Connection structure and construction method of negative moment zone of steel-concrete composite continuous beam

Abstract

The present invention provides a connection structure of a steel-concrete composite continuous beam in a negative bending moment zone, comprising steel main beams arranged at intervals and end cross beams located between adjacent steel main beams, and an open hole connection steel plate is arranged between the tops of adjacent steel main beams, and the open hole connection steel plate is provided with a plurality of first shear nails for fixing the open hole connection steel plate to the upper flange plate. The present invention has a reasonable design and a simple structure, and the upper flanges of adjacent steel main beams are connected as one by inserting the shear nails on the top of the steel main beam through the open hole connection steel plate, which effectively solves the problem of discontinuity at the end of the steel main beam, and at the same time improves the adverse effects of compression of the steel beam and tension of the concrete slab in the negative bending moment zone of the steel-concrete composite simply supported continuous beam, thereby ensuring the overall force performance and seismic performance of the steel-concrete composite continuous beam.

Description

Technical Field

[0001] The invention relates to a connection structure of a negative bending moment zone of a steel-concrete composite continuous beam and a construction method thereof. Background Art

[0002] As we all know, steel-concrete simply supported composite beams have the advantages of simple structure, clear force, and good ductility because they give full play to the material properties of steel's tensile strength and concrete's high compressive strength. In addition, simply supported composite beam bridges are easy to construct, have a high degree of prefabrication, and can adapt to foundations with large settlements. They are popular in small and medium spans. However, they have disadvantages such as large mid-span bending moment, large mid-span deflection, limited span, and multiple piers. Therefore, they are not suitable for medium or large span bridges.

[0003] The steel-concrete continuous composite beam is subjected to negative bending moment at the support and positive bending moment at the mid-span. The mid-span bending moment is much smaller than that of the equal-span simply supported beam. The negative bending moment at the support has an unloading effect on the positive bending moment at the mid-span, making the internal force state more uniform and reasonable. Therefore, the beam height can be reduced. Therefore, it has the advantages of large clearance under the bridge, large span capacity, large rigidity, and light structural weight. Therefore, in medium or large span bridges, steel-concrete continuous composite beams have been widely used in the engineering community. However, in its negative bending moment section, the concrete is tensile, the upper edge of the steel beam is tensile, and the lower edge of the steel beam is compressed, which will have an adverse effect on the deflection, rigidity, and slip of the continuous composite beam. However, this adverse effect can be improved through engineering.

[0004] Simple support first and then continuous is the most commonly used construction method for continuous composite beams. By casting the end crossbeams at the ends of the simply supported beams, the structural system is converted from simple support to continuous. The composite beam bridge that is simply supported first and then continuous effectively overcomes the shortcomings of simply supported beams and continuous beams, and combines the advantages of both, making the structure more reasonable. The construction method of simply supported first and then continuous utilizes the prefabrication and erection methods of simply supported beams, which is convenient for construction, and the corresponding structural dimensions are easy to standardize, providing support for large-scale prefabrication production and improving construction efficiency. Although the adjacent simply supported beams are connected together by introducing the end crossbeam structure at the bridge support to form a continuous system bridge, in essence, the steel beams of the adjacent simply supported composite beams are not directly connected and are still in the form of steel beam interruption. Therefore, during the use stage of the bridge, the end crossbeams at the pier top support will be subjected to large negative bending moments and shear forces, resulting in unfavorable factors such as tension of the cast-in-place concrete slab at the pier top and compression of the lower edge of the steel beam. Therefore, the bridge deck at the wet joint end structure of the simply supported continuous beam will prematurely develop longitudinal and transverse cracks, thereby reducing the durability of the structure and affecting the service life of the bridge structure. Therefore, the beam end connection in the simply supported to continuous system has always been the focus of continuous composite beams.

