Bridge bent frame pier-straining beam joint with compressible bending steel plate

Abstract

The invention relates to the technical field of bridge engineering, and discloses a bridge bent frame pier-straining beam node with a compressible bending steel plate, which is arranged at the intersection of a pier column and a straining beam and comprises a weakening straining beam positioned at the straining beam towards the connecting end of the pier column, and the section height of the weakening straining beam is smaller than that of the straining beam; the compressible bending steel plate assemblies are located on the upper side and the lower side of the weakening straining beam, and the buckling-restrained cover plate assemblies correspondingly clamp the bending steel plate assemblies on the upper side and the lower side respectively. The two ends of the bent steel plate assemblies on the upper side and the lower side are fixedly connected with pier columns and straining beams correspondingly. The bent steel plate assembly has the characteristic of secondary yield when being pulled and pressed; the bent steel plate assembly has the advantages of being weak first and then strong and large in deformability, the bent frame pier can form a strong-column and weak-beam failure mode under the earthquake action in cooperation with weakening of the small rigidity of the cross section of the straining beam, and the occurrence position of a damaged plastic hinge is controlled to be located at a plastic energy dissipation node.

Description

Technical Field

[0001] The invention relates to the field of bridge engineering, and in particular to a bridge bent pier-tie beam node with a compressible bending steel plate. Background Art

[0002] With the development of social economy, bridges, as important structures that can cross rivers, valleys and other complex terrains, play an important role in my country's transportation network, especially in the western region where high-intensity earthquakes frequently occur. At present, in order to ensure that bridges are still passable after an E1 earthquake or can be quickly restored to traffic after an E2 earthquake, it is of great significance to install energy-absorbing devices in bridge structures that can achieve controllable earthquake damage and can be quickly replaced after an earthquake.

[0003] The bent pier is a common highway bridge substructure. Under the action of earthquakes, the beam end area of ​​the pier column-tie beam node is in a complex stress state under the action of bending moment, shear force and axial force, which is prone to damage, resulting in reduced bridge ductility and even collapse in severe cases. By weakening the stiffness of the tie beam end, that is, reducing the height of the tie beam section in this area and installing a special energy dissipation device, the plastic hinge position is effectively controlled to be transferred to the tie beam end, avoiding damage to the pier column body and improving the seismic performance of the bent pier. However, the traditional method of weakening the stiffness of the tie beam still has some problems. For example, while weakening the tie beam, it may cause weak links in the rest of the structure, reducing the structure's ability to resist progressive collapse. Summary of the invention

[0004] In order to protect the core area of ​​the pier column-tie beam node from damage, improve the seismic performance of the bridge, and achieve controllable earthquake damage and rapid recovery after an earthquake, the purpose of the present invention is to provide a bridge pier-tie beam node with a compressive bent steel plate.

[0005] The present invention provides the following technical solutions:

[0006] A bridge frame pier-tie beam node with a compressive bendable steel plate, which is arranged at the intersection of a pier column (1) and a tie beam (2), and comprises a weakened tie beam (3) located at the connecting end of the tie beam (2) facing the pier column (1), wherein the cross-sectional height of the weakened tie beam (3) is smaller than the cross-sectional height of the tie beam (2); a compressive bendable steel plate assembly (4) is located at the upper and lower sides of the weakened tie beam (3), and an anti-buckling cover plate assembly (5) respectively corresponds to and fixes the upper and lower bendable steel plate assemblies (4); and the two ends of the upper and lower bendable steel plate assemblies (4) are respectively fixedly connected to the pier column (1) and the tie beam (2).

[0007] According to some embodiments, a single bent steel plate assembly (4) includes a bent steel plate and two L-shaped compression steel plates (7), wherein the bent steel plate has an elastic bending portion, and the two ends of the bending portion are respectively fixedly connected to the two L-shaped compression steel plates (7) in the horizontal direction; the two L-shaped compression steel plates (7) are respectively fixedly connected to the pier (1) and the tie beam (2); the cover plate assembly (5) includes an upper cover plate and a lower cover plate that clamp the middle cover plate, wherein the middle cover plate is divided into two pieces in the front-to-back direction and is located on both sides of the L-shaped compression steel plate (7), and the upper and lower cover plates are fixed with bolts after clamping the middle cover plate on both sides, and an opening is provided in the upper cover plate corresponding to the bending of the bent steel plate.

