Steel-concrete structure type simply-supported and then continuous composite beam and construction method thereof

Abstract

This application relates to a steel-concrete composite beam structure with a simple-supported-then-continuous design and its construction method, belonging to the technical field of steel-concrete structural beams. It includes steel pipe columns, multiple of which are arranged along the direction of the composite beam; connecting beams, located at the top of the steel pipe columns; corbels, connecting the connecting beams, extending away from the connecting beams along the direction of the composite beam, with multiple anchors fixedly connected to their outer walls; and cast-in-place beams, connecting two adjacent connecting beams. The corbels are embedded in the cast-in-place beams, and the length of the corbels is greater than the negative bending moment length of the cast-in-place beams in the span. The corbels pass through the connecting beams, with both ends protruding from the sides of the connecting beams. This application has the effect of improving construction efficiency and simplifying the construction process.

Description

Technical Field

[0001] This application relates to the technical field of steel-concrete composite beams, and in particular to a steel-concrete composite beam that is first simply supported and then continuous, and its construction method. Background Technology

[0002] The simple-supported-then-continuous beam method combines the advantages of continuous beams and the mass production of precast beams, thus gaining widespread application and development. Bridge construction using this method involves first prefabricating the simply supported beams in a prefabrication yard, then transporting and hoisting them onto temporary supports atop the piers. Next, the concrete for the wet joints between the beams is poured, and the negative bending moment prestressing at the wet joints atop the beams is tensioned. Finally, the temporary supports are removed, and the continuous beam is placed onto permanent supports, completing the system transformation from simply supported to continuous.

[0003] Currently, most beams that are initially simply supported and then become continuous employ the technique of applying prestress by post-tensioning the steel strands within the beam body in the negative bending moment zone. This involves pre-embedding prestressed steel strand ducts within the precast beam, and then tensioning the top slab prestressed steel strands and anchoring them to the precast beam once the wet joints between the precast beams reach the design strength. The prestressed strands are then used to overcome the problem of concrete cracking.

[0004] Regarding the aforementioned technologies, the inventors discovered that, since prestressed beams contain prestressed tendons, the fabrication of prestressed beams involves steps such as threading tendons, splicing tendons, tensioning, and grouting. These steps are complex and the process is cumbersome, which leads to low construction efficiency and a long construction period for simply supported beams followed by continuous beams. Summary of the Invention

[0005] To improve construction efficiency and simplify construction processes, this application provides a steel-concrete composite beam with a simple-supported-then-continuous structure and its construction method.

[0006] Firstly, this application provides a steel-concrete composite beam with a simple-supported-then-continuous structure and its construction method, which adopts the following technical solution:

[0007] A steel-concrete composite beam structure, initially simply supported and then continuously supported, includes:

[0008] Multiple steel pipe columns are provided along the direction of the composite beam;

[0009] The connecting beam is installed at the top of the steel pipe column;

[0010] The corbel, connecting the connecting beam, extends away from the connecting beam along the direction of the composite beam, and has multiple anchors fixedly connected to its outer wall.

[0011] Cast-in-place beams connect two adjacent connecting beams;

[0012] The corbel is embedded in the cast-in-place beam, and the length of the corbel is greater than the negative bending moment length of the cast-in-place beam in the span.

[0013] By adopting the above technical solution, the length of the corbel is greater than the negative bending moment length of the cast-in-place beam in the span. This allows the corbel to bear the corresponding negative bending moment after the beam is converted from a simply supported beam to a continuous beam, avoiding direct tension on the cast-in-place concrete. Therefore, there is no need to add prestressing tendons to the continuous beam. Compared with the existing simply supported beam system, this method simplifies the connection between the concrete beam and the steel pipe column and the process of tensioning prestress. The beam structure and the construction process of converting from simply supported to continuous are simpler, improving construction efficiency and greatly shortening the construction period. The anchors used on the corbel are used to connect the cast-in-place beam. The anchors are embedded in the cast-in-place beam, which increases the connection area and enhances the shear strength of the contact surface between the corbel and the cast-in-place beam, making the corbel and the surface of the cast-in-place beam more firmly bonded and able to share the load better.

