Intelligent reinforcing steel bar sleeve grouting lap joint

Abstract

The utility model provides an intelligent reinforcing steel bar sleeve grouting lap joint, and belongs to the technical field of assembly type building sleeve grouting joints. The problem that an existing sleeve grouting connector cannot detect the quality of grouting materials and the quality of internal steel bars at the same time is solved. Comprising a sleeve, a grouting hole, a grout outlet hole, an intelligent aggregate hole and an intelligent steel bar hole are formed in the sleeve, two parallel positioners are fixed in the sleeve, one positioner is located on the outer side of the grout outlet hole, and the other positioner is located on the outer side of the grouting hole. Intelligent aggregates for detecting compactness, strength and crack signals of a grouting material are embedded in the two positioners respectively, and the two intelligent aggregates are located on the same center line and are oppositely arranged; reserved intelligent steel bars are fixed to the two ends of the sleeve wall of the sleeve correspondingly, and optical fiber sensors used for monitoring stress and strain of the steel bars are arranged on the reserved intelligent steel bars. The sleeve is applied to the prefabricated beam column.

Description

Technical Field

[0001] The utility model provides an intelligent steel bar sleeve grouting lap joint, belonging to the technical field of assembled building sleeve grouting lap joints. Background Art

[0002] Prefabricated buildings are a fast, efficient and environmentally friendly construction method that has been widely used. However, the degree of intelligence and informationization of prefabricated buildings is relatively low, especially in the field of steel sleeve grouting connection. At present, the defects and shortcomings of the existing sleeve grouting technology are as follows:

[0003] 1. Grouting quality inspection is difficult:

[0004] ① At present, the means of testing the grouting quality are relatively limited. There is a lack of effective non-destructive testing technology and equipment, which makes it impossible to conduct a comprehensive and accurate test on the grouting quality, and it is difficult to effectively check the grouting density and whether the grouting material is cracked;

[0005] ② In the context of low intelligence, traditional quality inspection methods, such as endoscopy, rely on the visual perception and experience of on-site workers. This will lead to inconsistent inspection results, because manual inspection is affected by subjective factors, and it is difficult to ensure that the quality inspection of each sleeve is accurate.

[0006] 2. It is difficult to detect the strength of the grouting material in the sleeve:

[0007] ① Traditional testing methods have great limitations: Traditional grouting material strength testing methods, such as pull-out tests and drilling sampling tests, require destructive operations on site, which have limitations such as high difficulty in operation, destructive testing, and high cost. Destructive testing of structures is unacceptable for some structures that have been put into use or need to maintain integrity. Destructive testing methods will not only damage the structure, but also greatly increase the cost of structural repair.

[0008] ② The detection of the solid strength of the grouting material has not attracted widespread attention in the industry: there is no effective non-destructive testing technology applied to the solid strength detection of the grouting material in the sleeve.

[0009] 3. Lack of full-life cycle quality testing methods: There is a lack of effective full-life cycle quality testing methods for the grouting quality and strength of the grouting material in the sleeve, which leads to the inability to fully and accurately test the quality and performance of the grouting material at each stage. The lack of effective full-life cycle quality testing methods has brought a series of problems to the quality and strength testing of the grouting material inside the sleeve, mainly including:

[0010] ① Limitations in the construction phase: During the construction process, due to the lack of real-time and effective quality inspection methods, it is difficult to detect and deal with grouting problems in a timely manner. This leads to grouting quality defects in the subsequent stages and increases the cost of repair.

[0011] ② Unable to detect the safety and durability of the structure over a long period of time: After the structure is put into use, the lack of quality inspection methods throughout the entire life cycle makes it difficult to monitor the long-term performance of the grouting material inside the sleeve.

[0012] ③ No early warning: There is a lack of advance warning mechanism to detect potential defects or performance degradation of grouting materials before problems occur. This results in remedial actions being taken only after the problem occurs, increasing the difficulty of repair and maintenance.

[0013] ④ Difficulty in conducting post-disaster quality assessment: The structure may be affected by various changes during use, such as typhoons, earthquakes, changes in loads and environmental conditions. The lack of quality inspection methods throughout the life cycle makes it difficult to timely detect the impact of earthquakes on the performance of the grouting material in the sleeve.