[0005] At present, in the design, the width of the cracks in the bridge deck at the wet joint end structure is usually controlled by increasing the reinforcement ratio at the end beam, or prestressed tendons are further set at the concrete top plate near the support to resist negative bending moment, thereby reducing the cracks in the bridge deck. However, increasing the reinforcement ratio of ordinary steel bars has limited control over the crack width of the bridge deck at the pier top, and the effect of applying prestressing is not obvious due to the influence of concrete creep. Summary of the invention

[0006] The present invention improves the above-mentioned problem, that is, the technical problem to be solved by the present invention is to provide a connection structure and a construction method for the negative bending moment zone of a steel-concrete composite continuous beam, which effectively solves the problem of discontinuity at the ends of the steel beams, and at the same time improves the adverse effects of compression on the steel beams and tension on the concrete slabs in the negative bending moment zone of the steel-concrete composite simply supported continuous beam, thereby ensuring the overall stress performance and seismic resistance of the steel-concrete composite continuous beam.

[0007] The specific implementation scheme of the present invention is: to provide a connection structure of the negative bending moment zone of a steel-concrete composite continuous beam, comprising steel main beams arranged at intervals and end cross beams located between adjacent steel main beams, and open hole connecting steel plates are arranged between the tops of adjacent steel main beams, and the open hole connecting steel plates are provided with a plurality of first shear nails for fixing the open hole connecting steel plates to the upper flange plates.

[0008] Furthermore, each steel main beam includes an upper flange plate, a web plate and a lower flange plate arranged from top to bottom, the first shear nails are evenly arranged on the upper surface of the upper flange plate, the perforated connecting steel plate is installed between the tops of adjacent upper flange plates, and holes for passing the first shear nails are arranged on both sides of the perforated connecting steel plate, and the two adjacent upper flange plates are connected through the perforated connecting steel plate.

[0009] Furthermore, a steel cage is arranged in the end cross beam, and the steel cage is composed of staggered transverse steel bars and stirrups.

[0010] Furthermore, vertical reinforcing ribs are arranged on both sides of the web, and a plurality of second shear nails are evenly arranged on one side of the vertical reinforcing ribs close to the end cross beam.

[0011] Furthermore, a preset circular hole is provided on the web inside the end cross beam for passing the transverse reinforcement.

[0012] Furthermore, a top steel plate is vertically welded to the inner end of the lower flange plate, and a filling steel plate is arranged between the two top steel plates.

[0013] Furthermore, the width of the perforated connecting steel plate is smaller than the width of the upper flange plate, and fillet welds are used to weld the two side edges of the perforated connecting steel plate along the length direction of the perforated connecting steel plate to the upper flange plate.

[0014] Furthermore, a gap of 5 mm to 20 mm is left between adjacent top steel plates for inserting a filling steel plate of corresponding thickness.

[0015] Furthermore, the spacing between the open hole connecting steel plate and the upper flange plate is 0~150mm.

[0016] Furthermore, two layers of perforated connecting steel plates are arranged above the upper flange plate, and the spacing between the two layers of perforated connecting steel plates is 60-200 mm.

[0017] Furthermore, a construction method for the connection structure of the negative bending moment zone of a steel-concrete composite continuous beam includes the following steps: (1) processing the steel main beam: processing the components of the steel main beam according to the steel main beam processing drawing, reserving a preset circular hole on the web plate, assembling and welding the upper flange plate, the lower flange plate and the web plate, welding the top steel plate to the inner end of the lower flange plate, welding the vertical stiffening rib steel plate on both sides of the web plate, and welding the second shear nail on the surface of the side close to the end cross beam, and welding the shear nail on the surface of the upper flange of the steel beam; (2) processing the connecting steel plate: processing a hole at the position of the connecting steel plate corresponding to the first shear nail, and the center line of the hole needs to be aligned with the center line of the first shear nail; (3) erecting the steel main beam: transporting the steel main beam to the construction site, and erecting the steel main beam by hoisting, pushing or dragging. A temporary support is placed under the vertical stiffening rib at the end of the steel main beam. After the steel main beam is installed and fixed, a permanent support is installed between the two adjacent steel main beams; (4) steel cage Construction: Tie up the transverse steel bars and stirrups. Some of the transverse steel bars need to pass through the preset circular holes of the two adjacent webs to form a steel cage in the end cross beam; (5) Install the perforated connecting steel plate: Align the preset circular holes of the perforated connecting steel plate and insert the first shear nails of the adjacent upper flange. If the design requires the perforated connecting steel plate to be welded to the upper flange, welding construction is required; (6) End cross beam construction: Support the formwork according to the size of the end cross beam, pour concrete and maintain. When the concrete strength reaches the demolding strength, the formwork can be removed so that the steel main beam is connected in the longitudinal direction of the bridge; (7) Bridge deck concrete layer construction: Install the bridge deck concrete bottom formwork and side formwork, tie up the bridge deck steel bars, pour concrete and maintain. When the concrete meets the design requirements, the formwork can be removed; (8) In addition, in step (5), the installation of the perforated connecting steel plate can also be placed after the end cross beam construction; in step (7), the bridge deck concrete layer construction can be constructed together with the end cross beam concrete.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the device has a simple structure and a reasonable design. The upper flanges of adjacent steel main beams are connected by opening a connecting steel plate and inserting the shear nails on the upper flange of the steel main beam, thereby effectively solving the problem of discontinuity at the ends of the steel beams, and at the same time improving the adverse effects of compression of the steel beam and tension of the concrete slab in the negative bending moment zone of the steel-concrete composite simply supported continuous beam, thereby ensuring the overall force performance and seismic performance of the steel-concrete composite continuous beam; at the same time, it avoids the problems of high cost, complicated construction, and poor crack width control effect caused by the use of tensioned high-strength prestressed tendons and increased reinforcement ratio of ordinary steel bars, and effectively improves the adverse effects of tensile cracking of the concrete slab in the negative bending moment section of the steel-concrete composite continuous beam and poor structural durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural elevation view of Example 1 of the present invention;

