A self-centering prefabricated UHPC frame beam-column joint and its construction method

Abstract

The present invention relates to the field of prefabricated building structures in civil engineering, and in particular to a self-resetting prefabricated UHPC frame beam-column node and a construction method thereof, comprising a prefabricated frame beam component, a prefabricated frame column component, ultra-high performance concrete, and a self-resetting friction energy absorber, wherein the prefabricated frame beam component and the prefabricated frame column component are connected by post-cast ultra-high performance concrete at the node. The high-strength steel bar section in the prefabricated frame beam component is arranged near the node and extends into the frame column, so as to improve the cross-sectional bearing capacity and reduce the damage of the frame beam; the non-bonded section of ordinary steel bars can release the interaction between the steel bars and concrete in the section, and concentrate the damage in the designated area of ​​the frame beam; the self-resetting friction energy absorber is used to share the energy dissipation of the connection node, and provides a certain self-resetting ability to control the residual deformation of the structure.

Description

Technical Field

[0001] The present invention relates to the field of civil engineering assembled building structures, and in particular to a self-resetting assembled UHPC frame beam-column node and a construction method thereof. Background Art

[0002] The key to prefabricated concrete frame structures lies in the reliable connection between prefabricated components. The connection nodes of prefabricated frames are important connection points and force transmission nodes between frame beams and frame columns. Once damaged, they will affect the stability of the overall structure. From the perspective of engineering practice, existing connection nodes have defects such as complex structure and force, poor integrity, and difficult to ensure construction quality. It is difficult to ensure that they are completely equivalent to cast-in-place frame structures, and the connection nodes are weak links in earthquake resistance. Under the action of rare or extremely rare earthquakes, damage and failure of the connection nodes may cause the overall collapse of the structure. Summary of the invention

[0003] The present invention provides a self-resetting assembled UHPC frame beam-column node and a construction method thereof, which can solve the technical problem that the existing assembled beam-column node connection is a weak link in earthquake resistance and is easily damaged and fails first.

[0004] The technical implementation scheme of the present invention is: a self-resetting assembled UHPC frame beam-column node, including a prefabricated frame beam component, a prefabricated frame column component, ultra-high performance concrete, a self-resetting friction energy absorber, a pad 1, a pad 2, a connector and a node plate, the prefabricated frame beam component and the prefabricated frame column component are connected by post-cast ultra-high performance concrete at the node, the prefabricated frame beam component is connected with a pad 1, the prefabricated frame column component is connected with a pad 2, the pad 1 and the pad 2 are both connected with a node plate, a self-resetting friction energy absorber is arranged between the two node plates, the longitudinal stress-bearing steel bars of the prefabricated frame beam component and the prefabricated frame column component are connected by a connector, and the longitudinal stress-bearing steel bars in the prefabricated frame beam component include three sections: a high-strength steel bar section, a non-bonded section of ordinary steel bars and a bonded section of ordinary steel bars.

[0005] Preferably, the connector includes a locking ring and a rubber connecting block, each connector is provided with two locking rings and two rubber connecting blocks, the rubber connecting block can be screwed into the high-strength steel bar section, the ordinary steel bar non-bonded section and the ordinary steel bar bonded section through threads, and the two locking rings are sleeved on two adjacent rubber connecting blocks.

[0006] Preferably, one side of the rubber connecting block is conical, and the conical side is installed outward, and the internal structure of the locking collar is consistent with the structure of the rubber connecting block.

[0007] Preferably, the steel bar strength grade used in the high-strength steel bar section is higher than that in the ordinary steel bar non-bonded section and the ordinary steel bar bonded section. The high-strength steel bar section is arranged near the node and extends into the prefabricated frame column component. The high-strength steel bar length ratio is used to control the design parameters. The high-strength steel bar length ratio is the high-strength steel bar length / frame column width, and the high-strength steel bar length ratio should be 1.2-1.4.

[0008] Preferably, the non-bonded section of ordinary steel bars adopts a dimensionless parameter - non-bonded section ratio to control the design parameters. The non-bonded section ratio is the non-bonded section length / total length of ordinary steel bars. The non-bonded section ratio should be 0.2-0.4.