[0014] 4. Lack of quality monitoring and evaluation of the steel bars in the sleeve: The existing sleeve grouting joints do not monitor the stress state, stress and strain of the steel bars in the sleeve, and cannot detect steel bar damage and potential problems in time. The strain gauges commonly used to measure the strain of steel bars have the disadvantages of being difficult to stick, easily damaged, greatly affected by temperature, easy to fail and poor durability, and are not suitable for long-term detection of steel bars in the sleeve. Utility Model Content

[0015] In order to solve the problem that the existing sleeve grouting joint cannot simultaneously detect the quality of the grouting material and the internal steel bar quality, the utility model proposes an intelligent steel bar sleeve grouting lap joint, the purpose of which is to realize the simultaneous detection of the quality of the grouting material and the steel bar by improving the internal structure of the sleeve and the steel bar structure.

[0016] In order to solve the above technical problems, the technical solution adopted by the utility model is: an intelligent steel bar sleeve grouting lap joint, comprising a sleeve, one end of the sleeve is provided with a grouting hole, the other end of the sleeve is provided with a grouting hole, the sleeve is also provided with an intelligent aggregate hole and an intelligent steel bar hole, two parallel positioners are fixed inside the sleeve, one positioner is located outside the grouting hole, and the other positioner is located outside the grouting hole, and the two positioners are respectively embedded with intelligent aggregates for detecting the density, strength and crack signals of the grouting material, the two intelligent aggregates are located on the same center line and are arranged opposite to each other, and the wires of the two intelligent aggregates are respectively connected to one end of two copper shafts after passing through the two intelligent aggregate holes, and the copper shafts are fixed outside the sleeve;

[0017] Reserved smart steel bars are fixed to both ends of the sleeve wall respectively, and optical fiber sensors for monitoring the stress and strain of the steel bars are arranged on the reserved smart steel bars.

[0018] The grouting hole and the grouting hole are located on the same side of the sleeve.

[0019] The grouting hole and the grouting hole are located on the same center line.

[0020] The two positioners are on the same plane as the grouting holes and the grouting holes.

[0021] The other end of the optical fiber sensor passes through the intelligent steel bar hole and is connected to an external optical fiber modem. The optical fiber modem is connected to a data acquisition card via a wire. The data acquisition card is also connected to a display control terminal via a wire. The other ends of the two copper shafts are respectively connected to the data acquisition card via wires.

[0022] The smart aggregate adopts piezoelectric smart aggregate, which is arranged in a circular ring shape, including a piezoelectric ceramic sheet and a shielding wire. The piezoelectric ceramic sheet welded to the shielding wire is placed inside the circular ring. The upper and lower surfaces of the circular ring adopt epoxy resin as the outer packaging and waterproof layer. A circular notch for the outlet of the shielding wire is opened at one end of the circular ring.

[0023] The positioner is made of a steel plate, a circular hole is cut in the middle of the steel plate, and the smart aggregate is pasted in the circular hole.

[0024] The reserved smart steel bar includes a ribbed steel bar, on which a groove for fixing the optical fiber sensor is opened, a part of the optical fiber sensor is fixed in the groove of the ribbed steel bar, and another part of the optical fiber sensor passes through the hole of the smart steel bar and extends out of the sleeve.

[0025] The optical fiber sensor adopts a fully distributed optical fiber sensor for measuring the strain of the entire length of the steel bar or a point optical fiber sensor for measuring the strain at both ends and in the middle of the steel bar.

[0026] The data acquisition card collects the density data of the grouting material by stimulating the intelligent aggregate to transmit and receive five peak pulse wave signals with a frequency lower than 5kHz;

[0027] The data acquisition card collects the grouting material strength data by stimulating the intelligent aggregate to transmit and receive 100Hz-1kHz frequency sinusoidal periodic signals;

[0028] The data acquisition card collects the crack data of the grouting material by stimulating the intelligent aggregate to transmit and receive the sinusoidal periodic signal with a frequency of 100Hz-10kHz.

