Design method of continuous rigid frame aqueduct

Abstract

The invention relates to the technical field of water conservancy projects, in particular to a design method of a continuous rigid frame aqueduct. Comprising the following steps that the building position of the continuous rigid frame aqueduct is determined, and the aqueduct span arrangement of the continuous rigid frame aqueduct is drawn up according to the building position; hole span arrangement, side span and main span are determined according to a preset side-mid span ratio range of the continuous rigid frame aqueduct; the root beam height and the closure section beam height are determined according to the main span and the preset height-span ratio range of the continuous rigid frame aqueduct; the thickness range of a plate, the length of a pier top cast-in-place section, the length of a closure section and a groove body bottom curvilinear equation are determined, and a suspended casting section is segmented; the center distance of the double-limb thin-wall pier and the center distance of double limbs are determined; arranging prestressed steel beams for the continuous rigid frame aqueduct in the longitudinal direction and the transverse direction respectively; and constructing a finite element model and carrying out finite element analysis. According to the design theory and method of the continuous rigid frame aqueduct, rapid design of the continuous rigid frame aqueduct can be achieved, and a basis can be provided for standard compilation.

Description

Technical Field

[0001] This application relates to the field of water conservancy engineering technology, specifically to a design method for a continuous rigid frame aqueduct. Background Technology

[0002] Aqueducts are water conveyance structures that cross major intersections such as mountain valleys, river valleys, stream valleys, depressions, and roads. They have lower head loss than inverted siphons and are among the water conveyance structures with the lowest head loss along the course of water diversion projects. Constructing aqueducts in mountainous and canyon terrain often presents challenges such as high piers, large spans, and long channels, making conventional simply supported aqueducts and arch aqueducts unsuitable. Therefore, multi-span continuous rigid frame aqueducts are required. Continuous rigid frame aqueducts are a structural system of aqueducts with pier-beam connections, exhibiting the stress characteristics of continuous beams.

[0003] Continuous rigid frame aqueducts adopt prestressed concrete structures and feature an integrated bridge-channel structure, with water transported within the caisson. Continuous rigid frame aqueducts are a new type of hydraulic aqueduct structure that has seen rapid development in the past decade. However, a complete theoretical system for their design has not yet been summarized. The design usually requires continuous trial calculations to arrive at a reasonable structural form. Trial calculations are a tedious and inefficient process.

[0004] While existing technologies disclose the structural types or local special structural connection techniques of continuous rigid frame aqueducts, they do not summarize the general design methods for continuous rigid frame aqueducts, nor are there any completed standards or specifications to guide the design. This leaves the design process without a basis, and determining the structural type of continuous rigid frame aqueduct is the key and difficult point in the entire design process. Summary of the Invention

[0005] This application aims to solve at least one of the technical problems in the background art by providing a design method for continuous rigid frame aqueducts.

[0006] This application is achieved through the following technical solution: A design method for continuous rigid frame aqueducts includes the following: Determine the construction location of the continuous rigid frame aqueduct, and formulate the span arrangement of the continuous rigid frame aqueduct based on the construction location. The arrangement of spans, as well as the spans of the side spans and the main span, are determined based on the preset range of the side-to-mid span ratio of the continuous rigid frame aqueduct. The root beam height and closure section beam height are determined based on the main span and the pre-set range of the height-to-span ratio of the continuous rigid frame aqueduct. Determine the plate thickness range, the length of the cast-in-place section at the top of the pier, the length of the closure section, and the curve equation of the bottom of the trench, and then divide the cantilever section into segments. Determine the center-to-center distance of the two-limb thin-walled piers and the center-to-center distance of the two limbs; Prestressed steel strands are configured in both the longitudinal and transverse directions for continuous rigid frame aqueducts. Construct a finite element model and perform finite element analysis.

[0007] The design method for continuous rigid frame aqueducts provided in this application addresses the problems of low design efficiency and lack of general design methods and standard guidance in existing technologies. It systematically presents a series of detailed and operational design steps, from determining the construction location and span arrangement, to span arrangement, determining beam height, plate thickness, and segmentation, to configuring prestressed steel strands and constructing finite element model analysis. It provides a complete approach and methodology for the design of continuous rigid frame aqueducts, effectively improves design efficiency, solves the problem of lack of design basis, and helps to promote the standardization and normalization of continuous rigid frame aqueduct design.

[0008] In some alternative embodiments, the span ratio range of the edge is... ,in, For the side span, The main span.

