Combined space arch rib structure of inclined arch curved beam and method

Abstract

The invention relates to a combined space arch rib structure of an inclined arch curved beam and a method, and belongs to the technical field of large-span inclined arch curved beams, the combined space arch rib structure of the inclined arch curved beam is adopted, loads are effectively dispersed and transmitted, pressure on the ground is reduced, and then a steel structure arch rib body is combined with a concrete filling unit, so that the large-span inclined arch curved beam is formed. Good toughness of a steel structure can be utilized, the high compressive strength of concrete can be exerted, the positioning assemblies arranged in the steel structure arch rib body can effectively restrain sliding of the concrete filling units, and the overall stability of the structure is ensured; the concrete filling unit adopts the combination of various modes such as full filling, semi-filling, inner side filling, outer side filling and central filling, and can be optimized according to different positions and structure requirements, so that the rigidity of the structure is ensured, unnecessary material waste is avoided, and the problem of contradiction between the stability and the rigidity of the bridge under the soft terrain is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of large-span oblique arched beams, and in particular relates to a combined spatial arch rib structure of an oblique arched beam and a method thereof. Background Art

[0002] In the field of bridge engineering, large-span inclined arch curved beam structures are very popular because they can provide good spanning capacity and have good wind resistance. However, when building such bridges in areas with soft geology, traditional designs still face some challenges. For example, some current curved beam and inclined arch bridges usually enhance the overall structural strength through the consolidation design of piers and arch feet, but the soft foundation is difficult to provide sufficient lateral support. When the total weight of the arch ribs exceeds the critical value, the pile foundation is prone to lateral loosening, resulting in reduced bridge stability and even the risk of collapse. If the weight of the arch ribs is simply reduced, although the pile foundation load can be reduced, the arch rib stiffness will be weakened, causing deformation or damage to the multi-structure connections and core stress areas (such as the arch-beam joint) due to insufficient stiffness, which also threatens the safety of the bridge.

[0003] In order to overcome the problems existing in the construction of curved beam and inclined arch bridges in soft geological areas, some current curved beam and inclined arch bridges use concrete composite arch rib technology, in which some composite arch ribs are filled with full-section concrete or partially poured. Although this design can improve stiffness, the filling method is fixed and cannot be dynamically adjusted according to geological conditions. For example, although full filling improves stiffness, it greatly increases the thrust of the arch foot, aggravating the lateral instability of the pile foundation; while partial filling reduces weight, it may lead to uneven stiffness distribution and cause local stress concentration. In addition, the existing technology lacks a systematic design method for the relationship between concrete filling area and geological conditions, making it difficult to balance stiffness requirements with pile foundation bearing capacity limitations. Therefore, there is an urgent need for a combined structure and method that can dynamically optimize the arch rib filling strategy according to geological conditions to resolve the contradiction between bridge stability and stiffness in soft terrain. To this end, a combined spatial arch rib structure and method for inclined arch curved beams are proposed. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a combined spatial arch rib structure of inclined arch curved beams and a method thereof, which solves the contradiction between stability and stiffness of bridges under soft terrain in the prior art.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A combined spatial arch rib structure of an oblique arch curved beam comprises a steel structure arch rib body, a plurality of concrete filling units and a positioning assembly arranged inside the steel structure arch rib body, wherein a continuous cavity is formed inside the steel structure arch rib body, a plurality of fulcrums are arranged in the cavity formed inside the steel structure arch rib body, a plurality of the concrete filling units are discretely distributed on the plurality of fulcrums, the positioning assembly is used to constrain the slippage of the concrete filling units, and the concrete filling units adopt differentiated filling modes, which are selected from at least three combinations of full filling, half filling, inner filling, outer filling and central filling.

[0007] As a further solution of the present invention, the positioning structure includes welding studs and stiffening partitions, the welding studs and stiffening partitions cooperate with each other to constrain the concrete filling unit, and the stiffening partitions are provided with anti-slip protrusions.

