A nondestructive monitoring device and testing method for interface slip of steel-concrete composite structure

Abstract

The present invention provides a nondestructive monitoring device and test method for interface slip of steel-concrete composite structure, which relates to the technical field of structural health monitoring, including: a crank is arranged inside a shell, one end of a connecting rod is hinged with the crank, and the other end is connected to a gear set, the gear set is composed of a large gear and a small gear fixed and rotating coaxially, wherein the small gear is meshed with a fixed rack arranged inside the shell, and the large gear is meshed with a sliding rack arranged inside the shell and positioned by a track; the resistor group is divided into a long resistor block and a short resistor block, the long resistor block is fixed inside the shell, and the short resistor block is fixed to one end of the upper part of the sliding rack, and the surface of the long resistor block is in horizontal contact with the surface of the short resistor block; the signal acquisition system is electrically connected to the resistor group. The present invention amplifies the micro displacement of the structure, has high sensitivity, and reflects the slip state of the structure in real time, and the upper part of the device shell is fully enclosed, which can be applied to complex construction environments.

Description

Technical Field

[0001] The present invention relates to the technical field of structural health monitoring, and in particular to a non-destructive monitoring device and a testing method for interface slip of a steel-concrete composite structure. Background Art

[0002] The steel-concrete composite beam combines the steel beam and the concrete wing into a whole through shear connectors, giving full play to the tensile properties of steel and the compressive properties of concrete. Compared with steel structures, composite structures can save steel and have high rigidity; compared with concrete beams, composite structures have the advantages of light weight, good toughness, and good seismic performance. With the need to increase the span of bridges in recent years, steel-concrete composite structures have been widely used in the field of bridges.

[0003] Numerous studies have shown that various forms of shear connectors will deform when transmitting horizontal forces on the interface between steel and concrete, causing the composite structure to slip on the interface, weakening the overall stiffness and bearing capacity of the structure and reducing the working performance of the structure. Therefore, the relative slip amount of the steel-concrete interface is an important indicator reflecting the current working state and mechanical properties of the structure.

[0004] At present, a lot of research has been carried out on the slip problem of steel-concrete composite structures at home and abroad. Most of the research is carried out by means of simplified indoor experiments or finite element simulation. Due to the small relative slip amount of the composite structure interface, there are few targeted results on the effective monitoring method of the composite structure interface slip amount in actual engineering. Therefore, it is of great significance to study an effective non-destructive monitoring method to monitor the actual service structure in real time, which is of great significance for accurately evaluating the service performance of the structure and timely warning of dangerous information. Summary of the invention

[0005] The purpose of the present invention is to provide a nondestructive monitoring device for a steel-concrete composite structure interface and a testing method thereof, so as to solve the problem that it is difficult to effectively monitor the relative slip amount of the steel-concrete composite structure interface in real time in current practical engineering.

[0006] In order to achieve the above technical purpose, the present invention provides a non-destructive monitoring device for interface slip of a steel-concrete composite structure, comprising: a housing, a crank handle, a connecting rod, a gear set, a fixed rack, a sliding rack, a resistor set, and a signal acquisition system;

[0007] The crank is arranged inside the housing, one end of the connecting rod is hinged to the crank, and the other end is connected to the gear set;

[0008] The gear set is composed of a coaxial fixed corotating large gear and a small gear, wherein the small gear meshes with a fixed rack arranged inside the housing, and the large gear meshes with a sliding rack arranged inside the housing and positioned by a track;

[0009] The resistor group is composed of a long resistor block and a short resistor block, the long resistor block is fixed inside the housing, the short resistor block is fixed to one end of the upper part of the sliding rack, and the surface of the long resistor block is in horizontal contact with the surface of the short resistor block;

[0010] The signal acquisition system is electrically connected to the resistor group.

[0011] Preferably, the connecting rod is connected to the gear set via a gear shaft.

[0012] Preferably, grooves are prefabricated on both sides of the sliding rack, which are engaged with tracks arranged inside the shell, and the grooves are filled with lubricating oil.

[0013] Preferably, the long resistor block is fixed inside the housing via an insulating slot, the short resistor block is bonded to an upper end of the sliding rack via strong glue, and the surface of the long resistor block is in horizontal sliding contact with the surface of the short resistor block.

[0014] Preferably, an opening is provided on the side of the housing, and a signal line connected to the resistor group is led out through the opening and connected to the signal acquisition system, and then the opening is sealed with epoxy resin.

[0015] Preferably, the signal acquisition system comprises a connection terminal, a current acquisition module, an analog-to-digital conversion chip, a microcontroller unit and a storage and display part.

