Beam-arch combined system arch bridge self-adaptive to suspender force

Abstract

The utility model discloses a beam-arch combined system arch bridge self-adaptive to suspender force, which comprises a main beam at the lower part of a bridge deck, the main beam is a combined structure in which a main longitudinal beam, a secondary longitudinal beam and a cross beam are jointly stressed, the main longitudinal beam is of a box-shaped structure and is arranged on two sides of the cross beam, and a web plate of the cross beam is fixedly connected with the main longitudinal beam. The secondary longitudinal beams are generally and fixedly arranged on the two sides of the middle of the bottom face of the cross beam in the bridge direction, lower arch ribs and upper arch ribs are symmetrically arranged between the two sides of the main beam, truss web members are continuously and fixedly arranged between the lower arch ribs and the upper arch ribs, and the symmetrical lower arch ribs and the symmetrical upper arch ribs are fixedly connected through arch rib cross braces; and vertical suspenders are uniformly distributed between the lower arch rib and the main beam. The utility model aims to provide the beam-arch combined system arch bridge which does not need secondary adjustment of suspender force and is self-adaptive to the suspender force.

Description

Technical Field

[0001] This utility model relates to the field of bridge construction technology, and in particular to an arch bridge with an adaptive suspender force beam-arch composite system. Background Technology

[0002] The beam-arch composite system arch bridge is a thrustless system with a simply supported external structure and a highly statically indeterminate internal structure. The magnitude of the suspender force has a significant impact on the bridge alignment and structural stress of the beam-arch composite system arch bridge. Each set of suspender forces corresponds to a bridge completion state. Therefore, in the design and construction process, determining the appropriate suspender force corresponding to a reasonable bridge completion state and achieving the appropriate suspender force during construction is a key issue in the design and construction control of this type of structure.

[0003] Currently, there are various methods for determining the reasonable suspender force during the design phase of arch bridges with beam-arch composite systems, such as the rigidly supported continuous beam method, the zero-displacement method, the internal balance method, the rigid suspender method, the minimum bending energy method, the minimum bending moment method, and the constrained minimum bending energy method. However, since the construction of arch bridges is completed in multiple stages, the suspender force changes at each stage. Without human control, it is extremely difficult to achieve the reasonable suspender force at the completed bridge stage. Usually, the suspender force at the completed bridge stage will differ significantly from the reasonable suspender force provided in the design. Therefore, secondary adjustments to the suspender force are usually required after the bridge is completed. Because arch bridges with beam-arch composite systems are highly statically indeterminate structures, any change in the suspender force will affect the forces of the remaining suspenders. Therefore, secondary adjustments to the suspender force often need to be repeated multiple times, making the process cumbersome and difficult to control. Therefore, there is an urgent need for an arch bridge with a beam-arch composite system that does not require secondary adjustments to the suspender force and is self-adaptive to the suspender force. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to provide an arch bridge with a beam-arch combination system that does not require secondary adjustment of the suspender force and is self-adaptive to the suspender force.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0006] An adaptive hanger force beam-arch bridge system includes a main beam under the bridge deck. The main beam is a composite structure consisting of a main longitudinal beam, secondary longitudinal beams, and cross beams that share the load. The main longitudinal beams are box-shaped structures set on both sides of the cross beams. The webs of the cross beams are fixedly connected to the main longitudinal beams. The secondary longitudinal beams are typically fixedly set on both sides of the bottom center of the cross beams along the bridge direction. Lower arch ribs and upper arch ribs are symmetrically arranged between both sides of the main beam. Truss web members are continuously fixedly arranged between the lower arch ribs and the upper arch ribs. The symmetrical lower arch ribs and the symmetrical upper arch ribs are fixedly connected by arch rib cross braces. Vertical hangers are evenly distributed between the lower arch ribs and the main beam.

[0007] Furthermore, the secondary longitudinal beam has an I-shaped cross-section.

[0008] Furthermore, the bridge deck is a steel-concrete composite beam bridge deck, and the steel beams inside the bridge deck are provided with longitudinal U-shaped stiffening ribs.

[0009] Furthermore, the suspension rod is made of PES7-85 parallel steel wire, and the end of the suspension rod is connected to the lower arch rib and the main beam through a fork lug.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] This invention adjusts the shape and component dimensions of the arch ribs and main beams to ensure that the stiffness ratio of the arch ribs and main beams is within a specific range. When external loads are applied to the main beams, the relative displacements at the upper and lower ends of the different hangers caused by the external loads are not significantly different. This ensures that the force of each hanger is relatively uniform, eliminating the need for secondary adjustments to the hanger forces during the bridge completion stage. The biggest advantage of this structure is that it avoids repeated adjustments due to uneven hanger forces during construction, facilitating construction, shortening the construction period, and simplifying on-site construction quality control. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model;

[0013] Figure 2 This is a top view of the present invention;

[0014] Figure 3 This is a schematic diagram of the main beam in this utility model.

