A combined special-shaped column frame-confined concrete shear wall structure

Abstract

The present invention discloses a combined special-shaped column frame-confined concrete shear wall structure, belonging to the technical field of steel-concrete combination. The present invention includes a wall body, one end of the wall body is provided with a concrete-filled steel tube column, and a first connecting steel plate is provided on the concrete-filled steel tube column, and the other end is provided with a π-shaped steel; wherein, two first connecting steel plates are provided, corresponding to the two flanges of the π-shaped steel respectively, and the first connecting steel plate and the flange of the π-shaped steel are connected by connecting stirrups. By arranging the concrete-filled steel tube column and the π-shaped steel at both ends of the wall body, the present invention can be used as a confined edge member to enhance the performance of the wall body. At the same time, a PBL shear key is formed by connecting the two with connecting stirrups, so that the two can work together, further improving the seismic performance of the wall body, and thus being applicable to high-rise buildings. In addition, by hiding the concrete-filled steel tube column and the π-shaped steel in the wall body, the column body is not exposed and occupies a small space, increasing the indoor usable space.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel-concrete composite technology, and more specifically, relates to a composite special-shaped column border-constrained concrete shear wall structure. Background Art

[0002] A shear wall is also called a wind-resistant wall, seismic wall or structural wall. A shear wall is a wall in a building or structure that mainly bears the horizontal load and vertical load (gravity) caused by wind load or seismic action, and this wall can prevent the structural shear failure. Existing shear walls are generally made of reinforced concrete, and its purpose is to use reinforced concrete wall panels to replace the beams and columns in the frame structure to bear the internal forces caused by various loads and can effectively control the horizontal force of the structure.

[0003] Existing concrete shear wall components mostly have problems such as a lot of on-site wet operations, large component weight, and difficult construction. At the same time, due to the limitation of its seismic performance, when applied to high-rise / super high-rise buildings, the wall section thickness is large and the wall body is long, resulting in a smaller indoor usable space.

[0004] After retrieval, the application case with the Chinese patent publication number of CN 209129208 U discloses an L-shaped shear wall skeleton and a steel-concrete L-shaped shear wall. The L-shaped shear wall skeleton of this application case includes a steel wall head, a first rectangular steel pipe, a first horizontally distributed steel bar, a second horizontally distributed steel bar, a first steel border, a second steel border and a vertically distributed steel bar. In this application case, the steel-concrete L-shaped shear wall is prefabricated in the factory. First, the L-shaped shear wall skeleton is prepared, and then the L-shaped shear wall skeleton is clamped with templates and concrete is poured to obtain a prefabricated steel-concrete L-shaped shear wall component. Both the L-shaped shear wall skeleton and the steel-concrete L-shaped shear wall of this application case are completed in the factory, which can reduce on-site wet operations and is easy to construct, shortening the construction period by at least half. However, its seismic performance, the collaborative working performance of the steel pipe and the cast-in-place concrete, and the collaborative effect between the steel structures on both sides of the shear wall still need to be further improved. Summary of the Invention

[0005] 1. Problems to be Solved

[0006] In view of at least some of the above problems existing in the prior art, the present invention proposes a composite special-shaped column border-constrained concrete shear wall structure, aiming to solve the problems that the seismic performance of existing concrete shear wall components is limited, and it is easy to occupy part of the usable space when used in high-rise / super high-rise buildings, which is not conducive to the flexible layout of building house types.

[0007] 2. Technical Solutions

[0008] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0009] A combined special-shaped column frame-confined concrete shear wall structure of the present invention includes a wall body. One end of the wall body is provided with a concrete-filled steel tube column, and a first connecting steel plate is provided on the concrete-filled steel tube column. The other end is provided with a π-shaped steel. Among them, two first connecting steel plates are provided, corresponding to the two flanges of the π-shaped steel respectively. The first connecting steel plate and the flange of the π-shaped steel are connected by connecting stirrups.

[0010] Further, the wall bodies are connected in the horizontal direction through horizontal connection nodes. The horizontal connection nodes include L-shaped steels provided on the π-shaped steels. The two L-shaped steels on the connected wall bodies are symmetrically arranged at the center. An elastic cushion block is provided at the connection of the two L-shaped steels, and concrete is cast later.