[0029] The beneficial effects of the utility model compared with the prior art are:

[0030] 1. Comprehensive and effective non-destructive testing: The smart sleeve can be equipped with smart aggregates to more accurately detect the quality and performance of grouting materials and improve testing efficiency:

[0031] ① Sleeve density detection: The utility model adopts built-in intelligent aggregate to transmit and receive signals to detect the density of grouting materials, which has the advantages of low cost, simple operation and sensitive response.

[0032] ② Strength monitoring of grouting materials: The utility model adopts built-in intelligent aggregate to transmit and receive signals to monitor the strength of grouting materials, which has the advantages of convenient operation, sensitive response and non-destructive structure.

[0033] ③ Crack damage identification: The utility model adopts built-in intelligent aggregate to realize the crack damage identification inside the structure, which is more intuitive and convenient.

[0034] Smart steel bars are made of traditional ribbed steel bars embedded with optical fiber sensors. Optical fiber sensors have the advantages of high sensitivity, lightness, flexibility, easy installation and burial, electrical insulation, good chemical stability, anti-electromagnetic interference, distributed measurement, long service life, large transmission capacity, strong durability, and not susceptible to external damage. These advantages make optical fiber sensors have great advantages in long-term monitoring and measurement in complex environments.

[0035] Smart steel bars can monitor the strain and stress of steel bars, providing reliable data on the health of the structure:

[0036] ① Steel bar strain: Fiber optic sensors can measure the strain of steel bars, that is, the strain of steel bars under external forces. This is very important for monitoring structural deformation, load response, and structural health status.

[0037] ②Rebar fatigue monitoring: Fiber optic sensors can help monitor the fatigue condition of steel bars and promptly detect fatigue loads that may cause structural damage.

[0038] 2. Early monitoring and warning:

[0039] ①Through density testing during the grouting process, grouting defects can be discovered in time and preventive measures can be taken, such as timely grouting, to avoid potential structural quality and safety problems.

[0040] ② The early strength of the grouting material, such as 24-hour strength, 3-day strength, 7-day strength and 28-day strength, can be tested. If the strength does not meet the design requirements, it can be repaired in time during the construction stage.

[0041] 3. Full life cycle performance tracking: Smart aggregates can help monitor the performance of the grouting material in the sleeve during its service life. By monitoring the strength, density and crack changes of the grouting material, potential quality problems can be discovered and resolved in a timely manner to ensure the safety and durability of the structure.

[0042] By monitoring strain throughout the life cycle, smart rebar helps optimize maintenance strategies, extend structural life, and improve structural reliability and safety, thereby achieving more sustainable, economical and safe structural performance throughout the life cycle.

[0043] 4. Post-disaster assessment and recovery: After a disaster (natural disasters and environmental changes), the smart sleeve can quickly detect the condition of the grouting material, thereby helping engineers assess the status of the overall structure and assist in post-disaster building restoration work.

[0044] Smart rebar can provide detailed data about the loads and strains experienced by a structure during a disaster. This data is essential to assess the actual impact of a disaster on a structure and whether the building is still safe and usable.

[0045] 5. Low full-cycle cost: The use of intelligent steel sleeves in prefabricated construction projects can significantly reduce the full-cycle cost from a long-term perspective, which is specifically reflected in the following aspects:

[0046] ① Reduce maintenance and repair costs: Intelligent steel sleeves reduce the need and frequency of major repairs and structural renovations that may occur in the future through real-time monitoring and early defect detection. Early detection and resolution of problems is more economical than repairing long-term damage, and repairs completed during the construction phase are more time-saving and cost-effective than repairs during the use phase.

[0047] ② Extend the life of the structure: Continuous monitoring of the quality of grouting materials helps to better maintain the prefabricated structure, thereby extending its service life. Extending the life of the structure and reducing the frequency of maintenance means longer use time and significantly reduces the cost per unit time.

[0048] ③ Long-term and repetitive testing: Existing testing is a one-time quality test during the construction phase, while smart aggregates embedded in the sleeve can be used for long-term and repetitive testing, providing a reliable and efficient means for the health management of buildings and structures.

