Embedded intelligent aggregate self-sensing connector and connecting system

Abstract

The application relates to a self-sensing connecting piece with embedded intelligent aggregate and a connecting system, the connecting piece comprising a steel pipe (1), high-strength concrete (2) and piezoelectric intelligent aggregate (3); the high-strength concrete (2) is arranged in the steel pipe (1), and the piezoelectric intelligent aggregate (3) is arranged in the high-strength concrete (2); the connecting system comprises the self-sensing connecting piece with embedded intelligent aggregate, further comprises a first component and a second component, and the self-sensing connecting piece with embedded intelligent aggregate is arranged in the first component and connected with the second component. Compared with the prior art, the application provides the connecting piece with sufficient tensile bearing capacity and shearing bearing capacity, which can self-sense damage, and long-term and accurate monitoring of the performance of the connecting piece can be achieved.

Description

Technical Field

[0001] This invention relates to the field of connector technology, and in particular to an embedded intelligent aggregate self-sensing connector and connection system. Background Technology

[0002] In steel-concrete composite structures, the connectors at the interface between the steel and concrete are crucial components, ensuring that the steel and concrete members are connected as a whole and form a composite section that shares the load. As a fundamental requirement, the connectors at the interface must be able to resist the uplift deformation between the steel and concrete components and also transmit the shear force between them; that is, they must have sufficient tensile and shear bearing capacity.

[0003] During the service life of steel-concrete composite structures, the connectors will inevitably suffer damage under load and external environmental conditions, resulting in degradation of tensile and shear resistance. However, since the connectors are embedded inside the concrete, it is difficult to monitor and detect their damage, which brings difficulties to the operation and maintenance of steel-concrete composite structures and also poses potential safety hazards to the structure.

[0004] For the most widely used welded stud connectors and perforated plate connectors, strain gauges, fiber optic sensors, and other sensors are often attached to the connectors to monitor their stress or strain state. However, the durability of the adhesive is difficult to guarantee, and the contact surface between the connector and the concrete experiences significant pressure, friction, and deformation, causing the sensors to easily detach, resulting in distorted measurement results and hindering long-term monitoring. In addition, some monitoring methods involve placing sensors (such as piezoresistive sensors and piezoelectric smart aggregates) in the concrete surrounding the connector, aiming to indirectly infer the connector's damage state by measuring the stress or strain state within the concrete. However, the randomness and heterogeneity of the microscopic mechanical properties of ordinary concrete will negatively impact the testing accuracy of these sensors. Furthermore, because the concrete is in direct contact with the external environment, the test results of these sensors are easily affected by ambient humidity and harmful particle corrosion.

[0005] Currently, long-term and accurate monitoring of connector performance remains a key challenge for the operation and maintenance of steel-concrete composite structures, and there is still no reliable solution: on the one hand, traditional connectors have small geometric dimensions and are embedded in concrete, making them inconvenient to monitor; on the other hand, traditional monitoring methods are difficult to meet the requirements of long-term and accurate testing. Summary of the Invention

[0006] The purpose of this invention is to provide an embedded intelligent aggregate self-sensing connector and connection system with long-term monitoring capabilities.

[0007] The objective of this invention can be achieved through the following technical solution: an embedded intelligent aggregate self-sensing connector, comprising a steel pipe, high-strength concrete filling, and piezoelectric intelligent aggregate;

[0008] The high-strength concrete filling is placed inside the steel pipe, and piezoelectric smart aggregate is placed inside the high-strength concrete filling.

[0009] Preferably, one end of the steel pipe is connected to a cover plate, and the inner side of the other end is provided with piezoelectric smart aggregate.

[0010] More preferably, the outer diameter of the cover plate is larger than that of the steel pipe, forming a flange (i.e., the annular portion of the cover plate that extends laterally out of the steel pipe).

[0011] More preferably, the width of the flange is not less than 10 mm.

[0012] More preferably, the cover plate has an opening at its center, and the piezoelectric smart aggregate is connected to a wire, which extends out of the steel pipe through the opening.

[0013] Preferably, the diameter or minimum side length of the opening is not less than twice the diameter of the wire, so as to facilitate the wire extending out.

[0014] Preferably, the diameter of the conductor is 1.8 to 2.2 mm to ensure that the conductor is not easily damaged during the pouring process.

[0015] More preferably, the centroid of the cover plate cross section and the centroid of the steel pipe cross section are on the same straight line.

[0016] More preferably, the cover plate is a steel cover plate.

