Self-sensing prestressed high-strength steel strand mesh-bfrc reinforced reinforced concrete beam structure

Abstract

The application relates to the technical field of building structure reinforcement, and discloses a self-sensing prestressed high-strength steel strand net-BFRC reinforced reinforced concrete beam structure, which comprises a reinforced concrete beam to be reinforced, a horizontal high-strength steel strand internally integrated with an optical fiber sensing unit, is fixed at both ends of the beam through an anchoring assembly and prestress is applied; vertical high-strength steel strands are connected with the horizontal high-strength steel strands through cross buckles to form a steel strand net; and basalt fiber concrete is cast on the outside of the steel strand net to form a reinforcing layer. The horizontal high-strength steel strand integrated with the optical fiber sensing unit can monitor the steel strand strain and prestress change in real time, and realizes self-sensing of the service state of the reinforced structure. The prestressed high-strength steel strand net, the BFRC reinforcing layer and the optical fiber sensing technology are organically combined, long-term monitoring of the prestress state and structure stress information is realized while the bearing capacity, crack resistance and durability are improved, and the application has the advantages of simple structure, convenient construction, high integration degree of reinforcement and monitoring and the like.

Description

Technical Field

[0001] This invention belongs to the field of building structure reinforcement technology, specifically a self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure. Background Technology

[0002] During long-term service, reinforced concrete beams are prone to decreased load-bearing capacity and durability degradation due to factors such as increased load, environmental erosion, and material aging. Strengthening existing beams using prestressed high-strength steel strand mesh combined with an external concrete layer is a widely used technical solution in current engineering applications.

[0003] However, this reinforcement system faces a unique technical challenge in actual operation. The effectiveness of the external prestressing scheme rests on a core premise: the prestress value within the steel strands must always be maintained within the designed effective range. However, during long-term service, the steel strands inevitably experience stress relaxation, and the reinforced concrete layer also undergoes shrinkage and creep. The combined effect of these two factors leads to unpredictable and continuous attenuation of the prestress. Once the prestress is excessively lost, the reinforcement effect will be significantly reduced, and it may even cause brittle failure of the reinforced structure without any obvious warning signs, which will be almost undetectable from the outside.

[0004] To address this issue, the industry has introduced fiber optic sensing technology for internal stress monitoring. However, when fiber optic sensors are embedded inside prestressed steel strands and subsequently poured into high-fiber-content basalt fiber reinforced concrete (BFRC), a previously unrecognized physical contradiction arises: the helically embedded fiber optic cable between the strands experiences both compression and tension during prestressing, resulting in irregular initial strain. Furthermore, during subsequent BFRC pouring and vibration, the high-stiffness basalt fibers, flowing with the slurry, cause micro-collisions and localized compression on the fiber optic sheath, further introducing random, discrete initial strain noise. These two effects superimpose on the fiber optic sensor, resulting in an irregular, unreproducible initial offset in the sensing signal. This offset is on the same order of magnitude in signal amplitude as the actual micro-strain caused by prestress attenuation, making it difficult to effectively distinguish between "signal drift" and "true prestress loss" during long-term monitoring, severely impacting the accuracy of prestress state assessment.

[0005] Because this initial strain uncertainty arises randomly from the minute differences in the BFRC casting state and the tensioning state of the steel strands in each beam, conventional calibration or filtering methods are difficult to effectively eliminate. Therefore, how to achieve long-term stable monitoring of the prestressing state of the steel strands under such combined construction interferences constitutes a unique technical challenge in this field. Summary of the Invention

