Connecting structure of newly-added steel longitudinal beam and existing concrete cross beam and construction method

Abstract

The invention relates to the technical field of bridge engineering, and provides a newly-added steel longitudinal beam and existing concrete cross beam connecting structure and a construction method.The newly-added steel longitudinal beam and existing concrete cross beam connecting structure comprises a cross beam and a longitudinal beam, the cross beam is sleeved with a steel plate frame, the two longitudinal ends of the steel plate frame are each provided with a pressure bearing box, and the steel plate frame is fixed to the cross beam through chemical bolts and bolt connecting pairs; the bolt connecting pair horizontally penetrates through the pressure-bearing box and the steel plate frame, the pressure-bearing box longitudinally and horizontally extends to form a connecting part, the connecting part is connected with the longitudinal beam through the clamping plate and the bolt, and the longitudinal beam and the cross beam are connected through the steel plate frame and the pressure-bearing box, so that the integrity of the bridge floor system is enhanced, and the problem that the cross beams of a traditional fifth-class bridge floor system are lack of longitudinal connection is solved. The safety degree and reliability of structural connection are improved, the steel plate frame and the cross beam are firmly fixed through the bolt connecting pair and the chemical bolts, and epoxy mortar is filled between the steel plate frame and the cross beam and in the pressure bearing box, so that it is ensured that loads can be evenly and effectively transmitted, and the stress concentration phenomenon is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge engineering, and in particular to a connection structure and a construction method of a newly added steel longitudinal beam and an existing concrete cross beam. Background Art

[0002] The design of the deck system of a steel tube concrete arch bridge directly affects the integrity, robustness and performance of the bridge. According to the structural characteristics, the deck system can be divided into five categories, with integrity and robustness decreasing in turn. Early mid-under arch bridges often adopted the fifth type of deck system, that is, the crossbeam was suspended by a hanger, and the bridge deck was directly supported on the crossbeam without stiffening longitudinal beams. This system is a statically determinate structure with a single force transmission path. The crossbeam is subjected to large forces and lacks longitudinal connection, resulting in large deformation and vibration of the bridge deck and poor risk resistance. Once the hanger breaks, it may cause partial collapse of the bridge deck, and the integrity and robustness are both poor.

[0003] In order to reduce such accidents, the Technical Specification for Steel Tube Concrete Arch Bridges (GB 50923-2013) promulgated in 2013 requires that the suspended bridge deck system of the mid-under arch bridge should adopt an integral structure, set up stiffened longitudinal beams, and have the ability to prevent the beam from falling after the slings at both ends of a beam fail. However, a large number of early-built bridges still use the fifth type of bridge deck system, which is in urgent need of reinforcement and reconstruction. At present, in order to control costs, the reinforcement plan generally adopts the addition of steel longitudinal beams to transform the bridge deck system from the fifth type of bridge deck system to the fourth type of bridge deck system. However, the connection reliability of the steel longitudinal beam and the concrete cross beam in the existing technology is poor, and it is difficult to ensure the overall force and durability of the structure. Summary of the invention

[0004] The purpose of the present invention is to provide a connection structure and construction method for a newly added steel longitudinal beam and an existing concrete cross beam, which solves the problem in the prior art that the connection reliability between the steel longitudinal beam and the concrete cross beam is poor and it is difficult to ensure the overall stress and durability of the structure.

[0005] The present invention is achieved through the following technical scheme: a connection structure of a newly added steel longitudinal beam and an existing concrete cross beam, including a cross beam and a longitudinal beam, a steel plate frame is sleeved on the cross beam, pressure boxes are respectively arranged at both longitudinal ends of the steel plate frame, the steel plate frame is fixed to the cross beam by chemical bolts and a bolt connection pair, the bolt connection pair horizontally penetrates the pressure box and the steel plate frame, the pressure box has a connecting part extending outward longitudinally and horizontally, and the connecting part is connected to the longitudinal beam by a clamping plate and bolts.

[0006] Furthermore, epoxy mortar is filled between the steel plate frame and the cross beam as well as in the pressure box.

[0007] Furthermore, the longitudinal beam is made of I-beam.

[0008] Furthermore, the connection part is an I-beam that is flush with the longitudinal beam, and the clamping plates respectively clamp the connection part and the web and bottom plate of the longitudinal beam.

