CN110644349A - Superstructure for wide box girder and short tower cable-stayed bridge and construction method - Google Patents

Abstract

The invention relates to an upper structure and a construction method for a wide box girder low tower cable-stayed bridge, comprising a main girder body, the main girder body is a box girder structure, and two sides of the upper surface of the main girder body are symmetrical respectively A bridge deck assembly is overlapped; a diagonal bracing assembly is arranged between the main beam body and the bridge deck assembly, the diagonal bracing assembly is arranged obliquely, and the lower end of the diagonal bracing assembly is fixed with the lower part of the main girder body, The upper end of the diagonal brace assembly is in contact with the lower end surface of the inclined surface assembly and realizes the support of the bridge deck assembly; the bridge deck assembly can realize the extension of the main girder body in the width direction, and the main girder body and the bridge deck assembly form Bridge deck beam structure. The invention can reduce the shear lag effect of the main girder body of the wide box girder low tower cable-stayed bridge, improve the lateral force performance of the main girder body, and solve the problem that the conventional hanging basket cannot meet the cantilever casting of the wide box girder of the low tower cable-stayed bridge. question.

Description

A kind of superstructure and construction method for wide box girder low tower cable-stayed bridge

technical field

The invention belongs to the technical field of bridges, and in particular relates to an upper structure and a construction method for a wide box girder low tower cable-stayed bridge.

Background technique

Cable-stayed bridge with short tower, also known as partial cable-stayed bridge, is a kind of beam and cable combined system bridge between continuous beam and cable-stayed bridge. The cable-stayed bridge with low tower has good economic performance because of its low tower and low beam, which reduces the fatigue of the cable, improves the utilization rate of the cable, and has good economic performance. The height of the beam body is about 1/2 of the continuous beam of the same span, and the appearance is light; therefore, it has a wide range of application prospects.

Due to the section stress characteristics of the main girder body, the cable towers of the cable-stayed bridges with short towers are mostly arranged in the central dividing belt, and the central cable plane is adopted. In recent years, with the continuous increase of domestic traffic, the construction of six-lane and eight-lane width projects on high-grade highways in my country, especially long-span bridges spanning large rivers and rivers, has begun to construct six-lane and eight-lane width projects. The lateral force of the main girder body is more complex, and the shear lag effect is more obvious, which reduces the mechanical performance of the main girder body, and affects the application and promotion of the low tower cable-stayed bridge in the wide box girder.

The inventor learned that: in the construction of cable-stayed bridges with low towers, the hanging basket cantilever casting method is generally used for construction. Compared with the construction of full-floor brackets, this method can better overcome the unfavorable terrain, so that the upper structure of the bridge can be constructed in sections, which has the advantages of construction. It has the advantages of simplicity, less cost, good structural integrity, relatively simple maintenance and less maintenance workload.

However, the inventor believes that: for the two-way six-lane and two-way eight-lane central cable-plane low-tower cable-stayed bridges, due to the wider box girder and the increased lateral width of the hanging basket, the conventional hanging basket cannot meet the force requirements, and the design must be re-enhanced. , which not only increases the cost, but also brings new challenges to the design, manufacture and safety of the wide hanging basket in the cantilever construction process.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a superstructure and construction method for a wide box girder low tower cable-stayed bridge, which can reduce the shear lag effect of the main girder body of the wide box girder low tower cable-stayed bridge, improve the main girder The lateral force performance of the body and the problem that the conventional hanging basket can not meet the cantilever casting of the wide box girder of the low tower cable-stayed bridge.

In order to achieve the above purpose, the present invention adopts the following technical scheme: a superstructure for a wide box girder low tower cable-stayed bridge, comprising a main girder body, the main girder body is a box girder structure, and the main girder body is Bridge deck components are symmetrically overlapped on both sides of the upper surface;

A diagonal bracing assembly is arranged between the main beam body and the bridge deck assembly, the diagonal bracing assembly is arranged obliquely, the lower end of the diagonal bracing assembly is fixed with the lower part of the main beam body, and the diagonal bracing assembly is The upper end is in contact with the lower end surface of the inclined plane assembly and realizes the support of the bridge deck assembly;

The bridge deck assembly is a longitudinal force bearing member on the support and diagonal brace assembly, which can realize the extension of the main girder body in the width direction, and the main girder body and the bridge deck assembly form a bridge deck girder body structure.

