Strip type CFRP cloth hoop concrete beam

Abstract

The utility model discloses a strip type CFRP cloth hoop concrete beam which comprises CFRP longitudinal bars, CFRP cloth strips and steel stirrups. The CFRP cloth strips are made of carbon fiber cloth and epoxy resin glue and replace traditional steel bar stirrups to help concrete to resist shear, the three steel bar stirrups are arranged at the two ends and the midspan of a beam, only play a role in fixing a steel bar framework and have little help to structural stress, and the CFRP cloth strips are folded three times in the width direction to form a W-shaped section. A self-locking structure is formed through meshing of the wave crests and the wave troughs and vertically surrounds the outer sides of the longitudinal bars to form closed anti-shearing rings, and finally the CFRP cloth hoop steel bar framework is formed. Interface bonding is enhanced through folding self-locking and epoxy resin synergistically, the shear bearing capacity and corrosion resistance are remarkably improved, and the composite plate is suitable for corrosion environments such as ocean engineering and chemical engineering plants and has the advantages of being light in weight, easy to assemble and low in maintenance cost.

Description

Technical Field

[0001] This utility model relates to the internal steel reinforcement skeleton structure of concrete beams, belonging to the field of building engineering technology. Specifically, it uses CFRP strips to replace ordinary steel bars as stirrups for shear resistance, and folds them into strips with closed ends, forming a self-locking structure through the interlocking of crests and troughs. Background Technology

[0002] In conventional reinforced concrete beam structures, metal stirrups are susceptible to corrosion when exposed to humid, salt-corrosion, or chemically eroded environments for extended periods, leading to surface cracking and spalling of the concrete and significantly reducing the structure's lifespan. While using FRP (fiberglass reinforced plastic) composite materials for stirrups can improve corrosion resistance, the molding process requires prefabrication of specific curvatures, and stress concentration at the bending points can cause brittle fracture. Current construction methods require manual on-site fixing of stirrups, involving complex binding procedures and the use of easily corroded metal ties. Frequent repairs of corroded metal components further increase maintenance costs, hindering the sustainable development of building structures.

[0003] In current engineering practice, CFRP fabric is mostly used externally for shear reinforcement of beams. There is no technical solution to directly replace the built-in steel reinforcement and stirrups with folded CFRP fabric. The existing external application process generally adopts a planar layer-by-layer laying method, which lacks the optimization design of the fabric shape and reduces the utilization rate of materials. Summary of the Invention

[0004] This invention provides a strip-type CFRP fabric-stirred concrete beam. This structure uses lightweight and high-strength composite materials. Through the self-locking of the CFRP fabric strips at the crests and troughs and the bonding with epoxy resin, stress concentration at the bending points of the structure is effectively reduced. It is particularly suitable for working environments with strong corrosive media, such as marine engineering and chemical industrial buildings.

[0005] The technical solution adopted in this utility model is: a strip-type CFRP (Carbon Fiber Reinforced Plastics) reinforced concrete beam, including a beam body, CFRP longitudinal reinforcement, CFRP strips and steel stirrups;

[0006] The CFRP longitudinal reinforcement is continuously arranged along the entire length of the beam. The beam includes a single layer of CFRP longitudinal reinforcement at the top and a double layer of CFRP longitudinal reinforcement at the bottom. The CFRP longitudinal reinforcement is arranged in the upper and lower regions of the beam, respectively.

[0007] The CFRP strips are arranged vertically inside the beam and wrapped around the CFRP longitudinal reinforcement, forming a closed loop on the same side. The CFRP strips include carbon fiber cloth and an epoxy resin layer, with the epoxy resin layer disposed on the outermost surface of the carbon fiber cloth.

[0008] The CFRP strip is folded three times along its width, forming a W-shaped cross-section.

[0009] The steel stirrups are arranged at both ends and mid-span of the beam, with the steel stirrups at both ends of the beam 20-30mm away from the beam ends.

[0010] Preferably, the CFRP strip has W-shaped crests and troughs aligned and interlocked at the junction of the folded strips to form a self-locking structure.

[0011] Preferably, the CFRP strip is reinforced with epoxy resin adhesive at the folded junction.

[0012] Preferably, the CFRP strips are densified at the ends of the beam with a spacing of 80-100mm, and the spacing in other areas is 120mm.

[0013] Preferably, the steel stirrups are made of HPB300 steel bars, but they only serve to fix the CFRP stirrup frame and do not participate in the structural stress.

[0014] The beneficial effects of this utility model are:

[0015] 1. By using CFRP strip materials to replace traditional stirrups to bear the shear resistance, and selecting fiber composite materials as longitudinal reinforcing materials, the self-weight of the structure can be significantly reduced, making it easier to transport and assemble.

[0016] 2. Compared with traditional reinforced concrete components, this structure effectively improves shear resistance and corrosion resistance through the application of composite materials, and can be applied to engineering applications in harsh working conditions such as coastal facilities and chemically corrosive areas.

[0017] 3. Folding the CFRP fabric and aligning the crests with the troughs through friction self-locking not only achieves multi-layer stacking to improve the ultimate load-bearing capacity of the component, but also enhances the bonding effect at the interface, without completely relying on epoxy resin adhesive. Attached Figure Description

[0018] Figure 1 This is a diagram of the internal skeleton of the strip-type CFRP cloth-hoop concrete beam of this utility model.

[0019] Figure 2 This is a schematic diagram of the cross-section of the CFRP strip of this utility model folded into a W shape.