[0015] Figure label:

[0016] 1-Lower arch rib, 2-Upper arch rib, 3-Truss web member, 4-Main beam, 5-Arch rib cross brace, 6-Bridge deck, 7-Hanger rod, 41-Main longitudinal beam, 42-Secondary longitudinal beam, 43-Cross beam. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] like Figures 1 to 3As shown, an adaptive suspender force beam-arch composite system arch bridge includes a main beam 4 under the bridge deck 6. The main beam 4 is a composite structure with main longitudinal beams 41, secondary longitudinal beams 42, and cross beams 43 sharing the load. The main longitudinal beams 41 are box-shaped structures set on both sides of the cross beams 43. The web of the cross beams 43 is fixedly connected to the main longitudinal beams 41. The secondary longitudinal beams 42 are usually fixedly set on both sides of the bottom center of the cross beams 43 along the bridge direction. Lower arch ribs 1 and upper arch ribs 2 are symmetrically arranged between both sides of the main beam 4. Truss web members 3 are continuously fixedly arranged between the lower arch ribs 1 and the upper arch ribs 2. The symmetrical lower arch ribs 1 and the symmetrical upper arch ribs 2 are fixedly connected by arch rib cross braces 5. Vertical suspenders 7 are evenly distributed between the lower arch ribs 1 and the main beam 4.

[0019] In this embodiment, the upper arch rib 2 has a span of approximately 150m and a rise of 23.5m; the lower arch rib 1 has a span of approximately 106m and a rise of 20m; the truss web member 3 has a net rise of 19.4m; the rise-span ratio is 1:5.5; and the height difference between the tops of the upper and lower arch ribs is 3.5m.

[0020] The main longitudinal beam 41 has a box girder cross-section, with a center-to-center distance of 27m between the two main beams in the transverse direction. The top plate thickness is 20mm, the bottom plate thickness is 20mm, and the web thickness is 20mm, with a web spacing of 1.5m or 1.2m. The standard length of main beam 41 is 6m, and the beam height is 2.4m. The beam segments are welded together to form a whole. The secondary longitudinal beam 42 has an I-beam cross-section, with a bottom plate width of 400mm, a web thickness of 16mm, and a beam height of 1.6m. To ensure lateral stability and uniform stress distribution in the upper compression zone of cross beam 43, it is installed along the entire length of the bridge on both sides of the middle section of cross beam 43. Cross beam 43 has an I-beam cross-section, a standard length of 22.8m, a standard spacing of 3m, a bottom plate width of 400mm, a web thickness of 16mm, a beam height of 2.4m at the ends, and a beam height of 2.57m in the middle. The web of the crossbeam 43 is welded to the main longitudinal beam 41 to form a whole. The crossbeam 43 at the side support and the middle support is a reinforced box section with a plate thickness of 20mm. The width of the crossbeam 43 at the side support is 1.5m, and the width of the crossbeam 43 at the middle support is 1.8m.

[0021] The bridge deck 6 is a steel-concrete composite beam bridge deck. The steel beams within the bridge deck are equipped with longitudinal U-shaped stiffening ribs. The bridge deck 6 is made of 14cm thick C50 steel fiber reinforced concrete, and the steel beams and concrete are connected by welded studs. The hangers 7 are made of PES7-85 parallel steel wire, and the ends of the hangers 7 are connected to the lower arch rib 1 and the main beam 4 through fork lugs. There are 15 hangers 7 at each arch rib, for a total of 30 hangers throughout the bridge, with a hanger spacing of 6m.

[0022] In this embodiment, the arch bridge is constructed using the incremental launching construction method.

[0023] (1) Construct two temporary support piers between the main piers, install the slide beam, install the vertical and horizontal jack adjustment devices and debug the jacking equipment.

[0024] (2) At the assembly site, the arch bridge steel box girder structure is assembled, the arch rib steel pipe, the hanger 7 and the guide beam are installed. After the hanger 7 is installed, a certain tension force is applied as required. At the same time, the pier jacking traction system and the correction system are installed and the jacking system is debugged and ready.

