Ground anchor auxiliary beam curved bridge and its construction method

Abstract

The present invention discloses a ground anchor assisted beam curved bridge and its construction method, which includes an upper curved continuous beam. At both ends of the upper curved continuous beam, abutments, ground anchors and middle piers of the lower structure are successively arranged from outside to inside; the arrangement of each ground anchor includes a rigid swing column, a ground anchor cap and a ground anchor pile connected successively from top to bottom; the rigid swing columns and the ground anchor piles of each ground anchor are arranged in pairs on both sides of the corresponding bridge structure center line; between the upper end of each rigid swing column and the upper curved continuous beam, and between the lower end and the corresponding ground anchor cap, they are connected by a rotatable relative connecting piece including a pin shaft. During construction, a support is erected and a jack is set, and then the upper curved continuous beam is installed in segments; the load of the upper curved continuous beam is transferred to each ground anchor by gradually unloading the jack. The present invention realizes the structural functions of large span and low beam height that can only be achieved by traditional complex bridge types with a simpler structure.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and particularly to a ground anchor assisted beam curved bridge and its construction method. Background Art

[0002] In bridge engineering, the problem of limited beam height is often encountered, which brings great difficulties to bridge design. The conventional method to reduce the beam height of the upper part of a long-span bridge is to adopt complex bridge type schemes, such as truss bridges, through arch bridges, cable-stayed bridges, cable-assisted beam bridges or suspension bridges. These schemes all need to set bridge towers, arches or truss structures above the bridge deck.

[0003] When the boundary conditions do not allow the setting of structures on the bridge deck, the above-mentioned schemes cannot meet the requirements.

[0004] Curved bridges are widely used in modern bridges. Due to the influence of the plane curvature radius, the bending and torsion coupling effect of curved bridges makes their structural stress and stability more complex than that of straight beam bridges.

[0005] The conventional design method for curved bridges to improve stability is to optimize the stability performance of curved bridges by adjusting the curvature radius, support spacing and support type.

[0006] For long-span, low-beam-height curved flexible beam bridges, the above methods have limited effect on the stability of the bridges and cannot meet the stability requirements.

[0007] Therefore, how to meet the bridge stability of long-span, low-beam-height curved flexible beam bridges has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0008] In view of the above-mentioned defects of the prior art, the present invention provides a ground anchor assisted beam curved bridge and its construction method, and the achieved purpose is to solve the problem that it is difficult for curved flexible beam bridges with limited beam height caused by complex boundary conditions and special requirements to meet stability. Without the need to arrange bridge towers, arches or truss structures on the bridge deck, the stability requirements of long-span, low-beam-height flexible beam bridges can be met.

[0009] To achieve the above purpose, the present invention discloses a ground anchor assisted beam curved bridge, which includes an upper curved continuous beam. At both ends of the upper curved continuous beam, from outside to inside, there are successively abutments, ground anchors and intermediate piers of the lower structure;

[0010] Each of the abutments and each of the intermediate piers of the lower structure are connected to the upper curved continuous beam through bearings;

[0011] Each of the ground anchors is arranged at a position near the mid-span of the side span of the upper curved continuous beam, and the upper end is connected to the upper curved continuous beam through a pin shaft. Each ground anchor includes a rigid swing column, a ground anchor cap and a ground anchor pile which are connected successively from top to bottom;

[0012] The rigid swing columns and the ground anchor piles of each of the ground anchors are arranged in pairs on both sides of the corresponding bridge structure center line;

[0013] Between the upper end of each of the rigid swing columns and the upper curved continuous beam, and between the lower end and the corresponding ground anchor cap, they are connected by a rotatable connection member including a pin shaft.

[0014] Preferably, the center line of the upper curved continuous beam structure is a circular curve, a transition curve, or a combined linear shape of a circular curve, a transition curve and a straight line.

[0015] Preferably, each of the rotatable connection members includes the corresponding pin shaft, spherical plain bearing, inner ear plate and outer ear plate;

[0016] The outer ear plate of each of the rotatable connection members is connected to the corresponding upper curved continuous beam or the corresponding ground anchor cap;

[0017] Each of the outer ear plates is provided with the corresponding inner ear plate, there is a gap between them, and they are connected by the corresponding spherical plain bearing.

[0018] More preferably, the upper curved continuous beam and each of the outer ear plates are connected by welding; each of the ground anchor caps and the corresponding outer ear plates are connected by welding.

[0019] Preferably, at the position where each of the ground anchor caps is connected to the corresponding outer ear plate, an anchor pile cap embedded steel plate is provided;

[0020] Each of the anchor pile cap embedded steel plates is fixed to a number of screw rods embedded in the corresponding ground anchor cap by bolts, and during installation, the height can be adjusted by adjusting the fastening position of the corresponding bolts on the corresponding screw rods.

