Combined spatial arch rib structure and method of skew arch curved beam

Abstract

The present application relates to a kind of combination space arch rib structure and method of skew arch curved beam, belong to large-span skew arch curved beam technical field, by adopting the combination space arch rib structure of skew arch curved beam, effectively disperses and transmits load, reduce the pressure to ground, then using the way that steel structure arch rib body is combined with concrete filling unit, both can utilize the good toughness of steel structure, also can exert the high compressive strength of concrete, the positioning assembly set in the interior of steel structure arch rib body can effectively constrain the slippage of concrete filling unit, ensure the overall stability of structure, concrete filling unit adopts the combination of full filling, half filling, inside filling, outside filling and central filling etc., can be optimized according to different position and structure demand, both ensure the rigidity of structure, also avoid unnecessary material waste, solve the bridge stability and rigidity contradiction problem under soft terrain.

Description

Technical Field

[0001] This invention belongs to the technical field of large-span inclined arch curved beams, specifically relating to a combined spatial arch rib structure and method for inclined arch curved beams. Background Technology

[0002] In the field of bridge engineering, long-span inclined arch and curved beam structures are very popular due to their excellent spanning capacity and good wind resistance. However, traditional designs still face some challenges when constructing such bridges in areas with soft soil. For example, some curved beam and inclined arch bridges currently enhance the overall structural strength through the consolidation design of piers and arch feet. However, soft foundations cannot provide sufficient lateral support. When the total weight of the arch ribs exceeds the critical value, the pile foundation is prone to lateral loosening, leading to a decrease in bridge stability or even the risk of collapse. Simply reducing the weight of the arch ribs can reduce the load on the pile foundation, but it will weaken the stiffness of the arch ribs. This will cause deformation or damage at the joints of multiple structures and the core stress areas (such as the arch-beam joint) due to insufficient stiffness, which also threatens the safety of the bridge.

[0003] To overcome the problems encountered when constructing curved beam and inclined arch bridges in areas with soft geological conditions, some current curved beam and inclined arch bridges employ composite concrete arch rib technology, which involves filling part of the composite arch rib with full-section concrete or partial grouting. While this design improves stiffness, the filling method is fixed and cannot be dynamically adjusted according to geological conditions. For example, while full filling increases stiffness, it significantly increases the thrust at the arch foot, exacerbating lateral instability of the pile foundation; while partial filling reduces weight, it may lead to uneven stiffness distribution and local stress concentration. Furthermore, existing technologies lack a systematic design method that correlates the concrete filling area with geological conditions, making it difficult to balance stiffness requirements with pile foundation bearing capacity limitations. Therefore, there is an urgent need for a composite 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 address this, a composite spatial arch rib structure and method for inclined arch and curved beam bridges is proposed. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a combined spatial arch rib structure and method for inclined arch curved beams, resolving the contradiction between bridge stability and stiffness in soft terrain in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A combined spatial arch rib structure of inclined arch and curved beam includes a steel arch rib body, several concrete filling units, and a positioning component disposed inside the steel arch rib body. The steel arch rib body forms a continuous cavity, and several force points are set in the cavity. The several concrete filling units are discretely distributed on the several force points. 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.

[0007] As a further embodiment of the present invention, the positioning structure includes welded studs and stiffening baffles, the welded studs and stiffening baffles cooperate to constrain the concrete filling unit, and the stiffening baffles are provided with anti-slip protrusions.

[0008] As a further embodiment of the present invention, the fully filled area is located in the section from the arch foot to the arch beam joint, and its concrete filling rate is 90%-100%; the semi-filled area is located in the mid-span region of the arch rib, and its concrete filling rate is 40%-60%; the inner filling area and the outer filling area correspond to the tension side and the compression side of the arch rib, respectively, and the filling rate is adjusted according to the bending moment distribution gradient.

[0009] As a further embodiment of the present invention, the welded studs are distributed in a matrix, the stiffening diaphragms are arranged at intervals along the longitudinal direction of the arch rib, and the welded studs and stiffening diaphragms are arranged in the same plane.