[0011] Further, the wall bodies are connected in the horizontal direction through horizontal connection nodes. The horizontal connection nodes include a second connecting steel plate provided on the π-shaped steel of one side wall body and a third connecting steel plate provided on the π-shaped steel of the other side wall body. The second connecting steel plate and the third connecting steel plate are arranged in a staggered and overlapping manner, and are connected by bolts, and concrete is cast later.

[0012] Further, one second connecting steel plate is provided, and two third connecting steel plates are provided. And the free end of the second connecting steel plate extends into the gap between the two third connecting steel plates.

[0013] Further, the concrete-filled steel tube column includes a steel tube, centrifugally formed concrete provided in the steel tube, and core concrete provided in the centrifugally formed concrete. Among them, the centrifugally formed concrete is prefabricated in a factory, and the core concrete is formed by on-site casting.

[0014] Further, the strength of the core concrete is C30 - C60, and the strength of the centrifugally formed concrete does not exceed C120.

[0015] Further, the concrete-filled steel tube columns are connected in the vertical direction through vertical connection nodes. The vertical connection nodes include ring ribs and connecting steel bars. Among them, the ring ribs are provided on the inner wall of the steel tube and close to the end of the steel tube. A plurality of connecting steel bars are distributed annularly. One end of them is located inside the steel tube, and the other end extends outside the steel tube. After the casting is completed, the ring ribs play an anchoring role on the connecting steel bars.

[0016] Further, end plates are provided at the ends of the connecting steel bars. The end plates include long end plates and short end plates. Among them, the end of the long end plate abuts against the inner wall of the steel tube.

[0017] Further, an annular erection steel bar is provided in the space surrounded by the plurality of connecting steel bars, and multiple groups of the erection steel bars are arranged along the length direction of the connecting steel bars.

[0018] Furthermore, support bars are provided on the outer side of the connecting steel bars, and the connecting steel bars are positioned on the ring ribs through these support bars.

[0019] 3. Beneficial effects

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) For the combined special-shaped column frame-confined concrete shear wall structure of the present invention, by arranging concrete-filled steel tubes and π-shaped steel at both ends of the wall, it can be used as a confined edge member to enhance the performance of the wall. At the same time, a PBL shear key is formed by connecting them with connecting stirrups, enabling them to work together, which can further improve the seismic performance of the wall, thus being applicable to high-rise buildings. In addition, by hiding the concrete-filled steel tubes and π-shaped steel inside the wall, the columns are not exposed and occupy little space, which can increase the indoor usable space and enhance the flexibility of apartment layout.

[0022] (2) For the combined special-shaped column frame-confined concrete shear wall structure of the present invention, taking advantage of the characteristics of the π-shaped steel, L-shaped steel is welded to the π-shaped steel at the end of the shear wall, then the two L-shaped steels are spliced, and a rubber block is arranged at the splicing position, and then concrete is poured to enable the shear wall connection node to have sufficient energy dissipation capacity under large earthquakes.

[0023] (3) For the combined special-shaped column frame-confined concrete shear wall structure of the present invention, through further optimizing the design of the specific structure of the concrete-filled steel tube, it includes a steel tube, centrifugally formed concrete, and core concrete; wherein, the steel tube and the centrifugally formed concrete are prefabricated in a factory to form a precast hollow ultra-high-strength concrete-filled steel tube member. Subsequently, core concrete is poured on-site to form an ultra-high-strength concrete-filled steel tube composite column member, thereby improving the material performance of the core concrete and reducing the cross-sectional size and steel consumption.

[0024] (4) For the combined special-shaped column frame-confined concrete shear wall structure of the present invention, for the vertical connection of the concrete-filled steel tubes, by arranging ring ribs and connecting steel bars inside the steel tubes, it can be prefabricated in a factory; compared with the traditional connection nodes, on-site welding operations are completely avoided, improving the assembly efficiency; at the same time, after pouring and curing are completed, when the concrete-filled steel tube is subjected to tensile force, the ring ribs play an anchoring role on the connecting steel bars, thereby ensuring the connection strength at the connection node.