[0049] Applying intelligent technology to steel sleeve grouting lap joints is meaningful and has great engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The utility model is further described below in conjunction with the accompanying drawings:

[0051] Figure 1It is a schematic diagram of the overall three-dimensional structure of the sleeve grouting lap joint in the first embodiment of the utility model;

[0052] Figure 2 for Figure 1 A front view of

[0053] Figure 3 for Figure 1 A top view of

[0054] Figure 4 This is a schematic diagram of the structure of the intelligent steel bar in the first embodiment of the utility model;

[0055] Figure 5 It is a schematic diagram of the overall three-dimensional structure of the sleeve grouting lap joint in the second embodiment of the utility model;

[0056] Figure 6 This is a schematic diagram of the structure of the intelligent steel bar in the second embodiment of the utility model;

[0057] Figure 7 Schematic diagram of the placement position of the intelligent aggregate in Embodiments 1 and 2 of the present utility model;

[0058] Figure 8 It is a structural schematic diagram of the positioner and the intelligent aggregate in the first and second embodiments of the utility model;

[0059] In the figure: 1 is the reserved intelligent steel bar, 2 is the post-inserted steel bar, 3 is the sleeve, 4 is the grouting hole, 5 is the slurry outlet hole, 6 is the intelligent aggregate hole, 7 is the intelligent steel bar hole, 8 is the positioner, 9 is the copper shaft, 10 is the data acquisition card, 11 is the display terminal, 12 is the intelligent aggregate, 101 is the ribbed steel bar, 102 is the fully distributed optical fiber sensor, and 103 is the point optical fiber sensor. DETAILED DESCRIPTION

[0060] like Figures 1 to 8 As shown, the utility model provides an intelligent steel bar sleeve grouting lap joint, including a sleeve 3, wherein the sleeve 3 is an approximately elliptical sleeve formed by butt welding two semi-elliptical steel plates, and a grouting hole 4 and a grouting hole 5 are respectively provided at both ends of one side of the sleeve 3, and intelligent aggregate holes 6 for the outlet of intelligent aggregate 12 are also provided at both ends of the sleeve 3, and an intelligent steel bar hole 7 for reserving the outlet of intelligent steel bar 1 is also provided at one end of the sleeve 3, and two positioners 8 are fixed inside the sleeve 3, and the positioners 8 are embedded with intelligent aggregate 12 for detecting the density, strength and cracks of the grouting material, and the two intelligent aggregates 12 are located on the same center line and arranged opposite to each other, and the positions of the two positioners 8 are located outside the grouting hole 4 and the grouting hole 5, so that one of the two intelligent aggregates 12 is lower than the grouting hole 4, and the other is higher than the grouting hole 5, thereby ensuring the accuracy of the grouting material detection.

[0061] The two ends of the sleeve 3 are respectively spot-welded with reserved intelligent steel bars 1, and one end of the reserved intelligent steel bars 1 is to extend out of the sleeve 3, so as to facilitate the subsequent assembly of prefabricated beams or prefabricated columns. The reserved intelligent steel bars 1 are provided with optical fiber sensors to monitor the stress and strain of the steel bars, and the other end of the optical fiber sensor on the reserved intelligent steel bars 1 is connected to the optical fiber modem after passing through the intelligent steel bar hole 7, and the optical fiber modem is then connected to the data acquisition card 10, and the data acquisition card 10 is connected to the display control terminal 11. The copper shaft 9 is fixed on the outside of the intelligent aggregate hole 6, and the outlet wires of the two intelligent aggregates 12 are welded to one end of the copper shaft 9, and the other end of the copper shaft 9 is connected to the data acquisition card 10. The display control terminal 11 can be a terminal device capable of computing and displaying, such as a laptop or desktop computer, and the data acquisition card 10 integrates the transmission signal and the acquisition signal to realize the synchronous acquisition and transmission of the signal, stimulate the intelligent aggregate 12 to generate a monitoring signal, and collect the signal of the density, strength and cracks of the grouting material.