[0017] More preferably, the cover plate is made of the same steel plate thickness and material as the steel pipe.

[0018] Preferably, the aperture of the opening is smaller than the inner diameter of the steel pipe.

[0019] Preferably, the steel pipe is made of steel with a yield strength of not less than 235 MPa.

[0020] Preferably, the inner diameter or minimum side length of the steel pipe is not less than 15mm, the thickness of the steel pipe is not less than 4mm, and the height is not less than 4 times the inner diameter or minimum side length.

[0021] Preferably, the high-strength concrete is densely filled inside the steel pipe and flush with both ends of the steel pipe.

[0022] Preferably, the high-strength concrete filling comprises four main components: cement, sand, stone, admixtures such as high-efficiency water-reducing agents, and mineral admixtures such as fly ash, ultrafine slag, and silica fume, prepared using conventional processes.

[0023] Preferably, the size of the ordinary aggregate in the high-strength concrete filling is no greater than 3mm; fibers are added to improve its strength; it is self-compacting concrete with high fluidity.

[0024] More preferably, the fiber is steel fiber and / or basalt fiber.

[0025] More preferably, the high-strength concrete used for filling is ultra-high performance concrete reinforced with steel fibers.

[0026] More preferably, the ordinary aggregate includes crushed stone particles.

[0027] Preferably, the compressive strength of the high-strength concrete filling is not less than 60 MPa.

[0028] Preferably, the maximum size of the piezoelectric smart aggregate is no greater than half the inner diameter or minimum side length of the steel pipe, which facilitates the compaction of the high-strength concrete filling.

[0029] Preferably, the piezoelectric smart aggregate is located at the center of the bottom of the steel pipe.

[0030] Preferably, the piezoelectric smart aggregate is provided with an aggregate positioning element on its outer side.

[0031] More preferably, the piezoelectric smart aggregate has a cubic structure, and the aggregate positioning component includes plates disposed on the four sides of the piezoelectric smart aggregate to restrict the planar position of the piezoelectric smart aggregate inside the steel pipe.

[0032] More preferably, the sheet body and the piezoelectric smart aggregate are bonded together with epoxy resin.

[0033] More preferably, the sheet is made of PVC plastic.

[0034] More preferably, the sheet is a thin sheet with a thickness of 0.8 to 1.2 mm.

[0035] More preferably, the sheet is a triangular sheet.

[0036] More preferably, the height of the edge connecting the sheet to the piezoelectric smart aggregate is the same as that of the piezoelectric smart aggregate.

[0037] Preferably, the piezoelectric smart aggregate includes lead zirconate titanate sheet, protective shell and epoxy resin;

[0038] The lead zirconate titanate sheet is perpendicular to the main shear direction of the connector, and protective shells are provided on both sides of the lead zirconate titanate sheet, with epoxy resin filling the gap between the two protective shells.

[0039] More preferably, the plane containing the lead zirconate titanate sheet is perpendicular to the bonding surface of the combined structure, and is perpendicular to the main shear direction of the connecting member.

[0040] More preferably, the lead zirconate titanate sheet is disposed within the epoxy resin.

[0041] More preferably, the protective shell is marble, which gives the piezoelectric smart aggregate high strength.

[0042] The connector of this invention is applicable to steel and concrete composite structures or concrete composite structures.

[0043] An embedded intelligent aggregate self-sensing connection system includes the aforementioned embedded intelligent aggregate self-sensing connector, and further includes a first component and a second component. The embedded intelligent aggregate self-sensing connector is disposed within the first component and connected to the second component.

[0044] Preferably, the first component is a concrete component, the second component is a steel component, and the steel pipe is welded to the second component.

[0045] A construction method for the aforementioned embedded intelligent aggregate self-sensing connection system includes the following steps:

[0046] (1) Place the piezoelectric smart aggregate and aggregate positioning component inside a steel pipe with a cover plate, and extend the wires connected to the piezoelectric smart aggregate from the center opening of the cover plate.

[0047] (2) Weld the steel pipes onto the steel components;

[0048] (3) High-strength concrete is poured into the steel pipe through the opening in the center of the cover plate to obtain the connector;

[0049] (4) Pour concrete on the outside of the connector so that the connector is embedded in the concrete component.

[0050] Alternatively, a construction method for the above-mentioned embedded intelligent aggregate self-sensing connection system includes the following steps:

[0051] (1) Place the piezoelectric smart aggregate and aggregate positioning component inside a steel pipe with a cover plate, and extend the wires connected to the piezoelectric smart aggregate from the center opening of the cover plate.