[0016] Preferably, one side of the crank handle is hinged to the transmission block via a transmission rod, an opening slot is provided at the bottom of the shell, and the transmission block extends to the outside of the shell through the opening slot and is flush with the shell.

[0017] Preferably, a screw hole is provided at the bottom of the transmission block.

[0018] A nondestructive monitoring test method for interface slip of a steel-concrete composite structure is applied to the nondestructive monitoring device for interface slip of a steel-concrete composite structure. The main body of the device is pre-buried in concrete to form a whole. The transmission block is connected to the steel beam top plate through the opening groove to form a whole. When relative slip occurs at the structural interface, the transmission block drives the crank inside the device to move, the gear set connected to the connecting rod rotates, and the displacement signal is converted into an electrical signal through the resistance block. The signal acquisition system collects and processes the electrical signal of the resistance block and reflects the specific value.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] During the design process of the present invention, the unfavorable factors that may exist during the installation and later measurement are fully considered. The upper part of the device is fully enclosed and can be applied to complex construction environments. The bottom of the device is connected to the steel beam top plate through a transmission block, which prevents concrete from entering the device during the pouring process and improves the monitoring performance. Since the relative slippage of the steel-concrete composite interface is very small, the use of a crank, a connecting rod and a gear set to cooperate with each other can greatly amplify the micro-displacement of the structure, and has high sensitivity, which can effectively reflect the displacement state of the structure and issue early warning information in time. The position of the crank is calibrated before the device is embedded. During the actual collection process, the displacement signal is converted into an electrical signal through a resistor group. The slippage degree and direction of the output interface can be changed according to the electrical signal, and the slippage state of the structure can be reflected in real time. The device is connected to a signal acquisition system, which can store and read the relative slippage state of the structure at any time, thereby realizing real-time monitoring of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 It is a specific installation diagram of the nondestructive monitoring device for the interface of a steel-concrete composite structure according to the present invention;

[0023] Figure 2 It is a schematic diagram of the internal structure of the nondestructive monitoring device for the interface of a steel-concrete composite structure according to the present invention;

[0024] Figure 3 This is a cross-sectional view of the nondestructive monitoring device for the interface of a steel-concrete composite structure described in the present invention.

[0025] In the figure, 1. steel beam, 2. concrete, 3. main body of the nondestructive monitoring device for the interface of steel-concrete composite structure, 4. signal acquisition system, 301. shell, 302. crank handle, 303. connecting rod, 3041. small gear, 3042. large gear, 3051. fixed rack, 3052. sliding rack, 3061. short resistor block, 3062. long resistor block, 307. track, 308. opening, 309. transmission rod, 310. transmission block. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0027] A nondestructive monitoring device for a steel-concrete composite structure interface and a testing method thereof are provided to solve the problem that it is difficult to effectively monitor the relative slip amount of a steel-concrete composite structure interface in real time in current practical engineering.

[0028] In order to achieve the above technical objectives, the present invention provides a nondestructive monitoring device for interface slip of a steel-concrete composite structure, comprising: a housing 301, a crank 302, a connecting rod 303, a gear set, a fixed rack 3051, a sliding rack 3052, a resistor group, and a signal acquisition system 4;

[0029] The crank 302 is disposed inside the housing 301, one end of the connecting rod 303 is hinged to the crank 302, and the other end is connected to the gear set. The length of the connecting rod 303 is three to five times that of the crank 302, and both have sufficient rigidity;

[0030] The gear set is composed of a coaxial fixed corotating large gear 3042 and a small gear 3041, wherein the small gear 3041 is meshed with a fixed rack 3051 disposed inside the housing 301, and the large gear 3042 is meshed with a sliding rack 3052 disposed inside the housing 301 and positioned by a track 307, and the fixed rack is fixed by a slot in the housing 301;

[0031] Furthermore, grooves are prefabricated on both sides of the sliding rack 3052, which are engaged with the rails 307 arranged inside the housing 301, and the grooves are filled with lubricating oil.

[0032] The resistor group is composed of a long resistor block 3062 and a short resistor block 3061. The long resistor block 3062 is fixed inside the housing 301, and the short resistor block 3061 is fixed to one end of the upper part of the sliding rack 3052. The surface of the long resistor block 3062 is in horizontal contact with the surface of the short resistor block 3061.

[0033] The housing 301 is rectangular or polygonal, with a height not exceeding 3 cm and a horizontal dimension not exceeding 15 cm, and is made of stainless steel or other hard and corrosion-resistant materials.

[0034] The signal acquisition system 4 is electrically connected to the resistor group.