[0020] Figure 2 It is a structural cross-sectional view of Example 1 of the present invention;

[0021] Figure 3 It is a structural plan view of Example 1 of the present invention;

[0022] Figure 4 It is a structural elevation view of Example 2 of the present invention;

[0023] Figure 5 It is a structural plan view of Example 2 of the present invention;

[0024] Figure 6 It is a structural elevation view of Example 3 of the present invention;

[0025] Figure 7 It is a structural elevation view of Example 4 of the present invention;

[0026] In the figure: 1-upper flange plate; 2-lower flange plate; 3-web plate; 4-opening connection steel plate; 5-first shear nail; 6-top steel plate; 7-filling steel plate; 8-transverse reinforcement; 9-stirrups; 10-opening; 11-preset circular hole; 12-vertical stiffening rib; 13-fillet weld; 14-end cross beam; 15-bridge deck concrete layer; 16-second shear nail. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] In the first embodiment of the present invention, Figures 1 to 3As shown, a connection structure of a negative bending moment zone of a steel-concrete composite continuous beam is provided, comprising steel main beams arranged at intervals and end cross beams 14 located between adjacent steel main beams, and an open hole connecting steel plate 4 is arranged between the tops of adjacent steel main beams, and the open hole connecting steel plate is provided with a plurality of first shear nails 5 for fixing the open hole connecting steel plate to the upper flange plate.

[0029] Each of the above-mentioned steel main beams includes an upper flange plate 1, a web plate 3 and a lower flange plate 2 arranged from top to bottom, the upper end of the web plate is connected to the upper flange plate, and the lower end of the web plate is connected to the lower flange plate. The first shear nails are evenly arranged on the upper surface of the upper flange plate, and the adjacent upper flange plates are arranged at intervals. The perforated connecting steel plate is installed between the tops of adjacent upper flange plates. Openings 10 for passing the first shear nails are arranged on both sides of the perforated connecting steel plate. The first shear nail passes through the opening and connects the two adjacent upper flange plates through the first shear nails in the opening.

[0030] The end cross beam is a reinforced concrete structure and is used to connect the ends of adjacent steel main beams.

[0031] The concrete material used in the above-mentioned end cross beam is ordinary concrete, or high performance concrete, or ultra-high performance concrete, or steel fiber concrete.

[0032] A steel cage is arranged inside the above-mentioned end cross beam, and the steel cage is composed of transverse steel bars 8 and stirrups 9 arranged in a staggered manner.

[0033] Vertical reinforcing ribs 12 are arranged on both sides of the web, and a plurality of second shearing studs 16 are evenly arranged on one side of the vertical reinforcing rib close to the end cross beam.

[0034] The web located inside the end cross beam is provided with a preset circular hole 11 for passing the transverse reinforcement.

