Fish ridge type thin-wall continuous rigid frame aqueduct structure and design method thereof

Abstract

The invention discloses a fish ridge type thin-wall continuous rigid frame aqueduct structure and a design method thereof, and relates to the technical field of water conservancy projects, and the fish ridge type thin-wall continuous rigid frame aqueduct structure comprises an upper water delivery bearing structure and pier columns; the upper water delivery bearing structure comprises a water delivery section and a variable-height reinforcing section, and the pier column is used for supporting the water delivery section; a height-variable reinforcing section extending upwards is arranged at the position, right opposite to the top of the pier column, of the water conveying section. The variable-height reinforcing sections are symmetrically arranged along the center line in the height direction of the pier column; according to the scheme, the neutral axis is actively regulated and controlled to move upwards through the height-variable reinforcing section, and a stress distribution mode with the pressure bearing of the water-passing section as the main part and the tension bearing of the height-variable reinforcing section as the main part is formed; and the whole aqueduct structure is safer and more durable while the spanning capability is kept.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water conservancy engineering, in particular to a fish-ridge thin-walled continuous rigid structure aqueduct and a design method thereof. BACKGROUND

[0002] In recent years, China's water conservancy construction has entered a boom, and is accelerating the construction of the national water network. Aqueducts are the most widely used crossing structures in water diversion projects. However, in mountainous areas, the construction of aqueducts often encounters high overhead, crossing wide and gentle valleys, highways, railways, navigable rivers, etc. The crossing capacity of simply supported beam aqueducts with a maximum span of about 40m is limited, and there is an urgent need for new aqueduct structure systems and supporting design methods that can greatly improve the crossing capacity.

[0003] Prestressed concrete continuous rigid frame bridges are one of the commonly used bridge types in the field of highways and railways. Due to the mechanical characteristics of continuous beam, consolidation of piers, beams, and foundations, etc., the crossing capacity is extremely strong, and the hanging basket construction can be used to reduce the impact on the lower part. The Caodi Slope, Xujiawan, Hegoutou, Jiaojia Aqueducts of the First Phase Project of Guizhou Central Water Conservancy Hub and the Hongshuihe Aqueduct of the Water Diversion and Irrigation Area Project of the Le'an Reservoir of the Guizhong Water Control in Guangxi refer to the size of the prestressed continuous rigid frame bridge of the highway and propose a variable box and variable cross-section prestressed continuous rigid frame aqueduct type, which increases the main span of the aqueduct structure below 25m 3 to more than 100m.

[0004] Although the variable box and variable cross-section prestressed continuous rigid frame aqueducts in the above projects have improved the crossing capacity, they basically use the highway and railway industry standards, and the water passage section is located above the load-bearing structure, resulting in the water passage section being located in the negative bending moment zone, as shown in Figure 1 Once the prestress fails or partially fails, combined with the creep of concrete, the main beam is at high risk of cracking and leakage, and the design of variable cross-section also brings certain difficulties to design and construction. Therefore, it is a problem to be solved in the field to propose a new aqueduct structure and design method that can achieve or even improve the crossing capacity of the current technical solution and make the structure safer and more durable. SUMMARY

[0005] To solve the problems of the prior art, the purpose is to provide a fish-ridge thin-walled continuous rigid structure aqueduct and a design method thereof. By using the present application, the neutral axis is actively controlled to move up by changing the height of the reinforcement section, forming a stress distribution pattern in which the water passage section is mainly in compression and the variable height reinforcement section is mainly in tension. The crossing capacity is retained while making the entire aqueduct structure safer and more durable.

[0006] The present application is implemented by the following technical solutions:

[0007] A fish-ridge thin-walled continuous rigid structure aqueduct, comprising:

[0008] Upper water conveyance load-bearing structure and piers;

[0009] The upper water conveyance load-bearing structure includes a water conveyance section and a variable height reinforcement section, and the pier is used to support the water conveyance section; a variable height reinforcement section extending upward is provided at the position of the water conveyance section directly opposite the top of the pier; the variable height reinforcement section is symmetrically arranged along the center line of the height direction of the pier.

[0010] The neutral axis of the upper water conveyance load-bearing structure in the variable height reinforced section area is located above the water passage section.