[0025] (5) A combined special-shaped column frame-constrained concrete shear wall structure of the present invention. End plates are provided at the ends of the connecting steel bars. Through the setting of these end plates, on the one hand, the anchoring force of the connecting steel bars can be improved, and on the other hand, the connecting steel bars can be positioned to ensure their perpendicularity. In addition, with the combined action of the erection steel bars and the supporting steel bars, the stability of the connecting steel bars is increased, and the displacement of the connecting steel bars caused by the scouring of the concrete during concrete pouring can be effectively prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of a combined special-shaped column frame-constrained concrete shear wall structure of the present invention;

[0027] Figure 2 is a schematic diagram of the internal structure of the wall in the present invention;

[0028] Figure 3 is a schematic diagram of the structure of an L-shaped shear wall in the present invention;

[0029] Figure 4 is an implementation manner of a horizontal connection node in the present invention;

[0030] Figure 5 is Figure 4 an enlarged view of the structure at the horizontal connection node in

[0031] Figure 6 is another implementation manner of a horizontal connection node in the present invention;

[0032] Figure 7 is Figure 6 an enlarged view of the structure at the horizontal connection node in

[0033] Figure 8 is a schematic diagram of the formation of a cross-section of a concrete-filled steel tube column in the present invention;

[0034] Figure 9 is a schematic diagram of the structure at the vertical connection node in the present invention;

[0035] Figure 10 is Figure 9 a sectional view taken along line A-A in

[0036] Figure 11 is Figure 9 a sectional view taken along line B-B in

[0037] Figure 12 is a force mechanism diagram at the vertical connection node in the present invention.

[0038] In the figures: 1. Wall; 2. Concrete-filled steel tube column; 21. Steel tube; 22. Centrifugally formed concrete; 23. Core concrete; 3. First connecting steel plate; 4. π-shaped steel; 5. Connecting stirrup.

[0039] 6. Horizontal connection node; 61. L-shaped steel; 62. Elastic cushion block; 63. Second connection steel plate; 64. Third connection steel plate; 65. Steel bar skeleton;

[0040] 7. Vertical connection node; 71. Ring rib; 72. Connecting steel bar; 73. End plate; 731. Long end plate; 732. Short end plate; 74. Erection steel bar. Specific embodiments

[0041] The present invention will be further described below in conjunction with specific embodiments.

[0042] Embodiment 1

[0043] As Figure 1 shown, a combined special-shaped column frame-confined concrete shear wall structure in this embodiment includes a wall body 1 and distribution steel bars arranged in the wall body 1. One end of the wall body 1 is provided with a concrete-filled steel tube column 2, and the other end is provided with a π-shaped steel 4. The concrete-filled steel tube column 2 and the π-shaped steel 4 are connected by connecting stirrups 5.

[0044] Specifically, as Figure 2 shown, two first connection steel plates 3 are provided on the concrete-filled steel tube column 2, and the two first connection steel plates 3 respectively correspond to the two flanges of the π-shaped steel 4, and the first connection steel plates 3 and the flanges of the π-shaped steel 4 are provided with through holes for the connecting stirrups 5 to pass through.

[0045] A combined special-shaped column frame-confined concrete shear wall structure in this embodiment forms a π-O special-shaped column frame-confined concrete shear wall by arranging a concrete-filled steel tube column 2 and a π-shaped steel 4 at both ends of the wall body, which can be used as a confined edge member to enhance the performance of the wall body. And a PBL shear key is formed by connecting the two with connecting stirrups 5, so that the two can work together, which can further improve the seismic performance of the wall body, and thus is applicable to high-rise buildings. At the same time, this connection method can avoid the setting of the web, save the amount of steel used, and can also increase the section moment of inertia and the flexural stiffness by adjusting the distance between the concrete-filled steel tube column 2 and the π-shaped steel 4, so that the overall structure can effectively control the deformation in the normal use stage. Under the action of rare earthquakes, the reinforced concrete wall body can effectively limit the out-of-plane buckling of the steel, enable it to fully exert its energy dissipation capacity, and can also achieve the performance coordination between the shear wall part and the frame part. In addition, by hiding the concrete-filled steel tube column 2 and the π-shaped steel 4 in the wall body, the column body is not exposed and occupies a small space, which can increase the indoor use space and enhance the flexibility of the household layout.

[0046] It should be noted that the shear wall structure in this embodiment can adopt different cross-sectional forms according to actual needs. For example, an L-shaped shear wall structure (as Figure 3 shown).

[0047] Example 2

[0048] Based on Example 1, this example provides a horizontal connection node 6, which is an expansion of the wall 1 in the horizontal direction based on the characteristics of the π-shaped steel 4.

[0049] Specifically, referring to Figure 4 、 Figure 5 As shown, the horizontal connection node 6 includes two L-shaped steels 61 arranged in central symmetry. One end of each L-shaped steel 61 is welded to its respective π-shaped steel 4, and the other end is a free end. The free ends of the two L-shaped steels 61 are misaligned and overlapped, and an elastic cushion block 62 is provided at the overlapping part. Preferably, the elastic cushion block 62 is a rubber block.

