CARBON FIBER REINFORCED POLYMER (CFRP) STRENGTHENING SYSTEM WITH REINFORCEMENT AND CATHODIC PROTECTION FUNCTIONS FOR STEEL BRIDGE

Abstract

Provided is a carbon fiber reinforced polymer (CFRP) strengthening system with reinforcement and cathodic protection functions for a steel bridge. The CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge includes a steel beam component, a CFRP plate, clamping plate assemblies, water swellable cotton, insulating friction plates, a current stabilized power source, and a connecting lead, where the CFRP plate is provided below a lower surface of the steel beam component; clamping plate assemblies are respectively detachably connected to two ends of the steel beam component; the insulating friction plate is provided between the clamping plate assembly and a clamping contact surface of the CFRP plate; the water swellable cotton is provided between the CFRP plate and the lower surface of the steel beam component; and the current stabilized power source is provided beneath the steel beam component.

Claims

1. A carbon fiber reinforced polymer (CFRP) strengthening system with reinforcement and cathodic protection functions for a steel bridge, comprising a steel beam component, a CFRP plate, clamping plate assemblies, water swellable cotton, insulating friction plates, a current stabilized power source, and a connecting lead, wherein the CFRP plate is provided below a lower surface of the steel beam component; clamping plate assemblies are respectively detachably connected to two ends of the steel beam component; two ends of the CFRP plate are respectively located in the clamping plate assemblies at the two ends of the steel beam component; the insulating friction plate is provided between the clamping plate assembly and a clamping contact surface of the CFRP plate; the water swellable cotton is provided between the CFRP plate and the lower surface of the steel beam component; the water swellable cotton comes in contact with the CFRP plate and the lower surface of the steel beam component; the current stabilized power source is provided beneath the steel beam component; and the current stabilized power source comprises a positive electrode connected to one end of the CFRP plate through the lead, and a negative electrode connected through the lead to an end of the steel beam component away from the one end of the CFRP plate connected to the lead.

2. The CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge according to claim 1, wherein the clamping plate assembly comprises a U-shaped lower clamping plate; rectangular upper clamping plates are respectively provided at two ends of the U-shaped lower clamping plate; the rectangular upper clamping plate comprises one end overlapping on the end of the U-shaped lower clamping plate, and the other end acting on the steel beam component; a portion of the rectangular upper clamping plate close to the end of the U-shaped lower clamping plate is provided with at least one bolt; the bolt penetrates through the rectangular upper clamping plate and the U-shaped lower clamping plate; and a threaded end of the bolt is provided with a nut in threaded connection with the bolt.

3. The CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge according to claim 1, wherein the current stabilized power source comprises at least one storage battery; a plurality of solar panels are provided on the steel beam component; and the solar panels are electrically connected to the storage battery.

4. The CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge according to claim 3, wherein the current stabilized power source is provided beneath the steel beam component; and a waterproof assembly is provided on an outer surface of the current stabilized power source.

5. The CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge according to claim 1, wherein at least one end of the CFRP plate is provided with a tensioning device; a surface of the tensioning device is detachably connected to the steel beam component; and an output end of the tensioning device is detachably connected to one end of the CFRP plate.

6. The CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge according to claim 1, wherein a portion of the end of the CFRP plate close to the clamping plate assembly is provided with a prestress compensation assembly; the prestress compensation assembly comprises a U-shaped mounting frame; two ends of the U-shaped mounting frame are fixedly connected to an edge of the lower surface of the steel beam component in a width direction; a U-shaped connecting frame is provided in the U-shaped mounting frame; a pulling rod is provided in the U-shaped connecting frame; two ends of the pulling rod are respectively fixed at two sides of the U-shaped connecting frame; the pulling rod comes in contact with an upper surface of the CFRP plate; a plurality of uniformly distributed linear motors are provided at an outer side of a closed end of the U-shaped mounting frame; a housing of each of the linear motors is fixed on the U-shaped mounting frame; an output end of the linear motor is fixed on the U-shaped connecting frame; a force sensor is provided on the CFRP plate; both the force sensor and the linear motor are electrically connected to the current stabilized power source; and the force sensor is configured to control working time and a working state of the linear motor.