[0009] Preferably, the self-resetting friction energy absorber includes a self-resetting device and a rotational friction damper, the self-resetting device and the rotational friction damper are arranged between the two node plates, and the rotational friction damper is connected to the node plate in a hinged connection.

[0010] Preferably, the rotational friction damper comprises a connecting rod and a friction damper, the two node plates are hingedly connected with connecting rods on both sides, the connecting rods on the two node plates are hinged to each other and the friction damper is arranged at the hinge.

[0011] Preferably, the self-resetting friction energy absorber adopts a dimensionless parameter - the energy absorber yield strength ratio to control the design parameters. The energy absorber yield strength ratio is the yield bending moment of the self-resetting friction energy absorber / the yield bending moment of the frame beam cross section. The energy absorber yield strength ratio reflects the relationship between the design yield strength of the self-resetting friction energy absorber and the yield strength of the frame beam. The energy absorber yield strength ratio is 0.3-0.6.

[0012] A construction method for a low-damage self-resetting assembled ultra-high performance concrete frame beam-column node comprises the following steps:

[0013] S1: manufacturing a prefabricated frame beam component, configuring the steel bars required for the prefabricated frame beam component, wherein the longitudinal force-bearing steel bars specifically include three sections of "high-strength steel bar section + ordinary steel bar non-bonded section + ordinary steel bar bonded section", each section is connected by a connector, a pad for fixing the connecting plate is reserved at an appropriate position of the beam, and concrete is poured as a whole to form the prefabricated frame beam component;

[0014] S2: manufacturing a prefabricated frame column component, configuring the steel bars required for the prefabricated frame column component, reserving a second pad for fixing the connecting plate at an appropriate position of the column, and integrally pouring concrete to form the prefabricated frame column component;

[0015] S3: The longitudinal stress-bearing reinforcements of the upper and lower precast frame column components are connected by connectors, and the beam-column joint area is cast with ultra-high performance concrete;

[0016] S4: The node plate is welded to the pad 1 and the pad 2, and finally the self-resetting friction absorber is installed, which specifically includes 1 set of self-resetting devices and 2 sets of rotational friction dampers. Each component is connected to the node plate by a hinge.

[0017] The beneficial effects of the present invention are as follows: 1. The high-strength steel bar section is arranged near the node and extends into the frame column, thereby improving the cross-sectional bearing capacity and reducing the damage of the frame beam; the non-bonded section of ordinary steel bars can release the interaction between the steel bars and concrete in this section, and concentrate the damage in the specified area of ​​the frame beam; the displacement amplification effect between the beams and columns in the non-bonded section is fully utilized, and the self-resetting device and the rotational friction damper are used to share the energy dissipation of the connection node, further reducing the degree of damage to the component, and providing a certain self-resetting ability to control the residual deformation of the structure.

[0018] 2. The mechanical properties of the beam-column nodes formed by connecting prefabricated components with ultra-high performance concrete are much better than those of the beam-column nodes formed by connecting with ordinary concrete, which can further improve the bending resistance of the nodes and reduce the degree of damage to the nodes under earthquake action.

[0019] 3. The low-damage self-resetting prefabricated ultra-high performance concrete frame beam-column node formed based on the design concept of plastic damage transfer can keep the damage away from the core area of ​​the node, realize the seismic working mechanism of energy absorption device deformation and plastic hinge formation at the beam end, avoid premature damage and destruction at the node, and have a certain self-resetting characteristic, realizing the design requirements of "strong node, weak component", and achieving the effect of improving the seismic performance of the prefabricated concrete frame structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0021] Figure 2 It is a partial three-dimensional structural schematic diagram of the present invention.

[0022] Figure 3 It is a cross-sectional view of the present invention.

[0023] Figure 4 It is a schematic diagram of the self-resetting friction energy absorber of the present invention.

[0024] Figure 5 It is a cross-sectional view of the ultra-high performance concrete of the present invention.

[0025] Figure 6 It is a cross-sectional view of the rear side of the prefabricated frame beam component of the present invention.

[0026] Figure 7 It is a cross-sectional view of the front side of the prefabricated frame beam component of the present invention.

[0027] Figure 8It is a first schematic diagram of the high-strength steel bar section, the ordinary steel bar non-bonded section, the ordinary steel bar bonded section and the connector of the present invention.