[0008] According to some embodiments, the bent steel plate is a first bent steel plate (6), which includes a bent portion protruding outward and extension portions at both ends of the bent portion, and the extension portions are horizontally fitted and fixedly connected to two L-shaped compression steel plates (7) in the direction of the weakened tie beam (3).

[0009] According to some embodiments, the bent steel plate is a second bent steel plate (9), the second bent steel plate (9) includes a bent portion protruding outward, and the two ends of the bent portion are fixedly connected to the two inward ends of the two L-shaped compression steel plates (7); compression wing plates (10) are provided on both sides of the second bent steel plate (9), and the compression wing plates (10) are fixedly connected to the two sides of the two inward ends of the two L-shaped compression steel plates (7), extending horizontally inward and spaced a certain distance apart.

[0010] According to some embodiments, the cross-sectional width of the L-shaped compressed steel plate (7) is greater than the cross-sectional width of the first bent steel plate (6).

[0011] According to some embodiments, the bending portion is in a triangular or arc shape.

[0012] According to some embodiments, the bending parts of the bending portions are all provided with chamfers.

[0013] According to some embodiments, the pier column (1) and the tie beam (2) are connected to the L-shaped compression steel plate (7) via pre-embedded high-strength threaded screw rods.

[0014] According to some embodiments, the longitudinal reinforcements in the weakened tie beam (3) are bent upward and downward respectively to form inclined forked reinforcements (8).

[0015] According to some embodiments, the weakened tie beam (3) is provided with dense stirrups.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] Under the action of earthquake, the pier column-tie beam node will produce large bending moment and shear force. After decoupling the bending moment and shear force, the bent steel plates arranged on the upper and lower sides of the tie beam will bear the axial tension generated by the decoupling of the bending moment at the beam end under ideal conditions, and the weakened concrete section of the tie beam will bear the shear force generated by the decoupling. The bent steel plate assembly provided by the present invention has the characteristic of "secondary yield" when subjected to tension and compression. When the bent steel plate assembly is subjected to tension, the bent part of the bent steel plate enters the plastic stage from the elastic stage, the first yield occurs, and then enters the yield strengthening stage; when the bent steel plate is straightened, the second yield occurs, and then reaches the load limit point. When the bent steel plate assembly is under compression, the first yield point is the same as that under tension, and both are generated when the bent portion of the bent steel plate enters the plastic stage. The second yield point is that as the displacement of the plate end increases, contact extrusion occurs on one side of the L-shaped compression steel plate to increase the bearing capacity, and the correspondence between the tension and compression "secondary yield points" can be achieved by adjusting the distance of the straight section of the L-shaped compression steel plate. The compression bearing limit point of the L-shaped compression steel plate is the load limit point of the bent steel plate assembly. The bent steel plate assembly has the characteristics of "weak first and then strong" and large deformation capacity. Combined with the weakening of the small stiffness of the tie beam section, the frame pier under earthquake action can form a "strong column and weak beam" failure mode, and the location of the damaged plastic hinge is controlled at the plastic energy dissipation node. At the same time, when a large displacement occurs, the bent steel plate can provide a large bearing capacity, provide resistance to continuous collapse, and protect the frame pier structure system from damage.

[0018] Although traditional bent steel plate components have excellent tensile performance, their ultimate compressive bearing capacity is only equivalent to the one-time yield bearing capacity of the bent steel plate when under tension. As a result, the weakened tie beam section will bear part of the axial pressure generated by the section bending moment decoupling, causing the weakened tie beam section to be in a complex stress state, which has an adverse effect on the section bearing.

[0019] The second yield point of the compressive bendable steel plate assembly designed in the present invention when under compression is achieved in the following manner, that is, the L-shaped compressive steel plate welded to the bent steel plate slides in the anti-buckling cover plate assembly to prevent the second-order effect caused by the compression of the bent steel plate, so that the ends of the L-shaped compressive steel plate on both sides of the bending section are in contact and extrusion, providing a higher compressive bearing capacity, thereby matching the tensile bearing capacity of the bent steel plate, so that the weakened tie beam section only needs to bear the shear force generated by the section.