7. The CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge according to claim 6, wherein limiting rods are further symmetrically provided in the U-shaped mounting frame; the limiting rods are respectively fixed at two sides of the U-shaped mounting frame; and the limiting rods are provided along a length direction of the U-shaped mounting frame, and come in contact with a lower surface of the CFRP plate.

8. The CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge according to claim 6, wherein chutes are respectively formed in middles of two sides of the U-shaped mounting frame; and the two ends of the U-shaped connecting frame are respectively located in the chutes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the objectives, technical solutions and beneficial effects of the present disclosure clearer, the present disclosure provides the following drawings:

[0020] FIG. 1 is a schematic plan view of a CFRP strengthening system according to the present disclosure;

[0021] FIG. 2 is a schematic side sectional view of a CFRP strengthening system according to the present disclosure;

[0022] FIG. 3 is a schematic stereoscopic view of a CFRP strengthening system according to the present disclosure;

[0023] FIG. 4 is a schematic stereoscopic view of a CFRP strengthening system after a steel beam component is removed according to the present disclosure;

[0024] FIG. 5 is a schematic stereoscopic view of an upper clamping plate, a lower clamping plate and an insulating friction plate in a CFRP strengthening system according to the present disclosure;

[0025] FIG. 6 is a schematic stereoscopic view of a tensioning mechanism in a CFRP strengthening system according to the present disclosure; and

[0026] FIG. 7 is a schematic view illustrating that a tensioning mechanism acts on a CFRP plate in a CFRP strengthening system according to the present disclosure.

REFERENCE NUMERALS

[0027] 1steel beam component, 2CFRP plate, 3insulating friction plate, 4U-shaped lower clamping plate, 5rectangular upper clamping plate, 6water swellable cotton, 7current stabilized power source, 8lead, 9bolt, 10nut, 11U-shaped mounting frame, 12chute, 13limiting rod, 14pulling rod, 15U-shaped connecting frame, and 16linear motor.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] As shown in FIGS. 1-7, the present disclosure provides a CFRP strengthening system with reinforcement and cathodic protection functions for a steel bridge, including a steel beam component 1. Each steel beam component 1 varies in shape. In a specific implementation, the steel beam component 1 is an I-shaped steel beam component 1. The specific strengthening system includes a CFRP plate 2, clamping plate assemblies, water swellable cotton 6, insulating friction plates 3, a current stabilized power source 7, and a connecting lead 8. The CFRP plate 2 is provided below a lower surface of the steel beam component 1. The lower surface of the steel beam component 1 is described as follows: With the bridge as an example, the lower surface of the steel beam component 1 refers to a side away from the bridge. The clamping plate assemblies are respectively detachably connected to two ends of the steel beam component 1. The clamping plate assemblies may change depending on the shape of the steel beam component, and are mainly configured to clamp two ends of the CFRP plate 2, which is not repeated herein. Specifically, the two ends of the CFRP plate 2 are respectively located in the clamping plate assemblies at the two ends of the steel beam component 1. The insulating friction plate 3 is provided between the clamping plate assembly and a clamping contact surface of the CFRP plate 2, and configured to isolate an electrical conductivity of the CFRP plate 2 and an electrical conductivity of the clamping plate assembly, and reinforce a clamping effect. Meanwhile, the water swellable cotton 6 may be made of sodium polyacrylate (SAP), which is a commonly used super absorbent polymer, and can absorb water up to hundreds to thousands of times its weight. The water swellable cotton 6 is provided between the CFRP plate 2 and the lower surface of the steel beam component 1. The water swellable cotton 6 comes in contact with the CFRP plate 2 and the lower surface of the steel beam component 1. The current stabilized power source 7 is provided beneath the steel beam component 1. The current stabilized power source 7 includes a positive electrode connected to one end of the CFRP plate 2 through the lead 8, and a negative electrode connected through the lead 8 to an end of the steel beam component 1 away from the one end of the CFRP plate 2 connected to the lead 8.