[0062] Among them, the intelligent aggregate 12 adopts piezoelectric intelligent aggregate, and the core components of the piezoelectric intelligent aggregate are piezoelectric ceramic sheets and shielded wires. The utility model uses the lead zirconate titanate (PZT) piezoelectric ceramic sheets commonly used in health monitoring. According to the requirements of different functions, the PZT-4 piezoelectric ceramic sheet has the dual functions of transmitting and receiving. It can transmit signals of general frequencies and receive most signals. It has high sensitivity, so it best meets the monitoring requirements. The piezoelectric intelligent aggregate sensor is made with this as the core component. The parameters of the PZT-4 piezoelectric ceramic sheet are shown in Table 1 below. The shielded wire is a bridge connecting the piezoelectric ceramic sheet and the external receiving and signaling device. Its quality plays a vital role in the entire device. At present, there are many types of shielded wires. In view of the problem of positive and negative poles of piezoelectric ceramic sheets, the utility model uses a double-wire shielded wire with a built-in plastic protective layer and a copper wire mesh to make its shielding performance higher and enhance the stability of the signal. One end of the shielded wire is welded to the piezoelectric ceramic sheet, and the other end is welded to the copper shaft 8.

[0063]

[0064] Table 1 PZT-4 piezoelectric ceramic parameters.

[0065] The smart aggregate 7 is in the shape of a ring. The upper and lower surfaces of the ring are encapsulated and waterproofed with epoxy resin. A circular notch with a diameter slightly larger than the shielding wire is left at one end of the ring to facilitate the lead-out of the shielding wire. The piezoelectric ceramic sheet welded with the shielding wire is placed inside the ring. The mold is used to make the piezoelectric smart aggregate. The mold consists of a white steel bar with a protruding ring welded in the middle, such as Figure 8 As shown, the ring is used for forming the piezoelectric smart aggregate. By controlling the diameter of the ring to 3cm~4cm and the thickness to 2.5cm~3cm, the piezoelectric smart aggregate can be ensured to have a suitable volume and a certain strength.

[0066] During production, first add about 10mm thick epoxy resin curing agent into the mold. After air drying for a period of time, put in the piezoelectric ceramic sheet welded with the wire, and then add epoxy resin to fill the ring. This method ensures that the piezoelectric ceramic sheet maintains a horizontal position in the manufactured smart aggregate 12, ensures the accuracy of the signal transmission-reception direction, and reduces errors. The piezoelectric smart aggregate does not need to be demolded. After the inside of the ring is filled with epoxy resin, the steel shaft 9 is welded to the other side of the shielded wire. It can be used after the epoxy resin is cured. In addition to being used as a mold for the smart aggregate 12, the ring will also play a role in lateral shielding during the use stage to reduce the impact of lateral external noise.

[0067] There are two ways to implement the reserved intelligent steel bar 1, such as Figure 4 For an implementation structure, the reserved smart steel bar 1 includes a ribbed steel bar 101 and a fully distributed optical fiber sensor 102, a part of the fully distributed optical fiber sensor 102 is fixed on the ribbed steel bar 101, and another part of the fully distributed optical fiber sensor 102 is bent and passes through the smart steel bar hole 7 and extends out of the sleeve 3; Figure 6 As another implementation structure, the reserved intelligent steel bar 1 includes a ribbed steel bar 101 and a point optical fiber sensor 103, a part of the point optical fiber sensor 103 is fixed on the ribbed steel bar 101, and the other part of the point optical fiber sensor 103 is bent and passes through the intelligent steel bar hole 7 to extend out of the sleeve 3. The difference between the two is: the fully distributed optical fiber sensor 102 can measure the full-length strain of the reserved steel bar in the sleeve 3, and has a higher sensitivity, but the disadvantage is that the cost is high. The point optical fiber sensor 103 has higher accuracy and resolution when measuring strain, and the cost is low. However, it can only measure the strain at a specific point. In the utility model, the point distributed optical fiber sensor 103 is used to measure the strain at both ends of the reserved steel bar anchored in the sleeve 3 and in the middle of the steel bar. In actual use, different optical fiber arrangements can be adopted according to different measurement requirements.