[0008] As a further solution of the present invention, the full filling area is located in the arch foot to arch beam junction section, and its concrete filling rate is 90%-100%; the semi-filling area is located in the mid-span area of ​​the arch rib, and its concrete filling rate is 40%-60%. The inner filling area and the outer filling area correspond to the tensile side and the compressive side of the arch rib respectively, and the filling rate is adjusted according to the bending moment distribution gradient.

[0009] As a further solution of the present invention, the welding studs are distributed in a matrix, the stiffening partitions are arranged at intervals along the longitudinal direction of the arch rib, and the welding studs and the stiffening partitions are arranged coplanarly.

[0010] As a further solution of the present invention, the outer wall of the steel box arch rib body is wrapped with a high-performance concrete layer with a thickness of 80-120 mm.

[0011] A design method for a combined spatial arch rib of an oblique arch curved beam comprises the following steps:

[0012] S1: Based on the bridge design load and geological survey data, determine the target filling amount Q0 and filling method of each stress zone of the arch rib under the standard support force;

[0013] S2: Obtain the foundation bearing capacity coefficient k of the actual construction area and calculate the corrected filling amount Q using the formula Q = Q0 × [1 + α (1-k)], where α is the geological correction coefficient;

[0014] S3: Based on the corrected filling amount Q, one or more combinations of full filling, half filling, inner filling, outer filling, or central filling are selected;

[0015] S4: Pre-install the positioning structure in the steel box arch rib and pour concrete according to the filling method determined in step S3.

[0016] As a further solution of the present invention, in step S3, when the actual foundation bearing capacity k is less than 0.6, a combination of full filling and outer filling is adopted; when 0.6≤k<0.8, a combination of half filling and inner filling is adopted; when k≥0.8, a central filling method is adopted.

[0017] As a further solution of the present invention, in step S4, the concrete pouring adopts a segmented pouring process, the pouring sequence is advanced from the arch foot to the arch top, and the filling density is monitored in real time.

[0018] As a further solution of the present invention, step S5 is also included: after the construction is completed, the arch rib strain and pile foundation displacement are monitored by optical fiber sensors. If the data exceeds the limit, micro-expansive concrete is additionally poured in the corresponding partition.

[0019] The beneficial effects of the present invention are:

[0020] By adopting a combined spatial arch rib structure of inclined arch curved beams, the load is effectively dispersed and transmitted, reducing the pressure on the ground. Then, the steel structure arch rib body is combined with the concrete filling unit to utilize the good toughness of the steel structure and the high compressive strength of the concrete. The positioning components set inside the steel structure arch rib body can effectively restrain the slippage of the concrete filling unit and ensure the overall stability of the structure. The concrete filling unit adopts a combination of various modes such as full filling, half filling, inner filling, outer filling and central filling, which can be optimized according to different positions and structural requirements. It not only ensures the rigidity of the structure, but also avoids unnecessary waste of materials, and solves the contradiction between the stability and rigidity of the bridge under soft terrain. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the oblique arch curved beam and arch rib structure of the present invention;

[0023] Figure 2 This is a flow chart of the combined spatial arch rib design method of the oblique arch curved beam of the present invention.

[0024] Description of main component symbols:

[0025] In the figure: 1. Steel structure arch rib body; 2. Arch foot. DETAILED DESCRIPTION

[0026] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0027] See also Figure 1 - Figure 2 This embodiment provides a combined spatial arch rib structure of an oblique arch curved beam, including a steel structure arch rib body 1, a plurality of concrete filling units and a positioning component arranged inside the steel structure arch rib body 1. A continuous cavity is formed inside the steel structure arch rib body 1, and a plurality of fulcrums are arranged in the cavity formed inside the steel structure arch rib body 1. The plurality of concrete filling units are discretely distributed on the plurality of fulcrums. The positioning component is used to constrain the slippage of the concrete filling units. The concrete filling units adopt a differentiated filling mode, and the filling mode is selected from at least three combinations of full filling, half filling, inner filling, outer filling and central filling.