[0014] Optionally, the corbel is inserted into the connecting beam, with both ends protruding from both sides of the connecting beam.

[0015] By adopting the above technical solution, the corbels extending from both sides of the continuous beam are formed by a single corbel inserted into the connecting beam, which makes the connection between the corbel and the connecting beam simpler, and at the same time improves the integrity of the corbel, enabling it to transfer the load to the connecting beam more evenly.

[0016] Optionally, a hinge support is provided on the inner bottom wall of the connecting beam, and the bracket is hinged to the hinge support.

[0017] By adopting the above technical solution, the horizontal angle of the corbel can be adjusted before casting the cast-in-place beam, so that the corbel can be better adapted to composite beams with different inclinations and orientations, thus increasing the applicability of the corbel.

[0018] Optionally, the inner bottom wall of the connecting beam is threaded with a plurality of leveling bolts that abut against the bracket.

[0019] By adopting the above technical solution, the leveling bolt supports the bracket. By adjusting the leveling bolt, the horizontal angle of the bracket can be changed. At the same time, the leveling bolt also acts as a load-bearing component, transferring part of the load of the bracket to the connecting beam below.

[0020] Optionally, the inner top wall of the connecting beam is threaded with a plurality of clamping bolts that abut against the bracket.

[0021] By adopting the above technical solution, the clamping bolts can tighten the bracket and lock its position, making it less likely for the bracket to be misaligned when pouring the cast-in-place beam. It can also increase the force transfer area between the connecting beam and the concrete when pouring the concrete at the top of the connecting beam later.

[0022] Optionally, the connecting beam is provided with multiple chambers through which the corbels pass, and reinforcing ribs are provided between the side walls of adjacent chambers.

[0023] By adopting the above technical solution, setting multiple corbels can better bear the negative bending moment of the composite beam, resulting in more uniform stress distribution and also increasing the width of the composite beam.

[0024] Optionally, the cast-in-place beam is provided with a continuous longitudinal reinforcement bar, and a positioning ring for the continuous longitudinal reinforcement bar to pass through is fixedly connected to the connecting beam.

[0025] By adopting the above technical solution, the positioning ring can play a positioning role for the longitudinal reinforcement bars. At the same time, the connection between the longitudinal reinforcement bars and the positioning ring does not need to be tied with binding wire, which improves the binding efficiency of the longitudinal reinforcement bars and shortens the construction period.

[0026] Optionally, the cast-in-place beam is provided with longitudinal reinforcement bars between spans, and the connecting beam is fixedly connected with a threaded sleeve for connecting the longitudinal reinforcement bars between spans.

[0027] By adopting the above technical solution, the connection between the non-continuous longitudinal reinforcement and the threaded sleeve is more convenient, which improves construction efficiency.

[0028] Optionally, the anchor may be either a stud or a bolt.

[0029] By adopting the above technical solutions, both studs and bolts can achieve the anchoring function required by the anchor.

[0030] Secondly, the construction method for a steel-concrete composite beam structure that is first simply supported and then continuous, provided in this application, adopts the following technical solution:

[0031] A construction method for a steel-concrete composite beam structure consisting of a simply supported and then continuous section includes the following steps:

[0032] S1: Install the connecting beam onto the steel pipe column;

[0033] S2: Insert the corbel into the connecting beam and align its position;

[0034] S3: Install the concrete formwork base plate between adjacent connecting beams, tie the reinforcing bars, then install the concrete formwork side plate, pour the cast-in-place beam, and cure the concrete until it is completely cured.

[0035] S4: Remove the concrete formwork.

[0036] By adopting the above technical solution, the use of prestressed tendons is eliminated during the construction process, saving the steps required for tendon threading, splicing, tensioning, and grouting. This simplifies the beam structure and the simple-supported to continuous construction process, and greatly shortens the construction period.

