Design method for standard beam column type bridge bailey supports arranged in staggered layers

Abstract

The invention relates to the technical field of bridge construction, and discloses a design method of a standard beam column type bridge bailey support arranged in a staggered layer mode. The system comprises multiple layers of standard bailey trusses which are vertically arranged in a staggered mode, vertical rods correspond to pier bearing platforms or steel pipe piles close to the sides of the piers, a staggered area is formed in the midspan, and an upper support and a formwork are erected through bailey truss cantilevers; the construction sequentially comprises the steps of arranging steel pipe piles, layering a babley frame, installing a distribution beam and a support, building an upper support, checking and adjusting. The method follows the principle of no customization, no welding and no interruption, is adaptive to the scenes of oblique crossing bridges (capable of reaching 35 degrees), widening sections and the like, the component reuse rate is larger than or equal to 95%, the single-span construction period is shortened to 6-8 days, the cost is greatly reduced, and the problems that a traditional scheme is poor in economical efficiency, poor in adaptability and the like are solved.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, specifically to a design method for a staggered Bailey bridge support system for standard beam-column bridges. Background Technology

[0002] Current engineering practices, including existing patents, address the misalignment of Bailey bridge support points and their drawbacks:

[0003] 1. Custom-made non-standard Bailey bridges

[0004] Customized Bailey bridges with shortened or extended lengths (such as non-standard lengths like 2.4m or 3.6m) are made according to the bridge span.

[0005] Defects: Customization rate for single projects is as high as 40%, and turnover utilization rate is less than 20%; processing cycle is extended by 15-25 days.

[0006] 2. Filling the gap with cantilever support on the pier top

[0007] Weld a cantilever steel beam at the pier cap location, extending it to the standard vertical column position.

[0008] Defects: Difficulty in controlling the deflection at the cantilever end (must be limited to ≤L / 400); welding operations affect the durability of the bearing platform.

[0009] 3. Strengthen the vertical supports.

[0010] The suspended vertical pole area is reinforced with double channel steel wrapping or gusset plates.

[0011] Defects: Stress concentration at joints reduces fatigue life by 30%; increases steel consumption by 1.2-1.8 tons per span.

[0012] 4. Diagonal bracing auxiliary support system

[0013] Adding inclined steel pipes at 45°~60° will transfer the load to nearby support points.

[0014] Defects: The diagonal bracing occupies the clearance under the bridge (reducing the passage height by at least 2 meters); the foundation requires additional treatment.

[0015] 5. Adjustable hydraulic bracket

[0016] Hydraulic jacks are used to adjust the support height to match the position of the vertical rod.

[0017] Disadvantages: Equipment rental costs average 500-800 yuan per day; long-term operation carries the risk of oil seal leakage.

[0018] Summary of industry pain points:

[0019] Economic considerations: Non-standard components increase construction costs by 35%-50%.

[0020] Adaptability: For every 1m increase in width of the variable-width section, the connection nodes need to be redesigned.

[0021] Construction period: The average delay for skew bridges (>15°) is 28 days. Summary of the Invention

[0022] The purpose of this invention is to provide a design method for Bailey bridge supports with staggered arrangement of standard beams and columns, so as to solve the problems mentioned in the background art.

[0023] To achieve the above objectives, the present invention provides the following technical solution: a staggered Bailey bridge cast-in-place support system, comprising multiple layers of standard Bailey bridges arranged staggered in the height direction, wherein the vertical members of each layer of Bailey bridges are arranged from the permanent pier abutment or the steel pipe piles near the pier, forming a spatial staggered arrangement in the mid-span area, and the staggered area is provided by an upper support and cast-in-place formwork system erected on the cantilever of each layer of Bailey bridges.

[0024] Preferably, the distance between each layer of Bailey bridge in the height direction is equal to the height of one Bailey bridge plus the operating and deformation space.

