Carbon fiber confined steel tube concrete reinforced main arch ring of hollow arch bridge and its construction method

Abstract

The present invention relates to the technical field of bridge reinforcement, and in particular to a carbon fiber constrained steel tube concrete reinforced hollow arch bridge main arch ring and its construction method. The fiber constrained steel tube concrete reinforced hollow arch bridge main arch ring and its construction method described in the present invention include a row of steel tube arch ring layers arranged parallel to the bridge direction on the top surface of the arch ring between the columns, a fiber winding layer that wraps the steel tube arch ring and the original main arch ring together, and a unidirectional carbon fiber cloth layer laid along the length direction of the bridge on the bottom surface of the main arch ring; the steel tube arch ring is composed of a plurality of steel tube concretes arranged on the same axis and located on the top surface of the hollow section main arch ring between different columns; the roots of the two ends of the steel tube are connected by embedded steel bars preset on the adjacent structural components at both ends of the arch ring. This method not only gets rid of the problem of poor working conditions existing in the traditional arch bottom construction method, and the structural efficiency of the newly added structural layer is higher, but also has the characteristic of not destroying the original arch bottom structural characteristics, and has a wide range of applications.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge reinforcement, and in particular to a main arch ring reinforcement method for a deck-type hollow concrete arch bridge. Background Art

[0002] In recent years, a large number of bridges in my country have entered the maintenance period, and there is a large demand for bridge structure reinforcement. Among them, the older bottom-supported hollow arch bridge is one of the most common bridge types to be reinforced.

[0003] When designing this type of bridge reinforcement, the most commonly used reinforcement method is to increase the cross-section of the main arch ring. This method is mainly divided into two categories: main arch back reinforcement and main arch bottom reinforcement. The main arch bottom reinforcement method has a clear force distribution and will not cause serious arch structure safety hazards to the structural parts that have already experienced severe pressure line deviation due to the increase in construction load on the arch before the newly added structural parts have formed their bearing capacity. Therefore, it has a wider range of applications and has become the most mainstream main arch ring reinforcement method for top-decker hollow arch bridges. However, this method has four technical problems that need to be solved:

[0004] (1) There is an obvious stress hysteresis effect in the newly added structural part, and the structural efficiency of the new structural part is low;

[0005] (2) There are interface problems between the original main arch ring and the new structure, which puts forward higher requirements for construction quality;

[0006] (3) Because the entire construction section of the main arch bottom surface section increase method is constructed at a reverse angle, it places high demands on the construction organization, resulting in high measures costs and a long construction period;

[0007] (4) In addition, among the top-supported hollow arch bridges, there is a sub-type of bridge that is unique to my country and has a high historical preservation value - the hyperbolic arch bridge. The back of the main arch ring of this bridge type is equipped with horizontal and vertical bidirectional ribs and a curved wave arch, which constitutes its main feature and is also one of the key points of its historical preservation. Therefore, the method of increasing the cross-section of the bottom surface of the main arch cannot achieve the purpose of strengthening the bridge while maintaining cultural protection. Moreover, this type of bridge, due to its low original design load-bearing capacity and long service life, most of them need reinforcement.

[0008] It's worth noting that over the past two decades, carbon fiber bonding reinforcement technology has been widely used due to its ease of construction, significant improvement in tensile bearing capacity, adaptability to external shapes, and high durability. However, in arch bridge reinforcement, carbon fiber bonding is primarily used for tensile reinforcement, which significantly differs from the technical requirements of strengthening a typical small eccentric compressive member like the main arch ring, which ultimately aims to adjust the arch ring pressure line. Therefore, in most cases, it is only used as an auxiliary repair method for arch ring reinforcement, applied to repair local cracks in the arch ring or to improve the bending bearing capacity of areas with large bending moments.

[0009] In this situation, the arch back reinforcement method, a reinforcement technology that has been gradually less used, has attracted attention again because it is easier to ensure the connection between the new and old interfaces. At the same time, due to the self-weight of the new structure, the stress hysteresis effect is relatively weak, the new structure is more efficient, and the construction surface is at a positive angle, the working surface conditions are better, and it also has the cultural relic protection attribute of not destroying the original structural form of the bottom surface of the main arch ring. Therefore, if a method based on the principle of the arch back reinforcement method can be proposed, through the adjustment of construction measures, it can better solve the problem of instability of the damaged key structural sections of the original arch ring caused by segmented construction loads, and at the same time adopt more convenient construction measures to assist, it will effectively promote the advancement of bridge reinforcement construction technology and provide important technical means for the protection of cultural relics in my country's engineering construction. Summary of the Invention

[0010] The present invention aims to provide a carbon fiber constrained steel tube concrete main arch ring reinforcement system and a construction method thereof.