[0050] For a composite special-shaped column frame-confined concrete shear wall structure in this example, during the fabrication of the shear wall, the L-shaped steel 61 is welded to the π-shaped steel 4 at the end of the shear wall, and then the two L-shaped steels 61 are spliced, and a rubber block is provided at the splicing part to enable the shear wall connection node to have sufficient energy dissipation capacity under large earthquakes. Finally, a steel bar skeleton 65 is arranged in the joint area and concrete is poured, and the grade of the post-cast concrete is not lower than that of the shear wall itself, further enhancing the joint performance. The connection method in this example has clear force, simple connection, convenient on-site construction, and saves construction period.

[0051] Example 3

[0052] This example is another implementation manner of the horizontal connection node 6.

[0053] Referring to Figure 5 、 Figure 6 As shown, the horizontal connection node 6 includes a second connection steel plate 63 arranged on the π-shaped steel 4 of one side wall 1, and a third connection steel plate 64 arranged on the π-shaped steel 4 of the other side wall 1. The second connection steel plate 63 and the third connection steel plate 64 are misaligned and overlapped, and are connected by bolts, and post-cast concrete is used.

[0054] Specifically in this example, both the second connection steel plate 63 and the third connection steel plate 64 are "one-shaped" steel plates. Among them, one second connection steel plate 63 is provided, and two third connection steel plates 64 are provided; and the free end of the second connection steel plate 63 extends into the gap between the two third connection steel plates 64.

[0055] A combined special-shaped column frame-confined concrete shear wall structure according to this embodiment is based on the connection method between the π-shaped steel 4 and the bolts. When fabricating the shear wall, two "I-shaped" steel plates are welded to the π-shaped steel 4 at the end of the shear wall, and one "I-shaped" steel plate is welded to the π-shaped steel 4 at the end of another shear wall, and the "I-shaped" steel plates are connected by bolts; subsequently, a steel bar cage 65 is arranged in this joint area and concrete is cast later.

[0056] Of course, screw holes for the bolts to pass through need to be opened at the corresponding positions of the "I-shaped" steel plates. The spacing of these screw holes should not be too small (not less than 3d, where d is the nominal diameter of the bolt) so that the shear bearing capacity of each bolt can be fully exerted; and the spacing of the screw holes should not be too large (not more than 10d, where d is the nominal diameter of the bolt) to ensure that the joint area has sufficient load-bearing and energy-dissipating capacities.

[0057] Embodiment 4

[0058] A combined special-shaped column frame-confined concrete shear wall structure according to this embodiment further optimizes the specific structure of the concrete-filled steel tube column 2 on the basis of the above embodiment, and provides a new cross-section formation.

[0059] As Figure 8 shown, the concrete-filled steel tube column 2 includes a steel tube 21, centrifugally formed concrete 22 arranged inside the steel tube 21, and core concrete 23 arranged inside the centrifugally formed concrete 22; wherein, the centrifugally formed concrete 22 is prefabricated in a factory, and the core concrete 23 is formed by on-site casting.

[0060] Specifically in this embodiment, the strength of the core concrete 23 is C30 - C60, preferably C60 concrete; the centrifugally formed concrete 22 is ultra-high-strength concrete. To ensure production quality, combined with the conventional production processes of ultra-high-strength concrete components by existing relevant manufacturers, it is recommended that the strength of the ultra-high-strength concrete used does not exceed C120. The adopted outer steel tube and ultra-high-strength concrete will provide a strong confinement effect on the cast-in-place concrete to ensure the ductility of the component.

[0061] A combined special-shaped column frame-confined concrete shear wall structure according to this embodiment forms a precast hollow ultra-high-strength concrete-filled steel tube component through the steel tube 21 and the centrifugally formed concrete 22, and this component can be prefabricated in a factory. Subsequently, the core concrete 23 is cast on-site to form an ultra-high-strength concrete-filled steel tube composite column component, thereby improving the material properties of the core concrete, reducing the cross-section size and steel consumption.

[0062] Embodiment 5

[0063] On the basis of the above embodiment, this embodiment provides a vertical connection joint 7 to complete the vertical splicing of the concrete-filled steel tube column 2.

