Channel bridge reinforcing construction method

Abstract

The invention belongs to the technical field of channel bridge reinforcing construction methods, and particularly relates to a channel bridge reinforcing construction method which comprises the following steps: S1, channel bridge damage detection and positioning; s2, pre-treating a base layer at the damaged part of the channel bridge; s3, carrying out layered gradient reinforcement on the damaged part of the channel bridge; s4, performing intelligent stress monitoring on the damaged part of the channel bridge; s5, self-adaptive maintenance of the damaged part of the channel bridge, according to the overall structure provided by the embodiment of the invention, a collaborative reinforcement technology of accurate damage positioning, layered gradient reinforcement, intelligent stress monitoring and self-adaptive maintenance is provided, and the reinforcement process is accurate and intelligent through a damage grade evaluation formula and a maintenance parameter dynamic adjustment formula; the ultrasonic-assisted bonding and prestress tensioning technology is adopted, the bonding compactness of the CFRP cloth and the base layer is improved, stress concentration is avoided, the structural bearing capacity is improved by 30% or above, and the service life of the reinforcing layer is prolonged to 25 years or above; the layered gradient reinforcing technology simplifies the construction process, and the construction period is shortened by 20%.

Description

Technical Field

[0001] This application relates to the field of bridge reinforcement technology, and in particular to a bridge reinforcement construction method. Background Technology

[0002] As a crucial component of transportation infrastructure, underpasses bear the weight of vehicles and environmental erosion over extended periods, making them prone to problems such as concrete cracking, steel reinforcement corrosion, and reduced structural load-bearing capacity, severely impacting traffic safety. Traditional reinforcement methods for underpasses mainly include steel plate bonding, cross-section enlargement, and concrete encasing. However, these methods have several drawbacks: steel plate bonding is prone to corrosion and poor adhesion, and also results in significant self-weight; cross-section enlargement has a long construction period and substantial traffic disruption; and concrete encasing leads to poor overall integrity and significant stress concentration.

[0003] Carbon fiber reinforced polymer (CFRP) composites possess advantages such as high strength, lightweight, corrosion resistance, and convenient construction, and have been gradually applied in the field of bridge reinforcement. However, existing CFRP reinforcement methods still have the following shortcomings: First, the accuracy of damage detection before reinforcement is low, making it impossible to accurately locate key reinforcement areas; second, the CFRP fabric does not bond tightly to the base layer, easily generating air bubbles and affecting the reinforcement effect; third, there is a lack of a real-time stress monitoring mechanism, resulting in uneven stress distribution during reinforcement and easily leading to secondary damage; fourth, the curing parameters are fixed, failing to consider the impact of environmental factors on the curing of the reinforcement layer, leading to a shortened service life of the reinforcement layer. Therefore, developing a bridge reinforcement construction method that combines precision, collaboration, and intelligence has become an urgent technical problem to be solved. This invention proposes a bridge reinforcement construction method. Summary of the Invention

[0004] This application provides a method for reinforcing underpasses to solve the problems mentioned above.

[0005] This application provides a method for reinforcing a bridge, including the following steps: S1. Damage detection and localization of the channel bridge; S2. Pre-treatment of the base layer at the damaged section of the passageway bridge; S3. Layered gradient reinforcement at the damaged section of the channel bridge; S4. Intelligent stress monitoring at damaged locations on the tunnel bridge; S5. Adaptive maintenance of damaged sections of the tunnel bridge.

[0006] Preferably, the damage detection and location of the underpass bridge adopts a combination of ultrasonic tomography technology and fiber optic grating sensor array to conduct a comprehensive inspection of the main structure of the underpass bridge, obtain data on crack width, depth, degree of steel corrosion and concrete strength distribution, calculate the structural damage level D, and determine the key areas for reinforcement.

[0007] Preferably, the formula for calculating the structural damage level D is:

[0008] in: , , These are the weighting coefficients for crack width, damage depth, and steel corrosion rate, respectively. To measure the crack width, To allow for crack width, To measure the depth of damage, For structural design thickness, To measure the corrosion rate of the reinforcing steel, To allow for a certain corrosion rate, when D ≥ 0.6, the area is considered severely damaged and requires priority reinforcement.

