A prestressed reinforcement device and reinforcement method for bridges without anchorages

Abstract

The present invention discloses a bridge prestressed reinforcement device without anchorages and a reinforcement method. The bridge prestressed reinforcement device without anchorages includes: a plurality of prestressed members, and the plurality of prestressed members are fixedly spaced apart on the bottom surface of the beam body through an adhesive layer; a stress dispersion layer, which is fixedly covered at both ends of the bottom surface of the beam body, and the stress dispersion layer is arranged between the bottom surface of the beam body and the ends of the prestressed members; a heating device, which is used to heat each of the prestressed members. The present invention effectively improves the construction efficiency of bridge prestressed reinforcement, reduces the construction difficulty, and avoids the problems of stress concentration and unstable reinforcement effect existing in other external prestresses.

Description

Technical Field

[0001] The present invention relates to the technical field of beam reinforcement, and more specifically, to a bridge anchorless prestressed reinforcement device and reinforcement method. Background Art

[0002] Traditional prestressed reinforcement methods often include prestressed materials, steering blocks, anchor blocks, anchor pads, clamps and clips. During the construction process, it is necessary to drill holes in the bottom of the concrete to plant reinforcement, then weave steel cages, lay prestressed pipes and anchor devices, and then set up formwork supports; in order to achieve concrete pouring, it is often necessary to drill holes in the bridge deck for pouring, which not only destroys the original bridge structure, but also affects the reinforcement effect due to the loose concrete pouring; at the same time, the prestressing tensioning work needs to wait for 28 days after the concrete pouring. This traditional method has the disadvantages of uncontrollable quality, long construction period, cumbersome process, high cost, and stress concentration in the anchor block. A new technology is used to solve the above problems. The Chinese invention patent application with publication number CN 116815656A discloses a curved bonded prestressed carbon fiber cable reinforcement device and its construction process, including a carbon fiber cable, a fixed-end anchor assembly, a tensioning-end anchor assembly, a tensioning tool, a plurality of steering restraints and a jack for cable tensioning. Anchors are fixed at both ends of the carbon fiber cable. The fixed-end anchor assembly is used to consolidate with the component to facilitate mechanical conversion and realize automatic centering and leveling during the tensioning process. The tensioning-end anchor assembly is consolidated with the component and is used to install the tensioning tool to realize the application of prestress. The tensioning tool is used to realize reverse tensioning of the carbon fiber cable to apply prestress. The carbon fiber cable passes through a plurality of steering restraints. The steering restraint is used to adaptively adjust the angle of the carbon fiber cable within a specified range so that the angle transition of the carbon fiber cable is smooth and tightly fits and bonds to the surface of the component to be reinforced. The Chinese invention patent application with publication number CN113027165A discloses a lightweight external prestressed reinforcement system including two anchor units, at least one steel strand and a number of vibration-damping cable clamps. The two anchor units are respectively arranged at the two ends of the bottom surface of the bridge, and the vibration-damping cable clamps are evenly arranged on the bottom surface of the bridge between the anchor units, and the steel strand passes through the vibration-damping cable clamps. The processes used in the above two schemes are cumbersome, and still require anchors, clamps, tensioning devices and processes, resulting in problems such as difficulty in reinforcement construction. Therefore, there is an urgent need for a prestressed reinforcement device without anchors, clamps, and tensioning processes, which can meet the reinforcement requirements while achieving the requirements of short construction period, good quality, simple process, low carbon and environmental protection. Summary of the invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0004] In order to achieve these purposes and other advantages according to the present invention, a bridge anchorless prestressed reinforcement device is provided, comprising:

[0005] Multiple prestressed members, and a plurality of the prestressed members are fixedly spaced apart on the bottom surface of the beam body through an adhesive layer;

[0006] A stress dispersion layer, which is fixedly covered at both ends of the bottom surface of the beam body, and the stress dispersion layer is arranged between the bottom surface of the beam body and the ends of the prestressed members;

[0007] A heating device for heating each of the prestressed members.

[0008] Preferably, the stress dispersion layer is a carbon fiber cloth, a carbon fiber board or an FRP sheet.