[0028] Currently, some curved-beam and inclined-arch bridges use concrete composite arch rib technology, in which some composite arch ribs are filled with full-section concrete or partially poured. Although this design can improve stiffness, the filling method is fixed and cannot be dynamically adjusted according to geological conditions. For example, although full filling improves stiffness, it significantly increases the thrust of the arch foot 2, exacerbating lateral instability of the pile foundation. While partial filling reduces weight, it may lead to uneven stiffness distribution and cause local stress concentration. In addition, existing technologies lack a systematic design method for the relationship between concrete filling areas and geological conditions, making it difficult to balance stiffness requirements with the bearing capacity limitations of the pile foundation.

[0029] In order to solve the above problems, in this embodiment, a combined spatial arch rib structure of inclined arch curved beams is adopted to effectively disperse and transfer the load and reduce the pressure on the ground. Then, the steel structure arch rib body 1 is combined with the concrete filling unit to utilize the good toughness of the steel structure and the high compressive strength of the concrete. The positioning component arranged inside the steel structure arch rib body 1 can effectively restrain the slippage of the concrete filling unit and ensure the overall stability of the structure. The concrete filling unit adopts a combination of various modes such as full filling, half filling, inner filling, outer filling and central filling, which can be optimized according to different positions and structural requirements, thereby ensuring the stiffness of the structure and avoiding unnecessary waste of materials, thereby solving the contradiction between the stability and stiffness of the bridge under soft terrain.

[0030] Continuing from the previous embodiment, in order to further improve the stability of the bridge, in one embodiment, the positioning structure includes welded studs and stiffening partitions. The welded studs and stiffening partitions cooperate with each other to constrain the concrete filling unit. Anti-slip protrusions are provided on the stiffening partitions. The welded studs are distributed in a matrix manner. The stiffening partitions are arranged at intervals along the longitudinal direction of the arch ribs. The welded studs and the stiffening partitions are arranged in the same plane. The combined design of the welded studs and the stiffening partitions effectively prevents the concrete filling unit from slipping during the construction or use stage through the dual effects of mechanical engagement and spatial constraint. The longitudinal spacing of the stiffening partitions not only improves the torsional stiffness of the arch ribs, but also facilitates the segmented pouring of concrete during construction. The anti-slip protrusions further enhance the interfacial bonding between the concrete and the steel box, avoiding interface peeling due to vibration or load changes.

[0031] In order to better solve the problem of excessive deadweight caused by full filling and avoid uneven stiffness caused by local filling, in one embodiment, the filling area of ​​the steel box arch rib is divided into the following according to the stress characteristics: the full filling area is located in the arch foot 2 to the arch beam junction section, and its concrete filling rate is 90%-100%. This area bears the maximum axial pressure and bending moment. The high filling rate can significantly improve the local stiffness and compressive strength, and reduce the lateral impact of the arch foot 2 thrust on the pile foundation; the semi-filling area is located in the mid-span area of ​​the arch rib, and its concrete filling rate is 40%-60%. The mid-span area is mainly subjected to bending. Moderate filling can ensure stiffness and avoid excessive deadweight. Leading to pile foundation overload; the inner filling area and the outer filling area correspond to the tensile side and the compressive side of the arch rib respectively, and the filling rate is adjusted according to the bending moment distribution gradient, which correspond to the tensile side and the compressive side of the arch rib respectively. The filling rate is dynamically adjusted according to the bending moment distribution gradient (for example, the filling rate on the compression side is increased to 70%, and the tensile side is reduced to 50%) to achieve asymmetric optimization of stiffness and balance local stress concentration; through differentiated filling strategies, it not only solves the problem of excessive deadweight caused by full filling, but also avoids the uneven stiffness caused by local filling. The bending moment gradient adjustment further optimizes the material utilization rate, thereby improving the overall stability of the arch rib under soft foundation.

[0032] In order to reduce the weight of the structure while improving stability, in one embodiment, the outer wall of the steel box arch rib body is wrapped with a high-performance concrete layer with a thickness of 80-120 mm. The high-performance concrete layer here is a UHPC layer, which is fixed to the steel box by pre-embedded connectors. The UHPC layer covers the underwater area and corrosion-prone parts of the entire length of the arch rib. The high density and impermeability of the UHPC layer effectively isolate the steel box from the erosion of moisture and corrosive media, thereby extending the life of the structure. At the same time, the high strength of UHPC (compressive strength ≥120 MPa) improves the local collision resistance of the arch rib and reduces the risk of ship collision. The setting of the connector ensures that the UHPC layer and the steel box are synergistically stressed to avoid interface slippage.