[0006] To address the problems in existing reinforced concrete beam reinforcement technologies, such as the difficulty in real-time monitoring of prestressed state, insufficient crack resistance of the reinforcement layer, and the separation of reinforcement structure from health monitoring functions, this invention provides a self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure. This invention organically combines fiber optic sensing technology, prestressed high-strength steel strand mesh reinforcement technology, and basalt fiber reinforced concrete (BFRC) reinforcement technology to achieve the integration of improved load-bearing capacity and real-time sensing of service status of reinforced concrete beams.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure, comprising a reinforced concrete beam to be reinforced, horizontal high-strength steel strands, vertical high-strength steel strands, and a BFRC reinforcement layer; The horizontal high-strength steel strand integrates an optical fiber sensing unit. The horizontal high-strength steel strand is arranged along the beam length direction of the reinforced concrete beam to be reinforced in the tension area at the bottom of the beam and is fixed to both ends of the reinforced concrete beam to be reinforced by anchoring components. The horizontal high-strength steel strand is prestressed. The vertical high-strength steel strands are arranged along the beam width of the reinforced concrete beam to be reinforced, and are connected and fixed to the horizontal high-strength steel strands by cross buckles to form a steel strand net. The BFRC reinforcement layer is poured on the outside of the bottom of the reinforced concrete beam to be reinforced, and the steel strand mesh is wrapped inside it; The anchoring assembly includes angle steel fixedly installed at the bottom of both ends of the reinforced concrete beam to be reinforced, and high-strength steel strand anchoring slip bolts and extended hexagonal nuts passing through the angle steel. The end of the horizontal high-strength steel strand passes through the high-strength steel strand anchoring slip bolt and is anchored into a closed loop. The extended hexagonal nut fixes the high-strength steel strand anchoring slip bolt to the outside of the angle steel.

[0008] Preferably, the optical fiber sensing unit includes an optical fiber, a single strand of steel wire, and an optical fiber protective sleeve, wherein the optical fiber is embedded inside the single strand of steel wire, and the optical fiber protective sleeve is fitted over the outside of the optical fiber. The optical fiber is embedded in a spiral shape between the strands of the single-strand steel strand, and the optical fiber protective sleeve is a high-toughness plastic sheath used to protect the optical fiber from tensile damage during prestressing tensioning.

[0009] Preferably, the beam end of the reinforced concrete beam to be reinforced is provided with an optical fiber outlet and a beam end monitoring box, and the optical fiber is led out through the optical fiber outlet and connected to the beam end monitoring box. A sealing ring is provided at the optical fiber outlet to protect the optical fiber from erosion by concrete slurry during the BFRC reinforcement layer pouring process.

[0010] Preferably, the angle steel is an L30×50×6 type angle steel, and the angle steel is fixed to the bottom of both ends of the reinforced concrete beam to be reinforced by inverted conical chemical bolts and inverted conical chemical bolt nuts.

[0011] Preferably, the steel strand mesh is fixed to the bottom of the reinforced concrete beam to be reinforced by M6 straight steel strand mesh anchor bolts.

[0012] Preferably, the raw materials of the BFRC reinforcement layer include cement, silica fume, fly ash, sand, water and basalt fiber, and the mixing ratio is cement:fly ash:silica fume:sand:water:basalt fiber = 1:0.27:0.08:0.54:0.41:0.04.

[0013] Preferably, the cement is ordinary Portland cement PO 42.5, and the dosage is 380-500 kg / m³. 3 ; The amount of silica fume used is 5% to 10% of the total amount of cementitious materials; The amount of fly ash used is 20% to 30% of the total amount of cementitious materials; The water-to-binder ratio is 0.30–0.40; The basalt fiber content is 0.6% to 1.4%; The sand is natural river sand with a particle size of no more than 2.5 mm and a natural mud content of less than 5%.

[0014] Preferably, the horizontal high-strength steel strand is prestressed by a torque wrench and is in a pre-tensioned working state.