[0011] Compared to existing technologies where the water-passing section is located above the load-bearing structure, resulting in the water-passing section being in the negative bending moment zone, and the risk of main beam cracking and leakage is huge once the prestress fails, this invention provides a fishback-shaped thin-walled continuous rigid frame aqueduct structure and its design method. By actively adjusting the neutral axis upward through the variable height reinforcement section, a stress distribution mode is formed in which the water-passing section is mainly under compression and the variable height reinforcement section is mainly under tension. This makes the entire aqueduct structure safer and more durable while retaining its crossing capacity. The specific plan includes, from top to bottom, an upper water conveyance load-bearing structure, piers, and a foundation structure. The upper water conveyance load-bearing structure includes the water conveyance section. Based on the stress characteristics of the aqueduct structure during construction and operation, a variable-height reinforced section needs to be added above the water conveyance section. The variable-height reinforced section is mainly set at the location of the corresponding pier, realizing the vertical distribution of the variable-height reinforced section and the pier. In this way, by actively adjusting the centroid of the cross section of the variable-height reinforced section, the neutral axis can be moved upward, so that the neutral axis is located above the water passage section. Thus, a stress distribution pattern can be formed in which the water passage section is mainly under compression and the variable-height reinforced section is mainly under tension. Specifically, the variable-height reinforced section adopts a longitudinally gradually changing cross-section design, similar to a fishbone shape. Its height variation function is positively correlated with the aqueduct's bending moment envelope, achieving spatial matching between the structure's bending stiffness and bending moment requirements. This, combined with the prestressed system, reduces the maximum tensile stress in the water-crossing section to within the design specifications' allowable range, making the aqueduct less prone to cracking. While maintaining its spanning capacity, this makes the entire aqueduct structure safer and more durable. Furthermore, pier structures with appropriate stiffness can be selected based on the aqueduct's span and height. The longitudinal stiffness of the piers should be minimized while meeting the stability requirements during aqueduct construction and operation to accommodate horizontal displacement caused by temperature changes, concrete shrinkage, and creep. The lateral stiffness of the piers should be appropriately large to accommodate torsion and displacement caused by lateral unbalanced loads, wind loads, or seismic loads. In terms of structural shape, double-column thin-walled piers or double-column solid piers, single-column thin-walled piers or single-column solid piers, as well as V-shaped or Y-shaped piers, can be selected. The basic structure includes shallow foundations such as slab foundations and deep foundations such as pile foundations and caissons.

[0012] Furthermore, the highest point of the variable-height reinforced section is located on the centerline of the pier's height direction, and the two sides of the highest point are connected to the water conveyance section by straight lines, arcs, or gentle curves. Preferably, the connection method is an arc.

[0013] Furthermore, the highest point of the variable-height reinforced section is transitioned via a curve. The curve transition can be either an arc or a hyperbola, among other options.

[0014] Furthermore, the variable height reinforced section is further optimized by providing several prestressed steel strands. These prestressed steel strands are distributed sequentially along the height direction of the variable height reinforced section, and are arranged along the length direction of the top surface of the variable height reinforced section.

[0015] Furthermore, the variable height reinforced section and the water conveyance section are integrally formed.

[0016] Furthermore, the water conveyance section is further optimized by having several piers supporting it along its length, and a variable-height reinforcement section is provided at each of the piers.

[0017] Furthermore, the upper water conveyance load-bearing structure is a continuous concrete or prestressed concrete aqueduct with a single-box single-chamber or double-box double-chamber structure of equal cross-section.

[0018] Furthermore, the cross-section of the upper water conveyance load-bearing structure is rectangular, U-shaped, circular, or trapezoidal.

[0019] Furthermore, the top surface of the upper water conveyance load-bearing structure is made of weathering steel, stainless steel plate and other materials to form a composite structure with the aqueduct concrete.

[0020] Further optimization can be achieved by incorporating landscape design into the upper water conveyance load-bearing structure and pier foundation structure based on the actual site conditions, thus realizing a good engineering landscape effect.