[0009] In some optional embodiments, the height-to-span ratio range includes the range of the ratio of the root beam height to the main span. and the range of beam height of the closure section to the span of the main span ,in, For the height of the root beam, The closure section is of high beam height.

[0010] In some optional embodiments, the plate includes a top plate, a web plate, a water-passing baffle, and a bottom plate, wherein the thickness of the top plate is configured to be greater than 28 cm, the thickness of the web plate is configured to be greater than 50 cm, the thickness of the water-passing baffle is configured to be greater than 50 cm, and the thickness of the bottom plate is configured to be greater than 50 cm.

[0011] In some optional embodiments, the equation of the bottom curve of the tank body is: ,in, For the height of the root beam, The height of the closure section is m=2 if the main span is less than 150m, and m=1.5~1.8 if the main span is not less than 150m.

[0012] In some optional embodiments, the center-to-center distance of the double-limb thin-walled piers is determined by the following formula:

[0013]

[0014]

[0015]

[0016] in, The weight of the nth segment. The distance from the centroid of block n to the center of the pier top is [missing information]. Let H be the maximum unbalanced bending moment generated by the segment during construction, B be the length of the pier, I be the elastic section moment of the double-limb pier in the longitudinal direction, and W be the elastic section modulus of the double-limb pier in the longitudinal direction. This is the standard value for the tensile strength of the pier concrete.

[0017] In some alternative embodiments, the prestressed steel strands arranged longitudinally include top slab strands and web strands during the cantilever casting process, as well as side span closure strands and mid-span closure strands after closure.

[0018] In some optional embodiments, the cross-sectional areas of the top plate bundles and web plate bundles configured during the cantilever casting process satisfy:

[0019] in, F represents the line load on the concrete of the trench body, and F represents the concentrated load at the cantilever end, such as the wet weight of the cantilevered formwork and the concrete of the cantilevered segments. The distance from the centroid of block n to the center of the pier top is... The empirical coefficient is set between 0.85 and 0.95. The effective height of the cross section, The design strength of the steel strand.

[0020] In some alternative embodiments, the cross-sectional area of ​​the mid-span closure bundle satisfies: before water flow,

[0021] After the water supply was turned on,

[0022] in, For the line load of the concrete in the trench, For the water load of the tank body, The empirical coefficient is set between 0.85 and 0.95. The effective height of the cross section, For the design strength of the steel strand, For the side span, The main span.

[0023] In some alternative embodiments, the cross-sectional area of ​​the side span closure bundle satisfies: before water flow,

[0024] After the water supply was turned on,

[0025] in, For the line load of the concrete in the trench, For the water load of the tank body, The empirical coefficient is set between 0.85 and 0.95. The effective height of the cross section, For the design strength of the steel strand, For the side span, The main span.

[0026] Compared with the prior art, this application has the following advantages and beneficial effects: The design method for continuous rigid frame aqueducts provided in this application addresses the problems of low design efficiency and lack of general design methods and standard guidance in existing technologies. It systematically presents a series of detailed and operational design steps, from determining the construction location and span arrangement, to span arrangement, determining beam height, plate thickness, and segmentation, to configuring prestressed steel strands and constructing finite element model analysis. It provides a complete approach and methodology for the design of continuous rigid frame aqueducts, effectively improves design efficiency, solves the problem of lack of design basis, and helps to promote the standardization and normalization of continuous rigid frame aqueduct design. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the exemplary embodiments of this application, 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 this application 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: Figure 1 This is a schematic diagram of the design method for a continuous rigid frame aqueduct provided in an embodiment of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this application are only for explaining this application and are not intended to limit this application.

[0029] like Figure 1 As shown in the figure, this application provides a design method for a continuous rigid frame aqueduct, which includes the following: S1. Determine the construction location of the continuous rigid frame aqueduct, and formulate the span arrangement of the continuous rigid frame aqueduct based on the construction location.

[0030] The construction location of continuous rigid frame aqueducts is generally to cross valleys, rivers, routes, etc., and the layout of the aqueduct spans is related to the terrain it crosses.

[0031] S2. Determine the span arrangement, side span span, and main span span based on the preset range of the side-to-middle span ratio of the continuous rigid frame aqueduct.

[0032] The side-to-middle span ratio is typically taken as 0.5 to 0.7. In this embodiment, the side-to-middle span ratio is taken as follows: ,in, For the side span, The main span is determined first based on the terrain. For example, when an aqueduct crosses a valley, the usual design value is 100-180m. When an aqueduct crosses a river, the usual design value is 80-150m. Once the main span is determined, the side span can be determined based on the range of the side-to-middle span ratio.

