Multi-layer prestress tensioning reinforcing system and construction method thereof

Abstract

The invention provides a multi-layer prestress tension reinforcing system and a construction method thereof, the multi-layer prestress tension reinforcing system comprises a plurality of layers of carbon fiber plates applied with prestress, and the carbon fiber plates are sequentially stacked and anchored on the surface of a beam body needing to be reinforced; wherein the length of each layer of carbon fiber plate is gradually increased layer by layer from the inner layer to the outer layer, so that anchoring points, formed on the surface of the beam body, of the two ends of each layer of carbon fiber plate are sequentially distributed in a staggered mode. According to the multi-layer prestress tensioning reinforcing system and the construction method thereof, the problem that local stress of a beam body is excessively concentrated due to the fact that anchoring points are concentrated together can be solved; by means of the mode that all the layers of carbon fiber plates are tensioned and anchored layer by layer, the problem that the load needed by overall tensioning of the multiple layers of carbon fiber plates is too large can be avoided, and therefore the load and occupied space of a tensioning tool can be reduced so as to meet the requirement for tensioning and reinforcing construction of the multiple layers of carbon fiber plates of a large-span and narrow-width beam body, and the reinforcing reliability of the beam body is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of building reinforcement, and in particular relates to a multi-layer prestressed tensioning reinforcement system and a construction method thereof. Background Art

[0002] In recent years, prestressed carbon fiber plate reinforcement technology has been widely used in the reinforcement of buildings such as bridges. However, for some large buildings and beam structures with ultra-long spans, the cross-section of a single-layer carbon fiber plate often does not meet the cross-sectional area required for reinforcement when using this technology for reinforcement. Therefore, multi-layer prestressed carbon fiber plate reinforcement technology came into being. This technology greatly increases the number of prestressed carbon fiber plates that can be arranged in a limited space by using a set of anchor systems to tension multiple carbon fiber plates.

[0003] At present, the commonly used multi-layer prestressed carbon fiber plate anchors are installed by fixing multiple carbon fiber plates at the same position of the beam body. Since this method requires the simultaneous tensioning of multiple carbon fiber plates, the tensioning tooling needs to have a high load output capacity, which results in a large space occupied by the tensioning tooling. For the beam structure with an ultra-long span, there is a problem of limited installation space during construction, which also leads to a low upper limit on the number of carbon fiber plate layers. In addition, the anchors concentrated at the same position of the beam body will cause excessive local force concentration on the beam body, which will have an adverse effect on the reliability of the beam body. Summary of the invention

[0004] The embodiment of the present invention provides a multi-layer prestressed tensioning reinforcement system and a construction method thereof, aiming to solve the problem of being limited by beam space during the construction process of multi-layer prestressed carbon fiber plate tensioning reinforcement and improve the reliability of beam reinforcement.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: in the first aspect, a multi-layer prestressed tensioning reinforcement system is provided, comprising a plurality of layers of carbon fiber plates to which prestress is applied, wherein each layer of the carbon fiber plates is sequentially stacked and anchored on the surface of a beam body to be reinforced; wherein the length of each layer of the carbon fiber plates increases gradually from the inner layer to the outer layer, so that the anchoring points formed at the two ends of each layer of the carbon fiber plates on the surface of the beam body are sequentially staggered and distributed.

[0006] In combination with the first aspect, in a possible implementation manner, the prestress applied to each layer of the carbon fiber board decreases layer by layer from the inner layer to the outer layer.

[0007] In some embodiments, anchor plates are provided at both ends of the carbon fiber plate, and the anchor plates are anchored and fixed to grooves provided on the surface of the beam body.

[0008] Exemplarily, the outer surface of the anchor plate is flush with the surface of the beam body, and a bevel is provided on one edge of the groove facing the middle of the carbon fiber plate, and the end of the carbon fiber plate abuts against the bevel to form an arc shape.