[0009] Preferably, the pretreatment of the base layer at the damaged section of the passage bridge includes surface grinding and dust removal of the reinforced area, rinsing with a high-pressure water gun and air drying, and for areas with crack width > 0.2 mm, injecting modified epoxy resin grout, with the grouting pressure controlled at 0.3-0.5 MPa and the curing time ≥ 24 h.

[0010] Preferably, the layered gradient reinforcement at the damaged area of ​​the channel bridge consists of three layers; First layer: Apply primer to the base surface of the damaged area of ​​the channel bridge using an ultrasonic-assisted application process with an ultrasonic frequency of 20-30kHz and a coating thickness of 0.2-0.3mm. Curing time is 8-12 hours. Second layer: CFRP cloth is laid on the adhesive surface, and a pre-tensioning force of 5-8MPa is applied using a pre-stressing tensioning device at a tensioning speed of 0.5mm / min. At the same time, adhesive is applied again to the CFRP cloth coating surface to ensure that the CFRP cloth is tightly bonded to the base layer. The adhesive coating thickness is 0.3-0.5mm. Third layer: Based on the structural damage level, lay an additional layer of CFRP cloth in the severely damaged area, and repeat the steps of laying the second layer of CFRP cloth and applying adhesive to form a gradient reinforcement structure of primer, double layer of CFRP cloth and topcoat. The CFRP fabric has a tensile strength ≥4000MPa, an elastic modulus ≥230GPa, a thickness of 0.15-0.2mm, and a width of 500-1000mm.

[0011] Preferably, the intelligent stress monitoring of the damaged area of ​​the bridge includes embedding fiber optic stress sensors during the CFRP fabric laying process. The sensor spacing is 500-800mm to monitor the stress change of the reinforcement layer in real time. The monitoring data is sent to the background system through a data transmission module. When the monitored stress value exceeds 10% of the design value, the prestressing tensioning parameters are automatically adjusted.

[0012] Preferably, the adaptive maintenance of the damaged area of ​​the bridge determines the maintenance cycle T by dynamically adjusting maintenance parameters based on environmental temperature, humidity, and stress monitoring data, and the formula for the maintenance cycle T is:

[0013] in, This refers to the actual maintenance time. As the baseline maintenance time, For ambient temperature, Maintain a suitable ambient relative humidity; during the curing process, keep the ambient temperature between 15-30℃ and the relative humidity between 50%-70%, and spray curing agent regularly to ensure that the reinforcement layer is evenly cured.

[0014] Preferably, the modified epoxy resin sealant is composed of the following raw materials in parts by weight: 40-50 parts of bisphenol A epoxy resin, 10-15 parts of polysulfide rubber, 5-8 parts of nano silica, 8-12 parts of curing agent, and 2-3 parts of accelerator. The sealant has a tensile strength ≥30MPa and an elongation at break ≥5%.

[0015] Preferably, the primer and the topcoat are from the same system, consisting of 30-40 parts of bisphenol A epoxy resin, 5-10 parts of acetone, 6-8 parts of curing agent, and 1-2 parts of coupling agent, with an adhesion strength ≥3.5MPa.

[0016] The technical solutions provided in this application have the following advantages compared with the prior art: The overall structure provided in this application proposes a collaborative reinforcement technology that integrates precise damage location, layered gradient reinforcement, intelligent stress monitoring, and adaptive maintenance. Through damage level evaluation formulas and dynamic adjustment formulas for maintenance parameters, the reinforcement process achieves precision and intelligence. Furthermore, the use of ultrasonic-assisted bonding and prestressing tensioning technology improves the bonding density between the CFRP fabric and the base layer, avoids stress concentration, increases the structural bearing capacity by more than 30%, and extends the service life of the reinforcement layer to more than 25 years. The layered gradient reinforcement process simplifies the construction process, shortens the construction cycle by 20%, and has minimal impact on traffic. It is applicable to the reinforcement and renovation of concrete, steel, and composite structure bridges and can meet the reinforcement needs of different damage levels. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall principle structure of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Various embodiments of this application may exist in the form of a range. It should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this application. Therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in this application, it means including any referenced number (fraction or integer) within the indicated range. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this application can be purchased commercially or prepared using existing equipment.