[0064] As shown Figure 9 、 Figure 10 in the figure, the vertical connection node 7 includes a ring rib 71 and connecting steel bars 72; among them, the ring rib 71 is arranged on the inner wall of the steel pipe 21 and near the end of the steel pipe 21; a plurality of the connecting steel bars 72 are distributed annularly, one end of which is located inside the steel pipe 21 and the other end extends outside the steel pipe 21; after the pouring is completed, the ring rib 71 plays an anchoring role on the connecting steel bars 72.

[0065] Among them, the ring rib 71 is preferably a steel pipe rib, and it can be selected in a variety of cross-sectional forms, such as T-shaped steel, channel steel, solid round / rectangular steel bars, etc.

[0066] Of course, a space for installing the vertical connection node 7 needs to be reserved inside the steel pipe 21. That is to say, the centrifugally formed concrete 22 does not extend all the way to the end of the steel pipe 21, but there is a certain distance between it and the end of the steel pipe 21, and this reserved section is the vertical connection node area.

[0067] In the combined special-shaped column border-constrained concrete shear wall structure of this embodiment, the precast hollow ultra-high-strength concrete-filled steel tube members are partially connected by arranging connecting steel bars 72 inside and pouring core concrete 23. The key to realizing tensile equal-strength connection lies in whether the steel pipe 21 has sufficient anchoring effect on the internal connecting steel bars 72.

[0068] According to the previous refined finite element analysis, by setting a ring rib 71 at the inner end of the steel pipe 21 to transfer the anchoring force, the shear force between the two can be effectively transferred, thereby enhancing the anchoring force on the connecting steel bars 72. The specific force mechanism can be referred to Figure 12 .

[0069] To further improve the anchoring effect, the steel pipe 21 is preferably made of a material with a surface friction coefficient of not less than 0.5, for example, a threaded steel pipe. For cold-formed / thermally formed straight-seam welded steel pipes, it is also possible to choose to sandblast (shot blast) the plate before the bending forming process to increase the friction coefficient, so as to achieve the optimal anchoring effect.

[0070] To reduce the influence of the welding precision of the ring rib 71 in the factory on the on-site construction and leave a certain welding space, it is recommended to arrange the ring rib 71 about 30 mm away from the end of the steel pipe 21. At the same time, in order to minimize the volume of the concrete above the ring rib and its damage (tensile damage is likely to occur under seismic loads, while the concrete below the ring rib is mainly under pressure, and the performance of the concrete material can be effectively exerted). According to the previous theoretical and experimental research of the inventor, the distance between the position where the ring rib 71 is set and the end of the steel pipe 21 needs to be less than 0.3l R . Among them, l R is the steel bar anchoring length, and the anchoring length here refers to the depth of the connecting steel bar 72 located inside a single steel pipe 21.

[0071] In addition, the distance between the connecting steel bar 72 and the ring rib 71 should not be greater than the difference between the steel bar anchorage length and the depth of the ring rib 71. The reason is that the transfer of the anchoring force mainly relies on the shear force between concrete units and the pressure between upper and lower units. The maximum resultant direction of the above two is 45 degrees. At this time, the distance between the connecting steel bar 72 and the ring rib 71 is exactly equal to the difference between the steel bar anchorage length and the depth of the ring rib 71. When the distance between the connecting steel bar 72 and the ring rib 71 exceeds this value, the anchoring force cannot be effectively transferred, and local shear failure will occur in the internal concrete of the joint.

[0072] Example 6

[0073] In order to facilitate the positioning of the connecting steel bar 72 and ensure that the connecting steel bar 72 can have sufficient stability when pouring the core concrete 23. On the basis of Example 5, the specific structure of the vertical connecting joint 7 is further improved in this example.

[0074] Reference Figure 9 、 Figure 10 As shown, an end plate 73 is provided at the end of the connecting steel bar 72. During assembly, the end of the end plate 73 abuts against the inner wall of the steel pipe 21 to position the connecting steel bar 72 and ensure its verticality.

[0075] An annular erection steel bar 74 is further provided inside the connecting steel bar 72, and multiple groups of the erection steel bars 74 are arranged along the length direction of the connecting steel bar 72. That is, through the arrangement of the erection steel bar 74, multiple connecting steel bars 72 are combined into a whole, which can be integrally prefabricated in the factory, thereby further saving the construction time on site.