[0009] The multi-layer prestressed tensioning reinforcement system provided by the present invention has the beneficial effect that: compared with the prior art, the multi-layer prestressed tensioning reinforcement system of the present invention adopts a method of stacking and anchoring multiple layers of carbon fiber plates in sequence, and the length of each layer of carbon fiber plate increases layer by layer from the inner layer to the outer layer, which can make the anchor points of each layer of carbon fiber plate on the surface of the beam body dislocated and dispersed, thereby avoiding the problem of excessive local force concentration on the beam body caused by the anchor points being concentrated together, thereby avoiding the situation where the prestressed tensioning reinforcement fails due to damage to the structure of the beam body itself, and improving the reliability of the multi-layer prestressed tensioning reinforcement system; in addition, during construction, a single-layer tensioning tool can be used to apply tensioning prestress to each layer of carbon fiber plate layer by layer, thereby, on the one hand, avoiding the problem of excessive load required for overall tensioning, thereby reducing the load and space occupation of the tensioning tool to be suitable for the tensioning reinforcement construction requirements of multi-layer carbon fiber plates for beams with large spans and narrow widths, and on the other hand, it can also avoid the problem of high upper limit of the number of layers for synchronous tensioning of multi-layer carbon fiber plates, thereby increasing the number of layers of carbon fiber plates to increase the overall tensioning prestress, thereby improving the prestressing tensioning reinforcement effect.

[0010] In a second aspect, an embodiment of the present invention further provides a construction method of a multi-layer prestressed tension reinforcement system, comprising: Step S100, determining the installation position of the carbon fiber plate and positioning and laying out the lines according to the installation positions of the anchor plates at both ends of each layer of the carbon fiber plate; Step S200, performing base surface processing according to the installation position of the carbon fiber plate and performing drilling and reinforcing bar planting based on the positioning and laying-out position, and then installing an anchor plate, the anchor plate being used to anchor the end of the carbon fiber plate and to be used for detachably connecting the tensioning tooling; Step S300, determining whether the tensioning method of the carbon fiber plate is single-end tensioning or double-end tensioning; Step S400: if the tensioning method is single-end tensioning, one end of the innermost carbon fiber plate is anchored to the anchor plate at its fixed end, and the other end is connected to the tensioning tooling; if the tensioning method is double-end tensioning, the two ends of the innermost carbon fiber plate are respectively connected to a tensioning tooling; Step S500, applying adhesive to the innermost carbon fiber plate and applying prestressing force to it through a tensioning tool; Step S600, anchoring the tensioning end of the innermost carbon fiber plate to the corresponding anchor plate, and removing the tensioning tooling after the adhesive is cured; Step S700, repeating steps 400 to S600 until the anchoring of the outermost carbon fiber plate is completed, thereby obtaining the above-mentioned multi-layer prestressed tensioning reinforcement system.

[0011] In combination with the second aspect, in some embodiments, in step S200, grooves are opened on the surface of the beam body at the installation position of each anchor plate for the anchor plate to be embedded and installed, and a slope is set on the edge of each groove facing the middle of the carbon fiber plate, so that after the carbon fiber plate obtains prestressing in step S500, its end forms an arc shape that is against the slope.

[0012] In some embodiments, before step S500, the method further includes: determining that the tension prestress required to be applied to each layer of carbon fiber board decreases layer by layer, and calculating the tension force value required to be additionally applied to each layer of carbon fiber board relative to the outermost layer of carbon fiber board.

[0013] Exemplarily, calculating the additional tensile force value that needs to be applied to each layer of the carbon fiber plate relative to the outermost layer of the carbon fiber plate includes: Calculate the neutral plane position and moment of inertia I after installing the nth layer of carbon fiber board according to the shape and material of the beam n and the average modulus E of the tension zone n ; Determine the distance between the center of the thickness of the n+1th carbon fiber plate and the neutral plane as X n+1 , and determine the prestressing force that needs to be applied to the n+1th layer of carbon fiber plate is F n+1 , obtain the bending moment M of the n+1th carbon fiber plate on the beam n+1 =F n+1 ×X n+1 ; According to the moment of inertia I n , the average modulus E of the tension zone n , bending moment M n+1 =F n+1 ×X n+1 The reduction values ​​of the prestressing stress of the first n layers of carbon fiber plates caused by tensioning the n+1th layer of carbon fiber plates are calculated as F1≈F2≈……F n =E f S n X n M n+1 / E n I n , denoted as F' n+1 ; Among them, E f is the elastic modulus of the carbon fiber plate, S n is the cross-sectional area of ​​the nth layer of carbon fiber plate; Calculate the additional tensile force f required for the nth layer of carbon fiber plate n = F' n+1 + F' n+2 +……+ F' m , where m is the total number of layers of the carbon fiber board.