[0020] Aiming at the stress mechanism of this node, the present invention designs oblique forked steel bars 8 in the weakened tie beam section by bending the upper and lower longitudinal steel bars downward and upward respectively. Compared with the traditional weakened section reinforcement, the obliquely inserted steel bars can improve the shear bearing capacity, but will not improve the bending performance, which is conducive to achieving bending and shear separation.

[0021] At the same time, the compressive bent steel plate assembly can be bolted to the high-strength threaded screw embedded in the pier and tie beam only through one side of the L-shaped compressive steel plate, and is replaceable after an earthquake. As the main replaceable energy dissipation and shock absorption component, the compressive bent steel plate assembly will produce large plastic deformation under the action of an earthquake. The plastic development mainly occurs at the bend of the bent steel plate, thereby controlling the location of the plastic hinge in the node area. The connection between the bent steel plate assembly that may be damaged and the pier and tie beam is bolted, which is convenient for rapid replacement after earthquake damage, can save a lot of time cost, labor cost and maintenance cost, and is conducive to the rapid recovery of traffic after an earthquake. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the position of the bridge bent pier-tie beam node with the compressive bendable steel plate provided in Example 1 or Example 2 of the present invention;

[0023] Figure 2 It is a structural schematic diagram of a bridge bent pier-tie beam node with a compressive bendable steel plate provided in Example 1 or Example 2 of the present invention;

[0024] Figure 3 It is a schematic diagram of the internal reinforcement structure of the weakened tie beam 3 provided in Example 1 or Example 2 of the present invention;

[0025] Figure 4 It is a schematic diagram of the assembly of the first bent steel plate and the cover plate assembly provided in Example 1 of the present invention;

[0026] Figure 5 It is a schematic diagram of the assembled state and disassembled state of the cover plate assembly provided in Example 1 of the present invention.

[0027] Figure 6 It is a schematic diagram of the first bent steel plate structure and assembly in the bent steel plate assembly provided in Example 1 of the present invention.

[0028] Figure 7 It is a schematic diagram of the second bent steel plate structure and assembly in the bent steel plate assembly provided in Example 2 of the present invention.

[0029] In the figure:

[0030] Pier column 1; tie beam 2; weakened tie beam 3; bent steel plate assembly 4; cover plate assembly 5; first bent steel plate 6; L-shaped compression steel plate 7; oblique fork steel bar 8; second bent steel plate 9; compression wing plate 10. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0032] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. In addition, unless otherwise clearly specified and limited, the terms "set", "install", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] The present invention will be further described below in conjunction with the accompanying drawings.

[0034] Example 1

[0035] like Figure 1 to Figure 2 As shown, this embodiment provides a bridge bent pier-tie beam node with a compressive bendable steel plate, which is arranged at the intersection of a pier column 1 and a tie beam 2, and comprises: a weakened tie beam 3 located at the connecting end of the tie beam 2 toward the pier column 1, a compressive bendable steel plate assembly 4 located at the upper and lower sides of the weakened tie beam 3, and an anti-buckling cover plate assembly 5 arranged on the bendable steel plate assembly 4;

[0036] The purpose of weakening the tie beam 3 is to reduce the cross-sectional height of the tie beam within a certain range at the end of the tie beam of the bent pier to achieve the purpose of reducing the cross-sectional stiffness, and two bent steel plate assemblies 4 energy-absorbing components are respectively installed on the upper and lower sides of the weakened tie beam 3. At the same time, since the bent steel plate assemblies 4 have a stress mechanism of early yield and early energy consumption, the initial stiffness is also relatively low, and damage will preferentially occur at the position of the set new energy-absorbing node, realizing the transfer of plastic hinges and controllability of damage under earthquake action. Based on the moment-shear decoupling stress mechanism of this node, in order to increase the shear bearing capacity of the weakened tie beam 3, the longitudinal reinforcements configured in the weakened tie beam 3 are bent upward and downward respectively to form the form of inclined forked steel bars 8, and the stirrups are densely reinforced, such as Figure 3 .