[0015] This invention provides a construction method for constructing a self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure, comprising the following steps: S1. Surface treatment of the original beam: The surface of the tension area at the bottom of the reinforced concrete beam to be reinforced is roughened to form a rough interface. Loose concrete is removed with a steel brush and surface dust is removed with a high-pressure water gun. S2. Anchoring component installation: Drill holes at the design position at the bottom of the reinforced concrete beam to be reinforced, and insert inverted conical chemical bolts. After the chemical bolts reach the design strength, install angle steel at both ends of the beam and fix the angle steel to the reinforced concrete beam with inverted conical chemical bolt nuts. S3. Installation and tensioning of prestressed high-strength steel strands: Insert the horizontal high-strength steel strands into the anchor bolts of the high-strength steel strands, and use the pressure ring to anchor the end of the steel strands into a closed loop. Pass the anchor bolts of the high-strength steel strands through the angle steel and fix them to the outside of the angle steel with extended hexagonal nuts. Anchor the other end of the steel strands in the same way. Apply prestress to the horizontal high-strength steel strands according to the target torque value using a torque wrench. S4. Formation of steel strand mesh: Vertical high-strength steel strands are arranged at the designed spacing and connected and fixed to horizontal high-strength steel strands through cross buckles to form a steel strand mesh structure. S5, BFRC reinforcement layer construction: After the steel strand mesh is anchored, the template is installed. Before pouring, the bottom interface of the beam is rinsed to keep it clean and moist. Then, basalt fiber concrete is poured to form the BFRC reinforcement layer (3). The plate vibrator is used to compact it, and after smoothing, it is cured. S6. Fiber Optic Lead-out and Monitoring System Connection: The fiber optic cable is led out through the fiber optic outlet and connected to the beam end monitoring box. The fiber optic sensing unit collects the strain signal of the steel strand in real time through the fiber optic cable. The beam end monitoring box has a built-in signal demodulation module that converts the strain signal into a prestress value, thereby realizing long-term real-time monitoring of the service status of the reinforced structure.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) In view of the unique technical problem that the irregular initial strain noise generated by the random micro-collision and local extrusion of the basalt fiber on the embedded optical fiber protective sleeve during the BFRC casting and vibration process of the prestressed steel strand, it is difficult to effectively distinguish the signal drift and the actual prestress loss in long-term monitoring, the present invention uses the structural design of embedding the optical fiber in a spiral shape between the strands of the steel strand and configuring a high-toughness plastic protective sleeve. By utilizing the absorption and dispersion of random micro-collision energy by the protective sleeve during the BFRC casting and vibration process, these construction disturbance signals are transformed into transient signals that are evenly distributed in space and decay rapidly in time. This avoids the large single-point offset caused by local concentrated extrusion and significantly reduces the interference level of construction factors on the initial measurement value from the source.

[0017] (2) In view of the problem that the fiber output has irregular initial strain due to the combined effect of compression and stretching of the steel strands on the embedded optical fiber during the prestressing process, the present invention designs the pitch of the spiral winding of the optical fiber to absorb a certain amount of tensile deformation and avoid directly bearing all the axial strain of the steel strand. When the steel strand is prestressed, the spiral optical fiber is gradually tightened instead of bearing pure axial tension, so that the initial strain output of the optical fiber tends to be smooth, a stable and reliable measurement benchmark is established, and the comparability of long-term prestress attenuation monitoring data is guaranteed.

[0018] (3) In view of the problem that the long-term prestress state assessment is inaccurate due to excessive initial interference in the construction of the fiber optic sensing signal in the existing reinforcement scheme, the present invention uses an adjustable anchoring assembly composed of anchoring live bolts and extended hexagonal nuts to achieve precise control of the anchoring force while applying prestress, so that the two ends of the steel strand are symmetrically and synchronously stressed, avoiding the interference of additional torsional stress caused by uneven stress at the anchoring end on the spiral fiber optic signal output, and ensuring the measurement consistency of the fiber optic sensor throughout its entire life cycle.

[0019] (4) In view of the problem that the uneven distribution of basalt fibers inside the BFRC reinforcement layer may cause regional stiffness differences and thus lead to uneven stress on local optical fibers, this invention improves the uniformity of fiber dispersion in the matrix by the synergistic filling effect of silica fume and fly ash in the BFRC mix ratio and the optimized doping design of basalt fibers, so that the stiffness distribution inside the BFRC reinforcement layer tends to be uniform, providing a monitoring environment with balanced stress in all directions for embedded optical fibers, and further reducing the introduction of structural initial noise.