[0035] A top steel plate 6 is vertically welded to the inner end of the lower flange plate, and a filling steel plate 7 is arranged between the two top steel plates.

[0036] A gap of 5mm~20mm is left between adjacent top steel plates. After the steel main beam is installed in place, a filling steel plate of corresponding thickness is inserted into the gap.

[0037] A bridge deck concrete layer 15 is arranged above the above-mentioned steel main beam.

[0038] In the second embodiment of the present invention, based on the first embodiment, as Figures 4 and 5 As shown, the width of the perforated connecting steel plate is smaller than the width of the upper flange plate, and the two side edges of the perforated connecting steel plate along the length direction of the perforated connecting steel plate are welded to the upper flange plate by fillet welds 13.

[0039] In the third embodiment of the present invention, based on the first embodiment, as Figure 6As shown, the spacing between the open hole connecting steel plate and the upper flange plate is 0~150mm.

[0040] In the fourth embodiment of the present invention, based on the first embodiment, as Figure 7 As shown, two layers of perforated connecting steel plates are arranged above the upper flange plate, the perforated connecting steel plates at the lower layer are close to the surface of the upper flange plate, and the spacing between the two layers of perforated connecting steel plates is 60~200mm.

[0041] In this embodiment, the construction steps are as follows:

[0042] (1) Processing of steel main beams: Process the various components of the steel main beam according to the processing drawings of the steel main beams, reserve preset circular holes on the webs, assemble and weld the upper flange plate, lower flange plate and webs, weld the top steel plate to the inner end of the lower flange plate, weld the vertical stiffening rib steel plates on both sides of the webs, and weld the second shear studs on the surface of the side close to the end beam, and weld the shear studs on the surface of the upper flange of the steel beam;

[0043] (2) Processing the connecting steel plate: Process a hole at the position of the connecting steel plate corresponding to the first shear nail, and the center line of the hole must be aligned with the center line of the first shear nail;

[0044] (3) Erection of steel main beams: transport the steel main beams to the construction site and use hoisting, jacking or dragging methods to erect the steel main beams. Place temporary supports under the vertical stiffening ribs at the ends of the steel main beams. After the steel main beams are installed and fixed, install permanent supports between two adjacent steel main beams.

[0045] (4) Steel cage construction: Tie transverse steel bars and stirrups. Some transverse steel bars need to pass through the preset circular holes of two adjacent webs to form a steel cage in the end beam.

[0046] (5) Install the perforated connecting steel plate: Align the preset circular holes of the perforated connecting steel plate and insert the first shear nail of the adjacent upper flange. If the design requires welding of the perforated connecting steel plate and the upper flange, welding construction is required;

[0047] (6) End cross beam construction: according to the size of the end cross beam, formwork is supported, concrete is poured and maintained, and the formwork can be removed when the concrete strength reaches the demolding strength, so that the steel main beam is connected in the longitudinal direction of the bridge;

[0048] (7) Construction of bridge deck concrete layer: Install the bottom and side forms of the bridge deck concrete, tie the bridge deck reinforcement, pour concrete and maintain it. When the concrete meets the design requirements, the formwork can be removed.

[0049] In step (5), the installation of the opening connection steel plate can be placed after the construction of the end cross beam;

[0050] In step (7), the bridge deck concrete layer can be constructed together with the end beam concrete.

[0051] Unless otherwise stated, any technical solution disclosed in the present invention disclosed above, if it discloses a numerical range, then the disclosed numerical range is a preferred numerical range, and any technician in the field should understand that the preferred numerical range is only a numerical value with a more obvious technical effect or representative value among many implementable numerical values. Since there are too many numerical values ​​to be exhaustive, the present invention discloses some numerical values ​​to illustrate the technical solution of the present invention, and the numerical values ​​listed above should not constitute a limitation on the scope of protection of the present invention.

[0052] If the words "first", "second" and so on are used in this article to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of description to distinguish the components. Unless otherwise stated, the above words have no special meaning.

[0053] At the same time, if the above-mentioned invention discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connection using bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by one-piece molding using a casting process) (except when it is obviously impossible to use an one-piece molding process).

[0054] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in the present invention include states or shapes that are approximate, similar, or close to them.