[0014] For example, the moment of inertia I n = ; Average modulus E of the tension zone n = ;in, is the area differential of the nth carbon fiber plate, y is the distance between the area differential and the neutral plane, E c is the elastic modulus of the beam concrete, E s is the elastic modulus of the beam reinforcement, A c is the concrete cross-sectional area in the tension zone, A s is the cross-sectional area of ​​the steel bars in the tension zone, A f is the cross-sectional area of ​​the carbon fiber plate in the tension zone.

[0015] In some embodiments, the anchor plate is provided with anchor holes suitable for the carbon fiber plate to pass through, and both ends of the carbon fiber plate are anchored to the corresponding anchor holes respectively.

[0016] The construction method of the multi-layer prestressed tensioning reinforcement system provided by the present invention has the beneficial effect that: compared with the prior art, the construction method of the multi-layer prestressed tensioning reinforcement system of the present invention adopts a method of tensioning and anchoring each layer of carbon fiber plate from the inner layer to the outer layer layer by layer, and utilizes the length difference of each layer of carbon fiber plate to make the anchor plates at the ends of each layer of carbon fiber plate staggered on the surface of the beam body, thereby avoiding the situation where the local force of the beam body is too concentrated and the structure is damaged, and improving the reliability of the multi-layer prestressed tensioning reinforcement system; a single-layer detachable tensioning tool is used to apply tensioning prestress to each layer of carbon fiber plate layer by layer, thereby on the one hand, it can avoid the problem of excessive load required for overall tensioning, thereby reducing the load and space occupation of the tensioning tool to be suitable for the tensioning reinforcement construction requirements of multi-layer carbon fiber plates for beams with large spans and narrow widths, and on the other hand, it can also avoid the problem of high upper limit of the number of layers for synchronous tensioning of multi-layer carbon fiber plates, thereby increasing the number of layers of carbon fiber plates to increase the overall tensioning prestress, thereby improving the prestressing tensioning reinforcement effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of a multi-layer prestressed tensioning reinforcement system provided in an embodiment of the present invention.

[0018] In the figure: 10, carbon fiber plate; 20, anchor plate; 30, beam surface. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] It should be noted that when an element is referred to as being "disposed on" or "connected to" another element, it may be directly on the other element or indirectly on the other element. It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "multi-layer" means two or more layers, unless otherwise clearly and specifically defined.

[0021] See also Figure 1 The multi-layer prestressed tension reinforcement system provided by the present invention is now described. The multi-layer prestressed tension reinforcement system comprises a plurality of carbon fiber plates 10 to which prestress is applied, and each layer of carbon fiber plates 10 is sequentially stacked and anchored on the beam surface 30 to be reinforced; wherein the length of each layer of carbon fiber plates 10 increases layer by layer from the inner layer to the outer layer, so that the anchoring points formed by the two ends of each layer of carbon fiber plates 10 on the beam surface 30 are sequentially staggered and distributed.

[0022] It should be noted that in this embodiment, the innermost carbon fiber plate 10 and the beam body surface 30, as well as the adjacent carbon fiber plates 10 are fixed by adhesive; each layer of carbon fiber plate 10 is subjected to a tensioning tool to apply tensioning prestress before the adhesive on its inner surface is cured, and the tensioning state is maintained until the adhesive is cured before the tensioning tool can be removed; the center lines of the length direction of each layer of carbon fiber plate 10 are aligned, and based on the length increasing layer by layer from the inside to the outside, the two ends of the outer carbon fiber plate 10 can be located outside the two ends of the inner carbon fiber plate 10, thereby Then, a structure is formed in which the outer carbon fiber plate 10 entirely covers the inner carbon fiber plate 10, so that the anchoring points of each layer of carbon fiber plate 10 and the beam surface 30 are staggered and distributed at intervals, thereby avoiding the concentration of force on the beam; at the same time, since the inner carbon fiber plate 10 protrudes from the beam surface 30, the outer carbon fiber plate 10 will form an arch relative to the beam surface 30 based on the support of the inner carbon fiber plate 10, thereby enabling the middle part of the carbon fiber plate 10 to form an upward force (close to the direction of the beam surface 30) on the beam, thereby improving the bearing capacity of the beam in the middle span.