[0028] Fig. 9 This is a second schematic diagram of the high-strength steel bar section, the ordinary steel bar non-bonded section, the ordinary steel bar bonded section and the connector of the present invention.

[0029] Fig.10 It is a cross-sectional view of the connector of the present invention.

[0030] Fig.11 For the present invention Fig.10 Enlarged view of part A in .

[0031] In the accompanying drawings: 1-prefabricated frame beam member, 2-prefabricated frame column member, 3-ultra-high performance concrete, 4-self-resetting friction energy absorber, 41-self-resetting device, 42-rotational friction damper, 421-connecting rod, 422-friction damper, 5-connector, 51-locking ring, 52-rubber connecting block, 6-node plate, 11-high-strength steel bar section, 12-ordinary steel bar non-bonded section, 13-ordinary steel bar bonded section, 14-pad one, 21-pad two. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0033] Example 1

[0034] A self-resetting assembled UHPC frame beam-column node, such as Figure 1-11 As shown, it includes a prefabricated frame beam component 1, a prefabricated frame column component 2, an ultra-high performance concrete 3 (UHPC), a self-resetting friction energy absorber 4, a pad 14, a pad 21, a connector 5 and a node plate 6. The prefabricated frame beam component 1 and the prefabricated frame column component 2 are connected by post-casting ultra-high performance concrete 3 at the node, the left side of the front side of the prefabricated frame beam component 1 is connected to the pad 14, the right side of the prefabricated frame column component 2 is connected to the pad 21, the pad 14 and the pad 21 are both connected to the node plate, and the self-resetting friction energy absorber 4 is arranged between the two node plates. The longitudinal stress-bearing steel bars of the prefabricated frame beam component 1 and the prefabricated frame column component 2 are connected by a connector 5. The longitudinal stress-bearing steel bars in the prefabricated frame beam component 1 include three sections: a high-strength steel bar section 11, a common steel bar non-bonded section 12 and a common steel bar bonded section 13, so as to achieve a damage control effect.

[0035] like Figure 8-Figure 11As shown, the connector 5 includes a locking ring 51 and a rubber connecting block 52. Each connector 5 is provided with two locking rings 51 and two rubber connecting blocks 52. The rubber connecting block 52 can be screwed into the high-strength steel bar section 11, the ordinary steel bar non-bonded section 12 and the ordinary steel bar bonded section 13 through threads. The two locking rings 51 can be mounted on two adjacent rubber connecting blocks 52 and locked with bolts to fix the rubber connecting blocks 52. The two adjacent rubber connecting blocks 52 are slidably connected to each other with a gap between them to allow the high-strength steel bar section 11, the ordinary steel bar non-bonded section 12 and the ordinary steel bar bonded section 13 to return to their original positions after being subjected to tension.

[0036] like Fig.10 As shown, one side of the rubber connecting block 52 is conical. When the rubber connecting block 52 is installed, the conical side is installed outward. The internal structure of the locking collar 51 is consistent with the structure of the rubber connecting block 52. When the high-strength steel bar section 11, the ordinary steel bar non-bonded section 12 and the ordinary steel bar bonded section 13 are subjected to tension, the rubber connecting block 52 is pulled to move. The conical setting makes the rubber connecting block 52 and the locking collar 51 tightened. The greater the tension, the tighter they are pulled.

[0037] like Figure 2 , Figure 3 and Figure 5 As shown, the steel bar strength grade used in the high-strength steel bar section 11 must be higher than that of the ordinary steel bar non-bonded section 12 and the ordinary steel bar bonded section 13. The high-strength steel bar section 11 is arranged near the node and extends into the prefabricated frame column component 2. The high-strength steel bar length ratio (i.e., high-strength steel bar length / frame column width) is used to control the design parameters, and the high-strength steel bar length ratio is 1.2-1.4.

[0038] like Figure 2 , Figure 3 and Figure 6 As shown, the non-bonded section 12 of the ordinary steel bar adopts a dimensionless parameter - non-bonded section ratio (i.e., non-bonded section length / total length of ordinary steel bar) to control the design parameters. The non-bonded section ratio reflects the degree of release of the steel bar-concrete interaction, and the non-bonded section ratio is 0.2-0.4.