[0068] The detection steps of the utility model are as follows:

[0069] Step 1: Make the sleeve 3. Weld two semi-elliptical steel plates together to form an approximately elliptical sleeve 3. Figure 1 and Figure 5 A grouting hole 4 and a grouting hole 5 are opened (in terms of the sleeve placement direction), smart aggregate holes 6 are opened at both ends of the sleeve 3, and smart steel bar holes 7 are opened on the left and right sides of the upper part of the sleeve 3.

[0070] Step 2: Make the reserved smart steel bar 1, use a grinder to groove the traditional ribbed steel bar 101, polish the surface with sandpaper, clean it with absorbent cotton and acetone, use glue to fix the fully distributed optical fiber sensor 102 or part of the point optical fiber sensor 103 in the groove of the ribbed steel bar 101, apply epoxy adhesive, and complete the production of the reserved smart steel bar 1.

[0071] Step 3: Place the positioner 8 and the smart aggregate 12 in the sleeve 3.

[0072] The locator 8 is made of steel plate, a circular hole is cut in the middle of the steel plate, and the smart aggregate 12 is pasted into the circular hole. The two locators 8 are welded to the upper and lower ends of the sleeve 3 respectively, and the two smart aggregates 12 located in the upper and lower locators 8 are opposite to each other. The wire passes through the sleeve 3 from the smart aggregate hole 6 and is connected to the copper shaft 9.

[0073] Step 4: First, spot weld the reserved smart steel bar 1 at both ends of the cylinder wall to fix the position of the steel bar, and pass the optical fiber sensor through the sleeve 3 from the smart steel bar hole 7.

[0074] Step 5: Place the rear-inserted steel bar 2 in the sleeve 3.

[0075] Step 6: Inject grouting material from the grouting port 4 and stop grouting when the grout overflows from the grouting hole 5.

[0076] Step 7: After the grouting is completed, the density test is carried out: the smart aggregate 12 is connected to the copper shaft 9, the data acquisition card 10 is connected to the copper shaft 9, and the data acquisition card 10 is connected to the display control terminal 11 at the same time. The data acquisition card 10 integrates the transmission signal and the collection signal to realize the synchronous collection and transmission of the signal, stimulate the smart aggregate 12 to generate a monitoring signal, and perform the density test of the grouting material.

[0077] Step 8: Maintenance.

[0078] Step 9: After the maintenance is completed, carry out strength testing: stimulate the smart aggregate 12 to generate a monitoring signal through the data acquisition card 10 to carry out strength testing of the grouting material.

[0079] Step 10: Conduct crack damage identification: Use the data acquisition card 10 to stimulate the intelligent aggregate 12 to generate a monitoring signal to identify crack damage in the grouting material.

[0080] Step 11: Conduct steel bar strain detection: Use optical fiber sensors to measure the strain data of the steel bars at various stages. Through the strain data and the constitutive relationship of the steel bars, the stress level of the steel bars can be obtained, and the stress state and health level of the steel bars can be determined.

[0081] The detection principle of the density of the grouting material is: stress wave propagation is applied to the detection of the density of the grouting material through the modern acoustic "time reversal" concept. One smart aggregate 12 is stimulated to generate a monitoring signal, and the other smart aggregate 12 receives the monitoring signal. At the same time, the received signal is inverted in the time domain and stimulated again to receive the reconstructed signal. The received signal is processed by waveform processing to obtain the normalized waveform of each signal, and the density of the grouting material is detected by comparing the difference between them. When the medium between the two "smart aggregates" has no defects such as voids and cracks that affect the density, the reconstructed signal is basically consistent with the original monitoring signal; if there is a defect between the two sensors, the reconstructed signal will be different from the original monitoring signal. For this detection method, in order to more clearly distinguish the difference between the reconstructed signal and the original signal, a pulse signal with peak fluctuations is selected. Since the attenuation of sound waves will increase with the increase of frequency when propagating in the grouting material, a lower frequency should be selected to increase the penetration ability of sound waves in the material. For the above reasons, the detection signal uses a pulse wave with five peaks with a frequency lower than 5kHz.