[0021] Further solutions:

[0022] This invention also provides a design method for a fishback-shaped thin-walled continuous rigid frame aqueduct structure, comprising the following steps:

[0023] S1: Determine the span scheme of the fish-ridge continuous rigid frame aqueduct structure based on external conditions; the span scheme includes determining the maximum span of the piers and the fish-ridge continuous rigid frame aqueduct structure. and minimum span ;

[0024] S2: Determine the dimensional parameters and cross-sectional shape of the upper water conveyance load-bearing structure based on hydraulics and engineering experience;

[0025] S3: Subsequently, the fishback spine size optimization model was used to determine the ideal state that conforms to engineering requirements. , , and hy; where hy is the center height of the variable height reinforcement section; and These are the lengths from the center of the variable-height reinforced section to both ends; The distance from one end of the variable height reinforced section to the end of the water conveyance section on one side; The distance from the other end of the variable height reinforced section to the end of the water conveyance section on the other side;

[0026] S4: Based on the preliminary scheme determined in steps S1-S3, determine the alignment of the variable height reinforced section, the arrangement of prestressed steel strands, the construction sequence, and the type of temporary support.

[0027] S5: Subsequently, a three-dimensional finite element model of the fishback-shaped continuous rigid frame aqueduct structure was established for structural simulation. Through stress control, the model was continuously optimized and adjusted. , , , And hy value, until the stress and deformation meet the requirements of the concrete design code, determine the parameters of the upper water conveyance load-bearing structure;

[0028] S6: Finally, based on engineering experience and relevant specifications, complete the detailed structural design of the aqueduct and the design of its substructure.

[0029] Further optimization is achieved in step S4, based on the load balance method and The distribution pattern has been preliminarily determined to determine the arrangement scheme of the prestressed steel strands, among which, The bending moment is due to its own weight. For water load bending moment, This is the bending moment caused by the combined action of its own weight and water load.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] This invention provides a fishback-shaped thin-walled continuous rigid frame aqueduct structure and its design method. By adopting this scheme, the neutral axis is actively adjusted upward by the variable height reinforcement section, forming a stress distribution mode in which the water passage section is mainly under pressure and the variable height reinforcement section is mainly under tension. This makes the entire aqueduct structure safer and more durable while retaining the crossing capacity. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0033] Figure 1 This is a schematic diagram of an aqueduct design in the prior art;

[0034] Figure 2 A schematic diagram of the fishbone-shaped continuous rigid frame aqueduct structure provided by the present invention;

[0035] Figure 3 A perspective view of the fishbone-shaped continuous rigid frame aqueduct structure provided by the present invention;

[0036] Figure 4 The normal stress distribution diagram of the support section of the fishback-shaped continuous rigid frame aqueduct structure provided by the present invention;

[0037] Figure 5 Schematic diagrams of various cross-sectional designs of the fishbone-shaped continuous rigid frame aqueduct structure provided by the present invention.

[0038] Figure 6 This is a diagram showing the distribution of prestressed steel strands in the fishback-shaped continuous rigid frame aqueduct structure provided by the present invention.

[0039] Figure 7 This is a working condition design diagram of the fishbone-shaped continuous rigid frame aqueduct structure under automatic loading provided by the present invention.

[0040] Figure 8 This is a working condition design diagram of the fishbone-shaped continuous rigid frame aqueduct structure under water load provided by the present invention.

[0041] Figure 9 The rotational stiffness calculation and design diagram of the fishbone-shaped continuous rigid frame aqueduct structure provided by the present invention;

[0042] Figure 10 The cross-sectional dimension diagram of the upper water conveyance load-bearing structure provided for this invention;

[0043] Figure 11 A schematic diagram of the normal stress distribution of the fishbone-shaped continuous rigid frame aqueduct structure provided by the present invention;

[0044] Figure 12 This is a schematic diagram of the normal stress distribution in the cross section of the fishback-shaped continuous rigid frame aqueduct structure provided by the present invention.