[0023] The multi-layer prestressed tensioning reinforcement system provided in this embodiment, compared with the prior art, adopts a method of stacking and anchoring multiple layers of carbon fiber plates 10 in sequence, and the length of each layer of carbon fiber plate 10 increases layer by layer from the inner layer to the outer layer, which can make the anchor points of each layer of carbon fiber plate 10 on the beam surface 30 staggered and dispersed, thereby avoiding the problem of excessive local force concentration on the beam body caused by the anchor points being concentrated together, thereby avoiding the situation where the prestressed tensioning reinforcement fails due to damage to the structure of the beam body itself, and improving the reliability of the multi-layer prestressed tensioning reinforcement system; in addition, during construction, a single-layer tensioning tool can be used to apply tensioning prestress to each layer of carbon fiber plate 10 layer by layer, thereby, on the one hand, avoiding the problem of excessive load required for overall tensioning, thereby reducing the load and space occupation of the tensioning tool to be suitable for the tensioning reinforcement construction requirements of the multi-layer carbon fiber plate 10 for the beam body with a large span and a narrow width, and on the other hand, it can also avoid the problem of high upper limit of the number of layers for the synchronous tensioning of the multi-layer carbon fiber plate 10, thereby increasing the number of layers of the carbon fiber plate 10 to increase the overall tensioning prestress, thereby improving the prestressing tensioning reinforcement effect.

[0024] In some embodiments, the prestress applied to each layer of the carbon fiber plate 10 decreases layer by layer from the inner layer to the outer layer. Since the prestress applied to the outer layer of the carbon fiber plate 10 will cause a partial loss of the prestress on the inner layer of the carbon fiber plate 10, if the same prestress is applied to each layer of the carbon fiber plate 10, the carbon fiber plate 10 closer to the outer layer will be subjected to a higher force after the final reinforcement is completed, thereby causing the rated tensile load redundancy of the inner layer of the carbon fiber plate 10 and the outer layer of the carbon fiber plate 10 to be easily overloaded and broken. In order to avoid the above situation, a higher prestress is applied to the carbon fiber plate 10 that is first tensioned and anchored in the inner layer, and the prestress applied when the remaining carbon fiber plates 10 are tensioned outward layer by layer is reduced layer by layer, and the prestress of the inner layer of the carbon fiber plate 10 is used to compensate the prestress of the outer layer of the carbon fiber plate 10, so that the prestress of each layer of the carbon fiber plate 10 is finally consistent, thereby improving the tension reinforcement stability of the multi-layer carbon fiber plate 10.

[0025] As a specific embodiment of the carbon fiber plate 10, please refer to Figure 1 , anchor plates 20 are provided at both ends of the carbon fiber plate 10, and the anchor plates 20 are anchored and fixed to the grooves provided on the beam surface 30. By providing a groove on the beam surface 30 and embedding the anchor plates 20 into the grooves, the bottom of the grooves can be punched with holes to plant reinforcement to fix the anchor plates 20, and the two ends of the carbon fiber plate 10 and the anchor plates 20 can be connected by mechanical anchoring or chemical anchoring, thereby improving the anchoring stability of each layer of the carbon fiber plate 10 by utilizing the limiting effect of the grooves on the anchor plates 20.

[0026] Specifically, the anchor plate 20 used at the tensioning end has an anchor hole suitable for the end of the carbon fiber plate 10 to pass through. A wedge-shaped anchor sheet can be arranged in the anchor hole to clamp the carbon fiber plate 10 and anchor the tensioning end of the carbon fiber plate 10 after the tensioning is completed. Alternatively, adhesive can be applied when the carbon fiber plate 10 passes through the anchor hole, tensioning is completed before the adhesive is cured, and the tensioning prestress is maintained until the adhesive is cured. The anchor plate 20 used at the fixed end can be directly clamping the fixed end of the carbon fiber plate 10 on the beam surface 30. Of course, the fixed end of the carbon fiber plate 10 should be coated with adhesive (epoxy or acrylic) for bonding to form a chemical anchor, or clamped by a wedge-shaped anchor sheet to form a mechanical anchor.