[0035] Furthermore, the connecting rod 303 is connected to the gear set via a gear shaft.

[0036] Furthermore, the long resistor block 3062 is fixed inside the housing 301 through an insulating slot, and the short resistor block 3061 is bonded to an upper end of the sliding rack 3052 through strong glue. The surface of the long resistor block 3062 and the surface of the short resistor block 3061 are in horizontal sliding contact and are connected to the signal acquisition system 4.

[0037] Furthermore, an opening 308 is provided on the side of the housing 301 , and a signal line connected to the resistor group is led out through the opening 308 and connected to the signal acquisition system 4 , and then the opening 308 is sealed with epoxy resin.

[0038] Furthermore, the signal acquisition system 4 includes a power supply, a connection terminal, a current acquisition module, an analog-to-digital conversion chip, a microcontroller unit and a storage and display part, which can respond to tiny signals.

[0039] Furthermore, one side of the crank 302 is hinged to the transmission block 310 through a transmission rod 309, ensuring that when the device is displaced, the transmission block 309 can smoothly drive the crank 302 to rotate; an opening 308 groove is provided at the bottom of the shell 301, and the transmission block 310 extends to the outside of the shell 301 through the opening 308 groove and is flush with the shell 301.

[0040] Furthermore, a screw hole is provided at the bottom of the transmission block 310 for connection with the top plate of the steel beam 1 .

[0041] A nondestructive monitoring test method for interface slip of a steel-concrete composite structure is applied to the nondestructive monitoring device for interface slip of a steel-concrete composite structure. The main body of the device is pre-buried in concrete 2 to form a whole. The transmission block 310 is connected to the top plate of the steel beam 1 through the opening 308 groove to form a whole. When relative slip occurs at the structural interface, the crank handle 302 inside the device will be driven to move through the transmission block 310, and the gear set connected to the connecting rod 303 will rotate. The displacement signal is converted into an electrical signal through the resistance block. The signal acquisition system 4 collects and processes the electrical signal of the resistance block and reflects the specific value.

[0042] Installation method of nondestructive monitoring device for steel-concrete composite structure interface: Figure 1As shown, before the installation of the device, the bottom of the device and the top plate of the steel beam 1 need to be polished to ensure that the contact surfaces of the two are smooth; the device body 3 itself has a certain compressive stiffness and is pre-embedded in the concrete 2, and can work together with the concrete to form a whole; when the structural design allows drilling of the top plate of the steel beam 1, the transmission block 310 and the top plate of the steel beam 1 can be connected by bolting, which is convenient for the recycling of the device; when the structural design does not allow drilling of the top plate of the steel beam 1, the transmission block 310 and the top plate of the steel beam 1 can be connected by welding.

[0043] The assembly sequence of the device is as follows: Figure 2 As shown, the housing 301, crank 302, connecting rod 303, gear set, rack, resistor group, transmission rod 309 and transmission block 310 of the device are all processed in batches in advance in the factory. The housing 301 is prefabricated with the required fixing slots corresponding to the positions of each component. At the same time, one side of the housing 301 is left unsealed to facilitate the assembly of the device; first, the fixed rack 3051 and the long resistor block 3062 are installed inside the housing 301 through the fixed slots, and the short resistor block 3061 is bonded to the upper end of the sliding rack 3052 with strong glue, and then the sliding rack 3052 is installed at the corresponding position through the track 307; the transmission rod 30 9. The transmission block 310 is hinged on the crank 302 to form a whole, the crank 302, the connecting rod 303 and the gear group are connected, the position of the sliding rack 3052 is adjusted for calibration, and then the crank 302 is installed at the corresponding position inside the shell 301 and the meshing of the gear group and the rack is completed; the signal line connected to the resistor group is led out through the opening 308 and connected to the signal acquisition system 4, and a signal line of the required length for the movement of the short resistor block 3061 is reserved inside the shell, and the opening 308 is sealed with epoxy resin; after adjusting the position of the transmission rod 309 and the transmission block 310, the shell 301 can be sealed.

[0044] The monitoring principle of the device is: Figure 1 and Figure 2 The internal structure of the device is fine, and the components are closely connected, which can achieve effective response to the micro displacement of the structure. The main body 3 of the device is embedded in the concrete 2 to form a whole. The transmission block 310 in the device is connected to the top plate of the steel beam 1 through the opening groove at the bottom of the shell 301 to form a whole. When the structural interface slips relatively, the transmission block 310 will drive the crank 302 inside the device to move, and the gear set connected to the connecting rod 303 will rotate. The coordination of the crank, connecting rod and gear set improves the amplification efficiency of the micro displacement of the structure. The displacement signal is converted into an electrical signal through the resistor block, and the specific value is reflected after being collected and processed by the signal acquisition system 4. Before the device is installed, the relationship between the electrical signal increment and the displacement increment is determined by experiment, and the program is written into the signal acquisition system 4 to realize the mutual conversion between the electrical signal and the displacement signal.