Further, the diagonal brace assembly includes a steel pipe, the lower end of the steel pipe is fixedly installed with a base, the lower parts of the two sides of the main beam body are respectively provided with embedded steel plates, and the base and the embedded steel plates are fixedly connected by embedded bolts. .

Further, the diagonal brace assembly includes U-shaped channel steel, the U-shaped channel steel is arranged horizontally, the U-shaped channel steel is located directly below the bridge deck assembly, the U-shaped channel steel is fixedly connected with the steel pipe, and the U-shaped channel steel is fixedly connected. Concrete is poured into the channel steel, and the upper surface of the U-shaped channel steel is in contact with the lower surface of the deck assembly for support.

Further, legs are provided on both sides of the main beam body, and the legs are used to overlap the bridge deck assembly, and the bridge deck assembly and the upper surface of the main beam body are connected by wet joints. The joint is a cast-in-place concrete structure.

Further, the bridge deck assembly includes a prefabricated panel, and the prefabricated panel is a square panel.

Further, one end of the U-shaped channel steel close to the main beam body is fixedly provided with an end plate, and one side of the main beam body close to the U-shaped channel steel is provided with pre-embedded bolts, and the pre-embedded bolts are fixedly connected to the end plate.

Further, the bridge deck components on each side of the main beam body are formed by splicing a plurality of prefabricated panels in sequence, and the plurality of prefabricated panels on the same side are connected by wet joints.

The invention also provides a construction method suitable for a wide box girder low tower cable-stayed bridge, and the constructed wide box girder low tower cable-stayed bridge utilizes the wide box girder low tower cable-stayed bridge. The superstructure of the bridge, including the following steps:

Step 1, bottom structure construction: including pile foundation, bearing platform and bridge pier pier construction;

Step 2, use the bracket method to construct the intermediate beam body, the connecting segment and the tower column, and install the hanging basket;

Step 3, the beam section in the cable-free area of the main beam body is constructed by cantilever, and the longitudinal prestress is tensioned; lag one or more beam sections, firmly connect the steel diagonal bracing assembly with the embedded part of the main beam body, and hoist the prefabricated plate , pouring transverse wet joints;

Step 4, the beam section in the cable area of the main beam body adopts cantilever construction, the hanging basket moves from the bridge tower to both sides, the main beam body is constructed symmetrically, and the longitudinal prestressing is tensioned; and the stay cables are installed in sequence, and tensioned in place;

The lateral diagonal bracing joint section lags behind one or more beam sections for synchronous construction; install side span cast-in-place brackets, and pour the side span cast-in-place section;

Step 5: Complete the construction of the mid-span and side-span closed sections of the main girder body, and stretch the longitudinal prestressed steel bundles of the closed section, synchronously construct the steel diagonal brace assemblies, and pour the longitudinal wet joints of the bridge deck;

Further, in the step 3, concrete is poured into the steel pipe; when the concrete in the steel pipe reaches the design strength, the prefabricated plate is hoisted above the steel diagonal brace assembly.

Beneficial effects of the present invention:

1) The wide box girder of the cable-stayed bridge with a low tower is divided into zero pieces. The wide box girder is formed by splicing the narrow main girder body and the bridge deck components, which is convenient for the construction of the girder body by using the hanging basket, and the force of each component is more clear and clear. ;

2) Cantilever pouring can be carried out by using the conventional width hanging basket, which avoids the redesign of the wide hanging basket, reduces the construction difficulty and saves the construction cost; reduces the shear lag effect of the entire width box girder of the traditional low tower cable-stayed bridge Impact.

3) The width of the main beam can be adapted to the range below 42 meters, which can meet the width requirements of most existing highways, municipal roads, and ordinary highway bridges;

Description of drawings

The accompanying drawings that constitute a part of the present application are used to provide further understanding of the present application, and the schematic embodiments and descriptions of the present application are used to explain the present application and do not constitute a limitation to the present application.