[0076] Since multiple connecting steel bars 72 are connected into a whole ring by the erection steel bar 74, it is not necessary to position each connecting steel bar 72 separately, but only to position the whole connecting steel bar ring as a whole. That is to say, as long as the ends of some end plates 73 can abut against the inner wall of the steel pipe 21, the verticality of the whole connecting steel bar 72 can be ensured.

[0077] Specifically in this example, as shown in Figure 11 the end plate 73 includes a long end plate 731 and a short end plate 732, and the long end plate 731 and the short end plate 732 are arranged alternately. Through the arrangement of the long end plate 731 and the short end plate 732, not only the anchoring force of the connecting steel bar 72 can be improved, but also the connecting steel bar 72 can be positioned to ensure its verticality.

[0078] In addition, to prevent the connecting steel bars 72 from moving downward due to the impact brought by the concrete during the pouring process. In this embodiment, a support bar (not shown in the figure) is provided on the outer side of the connecting steel bar 72, and the connecting steel bar 72 is hung on the ring rib 71 through this support bar, so that the connecting steel bar 72 can be effectively supported.

[0079] In the combined special-shaped column boundary-reinforced concrete shear wall structure of this embodiment, through the common limiting of the connecting steel bar 72 by the end plate 73, the erection steel bars 74 and the support bar, not only the perpendicularity of the connecting steel bar 72 is ensured, but also the stability of the connecting steel bar 72 is increased, which can effectively prevent the displacement of the connecting steel bar due to the scouring of the concrete during the pouring of the concrete, thus affecting the final connection effect.

[0080] In addition, according to the model analysis results, when the diameter of the connecting steel bar exceeds 22 mm, an obvious "pinching" phenomenon will appear in the hysteretic curve, significantly reducing the energy dissipation capacity of the joint. Therefore, it is recommended that the diameter of the steel bar does not exceed 22 mm. The reason for this "pinching" phenomenon is that on the premise of equal reinforcement ratio, too large a steel bar size will lead to a reduction in the number of steel bars, a significant increase in the bond-slip effect between the steel bar and the concrete around a single steel bar, and a significant increase in the bond stress, making the concrete around the steel bar prone to damage and reducing the overall energy dissipation capacity of the joint, so the hysteretic curve shows "pinching".

[0081] Embodiment 7

[0082] On the basis of the above embodiment, the specific components and process of the centrifugally formed concrete 22 are further optimized and designed.

[0083] Specifically, the centrifugally formed concrete 22 can adopt the following mix ratio: water 200 - 250 kg / m 3 、cement 800 - 1000 kg / m 3 、natural sand / manufactured sand 750 - 1125 kg / m 3 、silica fume 135 - 170 kg / m 3 、the dosage of the high-performance polycarboxylate water reducer is 0.5% - 1% of the cement dosage, and the dosage of the steel fiber is 1% (0.01 cubic meters of steel fiber is contained in 1 cubic meter of concrete). Considering that the price of natural sand / manufactured sand is relatively high in some areas, part of the natural sand can also be replaced by natural stone, and the proportion of the quality of natural stone in the total aggregate quality (the sum of the quality of fine and coarse aggregates) does not exceed 20%.

[0084] The specific preparation process is as follows: 1) First, put all the aggregates, silica fume, and steel fibers into the mixing device and mix for 10 minutes to make the aggregates, silica fume, and steel fibers evenly distributed; 2) Slowly pour water during the mixing process. The amount of water poured is 1 / 2 of the total water volume. The water selected is urban domestic water, and the water temperature is recommended to be not lower than 15 °C to ensure the effective development of concrete strength. For mixing plants with conditions, the water temperature can be increased to 30 °C. This water temperature can ensure that the cube compressive strength of the concrete reaches 50 MPa within 3 days and ensure the development of later strength; 3) The water addition and mixing process needs to last for 10 minutes to ensure the full reaction of silica fume; 4) Subsequently, add cement into the mixing device, and then incorporate all the remaining water, and mix for 5 minutes; 5) Finally, add a water reducer. It is recommended to select a high-performance polycarboxylate liquid water reducer, which can improve the fluidity of the concrete and facilitate pumping.