[0082] The detection principle of grouting material strength is as follows: According to the stress wave propagation theory, the propagation parameters (amplitude, wave velocity, etc.) of stress waves are closely related to the characteristics of the propagation medium. When the mechanical parameters of the propagation medium (such as elastic modulus, shear modulus, etc.) change, the signal received by the piezoelectric sensor, i.e., the intelligent aggregate 7, will change (amplitude attenuation, propagation time delay, etc.), and the change in the strength of the grouting material can be judged based on its change. The sleeve grouting material is mainly a high-strength composite material composed of slurry and fine aggregate. The biggest difference between it and concrete material is that there is no coarse aggregate such as stone in the sleeve grouting material. Based on this difference, when the sound wave propagates in the grouting material, when the frequency is low, the wavelength is long and much larger than the average diameter of the fine aggregate of the grouting material. The sound wave can bypass the aggregate during the propagation process, and the attenuation at this time is mainly absorption attenuation. According to the absorption attenuation Stokes-Kirchhoff formula, the absorption attenuation coefficient is not only related to the properties of the medium, but also to the frequency of the sound wave. The larger the frequency ω, the greater the attenuation. Since the sinusoidal periodic signal has the advantages of simple structure and easy post-processing, the monitoring signal can be selected as a low-frequency (100Hz-1kHz) sinusoidal periodic signal.

[0083] The monitoring principle of grouting cracks is: when the stress wave encounters damage such as cracks in the structure during the propagation of the grouting material, reflection and other phenomena will occur, resulting in the attenuation of the stress wave, which in turn causes the attenuation of the received signal energy. The signal amplitude in the time domain analysis is highly sensitive to crack damage, and as the damage increases, the amplitude attenuates more severely. The signals that are more sensitive to structural crack damage mainly include sinusoidal periodic signals, pulse signals, and swept frequency signals. Among them, the sinusoidal periodic signal has the advantages of simple structure and easy post-processing. The pulse signal has the advantages of small data storage and sensitivity to damage, but the propagation distance is short, and the stability and anti-interference are not as good as the sinusoidal periodic signal. Combining the pros and cons of various signals, the sinusoidal periodic signal can be selected as the monitoring signal. In terms of sensitivity, according to experimental research, high-frequency signals are more sensitive to minor damage, but the higher the frequency, the more the signal amplitude attenuates; in terms of propagation distance, generally when the frequency is 10kHz, the signal can propagate about 10 meters, and when the frequency reaches 100kHz, it can only propagate to 1 meter. After comprehensive consideration and a large number of experimental studies, the utility model determines the frequency range of the sweep signal to be 100Hz-10kHz, so that the signal has both strong vitality and good sensitivity to damage when propagating in the medium. The detection of cracks is the same as the principle of strength monitoring, using signal energy as a characteristic index to characterize structural damage, thereby improving the sensitivity of damage characterization.

[0084] The above-mentioned detection principles for the density, strength and cracks of the grouting material are all conventional technical means in this field. For the analysis and judgment of the subsequent detection data, reference can be made to the methods in the paper "Research on the Identification of Peeling Damage of CFRP Reinforced Concrete Structures Using PZT". The utility model only improves the structure of the sleeve, and does not improve the detection method. The detection method adopts the existing technology.

