A method for closure construction of large-span cap beam with few supports under an existing bridge

Abstract

The present application discloses a method for closure construction of a large-span cap beam with few supports under an existing bridge, which divides the crossbeam installation area into a restricted area and an unrestricted area, installs an outer cover plate on the top of the pier column, pours concrete on the inner side of the outer cover plate, and then installs a support structure and a first jack on the outer side of the outer cover plate, builds a vertical support in the open area, and installs a traction assembly on the top of the vertical support, lifts the crossbeam to the top of one of the pier columns in the restricted area, the first jack on the top of the pier column supports the bottom of the crossbeam, and the traction assembly pulls the crossbeam until the crossbeam is shifted to the top of the two pier columns in the restricted area, and the first jack shrinks downward to place the crossbeam on the cast-in-place section of the two pier columns; the crossbeam is lifted to the top of the pier column in the open area, and the crossbeams in the restricted area and the open area are closed. The present application has the effect of reducing the occupation of the lower road surface.

Description

Technical Field

[0001] The present application relates to the field of bridge construction, and in particular to a construction method for closing a large-span cap beam under an existing bridge with few supports. Background Art

[0002] As urban transportation is continuously optimized and upgraded, new lines are increasingly intersecting with existing lines in both plane and three-dimensional layouts. Portal piers and beams are components of bridge structures, mostly in the form of steel structures. Portal piers and beams are often located between the lower road surface and the upper operating elevated road. Affected by the existing elevated road above, they cannot be directly hoisted to the actual bridge location.

[0003] In the related art, a support system for supporting the beam is formed by building a support around each pier column and installing a jack on the top of the support. The beam is then hoisted onto the jack on the top of the support. The beam is then moved horizontally into place by dragging and lowered to the pier support by the jack. The support bears the load generated by the hoisting and dragging construction to reduce the probability of overturning of the pier column.

[0004] Regarding the above-mentioned related technologies, there are the following defects: most of the brackets occupy the lower road surface, affecting the normal passage of vehicles, so there is still room for improvement. Summary of the invention

[0005] In order to reduce the occupation of the lower road surface, the present application provides a construction method for the joint of a large-span cap beam under an existing bridge with few supports.

[0006] The present application provides a method for closure construction of a large-span cap beam with few supports under an existing bridge, which adopts the following technical solution:

[0007] A construction method for closing a large-span cap beam with few supports under an existing bridge comprises the following steps:

[0008] S1: Divide the beam installation area into a restricted area and an unrestricted area, wherein the area where the beam cannot be directly hoisted into place is the restricted area, and the area where the beam can be directly hoisted into place is the open area, install an outer cover plate on the top of the pier column, pour concrete on the inner side of the outer cover plate to form a cast-in-place section on the top of the pier column, then install a supporting structure and the first jack on the outer side of the outer cover plate, build a set of vertical brackets in the open area, and install a traction assembly on the top of the vertical brackets;

[0009] S2: hoist the beam to the top of one of the bridge pier columns in the restricted area, the first jack on the top of the bridge pier column supports the bottom of the beam, and the traction assembly pulls the beam until the beam moves to the top of the two bridge pier columns in the restricted area, and the first jack retracts downward to place the beam on the cast-in-place section on the top of the two bridge pier columns;

[0010] S3: Lift the beams to the top of the pier columns in the open area, and then close the beams in the restricted area and the beams in the open area.

[0011] By adopting the above technical solution, casting on the top of the pier column to form a casting section, and installing the supporting structure and the first jack, a new beam support system is formed, thereby replacing the bracket. Only a set of vertical brackets are built in the open area as the supporting structure of the traction assembly, which is beneficial to reducing the occupied area of ​​the lower road surface. The load generated by the traction operation is transmitted to the vertical brackets, which is beneficial to reducing the probability of overturning of the pier column.

[0012] Preferably, in S1, a plurality of steel rods horizontally penetrate two mutually opposite side walls of the outer package plate, and the supporting structure is a steel corbel, which is locked at one end of the steel rod extending out of the outer side of the outer package plate.

[0013] By adopting the above technical solution, the main body of the steel rod is cast in the cast-in-place section, which can improve the bonding degree between the steel rod and the cast-in-place section. At the same time, the steel rod is used as an embedded part, and the steel corbel is locked at the end of the steel rod extending out of the outer panel, reserving the installation position of the supporting structure to facilitate the installation and fixation of the steel corbel.

[0014] Preferably, a pulley is installed on the top of the first jack.

[0015] By adopting the above technical solution, when the beam is placed on the jack, it directly contacts the pulley on the top of the first jack to reduce the friction generated when the beam moves horizontally, which is beneficial to improving the overturning problem of the pier column during the dragging process.