[0029] Specifically, the working principle of the above technical solution is as follows:

[0030] When the steel beam is exposed to corrosive environmental factors such as rainwater or water vapor, the water swellable cotton 6 on the CFRP plate 2 absorbs accumulated water on the steel beam component through a capillary action. The accumulated water serves as a conductive medium, connecting the positive electrode of the current stabilized power source 7, the CFRP plate 2, the negative electrode of the current stabilized power source 7, and the steel beam component together to form a conductive path. The current stabilized power source 7 offers a stable current intensity, such that a cathodic electric field is established for a metal surface, and the metal surface is in an electronic-receiving state, thereby suppressing oxidation reaction that corrodes the steel beam component. Due to large areas of the CFRP plate 2 and the water swellable cotton 6, a current can be uniformly distributed on a surface of the steel beam component to yield a desirable protection effect. By connecting the positive electrode and the negative electrode of the power source to the two ends of the steel beam component, the current can be distributed along the whole steel beam component to yield a desirable corrosion protection effect. In response to a dry weather, moisture in the water swellable cotton 6 is vaporized, such that a current path is open, and the steel beam component is not protected. This can reduce power consumption, and inhibit continuous anodic oxidation of the CFRP plate 2, extending a service life of a CFRP anode.

[0031] Meanwhile, it is further to be noted that since the clamping plate assembly for the CFRP plate 2 is also made of steel materials, the insulating friction plate 3 is provided between the clamping plate assembly and the CFRP plate 2 to inhibit the current from forming a loop through clamping plates, as shown in FIG. 2. In addition to electrical insulation, the insulating friction plate 3 can enhance friction on the prestressed CFRP plate 2, reducing a loss of prestress after tensioning.

[0032] In the above technical solution, specific mounting steps on the steel beam component 1 are as follows:

[0033] Firstly, the CFRP plate 2 is tensioned to a specified prestress level, with a mid-span position bonded with the water swellable cotton 6, and a position close to a beam bottom separated by the insulating friction plate 3. Secondly, the insulating friction plate 3 is attached to a corresponding position of a lower portion of the CFRP plate 2, and fastened with a U-shaped lower clamping plate 4, a rectangular upper clamping plate 5, a bolt 9, and a nut 10. Thirdly, a tensioning device is removed, and an excess CFRP at two sides of the clamping plate assembly is cut. Fourthly, the positive electrode of the current stabilized power source 7 is connected to one end of the CFRP plate 2 through the lead 8, and the negative electrode of the current stabilized power source 7 is connected to an upper portion of the other end of the steel beam component. Fifthly, the current stabilized power source 7 is powered on, and adjusted to a specified protective current. The current can be adjusted according to the prior art, which is not repeated herein.

[0034] In an implementable manner, the clamping plate assembly includes a U-shaped lower clamping plate 4. Rectangular upper clamping plates 5 are respectively provided at two ends of the U-shaped lower clamping plate 4. The rectangular upper clamping plate 5 includes one end overlapping with the end of the U-shaped lower clamping plate 4, and the other end acting on the steel beam component 1. A portion of the rectangular upper clamping plate 5 close to the end of the U-shaped lower clamping plate 4 is provided with at least one bolt 9. The bolt 9 penetrates through the rectangular upper clamping plate 5 and the U-shaped lower clamping plate 4. A threaded end of the bolt 9 is provided with a nut 10 in threaded connection with the bolt 9.

[0035] The clamping plate assembly is structured simply and mounted conveniently. Meanwhile, the clamping plate assembly is connected to the steel beam component through the bolt 9. The clamping plate assembly connected to the steel beam component together is also viewed as a cathode, namely inhibited from corrosion in harsh environments. This correspondingly solves problems of anchorage force reduction, relaxation in prestressing and the like caused by rust of the steel clamping plate assembly. Moreover, this unbonded anchoring system inhibits the interface problem of the conventional bonded method, and provides more reliable mechanical anchorage, thereby reinforcing the long-term stability and reliability of the strengthening.

[0036] In an implementable manner, the current stabilized power source 7 includes at least one storage battery. A plurality of solar panels are provided on the steel beam component 1. The solar panels are electrically connected to the storage battery. Since the current stabilized power source 7 includes the storage battery, the solar panels and the like, solar energy charged to the storage battery can be converted into electric energy for use during rainy weather conditions. This saves the electric energy, and can be available for bridges in some remote regions where grid connection is impractical.