[0022] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in this application, the terms "comprising," "including," etc., mean "including but not limited to." In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this application, "and / or" describes the relationship between related objects, indicating that three relationships may exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of a single item or a plural item. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0023] like Figure 1 As shown: This application provides a method for reinforcing a bridge, including the following steps: S1. Damage detection and localization of the channel bridge; S2. Pre-treatment of the base layer at the damaged section of the passageway bridge; S3. Layered gradient reinforcement at the damaged section of the channel bridge; S4. Intelligent stress monitoring at damaged locations on the tunnel bridge; S5. Adaptive maintenance of damaged sections of the tunnel bridge.

[0024] The damage detection and localization of the underpass bridge adopts a combination of ultrasonic tomography and fiber optic grating sensor array to conduct a comprehensive inspection of the main structure of the underpass bridge, obtain data on crack width, depth, degree of steel corrosion and concrete strength distribution, and calculate the structural damage level D to determine the key areas for reinforcement.

[0025] Specifically, the fiber optic stress sensor has a measurement range of 0-200 MPa, a measurement accuracy of ±0.5 MPa, and a data transmission rate of ≥100 Mbps.

[0026] The formula for calculating the structural damage level D is:

[0027] in: , , These are the weighting coefficients for crack width, damage depth, and steel corrosion rate, respectively. To measure the crack width, To allow for crack width, To measure the depth of damage, For structural design thickness, To measure the corrosion rate of the reinforcing steel, To allow for a certain corrosion rate, when D ≥ 0.6, the area is considered severely damaged and requires priority reinforcement.

[0028] The pretreatment of the base layer at the damaged section of the passage bridge includes surface grinding and dust removal of the reinforced area, rinsing with a high-pressure water gun and air drying. For areas with crack width > 0.2 mm, modified epoxy resin grout is injected, with the grouting pressure controlled at 0.3-0.5 MPa and the curing time ≥ 24 h.

[0029] The damaged section of the bridge is reinforced with a three-layer gradient structure. First layer: Apply primer to the base surface of the damaged area of ​​the channel bridge using an ultrasonic-assisted application process with an ultrasonic frequency of 20-30kHz and a coating thickness of 0.2-0.3mm. Curing time is 8-12 hours. Specifically, the ultrasonic-assisted coating process eliminates air bubbles between the primer and the substrate, improving adhesion density, with an air bubble content of ≤3%.

[0030] Second layer: CFRP cloth is laid on the adhesive surface, and a pre-tensioning force of 5-8MPa is applied using a pre-stressing tensioning device at a tensioning speed of 0.5mm / min. At the same time, adhesive is applied again to the CFRP cloth coating surface to ensure that the CFRP cloth is tightly bonded to the base layer. The adhesive coating thickness is 0.3-0.5mm. Based on the structural damage level, an additional layer of CFRP cloth is laid in the severely damaged area. The steps of laying the second layer of CFRP cloth and applying adhesive are repeated to form a gradient reinforcement structure of primer, double-layer CFRP cloth and topcoat. The CFRP fabric has a tensile strength ≥4000MPa, an elastic modulus ≥230GPa, a thickness of 0.15-0.2mm, and a width of 500-1000mm.

[0031] The intelligent stress monitoring of the damaged areas of the bridge includes embedding fiber optic stress sensors during the CFRP fabric laying process. The sensor spacing is 500-800mm to monitor the stress changes of the reinforcement layer in real time. The monitoring data is sent to the background system through a data transmission module. When the monitored stress value exceeds 10% of the design value, the prestressing tensioning parameters are automatically adjusted.

[0032] The adaptive maintenance of the damaged sections of the bridge is based on environmental temperature, humidity, and stress monitoring data. Maintenance parameters are dynamically adjusted to determine the maintenance cycle T, and the formula for the maintenance cycle T is:

[0033] in, This refers to the actual maintenance time. As the baseline maintenance time, For ambient temperature, Maintain a suitable ambient relative humidity; during the curing process, keep the ambient temperature between 15-30℃ and the relative humidity between 50%-70%, and spray curing agent regularly to ensure that the reinforcement layer is evenly cured.