[0009] Preferably, the adhesive layer is a heat-insulating glue, and the heat-conducting coefficient of the heat-insulating glue is less than 0.19 w / (m•K), the tensile strength is not less than 5 Mpa, and the compressive strength is not less than 30 Mpa.

[0010] Preferably, the prestressed member is made of steel or fiber composite material.

[0011] Another object of the present invention is to provide a method for prestress reinforcement of a bridge without anchor fittings, comprising the following steps:

[0012] S1. Paste a stress dispersion layer at both ends of the bottom surface of the beam body;

[0013] S2. Perform surface treatment on the parts of the bottom surface of the beam body where prestressed members need to be arranged;

[0014] S3. Coat heat-insulating glue on the parts after surface treatment;

[0015] S4. Install each prestressed member and press it tightly with a temporary fixing device;

[0016] S5. Simultaneously heat each prestressed member by using a heating device and keep it warm until the heat-insulating glue is cured.

[0017] Preferably, in step S1, the length of the stress dispersion layer is the same as the width of the bottom surface of the beam body.

[0018] Preferably, in step S2, the surface treatment method is grinding or chiseling, and the surface treatment depth is not less than 5 mm.

[0019] Preferably, in step S5, the heating temperature is 50 - 500 °C.

[0020] Preferably, in step S5, the heating temperature is 80 - 150 °C.

[0021] The present invention has at least the following beneficial effects:

[0022] 1. The prestress reinforcement device and method for bridges without anchorages provided by the present invention heat each prestressed component through a heating device, and utilize the deformation elongation and shrinkage after cooling of the prestressed components to generate high-strength tensile forces as prestress to resist the bending moment and tensile stress of the beam body, thereby realizing the reinforcement of the beam body. During the reinforcement process, there is no need to wait for the concrete age, and there are no complicated processes such as tensioning and anchoring, which greatly simplifies the processes, equipment, and materials of prestress construction, effectively improves the construction efficiency, and reduces the construction difficulty.

[0023] 2. The prestress reinforcement device and method for bridges without anchorages provided by the present invention realize the full bonding of prestress on the beam body to be reinforced, avoiding the problems of stress concentration existing in other external prestresses, large forces on the anchorage blocks or deviator blocks that are prone to damage, and significant influence of the reinforcement effect on construction.

[0024] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a top view of the prestress reinforcement device for bridges without anchorages of the present invention at the bottom surface of the beam body;

[0026] Figure 2 It is a side structure schematic diagram of the prestress reinforcement device for bridges without anchorages of the present invention;

[0027] Figure 3 It is a structure schematic diagram of the fixing device of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following further detailed description of the present invention is provided in conjunction with the accompanying drawings, so that those skilled in the art can implement it with reference to the text of the specification.

[0029] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present invention, the orientation or positional relationships indicated by the terms "horizontal", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0030] As Figure 1 and Figure 2 shown, the present invention provides a prestress reinforcement device for bridges without anchorages, including:

[0031] Multiple prestressed members 3, and multiple said prestressed members 3 are fixedly spaced apart on the bottom surface 2 of the beam body through an adhesive layer 4;

[0032] A stress dispersion layer 1, which is fixedly covered at both ends of the bottom surface 2 of the beam body, and the stress dispersion layer 1 is arranged between the bottom surface 2 of the beam body and the ends of the prestressed members 3;

[0033] A heating device for heating each of the prestressed members 3.

[0034] In this technical solution, each of the prestressed members 3 is heated by the heating device. After heating, the prestressed members 3 will deform and elongate, and then are fixed on the bottom surface 2 of the beam body by the adhesive layer 4. After the heating is stopped, the prestressed members 3 gradually cool and contract, thereby generating a high-strength tensile force as prestress to resist the bending moment and tensile stress of the beam body, realizing the reinforcement of the beam body. The prestressed members 3 are prestressed and fully adhered to the beam body to be reinforced through the adhesive layer 4. The prestress at both ends of the prestressed members 3 is further dispersed through the stress dispersion layer 1, effectively avoiding the stress concentration problem existing in other external prestresses. In the above reinforcement process, there is no need to wait for the age of the concrete, and there are no complicated tensioning, anchoring and other processes, greatly simplifying the processes, equipment and materials of prestress tensioning, saving the construction period and cost.