[0011] The technical problems to be solved are: the difficulty of arch bottom construction in traditional arch bottom construction methods, the interface between new and old structures, and the structural efficiency of the new structure.

[0012] In order to solve the above technical problems, the present invention adopts the following technical solutions: a carbon fiber constrained steel tube concrete arch ring reinforcement system, comprising a row of steel tube arch rings arranged parallel to the top surface of the arch ring along the direction of the bridge and arranged between the columns, the steel tube arch ring and the original main arch ring are wrapped together with a unidirectional carbon fiber cloth in an angle less than 10° with the radial direction of the arch bridge, and the bottom surface of the original main arch ring is provided with a unidirectional carbon fiber cloth laid along the length direction of the bridge; the steel tube arch ring is composed of multiple steel tube concrete sections arranged on the same axis and located on the top surface of the hollow section main arch ring between different columns; the roots of the two ends of the steel tube are connected by embedded steel bars preset on the adjacent structural components at both ends of the arch ring.

[0013] The preferred technical solution is a construction method of a carbon fiber constrained steel tube concrete arch ring reinforcement system, comprising the following steps:

[0014] Step 1: Install guardrails on the top surface of the arch ring, clean the top surface of the arch ring, and repair existing defects to ensure flatness;

[0015] Step 2: Install the construction hanging basket on the bottom surface of the arch ring, clean the bottom surface of the arch ring, and repair existing defects to ensure flatness;

[0016] Step 3: Attach carbon fiber cloth to the bottom surface of the arch ring. The carbon fiber cloth is unidirectional, and the fiber attachment direction is the same as the length of the bridge. Increase the number of carbon fiber cloth attachment layers in the column support area, the mid-span area where the arch ring and the main beam merge, and the arch foot area.

[0017] Step 4: Construction of steel pipe arch ring;

[0018] S1: First, lay the first steel pipe arch ring along the center line of the arch ring top surface. The specific steps are as follows:

[0019] a. Implant anchor steel bars at the base of the bridge's vertical members where both ends of the first steel tube arch ring touch, and maintain sufficient anchor length and number of steel bars;

[0020] b. Place the prefabricated steel pipe segments of the first steel pipe arch ring into the corresponding positions and connect them with the reserved steel bars;

[0021] c. At the same time, the first steel arch ring involves each segment of the prefabricated steel pipe through the casting hole involved therein to pour concrete inside it;

[0022] d. Stop grouting when grouting continues to occur in the pouring holes on the prefabricated steel pipes. During the grouting process, pay attention to cooling the concrete and vibrating it;

[0023] e When the concrete inside the first steel arch reaches the initial strength, the upper casting hole is closed and the installation of the two adjacent steel arches begins, specifically repeating steps a to e;

[0024] S2. After the construction of all steel pipe arch rings is completed, they are circumferentially wound through the hollow space between two adjacent columns. Continuous unidirectional fiber cloth is used for winding. At the same time, the winding angle is less than ±10° from the radial direction of the bridge, and the number of winding layers is not less than two.

[0025] A preferred technical solution is that the steel tube concrete arch ring is composed of multiple hollow steel tube arch segments placed in the hollow sections between adjacent columns, wherein the multiple hollow steel tube arch segments with the same axial plane constitute a complete steel tube concrete arch ring, and the first steel tube arch ring whose axial plane is located on the midline of the length direction of the arch ring top surface is called the first steel tube arch ring.

[0026] According to a preferred technical solution, the prefabricated steel pipe has a length equal to that of the hollow section, is arched in the vertical direction, and has a curvature that is the same as that of the top surface of the arch ring.

[0027] According to a preferred technical solution, the prefabricated steel pipe is provided with a row of casting holes arranged along the center line of the top surface of the prefabricated steel pipe and evenly spaced along the length direction for casting.

[0028] According to a preferred technical solution, end plates for fixing anchor steel bars are provided inside both ends of the prefabricated steel pipe.

[0029] In a preferred technical solution, the carbon fiber is a fiber-reinforced resin-based composite material containing carbon fiber.

[0030] According to a preferred technical solution, elastic sealing rings are provided at the contact surfaces between the two ends of the prefabricated steel pipe and the existing structural components.

[0031] According to a preferred technical solution, the lower inner surface of the prefabricated steel pipe is provided with a plurality of longitudinal ribs along its length.