[0037] In an implementable manner, the current stabilized power source 7 is provided beneath the steel beam component 1. A waterproof assembly is provided on an outer surface of the current stabilized power source 7. At least one end of the CFRP plate 2 is provided with the tensioning device. A surface of the tensioning device is detachably connected to the steel beam component 1. An output end of the tensioning device is detachably connected to one end of the CFRP plate 2. The specific structure of the tensioning device is the prior art, and is not repeated herein. For example, the hydraulic tensioning device can be configured to tension the CFRP plate 2 to form a prestress.

[0038] In an implementable manner, the CFRP plate 2 experiences relaxation in prestressing after used for a long time. That is, the CFRP plate 2 has a relaxation phenomenon. Hence, a portion of the end of the CFRP plate 2 close to the clamping plate assembly is provided with a prestress compensation assembly. The prestress compensation assembly includes a U-shaped mounting frame 11. Two ends of the U-shaped mounting frame 11 are fixedly connected to an edge of the lower surface of the steel beam component 1 in a width direction. A U-shaped connecting frame 15 is provided in the U-shaped mounting frame 11. A pulling rod 14 is provided in the U-shaped connecting frame 15. Two ends of the pulling rod 14 are respectively fixed at two sides of the U-shaped connecting frame 15. The pulling rod 14 comes in contact with an upper surface of the CFRP plate 2. A plurality of uniformly distributed linear motors 16 are provided at an outer side of a closed end of the U-shaped mounting frame 11. A housing of each of the linear motors 16 is fixed on the U-shaped mounting frame 11. An output end of the linear motor 16 is fixed on the U-shaped connecting frame 15. A force sensor is provided on the CFRP plate 2. The force sensor may be a tension sensor, since it is specially designed to measure a tensional force or tensile force, and generally configured to measure the tensional force of a wire, a rope or a steel wire. Meanwhile, the force sensor may further be a strain gauge for measurement. Both the force sensor and the linear motor 16 are electrically connected to the current stabilized power source 7. The force sensor is configured to send a signal to a control board according to a measured stress change, thereby controlling working time and a working state of the linear motor 16 through the control board (such as an industrial control board). The control board is the prior art, and can be realized by programmable logic controller (PLC) programming, which is not repeated herein.

[0039] The prestress compensation assembly has the following working principle: When detecting that the prestress on the CFRP plate 2 changes, with a variation reaching a preset range, the force sensor sends the signal to the control board, such that the control board drives the linear motor 16 to retract. By this time, under an action of the pulling rod 14, the retracted linear motor 16 drives the CFRP plate 2 to bend and move down for tensioning, thereby compensating and reinforcing the prestress to improve the strengthening effect.

[0040] In an implementable manner, limiting rods 13 are further symmetrically provided in the U-shaped mounting frame 11. The limiting rods 13 are respectively fixed at two sides of the U-shaped mounting frame 11. The limiting rods 13 are provided along a length direction of the U-shaped mounting frame 11, and come in contact with a lower surface of the CFRP plate 2. With the limiting rod 13, a bending and downward-moving region of the CFRP plate 2 outside the limiting rod 13 can be limited. That is, only the CFRP plate 2 between two limiting rods 13 can move down and bend. In tensioning of prestress compensation, the CFRP plate 2 outside the limiting rod 13 does not move down, without changing a height and a distance with the water swellable cotton 6. This can ensure that the water swellable cotton 6 can come in contact with the CFRP plate 2 all the time after absorbing the water, improving the electrical conductivity and corrosion resistance.

[0041] In an implementable manner, chutes 12 are respectively formed in middles of two sides of the U-shaped mounting frame 11. Two ends of the U-shaped connecting frame 15 are respectively located in the chutes 12. With the chutes 12, the two ends of the U-shaped connecting frame 15 can be laterally limited, ensuring tensioning of the linear motor 16. When the CFRP plate 2 moves down and bends, a transferred lateral moment acts on a sidewall of the chute 12, rather than the output end of the linear motor 16. This inhibits the output end of the linear motor 16 from suffering the lateral moment, ensuring the working environment and working effect of the linear motor 16.

[0042] Finally, it should be noted that the above preferred embodiments are merely intended to illustrate rather than limit the technical solutions of the present disclosure. Although the present disclosure has been described in detail through the above preferred embodiments, those skilled in the art should appreciate that various changes may be made to the present disclosure in the form and detail without departing from the scope defined by the claims of the present disclosure.