[0037] like Figure 6 The compressive bending steel plate assembly 4 includes a first bending steel plate 6 and an L-shaped compressive steel plate 7. The left figure shows the first bending steel plate 6 welded to the L-shaped compressive steel plate 7, and the right figure shows the schematic diagram of the separation state before welding. The first bending steel plate 6 is the main force-bearing and energy-consuming component, and the bending shape of the middle part is similar to a triangle or arc. Chamfers are performed at each bending angle to prevent stress concentration. The bending shape position of the bending steel plate assembly 4 on the upper and lower sides of the weakening tie beam 3 is mirror-symmetrical relative to the center of the tie section. One side of the L-shaped compression steel plate 7 is connected and fixed to the high-strength threaded screw embedded in the pier 1 and the tie beam 2 by bolts, and the other side thereof is welded to the straight sections on the left and right sides of the bending section of the first bent steel plate 6 respectively, so that when the bent steel plate assembly 4 is under pressure, the vertical displacement of the L-shaped compression steel plate 7 is limited, thereby limiting the second-order effect of the first bent steel plate 6 when under pressure, so that in the case of large deformation, the plate ends on one side of the two L-shaped compression steel plates 7 that are welded to the left and right sides of the bending section of the first bent steel plate 6 can be contacted and extruded, providing a certain compressive bearing capacity, and reducing the adverse effect of weakening the force in the cross section of the tie beam 3.

[0038] Figure 6 The L-shaped compressive steel plate 7 in the left figure has a larger cross-sectional width d of the steel plate on its left and right sides compared to the first bent steel plate 6. One side of the L-shaped compressive steel plate 7 is connected to the pier 1 and the tie beam 2 by bolts, and the other side is welded to the straight sections on the left and right of the bent section of the first bent steel plate 6.

[0039] like Figures 4-5 The cover plate assembly 5 for preventing buckling is divided into three layers. Since the L-shaped compression steel plate 7 is wider than the first bent steel plate 6, the portion of the L-shaped compression steel plate 7 that exceeds the first bent steel plate 6 can be clamped by the upper and lower layers of the cover plate assembly 5 to limit the vertical displacement of the L-shaped compression steel plate 7. The middle layer cover plate is mainly used to facilitate the fixing of the upper and lower layers of the cover plates by bolts. Figure 5 The left picture in the middle is a schematic diagram of the combined state, and the right picture is a schematic diagram of the split state.

[0040] This embodiment will achieve sufficient stiffness and bearing capacity under the action of E1 earthquake by setting energy dissipation devices within a certain range of the ends of the tie beams of the bent piers, and the whole is in the elastic stage; under the action of E2 earthquakes and rare earthquakes, the main plastic deformation is concentrated in the bent steel plate assembly 4. Since the initial stiffness of the weakened tie beam 3 and the bent steel plate assembly 4 is relatively low, the plastic hinge generated in the core area of ​​the pier-tie beam node under the action of the earthquake is transferred to the node area with the energy dissipation device, realizing the transfer and control of the plastic hinge. At the same time, the bent steel plate assembly 4 is connected to the pier 1 and the tie beam 2 by bolts. When plastic deformation or even damage occurs, it can be quickly replaced, with good replaceability, effectively realizing the rapid recovery of traffic after the earthquake.

[0041] Example 2

[0042] like Figure 7 As shown, this embodiment provides another structure of a compressive bent steel plate assembly 4, and its installation position and installation method are the same as those of Example 1. It is located at the intersection of the pier 1 and the tie beam 2 and is bolted to the pre-buried high-strength threaded screw. Different from Example 1, the structure of the compressive bent steel plate assembly 4 of this embodiment includes a second bent steel plate 9, an L-shaped compressive steel plate 7 and a compressive wing plate 10. The bent ends of the second bent steel plate 9 are welded between the two inward ends of the two L-shaped compressive steel plates 7; the four compressive wing plates 10 are respectively welded to the two sides of the L-shaped compressive steel plate 7 toward the middle, and the second bent steel plate 9 is located in the middle of the compressive wing plates 10 on both sides. The compressive wing plates 10 all extend horizontally inward, but do not touch, and there is a certain distance between them. Similar to Example 1, the L-shaped compressive steel plate 7 of this embodiment has a greatly increased cross-sectional width compared to the second bent steel plate 9, which is convenient for connection with the pier 1 and the tie beam 2. At the same time, compression wing plates 10 are welded on both sides of the L-shaped compression steel plate 7. The three-layer cover plate assembly 5 realizes the collision and extrusion of the compression wing plates 10 on both sides of the second bent steel plate 9 by limiting the vertical displacement of the L-shaped compression steel plate 7 and the compression wing plates 10, thereby providing compressive bearing capacity, which corresponds to the tensile bearing capacity of the second bent steel plate 9, thereby reducing the adverse effect of weakening the tie beam 3.