[0045] The attached diagram shows the markings and corresponding component names:

[0046] 1-Upper water conveyance load-bearing structure, 101-Variable height reinforced section, 102-Prestressed steel strands, 103-Water conveyance section, 2-Pier column. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0048] Example 1: This Example 1 provides a fishback-shaped thin-walled continuous rigid frame aqueduct structure, such as... Figures 2-6 As shown, it includes:

[0049] Upper water conveyance load-bearing structure 1 and pier 2;

[0050] The upper water conveyance load-bearing structure 1 includes a water conveyance section 103 and a variable height reinforcing section 101. The pier 2 is used to support the water conveyance section 103. A variable height reinforcing section 101 extending upward is provided at the position of the water conveyance section 103 directly opposite the top of the pier 2. The variable height reinforcing section 101 is symmetrically arranged along the center line of the height direction of the pier 2.

[0051] The neutral axis of the upper water conveyance load-bearing structure 1 in the variable height reinforced section 101 area is located above the water passage section.

[0052] Compared to existing technologies where the water-passing section is located above the load-bearing structure, resulting in the water-passing section being in the negative bending moment zone, and the risk of main beam cracking and leakage is huge once the prestress fails, this invention provides a fishback-shaped thin-walled continuous rigid frame aqueduct structure and its design method. By actively adjusting the neutral axis upward through the variable height strengthening section 101, a stress distribution mode is formed in which the water-passing section is mainly under compression and the variable height strengthening section 101 is mainly under tension. This makes the entire aqueduct structure safer and more durable while retaining the crossing capacity. In the specific scheme, from top to bottom, it includes the upper water conveyance load-bearing structure 1, the pier 2, and the foundation structure. The upper water conveyance load-bearing structure 1 includes the water conveyance section 103. Based on the stress characteristics of the aqueduct structure during construction and operation, a variable height reinforcement section 101 needs to be added on the upper side of the water conveyance section 103. The variable height reinforcement section 101 is mainly set at the position of the corresponding pier 2, so that the variable height reinforcement section 101 and the pier 2 are distributed vertically. In this way, by actively adjusting the centroid of the cross section of the variable height reinforcement section 101, the neutral axis can be moved upward, so that the neutral axis is located above the water passage section. In this way, a stress distribution mode in which the water passage section is mainly under compression and the variable height reinforcement section 101 is mainly under tension can be formed. Specifically, the variable-height reinforced section 101 adopts a longitudinally gradually changing cross-section design, similar to a fishbone shape. Its height variation function is positively correlated with the bending moment envelope of the aqueduct, achieving spatial matching between the structural bending stiffness and bending moment requirements. This, under the synergistic effect of the prestressed system, reduces the maximum tensile stress in the water-crossing section to within the allowable range of the design specifications, making the aqueduct less prone to cracking. While maintaining its spanning capacity, this makes the entire aqueduct structure safer and more durable. Furthermore, pier 2 structures with appropriate stiffness can be selected based on the aqueduct's span and height. The longitudinal stiffness of pier 2 should be minimized while meeting the stability requirements of the aqueduct during construction and operation to accommodate horizontal displacement caused by temperature changes, concrete shrinkage, creep, and other factors. The lateral stiffness of pier 2 should be appropriately large to accommodate the torsion and displacement of the aqueduct under lateral unbalanced loads, wind loads, seismic loads, etc. In terms of structural shape, double-column thin-walled piers or double-column solid piers, single-column thin-walled piers or single-column solid piers, or V-shaped or Y-shaped piers can be selected. The basic structure includes shallow foundations such as slab foundations and deep foundations such as pile foundations and caissons.

[0053] In this embodiment, the highest point of the variable-height reinforcing section 101 is located on the center line of the pier column 2 in the height direction. The two sides of the highest point are connected to the water conveyance section 103 by straight lines, arcs, or gentle curves. Among them, the arc connection method is preferred.

[0054] In this embodiment, the highest point of the variable height reinforcing section 101 is transitioned by a curve. The curve transition can be either an arc or a hyperbola, etc.

[0055] In this embodiment, as Figure 6As shown, a plurality of prestressed steel strands 102 are also provided in the variable height strengthening section 101. The plurality of prestressed steel strands 102 are distributed sequentially in the height direction of the variable height strengthening section 101, and the prestressed steel strands 102 are arranged along the length direction of the top surface of the variable height strengthening section 101.

[0056] In this embodiment, the variable height reinforcing section 101 and the water conveying section 103 are integrally formed.

[0057] In this embodiment, a number of piers 2 are sequentially supported along the length of the water conveyance section 103, and a variable height reinforcing section 101 is provided at each of the piers 2 in the water conveyance section 103.

