively arranged.

[0014] The vertical reinforcing bars 15 for joint enhancement adopt straight reinforcing bars or reinforcing bars with 90° hooks at both ends to enhance their anchorage performance in the post-cast concrete of the cavity 12.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) Compared with the existing horizontal joint structure without enhancement, the present invention can transfer the weak stress section formed by the lap joint of the additional vertical connecting reinforcing bars of the edge member and the vertical reinforcing bars of the edge member in the precast wall upward from the bottom horizontal joint of the precast wall, avoiding the concentrated opening of the bottom horizontal joint of the precast wall under the action of lateral force and affecting the seismic performance of the wall.

[0017] (2) Compared with the existing enhanced horizontal joint structure that only increases the diameter or number of additional vertical connecting reinforcing bars of the edge member, the length of the vertical reinforcing bars for joint enhancement extending into the precast wall in the present invention is significantly shorter than that of the additional vertical connecting reinforcing bars of the edge member, which can more effectively inhibit the concentrated opening of the horizontal joint and avoid the formation of a weak section and concentrated failure above the vertical reinforcing bar lap joint area.

[0018] (3) Compared with the existing enhanced horizontal joint structure that only increases the diameter or number of additional vertical connecting reinforcing bars of the edge member, the present invention uses less reinforcing steel and is convenient for on-site construction, avoiding the interference of too many and too long vertical reinforcing bars for joint enhancement on the vibration of the post-cast concrete.

[0019] (4) Compared with the existing enhanced horizontal joint structure that only increases the diameter or number of additional vertical connecting reinforcing bars of the edge member, the vertical reinforcing bars for joint enhancement in the present invention only need to be designed according to the recommended structural requirements without complicated stress calculation, which is convenient for engineering design and engineering application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a three-dimensional schematic diagram of an enhanced horizontal joint structure for suppressing the concentrated opening of the horizontal joint of a composite shear wall according to the present invention.

[0021] Figure 2 is Figure 1 the schematic diagram of the A-A cross-section in

[0022] Figure 3 is Figure 1 the schematic diagram of the B-B cross-section in

[0023] Figure 4 is the schematic diagram of the enhanced horizontal joint structure when 8 vertical reinforcing bars of the edge member are configured in the edge member.

[0024] Figure 5 is Figure 1 the improved type of the vertical reinforcing bars for joint enhancement of the enhanced horizontal joint structure shown.

[0025] Figure 6 For Figure 1 Comparative Example 1 of the enhanced horizontal joint structure shown, i.e., a three-dimensional schematic diagram of an existing composite shear wall without an enhanced horizontal joint structure.

[0026] Figure 7 For Figure 6 The schematic diagram of the C-C section in

[0027] Figure 8 For Figure 6 The schematic diagram of the D-D section in

[0028] Figure 9 For Figure 1 Comparative Example 2 of the enhanced horizontal joint structure shown, i.e., a three-dimensional schematic diagram of an existing enhanced horizontal joint structure of a composite shear wall.

[0029] Figure 10 For Figure 9 The schematic diagram of the E-E section in

[0030] In the figure: 1 - Composite concealed column area; 2 - Wall body area; 3 - Upper precast wall; 4 - Lower precast wall; 5 - Floor slab; 6 - Horizontal joint at the bottom of the precast wall; 7 - Horizontal post-cast strip at the top of the precast wall; 11 - Precast concrete wall panel; 12 - Cavity; 13 - Vertical reinforcement of the inner edge member of the precast wall; 14 - Additional vertical connection reinforcement of the edge member; 15 - Joint-enhanced vertical reinforcement; 16 - Stirrups of the edge member; 17 - Tie bars of the edge member; 21 - Horizontal distribution reinforcement; 22 - Vertical distribution reinforcement. Specific embodiments

[0031] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples.

[0032] As Figures 1 to 5 shown, the composite shear wall includes a composite concealed column area 1 and a wall body area 2. Above and below the floor slab 5 are an upper precast wall 3 and a lower precast wall 4 respectively. The composite concealed column area 1 includes two layers of front and rear precast concrete wall panels 11. A cavity 12 is formed between the two layers of precast concrete wall panels 11. The precast concrete wall panels 11 are provided with horizontal distribution reinforcement 21, vertical distribution reinforcement 22, vertical reinforcement 13 of the inner edge member of the precast wall that does not extend out of the precast wall, stirrups 16 of the edge member, and tie bars 17 of the edge member.