[0016] Preferably, the traction assembly is a winch, and the traction rope of the winch is connected to the middle position of the bottom of the beam.

[0017] By adopting the above technical solution, the connection point of the traction rope is set directly below the center of gravity of the beam to improve the situation where the beam swings down at a large angle when being pulled, which is beneficial to improving the movement stability of the beam during the pulling process.

[0018] Preferably, a guide wheel is installed on a steel bracket of a pier column adjacent to the vertical support, and the traction rope of the winch abuts against the surface of the guide wheel.

[0019] By adopting the above technical solution, the guide wheel guides the traction rope, so that the traction direction of the traction rope remains stable, which is beneficial to improving the movement stability of the beam during the process of pulling the beam.

[0020] Preferably, in S3, a second jack is installed on the top of the vertical support, and the second jack and the first jack in the open area constitute a support system for the beam.

[0021] By adopting the above technical solution, the vertical bracket cooperates with the bridge pier columns in the open area to form a support system for the beams in the open area, thereby facilitating the positioning of the beams in the open area.

[0022] Preferably, the position of the winch is lower than the upper surface of the pier column.

[0023] By adopting the above technical solution, the installation height of the winch is lower than the upper surface of the pier column, so there is no need to disassemble the winch when installing the beam in the open area, which facilitates the installation of the beam in the open area.

[0024] Preferably, in S3, the traction rope of the winch is connected to the bottom of the beam in the open area. After the beam is placed on the first jack and the second jack, the winch is used to pull the beam to fine-tune the distance between the two beams until they are assembled together, and finally the closing construction is carried out.

[0025] By adopting the above technical solution, after the beam in the open area is in place, the winch is used again to pull it so as to fine-tune the position of the beam, so that the two beams fit better and facilitate the closing construction of the two beams.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] 1. By first pouring a pouring section on the top of the pier column, and installing the support structure and the first jack to form a new beam support system, the bracket is replaced, and only a set of vertical brackets are built in the open area as the support structure of the traction assembly, which is conducive to reducing the occupied area of ​​the lower road surface. The load generated by the traction operation is transmitted to the vertical bracket, which is conducive to reducing the probability of the pier column overturning;

[0028] 2. The main body of the steel rod is cast in the cast-in-place section by passing the steel rod through the outer plate, which can improve the bonding between the steel rod and the cast-in-place section. At the same time, the steel rod is used as an embedded part, and the steel corbel is locked at the end of the steel rod extending out of the outer plate, and the installation position of the supporting structure is reserved, which is convenient for the installation and fixation of the steel corbel;

[0029] 3. By installing a guide wheel on a steel bullneck of a pier column adjacent to the vertical support, the guide wheel guides the traction rope, so that the traction direction of the traction rope remains stable, which is beneficial to improving the movement stability of the beam during the pulling process of the beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the state of a beam in a restricted area after it is in place in a construction method for closing a large-span cap beam of an existing bridge with few supports in an embodiment of the present application.

[0031] Figure 2yes Figure 1 A magnified schematic diagram of center A.

[0032] Figure 3 It is a schematic diagram of the connection between the outer cladding plate and the steel rods in a method for jointing a large-span cap beam with few supports under an existing bridge in an embodiment of the present application.

[0033] Figure 4 yes Figure 3 A magnified schematic diagram of point B in the middle.

[0034] Figure 5 It is a schematic diagram of the state of the crossbeam in the open area after it is in place in a construction method for closing a large-span cap beam with few supports under an existing bridge in an embodiment of the present application.

[0035] Explanation of the reference numerals in the accompanying drawings: 1. Existing elevated structure; 2. Pier column; 21. Steel corbel; 22. First jack; 23. Pulley; 24. Guide wheel; 25. Cast-in-place section; 26. Outer plate; 27. Steel rod; 3. Vertical support; 4. Crossbeam; 5. Winch; 51. Traction rope; 6. Second jack; 7. Restricted area; 8. Open area. DETAILED DESCRIPTION

[0036] The following is combined with Figure 1-5 This application is described in further detail.

[0037] The present application embodiment discloses a method for closure construction of a large-span cap beam with few supports under an existing bridge. Figure 1 and Figure 2 , including the following steps:

[0038] S1: The installation area of ​​the beam 4 is divided into a restricted area and an unrestricted area 7, wherein the area where the beam 4 cannot be directly hoisted into place is the restricted area 7, and the area where the beam 4 can be directly hoisted into place is the open area 8. The beam 4 is a steel structure.

[0039] An outer covering plate 26 is installed on the top of the pier column 2 to form a casting template with a closed periphery. Then concrete is poured into the inner side of the outer covering plate 26 to form a cast-in-place section 25 on the top of the pier column 2.