[0020] (5) The present invention uses basalt fiber concrete (BFRC) as the external reinforcement layer of steel strand mesh. By utilizing the good tensile properties and crack control ability of basalt fiber, the crack resistance and ductility of the reinforcement layer are improved, the risk of cracking and interface damage of the reinforcement layer is reduced, the synergistic stress-bearing capacity between the high-strength steel strand mesh and the original reinforced concrete beam is enhanced, and the durability of the reinforced structure is improved.

[0021] (6) This invention integrates fiber optic sensors with prestressed high-strength steel strand mesh. Through fiber optic sensors, the strain changes of steel strands under tension, load and long-term service are obtained in real time, so as to realize the perception of the prestress state of steel strands, and can detect prestress loss and structural damage in a timely manner, thereby improving the ability to assess the service status of reinforced structures.

[0022] (7) By setting up an optical fiber lead-out structure and protective components, the present invention enables the optical fiber sensor to remain stable during the application of prestress, anchoring and fixing and concrete pouring, avoiding the problems of easy damage to the sensing element and difficulty in long-term deployment in traditional monitoring methods, and improving the reliability of the monitoring system.

[0023] (8) This invention combines the reinforcement structure with the health monitoring function, which improves the load-bearing performance of reinforced concrete beams and realizes long-term monitoring of the internal stress state. It reduces the need for additional monitoring equipment to be installed in traditional reinforcement structures and has the advantages of structural integration, intelligence and high engineering application value. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0025] In the attached diagram: Figure 1 Schematic diagram of the elevation of a reinforced concrete beam structure reinforced with self-sensing prestressed high-strength steel strand mesh-BFRC; Figure 2 Schematic diagram of the installation structure for self-sensing prestressed high-strength steel strand mesh; Figure 3 This is a schematic diagram of an intelligent steel strand structure; Figure 4 This is a schematic diagram of the beam end anchorage and fiber optic cable lead-out structure.

[0026] In the diagram: 1-Reinforced concrete beam to be reinforced, 2-Horizontal high-strength steel strand, 3-BFRC reinforcement layer, 4-Vertical high-strength steel strand, 5-Cross buckle, 6-M6 straight steel strand mesh anchor bolt, 7-L30×50×6 angle steel, 8-Extended hexagonal nut, 9-High-strength steel strand anchor knot bolt, 10-Inverted conical chemical bolt, 11-Inverted conical chemical bolt nut, 12-Fiber optic cable, 13-Single strand steel strand, 14-Fiber optic cable protective sleeve, 15-Fiber optic cable outlet, 16-Horizontal high-strength steel strand joint, 18-Beam end monitoring box. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] Example 1, as Figures 1-4 As shown, this embodiment provides a self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure, including a reinforced concrete beam to be reinforced 1, horizontal high-strength steel strands 2, vertical high-strength steel strands 4, and BFRC reinforcement layer 3. The horizontal high-strength steel strand 2 integrates an optical fiber sensing unit, which collects information on the strain and prestress changes of the steel strand in real time, enabling real-time monitoring of the service status of the reinforced structure. The horizontal high-strength steel strand 2 is arranged along the beam length of the reinforced concrete beam 1 to be reinforced in the tension area at the bottom of the beam and is fixed to both ends of the reinforced concrete beam 1 to be reinforced by anchoring components. The horizontal high-strength steel strand 2 is prestressed. The vertical high-strength steel strand 4 is arranged along the beam width direction of the reinforced concrete beam 1 to be reinforced, and is connected and fixed to the horizontal high-strength steel strand 2 by cross buckles 5 to form a stable steel strand net. The BFRC reinforcement layer 3 is poured on the outside of the bottom of the reinforced concrete beam 1 to be reinforced, and the steel strand mesh is wrapped inside. BFRC has good crack resistance, toughness and durability, which can effectively inhibit crack propagation and improve the synergistic working performance between the steel strand mesh and the original beam. It is particularly suitable for corrosive environments, humid environments and other engineering reinforcement scenarios with high durability requirements. The anchoring assembly includes angle steel 7 fixedly installed at the bottom of both ends of the reinforced concrete beam 1 to be reinforced, and high-strength steel strand anchoring bolts 9 and extended hexagonal nuts 8 passing through the angle steel 7. The end of the horizontal high-strength steel strand 2 passes through the high-strength steel strand anchoring bolt 9 and is anchored into a closed loop. The extended hexagonal nut 8 fixes the high-strength steel strand anchoring bolt 9 to the outside of the angle steel 7.