[0037] In summary, this application includes at least one of the following beneficial technical effects:

[0038] 1. The length of the corbel is greater than the negative bending moment length of the cast-in-place beam in the span. This allows the corbel to bear the corresponding negative bending moment after the composite beam is converted from a simply supported beam to a continuous beam, avoiding direct tension on the cast-in-place concrete. Therefore, there is no need to add prestressing tendons in the continuous beam. Compared with the existing simply supported beam system, this method simplifies the connection between the concrete beam and the steel pipe column and the process of tensioning prestressing. The beam structure and the construction process of converting from simply supported to continuous are simpler, improving construction efficiency and greatly shortening the construction time.

[0039] 2. Anchors used on corbels are used to connect cast-in-place beams. Anchors are embedded in cast-in-place beams, which increases the connection area, enhances the shear strength of the contact surface between the corbel and the cast-in-place beam, and makes the corbel and the surface of the cast-in-place beam more firmly bonded, so that they can better share the load.

[0040] 3. The corbels extending from both sides of the continuous beam are formed by a single corbel inserted into the connecting beam, which makes the connection between the corbel and the connecting beam simpler, and at the same time, the overall integrity of the corbel is better, and the load can be transferred to the connecting beam more evenly.

[0041] 4. The horizontal angle of the corbel can be adjusted before casting the cast-in-place beam, so that the corbel can be better adapted to composite beams with different slopes and orientations, thus increasing the applicability of the corbel;

[0042] 5. The leveling bolts support the brackets. By adjusting the leveling bolts, the horizontal angle of the brackets can be changed. At the same time, the leveling bolts also act as load-bearing components, transferring part of the load of the brackets to the connecting beam below. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this application;

[0044] Figure 2 This is a partial structural diagram of the cast-in-place beam after concealing the concrete layer in Embodiment 1 of this application;

[0045] Figure 3 This is a partial cross-sectional schematic diagram of the connecting beam in Embodiment 1 of this application;

[0046] Figure 4 This is a partial structural diagram of the cast-in-place beam after concealing the concrete layer in Embodiment 2 of this application;

[0047] In the diagram, 100 represents the negative bending moment section; 200 represents the positive bending moment section; 1 is a steel pipe column; 2 is a connecting beam; 21 is a hinged support; 22 is a leveling bolt; 23 is a clamping bolt; 24 is a cavity; 25 is a reinforcing rib; 26 is a positioning ring; 27 is a threaded sleeve; 3 is a corbel; 31 is an anchor; 4 is a cast-in-place beam; 41 is a continuous longitudinal reinforcement; 42 is a span longitudinal reinforcement; and 5 is a bridge bearing. Detailed Implementation

[0048] The following is in conjunction with the appendix Figure 1 -Appendix Figure 4 This application will be described in further detail below.

[0049] Example 1:

[0050] Embodiment 1 of this application proposes a steel-concrete composite beam with a simple-supported-then-continuous structure, referring to... Figures 1-3 This system, used for bridge construction, includes steel pipe columns 1, connecting beams 2, corbels 3, cast-in-place beams 4, bridge bearings 5, and the bridge deck. The steel pipe columns 1 serve as piers and are located on the ground. The bridge bearings 5 ​​are located at the top of the steel pipe columns 1. The connecting beams 2 are mounted on the bridge bearings 5. The corbels 3 are inserted into the connecting beams 2. The cast-in-place beams 4 are cast between the connecting beams 2, with multiple sections of the cast-in-place beams 4 connected at the top of the connecting beams 2. The bridge deck is paved on the top surface of the cast-in-place beams 4.