[0035] In another technical solution, the stress dispersion layer 1 is a carbon fiber cloth, a carbon fiber plate or an FRP sheet. Through their high elastic modulus, high strength and other characteristics, carbon fiber materials and FRP sheets can efficiently transfer and disperse local concentrated stress to a larger area.

[0036] In another technical solution, the adhesive layer 4 is a heat-insulating adhesive, and the heat conductivity coefficient of the heat-insulating adhesive is less than 0.19 w / (m•K), the tensile strength is not less than 5 Mpa, and the compressive strength is not less than 30 Mpa. Preferably, the heat-insulating adhesive can be a high-strength heat-insulating adhesive, such as polyurethane adhesive, epoxy resin adhesive, ceramic adhesive, silicone adhesive, inorganic high-temperature adhesive, etc.

[0037] In another technical solution, the prestressed member 3 is made of steel or fiber composite material. By using the high tensile strength, high elastic modulus and thermal expansion and contraction characteristics of steel or fiber composite material, prestress is generated during the heating and cooling processes to realize the reinforcement of the beam body. The prestressed member 3 can be sheet-shaped or column-shaped.

[0038] The present invention also provides a method for prestress reinforcement of a bridge without an anchor, using the prestress reinforcement device for a bridge without an anchor, including the following steps:

[0039] S1. Paste the stress dispersion layer 1 at both ends of the bottom surface 2 of the beam body;

[0040] S2. Perform surface treatment on the part of the bottom surface 2 of the beam body where the prestressed member 3 needs to be provided.

[0041] S3. Coat heat-insulating glue on the surface-treated part.

[0042] S4. Install each prestressed member 3 and press it tightly with a temporary fixing device.

[0043] S5. Use a heating device to heat each prestressed member 3 simultaneously and keep it warm until the heat-insulating glue cures.

[0044] In step S1, the length of the stress dispersion layer 1 is the same as the width of the bottom surface 2 of the beam body. As Figure 1 shown, the stress dispersion layer 1 should completely cover the end of the bottom surface 2 of the beam body and satisfy that the end of the prestressed member 3 overlaps on it to ensure the stress dispersion effect.

[0045] In step S2, the surface treatment method is grinding or chiseling, and the surface treatment depth is not less than 5 mm. The bonding firmness of the bonding layer 4 is increased through surface treatment.

[0046] In step S3, the heat-insulating glue should completely cover the part where the prestressed member 3 contacts the bottom surface 2 of the beam body to achieve full bonding of the prestress to the beam body to be strengthened.

[0047] In step S4, install the prestressed member 3 cut according to the beam body size at the position coated with the heat-insulating glue and press it tightly with the temporary fixing device to prevent the prestressed member 3 from separating from the glue. The temporary fixing device can adopt a fixing device that is easy to disassemble and commonly used in engineering, such as tape, and paste and fix the prestressed member 3 to the beam body through the tape; it can also be used as Figure 3Fix with the fixed device shown. The fixed device includes: a support plate 51, with telescopic legs 55 provided at both ends respectively. A vacuum suction cup 54 is provided at the bottom of the leg 55. The vacuum suction cup 54 is connected to a vacuum pumping device through a pipeline; the support plate 51 spans across each of the prestressed members 3, and a pressing plate 53 is provided corresponding to each of the prestressed members 3. An elastic member 53 is provided between the pressing plate 53 and the support plate 51. First, set the length of the leg 55 to match the thickness of the prestressed member 3. After aligning each of the pressing plates 53 with each of the prestressed members 3, turn on the vacuum pumping device to make each suction cup adsorb on the beam body. During this process, each elastic member 52 is compressed, and then each of the prestressed members 3 is fixed through each of the pressing plates 53. In actual use, an industrial suction cup and a vacuum system that meet the adsorption of the concrete structure can be selected. And multiple groups of the fixed devices are set according to the length of the prestressed member. After the heat-insulating glue is fixed, first adjust the lengths of the legs on both sides of the support plate to slowly release the rebound force of each elastic member, and then release the adsorption of the suction cup.