[0033] In this embodiment of the application, the range of the side-to-span ratio is taken as follows: In this configuration, the side spans and the middle span exhibit better coordination, with their lengths being relatively close. This results in a more harmonious stress distribution when bearing loads, allowing the side spans to better share some of the load on the middle span, reducing its burden and thus improving the overall load-bearing capacity and stability of the continuous rigid frame aqueduct structure. Furthermore, during the aqueduct's operation, under conditions such as water pressure, wind loads, and seismic loads, the ratio of side spans to middle spans within this range ensures a more uniform distribution of internal forces, preventing excessive local stress, reducing the risk of structural cracking, and guaranteeing the aqueduct's safe operation. Additionally, the appropriate length ratio of side spans to middle spans facilitates the reuse and turnover of construction formwork, reducing the number of formwork disassemblies and adjustments, ensuring construction progress. During concrete pouring, the construction sequence and connection between the side spans and middle spans are smoother, which is beneficial for controlling construction quality and schedule.

[0034] S3. Determine the height of the root beam and the height of the closure section beam based on the main span and the preset range of the height-to-span ratio of the continuous rigid frame aqueduct. In this embodiment of the application, the height-to-span ratio includes the ratio of the root beam height to the main span and the ratio of the closure section beam height to the main span, and the range of values ​​for the height-to-span ratio is predetermined.

[0035] In conventional designs, the ratio of the root beam height to the main span is typically 1 / 20 to 1 / 15. In the embodiments of this application, the ratio of the root beam height to the main span is within a certain range. , The height of the root beam is within this range. This ensures that the root beam has sufficient height to resist large bending moments and shear forces. The root is a critical part of the aqueduct's load-bearing structure. Appropriately increasing the root beam height can effectively improve the structure's load-bearing capacity while avoiding material waste due to excessive beam height. For example, when the main span is 100 meters, the root beam height should be between 5.4 and 10.5 meters, with larger values ​​for smaller spans. This beam height can meet the structural load requirements during the service phase, ensuring the safe and stable operation of the aqueduct. At the same time, a moderate beam height can reduce the size and weight of the formwork, facilitating the operation and handling of construction personnel, and making it easier to select and arrange construction equipment, thus improving construction efficiency. Furthermore, the root is the connection point between the aqueduct and the piers. A larger beam height can improve the structure's resistance to overturning and sliding, ensuring the safety of the aqueduct under wind loads, seismic loads, and other conditions.

[0036] In conventional designs, the ratio of the closure segment beam height to the main span is typically 1 / 60 to 1 / 40. In the embodiments of this application, the ratio of the closure segment beam height to the main span is within a certain range. , The height of the closure segment is within a certain range. This range ensures the stability of the closure segment during construction while also meeting the structural load-bearing requirements during service. The closure segment is a crucial part of aqueduct construction. An appropriate height facilitates construction and also benefits the overall structural load-bearing capacity. Taking a main span of 100 meters as an example, the beam height of the closure segment can be taken within the range of 2.55 to 6.99 meters. For smaller spans, a larger value should be used. This height range allows the closure segment to smoothly connect with adjacent beam segments, forming a complete structural system, while ensuring construction quality.

[0037] S4. Determine the plate thickness range, the length of the cast-in-place section at the top of the pier, the length of the closure section, and the curve equation at the bottom of the trench, and divide the cantilever section into segments.

[0038] In this embodiment of the application, the plate includes a top plate, a web plate, a water-passing baffle, and a bottom plate, wherein the thickness of the top plate is configured to be greater than 28cm, the thickness of the web plate is configured to be greater than 50cm, the thickness of the water-passing baffle is configured to be greater than 50cm, and the thickness of the bottom plate is configured to be greater than 50cm.

[0039] In this embodiment, the length of the cast-in-place section at the top of the pier needs to meet the installation space requirements of the cantilevered formwork, and is usually configured to be 12m.

[0040] In this embodiment of the application, the closure segment length includes the mid-span closure segment length and the side-span closure segment length, both of which are typically configured to be 2m.