[0020] Figure 3 This is a schematic diagram of the CFRP fabric strip of this utility model after being folded and self-locking.

[0021] Figure 4 This is a detailed cross-sectional view of the junction of the CFRP strips of this utility model.

[0022] Reference numerals: 1. CFRP fabric strip; 2. CFRP longitudinal reinforcement; 3. Steel stirrup; 4. Epoxy resin layer; 5. Folded junction of the fabric strip. Detailed Implementation

[0023] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0024] See Figure 1-4 As shown, a strip-type CFRP reinforced concrete beam includes a beam body, CFRP longitudinal reinforcement 2, CFRP strips 1, and steel stirrups 3;

[0025] The CFRP longitudinal reinforcement 2 is continuously arranged along the entire length of the beam. The beam includes a single layer of CFRP longitudinal reinforcement 2 at the top and a double layer of CFRP longitudinal reinforcement 2 at the bottom. The CFRP longitudinal reinforcement 2 is respectively arranged in the upper and lower regions of the beam.

[0026] The CFRP strip 1 is arranged vertically in the beam body and wrapped around the CFRP longitudinal reinforcement 2, forming a closed loop on the same side. The CFRP strip 1 includes carbon fiber cloth and epoxy resin layer 4, with epoxy resin layer 4 disposed on the outermost surface of the carbon fiber cloth.

[0027] The CFRP strip 1 is folded three times along its width, forming a W-shaped cross-section;

[0028] The steel stirrups 3 are arranged at both ends and the middle of the beam, with the steel stirrups 3 at both ends of the beam 20-30mm away from the ends of the beam.

[0029] The CFRP fabric strips 1 have W-shaped crests and troughs aligned and interlocked at the folded junction 5, forming a self-locking structure. The CFRP fabric strips 1 are reinforced with epoxy resin at the folded junction 5. The CFRP fabric strips 1 are densified at the beam ends with a spacing of 80-100mm, and spaced 120mm in other areas. The steel stirrups 3 are made of HPB300 steel bars, but only serve to fix the CFRP fabric stirrup framework and do not participate in structural stress.

[0030] The fabrication method of the above-mentioned strip-type CFRP reinforced concrete beam includes the following steps.

[0031] Step 1: Erect CFRP longitudinal reinforcement 2 using steel stirrups 3. The steel stirrups 3 are divided into three parts: the two ends of the beam and the middle of the span. The CFRP longitudinal reinforcement 1 is arranged in two rows at the bottom and one row at the top.

[0032] Step 2: Cut CFRP strip 1. Cut 100-120mm in width and long enough to wrap around the top and bottom longitudinal reinforcement bars, leaving 100mm for anchoring lap.

[0033] Step 3: After folding CFRP strip 1 into four smaller sections, each layer should be 25-30mm wide, with a 50mm margin at both ends along the height direction. Apply epoxy resin to the remaining areas to facilitate subsequent overlapping. The folded carbon fiber fabric will bond better with the glue.

[0034] Step 4: Wrap the cut and folded CFRP fabric strip 1 around the CFRP longitudinal rib 2, with the ends of the strip aligned... Figure 2-4 The method shown is self-locking, which uses the W-shaped peaks at both ends to align and interlock with the troughs. After self-locking, epoxy resin is repeatedly applied to the junction of the folded strips to enhance the bonding performance.

[0035] Step 5: Let the coated and overlapped CFRP strip 1 stand for 24 hours to harden and form a CFRP band.

[0036] Step 6: Pour concrete using a standard rectangular concrete beam formwork. During the pouring process, use a vibrator to compact the concrete to prepare for subsequent testing and evaluation of the material's compressive strength, modulus of elasticity, and other performance indicators.

[0037] Step 7: Remove the template 24 hours after the specimen is formed, and use indoor curing conditions in winter for 28 days.

[0038] The specific embodiments described above further illustrate the purpose and technical solution of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the protection scope of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A strip-type CFRP (Crystal Reinforced Plastic) reinforced concrete beam, characterized in that: This includes the beam structure, CFRP longitudinal reinforcement, CFRP strips, and steel stirrups; The CFRP longitudinal reinforcement is continuously arranged along the entire length of the beam. The beam includes a single layer of CFRP longitudinal reinforcement at the top and a double layer of CFRP longitudinal reinforcement at the bottom. The CFRP longitudinal reinforcement is arranged in the upper and lower regions of the beam, respectively. The CFRP strips are arranged vertically inside the beam and wrapped around the CFRP longitudinal reinforcement, forming a closed loop on the same side. The CFRP strips include carbon fiber cloth and an epoxy resin layer, with the epoxy resin layer disposed on the outermost surface of the carbon fiber cloth. The CFRP strip is folded three times along its width, forming a W-shaped cross-section. The steel stirrups are arranged at both ends and mid-span of the beam, with the steel stirrups at both ends of the beam 20-30mm away from the beam ends.

2. The strip-type CFRP reinforced concrete beam according to claim 1, characterized in that: The CFRP strips at the junction of the folded sections have W-shaped crests and troughs that align and interlock to form a self-locking structure.

3. A strip-type CFRP reinforced concrete beam according to claim 2, characterized in that: The CFRP strips are reinforced with epoxy resin adhesive at the folded junction.

4. A strip-type CFRP reinforced concrete beam according to claim 3, characterized in that: The CFRP strips are densified at the ends of the beam with a spacing of 80-100mm, and the spacing in other areas is 120mm.

5. A strip-type CFRP reinforced concrete beam according to claim 4, characterized in that: The steel stirrups are made of HPB300 steel bars.

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