[0027] For some possible implementations, see Figure 1 The outer surface of the anchor plate 20 is flush with the beam surface 30, and a bevel is provided on one side edge of the groove facing the middle of the carbon fiber plate 10, and the end of the carbon fiber plate 10 abuts against the bevel to form an arc shape. The bevel can prevent the carbon fiber plate 10 from being subjected to the shear force of the edge of the groove, and at the same time, the bevel supports the carbon fiber plate 10 so that the two ends of the carbon fiber plate 10 form an arc shape, thereby forming an arch shape as a whole. In this way, after the carbon fiber plate 10 is tensioned and prestressed, the middle part of the carbon fiber plate 10 can form a force towards the neutral plane of the beam body, thereby improving the bearing capacity of the mid-span of the beam body after tension reinforcement.

[0028] Based on the same inventive concept, combined Figure 1 The present application also provides a method for constructing a multi-layer prestressed tension reinforcement system, comprising: Step S100, determine the installation position of the carbon fiber board 10 and perform positioning and laying out according to the installation position of the anchor plates 20 at both ends of each layer of the carbon fiber board 10. Specifically, the installation position of the carbon fiber board 10 is determined according to the design drawing, and the center line position of the carbon fiber board 10 is determined, so as to determine the installation position of the anchor plates 20 at both ends of each layer of the carbon fiber board 10 according to the length of each layer of the carbon fiber board 10.

[0029] Step S200, perform base surface treatment according to the installation position of the carbon fiber plate 10, perform drilling and planting of reinforcement based on the positioning and laying-out position, and then install the anchor plate 20, which is used to anchor the end of the carbon fiber plate 10 and is used for detachable connection of the tensioning tooling. Specifically, the base surface treatment includes grinding the beam surface 30, removing the loose layer of concrete and dirt, and leveling the uneven position of the beam surface 30; a groove with the same thickness as the anchor plate 20 is opened at the position where the anchor plate 20 is installed, and then the anchor plate 20 is embedded in the groove for fixing after drilling holes and planting reinforcement at the bottom of the groove. After fixing, the outer surface of the anchor plate 20 is flush with the beam surface 30 (the surface after base surface treatment), so that the outer carbon fiber plate 10 can cover the inner carbon fiber plate 10 and the anchor plates 20 at both ends as a whole.

[0030] Step S300, determining whether the tensioning mode of the carbon fiber plate 10 is single-end tensioning or double-end tensioning. Specifically, the single-end tensioning mode and double-end tensioning mode of the carbon fiber plate 10 are determined based on the reinforcement design requirements. Usually, when the carbon fiber plate 10 is long, double-end tensioning is used to ensure that the overall force of the carbon fiber plate 10 is balanced.

[0031] Step S400, if the tensioning method is single-end tensioning, one end of the innermost carbon fiber plate 10 is anchored to the anchor plate 20 at its fixed end, and the other end is connected to the tensioning tool. Specifically, the carbon fiber plate 10 and the anchor plate 20 at its fixed end can be chemically anchored or mechanically anchored. Here, the surface of the fixed end of the carbon fiber plate 10 can be roughened by sandpapering or sandblasting, and then coated with adhesive or clamped between wedge-shaped anchor plates and pressed against the inner side of the anchor plate 20; the tensioning tool can be located at the anchor plate 20 at the tensioning end of the carbon fiber plate 10 as an installation base, and the tensioning tool can be connected to the tensioning end of the carbon fiber plate 10 by chemical anchoring or mechanical anchoring. It should be noted that the tensioning end of the carbon fiber plate 10 can be connected to the tensioning tool after passing through the anchor hole pre-opened on the inner side of the anchor plate 20 or the middle part of the anchor plate 20.

[0032] If the tensioning method is double-end tensioning, the two ends of the innermost carbon fiber plate 10 are connected to a tensioning tool respectively. During double-end tensioning, the anchor plates 20 at both ends of the carbon fiber plate 10 are connected to a tensioning tool respectively, and then the two ends of the carbon fiber plate 10 are respectively passed through the inner side of the corresponding anchor plate 20 or the anchor holes pre-opened in the middle of the anchor plate 20 and connected to the tensioning tool. Of course, if the carbon fiber plate 10 and the anchor plate 20 are chemically anchored, adhesive should be applied to the part where the carbon fiber plate 10 passes through the anchor plate 20.

[0033] Step S500, apply prestressing force to the innermost carbon fiber plate 10 after applying adhesive to it through a tensioning tool. The adhesive on the carbon fiber plate 10 is in an uncured state during the tensioning process, and the tensioning process can be carried out in a graded tensioning manner until the designed tensioning force value is reached.