[0043] The main difference between Example 1 and Example 2 lies in the bent steel plate assembly 4, wherein the advantage of Example 1 is that the collision and extrusion area of ​​the L-shaped compression steel plate 7 in its bent steel plate assembly 4 is larger than that in Example 2, and can provide greater compressive bearing capacity; the advantage of Example 2 is that its bent steel plate assembly 4 has only one layer of steel plate, which is simpler than the two-layer structure of the bent steel plate assembly 4 of Example 1, and at the same time makes the structure of the cover plate assembly 5 of Example 2 also simpler.

[0044] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A bridge bent pier-tie beam node with a compressive bendable steel plate, which is arranged at the intersection of a pier column (1) and a tie beam (2), characterized in that: It comprises a weakened tie beam (3) located at the connection end of the tie beam (2) facing the pier (1), wherein the cross-sectional height of the weakened tie beam (3) is smaller than the cross-sectional height of the tie beam (2); a compressive bending steel plate assembly (4) is located at the upper and lower sides of the weakened tie beam (3), and an anti-buckling cover plate assembly (5) respectively corresponds to and fixes the upper and lower bent steel plate assemblies (4); and the two ends of the upper and lower bent steel plate assemblies (4) are respectively fixedly connected to the pier (1) and the tie beam (2).

2. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 1, characterized in that: A single bent steel plate assembly (4) comprises a bent steel plate and two L-shaped pressure-bearing steel plates (7), wherein the bent steel plate has an elastic bent portion, and the two ends of the bent portion are respectively fixedly connected to the two L-shaped pressure-bearing steel plates (7) in the horizontal direction; the two L-shaped pressure-bearing steel plates (7) are respectively fixedly connected to the pier (1) and the tie beam (2); the cover plate assembly (5) comprises an upper cover plate and a lower cover plate that clamp an intermediate cover plate, wherein the intermediate cover plate is divided into two pieces in the front-to-back direction and is located on both sides of the L-shaped pressure-bearing steel plate (7), and the upper and lower cover plates are fixed by bolts after clamping the intermediate cover plate on both sides, and an opening is provided in the upper cover plate corresponding to the bent portion of the bent steel plate.

3. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 2, characterized in that: The bent steel plate is a first bent steel plate (6), which comprises a bent portion protruding outward and extension portions at both ends of the bent portion, wherein the extension portions are horizontally fitted and fixedly connected to two L-shaped compression steel plates (7) in the direction of the weakened tie beam (3).

4. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 2, characterized in that: The bent steel plate is a second bent steel plate (9), the second bent steel plate (9) comprises a bent portion protruding outward, the two ends of the bent portion are fixedly connected to the two inward ends of the two L-shaped pressure steel plates (7); pressure wing plates (10) are provided on both sides of the second bent steel plate (9), the pressure wing plates (10) are fixedly connected to the two inward ends of the two L-shaped pressure steel plates (7), extend horizontally inward and are spaced a certain distance apart.

5. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 2, characterized in that: The cross-sectional width of the L-shaped compressed steel plate (7) is greater than the cross-sectional width of the first bent steel plate (6).

6. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 2, characterized in that: The shape of the bending portion is a triangle or an arc.

7. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 6, characterized in that: The bending parts of the bending portions are all provided with chamfers.

8. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 2, characterized in that: The pier column (1) and the tie beam (2) are connected to the L-shaped pressure steel plate (7) via pre-buried high-strength threaded screw rods.

9. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 1, characterized in that: The longitudinal reinforcements in the weakened tie beam (3) are bent upward and downward respectively to form oblique forked reinforcements (8).

10. The bridge bent pier-tie beam node with compressive bendable steel plate according to claim 9, characterized in that: The weakened tie beam (3) is provided with dense stirrups.

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