[0025] Preferably, in front of the staggered area, distribution beams are set at the positions of the vertical poles of each layer of Bailey scaffold, and supports are set below the distribution beams according to the actual spacing.

[0026] Preferably, the spacing between the staggered areas is less than the allowable cantilever length under the stress conditions of the Bailey bridge.

[0027] Preferably, the upper support system may include, but is not limited to, disc-lock scaffolding and cast-in-place formwork systems.

[0028] Preferably, the standard Bailey bridge includes, but is not limited to, general models such as type 321, reinforced type, and type 200.

[0029] Based on the above system, the present invention also provides a construction method, as follows:

[0030] S1: Install steel pipe piles at both ends of the support frame on the permanent bridge abutment;

[0031] S2: Standard Bailey bridges are arranged in staggered layers according to the design elevation, so that the vertical members of each layer of Bailey bridges correspond to the pier cap or the steel pipe piles near the pier.

[0032] S3: Set up a distribution beam at the position of the Bailey bridge vertical pole in front of the staggered area, and set up steel pipe pile support below the distribution beam;

[0033] S4: In the staggered areas, a disc-lock scaffold and a cast-in-place formwork system are erected on the cantilever of each layer of Bailey bridge;

[0034] S5: Inspect and adjust the support system to ensure it meets the construction load requirements.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. Significantly improved economic efficiency: The entire structure adopts general standard Bailey bridges such as the 321 and 200 types, eliminating the need for customized non-standard components. The component reuse rate is increased from ≤80% in traditional solutions to ≥95%, directly reducing construction costs by 35%-50% and avoiding the drawbacks of low turnover and high investment of non-standard components.

[0037] 2. Significantly enhanced adaptability: It can flexibly cope with complex scenarios such as skew bridges and variable-width sections. Variable-width sections do not require customized irregular parts. They can be adapted simply by adjusting the number of support layers, completely solving the pain point of traditional solutions where nodes need to be redesigned for every 1m increase in the width of the variable-width section. Attached Figure Description

[0038] Figure 1 A schematic diagram illustrating the adjustment of the central area using a non-standard Bailey bridge;

[0039] Figure 2 This is a schematic diagram of the arrangement of a standard Bailey bridge with two layers.

[0040] Figure 3 This is a schematic diagram of the intersecting area of ​​two standard Bailey beams on the upper and lower levels.

[0041] Figure 4 This is a design schematic diagram showing the Bailey bridge vertical members starting from the permanent pier cap;

[0042] Figure 5 This is a design schematic diagram showing the Bailey bridge vertical members starting from the steel pipe pile position near the pier.

[0043] Figure 6 yes Figure 2 Diagram showing the central location.

[0044] In the diagram: 1. Pier; 101. Pier attachment; 2. Steel pipe pile; 201. Steel pipe pile support; 3. Bailey beam; 301. Bailey beam chord; 302. Bailey beam vertical member; 303. Bailey beam end column; 304. Bailey beam diagonal member; 4. Distribution beam; 5. Disc-lock bracket; 6. Beam body. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] The core innovation of this invention: Achieving the "three no's" principle through vertically staggered arrangement of standard Bailey bridges—

[0047] 1. No customization: All use standard Bailey bridges of type 321 or 200 (length 3m / 2m, height 1.5m).

[0048] 2. No welding: All joints are connected by pins / bolts.

[0049] 3. Uninterrupted: The load transfer path is continuous and without abrupt changes.

[0050] Specific technical solution:

[0051] Step 1: Based on the bridge span and load design, determine the number of support layers (usually 2 layers) and the staggered layer height (Bailey height + operating space).

[0052] Step 2: Arrange the first layer of Bailey bridge at the abutment and pier locations, with the vertical members aligned with the support points; the cantilever length at mid-span should be less than or equal to the allowable cantilever length under stress.

[0053] Step 3: The second layer of Bailey bridge is vertically staggered, with its vertical members aligned with the support points on the other side, and the load is transferred to the lower cantilever through the distribution beam at the mid-span.