[0058] In this embodiment, as Figure 5 As shown, the upper water conveyance load-bearing structure 1 is a continuous concrete or prestressed concrete aqueduct with a single-box single-chamber or double-box double-chamber structure of equal cross-section.

[0059] In this embodiment, as Figure 5 As shown, the water-carrying cross-section of the upper water-carrying load-bearing structure 1 is rectangular, U-shaped, circular, or trapezoidal.

[0060] Example 2: This Example 2 is a further optimization based on Example 1, such as... Figures 2-12 As shown, a design method for a fishback-shaped thin-walled continuous rigid frame aqueduct structure is provided, including the following specific steps:

[0061] 1. Preliminary determination of the span of the fishback-shaped continuous rigid frame aqueduct. First, collect information on external conditions below the aqueduct that affect the layout of the supporting structure, such as railways, highways, buildings, and waterways. Then, select the pier locations of the supporting structure and determine the maximum span based on these constraints. and minimum span The span scheme of the aqueduct has been preliminarily determined. The spans should be symmetrically arranged, and the space of the buildings below should not be encroached on unless necessary, in order to save on land acquisition and demolition costs and highlight the advantages of hanging basket construction.

[0062] 2. Determine the internal dimensions of the aqueduct based on hydraulic calculations, and preliminarily determine the dimensions of the aqueduct's concrete structure based on engineering experience. The wall thickness can be generally taken as 35~100cm, such as... Figure 5 As shown, the cross-sectional shape can be U-shaped, circular, egg-shaped, rectangular, etc., and multiple slots can also be arranged.

[0063] 3. Based on the proposed fishback spine size optimization model, select and determine models that conform to engineering requirements. , , , hy. Among them, such as Figure 7As shown, a unit is defined by a pier 2 and the water conveyance section 103 above it. The two ends of the water conveyance section 103 at this location are taken as the midpoint between the pier 2 and the adjacent pier 2; hy is the center height of the variable height reinforcement section 101. and These are the lengths from the center of the variable-height reinforced section 101 to both ends; The distance from one end of the variable height reinforced section 101 to the end of the side water conveyance section 103; The distance from one end of the variable height reinforced section 101 to the end of the other side water conveyance section 103 is given; thus, the parameter design of several units can be quickly calculated.

[0064] 4. Draw the preliminary structure of the fishback continuous rigid frame aqueduct according to the above layout parameters. The main beams of the fishback structure are connected by straight lines, arcs or gentle curves, with arcs being the preferred method. The top can be transitioned by arcs or hyperbolas or other curves according to the shape requirements.

[0065] 6. According to the load balance method and The distribution pattern has been preliminarily determined, and the arrangement scheme of prestressed steel strand 102 has been determined. The bending moment is due to its own weight. For water load bending moment, This is the bending moment caused by the combined action of its own weight and water load.

[0066] 7. Based on a preliminary construction plan with a segment length of 3-5m, determine the construction sequence and temporary support methods.

[0067] 8. Establish a three-dimensional finite element model to conduct structural simulation. Stress control principles: For aqueducts of grades 1-3, the inner surface should be controlled according to the strict requirement of no cracks appearing, and the outer surface should be controlled according to the general requirement of no cracks appearing; for aqueducts of grades 4-5, the components should be controlled according to the general requirement of no cracks appearing.

[0068] 9. Continuously optimize and adjust the aqueduct based on the simulation structure. , , , The stress and hy values ​​are determined until the stress and deformation meet the requirements of the concrete design specifications, thus determining the upper structure of the aqueduct.

[0069] 10. Finally, based on engineering experience and relevant specifications, complete the detailed structural design of the aqueduct and the design of its substructure.