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

[0011] A design method for a combined spatial arch rib of a sloping arch and curved beam includes the following steps:

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

[0013] S2: Obtain the 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 fill amount Q, select one or more combinations of full fill, half fill, inner fill, outer fill, or center fill;

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

[0016] As a further embodiment of the present invention, in step S3, when the actual foundation bearing capacity k < 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; and when k ≥ 0.8, a central filling method is adopted.

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

[0018] As a further aspect of the present invention, step S5 is also included: after construction is completed, the arch rib strain and pile foundation displacement are monitored by fiber optic sensors. If the data exceeds the limit, micro-expansion concrete is added to the corresponding zone.

[0019] The beneficial effects of this invention are as follows:

[0020] By employing a combined spatial arch rib structure of inclined arch and curved beam, the load is effectively dispersed and transferred, reducing the pressure on the ground. Then, by combining the steel arch rib body with concrete infill units, the good toughness of the steel structure and the high compressive strength of the concrete can be utilized. The positioning components set inside the steel arch rib body can effectively restrain the slippage of the concrete infill units, ensuring the overall stability of the structure. The concrete infill units adopt 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 locations and structural requirements. This ensures the stiffness of the structure and avoids unnecessary material waste, solving the contradiction between bridge stability and stiffness in soft terrain. Attached Figure Description

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

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

[0023] Figure 2 This is a flowchart of the combined spatial arch rib design method for the inclined arch curved beam of the present invention.

[0024] Explanation of key component symbols:

[0025] In the diagram: 1. The steel arch rib body; 2. The arch foot. Detailed Implementation

[0026] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0027] Please see Figure 1 - Figure 2 This embodiment provides a combined spatial arch rib structure of inclined arch and curved beam, including a steel arch rib body 1, several concrete filling units, and a positioning component disposed inside the steel arch rib body 1. A continuous cavity is formed inside the steel arch rib body 1, and several force points are set in the cavity formed inside the steel arch rib body 1. Several concrete filling units are discretely distributed on several force points. 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 have adopted concrete composite arch rib technology, which involves filling part of the composite arch rib with full-section concrete or grouting it locally. 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 increases stiffness, it significantly increases the thrust at the arch foot, exacerbating the lateral instability of the pile foundation. On the other hand, although 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 that relates the concrete filling area to geological conditions, making it difficult to balance stiffness requirements with the bearing capacity limitations of the pile foundation.

[0029] To address the aforementioned issues, this embodiment employs a combined spatial arch rib structure with inclined arches and curved beams to effectively distribute and transfer loads, reducing pressure on the ground. The combination of the steel arch rib body 1 and concrete filling units leverages both the excellent toughness of the steel structure and the high compressive strength of the concrete. Positioning components within the steel arch rib body 1 effectively constrain the slippage of the concrete filling units, ensuring overall structural stability. The concrete filling units utilize a combination of full-fill, half-fill, inner-side-fill, outer-side-fill, and central-fill modes, allowing for optimization based on different locations and structural requirements. This approach ensures structural rigidity while avoiding unnecessary material waste, resolving the contradiction between bridge stability and rigidity in soft terrain.

[0030] Following the previous embodiment, to further improve bridge stability, in one embodiment, the positioning structure includes welded studs and stiffening diaphragms. The welded studs and stiffening diaphragms cooperate to constrain the concrete filling units. The stiffening diaphragms are provided with anti-slip protrusions. The welded studs are distributed in a matrix. The stiffening diaphragms are arranged at intervals along the longitudinal direction of the arch rib. The welded studs and stiffening diaphragms are set in the same plane. The combined design of the welded studs and stiffening diaphragms effectively prevents the slippage of the concrete filling units during construction or use through the dual effects of mechanical interlocking and spatial constraint. The longitudinally spaced arrangement of the stiffening diaphragms not only improves the torsional stiffness of the arch rib but also facilitates the segmented pouring of concrete during construction. The anti-slip protrusions further enhance the interfacial adhesion between the concrete and the steel box, avoiding interfacial peeling caused by vibration or load changes.