[0032] The preferred technical solution is that the concrete pouring method inside the steel tube concrete arch ring is to pour only multiple hollow steel tubes that form a complete steel tube concrete arch ring each time, and multiple tubes are poured simultaneously; then, when the previously poured steel tube concrete arch ring reaches the structural strength, the next steel tube concrete arch ring is poured, and so on.

[0033] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0034] 1. The following four construction measures reduce the construction risk of the arch back section enlargement method and ensure the structural safety of this construction method;

[0035] a. Before construction on the arch surface, a simple carbon fiber reinforcement method is used to enhance the bending bearing capacity of the weak surface, which can effectively reduce the impact of construction loads on the weak section;

[0036] b. When adding new structures to the arch, the arch is divided into several longitudinal sections along its length, and construction loads are applied section by section. This avoids structural safety hazards caused by applying concentrated construction loads only at the arch base or in a certain area in the span. After the newly added structure in one longitudinal section has a certain bearing capacity, construction of the next longitudinal section can be carried out. This achieves the effect of gradually adjusting the arch pressure line along the longitudinal direction of the arch while reducing the construction load, thereby achieving the ultimate goal of restoring or improving the arch bearing capacity.

[0037] c. The ribbed hollow steel tube arch sections were first laid on the arch ring before pouring concrete. This reduced the construction load on the arch at one time. The connection between the two ends of the ribbed hollow steel tube arch sections and the existing structure provided temporary support for the arch. This partially restored the bearing capacity of the arch ring and provided a certain bearing capacity reserve for the next step of pouring concrete inside.

[0038] d. After the steel tube concrete is constructed on the arch, the carbon fiber method is used to transversely wrap the steel tube concrete and the original arch ring. This improves the transverse connection between the longitudinal sections through the restraint effect, while also improving the bending resistance of the new and old structures, thereby achieving the ultimate goal of restoring or increasing the pressure line of the arch ring;

[0039] 2. The ribbed hollow steel tube arch section used also plays the role of eliminating the need for construction formwork. Taking advantage of the favorable construction conditions above the arch, it further reduces the difficulty of construction organization;

[0040] 3. By sticking carbon fiber to the weak section of the bottom surface of the arch ring to improve the local bending bearing capacity and wrapping carbon fiber cloth with transverse constraints, the good durability unique to the carbon fiber reinforcement method is utilized to achieve durable reinforcement of the arch ring;

[0041] 4. The good shape-adaptability of carbon fiber reinforcement technology is utilized to achieve the property of not destroying the characteristic parts of the arch ring. It is suitable for the reinforcement of arch bridges with ribs at the arch bottom, making this construction method have a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The advantages of the above and / or additional aspects of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0043] Figure 1 It is a schematic diagram of the effect of the reinforcement system of the present invention.

[0044] Figure 2 This is a rendering of the first steel pipe being installed on the top surface of the arch ring of the present invention.

[0045] Figure 3 This is a schematic diagram of the effect of the vault of the present invention after all steel pipes are laid.

[0046] Figure 4 It is a schematic diagram of the effect of the arch ring of the present invention completing the fiber winding layer.

[0047] Figure 5 It is a schematic diagram of a steel pipe of the present invention.

[0048] Figure 6 It is a schematic cross-sectional view of a steel pipe according to the present invention.

[0049] Figure 7 It is a schematic diagram of the elastic sealing ring of the present invention.

[0050] in Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7The corresponding relationship between the figure marks and the component names is as follows.

[0051] Figure numerals: 1. main arch ring, 2. column, 3. carbon fiber cloth, 4. steel pipe, 5. concrete, 6. fiber winding layer, 7. steel bar, 41. longitudinal rib, 42. circumferential rib, 43. casting hole, 421. steel bar hole, 422. elastic sealing ring. Specific implementation plan

[0052] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features therein can be combined with each other without conflict.

[0053] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 As shown, the present invention provides a carbon fiber constrained steel tube concrete reinforced hollow arch bridge main arch ring, including a row of steel tube arch rings 4 arranged parallel to the top surface of the main arch ring 1 along the bridge direction and arranged between the columns 2, the steel tube arch rings 4 and the original main arch ring 1 are wrapped together with a unidirectional carbon fiber winding layer 6 in an angle less than 10° with the radial direction of the arch bridge, and a unidirectional carbon fiber layer 3 laid along the length direction of the bridge on the bottom surface of the original main arch ring 1; the steel tube arch ring 4 is composed of multiple steel tube 4 concrete 5 sections arranged on the same axis and located on the top surface of the hollow section main arch ring 1 between different columns 2; the roots of the two ends of the steel tube 1 are connected by embedded steel bars 7 preset on the adjacent structural components at both ends of the arch ring.