[0029] Advantageously, the optical fiber sensing unit includes an optical fiber 12, a single strand of steel wire 13, and an optical fiber protective sleeve 14, wherein the optical fiber 12 is embedded inside the single strand of steel wire 13, and the optical fiber protective sleeve 14 is sleeved on the outside of the optical fiber 12. The optical fiber 12 is embedded in a spiral shape between the strands of the single-strand steel strand 13. The optical fiber protective sleeve 14 is a high-toughness plastic sheath used to protect the optical fiber 12 from tensile damage during the prestressing tensioning process. The optical fiber sensing unit collects the strain signal of the steel strand in real time through the optical fiber. The strain-prestress relationship curve obtained by the calibration experiment converts the strain signal into the prestress value, thereby realizing the quantitative monitoring of the prestress state of the steel strand. The optical fiber 12 is spirally embedded between the strands of the single-strand steel strand 13. During prestressing of the steel strand, the spirally wound optical fiber 12 gradually reduces its winding radius as the strands tighten. In this process, the optical fiber 12 mainly bears bending stress rather than pure axial tensile stress, avoiding signal saturation or excessive initial offset caused by tension stress concentration. The optical fiber protective sleeve 14 is a high-toughness plastic sheath. During BFRC pouring and vibration, the random local collisions caused by basalt fibers in the concrete slurry to the optical fiber protective sleeve 14 are effectively buffered and dispersed by the high-toughness sheath, so that the transient interference signals introduced by construction are evenly distributed in space and rapidly attenuated in time, ensuring the stability and accuracy of the output signal of the optical fiber 12 after construction.

[0030] Advantageously, the beam end of the reinforced concrete beam 1 to be reinforced is provided with an optical fiber outlet 15 and a beam end monitoring box 17, and the optical fiber 12 is led out through the optical fiber outlet 15 and connected to the beam end monitoring box 17. A sealing ring is provided at the optical fiber outlet 15 to protect the optical fiber 12 from erosion by concrete slurry during the pouring of the BFRC reinforcement layer 3.

[0031] Advantageously, the angle steel 7 is an L30×50×6 type angle steel, and the angle steel 7 is fixed to the bottom of both ends of the reinforced concrete beam 1 to be reinforced by inverted conical chemical bolts 10 and inverted conical chemical bolt nuts 11.

[0032] Beneficially, the steel strand mesh is fixed to the bottom of the reinforced concrete beam 1 to be reinforced by M6 straight steel strand mesh anchor bolts 6, so as to enhance the connection performance between the steel strand mesh and the original structure and improve the overall cooperative stress-bearing capacity of the reinforcement layer and the original beam.

[0033] Advantageously, the raw materials of the BFRC reinforcement layer 3 include cement, silica fume, fly ash, sand, water and basalt fiber, and the mixing ratio is cement:fly ash:silica fume:sand:water:basalt fiber = 1:0.27:0.08:0.54:0.41:0.04.