[0051] Because a bridge constructed using a simple-supported-then-continuous method results in a continuous beam bridge after construction, a negative bending moment segment 100 is generated at the central support point, while the remaining segments are positive bending moment segments 200. The top of the concrete beam corresponding to the negative bending moment segment 100 is under tension, while the bottom of the concrete beam corresponding to the positive bending moment segment 200 is under tension. Since concrete has relatively weak tensile strength, to prevent damage from tensile stress, the conventional construction method involves installing pre-tensioned steel tendons at the top of the concrete beam. These tendons provide compressive prestress to the top of the concrete beam, reducing the tension at the top. In this application, the length of the corbel 3 is greater than the length of the negative bending moment segment 100 on the cast-in-place beam 4. The negative bending moment of the cast-in-place beam 4 is borne by the corbel 3, replacing the direct tension on the concrete of the cast-in-place beam 4. Therefore, there is no need to add prestressing tendons to the continuous beam. Compared with the existing simple-supported-then-continuous beam system, this method simplifies the connection between the concrete beam and the steel pipe column 1, as well as the prestressing process. The beam structure and the simple-supported-to-continuous construction process are simpler, improving construction efficiency and significantly shortening the construction time.

[0052] The steel pipe column 1 is set on the ground and serves as the bridge pier to support the superstructure. The bridge bearing 5 is bolted to the top of the steel pipe column 1 and can be selected according to the span of the bridge. Plate rubber bearings are generally used for medium and small span highway bridges, while pot bearings are generally used for large span continuous beam bridges. This application adopts pot bearings.

[0053] The connecting beam 2 is bolted to the top of the bridge bearing 5. Each connecting beam 2 corresponds to a combination of two sets of steel pipe columns 1 and bridge bearing 5. I-beams and other profiles can be welded between the two steel pipe piles to enhance the overall support stability. The longitudinal section of the connecting beam 2 is hollow T-shaped, with multiple vertical support plates in the middle and two rectangular chambers 24 on both sides for the installation of the brackets 3. Reinforcing ribs 25 are welded between the side walls of the two chambers 24. The longitudinal section of the reinforcing ribs 25 is V-shaped, dividing the space between the two chambers 24 of the connecting beam 2 into multiple triangular cross-section spaces to enhance the overall strength of the connecting beam 2. Hinged supports 21 are welded to the inner bottom wall of the chambers 24 of the connecting beam 2 for hinged connection of the brackets 3. Multiple positioning rings 26 are welded to the top of the connecting beam 2. The positioning rings 26 are used for the passage of the continuous longitudinal reinforcement 41 set in the cast-in-place beam 4. They serve both a positioning function and reduce the use of binding wire, improving the binding efficiency of the continuous longitudinal reinforcement 41. A threaded sleeve 27 is also welded inside the connecting beam 2 to connect the longitudinal reinforcement 42 in the span of the cast-in-place beam 4.

[0054] The corbel 3 is installed within the chamber 24, extending from both ends of the connecting beam 2 along the bridge's extension direction and hinged to the hinge support 21. One corbel 3 is installed in each of the two chambers 24, enhancing load-bearing capacity and improving the overall strength of the bridge. The corbels 3 on both sides of the connecting beam 2 are continuous, which, compared to welding corbels 3 to both ends of the connecting beam 2, allows for more even stress distribution on the corbel 3, reduces welding work, and improves construction efficiency. In this embodiment, the corbel 3 is an I-beam. Multiple anchors 31 are welded to the flanges and web of the corbel 3. These anchors 31 connect the corbel 3 to the cast-in-place beam 4. Embedded in the cast-in-place beam 4, the anchors 31 increase the connection area, enhance the shear strength of the contact surface between the corbel 3 and the cast-in-place beam 4, and ensure a stronger bond between the corbel 3 and the surface of the cast-in-place beam 4, allowing for better shared stress distribution. The anchors 31 can be either studs or bolts; in this embodiment, the anchors 31 are studs, welded evenly spaced onto the corbel 3.