[0031] To better address the issue of excessive self-weight caused by full filling while avoiding uneven stiffness due to partial filling, in one embodiment, the filling area of ​​the steel box arch rib is divided according to its stress characteristics: a fully filled area located from arch foot 2 to the arch-beam junction, with a concrete filling rate of 90%-100%, where the maximum axial pressure and bending moment are borne; a high filling rate can significantly improve local stiffness and compressive strength, and reduce the lateral impact of the thrust at arch foot 2 on the pile foundation; and a semi-filled area located in the mid-span region of the arch rib, with a concrete filling rate of 40%-60%, where bending is the primary stress, and moderate filling ensures both stiffness and avoids excessive self-weight. This leads to pile foundation overload; the inner and outer filling zones correspond to the tension and compression sides of the arch rib, respectively, and the filling rate is adjusted according to the bending moment distribution gradient. The filling rate is dynamically adjusted according to the bending moment distribution gradient (for example, the filling rate of the compression side is increased to 70%, and the filling rate of the tension side is reduced to 50%) to achieve asymmetric optimization of stiffness and balance local stress concentration. Through the differentiated filling strategy, the problem of excessive self-weight caused by full filling is solved, and the stiffness unevenness caused by local filling is avoided. The bending moment gradient adjustment further optimizes the material utilization rate, thereby improving the overall stability of the arch rib under soft foundation.

[0032] To reduce structural weight while improving stability, in one embodiment, the outer wall of the steel box arch rib is wrapped with a high-performance concrete layer with a thickness of 80-120mm. This high-performance concrete layer is a UHPC layer, which is fixed to the steel box through pre-embedded connectors. The UHPC layer covers the underwater area and easily corroded parts of the entire arch rib. The high density and impermeability of the UHPC layer effectively isolate moisture and corrosive media from eroding the steel box, extending the structural life. At the same time, the high strength of UHPC (compressive strength ≥120MPa) improves the local impact resistance of the arch rib and reduces the risk of ship collisions. The connectors ensure that the UHPC layer and the steel box share the load together, avoiding interface slippage.

[0033] A design method for a combined spatial arch rib of a sloping arch and curved beam includes the following steps:

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

[0035] S2: Obtain the 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; 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, which makes the design more flexible and adaptable to complex and changing geological environments;

[0036] S3: Based on the corrected 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 according to the corrected filling amount Q can ensure that the filling amount of the arch rib is reasonably distributed in each stress zone, thereby improving the stability and load-bearing capacity of the entire bridge structure, ensuring uniform stress on each part of the arch rib, and avoiding structural damage due to excessive local stress.

[0037] S4: Pre-install the positioning structure inside 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 used to the maximum extent, avoiding waste, while ensuring the reliability and economy of the structure.

[0038] It also includes step S5: After construction is completed, the arch rib strain and pile foundation displacement are monitored by fiber optic sensors. If the data exceeds the limit, micro-expansion concrete is poured in the corresponding zone.

[0039] It should be noted that the target fill volume calculation is based on a finite element model, with the bridge design load (such as a crowd load of 4.0 kN / m) as input. 2 Based on the standard geological parameters, the filling volume of each zone is iteratively adjusted 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 achieved by obtaining the actual foundation bearing capacity coefficient k (k = actual bearing capacity / standard bearing capacity) through on-site investigation and substituting it into the formula Q = Q0 × [1 + α(1-k)] to calculate the corrected filling volume. 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 foundations need to significantly increase the filling volume to compensate for stiffness); when 0.7 ≤ k < 0.9, α = 0.5; when k ≥ 0.9, α = 0.2 (hard soil foundations can moderately reduce the filling volume).

[0040] When selecting the filling method, for k < 0.6: a combination of full filling (arch foot 2) + outer filling (compression side) is used to prioritize enhancing the lateral resistance; for 0.6 ≤ k < 0.8: a combination of half filling (mid-span) + inner filling (tension side) is used to balance stiffness and self-weight; for k ≥ 0.8: central filling (core area) is used to reduce the lateral load on the pile foundation. The filling amount is dynamically adjusted through a quantitative formula, which solves the blindness of the traditional empirical method. For example, in soft soil foundation with k = 0.5, the filling amount is increased by 40% compared to the standard value, which significantly improves the stability of the pile foundation; while in hard soil foundation with k = 0.9, the filling amount only needs to be 82% of the standard value, saving material costs.