[0034] Advantageously, the cement is ordinary Portland cement PO 42.5, with a dosage of 380-500 kg / m³. 3 The dosage must meet the concrete strength requirements and must work synergistically with mineral admixtures. The amount of silica fume used is 5%-10% of the total amount of cementitious material (i.e., 20-50 kg / m³). 3 ); Silica fume can fill pores and improve density, but the amount of silica fume should not exceed 10% to avoid loss of fluidity; The amount of fly ash used is 20%-30% of the total amount of cementitious materials (i.e., 80-150 kg / m³). 3 The fly ash replacement rate shall not exceed 30% to balance early strength and durability. The water-cement ratio is 0.30-0.40; a low water-cement ratio (<0.35) can improve strength, but it needs to be combined with a water-reducing agent to ensure fiber dispersibility; the water-cement ratio of fiber-reinforced concrete should not exceed 0.45. The basalt fiber content is between 0.6% and 1.4%, and the total fiber content should be controlled below 2.5% to avoid poor concrete fluidity due to excessive fiber content. The sand is natural river sand with a particle size of no more than 2.5 mm and a natural mud content of less than 5%.

[0035] Existing reinforcement systems typically use ordinary mortar or polymer mortar as the external protective material for steel strand meshes. Their crack resistance and ductility are limited, making them prone to crack propagation and interface damage, thus affecting the synergistic performance between the steel strands and the matrix material. This invention employs basalt fiber reinforced concrete. Utilizing the excellent mechanical properties of basalt fibers, the fibers effectively inhibit crack development through bridging and reinforcement. Basalt fibers also possess excellent durability and protective capabilities, significantly enhancing the long-term service performance of structures in harsh environments.

[0036] Furthermore, existing prestressed steel strand mesh reinforcement structures typically only focus on the reinforcement effect, lacking real-time monitoring of the actual stress state of the steel strands and the prestress loss. During long-term service, due to factors such as material creep and shrinkage, environmental effects, and changes in anchoring performance, the prestress of the steel strands may attenuate, leading to a reduction in the reinforcement effect. However, existing technologies struggle to obtain timely information on internal stress changes. This invention uses fiber optic sensors to acquire real-time strain changes in the steel strands during tensioning, loading, and long-term service, enabling the perception of the prestress state of the steel strands. This allows for timely detection of prestress loss and structural damage, improving the ability to assess the service status of reinforced structures.

[0037] Advantageously, the horizontal high-strength steel strand 2 is prestressed by a torque wrench and is in a pre-tensioned working state.

[0038] Example 2: This example provides a construction method for constructing a self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure, the steps of which include: S1. Surface treatment of the original beam: The surface of the tension area at the bottom of the reinforced concrete beam 1 to be reinforced is roughened to form a rough interface. Loose concrete is removed with a steel brush and surface dust is removed with a high-pressure water gun to improve the bonding performance between the new and old materials. S2. Anchoring component installation: Drill holes at the design position at the bottom of the reinforced concrete beam 1 to be reinforced, and insert inverted conical chemical bolts 10. After the chemical bolts reach the design strength, install angle steel 7 at both ends of the beam and fix the angle steel 7 to the reinforced concrete beam 1 with inverted conical chemical bolt nuts 11. S3. Installation and tensioning of prestressed high-strength steel strands: Insert the horizontal high-strength steel strand 2 into the high-strength steel strand anchor bolt 9, and use the pressure ring to anchor the end of the steel strand into a closed loop. Pass the high-strength steel strand anchor bolt 9 through the angle steel 7, and use the extended hexagonal nut 8 to fix it to the outside of the angle steel 7. Anchor the other end of the steel strand in the same way. Use a torque wrench to apply prestress to the horizontal high-strength steel strand 2 according to the target torque value, so that the steel strand is in the pre-tensioned working state. S4. Formation of steel strand mesh: Vertical high-strength steel strands 4 are arranged at the designed intervals and connected and fixed to horizontal high-strength steel strands 2 by cross buckles 5 to form a steel strand mesh structure. Among them, the horizontal high-strength steel strand 2 is the main load-bearing component, and also integrates fiber optic sensing function to monitor the strain and prestress changes of the steel strand in real time; the vertical high-strength steel strand 4 is mainly used to form a mesh structure and improve the overall cooperative load-bearing performance.