[0054] Step 4: In the staggered area, a disc-lock scaffold is erected on the Bailey bridge cantilever to support the cast-in-place formwork and construction loads (or other construction components and equipment).

[0055] Step 5: After verifying the overall stability, pour concrete (or carry out other support construction work). When dismantling, operate in reverse layer by layer, and recycle the components by category.

[0056] Technical effect comparison:

[0057] index Traditional solution This invention Component reuse rate ≤80% ≥95% Oblique adaptability Maximum 10° Up to 35° Construction of widened section Custom-made irregular parts required Simply adjust the number of layers. Single span of construction period 10-12 days 6-8 days

[0058] The following specific examples will provide further insight.

[0059] Example 1

[0060] The third Bailey bridge span is arranged in a 26m span cast-in-place continuous box girder.

[0061] In this cast-in-place box girder design, the Bailey bridge arrangement needs to be adjusted at the ends using a non-standard Bailey bridge stage to better match the span. For example... Figure 1 As shown, the starting point uses a 3m long standard Bailey bridge, and the ending point is adjusted using a 2m non-standard Bailey bridge based on the remaining space. The component reuse rate is low.

[0062] A tiered Bailey bridge design is used to address the fragmented layout issues in the project. This avoids the large-scale use of non-standard Bailey bridges, such as... Figure 2As shown, by arranging the upper and lower layers of Bailey bridges, standard 3m long Bailey bridges can be used for each layer. The stress mode of each Bailey bridge is a simply supported short cantilever structure, resulting in smooth force transmission. The component reuse rate is high.

[0063] At the same time, in terms of adapting to flat curves, such as Figure 3 As shown, by adjusting the spacing between two adjacent supports, it can better adapt to changes in road curves, demonstrating strong adaptability.

[0064] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A staggered Bailey bridge cast-in-place support system, characterized in that, It includes multiple layers of standard Bailey bridges arranged in a staggered manner in the height direction. The vertical members of each layer of Bailey bridges are arranged from the permanent pier abutment or the steel pipe piles near the pier side. The mid-span area forms a spatial staggered arrangement. The staggered area is supported by the upper support and cast-in-place formwork system erected on the cantilever of each layer of Bailey bridges.

2. The staggered Bailey bridge cast-in-place support system according to claim 1, characterized in that, The distance between each layer of Bailey bridge in the vertical direction is equal to the height of one Bailey bridge plus the operating and deformation space.

3. The staggered Bailey bridge cast-in-place support system according to claim 1, characterized in that, Before the staggered area, distribution beams are set at the positions of the vertical poles of each layer of Bailey bridge, and supports are set below the distribution beams according to the actual spacing.

4. The staggered Bailey bridge cast-in-place support system according to claim 1, characterized in that, The spacing between the staggered zones is less than the allowable cantilever length under the stress conditions of the Bailey bridge.

5. The staggered Bailey bridge cast-in-place support system according to claim 1, characterized in that, The upper support system may include, but is not limited to, disc-lock scaffolding and cast-in-place formwork systems.

6. The method according to claim 1, characterized in that, The standard Bailey bridge includes, but is not limited to, general models such as type 321, reinforced type, and type 200.

7. A construction method for a staggered Bailey bridge cast-in-place support system as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Install steel pipe piles at both ends of the support frame on the permanent bridge abutment; S2: Standard Bailey bridges are arranged in staggered layers according to the design elevation, so that the vertical members of each layer of Bailey bridges correspond to the pier cap or the steel pipe piles near the pier. S3: Set up a distribution beam at the position of the Bailey bridge vertical pole in front of the staggered area, and set up steel pipe pile support below the distribution beam; S4: In the staggered areas, a disc-lock scaffold and a cast-in-place formwork system are erected on the cantilever of each layer of Bailey bridge; S5: Inspect and adjust the support system to ensure it meets the construction load requirements.

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