[0055] A leveling bolt 22 is threaded onto the bottom wall of the connecting beam 2. The threaded end of the leveling bolt 22 extends upward into the cavity 24 to support the corbel 3. Multiple leveling bolts 22 are installed on both sides of the hinge axis of the corbel 3. By tightening the leveling bolts 22, the corbel 3 can be adjusted to different angles and supported, allowing the corbel 3 to adapt to the bridge's orientation and increasing its applicability. Simultaneously, the leveling bolts 22 also act as load-bearing components, transferring a portion of the load from the corbel 3 to the connecting beam 2 below. A clamping bolt 23 is threaded onto the top wall of the connecting beam 2. The threaded end of the clamping bolt 23 extends downward into the cavity 24 and abuts against the top of the corbel 3. The leveling bolts 22 and clamping bolts 23 together fix the position of the corbel 3 within the connecting beam 2, preventing the corbel 3 from deviating from its position during the later pouring of the cast-in-place beam 4.

[0056] The construction method steps for bridges in Embodiment 1 of this application are as follows:

[0057] Assemble the connecting beam 2 and the bracket 3, and insert the hinge shaft to hinge the bracket 3 and the connecting beam 2.

[0058] Install steel pipe columns 1 according to the predetermined positions, ensuring the verticality of the steel pipe columns 1, and erect a construction platform. Set sand cylinder supports at the top of the steel pipe columns 1, with four sand cylinder supports at the top of each steel pipe column 1, ensuring that the supporting surfaces of each sand cylinder support are flush.

[0059] Using a crane, the connecting beam 2 and the corbel 3 are lifted as a whole. After aligning the installation position of the connecting beam 2, it is hoisted onto the sand cylinder support. The adjusting bolts are adjusted to support the corbel 3 according to the direction of the bridge. After the support is completed, the clamping bolt 23 is tightened. The clamping bolt 23 and the support bolt together fix the corbel 3 firmly.

[0060] Temporary support frames are erected in the span, and concrete formwork base plates for cast-in-place beam 4 are installed. The longitudinal reinforcement 41 is passed through positioning ring 26 and installed on connecting beam 2. The longitudinal reinforcement 42 in the span is installed on connecting beam 2 through threaded sleeve 27. The remaining reinforcement is tied, and then the concrete formwork side plates for cast-in-place beam 4 are installed. Cast-in-place beam 4 is poured, and concrete is poured into the interior of connecting beam 2 at the same time to fill the gap between corbel 3 and connecting beam 2. The top concrete covers the top of connecting beam 2.

[0061] Cure the concrete of cast-in-place beam 4 until it is completely hardened.

[0062] Remove the concrete formwork and temporary support frame, and install bridge bearings 5 ​​at the top of each steel pipe column 1.

[0063] Gradually remove the sand from each sand cylinder, ensuring the amount of sand removed is even. As the sand cylinders are gradually removed, the connecting beam 2 is placed onto the bridge support 5. Install bolts to connect the bridge support 5 and the connecting beam 2.

[0064] The bridge deck was laid, drainage pipes and guardrails were installed, and the bridge construction was completed.

[0065] Example 2:

[0066] Reference Figure 4 The difference between Embodiment 2 and Embodiment 1 is that the connecting beam 2 is provided with only one steel pipe column 1, and the connecting beam 2 and the steel pipe column 1 are welded; the longitudinal section of the connecting beam 2 is a hollow rectangle, with only one chamber 24, and a corbel 3 is provided in the chamber 24; Embodiment 2 of this application can be used for bridges as well as other buildings.

[0067] Embodiment 2 of this application also proposes a construction method for a steel-concrete composite beam that is first simply supported and then continuous, including the following steps:

[0068] Install steel pipe column 1 according to the predetermined position, ensure the verticality of steel pipe column 1, and erect a construction platform.

[0069] The connecting beam 2 is hoisted to the top of the steel pipe column 1. After aligning the direction, temporary supports are installed, and the connecting beam 2 is welded to the top of the steel pipe column 1.