[0034] Step S600, anchoring the tensioning end of the innermost carbon fiber plate 10 to the corresponding anchor plate 20, and removing the tensioning tool after the adhesive is cured. Specifically, after the tensioning prestress applied by the tensioning tool reaches the design value, the tensioning end of the carbon fiber plate 10 and the anchor plate 20 can be fixed by chemical anchoring or mechanical anchoring, and then the tensioning tool can be removed. Before removal, the carbon fiber plate 10 can be cut off at the position between the tensioning tool and the anchor plate 20 to avoid the presence of protruding excess material at the tensioning end of the carbon fiber plate 10 and affecting the flatness of the outer carbon fiber plate 10.

[0035] Step S700, repeat steps 400 to S600 until the anchoring of the outermost carbon fiber plate 10 is completed, and the above-mentioned multi-layer prestressed tensioning reinforcement system is obtained. Specifically, before each layer of carbon fiber plate 10 is tensioned, the uneven position existing after the anchoring of the previous layer of carbon fiber plate 10 should be repaired and leveled. After all the carbon fiber plates 10 are tensioned and anchored, anti-corrosion protection treatment should also be carried out. Specifically, the anchor plate 20 and other metal parts such as anchor bolts should be painted with anti-corrosion paint or sealed with concrete or mortar. The surface of the carbon fiber plate 10 should be coated with polyurethane topcoat or epoxy topcoat for protection, or sealed with mortar or concrete.

[0036] Compared with the prior art, the construction method of the multi-layer prestressed tensioning reinforcement system provided by the present invention adopts a method of tensioning and anchoring each layer of carbon fiber plate 10 from the inner layer to the outer layer layer by layer, and utilizes the length difference of each layer of carbon fiber plate 10 to make the anchor plate 20 at the end of each layer of carbon fiber plate 10 staggered on the beam surface 30, thereby avoiding the situation where the local force of the beam body is too concentrated and the structure is damaged, and improving the reliability of the multi-layer prestressed tensioning reinforcement system; a single-layer detachable tensioning tool is used to apply tensioning prestress to each layer of carbon fiber plate 10 layer by layer, thereby on the one hand, it can avoid the problem of excessive load required for overall tensioning, thereby reducing the load and space occupation of the tensioning tool to be suitable for the tensioning reinforcement construction requirements of multi-layer carbon fiber plates 10 for beams with large spans and narrow widths, and on the other hand, it can also avoid the problem of high upper limit of the number of layers for synchronous tensioning of multi-layer carbon fiber plates 10, thereby increasing the number of layers of carbon fiber plates 10 to increase the overall tensioning prestress, thereby improving the prestressed tensioning reinforcement effect.

[0037] Combined with the second aspect, combined Figure 1 It is understood that in some embodiments, in step S200, grooves are provided on the beam surface 30 at the installation position of each anchor plate 20 for the anchor plate 20 to be embedded and installed, and a bevel is provided on the edge of each groove facing the middle of the carbon fiber plate 10, so that after the carbon fiber plate 10 obtains the prestressing in step S500, its end forms an arc shape that abuts against the bevel.

[0038] By providing the groove, on the one hand, the connection part between the carbon fiber plate 10 and the anchor plate 20 can be prevented from being subjected to shear stress; on the other hand, the carbon fiber plate 10 can be extended outward along the slope from the position of the anchor plate 20 embedded in the groove to form an arc shape, so that the carbon fiber plate 10 is in a state of arch tension as a whole, thereby utilizing the tension prestress to generate a force on the beam body toward the neutral plane of the beam body, thereby improving the mid-span bearing capacity of the beam body.

[0039] It should be noted that before step S500, it also includes: determining that the tension prestress required to be applied to each layer of carbon fiber plate 10 is reduced layer by layer, and calculating the tension force value that needs to be additionally applied to each layer of carbon fiber plate 10 relative to the outermost carbon fiber plate 10. This step can be performed when designing the tension reinforcement scheme of the beam body. By determining the tension prestress of each layer of carbon fiber plate 10, the inner layer of carbon fiber plate 10 can compensate for the tension prestress difference of the outer layer of carbon fiber plate 10, so that the tension prestress loss of the inner layer of carbon fiber plate 10 caused by the tensioning of the outer layer of carbon fiber plate 10 can be utilized, and the tension prestress of each layer of carbon fiber plate 10 is finally formed to be consistent, avoiding the situation that the rated tension load of the inner layer of carbon fiber plate 10 is redundant and the tension overload of the outer layer of carbon fiber plate 10 occurs after the tensioning is completed, thereby improving the tension reinforcement reliability of the multi-layer carbon fiber plate 10.