[0021] The present invention also provides a construction method for a ground anchor auxiliary beam curved bridge, including the following three stages:

[0022] The first stage: After erecting the support and setting the jacks, the upper curved continuous beam is installed in segments and assembled into a whole on the support;

[0023] The second stage: Remove the support in the side span range corresponding to the upper curved continuous beam, only retain the support in the main span corresponding to the upper curved continuous beam, and then install the rigid swing columns, and make all the rigid swing columns in a non-loaded state;

[0024] In the third stage, adjust the installation height of the embedded steel plates of each anchor pile cap on the ground anchor cap, remove the supports corresponding to the main span of the upper curved continuous beam, and transfer the load of the upper curved continuous beam to the ground anchor, the middle pier of the lower structure and the abutment by gradually unloading the jacks, so that among each pair of rigid swing columns, the rigid swing column farther from the center of curvature corresponding to the upper curved continuous beam bears pressure, and the rigid swing column closer to the center of curvature corresponding to the upper curved continuous beam bears tension.

[0025] Advantages of the present invention:

[0026] The present invention realizes the structural functions of large span and low beam height that can only be achieved by traditional complex bridge types with a more concise structure, realizes the lightening of large-span bridges, realizes the span improvement of flexible beam bridges, and the project cost is equivalent to that of traditional beam bridges and far lower than that of traditional complex bridge types, with significant economic benefits, providing a new solution for flexible beam bridges with height restrictions.

[0027] The paired ground anchors in the present invention improve the bending and torsion resistance of the new structural system, making the flexible beam bridge with a small height-span ratio of the upper curved beam and unable to meet the actual span relying on the strength and stiffness of the curved beam itself meet the requirements.

[0028] In the present invention, the connection between the rigid swing column, the ground anchor pile and the upper curved beam adopts a bidirectional horizontal displacement pin shaft structure, which releases the secondary internal force under the action of temperature effect and live load and improves the structural safety.

[0029] In the present invention, according to the stress state of the structural system, it is divided into three construction stages, all of which adopt traditional processes, with mature processes and convenient construction.

[0030] Compared with the prior art, the present invention reduces the height-span ratio of the curved beam, making the bridge structure light and beautiful in shape.

[0031] The following will further illustrate the concept, specific structure and technical effects generated by the present invention with reference to the drawings, so as to fully understand the purpose, features and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Shows a plan view of the upper curved continuous beam in an embodiment of the present invention.

[0033] Figure 2 Shows a side structural schematic diagram of the connection structure of the upper curved continuous beam, the abutment, the ground anchor and the middle pier of the lower structure in an embodiment of the present invention.

[0034] Figure 3 Shows a structural schematic diagram of the cross section of the bridge corresponding to the ground anchor in an embodiment of the present invention.

[0035] Figure 4 Schematic structural diagram of the ground anchor corresponding to the longitudinal section of the bridge in an embodiment of the present invention.

[0036] Figure 5 Schematic structural diagram of the connection between the rigid sway column and the upper curved continuous beam in an embodiment of the present invention.

[0037] Figure 6 Schematic structural diagram of the connection between the rigid sway column and the ground anchor cap in an embodiment of the present invention. Detailed implementation manners

[0038] Embodiment

[0039] As Figures 1 to 6 shown, the ground anchor assisted beam curved bridge includes an upper curved continuous beam 1. At both ends of the upper curved continuous beam 1, abutments 4, ground anchors 2, and intermediate piers 3 in the lower structure are successively arranged from outside to inside;

[0040] Each abutment 4 and each intermediate pier 3 in the lower structure are connected to the upper curved continuous beam 1 through bearings;

[0041] Each ground anchor 2 is arranged at a position near the mid-span of the side span of the upper curved continuous beam 1, and the upper end is connected to the upper curved continuous beam 1 through a pin shaft 8, and each includes a rigid sway column 5, a ground anchor cap 6, and a ground anchor pile 7 that are successively connected from top to bottom;

[0042] The rigid sway columns 5 and the ground anchor piles 7 of each ground anchor 2 are arranged in pairs on both sides of the corresponding bridge structure center line;

[0043] Between the upper end of each rigid sway column 5 and the upper curved continuous beam 1, and between the lower end and the corresponding ground anchor cap 6, they are connected through a rotatable connecting member including a pin shaft 8.

[0044] The principle of the present invention is as follows:

[0045] The present invention connects the ground anchor 2 with the side span of the upper curved continuous beam 1 to form a structural system in which the curved continuous beam and the ground anchor 2 jointly bear the load.

[0046] The present invention takes the upper curved continuous beam 1 as the main load-bearing body, and the ground anchor 2 that provides vertical tensile and compressive forces for the upper curved continuous beam 1 is the auxiliary load-bearing body.