[0041] In this embodiment of the application, the equation of the curve at the bottom of the tank is: ,in, For the height of the root beam, For the closure section beam height, if the main span is less than 150m, then m=2; if the main span is not less than 150m, then m=1.5~1.8. By rationally designing the shape of the bottom of the aqueduct using a curve equation, the structural self-weight can be cleverly distributed along the curve, making the distribution of the structural self-weight more balanced in different parts, reducing excessive stress caused by self-weight concentration in certain parts, thereby improving the load-bearing capacity and stability of the entire structure. This curved shape can also change the distribution of wind load on the surface of the aqueduct, reducing the force of wind load on the structure, reducing wind vibration response, and thus improving the safety and stability of the aqueduct in strong winds.

[0042] In this embodiment of the application, when the cantilever section is segmented, the cantilever section near the root is short and can be segmented into sections of about 3m; the cantilever section far from the root is long and can be segmented into sections of about 4m; if the span is large, the middle sections can be segmented into sections of 3.5m in length.

[0043] S5. Determine the center-to-center distance of the two-limb thin-walled piers and the center-to-center distance of the two limbs; In this embodiment, the center-to-center distance of the double-limb thin-walled pier is determined by the following formula:

[0044]

[0045]

[0046]

[0047] in, The weight of the nth segment. The distance from the centroid of block n to the center of the pier top is [missing information]. Let H be the maximum unbalanced bending moment generated by the segment during construction, B be the length of the pier, I be the elastic section moment of the double-limb pier in the longitudinal direction, and W be the elastic section modulus of the double-limb pier in the longitudinal direction. This is the standard value for the tensile strength of the pier concrete.

[0048] S6. Prestressed steel strands are configured in the longitudinal and transverse directions for the continuous rigid frame aqueduct.

[0049] In this embodiment of the application, the longitudinal prestressed steel strands include the top slab strands and web strands during the cantilever casting process, as well as the side span closure strands and the middle span closure strands after closure.

[0050] The cross-sectional areas of the top slab bundles and web slab bundles configured during the cantilever casting process satisfy the following:

[0051] in, F represents the line load on the concrete of the trench body, and F represents the concentrated load at the cantilever end, such as the wet weight of the cantilevered formwork and the concrete of the cantilevered segments. The distance from the centroid of block n to the center of the pier top is... The empirical coefficient is set between 0.85 and 0.95. The effective height of the cross section, The design strength of the steel strand.

[0052] After closure, the prestressed steel strands need to meet the requirements before and after water supply. Before water supply, the cross-sectional areas of the top slab steel strands, web steel strands, and bottom slab steel strands at the mid-span section must meet the following requirements:

[0053] After water is supplied, the cross-sectional areas of the top plate tendons, web tendons, and bottom plate tendons at the mid-span section satisfy the following:

[0054] in, For the line load of the concrete in the trench, For the water load of the tank body, The empirical coefficient is set between 0.85 and 0.95. The effective height of the cross section, For the design strength of the steel strand, For the side span, The main span.

[0055] Before water flow, the cross-sectional areas of the top plate steel strands, web steel strands, and bottom plate steel strands at the maximum positive bending moment section of the side span satisfy the following:

[0056] After water flow, the cross-sectional area of ​​the side span closure bundle satisfies:

[0057] in, For the line load of the concrete in the trench, For the water load of the tank body, The empirical coefficient is set between 0.85 and 0.95. The effective height of the cross section, For the design strength of the steel strand, For the side span, The main span.

[0058] In this embodiment, the transverse steel strands are mainly divided into top plate transverse steel strands, bottom plate transverse steel strands, circumferential steel strands, and water-passing baffle transverse steel strands. The design of the transverse steel strands is mainly based on stress control.

[0059] S7. Construct a finite element model and perform finite element analysis.

[0060] Using the parameters or structural layout determined in steps S1 to S6, a three-dimensional model is established in the finite element analysis software. Different parameters are adjusted according to the numerical ranges in steps S1 to S6 using the finite element analysis software, and constraints such as crowd load, temperature, and concrete shrinkage and creep are added until the calculation results meet the specifications and expectations.

[0061] The design method for continuous rigid frame aqueducts provided in this application addresses the problems of low design efficiency and lack of general design methods and standard guidance in existing technologies. It systematically presents a series of detailed and operational design steps, from determining the construction location and span arrangement, to span arrangement, determining beam height, plate thickness, and segmentation, to configuring prestressed steel strands and constructing finite element model analysis. It provides a complete approach and methodology for the design of continuous rigid frame aqueducts, effectively improves design efficiency, solves the problem of lack of design basis, and helps to promote the standardization and normalization of continuous rigid frame aqueduct design.