[0070] In the above steps, the optimization model for the fish spine size in point three is as follows:

[0071] First, set the conditions. , , Subsequently, calculations were performed under the working condition of maximum double cantilever with only self-weight considered. , , , Each of their own weight bending moments , The total length of water conveyance section 103 is as follows: The maximum span value is designed for the mid-span. To design the minimum span at mid-span, For the material volume of the upper water conveyance load-bearing structure, The total width of the upper water conveyance load-bearing structure is 1. The height of water conveyance section 103 below the variable height reinforcement section 101, For the thickness of the side wing plate, The distance between the two winglets. The thickness of the bottom web. Maximum height of variable height reinforced section 101; such as Figure 7 As shown. Wherein:

[0072] ;

[0073] In the above formula, For self-weight load, L is the distance from one end of the water conveyance section 103 to any point on its own, and L is the total length of the water conveyance section 103. This represents the peak value of the triangular distributed load generated by the self-weight of the fish spine.

[0074] Subsequently, under the working condition of water flow and considering only the water load, calculations were performed respectively. , , , Each segment's individual water load bending moment ;like Figure 8 As shown. Wherein:

[0075] ;

[0076] In the above formula, μ BA M is the moment distribution factor for the side span, where M is the moment being distributed. For water load, μ BC This is the mid-span bending moment distribution coefficient.

[0077] The calculation of the bending moment mentioned above also includes the following steps:

[0078] 1. Figure 9 By applying a rigid arm constraint at point B to the middle structure, the basic system of the displacement method can be obtained. BA is a single-span beam fixed at one end and simply supported at the other end, BC is a single-span beam fixed at one end and oriented at the other end, and BD is a single-span beam fixed at both ends.

[0079] 2. Calculate the fixed-end moment: This is the bending moment at the end of the rod generated by the external load on the basic system of the displacement method, as shown in the formula below, with the lower part under tension being positive.

[0080] 3. Rotational stiffness calculation: e.g. , , . , , , For variable cross-section; where: For the stiffness of the side span members, For the stiffness of the mid-span member, For the stiffness of pier column 2, Let BA be the rotational stiffness of the rod. Let BC be the rotational stiffness. Let BD be the rotational stiffness of the rod. For calculated values, For calculated values, This is a calculated value.

[0081] 4. Distribution coefficient: μ BA = μ BC = μ BD = μ BA Let μ be the BA rod allocation coefficient. BC μ is the distribution coefficient for bar BC. BD The BD bar allocation coefficient.

[0082] 5. Distribution and transmission: Distribute the unbalanced bending moment to each member and transmit it to the far end.

[0083] 6. Final bending moment: The final bending moment at the end of the member can be obtained by adding the fixed-end bending moment to the distributed or transmitted bending moment according to the superposition principle.

[0084] Among them, fixed-end bending moment:

[0085] ;

[0086] Distributed torque: ;

[0087] Moment distribution process:

[0088] ;

[0089] in, Based on the above formula, the self-weight bending moment of each can be obtained. and water load bending moment Finally, according to the function and substitute Thus determining the optimal ;in Let be the support reaction force at point A.

[0090] In the above formula, the fixed-end moment refers to the moment at the end of the rod generated by the external load on the basic system when the rotating node is fixed and the displacement method is used. Let be the fixed-end moment at point A of member AB. Let B be the fixed-end moment of member BA at point B. Let B be the fixed-end moment of member BC. Let C be the fixed-end moment of member CB at point C. Let B be the fixed-end moment of member BD;

[0091] M is the unbalanced moment, which is the sum of the fixed-end moments of the rods connected to the rotating joint, and its value is equal to the rigid arm reaction moment. The value of the bending moment at point B in member BA after moment distribution. The value of the bending moment at point B in member BC after moment distribution. The value of the bending moment at point B in member BD after moment distribution. This represents the bending moment at point C of member CB after moment distribution. This represents the bending moment value at point D of member DB after moment distribution. The distribution process is shown in the table below:

[0092] Moment Distribution Process Table

[0093]

[0094] By adopting the above scheme, the neutral axis is moved upward by actively adjusting the variable height strengthening section 101, forming a stress distribution mode in which the water passage section is mainly under pressure and the variable height strengthening section 101 is mainly under tension. That is, by adjusting the variable height fish spine-shaped structure and prestressed steel strands located at the top of the aqueduct, it is relatively easy to maintain the compressive stress in the water passage section, so as to make the entire aqueduct structure safer and more durable while retaining the crossing capacity.