[0045] During the design process of the present invention, the unfavorable factors that may exist during the installation and later measurement are fully considered. The upper part of the device is fully enclosed and can be applied to complex construction environments. The bottom of the device is connected to the steel beam top plate through a transmission block, which prevents concrete from entering the device during the pouring process and improves the monitoring performance. Since the relative slippage of the steel-concrete composite interface is very small, the use of a crank, a connecting rod and a gear set to cooperate with each other can greatly amplify the micro-displacement of the structure, and has high sensitivity, which can effectively reflect the displacement state of the structure and issue early warning information in time. The position of the crank is calibrated before the device is embedded. During the actual collection process, the displacement signal is converted into an electrical signal through a resistor group. The slippage degree and direction of the output interface can be changed according to the electrical signal, and the slippage state of the structure can be reflected in real time. The device is connected to a signal acquisition system, which can store and read the relative slippage state of the structure at any time, thereby realizing real-time monitoring of the structure.

[0046] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and are not to be understood as indicating or implying relative importance.

[0047] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can still modify the technical solutions described in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or perform equivalent replacements on some of the technical features thereof; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. They should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A non-destructive monitoring device for interface slip of steel-concrete composite structures. It is characterized in that include: Housing, crank handle, connecting rod, gear set, fixed rack, sliding rack, resistor group, signal acquisition system; The crank is arranged inside the housing, one end of the connecting rod is hinged to the crank, and the other end is connected to the gear set, and the length of the connecting rod is three to five times that of the crank; The gear set is composed of a coaxial fixed corotating large gear and a small gear, wherein the small gear meshes with a fixed rack arranged inside the housing, and the large gear meshes with a sliding rack arranged inside the housing and positioned by a track; The fixed rack and the sliding rack are arranged at two opposite sides of the housing, and the gear set is located between the fixed rack and the sliding rack; The resistor group is composed of a long resistor block and a short resistor block, the long resistor block is fixed inside the housing, the short resistor block is fixed to one end of the upper part of the sliding rack, and the surface of the long resistor block is in horizontal contact with the surface of the short resistor block; The signal acquisition system is electrically connected to the resistor group; The connecting rod is connected to the gear set via a gear shaft; One side of the crank handle is hinged to the transmission block through a transmission rod, and an opening slot is provided at the bottom of the shell. The transmission block extends to the outside of the shell through the opening slot and is flush with the shell.

2. The nondestructive monitoring device for interface slip of a steel-concrete composite structure according to claim 1, It is characterized in that The sliding rack has prefabricated grooves on both sides, which are engaged with the tracks arranged inside the shell, and the grooves are filled with lubricating oil.

3. The nondestructive monitoring device for interface slip of a steel-concrete composite structure according to claim 1 or 2, It is characterized in that The long resistor block is fixed inside the housing through an insulating slot, and the short resistor block is bonded to an upper end of the sliding rack through a strong glue, and the surface of the long resistor block is in horizontal sliding contact with the surface of the short resistor block.

4. The nondestructive monitoring device for interface slip of steel-concrete composite structure according to claim 1, It is characterized in that An opening is provided on the side of the shell, and a signal line connected to the resistor group is led out through the opening and connected to the signal acquisition system, and then the opening is sealed with epoxy resin.

5. The nondestructive monitoring device for interface slip of steel-concrete composite structure according to claim 4, It is characterized in that The signal acquisition system comprises a connection terminal, a current acquisition module, an analog-to-digital conversion chip, a micro control unit and a storage and display part.

6. The nondestructive monitoring device for interface slip of a steel-concrete composite structure according to claim 5, It is characterized in that The bottom of the transmission block is provided with a screw hole.

7. A nondestructive monitoring test method for interface slip of a steel-concrete composite structure, applied to the nondestructive monitoring device for interface slip of a steel-concrete composite structure as claimed in any one of claims 1 to 6, It is characterized in that The main body of the device is embedded in the concrete to form a whole, and the transmission block is connected to the steel beam top plate through the opening groove to form a whole. When the structural interface undergoes relative slip, the transmission block will drive the crank inside the device to move, and the gear set connected to the connecting rod will rotate. The displacement signal is converted into an electrical signal through the resistance block, and the signal acquisition system collects and processes the electrical signal of the resistance block and reflects the specific value.

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