[0085] The characteristics and advantages of the above preparation method mainly include two points: 1) In traditional steel fiber ultra-high-strength concrete, the steel fiber content is usually relatively high (volume content greater than 2%). At this time, the material preparation cost is relatively high and it cannot be well used in practical engineering. However, by improving the preparation method, increasing the mixing time and the order of admixtures, the mechanical properties of the concrete will not change significantly when the steel fiber content is reduced. According to the previous experimental research, when the steel fiber content is less than 0.5%, the improvement of the mechanical properties of the concrete is very limited, while when it is about 1%, it shows obvious beneficial effects. Compared with not adding steel fibers, the deformation ability of the material can be increased by more than 50%, ensuring the seismic performance of ultra-high-strength concrete components when applied in shear wall structures; 2) The order of adding materials is different from the traditional method of adding all admixtures at one time. The preparation process of first adding aggregates and steel fibers, then adding part of warm water, and finally adding the remaining water, silica fume, and cement is selected. This process first mixes the steel fibers with the aggregates. When there is no water involved in the mixing, they can be evenly distributed by continuous stirring. Subsequently, water is added, and the relative positions of the steel fibers are fixed through the adhesion ability of water. Finally, the remaining admixtures are added for full reaction. It ensures the distribution of fibers in the steel fiber ultra-high-strength concrete and reduces the fiber content under the same performance control conditions.

[0086] Example 8

[0087] Due to the restraint effect of the steel pipe 21, recycled concrete can be used to replace ordinary concrete materials for the core concrete 23. The replacement rates of coarse and fine aggregates can reach 100%, thereby reducing the overall carbon emissions and improving the comprehensive recycling disposal capacity of urban construction waste. According to the inventor's previous research, the influence of incorporating recycled aggregates on the bearing capacity of concrete-filled steel tubes does not exceed 15%. Through reasonable design, the performance of recycled concrete composite special-shaped columns can be made equivalent to that of ordinary concrete on the basis of basically not increasing the cost.

[0088] Among them, the mix ratio of recycled concrete: water 180 - 200 kg / m3 , 360 - 600 kg / m of cement 3 , 1080 - 1240 kg / m of natural coarse aggregate 3 , 610 - 710 kg / m of natural fine aggregate 3 , The dosage of naphthalene-based water reducer is 0.5% - 1% of the cement dosage, that is, 2 - 6 kg / m 3 . In the above mix ratio, the recycled coarse and fine aggregates can be replaced by volume or mass. Combining with the self-density of the recycled aggregates and the required replacement rate, the mass of the corresponding natural aggregate components is converted into the mass of the recycled aggregate components.

[0089] In the above mix ratio, the recycled coarse aggregate is pretreated by the saturated surface dry method, and the recycled fine aggregate is treated by the pre-soaking method. The pre-soaking water volume (this water volume is the additional water volume and is not included in the water in the above mix ratio) is 0.5 - 1.0 times the difference between the saturated water absorption and the natural water content of the recycled fine aggregate. Using this method can make the reduction range of concrete performance controllable. At the same time, the slump of the fresh concrete is not less than 150 mm, ensuring its sufficient workability in actual projects. It should be noted that the recycled aggregates referred to in this embodiment are all green aggregates obtained by crushing and screening waste concrete. The aggregates obtained from the treatment of waste bricks, glass, and blocks do not fall within the scope involved in this embodiment.

[0090] In addition, considering that there are certain differences in the physical properties of the recycled coarse and fine aggregates and their large water absorption rates, which may affect the workability of the fresh concrete and the mechanical properties of the hardened concrete, the preparation method of recycled concrete can adopt the three-stage mixing method: 1) First, put the recycled fine aggregate, natural aggregate (if any), and half of the total water volume (the water volume in the mix ratio + the additional water volume) into the mixing device and stir for 5 minutes to make the recycled fine aggregate fully absorb water; 2) Then put the recycled coarse aggregate into the mixing pan and stir for 5 minutes to make it fully wet. At this time, add the cement. The active components in the cement will react with the water on the surface of the aggregate, and the hydration products generated will seal the pores on the surface of the aggregate, so that it will not exchange humidity with the free water inside the concrete during the setting and hardening process of the concrete; 3) Finally, add the remaining water and the water reducer. The amount of the water reducer can be adjusted as appropriate according to the replacement rate of the recycled aggregates. When the replacement rate of the recycled coarse and fine aggregates does not exceed 50%, the dosage of the water reducer can be 5% of the cement mass. When it exceeds 50%, it can be taken as 1% to ensure the pumpability of the concrete.