[0047] The ground anchor 2 of the present invention is arranged at a position near the mid-span of the side span of the upper curved continuous beam 1. According to the theory of structural line stiffness and influence line, under the action of vertical load, the positive moment at the mid-span of the main span and the torque at the mid-support can be greatly reduced, and the deflection of the main span and the torsional angle of the mid-support can be greatly reduced.

[0048] The ground anchor 2 of the present invention provides appropriate tensile and compressive forces for the upper curved continuous beam 1, achieving a significant reduction in the height-span ratio of the upper curved continuous beam 1 to meet the requirements of specific environments and span lengths.

[0049] The ground anchor 2 of the present invention is designed according to an appropriate load-bearing ratio, with the upper curved continuous beam 1 as the main load-bearing member and the ground anchor 2 as the secondary load-bearing member. Through the optimized design of the load-bearing ratio, the optimal force-bearing state of the upper curved continuous beam 1 and the ground anchor 2 is achieved.

[0050] The ground anchor 2 of the present invention includes paired rigid swing columns 5 and ground anchor piles 7, which are arranged on both sides of the center line of the bridge structure. Between the upper end of each rigid swing column 5 and the upper curved continuous beam 1, and between the lower end and the corresponding ground anchor cap 6, they are connected by a rotatable connection member including a pin shaft 8. Through the rotation of the spherical plain bearing of the rotatable connection member and the clearance reserved by the ear plate, the two-way horizontal displacement of the upper curved continuous beam 1 in the longitudinal and transverse directions of the bridge can be realized.

[0051] The ground anchor of the present invention adopts an integrated tension and compression design. The rigid swing columns 5 and the ground anchor piles 7 can bear both large compressive forces and large tensile forces.

[0052] In some embodiments, the center line 12 of the upper curved continuous beam 1 is a circular curve, a transition curve, or a combined linear shape of a circular curve and a transition curve with a straight line.

[0053] In some embodiments, each rotatable connection member includes a corresponding pin shaft 8, a spherical plain bearing 9, an inner ear plate 10, and an outer ear plate 11;

[0054] The outer ear plate 11 of each rotatable connection member is connected to the corresponding upper curved continuous beam 1 or the corresponding ground anchor cap 6;

[0055] Each outer ear plate 11 is provided with a corresponding inner ear plate 10, there is a clearance between them, and they are connected by a corresponding spherical plain bearing 9.

[0056] In practical applications, the existing spherical plain bearings are divided into two parts, the lower part can rotate, and the upper part can both rotate and horizontally displace. The outer ear plate 11 and the inner ear plate 10 connected to the upper curved beam achieve horizontal displacement by relying on the rotation of the lower part and the rotation of the upper part of the spherical plain bearing.

[0057] In some embodiments, the upper curved continuous beam 1 and each outer ear plate 11 are connected by welding; each ground anchor cap 6 and the corresponding outer ear plate 11 are connected by welding.

[0058] In some embodiments, an anchor pile cap embedded steel plate 13 is provided at the position where each ground anchor cap 6 is connected to the corresponding outer ear plate 11;

[0059] Each embedded steel plate 13 of the anchor pile cap is fixed to several screw rods embedded in the corresponding ground anchor cap 6 by bolts. During installation, the height can be adjusted by adjusting the fastening position of the corresponding bolt on the corresponding screw rod.

[0060] In practical applications, the height of the embedded steel plate 13 of the anchor pile cap is adjustable, and the installation height of the embedded steel plate can be adjusted, that is, the tension and pressure on the corresponding rigid swing column 5 can be adjusted, so that the rigid swing column 5 reaches the load-bearing ratio required by the design, and the optimal force between the rigid swing column 5 and the upper curved continuous beam 1 is achieved.

[0061] The present invention also provides a construction method for a ground anchor auxiliary beam curved bridge, including the following three stages:

[0062] The first stage: After erecting the support and setting the jacks, the upper curved continuous beam 1 is installed in segments and assembled into a whole on the support;

[0063] The second stage: Remove the support in the side span range of the corresponding upper curved continuous beam 1, only retain the support of the main span of the corresponding upper curved continuous beam 1, and then install the rigid swing column 5, and make all the rigid swing columns 5 in a state of not being stressed;

[0064] The third stage: Adjust the installation height of the embedded steel plate 13 of the anchor pile cap on each ground anchor cap 6, remove the support of the main span of the corresponding upper curved continuous beam 1, and adopt the method of gradually unloading the jacks to transfer the load of the upper curved continuous beam 1 to the ground anchor 2, the middle pier 3 and the abutment 4 of the lower structure, so that among each pair of rigid swing columns 5, the rigid swing column 5 with a longer distance from the center of curvature of the corresponding position of the upper curved continuous beam 1 bears pressure, and the rigid swing column 5 with a shorter distance from the center of curvature of the corresponding position of the upper curved continuous beam 1 bears tension.