[0048] In step S5, the heating temperature is 50 - 500 °C. Further, the heating temperature is 80 - 150 °C. The heating device only needs to satisfy that the prestressed member 3 deforms and elongates due to heat. The specific heating method can be selected from the commonly used methods in engineering construction, such as arc heating, resistance heating, high-frequency induction heating, electric heating, furnace heating, laser heating, etc., which are not limited here. When using the electric heating method, the prestressed member 3 should be insulated, such as coating with insulating glue, wrapping with insulating materials, etc. During the heating process, before the heat-insulating glue cures, the vertical displacement of the prestressed member 3 is restricted by the temporary fixing device, but its deformation and elongation after heating are not restricted. After the heat-insulating glue cures, the prestressed member 3 after deformation and elongation is fixed, so that the cooled prestressed member 3 provides tensile force to the beam body to be strengthened.

[0049] In a certain bridge strengthening project, a Q460 steel plate with a cross-section of 5 mm * 100 mm is used as the prestressed member. A heating device is used to heat the prestressed member. After heating to 120 °C, it is kept warm until the heat-insulating glue cures. The comparison of the strengthening implementation effects with the conventional prestressed tendon tensioning strengthening method is shown in Table 1 below.

[0050] Table 1 Comparison of Strengthening Implementation Effects

[0051]

[0052] As can be seen from Table 1, with the strengthening method of the present invention, the tensile force provided by two Q460 steel plates of 5mm * 100mm is equivalent to that provided by a 1860 high-strength prestressed tendon of φ14mm in the conventional prestressed tendon tensioning strengthening method. Moreover, compared with the conventional prestressed tendon strengthening, the strengthening method provided by the present invention does not require a huge anchoring device, avoiding the cumbersome on-site construction such as drilling holes, implanting steel bars, formwork support, installation of prestressed tendons and prestress tensioning, and concrete pouring, greatly improving the construction efficiency and reducing the construction difficulty.

[0053] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated examples here.

Claims

1. A prestressed reinforcement device for bridges without anchorages, characterized in that, Including: A plurality of prestressed members, and the plurality of prestressed members are fixedly spaced apart on the bottom surface of the beam body through an adhesive layer; The prestressed member is made of steel or fiber composite material; the adhesive layer is a heat-insulating glue; A stress dispersion layer, which is fixedly covered at both ends of the bottom surface of the beam body, and the stress dispersion layer is arranged between the bottom surface of the beam body and the end of the prestressed member; the stress dispersion layer is a carbon fiber cloth, a carbon fiber plate or an FRP sheet; A heating device for heating each of the prestressed members; After the heat-insulating glue is cured, the deformed and elongated prestressed member is fixed, so that the cooled prestressed member provides a tensile force to the beam body to be strengthened.

2. The prestressed reinforcement device for bridges without anchorages according to claim 1, wherein The heat-insulating glue has a thermal conductivity less than 0.19 w / (m•K), a tensile strength not less than 5 Mpa, and a compressive strength not less than 30 Mpa.

3. A method for prestress reinforcement of a bridge without anchorages, using the bridge prestress reinforcement device without anchorages as described in claim 1, characterized in that, Including the following steps: S1. Paste a stress dispersion layer at both ends of the bottom surface of the beam body; S2. Perform surface treatment on the part of the bottom surface of the beam body where the prestressed member needs to be arranged; S3. Coat the heat-insulating glue on the surface-treated part; S4. Install each prestressed member and press it with a temporary fixing device; S5. Simultaneously heat each prestressed member with a heating device and keep it warm until the heat-insulating glue is cured; during the heating process, before the heat-insulating glue is cured, the vertical displacement of the prestressed member is restricted by the temporary fixing device, but its deformation elongation after being heated is not restricted.

4. The method for prestress reinforcement of a bridge without anchor as claimed in claim 3, characterized in that In step S1, the length of the stress dispersion layer is the same as the width of the bottom surface of the beam body.

5. The method for prestress reinforcement of a bridge without anchor devices according to claim 3, characterized in that In step S2, the surface treatment method is grinding or chiseling, and the surface treatment depth is not less than 5 mm.

6. The method for prestress reinforcement of a bridge without anchorages according to claim 5, characterized in that In step S5, the heating temperature is 50 - 500 °C.

7. The method for prestress reinforcement of a bridge without anchorages according to claim 5, characterized in that, In step S5, the heating temperature is 80 - 150 °C.

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