[0062] The specific embodiments described above illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with some embodiments, this does not mean that the features of this application are limited to this embodiment. On the contrary, the purpose of describing the application in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of this application. To provide a thorough understanding of this application, many specific details are included in the above description. This application may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0063] It should be noted that in this specification, similar reference numerals and letters in the above figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this application, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0064] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A design method for a continuous rigid frame aqueduct, characterized in that, Includes the following: Determine the construction location of the continuous rigid frame aqueduct, and formulate the span arrangement of the continuous rigid frame aqueduct based on the construction location. The arrangement of the spans, the span of the side spans, and the span of the main span are determined according to the preset range of the side-to-middle span ratio of the continuous rigid frame aqueduct. The root beam height and closure section beam height are determined based on the main span and the pre-set range of the height-to-span ratio of the continuous rigid frame aqueduct. Determine the plate thickness range, the length of the cast-in-place section at the top of the pier, the length of the closure section, and the curve equation of the bottom of the trench, and then divide the cantilever section into segments. Determine the center-to-center distance of the two-limb thin-walled piers and the center-to-center distance of the two limbs; Prestressed steel strands are configured in both the longitudinal and transverse directions for continuous rigid frame aqueducts. Construct a finite element model and perform finite element analysis.

2. The design method for continuous rigid frame aqueducts according to claim 1, characterized in that, The range of the side span ratio ,in, For the side span, The main span.

3. The design method for continuous rigid frame aqueducts according to claim 1, characterized in that, The range of the height-to-span ratio includes the range of the ratio of the root beam height to the main span. and the range of beam height of the closure section to the span of the main span ,in, For the height of the root beam, The closure section is of high beam height.

4. The design method for continuous rigid frame aqueducts according to claim 1, characterized in that, The plate includes a top plate, a web plate, a water-passing baffle, and a bottom plate, wherein the thickness of the top plate is configured to be greater than 28cm, the thickness of the web plate is configured to be greater than 50cm, the thickness of the water-passing baffle is configured to be greater than 50cm, and the thickness of the bottom plate is configured to be greater than 50cm.

5. The design method for a continuous rigid frame aqueduct according to claim 1, characterized in that, The equation of the curve at the bottom of the tank is: ,in, For the height of the root beam, The height of the closure section is m = 2 if the main span is less than 150m, and m = 1.5~1.8 if the main span is not less than 150m.

6. The design method for continuous rigid frame aqueducts according to claim 1, characterized in that, The center-to-center distance of the double-limb thin-walled piers is determined by the following formula: in, The weight of the nth segment. The distance from the centroid of block n to the center of the pier top is [missing information]. Let H be the maximum unbalanced bending moment generated by the segment during construction, B be the length of the pier, I be the elastic section moment of the double-limb pier in the longitudinal direction, and W be the elastic section modulus of the double-limb pier in the longitudinal direction. This is the standard value for the tensile strength of the pier concrete.

7. The design method for continuous rigid frame aqueducts according to claim 1, characterized in that, The prestressed steel strands configured in the longitudinal direction include the top slab strands and web strands during the cantilever casting process, as well as the side span closure strands and mid-span closure strands after closure.

8. The design method for a continuous rigid frame aqueduct according to claim 7, characterized in that, The cross-sectional areas of the top slab bundles and web slab bundles configured during the cantilever casting process satisfy the following: in, F represents the line load on the concrete of the trench body, and F represents the concentrated load at the cantilever end, such as the wet weight of the cantilevered formwork and the concrete of the cantilevered segments. The distance from the centroid of block n to the center of the pier top is... The empirical coefficient is set between 0.85 and 0.

95. The effective height of the cross section, The design strength of the steel strand.

9. The design method for a continuous rigid frame aqueduct according to claim 7, characterized in that, The cross-sectional area of ​​the mid-span closure bundle satisfies the following condition before water flow: After the water supply was turned on, in, For the line load of the concrete in the trench, For the water load of the tank body, The empirical coefficient is set between 0.85 and 0.

95. The effective height of the cross section, For the design strength of the steel strand, For the side span, The main span.

10. The design method for a continuous rigid frame aqueduct according to claim 7, characterized in that, The cross-sectional area of ​​the side span closure bundle satisfies the following condition before water flow: After the water supply was turned on, in, For the line load of the concrete in the trench, For the water load of the tank body, The empirical coefficient is set between 0.85 and 0.

95. The effective height of the cross section, For the design strength of the steel strand, For the side span, The main span.

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