[0039] like Figure 1 and Figure 4As shown, the self-resetting friction energy absorber 4 includes a self-resetting device 41 and a rotational friction damper 42. A set of self-resetting devices 41 and two sets of rotational friction dampers 42 are arranged between two node plates 6. The rotational friction damper 42 is connected to the node plate 6 in a hinged manner. When the frame beam-column node rotates relatively, the rotational friction damper 42 undergoes angular deformation and energy consumption, and the self-resetting device 41 undergoes axial deformation and has self-resetting capability. The self-resetting friction energy absorber 4 can dissipate part of the earthquake input energy and provide a certain self-resetting capability, significantly improving the seismic performance of the assembled concrete frame structure.

[0040] like Figure 4 As shown, the rotational friction damper 42 includes two connecting rods 421 and a friction damper 422. The two node plates 6 are hingedly connected with the connecting rods 421 on both sides. The connecting rods 421 on the two node plates 6 are hingedly connected to each other and the friction damper 422 is arranged at the hinge.

[0041] The self-resetting friction energy absorber 4 uses a dimensionless parameter - the energy absorber yield strength ratio (i.e., the yield bending moment of the self-resetting friction energy absorber 4 / the yield bending moment of the frame beam cross section) to control the design parameters. The energy absorber yield strength ratio reflects the relationship between the design yield strength of the self-resetting friction energy absorber 4 and the yield strength of the frame beam. The energy absorber yield strength ratio is 0.3-0.6.

[0042] This embodiment also provides a construction method for a self-resetting assembled UHPC frame beam-column node, comprising the following steps:

[0043] S1: manufacturing a prefabricated frame beam component 1, configuring the steel bars required for the prefabricated frame beam component 1, wherein the longitudinal force-bearing steel bars specifically include three sections of "high-strength steel bar section 11 + ordinary steel bar non-bonded section 12 + ordinary steel bar bonded section 13", each section is connected by a connector 5, a pad 14 for fixing the connecting plate is reserved at an appropriate position of the beam, and concrete is poured as a whole to form the prefabricated frame beam component 1;

[0044] S2: manufacturing a prefabricated frame column component 2, configuring the steel bars required for the prefabricated frame column component 2, reserving a pad 21 for fixing the connecting plate at an appropriate position of the column, and integrally pouring concrete to form the prefabricated frame column component 2;

[0045] S3: The longitudinal force-bearing steel bars of the upper and lower precast frame column components 2 are connected using connectors 5, and the beam-column node area is cast with ultra-high performance concrete 3;

[0046] S4: The node plate 6 is welded to the pad 1 14 and the pad 2 21 , and finally the self-resetting friction energy absorber 4 is installed, which specifically includes a set of self-resetting devices 41 and two sets of rotational friction dampers 42 , and each component is connected to the node plate 6 by hinged connection.

[0047] Although the present invention is described in detail with reference to the above embodiments, it is obvious to those skilled in the art through this disclosure that various changes or modifications may be made to the present invention without departing from the principle and spirit of the present invention defined by the claims. Therefore, the detailed description of the embodiments of the present disclosure is only used to explain, not to limit the present invention, but the scope of protection is limited by the content of the claims.

Claims

1. A self - resetting prefabricated UHPC frame beam - column joint, which is characterized in that: It includes a prefabricated frame beam member (1), a prefabricated frame column member (2), ultra - high - performance concrete (3), a self - resetting friction energy dissipator (4), a first backing plate (14), a second backing plate (21), a connector (5) and a gusset plate (6). The prefabricated frame beam member (1) and the prefabricated frame column member (2) are connected by post - casting ultra - high - performance concrete (3) at the joint. A first backing plate (14) is connected to the prefabricated frame beam member (1), a second backing plate (21) is connected to the prefabricated frame column member (2), and gusset plates (6) are connected to both the first backing plate (14) and the second backing plate (21). A self - resetting friction energy dissipator (4) is arranged between the two gusset plates. The longitudinal stressed steel bars of the prefabricated frame beam member (1) and the prefabricated frame column member (2) are connected by a connector (5). The longitudinal stressed steel bars in the prefabricated frame beam member (1) include a high - strength steel bar section (11), a non - bonded ordinary steel bar section (12) and a bonded ordinary steel bar section (13) in three - section form.