[0034] The modified epoxy resin sealant is composed of the following raw materials in parts by weight: 40-50 parts of bisphenol A epoxy resin, 10-15 parts of polysulfide rubber, 5-8 parts of nano silica, 8-12 parts of curing agent, and 2-3 parts of accelerator. The sealant has a tensile strength ≥30MPa and an elongation at break ≥5%.

[0035] The primer and topcoat are from the same system, consisting of 30-40 parts of bisphenol A epoxy resin, 5-10 parts of acetone, 6-8 parts of curing agent, and 1-2 parts of coupling agent, with an adhesion strength ≥3.5MPa. Example

[0036] Example 1: Reinforcement Construction of Concrete Underpass Bridge Project Overview: This underpass bridge is a single-span simply supported beam bridge with a span of 10m and a deck width of 8m. It was completed in 2005. Upon inspection, multiple cracks were found in the bridge's bottom slab, with the largest crack width being 0.4mm. The steel reinforcement corrosion rate was 6.2%, and the structural damage level D = 0.4 × (0.4 / 0.3) + 0.35 × (0.1 / 0.5) + 0.25 × (6.2 / 5) = 0.65, classifying it as a severely damaged area. Therefore, reinforcement using the method of this invention is required. Damage detection and location of the underpass bridge: Using ultrasonic tomography and fiber optic grating sensor array, a crack depth of 0.1m and a steel reinforcement corrosion rate of 6.2% were detected, and the 3m×8m area in the middle of the bottom slab was identified as the key reinforcement area; Pre-treatment of the base layer at the damaged section of the underpass: The surface of the key reinforcement area is ground to remove laitance and loose concrete. After rinsing with a high-pressure water gun, it is allowed to air dry naturally. For areas with crack width > 0.2mm, modified epoxy resin grout is injected at a grouting pressure of 0.4MPa and cured for 24 hours. Layered gradient reinforcement at the damaged section of the bridge: First layer: Apply primer, ultrasonic frequency 25kHz, coating thickness 0.25mm, cure for 10 hours; Second layer: Lay CFRP cloth (tensile strength 4200MPa, elastic modulus 235GPa), apply a pre-tension of 6MPa, tension speed 0.5mm / min, and apply adhesive to the coated surface with a thickness of 0.4mm; Third layer: Lay an additional layer of CFRP cloth in the key reinforcement areas, and repeat the prestressing tensioning and surface adhesive application steps; Intelligent stress monitoring at the damaged section of the bridge: Embedded fiber optic stress sensors with a spacing of 600mm monitor stress changes in real time. When the monitored stress value reaches 105% of the design value, the preload is automatically adjusted to 5.5MPa. Adaptive maintenance of damaged sections of the bridge: During construction, the ambient temperature is 20℃ and the relative humidity is 65%. According to formula (2), the actual maintenance time is calculated as T = 7 × (1 + 0.02 × (25-20) - 0.01 × (65-60)) = 7.35 days. Take 8 days. During the maintenance process, maintain the ambient temperature at 18-28℃ and the relative humidity at 55%-65%, and spray the maintenance agent regularly.

[0037] After the reinforcement was completed, a load test was conducted on the bridge. The results showed that the structural bearing capacity was increased by 35%, the bond strength between the reinforcement layer and the base layer reached 4.2 MPa, and no air bubbles were generated. After 12 months of use and monitoring, no new cracks or detachment of the reinforcement layer were observed, and the reinforcement effect was significant.

[0038] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for reinforcing a bridge, characterized in that, Includes the following steps: S1. Damage detection and localization of the channel bridge; S2. Pre-treatment of the base layer at the damaged area of ​​the passage bridge; S3. Layered gradient reinforcement at the damaged section of the channel bridge; S4. Intelligent stress monitoring at damaged locations on the tunnel bridge; S5. Adaptive maintenance of damaged sections of the tunnel bridge.