[0055] Any component provided by the present invention may be assembled from a plurality of separate components, or may be a separate component manufactured by an integral forming process.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A connection structure of a negative moment zone of a steel-concrete composite continuous beam, characterized in that: It comprises steel main beams arranged at intervals and end cross beams located between adjacent steel main beams, an open hole connecting steel plate is arranged between the tops of adjacent steel main beams, and the open hole connecting steel plate is provided with a plurality of first shear nails for fixing the open hole connecting steel plate to the upper flange plate; Each steel main beam comprises an upper flange plate, a web plate and a lower flange plate arranged from top to bottom, the first shear nails are evenly arranged on the upper surface of the upper flange plate, the perforated connecting steel plate is installed between the tops of adjacent upper flange plates, both sides of the perforated connecting steel plate are provided with openings for passing the first shear nails, and the two adjacent upper flange plates are connected through the perforated connecting steel plate; A steel cage is arranged in the end cross beam, and the steel cage is composed of staggered transverse steel bars and stirrups; Vertical reinforcing ribs are arranged on both sides of the web, and a plurality of second shear nails are evenly arranged on one side of the vertical reinforcing ribs close to the end cross beam; Pre-set circular holes are provided on the web inside the end cross beam for the transverse reinforcement to pass through; A top steel plate is vertically welded at the inner end of the lower flange plate, and a filling steel plate is arranged between the two top steel plates; a gap of 5mm to 20mm is left between adjacent top steel plates for inserting a filling steel plate of corresponding thickness; The width of the perforated connecting steel plate is smaller than the width of the upper flange plate, and the two side edges of the perforated connecting steel plate along the length direction of the perforated connecting steel plate are welded to the upper flange plate by fillet welds; The spacing between the perforated connecting steel plate and the upper flange plate is 0~150mm, or two layers of perforated connecting steel plates are arranged above the upper flange plate, the perforated connecting steel plates on the lower layer are close to the surface of the upper flange plate, and the spacing between the two layers of perforated connecting steel plates is 60~200mm.

2. A construction method using the connection structure of the negative moment zone of the steel-concrete composite continuous beam as claimed in claim 1, characterized in that: The steps are as follows: (1) Processing of steel main beams: Process the components of the steel main beams according to the processing drawings of the steel main beams, reserve preset circular holes on the webs, assemble and weld the upper flange plates, lower flange plates and webs, weld the top steel plates to the inner ends of the lower flange plates, weld vertical stiffening rib steel plates on both sides of the webs, and weld the second shear nails on the surface of the side close to the end cross beam, and weld the shear nails on the surface of the upper flange of the steel beams at the same time; (2) Processing of connecting steel plates: Process holes at the positions of the connecting steel plates corresponding to the first shear nails, and the center lines of the holes must be aligned with the center lines of the first shear nails; (3) Erection of steel main beams: Transport the steel main beams to the construction site, and use hoisting, pushing or dragging methods to erect the steel main beams. Place temporary supports under the vertical stiffening ribs at the ends of the steel main beams. After the steel main beams are installed and fixed, install permanent supports between the two adjacent steel main beams; (4) Construction of steel cages: Tie transverse steel bars and stirrups, and partially The transverse reinforcement needs to pass through the preset circular holes of the two adjacent webs to form a reinforcement cage in the end cross beam; (5) Installation of the perforated connecting steel plate: align the preset circular holes of the perforated connecting steel plate and insert them into the first shear nails of the adjacent upper flange. If the design requires the perforated connecting steel plate to be welded to the upper flange, welding construction is required; (6) Construction of the end cross beam: support the formwork according to the size of the end cross beam, pour concrete and maintain it. When the concrete strength reaches the demolding strength, the formwork can be removed so that the steel main beam is connected in the longitudinal direction of the bridge; (7) Construction of the bridge deck concrete layer: install the bridge deck concrete bottom formwork and side formwork, tie the bridge deck steel bars, pour concrete and maintain it. When the concrete meets the design requirements, the formwork can be removed; (8) In addition, in step (5), the installation of the perforated connecting steel plate can also be placed after the construction of the end cross beam; in step (7), the construction of the bridge deck concrete layer can be constructed together with the end cross beam concrete.

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