[0009] Furthermore, a toggle plate is provided between the steel plate frame and the connecting portion.

[0010] Furthermore, a pressure-bearing pipe bushing sleeved on the bolt connection pair is arranged in the pressure-bearing box.

[0011] Furthermore, the bolt connection pair adopts a screw made of 45 steel.

[0012] A construction method comprises the following steps:

[0013] Step 1: Roughen the installation position of the steel plate frame on the crossbeam, and drill reserved holes on the crossbeam for the insertion of chemical bolts and bolt connection pairs;

[0014] Step 2: Measure the size of the existing beam, prefabricate the steel plate frame, and pour epoxy mortar into the pressure box. The inner edge of the steel plate frame is larger than the outer contour of the longitudinal section of the beam;

[0015] Step 3: Position and install the steel plate frame, set up templates on both sides of the steel plate frame, pour epoxy mortar into the steel plate frame, and then install chemical bolts and bolt connection pairs;

[0016] Step 4: Hoist and position the longitudinal beam, connect the longitudinal beam to the connecting part, and complete the construction.

[0017] Furthermore, a pre-tightening force is applied to the bolt connection pair.

[0018] Furthermore, the depth of the chemical bolt inserted into the crossbeam is not less than 10 cm.

[0019] The present invention has at least the following advantages and beneficial effects:

[0020] (1) The longitudinal beams and transverse beams are connected by steel plate frames and pressure boxes, which enhances the integrity of the bridge deck system, improves the problem of lack of longitudinal connection between transverse beams in the traditional fifth-class bridge deck system, and improves the safety and reliability of the structural connection.

[0021] (2) The steel plate frame and the beam are firmly fixed by bolt connection pairs and chemical bolts, and epoxy mortar is filled between the steel plate frame and the beam and in the pressure box to ensure that the load can be transmitted evenly and effectively, reduce stress concentration, ensure the integrity and rigidity of the connection node, and improve the bonding strength and durability of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A front view of a connection structure between a newly added steel longitudinal beam and an existing concrete cross beam provided by the present invention.

[0023] Figure 2 A side view of a connection structure between a newly added steel longitudinal beam and an existing concrete cross beam provided by the present invention.

[0024] Figure 3 A flow chart of a construction method for a connection structure between a newly added steel longitudinal beam and an existing concrete cross beam provided by the present invention.

[0025] Figure numerals: 1-cross beam, 2-steel plate frame, 3-pressure box, 31-connecting part, 32-pressure pipe bushing, 4-chemical bolt, 5-bolt connection pair, 6-clamp plate, 7-longitudinal beam, 8-elbow plate. DETAILED DESCRIPTION

[0026] The following is a specific implementation method in conjunction with the accompanying drawings.

[0027] Example

[0028] like Figure 1 , Figure 2 As shown, in this embodiment, a connection structure of a newly added steel longitudinal beam and an existing concrete cross beam is mainly disclosed, including a cross beam 1 and a longitudinal beam 7. A steel plate frame 2 is sleeved on the cross beam 1. Pressure boxes 3 are respectively arranged at both ends of the steel plate frame 2 in the longitudinal direction. The steel plate frame 2 is fixed to the cross beam 1 by chemical bolts 4 and bolt connection pairs 5. The bolt connection pairs 5 horizontally penetrate the pressure box 3 and the steel plate frame 2. The pressure box 3 has a connection portion 31 extending outward in the longitudinal direction. The connection portion 31 is connected to the longitudinal beam 7 by a clamping plate 6 and bolts. Specifically, the cross beam 1 is an existing steel tube concrete arch bridge suspender cross beam 1. The steel plate frame 2 is a frame structure formed by welding four steel plates, and the pressure box 3 is a box structure welded to the side of the steel plate frame 2, which is used to bear and disperse the tension of the bolt connection pair 5. The cross-sectional form of the connection portion 31 extending outward from the pressure box 3 is consistent with the longitudinal beam 7. The bolt connection pair 5 and the chemical bolt 4 firmly fix the steel plate frame 2 and the cross beam 1 to ensure that the load can be effectively transmitted. The longitudinal beam 7 is connected to the cross beam 1 through the steel plate frame 2 and the pressure box 3, which enhances the integrity of the bridge deck system and improves the problem of lack of longitudinal connection between the cross beams 1 of the traditional fifth type bridge deck system.