[0052] (2) High-strength concrete is poured into the steel pipe through a hole made in the center of the cover plate to obtain the connector;

[0053] (3) Weld the steel pipe onto the steel component to connect the connector to the steel component;

[0054] (4) Pour concrete on the outside of the connector so that the connector is embedded in the concrete component.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] 1. This invention utilizes piezoelectric smart aggregate to achieve self-sensing. The smart aggregate is encased in a steel pipe filled with high-strength concrete, effectively isolating it from the influence of external environmental humidity and harmful particle corrosion. Simultaneously, the piezoelectric smart aggregate itself possesses good durability, enabling the connectors to perform long-term monitoring.

[0057] 2. This invention is a connector composed of a steel pipe and high-strength concrete filling, which has higher shear bearing capacity. The steel pipe can restrain the high-strength concrete filling, improving the concrete strength; the high-strength concrete filling can limit the instability deformation of the steel pipe, improving the steel pipe strength. At the same time, the flanged steel cover plate in this invention not only serves to seal the intelligent aggregate, but also provides the tensile bearing capacity of the combined connector.

[0058] 3. In this invention, the intelligent aggregate is embedded in the high-strength concrete filling and participates in the stress distribution of the composite connectors. Therefore, it directly monitors the stress or strain state of the connectors rather than indirectly, improving monitoring efficiency and accuracy. Simultaneously, the size of the ordinary aggregate in the high-strength concrete filling is no greater than 3mm, greatly reducing the inhomogeneity and randomness of the microscopic mechanical properties of the high-strength concrete filling, further improving monitoring accuracy.

[0059] 4. The high-strength concrete filling at the location of the intelligent aggregate of this invention has the greatest stress or strain and is more uniformly distributed, which helps to improve the monitoring accuracy.

[0060] 5. The stress or strain value at the intelligent aggregate of this invention is linearly related to the shear force transmitted by the connector within a certain range, which can directly monitor the stress on the connector. At the same time, once it enters a nonlinear change, it can determine whether there is damage to the connector.

[0061] 6. The tensile strength and shear strength of the connector of the present invention are mainly controlled by the cross-sectional bearing capacity of the steel pipe section, and it has good ductility. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the structure of the embedded intelligent aggregate self-sensing connector of the present invention;

[0063] Figure 2 This is a schematic diagram illustrating the connection between the embedded intelligent aggregate self-sensing connector and the second component of the present invention. Figure 1 ;

[0064] Figure 3 This is a schematic diagram illustrating the connection between the embedded intelligent aggregate self-sensing connector and the second component of the present invention. Figure 2 ;

[0065] Figure 4 This is a schematic diagram of the structure of the piezoelectric smart aggregate of the present invention;

[0066] Figure 5This is a schematic diagram of the structure of the embedded intelligent aggregate self-sensing connection system of the present invention;

[0067] Figure 6 This is a schematic diagram of the design principle of the steel pipe cross-section of the embedded intelligent aggregate self-sensing connection system of the present invention;

[0068] Figure 7 This is a schematic diagram of the shear force monitoring direction of the embedded intelligent aggregate self-sensing connection system of the present invention;

[0069] Figure 8 This is a top view showing the horizontal arrangement of the buried intelligent aggregate self-sensing connector of the present invention.

[0070] In the figure: 1-steel pipe, 2-inner high-strength concrete, 3-piezoelectric smart aggregate, 31-lead zirconate titanate sheet, 32-protective shell, 33-epoxy resin, 4-cover plate, 41-flange, 5-wire, 6-aggregate positioning component, 7-first component, 8-second component, a-connector. Detailed Implementation

[0071] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0072] Example 1

[0073] An embedded intelligent aggregate self-sensing connector, such as Figure 1 As shown, it includes a steel pipe 1, high-strength concrete 2 filled inside, and piezoelectric smart aggregate 3. The high-strength concrete 2 is placed inside the steel pipe 1, and the piezoelectric smart aggregate 3 is placed inside the high-strength concrete 2.

[0074] This embodiment utilizes piezoelectric smart aggregate to achieve self-sensing. The piezoelectric smart aggregate is encased in a steel pipe filled with high-strength concrete, effectively isolating it from the influence of external environmental humidity and harmful particle corrosion. Simultaneously, the piezoelectric smart aggregate itself possesses good durability, enabling the connectors to perform long-term monitoring.