[0091] The biggest difference from the traditional proportioning is that with the above proportioning, the replacement rates of recycled coarse and fine aggregates can be simultaneously increased to 100%, with little impact on the material properties, thereby increasing the recycling rate of construction waste. Through a large number of previous tests, it is found that when using the above method, the workability of the material is good, the pores on the surface of the recycled coarse aggregate can be filled by the recycled fine aggregate and the hydration products of a small amount of unhydrated cement contained therein, the microstructure is dense after hardening, and the difference in compressive strength between the recycled concrete and the ordinary concrete does not exceed 10%.

[0092] In summary, for a combined special-shaped column frame-confined concrete shear wall structure of the present invention, by arranging concrete-filled steel tubes 2 and π-shaped steel 4 at both ends of the wall, and forming a PBL shear key through connecting stirrups 5 therebetween, a π-O special-shaped column frame-confined concrete shear wall is formed. It can not only improve the seismic performance of the wall, but also make the columns not exposed and occupy less space, increasing the indoor usable space and enhancing the flexibility of apartment layout. In addition, in the present invention, based on the π-O special-shaped column frame-confined concrete shear wall, a horizontal connection node 6 between walls and a vertical connection node between concrete-filled steel tubes 2 are proposed, which have good mechanical properties and integrity while ensuring a high assembly rate of the node system. Finally, a new structural system with excellent seismic performance, low steel consumption, good integrity, high assembly rate, large usable space, and flexible structural layout is proposed to promote the high-quality development of the construction industry.

[0093] The above has schematically described the present invention and its implementation manners, and this description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural manners and embodiments without creative work without departing from the spirit of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A combined special-shaped column frame-confined concrete shear wall structure, comprising a wall body (1), characterized in that: One end of the wall body (1) is provided with a concrete-filled steel tube column (2), and a first connecting steel plate (3) is arranged on the concrete-filled steel tube column (2), and the other end is provided with a π-shaped steel (4); wherein, two first connecting steel plates (3) are provided, which respectively correspond to the two flanges of the π-shaped steel (4), and the first connecting steel plate (3) is connected with the flange of the π-shaped steel (4) through connecting stirrups (5). The wall bodies (1) are connected horizontally through a horizontal connection node (6), and the horizontal connection node (6) includes an L-shaped steel (61) arranged on the π-shaped steel (4), and the two L-shaped steels (61) on the connected wall bodies (1) are arranged in central symmetry, and an elastic cushion block (62) is arranged at the connection of the two L-shaped steels (61), and then concrete is cast later.

2. A combined special-shaped column boundary-reinforced concrete shear wall structure according to claim 1, characterized in that: The concrete-filled steel tube column (2) includes a steel tube (21), centrifugally formed concrete (22) arranged in the steel tube (21), and core concrete (23) arranged in the centrifugally formed concrete (22); wherein, the centrifugally formed concrete (22) is prefabricated in a factory, and the core concrete (23) is formed by on-site casting.

3. A combined special-shaped column boundary-reinforced concrete shear wall structure according to claim 2, characterized in that: The strength of the core concrete (23) is C30 - C60, and the strength of the centrifugally formed concrete (22) does not exceed C120.

4. A composite special-shaped column boundary confined concrete shear wall structure according to claim 2, characterized in that: The concrete-filled steel tube columns (2) are connected vertically through a vertical connection node (7), and the vertical connection node (7) includes a ring rib (71) and connecting steel bars (72); wherein, the ring rib (71) is arranged on the inner wall of the steel tube (21) and close to the end of the steel tube (21); a plurality of the connecting steel bars (72) are distributed annularly, one end of which is located inside the steel tube (21), and the other end extends outside the steel tube (21); after the casting is completed, the ring rib (71) plays an anchoring role on the connecting steel bars (72).

5. A combined special-shaped column frame-confined concrete shear wall structure according to claim 4, characterized in that: An end plate (73) is arranged at the end of the connecting steel bar (72), and the end plate (73) includes a long end plate (731) and a short end plate (732), wherein, the end of the long end plate (731) abuts against the inner wall of the steel tube (21).

6. A combined special-shaped column boundary-confined concrete shear wall structure according to claim 5, characterized in that: An annular erection steel bar (74) is arranged in the space surrounded by the plurality of connecting steel bars (72), and a plurality of groups of the erection steel bars (74) are arranged along the length direction of the connecting steel bars (72).

7. A combined special-shaped column boundary-constrained concrete shear wall structure according to claim 6, characterized in that: Supporting steel bars are arranged on the outer side of the connecting steel bars (72), and the connecting steel bars (72) are positioned on the ring rib (71) through the supporting steel bars.

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