2. A self - resetting prefabricated UHPC frame beam - column joint as claimed in claim 1, which is characterized in that: The connector (5) includes a locking collar (51) and a rubber connecting block (52). Each connector (5) is provided with two locking collars (51) and two rubber connecting blocks (52). The rubber connecting block (52) can be screwed into the high - strength steel bar section (11), the non - bonded ordinary steel bar section (12) and the bonded ordinary steel bar section (13) through threads, and the two locking collars (51) are sleeved at the positions of two adjacent rubber connecting blocks (52).

3. A self - resetting prefabricated UHPC frame beam - column joint as claimed in claim 2, which is characterized in that: One side of the rubber connecting block (52) is tapered, and the tapered side is installed outward. The internal structure of the locking collar (51) is the same as that of the rubber connecting block (52).

4. A self - resetting prefabricated UHPC frame beam - column joint as claimed in claim 1, which is characterized in that: The strength grade of the steel bars used in the high - strength steel bar section (11) is higher than that of the non - bonded ordinary steel bar section (12) and the bonded ordinary steel bar section (13). The high - strength steel bar section (11) is arranged near the joint and extends into the prefabricated frame column member (2). The design parameters are controlled by the high - strength steel bar length ratio, and the high - strength steel bar length ratio is the high - strength steel bar length / column width. The high - strength steel bar length ratio should be 1.2 - 1.

4.

5. A self - resetting prefabricated UHPC frame beam - column joint as claimed in claim 1, which is characterized in that ordinary The design parameters of the non - bonded ordinary steel bar section (12) are controlled by a dimensionless parameter - the non - bonded section ratio. The non - bonded section ratio is the non - bonded section length / total length of ordinary steel bars, and the non - bonded section ratio should be 0.2 - 0.

4.

6. A self - resetting prefabricated UHPC frame beam - column joint as claimed in claim 1, which is characterized in that: The self - reset friction energy dissipator (4) includes a self - reset device (41) and a rotational friction damper (42). The self - reset device (41) and the rotational friction damper (42) are arranged between two gusset plates (6), and the rotational friction damper (42) is connected to the gusset plate (6) by hinged connection.

7. A self - reset prefabricated UHPC frame beam - column joint as claimed in claim 6, characterized in that: The rotational friction damper (42) includes a connecting rod (421) and a friction damper (422). Connecting rods (421) are hinged to both sides of the two gusset plates (6), and the connecting rods (421) on the two gusset plates (6) are hinged to each other and a friction damper (422) is arranged at the hinge.

8. A self - reset prefabricated UHPC frame beam - column joint as claimed in claim 7, characterized in that: The self - reset friction energy dissipator (4) uses a dimensionless parameter - the energy dissipator yield strength ratio to control the design parameters. The energy dissipator yield strength ratio is the yield moment of the self - reset friction energy dissipator / the yield moment of the cross - section of the frame beam. The energy dissipator yield strength ratio reflects the relationship between the design yield strength of the self - reset friction energy dissipator (4) and the yield strength of the frame beam, and the energy dissipator yield strength ratio is 0.3 - 0.

6.

9. A construction method for a self - reset prefabricated UHPC frame beam - column joint, characterized in that: It includes the following steps: S1: Fabricate a precast frame beam member (1), configure the steel bars required for the precast frame beam member (1). The longitudinal stressed steel bars specifically include three sections: "high - strength steel bar section (11)+non - bonded ordinary steel bar section (12)+bonded ordinary steel bar section (13)". Each section is connected by a connector (5). A backing plate one (14) for fixing the connecting plate is reserved at an appropriate position on the beam, and concrete is integrally poured to form the precast frame beam member (1); S2: Fabricate a precast frame column member (2), configure the steel bars required for the precast frame column member (2). A backing plate two (21) for fixing the connecting plate is reserved at an appropriate position on the column, and concrete is integrally poured to form the precast frame column member (2); S3: Connect the longitudinal stressed steel bars of the upper and lower precast frame column members (2) using a connector (5), and pour the beam - column joint area with ultra - high performance concrete (3); S4: Weld the gusset plate (6) to the backing plate one (14) and the backing plate two (21), and finally install the self - reset friction energy dissipator (4), which specifically includes 1 set of self - reset device (41) and 2 sets of rotational friction dampers (42). Each component is hinged to the gusset plate (6).

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