[0029] Furthermore, in a specific implementation, epoxy mortar is filled between the steel plate frame 2 and the cross beam 1 and inside the pressure box 3 provided in the embodiment of the present invention. Specifically, epoxy mortar has excellent corrosion resistance and anti-aging properties, which prolongs the service life of the connection structure. Epoxy mortar fills the gap between the steel plate frame 2 and the cross beam 1, improves the bonding strength between the two, makes the contact surface between the steel plate frame 2 and the cross beam 1 more uniform, reduces stress concentration, and ensures uniform load transfer. Filling the pressure box 3 with epoxy mortar ensures the integrity and rigidity of the pressure box 3 and improves the durability of the structure.

[0030] Furthermore, in the specific implementation, the longitudinal beam 7 provided in the embodiment of the present invention adopts I-beam. I-beam has high bending and shear strength, can effectively bear the bridge deck load, reduce bridge deck deformation and vibration, has a simple structure, only needs three steel plates to be welded, its weld is straight, welding production quality is easy to ensure, making the whole connection structure relatively simple, and convenient for operation period management and maintenance.

[0031] Preferably, the connection part 31 is an I-beam that is flush with the longitudinal beam 7, and the plywood 6 clamps the connection part 31 and the web and bottom plate of the longitudinal beam 7, respectively. Specifically, the connection part 31 is flush with the longitudinal beam 7, which reduces installation errors and improves construction quality. The plywood 6 clamps the connection part 31 and the web and bottom plate of the longitudinal beam 7, thereby ensuring the firmness of the connection and the continuity of force transmission. In addition, the top plate of the connection part 31 and the top plate of the longitudinal beam 7 can be connected by welding. When the longitudinal beam 7 needs to be replaced at a later stage, the bolts and plywood 6 can be removed to achieve separation more easily.

[0032] Furthermore, in a specific implementation, a toggle plate 8 is provided between the steel plate frame 2 and the connection part 31 provided in the embodiment of the present invention, which can effectively disperse the stress at the connection part 31, improve the local stiffness and deformation resistance, reduce the stress concentration at the connection part 31, and enhance the fatigue resistance of the structure.

[0033] Furthermore, in a specific implementation, a pressure pipe bushing 32 sleeved on the bolt connection pair 5 is provided in the pressure box 3 provided in the embodiment of the present invention, so that the threaded connection pair passes through the pressure box 3, thereby reducing the wear and corrosion of the bolt connection pair 5 and extending its service life.

[0034] Furthermore, in a specific implementation, the bolt connection pair 5 provided in the embodiment of the present invention uses a screw made of 45 steel, which has high strength, toughness and fatigue resistance, can withstand a large preload and load, and ensure the reliability of the connection.

[0035] like Figure 3 As shown, in this embodiment, a construction method is also disclosed, comprising the following steps:

[0036] Step 1: roughen the installation position of the steel plate frame 2 on the beam 1, and drill reserved holes on the beam 1 for the insertion of chemical bolts 4 and bolt connection pairs 5; during the specific construction, it is first necessary to remove the sidewalk slabs along the line where the longitudinal beam 7 is to be installed, and then pre-treat the beam 1 before installing the longitudinal beam 7. After the pre-treatment is completed, the beam 1 needs to be cleaned and dried.

[0037] Step 2: measure the size of the existing beam 1, prefabricate the steel plate frame 2, and pour epoxy mortar in the pressure box 3. The inner edge size of the steel plate frame 2 is larger than the outer contour size of the longitudinal section of the beam 1. Specifically, through factory prefabrication, the steel plate frame 2 and the pressure box 3 are welded together, and the longitudinal beam 7 is welded in advance, which improves the construction accuracy and the integrity of the structure. The modular design is adopted, which is convenient for on-site installation and shortens the construction period.

[0038] Step 3: Position and install the steel plate frame 2, and set up templates on both sides of the steel plate frame 2, pour epoxy mortar into the steel plate frame 2, and then install chemical bolts 4 and bolt connection pairs 5 to ensure a tight connection between the steel plate frame 2 and the beam 1.

[0039] Step 4: hoist and position the longitudinal beam 7, connect the longitudinal beam 7 to the connecting portion 31, reinstall the sidewalk slab, and complete the construction.