[0039] The steel strand mesh is fixed to the bottom of the reinforced concrete beam 1 to be reinforced by M6 straight steel strand mesh anchor bolts 6 to enhance the connection performance between the steel strand mesh and the original structure. S5, BFRC reinforcement layer construction: After the steel strand mesh is anchored, the template is installed according to the design reinforcement layer thickness. Before pouring, the bottom interface of the beam is rinsed again with a high-pressure water gun to keep it clean and moist, so as to enhance the bonding effect between the BFRC reinforcement layer and the original concrete beam. Then, basalt fiber concrete is poured to form BFRC reinforcement layer 3. During the pouring process, a plate vibrator is used to compact it to reduce internal voids and improve density. Finally, the surface is smoothed and cured. S6. Fiber Optic Lead-out and Monitoring System Connection: A fiber optic lead-out outlet 15 and a beam end monitoring box 17 are installed at the beam end of the reinforced concrete beam 1 to be reinforced. A sealing ring is installed at the fiber optic lead-out outlet 15 to protect the fiber optic cable 12 from erosion by concrete slurry during the pouring of the BFRC reinforcement layer 3. After the fiber optic cable 12 is led out through the fiber optic lead-out outlet 15, it is connected to the beam end monitoring box 17. The fiber optic sensing unit collects the strain signal of the steel strand in real time through the fiber optic cable 12. The beam end monitoring box 17 has a built-in signal demodulation module to convert the strain signal into a prestress value, realizing long-term real-time monitoring of the service status of the reinforced structure.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure, characterized in that: Includes reinforced concrete beams to be reinforced (1), horizontal high-strength steel strands (2), vertical high-strength steel strands (4), and BFRC reinforcement layer (3); The horizontal high-strength steel strand (2) integrates an optical fiber sensing unit. The horizontal high-strength steel strand (2) is arranged along the beam length direction of the reinforced concrete beam (1) to be reinforced in the tension area at the bottom of the beam and is fixed to both ends of the reinforced concrete beam (1) to be reinforced by an anchoring assembly. The horizontal high-strength steel strand (2) is prestressed. The vertical high-strength steel strand (4) is arranged along the beam width direction of the reinforced concrete beam (1) to be reinforced, and is connected and fixed to the horizontal high-strength steel strand (2) by cross buckles (5) to form a steel strand net. The BFRC reinforcement layer (3) is poured on the outside of the bottom of the reinforced concrete beam (1) to be reinforced, and the steel strand mesh is wrapped inside; The anchoring assembly includes angle steel (7) fixedly installed at the bottom of both ends of the reinforced concrete beam (1) to be reinforced, and high-strength steel strand anchoring slip bolts (9) and extended hexagonal nuts (8) passing through the angle steel (7). The end of the horizontal high-strength steel strand (2) passes through the high-strength steel strand anchoring slip bolts (9) and is anchored into a closed loop. The extended hexagonal nuts (8) fix the high-strength steel strand anchoring slip bolts (9) to the outside of the angle steel (7).

2. The self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure according to claim 1, characterized in that: The optical fiber sensing unit includes an optical fiber (12), a single strand of steel wire (13), and an optical fiber protective sleeve (14). The optical fiber (12) is embedded inside the single strand of steel wire (13), and the optical fiber protective sleeve (14) is sleeved on the outside of the optical fiber (12). The optical fiber (12) is embedded in a spiral shape between the strands of the single-strand steel strand (13), and the optical fiber protective sleeve (14) is a high-toughness plastic sheath used to protect the optical fiber (12) from tensile damage during the prestressing tensioning process.

3. The self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure according to claim 2, characterized in that: The beam end of the reinforced concrete beam (1) to be reinforced is provided with an optical fiber outlet (15) and a beam end monitoring box (17). The optical fiber (12) is led out through the optical fiber outlet (15) and connected to the beam end monitoring box (17). A sealing ring is provided at the optical fiber outlet (15) to protect the optical fiber (12) from erosion by concrete slurry during the pouring of the BFRC reinforcement layer (3).