[0040] Reference Figure 3 and Figure 4 Before pouring concrete, a number of steel rods 27 are horizontally passed through two mutually opposite side walls of the outer cover plate 26, wherein the length of the steel rods 27 is consistent with the length direction of the cross beam 4. Both ends of the steel rods 27 protrude outside the outer cover plate 26, and the exposed steel bars are tied and fixed to the steel rods 27 to improve the connection stability of the pier column 2, the steel rods 27 and the outer cover plate 26. The main body of the steel rods 27 is cast in the cast-in-place section 25, which can improve the bonding degree between the steel rods 27 and the cast-in-place section 25.

[0041] Then, the supporting structure and the first jack 22 are installed outside the outer plate 26, wherein the supporting structure is a steel corbel 21, the end of the steel rod 27 protruding outside the outer plate 26 passes through the mounting hole of the steel corbel 21, and then the steel corbel 21 is locked outside the outer plate 26. The steel rod 27 is used as an embedded part, and the steel corbel 21 is locked to the end of the steel rod 27 protruding outside the outer plate 26, and the installation position of the steel corbel 21 is reserved, so as to facilitate the installation and fixation of the steel corbel 21.

[0042] Then the first jack 22 is vertically installed and fixed in the steel bull leg 21. The piston rod of the first jack 22 vertically penetrates the surface of the steel bull leg 21. The upper surface of the steel bull leg 21 is lower than the upper surface of the pier column 2. A set of pulleys 23 is installed on the top of the first jack 22 to reduce the friction generated when the beam 4 translates, which is beneficial to improve the overturning problem of the pier column 2 during the dragging process.

[0043] A set of vertical supports 3 are built in the open area 8, and the upper surface of the vertical supports 3 is lower than the upper surface of the pier column 2. A traction assembly is installed on the top of the vertical supports 3, wherein the traction assembly is a winch 5, and the position of the winch 5 is also lower than the upper surface of the pier column 2. The traction rope 51 of the winch 5 is connected to the midpoint of the bottom of the beam 4 in the restricted area 7. Therefore, the connection point of the traction rope 51 is set just below the center of gravity of the beam 4, which can improve the situation that the beam 4 swings down at a large angle when being pulled, and is conducive to improving the movement stability of the beam 4 during the pulling process.

[0044] Reference Figure 1 and Figure 2 A guide wheel 24 is installed on the upper surface of a steel corbel 21 of a pier column 2 adjacent to the vertical support 3 in the restricted area 7, and the guide wheel 24 is supported by a mounting frame. The guide wheel 24 is arranged side by side with the pulley 23, and the guide wheel 24 is located at a position lower than the pulley 23. The traction rope 51 of the winch 5 passes through the guide wheel 24 and abuts against the upper surface of the guide wheel 24. The guide wheel 24 guides the traction rope 51, so that the traction direction of the traction rope 51 remains stable, which is conducive to improving the movement stability of the cross beam 4 during the pulling process of the cross beam 4.

[0045] S2: When installing the cross beam 4, the crane lifts the cross beam 4 to the top of one of the bridge pier columns 2 in the restricted area 7. The lifting point of the crane is located directly above the center of gravity of the cross beam 4. The cross beam 4 is slowly lowered so that the bottom of the cross beam 4 abuts against the surface of the pulley 23. The first jack 22 on the top of the bridge pier column 2 supports the bottom of the cross beam 4. Then the winch 5 is started, and the winch 5 reels the traction rope 51 to steadily pull the cross beam 4 until the cross beam 4 is shifted to the top of the two bridge pier columns 2 in the restricted area 7. Then the first jack 22 is retracted downward to make the height of the pulley 23 lower than the bridge pier column 2. At the same time, the cross beam 4 is placed on the cast-in-place section 25 on the top of the two bridge pier columns 2. At this time, the center of gravity of the cross beam 4 is below the existing elevated 1.

[0046] By first casting on the top of the pier column 2 to form a casting section, and using the steel corbel 21 and the first jack 22 to form a new beam 4 support system, thereby replacing the bracket, only a set of vertical brackets 3 are built in the open area 8 as the support structure of the traction assembly, which is beneficial to reducing the occupied area of ​​the lower road surface. The load generated by the traction operation is transmitted to the vertical brackets 3, which is beneficial to reducing the probability of overturning of the pier column 2.