[0033] An enhanced horizontal joint structure for suppressing the concentrated opening of the horizontal joint of a composite shear wall, which is used for the enhanced connection of the composite concealed column area 1 of the upper and lower shear walls in a composite shear wall structure. During on-site construction, additional vertical connecting steel bars 14 for edge members are arranged at the floor position in the cavity 12 of the composite concealed column area 1. Along the horizontal post-cast strip 7 at the top of the precast wall, after pouring the post-cast concrete in the cavity 12, the precast concrete wall panel 11 and the post-cast concrete in the cavity 12 form a composite concealed column to participate in the structural force. The diameter and number of the additional vertical connecting steel bars 14 for edge members in the cavity 12 are the same as those of the vertical steel bars 13 of the edge members in the upper precast wall 3 and the lower precast wall 4, and are lap-connected with the vertical steel bars 13 of the edge members in the upper and lower layers one by one. The additional vertical connecting steel bars 14 for edge members are discontinuous in the cavity 12, and the lengths extending into the upper and lower precast walls meet the requirements of steel bar lap force transfer. According to the requirements of the on-site design specifications, the lengths of the additional vertical connecting steel bars 14 for edge members extending into the upper and lower precast walls are not less than 40 times the diameter of the additional vertical connecting steel bars 14 for edge members.

[0034] The present invention optimizes and improves the connection structure of the horizontal joint composite concealed column area 1. On the basis of the existing additional vertical connecting steel bars 14 for edge members in the composite concealed column area 1, special joint-enhancing vertical steel bars 15 are added, and the weak force-bearing section formed by the lap joint of the additional vertical connecting steel bars 14 for edge members and the vertical steel bars 13 of the edge members in the precast wall is transferred upward from the horizontal joint 6 at the bottom of the precast wall, so as to avoid the concentrated opening at the position of the horizontal joint 6 at the bottom of the precast wall under the action of lateral force, thereby affecting the seismic performance of the wall.

[0035] As Figure 1 、 Figure 2 shown, the joint-enhancing vertical steel bars 15 are arranged at the floor position in the cavity 12 of the composite concealed column area 1, arranged in a single row along the center line of the cavity 12, and the center distance from the additional vertical connecting steel bars 14 for edge members is staggered by about 50 mm in the direction of the wall width. They are discontinuous in the upper and lower parts of the cavity 12, and the lengths extending into the upper and lower precast walls can be taken as 10 to 20 times the diameter of the joint-enhancing vertical steel bars 15, which is significantly shorter than the lap length of the additional vertical connecting steel bars 14 for edge members and the vertical steel bars 13 of the edge members, so as to avoid the formation of a weak section above the additional vertical connecting steel bars for edge members and the occurrence of concentrated failure.

[0036] Specifically, the strength grade of the joint-enhancing vertical steel bars 15 is the same as that of the additional vertical connecting steel bars 14 for edge members, and the total area should not exceed 40% of the total area of the additional vertical connecting steel bars 14 for edge members. When the diameter of the joint-enhancing vertical steel bars 15 is the same as that of the additional vertical connecting steel bars 14 for edge members, as Figure 1 、 Figure 2, in a specific embodiment of the present invention shown in Figure 3, when 6 additional vertical connecting steel bars 14 of the edge member are arranged in the superposed concealed column area 1, 2 vertical steel bars 15 for joint enhancement are arranged; as Figure 4 shown in another specific embodiment of the present invention, when 8 additional vertical connecting steel bars 14 of the edge member are arranged in the superposed concealed column area 1, 3 vertical steel bars 15 for joint enhancement are arranged.

[0037] Figure 1 , Figure 2 , Figure 3 In the specific embodiment of the present invention shown, the vertical steel bars 15 for joint enhancement adopt straight steel bars. Further, as Figure 5 shown, the vertical steel bars 15 for joint enhancement can also adopt steel bars with 90° hooks at both ends to enhance their anchorage performance in the post-cast concrete of the cavity 12.

[0038] Figure 6 , Figure 7 , Figure 8 shows the existing horizontal joint structure of the superposed shear wall without enhancement, that is, Comparative Example 1 of the present invention. Figure 9 , Figure 10 shows the enhanced horizontal joint structure of the existing superposed shear wall with only the number of additional vertical connecting steel bars of the edge member increased, that is, Comparative Example 2 of the present invention. The present invention is compared with Comparative Example 1 and Comparative Example 2, as shown in Table 1.

[0039] Table 1

[0040]

[0041] In summary, the present invention arranges special vertical steel bars 15 for joint enhancement at the floor position in the cavity of the superposed concealed column of the precast wall. The length of the vertical steel bars 15 for joint enhancement extending into the upper and lower precast walls can be taken as 10 - 20 times the diameter of the vertical steel bars 15 for joint enhancement, which is significantly shorter than the lap length of the additional vertical connecting steel bars of the edge member and the vertical steel bars of the edge member in the precast wall. The total area of the vertical steel bars 15 for joint enhancement should not exceed 40% of the additional vertical connecting steel bars of the edge member. The present invention can effectively prevent the formation of a weak section and concentrated opening at the bottom horizontal joint position of the precast wall under the action of lateral force. Compared with the existing enhanced horizontal joint structure that only increases the diameter or the number of additional vertical connecting steel bars of the edge member, the amount of the vertical steel bars 15 for joint enhancement is less, which is convenient for on-site construction. The crack distribution and plastic development in the steel bar lap area of the precast wall are more uniform, and the inhibition of concentrated opening at the horizontal joint is more efficient.