[0054] In this embodiment, the construction method of reinforcing the main arch ring of a hollow arch bridge with carbon fiber-constrained steel tube concrete includes the following steps:

[0055] Step 1: Install a guardrail on the top surface of the main arch ring 1, clean the top surface, and repair existing defects to ensure flatness;

[0056] Step 2: Install a construction hanging basket on the bottom surface of the main arch ring 1, clean the bottom surface of the arch ring, and repair existing defects to ensure flatness;

[0057] Step 3: Paste carbon fiber cloth 3 on the bottom surface of the main arch ring 1. The carbon fiber cloth 3 is unidirectional, and the fiber pasting direction is the same as the length direction of the bridge. In addition, increase the number of pasting layers of carbon fiber cloth 3 in the support area of ​​the column 2, the mid-span area where the main arch ring 1 and the main beam merge, and the arch foot area;

[0058] Step 4: Construction of 4 steel pipe arch rings;

[0059] S1, first, lay the first steel pipe 4 arch ring along the length center line of the top surface of the main arch ring 1, the specific steps are as follows:

[0060] a. In the first arch ring of the bridge at both ends of the contact vertical member 4 circumferential ribs 41 reserved for the root, the anchor steel 7 is implanted, and retain sufficient anchor length and number of steel bars;

[0061] b. Place the prefabricated steel pipe segments of the first steel pipe arch ring into the corresponding positions and connect them with the reserved steel bars;

[0062] c. At the same time, the first steel tube 4 involves each segmented prefabricated steel tube 4 through the casting holes 43 involved thereon and pouring concrete 5 inside thereof;

[0063] d. When the casting hole 43 is provided on the prefabricated steel pipe, the grouting is stopped after continuous grouting. During the grouting process, pay attention to the cooling and vibration of the concrete 5;

[0064] e When the first steel pipe 4 arches of concrete 5 reaches the initial strength, the closed casting hole 43, and began to install the two adjacent left and right steel pipes 4 arches, specifically repeat steps a to e;

[0065] S2. After completing the construction of all the steel pipe 4 arch rings, they are circumferentially wound through the hollow space between two adjacent columns 2. Continuous unidirectional fiber cloth is used for winding. At the same time, the winding angle is less than ±10° from the radial direction of the bridge, and the number of winding layers is not less than two.

[0066] In this embodiment, the steel pipe 4 concrete 5 arch ring is composed of multiple hollow steel pipe 4 arch segments placed in the hollow sections between adjacent columns, wherein multiple hollow steel pipe 4 arch segments with the same axial plane constitute a complete steel pipe 4 concrete 5 arch ring, wherein the first steel pipe 4 arch ring whose axial plane is located on the midline of the length direction of the top surface of the arch ring is called the first steel pipe 4 arch ring.

[0067] In this embodiment, the prefabricated steel pipe 4 has a length equal to the length of the hollow section, is arched in the vertical direction, and has the same curvature as the top surface curvature of the main arch ring 1 .

[0068] In this embodiment, the prefabricated steel pipe 4 is provided with a row of pouring holes 43 for pouring, which are arranged along the center line of the top surface of the prefabricated steel pipe 4 and are evenly spaced along the length direction.

[0069] In this embodiment, annular ribs 42 for fixing and anchoring the steel bars 7 are provided inside the two ends of the prefabricated steel pipe 4 , and the annular ribs are provided with steel bar holes 421 for connecting the steel bars 7 .

[0070] In this embodiment, the carbon fiber layer 3 is a fiber-reinforced resin-based composite material containing carbon fibers.

[0071] In this embodiment, elastic sealing rings 422 are provided at the contact surfaces between the two ends of the prefabricated steel pipe 4 and the existing structural components.

[0072] In this embodiment, the lower inner surface of the prefabricated steel pipe 4 is provided with a plurality of longitudinal ribs 41 along its length direction.

[0073] In this embodiment, the method of pouring concrete 5 in the steel pipe 4 concrete 5 arch ring is to pour only multiple hollow steel pipes 4 that form a complete row of steel pipe 4 concrete 5 arch rings each time, and multiple pipes are poured at the same time; then, when the previous poured steel pipe 4 concrete 5 arch ring reaches the structural strength, the next row of steel pipe 4 concrete 5 arch rings is poured, and so on.

[0074] The above is only a specific implementation method of the present invention, but the scope of protection of this patent is not limited to this. Any modification or replacement made by any technician familiar with this technical field within the technical solution or inventive concept of this patent should fall within the scope of protection of this patent.