[0047] S3: Reference Figure 5 After the cross beam 4 of the restricted area 7 is in place, untie the connection between the traction rope 51 and the cross beam 4 of the restricted area 7, and then connect the traction rope 51 to the right position of the bottom of the cross beam 4 of the open area 8. Four sets of second jacks 6 are installed on the top of the vertical support 3. The four sets of second jacks 6 are vertically arranged upward and distributed at the four corners of the vertical support 3. The four second jacks 6 and the first jack 22 of a pier column 2 adjacent to the vertical support 3 in the open area 8 constitute the support system of the cross beam 4. The pulley 23 is installed on the top of the second jack 6. The pulley 23 on the top of the first jack 22 and the pulley 23 on the top of the second jack 6 are consistent in height, and are both higher than the upper surface of the pier column 2. The second jack 6 and the first jack 22 of the open area 8 constitute the support system of the cross beam 4 of the open area 8. It is convenient for the cross beam 4 of the open area 8 to be in place.

[0048] When the beam 4 is hoisted in the open area 8, there is no need to disassemble the winch 5. The connection point of the traction rope 51 of the winch 5 is transferred from the bottom of the beam 4 in the restricted area 7 to the bottom of the beam 4 in the open area 8. Then the crane hoists the beam 4 to the top of the pier column 2 in the open area 8. The bottom of the beam 4 abuts against the pulley 23 of the first jack 22 and the pulley 23 of the second jack 6. At this time, the beam 4 is placed on the first jack 22 and the second jack 6. Then the winch 5 is started, and the winch 5 reels the traction rope 51. The traction rope 51 pulls the beam 4 to fine-tune the distance between the two beams 4 until they fit together. By fine-tuning the position of the beam 4, the two beams 4 can fit more closely. At this time, the beam 4 is placed on a pier column 2 under the existing elevated 1 and a pier column 2 outside the existing elevated 1. Then the beam 4 in the restricted area 7 and the beam 4 in the open area 8 are closed.

[0049] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A construction method for closing a large-span cap beam with few supports under an existing bridge, characterized in that: The following steps are involved: S1: Divide the installation area of ​​the crossbeam (4) into a restricted area (7) and an open area (8), wherein the area where the crossbeam (4) cannot be directly hoisted into place is the restricted area (7), and the area where the crossbeam (4) can be directly hoisted into place is the open area (8), install an outer cover plate (26) on the top of the bridge pier column (2), the outer cover plate (26) forms a casting template with a closed side, pour concrete on the inner side of the outer cover plate (26) to form a cast-in-place section (25) on the top of the bridge pier column (2), then install a supporting structure and a first jack (22) on the outer side of the outer cover plate (26), build a set of vertical brackets (3) at the open area (8), and install a traction component on the top of the vertical bracket (3); S2: hoisting the cross beam (4) to the top of one of the bridge pier columns (2) in the restricted area (7), the first jack (22) on the top of the bridge pier column (2) supports the bottom of the cross beam (4), the traction assembly pulls the cross beam (4) until the cross beam (4) is moved to the top of the two bridge pier columns (2) in the restricted area (7), the first jack (22) is retracted downward, so that the cross beam (4) is placed on the cast-in-place section (25) on the top of the two bridge pier columns (2); S3: hoisting the cross beam (4) to the top of the bridge pier column (2) in the open area (8), and then closing the cross beam (4) in the restricted area (7) and the cross beam (4) in the open area (8); In the S1, a plurality of steel rods (27) horizontally penetrate two mutually opposite side walls of the outer covering plate (26), and the supporting structure is a steel bracket (21), and the steel bracket (21) is locked to one end of the steel rod (27) extending outward from the outer side of the outer covering plate (26); The traction component is a winch (5), and the traction rope (51) of the winch (5) is connected to the middle position of the bottom of the crossbeam (4); A guide wheel (24) is installed on a steel bracket (21) of a bridge pier column (2) adjacent to the vertical support (3), and the traction rope (51) of the hoist (5) abuts against the surface of the guide wheel (24).

2. According to claim 1, a method for closing a large-span cap beam with few supports under an existing bridge is characterized in that: A pulley (23) is installed on the top of the first jack (22).

3. The method for closing a large-span cap beam with few supports under an existing bridge according to claim 1 is characterized in that: In the above S3, a second jack (6) is installed on the top of the vertical support (3), and the second jack (6) and the first jack (22) of the open area (8) form a support system for the crossbeam (4).

4. The method for closing a large-span cap beam with few supports under an existing bridge according to claim 1 is characterized in that: The position of the hoist (5) is lower than the upper surface of the pier column (2).

5. The method for closing a large-span cap beam with few supports under an existing bridge according to claim 3 is characterized in that: In S3, the traction rope (51) of the winch (5) is connected to the bottom of the beam (4) at the open area (8). After the beam (4) is placed on the first jack (22) and the second jack (6), the winch (5) is used to pull the beam (4) to fine-tune the distance between the two beams (4) until they are joined together, and finally the closing construction is carried out.

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