[0065] In practical applications, since the deflection of the upper curved continuous beam 1 as a flexible beam is relatively large during the removal of the formwork, the system conversion is completed by gradually unloading the jacks to form a ground anchor auxiliary beam curved bridge.

[0066] According to the theory of structural line stiffness and influence line, the advantage of the present invention is to give full play to the load-bearing function of the ground anchor 2 to assist the upper curved continuous beam 1, and the positive bending moment in the middle of the main span and the torque at the middle support can be greatly reduced, and the deflection of the main span and the torsional angle at the middle support can also be greatly reduced.

[0067] The present invention makes the flexible beam bridge with a relatively small height-span ratio of the upper curved continuous beam 1 and unable to meet the actual span relying on its own strength and stiffness meet the requirements.

[0068] The structural system of the present invention reduces the height-span ratio of the curved beam, which is manifested in the overall layout as:

[0069] 1. Under the same load and cross-section conditions, the bridge span can be increased;

[0070] 2. Under the same load and span conditions, the height of the bridge cross-section can be reduced;

[0071] 3. Or a combination of the first two solutions, that is, under the same load condition, both the span increase and the beam height reduction are achieved.

[0072] The present invention adopts a novel structure to achieve the lightening of the bridge, enabling the bridge structure to be more lightweight and the shape to be more beautiful.

[0073] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. Ground anchor assisted beam curved bridge, including an upper curved continuous beam (1); characterized in that, Both ends of the upper curved continuous beam (1) are provided with abutments (4), ground anchors (2) and lower structure middle piers (3) in sequence from outside to inside; Each of the abutments (4) and each of the lower structure piers (3) are connected to the upper curved continuous beam (1) via a support; Each of the ground anchors (2) is arranged at a side span of the upper curved continuous beam (1) near the mid-span position, and the upper end is connected to the upper curved continuous beam (1) via a pin (8), and each includes a rigid rocking column (5), a ground anchor cap (6), and a ground anchor pile (7) connected in sequence from top to bottom; The rigid rocking column (5) and the anchor pile (7) of each ground anchor (2) are arranged in pairs on both sides of the center line of the corresponding bridge structure; The upper end of each rigid rocking column (5) and the upper curved continuous beam (1), as well as the lower end and the corresponding anchor cap (6), are connected via relatively rotatable connecting members including a pin shaft (8); The structural center line (12) of the upper curved continuous beam (1) is a circular curve, a transition curve, or a combination of a circular curve, a transition curve and a straight line; Each of the relatively rotatable connecting members comprises a corresponding pin shaft (8), a joint bearing (9), an inner ear plate (10) and an outer ear plate (11); The outer ear plate (11) of each relatively rotatable connecting member is connected to the corresponding upper curved continuous beam (1) or the corresponding anchor cap (6); Each of the outer ear plates (11) is provided with a corresponding inner ear plate (10), a gap exists between the corresponding inner ear plate (10), and the outer ear plates (11) are connected via the corresponding joint bearing (9); The upper curved continuous beam (1) and each of the outer ear plates (11) are connected by welding; each of the anchor caps (6) and the corresponding outer ear plates (11) are connected by welding; A position on each of the ground anchor caps (6) connected to the corresponding outer ear plate (11) is provided with an anchor cap pre-buried steel plate (13); Each anchor pile cap embedded steel plate (13) is fixed to a plurality of screw rods embedded in the corresponding anchor cap (6) by bolts. During installation, the height can be adjusted by adjusting the fastening position of the corresponding bolts on the corresponding screw rods.

2. The construction method of the ground anchor assisted beam curved bridge according to claim 1, characterized in that It includes the following three stages: In the first stage, after erecting the support and setting the jack, the upper curved continuous beam (1) is installed in sections and assembled into a whole on the support; In the second stage, the brackets corresponding to the side span of the upper curved continuous beam (1) are removed, and only the brackets corresponding to the main span of the upper curved continuous beam (1) are retained, and then the rigid swing columns (5) are installed, and all the rigid swing columns (5) are placed in a state of being free of stress; In the third stage, adjust the installation height of the embedded steel plates (13) of the anchor pile caps on each of the ground anchor caps (6), remove the supports for the main span of the upper curved continuous beam (1), and transfer the load of the upper curved continuous beam (1) to the ground anchors (2), the intermediate piers (3) of the lower structure, and the abutments (4) by gradually unloading the jacks, so that among each pair of the rigid swing columns (5), the rigid swing column (5) with a longer distance from the center of curvature at the corresponding position of the upper curved continuous beam (1) bears compression, and the rigid swing column (5) with a shorter distance from the center of curvature at the corresponding position of the upper curved continuous beam (1) bears tension.

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