[0040] It should be noted that the failure modes of the connection structure between the longitudinal beam 7 and the cross beam 1 in the present invention are: failure of the prestressing of the bolt connection pair 5, breaking of the bolt connection pair 5, breaking of the chemical bolt 4, failure of the bonding force of the epoxy mortar between the steel plate frame 2 and the cross beam 1, tearing of the weld of the steel plate frame 2, and finally failure of the connection structure. The safety and reliability of the structural connection are high.

[0041] Furthermore, in a specific implementation, the bolt connection pair 5 provided in the embodiment of the present invention is applied with a pre-tightening force, which can reduce the risk of loosening of the bolt connection pair 5, improve the overall rigidity of the connection structure, reduce the stress amplitude of the bolt connection pair 5 under the action of dynamic load, extend the service life, make the connection part 31 more tightly, and ensure that the load can be effectively transmitted.

[0042] Furthermore, in a specific implementation, the depth of the chemical bolt 4 provided in the embodiment of the present invention inserted into the crossbeam 1 is not less than 10 cm, thereby ensuring the bonding strength between the chemical bolt 4 and the crossbeam 1 and enhancing the reliability of the connection.

Claims

1. A connection structure of a newly added steel longitudinal beam and an existing concrete cross beam, comprising a cross beam (1) and a longitudinal beam (7), characterized in that: A steel plate frame (2) is sleeved on the cross beam (1), and pressure boxes (3) are respectively arranged at the longitudinal ends of the steel plate frame (2). The steel plate frame (2) is fixed to the cross beam (1) by chemical bolts (4) and bolt connection pairs (5), and the bolt connection pairs (5) horizontally penetrate the pressure box (3) and the steel plate frame (2). The pressure box (3) has a connecting portion (31) extending outward longitudinally and horizontally, and the connecting portion (31) is connected to the longitudinal beam (7) by a clamping plate (6) and bolts.

2. The connection structure of a newly added steel longitudinal beam and an existing concrete cross beam according to claim 1 is characterized in that: Epoxy mortar is filled between the steel plate frame (2) and the crossbeam (1) as well as inside the pressure box (3).

3. The connection structure of a newly added steel longitudinal beam and an existing concrete cross beam according to claim 1 is characterized in that: The longitudinal beam (7) is made of I-beam.

4. The connection structure of the newly added steel longitudinal beam and the existing concrete cross beam according to claim 3 is characterized in that: The connecting portion (31) is an I-beam that is flush with the longitudinal beam (7), and the clamping plate (6) respectively clamps the web and bottom plate of the connecting portion (31) and the longitudinal beam (7).

5. The connection structure of a newly added steel longitudinal beam and an existing concrete cross beam according to claim 1 is characterized in that: A toggle plate (8) is provided between the steel plate frame (2) and the connecting portion (31).

6. The connection structure of a newly added steel longitudinal beam and an existing concrete cross beam according to claim 1, characterized in that: The pressure box (3) is provided with a pressure pipe bushing (32) sleeved on the bolt connection pair (5).

7. The connection structure of a newly added steel longitudinal beam and an existing concrete cross beam according to claim 1 is characterized in that: The bolt connection pair (5) uses a screw made of 45# steel.

8. A construction method for a connection structure of a newly added steel longitudinal beam and an existing concrete cross beam based on any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: roughening the installation position of the steel plate frame (2) on the crossbeam (1), and drilling reserved holes on the crossbeam (1) for inserting the chemical bolts (4) and the bolt connection pair (5); Step 2: Measure the size of the existing crossbeam (1), prefabricate the steel plate frame (2), and pour epoxy mortar into the pressure box (3), wherein the inner edge size of the steel plate frame (2) is larger than the outer contour size of the longitudinal section of the crossbeam (1); Step 3: Position and install the steel plate frame (2), set up templates on both sides of the steel plate frame (2), pour epoxy mortar into the steel plate frame (2), and then install the chemical bolts (4) and the bolt connection pair (5); Step 4: hoist and position the longitudinal beam (7), connect the longitudinal beam (7) to the connecting portion (31), and complete the construction.

9. The construction method according to claim 8, characterized in that: The bolt connection pair (5) is applied with a pre-tightening force.

10. The construction method according to claim 8, characterized in that: The chemical bolt (4) is inserted into the crossbeam (1) to a depth of not less than 10 cm.

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