[0075] Example 2

[0076] An embedded intelligent aggregate self-sensing connector, such as Figure 2 As shown, a cover plate 4 is connected to the top of the steel pipe 1, and a connecting component is connected to the bottom. A piezoelectric smart aggregate 3 is provided on the inner side of the bottom of the steel pipe 1. The cover plate 4 covers the hole above the steel pipe 1, and its outer diameter is larger than that of the steel pipe 1, forming a flange 41. An opening is provided in the center of the cover plate 4, and the wire 5 connected to the piezoelectric smart aggregate 3 extends out of the steel pipe 1 through the opening. The rest is the same as in Embodiment 1.

[0077] Example 3

[0078] An embedded intelligent aggregate self-sensing connector, such as Figure 3 As shown, the piezoelectric smart aggregate 3 has a cubic structure. An aggregate positioning element 6 is provided on the outer side of the piezoelectric smart aggregate 3. The aggregate positioning element 6 includes triangular pieces disposed on the four sides of the piezoelectric smart aggregate 3. The structure of the piezoelectric smart aggregate 3 is as follows: Figure 4 As shown, the connector includes a lead zirconate titanate sheet 31, a protective shell 32, and epoxy resin 33. The lead zirconate titanate sheet 31 is perpendicular to the main shear direction of the connector. Protective shells 32 are provided on both sides of the lead zirconate titanate sheet 31, and the gap between the two protective shells 32 is filled with epoxy resin 33. The wire 5 is connected to the lead zirconate titanate sheet 31. The rest is the same as in Example 2.

[0079] Example 4

[0080] An embedded intelligent aggregate self-sensing connector is provided. In this embodiment, the interior of the steel pipe 1 is filled with high-strength concrete 2. The piezoelectric intelligent aggregate 3 and the aggregate positioning component 6 are embedded in the high-strength concrete 2. The steel cover plate 4 is welded to the upper edge of the steel pipe 1 and covers the hole above the steel pipe 1. The lower part of the steel pipe 1 is welded to the steel component (second component 8) of the combined structure.

[0081] Steel pipe 1 is a round steel pipe with an inner diameter of 20mm, a thickness of 4mm, and a height of 80mm, and is made of Q345 steel.

[0082] The high-strength concrete 2 inside is an ultra-high performance concrete with a compressive strength of 120MPa, no coarse aggregate, and steel fiber, which has the characteristics of self-compacting and high fluidity. The height of the filling is equal to the height of the steel pipe 1.

[0083] The steel cover plate 4 is a disc with a diameter of 29mm and a thickness of 4mm. It has a through hole with a diameter of 10mm in the middle, and its flange 41 extends outward with a width of 15mm. It is made of Q345 steel.

[0084] The piezoelectric smart aggregate 3 is mainly composed of lead zirconate titanate sheet 31, marble protective shell 32, and epoxy resin 33, and is connected by wire 5. The lead zirconate titanate sheet 31 has a side length of 5mm and a thickness of 0.3mm. The plane of the lead zirconate titanate sheet 31 is perpendicular to the interface between the steel and concrete, and perpendicular to the main shear direction of the connector. The two marble protective shells 32 are cuboids with a side length of 7mm and a thickness of 3mm. The wire 5 has a diameter of 2mm.

[0085] The aggregate positioning piece 6 is a triangular PVC plastic sheet with a thickness of 1mm, and one side of the triangle is the same height as the piezoelectric smart aggregate 3. The four aggregate positioning pieces 6 are bonded to the piezoelectric smart aggregate 3 with epoxy resin, which restricts the piezoelectric smart aggregate 3 to the center of the bottom of the steel pipe 1.

[0086] Example 5

[0087] A self-sensing steel-concrete composite connector a with embedded intelligent aggregate, used for connecting steel and concrete composite structures, includes a steel pipe 1, high-strength concrete 2, piezoelectric intelligent aggregate 3, a steel cover plate 4, a wire 5, and aggregate positioning components 6. The high-strength concrete 2 fills the interior of the steel pipe 1. The piezoelectric intelligent aggregate 3 and aggregate positioning components 6 are embedded within the high-strength concrete 2. The steel cover plate 4 is welded to the upper edge of the steel pipe 1 and covers the opening above the steel pipe 1. The lower part of the steel pipe 1 is welded to the steel component (second component 8) of the composite structure. The steel pipe 1 and the high-strength concrete 2 work together to transmit the shear force between the steel and concrete components; for example... Figure 5 As shown, the steel cover plate 4 is embedded in the concrete component (first component 7) of the composite structure, and resists the uplift deformation between the steel and concrete components through its flange; the piezoelectric smart aggregate 3 embedded in the high-strength concrete 2 can realize the self-sensing of the damage of the connector by monitoring the stress or strain state of the high-strength concrete 2 in the steel pipe concrete composite connector.