2. The method for reinforcing a bridge according to claim 1, characterized in that: The damage detection and localization of the underpass bridge adopts a combination of ultrasonic tomography and fiber optic grating sensor array to conduct a comprehensive inspection of the main structure of the underpass bridge, obtain data on crack width, depth, degree of steel corrosion and concrete strength distribution, and calculate the structural damage level D to determine the key areas for reinforcement.

3. The method for reinforcing a bridge according to claim 2, characterized in that: The formula for calculating the structural damage level D is: in: , , These are the weighting coefficients for crack width, damage depth, and steel corrosion rate, respectively. To measure the crack width, To allow for crack width, To measure the depth of damage, For structural design thickness, To measure the corrosion rate of the reinforcing steel, To allow for a certain corrosion rate, when D ≥ 0.6, the area is considered severely damaged and requires priority reinforcement.

4. The method for reinforcing a bridge according to claim 1, characterized in that: The pretreatment of the base layer at the damaged section of the passage bridge includes surface grinding and dust removal of the reinforced area, rinsing with a high-pressure water gun and air drying. For areas with crack width > 0.2 mm, modified epoxy resin grout is injected, with the grouting pressure controlled at 0.3-0.5 MPa and the curing time ≥ 24 h.

5. The method for reinforcing a bridge according to claim 1, characterized in that: The damaged section of the bridge is reinforced with a three-layer gradient structure. First layer: Apply primer to the base surface of the damaged area of ​​the channel bridge using an ultrasonic-assisted application process with an ultrasonic frequency of 20-30kHz and a coating thickness of 0.2-0.3mm. Curing time is 8-12 hours. Second layer: CFRP cloth is laid on the adhesive surface, and a pre-tensioning force of 5-8MPa is applied using a pre-stressing tensioning device at a tensioning speed of 0.5mm / min. At the same time, adhesive is applied again to the CFRP cloth coating surface to ensure that the CFRP cloth is tightly bonded to the base layer. The adhesive coating thickness is 0.3-0.5mm. Third layer: Based on the structural damage level, lay an additional layer of CFRP cloth in the severely damaged area, and repeat the steps of laying the second layer of CFRP cloth and applying adhesive to form a gradient reinforcement structure of primer, double layer of CFRP cloth and topcoat. The CFRP fabric has a tensile strength ≥4000MPa, an elastic modulus ≥230GPa, a thickness of 0.15-0.2mm, and a width of 500-1000mm.

6. The method for reinforcing a bridge according to claim 1, characterized in that: The intelligent stress monitoring of the damaged areas of the bridge includes embedding fiber optic stress sensors during the CFRP fabric laying process. The sensor spacing is 500-800mm to monitor the stress changes of the reinforcement layer in real time. The monitoring data is sent to the background system through a data transmission module. When the monitored stress value exceeds 10% of the design value, the prestressing tensioning parameters are automatically adjusted.

7. The method for reinforcing a bridge according to claim 1, characterized in that: The adaptive maintenance of the damaged sections of the bridge is based on environmental temperature, humidity, and stress monitoring data. Maintenance parameters are dynamically adjusted to determine the maintenance cycle T, and the formula for the maintenance cycle T is: in, This refers to the actual maintenance time. As the baseline maintenance time, For ambient temperature, Maintain a suitable ambient relative humidity; during the curing process, keep the ambient temperature between 15-30℃ and the relative humidity between 50%-70%, and spray curing agent regularly to ensure that the reinforcement layer is evenly cured.

8. The method for reinforcing a bridge according to claim 4, characterized in that: The modified epoxy resin sealant is composed of the following raw materials in parts by weight: 40-50 parts of bisphenol A epoxy resin, 10-15 parts of polysulfide rubber, 5-8 parts of nano silica, 8-12 parts of curing agent, and 2-3 parts of accelerator. The sealant has a tensile strength ≥30MPa and an elongation at break ≥5%.

9. The method for reinforcing a bridge according to claim 1, characterized in that: The primer and topcoat are from the same system, consisting of 30-40 parts of bisphenol A epoxy resin, 5-10 parts of acetone, 6-8 parts of curing agent, and 1-2 parts of coupling agent, with an adhesion strength ≥3.5MPa.

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