[0040] Exemplarily, calculating the additional tension value that needs to be applied to each layer of the carbon fiber plate 10 relative to the outermost layer of the carbon fiber plate 10 includes: According to the shape and material of the beam, the neutral plane position and the moment of inertia I after installing the nth layer of carbon fiber plate 10 are calculated. n and the average modulus E of the tension zone n ; Determine the distance between the center of the thickness of the n+1th layer of carbon fiber plate 10 and the neutral plane as X n+1 , and determine that the tension prestressing force to be applied to the n+1th layer of carbon fiber plate 10 is F n+1 , obtain the bending moment M of the n+1th carbon fiber plate 10 on the beam n+1 =F n+1 ×X n+1 ; According to the moment of inertia I n , the average modulus E of the tension zone n , bending moment M n+1 =F n+1 ×X n+1 The reduction values ​​of the tension prestress of the first n layers of carbon fiber plates 10 caused by tensioning the n+1th layer of carbon fiber plate 10 are calculated as F1≈F2≈……F n =E f S n X n M n+1 / E n I n , denoted as F' n+1 ; Among them, E f is the elastic modulus of the carbon fiber plate 10, S n is the cross-sectional area of ​​the nth layer of carbon fiber plate 10; Calculate the additional tensile force value f required for the nth layer of carbon fiber plate 10 n = F' n+1 + F' n+2+……+ F' m , wherein m is the total number of layers of the carbon fiber board 10.

[0041] For example, the moment of inertia I n = ; Average modulus E of the tension zone n = ;in, is the area differential of the nth layer of carbon fiber board 10, y is the distance between the area differential and the neutral plane, E c is the elastic modulus of the beam concrete, E s is the elastic modulus of the beam reinforcement, A c is the concrete cross-sectional area in the tension zone, A s is the cross-sectional area of ​​the steel bars in the tension zone, A f is the cross-sectional area of ​​the carbon fiber plate 10 in the tension zone.

[0042] It should be understood that the anchor plate 20 is provided with an anchor hole suitable for the carbon fiber plate 10 to pass through, and the two ends of the carbon fiber plate 10 are respectively anchored in the corresponding anchor holes. The anchor hole can be a wedge-shaped hole, which cooperates with the wedge-shaped anchor pieces clamped on both sides of the carbon fiber plate 10 to achieve the anchoring of the carbon fiber plate 10, and has the effect that the higher the tension value, the greater the clamping force. At the same time, the wedge-shaped anchor piece can be coated with adhesive during anchoring, thereby further improving the anchoring reliability and reducing the risk of unanchoring.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Multi-layer prestressed tension reinforcement system, characterized in that: It comprises multiple layers of prestressed carbon fiber plates, wherein each layer of the carbon fiber plates is stacked and anchored in sequence on the surface of the beam body to be reinforced; wherein the length of each layer of the carbon fiber plates increases layer by layer from the inner layer to the outer layer, so that the anchoring points formed at the two ends of each layer of the carbon fiber plates on the surface of the beam body are staggered and distributed in sequence.

2. The multi-layer prestressed tension reinforcement system according to claim 1, characterized in that: The prestress applied to each layer of the carbon fiber plate decreases layer by layer from the inner layer to the outer layer.

3. The multi-layer prestressed tension reinforcement system according to claim 1, characterized in that: Anchor plates are provided at both ends of the carbon fiber plate, and the anchor plates are anchored and fixed to the grooves opened on the surface of the beam body.

4. The multi-layer prestressed tension reinforcement system according to claim 3, characterized in that: The outer surface of the anchor plate is flush with the surface of the beam body, and a slope is provided on one side edge of the groove facing the middle of the carbon fiber plate, and the end of the carbon fiber plate abuts against the slope to form an arc shape.