4. The self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure according to claim 3, characterized in that: The angle steel (7) is an L30×50×6 type angle steel, and the angle steel (7) is fixed to the bottom of both ends of the reinforced concrete beam (1) to be reinforced by inverted conical chemical bolts (10) and inverted conical chemical bolt nuts (11).

5. The self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure according to claim 4, characterized in that: The steel strand mesh is fixed to the bottom of the reinforced concrete beam (1) to be reinforced by M6 straight steel strand mesh anchor bolts (6).

6. The self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure according to claim 5, characterized in that: The raw materials of the BFRC reinforcement layer (3) include cement, silica fume, fly ash, sand, water and basalt fiber, and the mixing ratio is cement: fly ash: silica fume: sand: water: basalt fiber = 1: 0.27: 0.08: 0.54: 0.41: 0.

04.

7. The self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure according to claim 6, characterized in that: The cement is ordinary Portland cement PO 42.5, with a dosage of 380–500 kg / m³. 3 ; The amount of silica fume used is 5% to 10% of the total amount of cementitious materials; The amount of fly ash used is 20% to 30% of the total amount of cementitious materials; The water-to-binder ratio is 0.30–0.40; The basalt fiber content is 0.6% to 1.4%; The sand is natural river sand with a particle size of no more than 2.5 mm and a natural mud content of less than 5%.

8. The self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure according to claim 7, characterized in that: The horizontal high-strength steel strand (2) is prestressed by a torque wrench and is in a pre-tensioned working state.

9. A construction method for constructing a self-sensing prestressed high-strength steel strand mesh-BFRC reinforced reinforced concrete beam structure as described in claim 8, characterized in that: step include: S1. Surface treatment of the original beam: The surface of the bottom tension area of ​​the reinforced concrete beam (1) to be reinforced is roughened to form a rough interface on the original beam surface. Loose concrete is removed by steel brush and surface dust is removed by high pressure water gun. S2. Installation of anchoring components: Drill holes at the bottom of the reinforced concrete beam (1) to be reinforced according to the design position, and insert inverted conical chemical bolts (10). After the chemical bolts reach the design strength, install angle steel (7) at both ends of the beam, and fix the angle steel (7) to the reinforced concrete beam (1) by inverted conical chemical bolt nuts (11). S3. Installation and tensioning of prestressed high-strength steel strand: Insert the horizontal high-strength steel strand (2) into the high-strength steel strand anchor bolt (9), and use the pressure ring to anchor the end of the steel strand into a closed loop. Pass the high-strength steel strand anchor bolt (9) through the angle steel (7) and fix it to the outside of the angle steel (7) with the extended hexagonal nut (8). Anchor the other end of the steel strand in the same way. Apply prestress to the horizontal high-strength steel strand (2) according to the target torque value using a torque wrench. S4. Formation of steel strand mesh: The vertical high-strength steel strands (4) are arranged according to the design spacing and connected and fixed to the horizontal high-strength steel strands (2) through cross buckles (5) to form a steel strand mesh structure. S5, BFRC reinforcement layer construction: After the steel strand mesh is anchored, the template is installed. Before pouring, the bottom interface of the beam is rinsed to keep it clean and moist. Then, basalt fiber concrete is poured to form the BFRC reinforcement layer (3). The plate vibrator is used to compact it, and after smoothing, it is cured. S6. Fiber optic cable lead-out and monitoring system connection: After the fiber optic cable (12) is led out through the fiber optic cable lead-out port (15), it is connected to the beam end monitoring box (17). The fiber optic sensing unit collects the strain signal of the steel strand in real time through the fiber optic cable (12). The beam end monitoring box (17) has a built-in signal demodulation module to convert the strain signal into a prestress value, so as to realize long-term real-time monitoring of the service status of the reinforced structure.

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