[0025] (3) Start the jacking system and jack forward. When the anchor is close to the pier, stop jacking and drag the bundle of steel strands to the next pier for installation, and continue jacking. When the next anchor is close to the pier, remove the steel strands on it, and then switch to the next anchor. After the switched steel strands are re-tightened, continue jacking.

[0026] (4) When the guide beam is pushed to the first main pier, the guide beam is removed, the beam system is converted, and the entire bridge is placed on the permanent support to complete the jacking construction.

[0027] (5) Remove the temporary supports and jacking equipment, lower the beam to the design elevation, and complete the jacking construction.

[0028] Generally, when external loads act on an arch bridge with a beam-arch composite system, both the main beam and the main arch deflect downwards, with the deformation gradually decreasing from the mid-span to both sides. The difference in deformation between the main beam and the main arch at a certain hanger can reflect the magnitude of the hanger force. Assuming the arch rib has high stiffness and almost no deformation, the hanger force is only related to the deformation of the main beam, which is obviously uneven. Similarly, assuming the main beam has high stiffness and almost no deformation, the hanger force is only related to the deformation of the arch rib, which is also uneven. In both cases, this unevenness can be reduced by adjusting the stiffness of the arch rib and the main beam to change the deformation. Imagine a bridge type where the relative stiffness of the arch rib and the main beam is within a specific range. When external loads act on the arch bridge, both the beam and the arch deform, but the difference in deformation between the main beam and the main arch at each hanger is not significant. In this case, the hanger force will become very uniform, and no secondary adjustment of the hanger force is needed during the bridge completion stage. This invention represents such a structure. Since the stress on an arch bridge is greatly related to the arch rib shape and the rise-to-span ratio, the specific range of relative stiffness of the arch beam is different for different arch rib shapes and rise-to-span ratios. This invention will be used as an example to illustrate the method for determining this specific range.

[0029] The arch rib of the arch bridge described in this utility model has a circular arc shape and a rise-to-span ratio of 1:5.5. The main beam has relatively high stiffness and belongs to the "rigid beam flexible arch" system. By changing the cross-sectional dimensions of the arch rib and the main beam, the relative bending stiffness of the two can be changed. With the arch rib stiffness / main beam stiffness as the independent variable, the results of the hanger force in the interval (0,1) are calculated as follows. The percentage difference between the maximum hanger force and the minimum hanger force and the difference between adjacent hangers are used as a measure of whether the hanger force is uniform.

[0030] Relative values ​​of suspender force under different stiffness ratios

[0031]

[0032] The table above shows that as the arch-beam stiffness ratio increases, the percentage difference between the maximum and minimum suspender forces first decreases and then increases, meaning the uniformity of the suspender forces first increases and then decreases. The uniformity of the suspenders is best within the range of [0.009, 0.01]. For the arch bridge described in this invention, designing the relative stiffness of the arch ribs and main beams within this range achieves the objective described in this invention.

[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An arch bridge with an adaptive suspender force beam-arch composite system, comprising a main beam (4) below the bridge deck (6), characterized in that: The main beam (4) is a combined structure in which the main longitudinal beam (41), secondary longitudinal beam (42), and cross beam (43) share the load. The main longitudinal beam (41) is a box-shaped structure set on both sides of the cross beam (43). The web of the cross beam (43) is fixedly connected to the main longitudinal beam (41). The secondary longitudinal beam (42) is usually fixedly set on both sides of the bottom center of the cross beam (43) along the bridge direction. The main beam (4) is symmetrically provided with lower arch ribs (1) and upper arch ribs (2) on both sides. The lower arch ribs (1) and upper arch ribs (2) are continuously fixedly provided with truss web members (3) between them. The symmetrical lower arch ribs (1) and the symmetrical upper arch ribs (2) are fixedly connected by arch rib cross braces (5). Vertical hangers (7) are evenly distributed between the lower arch ribs (1) and the main beam (4).

2. The beam-arch composite system arch bridge with adaptive suspender force according to claim 1, characterized in that: The secondary longitudinal beam (42) has an I-shaped cross section.

3. The beam-arch composite system arch bridge with adaptive suspender force according to claim 1, characterized in that: The bridge deck (6) is a steel-concrete composite beam bridge deck, and the steel beams inside the bridge deck (6) are provided with longitudinal U-shaped stiffening ribs.

4. The beam-arch composite system arch bridge with adaptive suspender force according to claim 1, characterized in that: The hanger (7) is made of PES7-85 parallel steel wire, and the end of the hanger (7) is connected to the lower arch rib (1) and the main beam (4) through a fork lug.

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