5. The construction method of the multi-layer prestressed tension reinforcement system is characterized in that: include: Step S100, determining the installation position of the carbon fiber plate and positioning and laying out the lines according to the installation positions of the anchor plates at both ends of each layer of the carbon fiber plate; Step S200, performing base surface treatment according to the installation position of the carbon fiber plate and performing drilling and reinforcing bar planting based on the positioning and laying-out position, and then installing the anchor plate, wherein the anchor plate is used to anchor the end of the carbon fiber plate and to be used to detachably connect the tensioning tooling; Step S300, determining whether the tensioning method of the carbon fiber plate is single-end tensioning or double-end tensioning; Step S400, if the tensioning method is single-end tensioning, one end of the innermost carbon fiber plate is anchored to the anchor plate at its fixed end, and the other end is connected to the tensioning tooling; If the tensioning method is double-end tensioning, two ends of the innermost carbon fiber plate are respectively connected to one of the tensioning tools; Step S500, applying adhesive to the innermost carbon fiber plate and applying prestressing force to it through the tensioning tool; Step S600, anchoring the tensioning end of the innermost carbon fiber plate to the corresponding anchor plate, and removing the tensioning tooling after the adhesive is cured; Step S700, repeating step 400 to step S600 until the anchoring of the outermost layer of the carbon fiber plate is completed, thereby obtaining the multi-layer prestressed tensioning reinforcement system according to any one of claims 1 to 4.

6. The construction method of the multi-layer prestressed tension reinforcement system according to claim 5, characterized in that: In the step S200, grooves are provided on the surface of the beam body at the installation positions of each anchor plate for the anchor plate to be embedded and installed, and a slope is provided on the edge of each groove toward the middle of the carbon fiber plate, so that after the carbon fiber plate obtains the tensioning prestress in the step S500, its end forms an arc shape that abuts against the slope.

7. The construction method of the multi-layer prestressed tension reinforcement system according to claim 5, characterized in that: Before step S500, the method further includes: determining that the tension prestressing force to be applied to each layer of the carbon fiber plate is reduced layer by layer, and calculating the tensioning force value to be additionally applied to each layer of the carbon fiber plate relative to the outermost layer of the carbon fiber plate.

8. The construction method of the multi-layer prestressed tension reinforcement system according to claim 7, characterized in that: The calculation of the additional tension value that needs to be applied to each layer of the carbon fiber plate relative to the outermost layer of the carbon fiber plate includes: According to the shape and material of the beam, the neutral plane position and moment of inertia I after installing the nth layer of carbon fiber plate are calculated. n and the average modulus E of the tension zone n ; Determine the distance between the thickness center of the carbon fiber plate of the n+1th layer and the neutral plane as X n+1 , and determine the prestressing force that needs to be applied to the carbon fiber plate of the n+1th layer as F n+1 , obtain the bending moment M of the carbon fiber plate on the beam body at the n+1th layer n+1 =F n+1 ×X n+1 ; According to the moment of inertia I n , the average modulus E of the tension zone n , the bending moment M n+1 =F n+1 ×X n+1 The reduction values ​​of the prestressing stress of the first n layers of the carbon fiber plate caused by tensioning the n+1th layer of the carbon fiber plate are calculated as F1≈F2≈……F n =E f S n X n M n+1 / E n I n , denoted as F' n+1 ; Among them, E f is the elastic modulus of the carbon fiber plate, S n is the cross-sectional area of ​​the carbon fiber plate of the nth layer; Calculate the additional tensile force f required for the nth layer of the carbon fiber plate n =F' n+1 + F' n+2 +……+ F' m , wherein m is the total number of layers of the carbon fiber board.

9. The construction method of the multi-layer prestressed tension reinforcement system according to claim 8, characterized in that: The moment of inertia I n = ; The average modulus E of the tension zone n = ;in, is the area differential of the nth layer of the carbon fiber plate, y is the distance between the area differential and the neutral plane, E c is the elastic modulus of the beam concrete, E s is the elastic modulus of the beam reinforcement, A c is the concrete cross-sectional area in the tension zone, A s is the cross-sectional area of ​​the steel bars in the tension zone, A f is the cross-sectional area of ​​the carbon fiber plate in the tension zone.

10. The construction method of the multi-layer prestressed tension reinforcement system according to any one of claims 5 to 9, characterized in that: The anchor plate is provided with anchor holes suitable for the carbon fiber plate to pass through, and both ends of the carbon fiber plate are anchored to the corresponding anchor holes respectively.

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