Claims

1. A carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge, characterized by: It includes a row of steel tube arch rings arranged parallel to the top surface of the main arch ring along the direction of the bridge and set between the columns, a unidirectional carbon fiber winding layer that wraps the steel tube arch ring and the original main arch ring at an angle less than 10° to the radial direction of the arch bridge, and a unidirectional carbon fiber layer laid along the length direction of the bridge on the bottom surface of the original main arch ring; the steel tube arch ring is composed of multiple steel tube concrete sections arranged on the same axis and located on the top surface of the hollow section main arch ring between different columns; the roots of the two ends of the steel tube are connected by embedded steel bars preset on the adjacent structural components at both ends of the arch ring.

2. The carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge according to claim 1, characterized in that: The steel tube concrete arch ring is composed of multiple hollow steel tube arch segments placed in the hollow sections between adjacent columns. Multiple hollow steel tube arch segments with the same axial plane constitute a complete steel tube concrete arch ring. The first steel tube arch ring with the axial plane located on the midline of the length direction of the arch ring top surface is called the first steel tube arch ring.

3. The carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge according to claim 1, characterized in that: The prefabricated steel pipe has a length equal to that of the hollow section, is arched in the vertical direction, and has the same curvature as the top surface of the main arch ring.

4. The carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge according to claim 1, characterized in that: The prefabricated steel pipe is provided with a row of pouring holes for pouring, which are arranged along the center line of the top surface of the prefabricated steel pipe and are evenly spaced along the length direction.

5. The carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge according to claim 1, characterized in that: Circumferential ribs for fixing anchoring steel bars are provided inside the two ends of the prefabricated steel pipe, and the circumferential ribs are provided with steel bar holes for connecting steel bars.

6. The carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge according to claim 1, characterized in that: The carbon fiber is a fiber-reinforced resin-based composite material containing carbon fiber.

7. The carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge according to claim 1, characterized in that: Elastic sealing rings are provided at the contact surfaces between the two ends of the prefabricated steel pipe and the existing structural components.

8. The carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge according to claim 1, characterized in that: The inner surface of the lower side of the prefabricated steel pipe is provided with a plurality of longitudinal ribs along the length direction thereof.

9. The carbon fiber-constrained steel tube concrete reinforced main arch ring of a hollow arch bridge according to claim 1, characterized in that: The concrete pouring method of the steel tube concrete arch ring is to pour only multiple hollow steel tubes that form a complete row of steel tube concrete arch rings each time, and multiple tubes are poured simultaneously; then when the steel tube concrete arch rings of the previous row reach the structural strength, the next row of tube concrete arch rings is poured, and so on.

10. A construction method for reinforcing the main arch ring of a hollow arch bridge using carbon fiber-confined steel tube concrete as claimed in any one of claims 1 to 9, characterized in that: The following steps are included: Step 1: Install guardrails on the top surface of the main arch, clean the top surface, and repair existing defects to ensure flatness; Step 2: Install the construction hanging basket on the bottom surface of the main arch ring, clean the bottom surface of the arch ring, and repair existing defects to ensure flatness; Step 3: Attach carbon fiber cloth to the bottom surface of the main arch ring. The carbon fiber cloth is unidirectional, and the fiber attachment direction is the same as the length of the bridge. Increase the number of carbon fiber cloth attachment layers in the column support area, the mid-span area where the main arch ring and the main beam merge, and the arch foot area. Step 4: Construction of steel pipe arch ring; S1. First, lay the first steel pipe arch ring along the center line of the main arch ring's top surface in the longitudinal direction. The specific steps are as follows: a. Anchor steel bars are embedded in the reserved annular ribs at the base of the vertical bridge members where the two ends of the first steel tube arch ring touch each other, and sufficient anchorage length and number of steel bars are reserved; b. Place the prefabricated steel pipe segments of the first steel pipe arch ring into the corresponding positions and connect them with the reserved steel bars; c. At the same time, the first steel arch ring involves each segment of the prefabricated steel pipe through the casting hole involved therein and pouring concrete inside it; d. Stop grouting when grouting continues to occur in the pouring holes on the prefabricated steel pipes. During the grouting process, pay attention to cooling the concrete and vibrating it; e When the concrete inside the first steel arch reaches the initial strength, the upper casting hole is closed and the installation of the two adjacent steel arches begins, specifically repeating steps a to e; S2. After the construction of all steel pipe arch rings is completed, they are circumferentially wound through the hollow space between two adjacent columns. Continuous unidirectional fiber cloth is used for winding. At the same time, the winding angle is less than ±10° from the radial direction of the bridge, and the number of winding layers is not less than two.

Images