[0085] Regarding the specific structure of the utility model, it should be explained that the connection relationship between the various component modules adopted in the utility model is definite and feasible. Except for special instructions in the embodiments, the specific connection relationship can bring corresponding technical effects and solve the technical problems raised by the utility model without relying on the execution of corresponding software programs. The components, modules, models of specific components and the connection methods between each other appearing in the utility model, as well as the conventional use methods and expected technical effects brought about by the above-mentioned technical features, except for specific instructions, all belong to the disclosed contents in patents, journal articles, technical manuals, technical dictionaries, and textbooks that can be obtained by technical personnel in this field before the application date, or belong to the existing technologies such as conventional technologies and common knowledge in this field, and there is no need to elaborate, so that the technical solution provided in this case is clear, complete and feasible, and the corresponding physical products can be reproduced or obtained according to the technical means.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. An intelligent steel bar sleeve grouting lap joint, comprising a sleeve (3), one end of the sleeve (3) is provided with a grouting hole (4), and the other end of the sleeve (3) is provided with a grout outlet hole (5), characterized in that: The sleeve (3) is also provided with an intelligent aggregate hole (6) and an intelligent steel bar hole (7). Two parallel positioners (8) are fixed inside the sleeve (3), one of the positioners (8) is located outside the grouting hole (5), and the other positioner (8) is located outside the grouting hole (4). The two positioners (8) are respectively embedded with intelligent aggregates (12) for detecting the density, strength and crack signals of the grouting material. The two intelligent aggregates (12) are located on the same center line and are arranged opposite to each other. The wires of the two intelligent aggregates (12) pass through the two intelligent aggregate holes (6) and are connected to one end of two copper shafts (9). The copper shafts (9) are fixed outside the sleeve (3); Reserved intelligent steel bars (1) are respectively fixed to both ends of the sleeve (3) wall, and optical fiber sensors for monitoring stress and strain of the steel bars are arranged on the reserved intelligent steel bars (1).

2. The intelligent steel sleeve grouting lap joint according to claim 1, characterized in that: The grouting hole (4) and the grouting hole (5) are located on the same side of the sleeve (3).

3. The intelligent steel sleeve grouting lap joint according to claim 2 is characterized in that: The grouting hole (4) and the grouting hole (5) are located on the same center line.

4. The intelligent steel sleeve grouting lap joint according to claim 3 is characterized in that: The two positioners (8) are located on the same plane as the grouting hole (4) and the grouting hole (5).

5. An intelligent steel sleeve grouting lap joint according to any one of claims 1 to 4, characterized in that: The other end of the optical fiber sensor passes through the intelligent steel bar hole (7) and is connected to an external optical fiber modem, the optical fiber modem is connected to a data acquisition card (10) via a wire, the data acquisition card (10) is also connected to a display control terminal (11) via a wire, and the other ends of the two copper shafts (9) are respectively connected to the data acquisition card (10) via wires.

6. The intelligent steel sleeve grouting lap joint according to claim 5, characterized in that: The smart aggregate (12) is a piezoelectric smart aggregate, which is arranged in a circular ring shape and includes a piezoelectric ceramic sheet and a shielding wire. The piezoelectric ceramic sheet welded to the shielding wire is placed inside the circular ring. The upper and lower surfaces of the circular ring use epoxy resin as an outer packaging and waterproof layer. One end of the circular ring is provided with a circular notch for the shielding wire to be output.

7. The intelligent steel sleeve grouting lap joint according to claim 6, characterized in that: The positioner (8) is made of a steel plate, a circular hole is cut in the middle of the steel plate, and the smart aggregate (12) is adhered to the circular hole.

8. The intelligent steel sleeve grouting lap joint according to claim 6 or 7, characterized in that: The reserved smart steel bar (1) comprises a ribbed steel bar (101), a groove for fixing the optical fiber sensor is formed on the ribbed steel bar (101), a part of the optical fiber sensor is fixed in the groove of the ribbed steel bar (101), and another part of the optical fiber sensor passes through the smart steel bar hole (7) and extends out of the sleeve (3).

9. The intelligent steel sleeve grouting lap joint according to claim 8, characterized in that: The optical fiber sensor adopts a fully distributed optical fiber sensor (102) for measuring the strain of the entire length of the steel bar or a point optical fiber sensor (103) for measuring the strain at both ends and in the middle of the steel bar.

10. The intelligent steel sleeve grouting lap joint according to claim 9, characterized in that: The data acquisition card (10) collects the density data of the grouting material by stimulating the intelligent aggregate (12) to transmit and receive five peak pulse wave signals with a frequency lower than 5 kHz; The data acquisition card (10) collects the grouting material strength data by stimulating the intelligent aggregate (12) to transmit and receive a sinusoidal periodic signal with a frequency of 100 Hz to 1 kHz; The data acquisition card (10) collects the crack data of the grouting material by stimulating the intelligent aggregate (12) to transmit and receive a sinusoidal periodic signal with a frequency of 100 Hz-10 kHz.

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