[0070] Hoist the bracket 3, insert it into the connecting beam 2 and align its position, then install the hinge shaft to hinge the bracket 3 to the connecting beam 2.

[0071] Adjust the support bracket 3 with adjusting bolts according to the direction of the composite beam. After the support is completed, tighten the clamping bolt 23. The clamping bolt 23 and the support bolt together fix the bracket 3 firmly.

[0072] Temporary support frames are erected between adjacent steel pipe columns 1, and concrete formwork base plates for cast-in-place beam 4 are installed. The longitudinal reinforcement 41 is passed through positioning ring 26 and installed on connecting beam 2. The longitudinal reinforcement 42 between spans is installed on connecting beam 2 through threaded sleeve 27. The remaining reinforcement is tied, and then the concrete formwork side plates for cast-in-place beam 4 are installed. Cast-in-place beam 4 is poured, and concrete is poured into the interior of connecting beam 2 at the same time to fill the gap between corbel 3 and connecting beam 2. The top concrete covers the top of connecting beam 2.

[0073] Curing of the concrete in cast-in-place beam 4 until it is completely hardened completes the construction.

[0074] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A steel-concrete structure type simply supported and then continuous composite beam, characterized by, include: Steel pipe columns (1) are provided in multiple locations along the direction of the composite beam; The connecting beam (2) is set at the top of the steel pipe column (1); The corbel (3) is connected to the connecting beam (2) and extends away from the connecting beam (2) along the direction of the composite beam. Multiple anchors (31) are fixedly connected to the outer wall. Cast-in-place beam (4) is connected between two adjacent connecting beams (2); The corbel (3) is embedded in the cast-in-place beam (4), and the length of the corbel (3) is greater than the negative bending moment length of the cast-in-place beam (4) in the span. The corbel (3) is inserted into the connecting beam (2), and its two ends protrude from both sides of the connecting beam (2); The inner bottom wall of the connecting beam (2) is provided with a hinge support (21), and the bracket (3) is hinged to the hinge support (21).

2. The steel-concrete composite beam with a simple-supported-then-continuous structure according to claim 1, characterized in that, The inner bottom wall of the connecting beam (2) is threaded with multiple leveling bolts (22) that abut against the bracket (3).

3. The steel-concrete composite beam with a simple-supported-then-continuous structure according to claim 2, characterized in that, The inner top wall of the connecting beam (2) is threaded with multiple clamping bolts (23) that abut against the bracket (3).

4. A steel-concrete composite beam with a simple-supported-then-continuous structure according to claim 1, characterized in that, The cast-in-place beam (4) is provided with a continuous longitudinal reinforcement (41), and the connecting beam (2) is fixedly connected with a positioning ring (26) for the continuous longitudinal reinforcement (41) to pass through.

5. A steel-concrete composite beam with a simple-supported-then-continuous structure according to claim 4, characterized in that, The cast-in-place beam (4) is provided with longitudinal reinforcement bars (42) between spans, and the connecting beam (2) is fixedly connected with a threaded sleeve (27) for connecting the longitudinal reinforcement bars (42) between spans.

6. A steel-concrete composite beam with a simple-supported-then-continuous structure according to claim 1, characterized in that, The anchor (31) is either a stud or a screw.

7. A steel-concrete composite beam with a simple-supported-then-continuous structure according to claim 1, characterized in that, The connecting beam (2) is provided with multiple chambers (24) through which the cow leg (3) passes, and reinforcing ribs (25) are provided between the side walls of adjacent chambers (24).

8. The construction method of a steel-concrete composite beam with a simple-supported-then-continuous structure as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Install the connecting beam (2) on the steel pipe column (1); S2: Insert the corbel (3) into the connecting beam (2) and align its position; S3: Install the concrete formwork base plate between adjacent connecting beams (2), tie the reinforcing bars, then install the concrete formwork side plate, pour the cast-in-place beam (4), and cure the concrete until it is completely cured; S4: Remove the concrete formwork.

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