[0033] A design method for a combined spatial arch rib of an oblique arch curved beam comprises the following steps:

[0034] S1: Based on the bridge design load and geological survey data, determine the target filling amount Q0 and filling method of each stress zone of the arch rib under the standard support force;

[0035] S2: Obtain the foundation bearing capacity coefficient k of the actual construction area and calculate the corrected filling amount Q using the formula Q = Q0 × [1 + α (1-k)], where α is the geological correction factor. Through steps S1 and S2, this method can determine the filling amount based on the bridge design load and the geological conditions of the actual construction area, making the design more flexible and able to adapt to complex and changing geological environments.

[0036] S3: Based on the modified filling amount Q, select one or more combinations of full filling, half filling, inner filling, outer filling, or central filling. Selecting the appropriate filling method based on the modified filling amount Q ensures that the filling amount of the arch rib is reasonably distributed in each load-bearing zone, thereby improving the stability and bearing capacity of the entire bridge structure, ensuring uniform force on each part of the arch rib, and avoiding structural damage due to excessive local force.

[0037] S4: Pre-install the positioning structure in the steel box arch rib and pour concrete according to the filling method determined in step S3. By accurately calculating and selecting the filling method, the material can be maximized and waste can be avoided, while ensuring the reliability and economy of the structure.

[0038] The method further includes step S5: after the construction is completed, the arch rib strain and pile foundation displacement are monitored by optical fiber sensors. If the data exceeds the limit, micro-expansive concrete is additionally poured in the corresponding partition.

[0039] It should be noted that the target fill volume calculation is based on the finite element model, and the bridge design load (such as crowd load 4.0kN / m 2 ) and standard geological parameters, iteratively adjust the filling amount of each partition until the convergence conditions of pile foundation lateral displacement ≤ 5mm and arch rib deflection ≤ L / 1500 (L is the arch span) are met. Geological correction is to obtain the actual foundation bearing capacity coefficient k (k = actual bearing capacity / standard bearing capacity) through on-site investigation, and substitute it into the formula Q = Q0 × [1 + α (1-k)] to calculate the corrected filling amount. The value of the geological correction coefficient α is determined according to the range of k: when k < 0.7, α = 0.8 (soft soil foundation requires a significant increase in filling amount to compensate for stiffness); when 0.7 ≤ k < 0.9, α = 0.5; when k ≥ 0.9, α = 0.2 (hard foundation can moderately reduce the filling amount);

[0040] When selecting the filling method, if k < 0.6, a combination of full filling (arch foot 2) and outer filling (compression side) is used to prioritize anti-thrust capability. If k < 0.6 and k < 0.8, a combination of half filling (mid-span) and inner filling (tension side) is used to balance stiffness and deadweight. If k ≥ 0.8, central filling (core area) is used to reduce lateral loads on the pile foundation. The filling amount is dynamically adjusted through a quantitative formula, addressing the blindness of traditional empirical methods. For example, in a soft soil foundation with k = 0.5, the filling amount is increased by 40% compared to the standard value, significantly improving pile foundation stability. In a hard foundation with k = 0.9, the filling amount is only 82% of the standard value, saving material costs.

[0041] In addition, during segmented pouring, concrete is poured in segments from the arch foot 2 to the arch top, with each segment being 4-6m long. A high-frequency vibrator is used during pouring to ensure density, and an ultrasonic detector is used to monitor the filling quality in real time (density ≥ 98% is qualified). After construction is completed, fiber optic sensors are embedded in key parts of the arch rib (such as the arch foot 2 and the mid-span) to monitor strain and pile foundation displacement in real time. If the data exceeds the limit (such as strain exceeding 2000με or displacement > 10mm), micro-expansion concrete (expansion rate 0.02%-0.05%) is added to the corresponding partition to compensate for shrinkage cracks and restore rigidity. The segmented pouring avoids the deformation of the formwork caused by the deadweight of concrete and ensures geometric accuracy. The real-time monitoring and compensation pouring technology reduces the risk of structural failure. It is particularly suitable for cross-river bridges with complex geological conditions. By iteratively adjusting the filling amount, the lateral displacement of the pile foundation and the arch rib deflection are ensured to be within a safe range, thereby improving the overall stability and safety of the bridge. This design can adapt to different geological conditions, especially in complex geological conditions such as soft soil foundations and hard soil foundations. The segmented pouring and supplementary pouring of micro-expansive concrete can effectively control the formwork deformation and shrinkage cracks caused by the deadweight of concrete.