[0042] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes and substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An enhanced horizontal joint structure for suppressing the concentrated opening of the horizontal joint of a composite shear wall, which is used for the enhanced connection of the overlapping concealed column area (1) of the upper and lower shear walls in a composite shear wall structure. The overlapping concealed column area (1) includes two layers of precast concrete wall panels (11) in the front and back. A cavity (12) is formed between the two layers of precast concrete wall panels (11). Vertical reinforcement bars (13) of the edge member, stirrups (16) of the edge member, and tie bars (17) of the edge member that do not extend out of the precast wall are arranged in the precast concrete wall panel (11). It is characterized in that, At the floor position in the cavity (12) of the superimposed concealed column area (1), additional vertical connecting steel bars (14) for the boundary element and vertical steel bars (15) for joint strengthening are arranged. The vertical steel bars (15) for joint strengthening transfer the stress-weakened section formed by the lap joint of the additional vertical connecting steel bars (14) for the boundary element and the vertical steel bars (13) of the boundary element upward from the horizontal joint (6) at the bottom of the precast wall, avoiding the concentrated opening of the horizontal joint (6) at the bottom of the precast wall under the action of lateral forces and affecting the seismic performance of the wall. Among them, the diameter and number of the additional vertical connecting steel bars (14) for the boundary element in the cavity (12) are the same as those of the vertical steel bars (13) of the boundary element in the upper and lower precast walls. The vertical steel bars (15) for joint strengthening are arranged in a single row along the center line of the cavity (12), and the center distance is staggered with that of the additional vertical connecting steel bars (14) for the boundary element in the wall width direction. The length extending into the upper and lower precast walls is significantly shorter than the lap length of the additional vertical connecting steel bars (14) for the boundary element and the vertical steel bars (13) of the boundary element.

2. The enhanced horizontal joint structure capable of suppressing the concentrated opening of the horizontal joint of the laminated shear wall according to claim 1, characterized in that The additional vertical connecting steel bars (14) for the boundary element are arranged during on-site construction.

3. The enhanced horizontal joint structure capable of suppressing the concentrated opening of the horizontal joint of the laminated shear wall according to claim 1 or 2, characterized in that, After pouring the post-cast concrete in the cavity (12), the precast concrete wall panel (11) and the post-cast concrete in the cavity (12) form a superimposed concealed column to participate in the structural force. The additional vertical connecting steel bars (14) for the boundary element in the cavity (12) are lap-connected with the vertical steel bars (13) of the boundary element in the upper and lower layers one by one. The additional vertical connecting steel bars (14) for the boundary element are not continuous in the cavity (12), and the length extending into the upper and lower precast walls meets the requirements of steel bar lap force transfer.

4. The enhanced horizontal joint structure capable of suppressing the concentrated opening of the horizontal joint of the laminated shear wall according to claim 1, characterized in that The vertical steel bars (15) for joint strengthening are not continuous up and down in the cavity (12).

5. The enhanced horizontal joint structure according to claim 4, which can inhibit the concentrated opening of the horizontal joint of the laminated shear wall, is characterized in that The center distance of the vertical steel bars (15) for joint strengthening is staggered by 50 mm with that of the additional vertical connecting steel bars (14) for the boundary element in the wall width direction, and the length extending into the upper and lower precast walls is taken as 10 - 20 times the diameter of the vertical steel bars (15) for joint strengthening.

6. The enhanced horizontal joint structure capable of suppressing the concentrated opening of the horizontal joint of the laminated shear wall according to claim 1 or 4 or 5, characterized in that, The strength grade of the vertical steel bars (15) for joint strengthening is the same as that of the additional vertical connecting steel bars (14) for the boundary element, and the total area does not exceed 40% of the total area of the additional vertical connecting steel bars (14) for the boundary element.

7. The enhanced horizontal joint structure capable of suppressing the concentrated opening of the horizontal joint of the laminated shear wall according to claim 6, characterized in that When the diameter of the vertical steel bars (15) for joint strengthening is the same as that of the additional vertical connecting steel bars (14) for the boundary element, when 6 or 8 additional vertical connecting steel bars (14) for the boundary element are arranged in the superimposed concealed column area (1), 2 or 3 vertical steel bars (15) for joint strengthening are respectively arranged.

8. The enhanced horizontal joint structure capable of suppressing concentrated opening of the horizontal joint of the laminated shear wall according to claim 1, characterized in that, The vertical steel bars (15) for joint strengthening are straight steel bars, or steel bars with 90° hooks at both ends are used to enhance their anchorage performance in the post-cast concrete in the cavity (12).

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