[0088] like Figure 6 As shown, the cross-section of the steel pipe is circular, rectangular, or square, which needs to be determined according to the shear force direction on the interface between the steel and concrete composite structure: if there is shear force in all directions, a circular shape is used; if the shear force is mainly in two perpendicular directions, a square shape is used; if the shear force is mainly in one direction, a rectangular shape is used, with the long side along that direction.

[0089] Example 6

[0090] A self-sensing steel-concrete composite connector 'a' with embedded intelligent aggregate is used for connecting steel and concrete composite structures. When there are two or more shear force directions on the interface between the steel and concrete composite structure, in addition to the corresponding design of the steel pipe cross-section, multiple connectors 'a' with different shear force monitoring directions need to be arranged in the steel and concrete composite structure. To facilitate the arrangement of connectors 'a', the shear force monitoring direction of connector 'a' is defined as the normal direction of the plane containing the lead zirconate titanate sheet 31 inside the piezoelectric intelligent aggregate 3. A pair of aggregate positioning elements 6 can be arranged in this direction. To facilitate orientation during installation, markings or coloring can be made on the aggregate positioning elements 6, and then another pair of aggregate positioning elements 6 are arranged on the plane containing the lead zirconate titanate sheet 31. Figure 7 As shown, the direction of the horizontal line mark on the aggregate positioning component 6, which is perpendicular to the plane of the lead zirconate titanate sheet 31, is the direction of shear force monitoring.

[0091] When multiple connectors 'a' are arranged along a rectangular array, the transverse arrangement of connectors 'a' should ensure the completeness of the shear force monitoring direction as much as possible, for example... Figure 8 As shown, if there are 4 connectors a in each row in the transverse direction, the shear force monitoring directions of each connector a should be arranged at 45° intervals. The rest is the same as in Example 5.

[0092] This invention provides a connector with sufficient tensile and shear strength and the ability to self-detect damage, enabling long-term and accurate monitoring of connector performance.

[0093] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. An embedded intelligent aggregate self-sensing connection system, characterized in that, It includes an embedded intelligent aggregate self-sensing connector, a first component, and a second component. The embedded intelligent aggregate self-sensing connector is disposed in the first component and connected to the second component. The embedded intelligent aggregate self-sensing connector includes a steel pipe (1), high-strength concrete (2) filled inside, and piezoelectric intelligent aggregate (3). The high-strength concrete (2) is densely filled inside the steel pipe (1) and flush with both ends of the steel pipe (1). Piezoelectric smart aggregate (3) is installed inside the high-strength concrete (2). One end of the steel pipe (1) is connected to a cover plate (4), and the other end is provided with a piezoelectric smart aggregate (3); the outer diameter of the cover plate (4) is larger than that of the steel pipe (1), forming a flange; The first component is a concrete component, the second component is a steel component, and the steel pipe (1) is welded to the second component.

2. The embedded intelligent aggregate self-sensing connection system according to claim 1, characterized in that, The cover plate (4) has an opening in the center, and the piezoelectric smart aggregate (3) is connected to a wire (5). The wire (5) extends out of the steel pipe (1) through the opening.

3. The embedded intelligent aggregate self-sensing connection system according to claim 1, characterized in that, The piezoelectric smart aggregate (3) is provided with an aggregate positioning component (6) on its outer side.

4. The embedded intelligent aggregate self-sensing connection system according to claim 3, characterized in that, The piezoelectric smart aggregate (3) has a cubic structure, and the aggregate positioning component (6) includes a triangular piece disposed on the side of the piezoelectric smart aggregate (3).

5. The embedded intelligent aggregate self-sensing connection system according to claim 1, characterized in that, The piezoelectric smart aggregate (3) includes lead zirconate titanate sheet (31), protective shell (32) and epoxy resin (33). The lead zirconate titanate sheet (31) is perpendicular to the main shear direction of the connector. Protective shells (32) are provided on both sides of the lead zirconate titanate sheet (31), and epoxy resin (33) is filled between the two protective shells (32).

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