[0042] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A combined spatial arch rib structure of oblique arch curved beams, characterized in that: It includes a steel structure arch rib body, several concrete filling units and a positioning component arranged inside the steel structure arch rib body. A continuous cavity is formed inside the steel structure arch rib body. Several fulcrums are set in the cavity formed inside the steel structure arch rib body. Several concrete filling units are discretely distributed on the several fulcrums. The positioning component is used to restrain the slippage of the concrete filling unit. The concrete filling unit adopts a differentiated filling mode, and the filling mode is selected from at least three combinations of full filling, half filling, inner filling, outer filling and central filling.

2. The combined spatial arch rib structure and method of the oblique arch curved beam according to claim 1, characterized in that: The positioning structure includes welding studs and stiffening partitions, the welding studs and stiffening partitions cooperate with each other to constrain the concrete filling unit, and the stiffening partitions are provided with anti-slip protrusions.

3. The combined spatial arch rib structure of the oblique arch curved beam according to claim 1, characterized in that: The full filling area is located in the section from the arch foot to the arch beam junction, and its concrete filling rate is 90%-100%; the semi-filling area is located in the mid-span area of ​​the arch rib, and its concrete filling rate is 40%-60%. The inner filling area and the outer filling area correspond to the tensile side and the compressive side of the arch rib respectively, and the filling rate is adjusted according to the bending moment distribution gradient.

4. The combined spatial arch rib structure of the oblique arch curved beam according to claim 2, characterized in that: The welding studs are distributed in a matrix pattern, the stiffening partitions are arranged at intervals along the longitudinal direction of the arch ribs, and the welding studs and the stiffening partitions are arranged in the same plane.

5. The combined spatial arch rib structure of the oblique arch curved beam according to claim 1, characterized in that: The outer wall of the steel box arch rib body is wrapped with a high-performance concrete layer with a thickness of 80-120 mm.

6. A design method for a combined spatial arch rib of an oblique arched beam, based on the combined spatial arch rib structure of an oblique arched beam according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Based on the bridge design load and geological survey data, determine the target filling amount Q0 and filling method of each stress zone of the arch rib under the standard support force; S2: Obtain the foundation bearing capacity coefficient k of the actual construction area and calculate the corrected filling amount Q using the formula Q = Q0 × [1 + α (1-k)], where α is the geological correction coefficient; S3: Based on the corrected filling amount Q, one or more combinations of full filling, half filling, inner filling, outer filling, or central filling are selected; S4: Pre-install the positioning structure in the steel box arch rib and pour concrete according to the filling method determined in step S3.

7. The design method for combined spatial arch ribs of an oblique arch curved beam according to claim 6, characterized in that: In step S3, when the actual foundation bearing capacity k is less than 0.6, a combination of full filling and outer filling is adopted; when 0.6≤k<0.8, a combination of half filling and inner filling is adopted; when k≥0.8, a central filling is adopted.

8. The method for designing combined spatial arch ribs of an oblique arch curved beam according to claim 6, characterized in that: In step S4, concrete pouring adopts a segmented pouring process, the pouring sequence is advanced from the arch foot to the arch top, and the filling density is monitored in real time.

9. The method for designing combined spatial arch ribs of an oblique arch curved beam according to claim 6, characterized in that: The method further includes step S5: after the construction is completed, the arch rib strain and pile foundation displacement are monitored by optical fiber sensors. If the data exceeds the limit, micro-expansive concrete is additionally poured in the corresponding partition.

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