[0095] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fishback-shaped thin-walled continuous rigid frame aqueduct structure, characterized in that, include: Upper water conveyance load-bearing structure (1) and pier (2); The upper water conveyance load-bearing structure (1) includes a water conveyance section and a variable height reinforcement section (101). The pier (2) is used to support the water conveyance section. A variable height reinforcement section (101) extending upward is provided at the position of the water conveyance section directly opposite the top of the pier (2). The variable height reinforcement section (101) is symmetrically arranged along the center line of the height direction of the pier (2). The neutral axis of the upper water conveyance load-bearing structure (1) in the variable height reinforced section (101) area is located above the water flow section.

2. The fishback-shaped thin-walled continuous rigid frame aqueduct structure according to claim 1, characterized in that, The highest point of the variable height reinforced section (101) is located on the center line of the height direction of the pier (2), and the two sides of the highest point are connected to the water conveyance section by straight lines, arcs or gentle curves.

3. The fishback-shaped thin-walled continuous rigid frame aqueduct structure according to claim 1, characterized in that, The highest point of the variable height reinforced section (101) is transitioned by a curve.

4. The fishback-shaped thin-walled continuous rigid frame aqueduct structure according to claim 1, characterized in that, The variable height strengthening section (101) is further provided with a number of prestressed steel strands (102). The prestressed steel strands (102) are distributed sequentially in the height direction of the variable height strengthening section (101), and the prestressed steel strands (102) are arranged along the length direction of the top surface of the variable height strengthening section (101).

5. The fishback-shaped thin-walled continuous rigid frame aqueduct structure according to claim 1, characterized in that, The variable height reinforced section (101) and the water conveyance section are integrally formed.

6. The fishback-shaped thin-walled continuous rigid frame aqueduct structure according to claim 1, characterized in that, Several piers (2) are sequentially supported along the length of the water conveyance section, and a variable height reinforcement section (101) is provided at each of the piers (2) of the water conveyance section.

7. The fishback-shaped thin-walled continuous rigid frame aqueduct structure according to claim 1, characterized in that, The upper water conveyance load-bearing structure (1) is a continuous concrete or prestressed concrete aqueduct with a single-box single-chamber or double-box double-chamber structure of equal cross section.

8. The fishback-shaped thin-walled continuous rigid frame aqueduct structure according to claim 1, characterized in that, The water passage section of the upper water conveyance load-bearing structure (1) is rectangular, U-shaped, circular or trapezoidal.

9. A design method for a fishback-shaped thin-walled continuous rigid frame aqueduct structure according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Determine the span scheme of the fishback-shaped continuous rigid frame aqueduct structure based on external conditions; the span scheme includes determining the piers (2) and the maximum span of the fishback-shaped continuous rigid frame aqueduct structure. and minimum span ; S2: Determine the size parameters and cross-sectional shape of the upper water conveyance load-bearing structure (1) based on hydraulics and engineering experience; S3: Subsequently, the fishback spine size optimization model was used to determine the ideal state that conforms to engineering requirements. , , and hy; where hy is the center height of the variable height reinforcement section (101); and These are the lengths from the center of the variable height reinforced section (101) to both ends, respectively. The distance from one end of the variable height reinforced section (101) to the end of the water conveyance section on one side; The distance from the other end of the variable height reinforced section (101) to the end of the water conveyance section on the other side; S4: Based on the preliminary scheme determined in steps S1-S3, determine the alignment, prestressed steel strand arrangement, construction sequence and temporary support type of the variable height reinforced section (101); S5: Subsequently, a three-dimensional finite element model of the fishback-shaped continuous rigid frame aqueduct structure was established for structural simulation. Through stress control, the model was continuously optimized and adjusted. , , , And hy value, until the stress and deformation meet the requirements of the concrete design code, determine the parameters of the upper water conveyance load-bearing structure (1); S6: Finally, based on engineering experience and relevant specifications, complete the detailed structural design of the aqueduct and the design of its substructure.

10. The design method for a fishback-shaped thin-walled continuous rigid frame aqueduct structure according to claim 9, characterized in that, In step S4, according to the load balance method and The distribution pattern has been preliminarily determined to determine the arrangement scheme of the prestressed steel strands, among which, The bending moment is due to its own weight. For water load bending moment, This is the bending moment caused by the combined action of its own weight and water load.

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