[0041] In addition, during segmented pouring, the concrete is poured in sections from arch foot 2 to arch crown, each section being 4-6m long. High-frequency vibrators are used to ensure compaction during pouring, and ultrasonic testing is used to monitor the filling quality in real time (compactness ≥98% is considered acceptable). After construction, fiber optic sensors are pre-embedded in key parts of the arch ribs (such as arch foot 2 and mid-span) to monitor strain and pile displacement in real time. If the data exceeds limits (e.g., strain exceeds 2000με or displacement >10mm), micro-expansion concrete (expansion rate 0.02%-0.05%) is poured in the corresponding section to compensate for shrinkage cracks and restore rigidity. The segmented pouring method avoids formwork deformation caused by the self-weight of concrete, ensuring geometric accuracy. Real-time monitoring and compensation pouring technology reduces the risk of structural failure, making it particularly suitable for cross-river bridges with complex geological conditions. By iteratively adjusting the filling volume, it ensures that the lateral displacement of the pile foundation and the deflection of the arch rib are within a safe range, thereby improving the overall stability and safety of the bridge. This design can adapt to different geological conditions, especially under complex geological conditions such as soft soil foundation and hard foundation. Through segmented pouring and supplementary pouring with micro-expansion concrete, it effectively controls formwork deformation and shrinkage cracks caused by the self-weight of concrete.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A design method for a combined spatial arch rib of a sloping arch-curved beam, based on a combined spatial arch rib structure of a sloping arch-curved beam, characterized in that, The arch rib structure includes a steel arch rib body, several concrete filling units, and a positioning component disposed inside the steel arch rib body. The steel arch rib body forms a continuous cavity, and several force points are set in the cavity. The several concrete filling units are discretely distributed on the several force points. 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. The fully filled area is located from the arch foot to the arch beam joint section, and its concrete filling rate is 90%-100%; the semi-filled area is located in the mid-span area of ​​the arch rib, and its concrete filling rate is 40%-60%; the inner and outer filling areas correspond to the tension side and compression side of the arch rib, respectively, and the filling rate is adjusted according to the bending moment distribution gradient. The design method includes the following steps: S1: Based on the bridge design load and geological survey data, determine the target filling amount Q0 and filling method for each stress zone of the arch rib under standard support force; S2: Obtain the 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 fill amount Q, select one or more combinations of full fill, half fill, inner fill, outer fill, and central fill; S4: Pre-install positioning components inside the steel structure arch ribs, and pour concrete according to the filling method determined in step S3; In step S3, when the actual foundation bearing capacity k < 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; and when k ≥ 0.8, a central filling method is adopted. By selecting the appropriate filling method based on the corrected filling amount Q, it can be ensured that the filling amount of the arch rib is reasonably distributed in each stress zone, thereby improving the stability and load-bearing capacity of the entire bridge structure. It can also ensure that the stress on each part of the arch rib is uniform, avoiding structural damage caused by excessive local stress.

2. The method for designing a combined spatial arch rib of a sloping arch curved beam according to claim 1, characterized in that, The positioning component includes welded studs and stiffening baffles, which cooperate to constrain the concrete filling unit. The stiffening baffles are provided with anti-slip protrusions.

3. A combined spatial arch rib structure of inclined arch and curved beam according to claim 2, characterized in that, The welded studs are distributed in a matrix, the stiffening diaphragms are arranged at intervals along the longitudinal direction of the arch ribs, and the welded studs and stiffening diaphragms are arranged in the same plane.

4. The method for designing a combined spatial arch rib of a sloping arch curved beam according to claim 1, characterized in that, The outer wall of the steel structure arch rib is wrapped with a high-performance concrete layer with a thickness of 80-120mm.

5. The method for designing a combined spatial arch rib of a sloping arch curved beam according to claim 4, characterized in that, In step S4, the concrete pouring adopts a segmented pouring process, with the pouring sequence proceeding from the arch foot to the arch top, and the filling density is monitored in real time.

6. The method for designing a combined spatial arch rib of a sloping arch curved beam according to claim 5, characterized in that, It also includes step S5: After construction is completed, the arch rib strain and pile foundation displacement are monitored by fiber optic sensors. If the data exceeds the limit, micro-expansion concrete is poured in the corresponding zone.

Images