1 is a schematic cross-sectional view of a main beam body in an embodiment of the present invention;

Fig. 2 is the detailed structural representation of part A in Fig. 1;

3 is a schematic structural diagram of an end sealing plate in an embodiment of the present invention;

Fig. 4 is the detailed structural representation of part B in Fig. 1;

5 is a schematic diagram of the plane layout of the prefabricated board in the embodiment of the present invention;

6 is a schematic diagram of a transverse joint of a prefabricated panel in an embodiment of the present invention;

Fig. 7 is the division diagram of the cross-sectional area of the wide box girder in the embodiment of the present invention;

Fig. 8 is the front view direction schematic diagram of the lower structure construction in the embodiment of the present invention;

9 is a schematic top view of the construction of the lower structure in the embodiment of the present invention;

Fig. 10 is the schematic diagram of the tower column construction in the main view direction in the embodiment of the present invention;

Figure 11 is a schematic diagram of tower construction in a top view direction in an embodiment of the present invention;

12 is a schematic diagram of cantilever pouring of the beam section in the cable-free area of the main beam body in the front view direction according to the embodiment of the present invention;

13 is a schematic diagram of cantilever pouring of the beam section of the main beam body without cable in the top view direction according to the embodiment of the present invention;

14 is a schematic diagram of cantilever casting and installation of stay cables in the cable section of the main beam body in the front view direction according to the embodiment of the present invention;

15 is a schematic diagram of cantilever casting and installation of stay cables in the cable section of the main beam body in the top view direction according to the embodiment of the present invention;

16 is the construction of the main beam body closing section in the main view direction in the embodiment of the present invention;

17 is the construction of the closing section of the main beam body in the top view direction in the embodiment of the present invention;

Fig. 18 is the construction of the auxiliary structure in the front view direction in the embodiment of the present invention;

Fig. 19 is the construction of the auxiliary structure in the top view direction in the embodiment of the present invention;

In the picture: 1. Main beam body; 2. Diagonal brace assembly; 3. Bridge deck assembly; 4. End plate; 5. Wet joint; 6. Prefabricated plate; 7. U-shaped channel steel; 8. Embedded bolt ;9, embedded flange steel plate; 10, flange steel plate base; 11, square steel pipe; 12, rivet; 13, bridge pier; 13A, cap; 13B, pile foundation; 14, cast-in-place support; 15, hanging basket; 16, tower column; 17, connecting segment; 18, segment without stay cable; 19, guardrail; 20, side span cast-in-place segment; 20A, side span cast-in-place bracket; 21, stay cable.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

In a typical embodiment of the present invention, as shown in 1-3, a superstructure for a wide box girder low tower cable-stayed bridge includes a main girder body 1, and the main girder body 1 is a box girder structure , the two sides of the upper surface of the main beam body 1 are respectively overlapped with bridge deck components 3 symmetrically;

A diagonal bracing assembly 2 is arranged between the main beam body 1 and the bridge deck assembly 3, the diagonal bracing assembly 2 is arranged obliquely, and the lower end of the diagonal bracing assembly 2 is fixed with the lower part of the main beam body 1, so The upper end of the diagonal brace assembly 2 is in contact with the lower end surface of the inclined plane assembly and realizes the support of the bridge deck assembly;

The bridge deck assembly 3 can realize the extension of the main girder body 1 in the width direction, and the main girder body 1 and the bridge deck assembly 3 form a bridge deck girder body structure.

Specifically, the main beam body 1 is a concrete main beam body 1, the concrete main beam body 1 and the bridge deck assembly 3 (prefabricated plate 6) can be made of concrete above C50, and the material of the steel diagonal brace assembly 2 can be Q355 in the national standard , Q370, Q420 grade steel. The steel main beam body 1 and the concrete bridge deck are connected by cylindrical head welding studs. The shear studs are generally M19 and M22, and the length is 2/3 of the height of the U-shaped channel steel 7, and not less than 15 cm.

During the construction of the wide box girder structure, the middle main box girder is first cantilevered with hanging basket 15, then the steel diagonal brace assembly 2 is installed, and it is firmly connected with the embedded steel bars or embedded bolts 8 of the middle main box girder, and then the prefabricated plate is hoisted. 6. Finally, the wet joint 5 is poured to form a whole and bear the force together.

The diagonal brace assembly 2 includes a steel pipe, the lower end of the steel pipe is fixedly installed with a base, the lower parts of the two sides of the main beam body 1 are respectively provided with embedded steel plates, and the base and the embedded steel plates are fixed by embedded bolts 8 . connect.

Specifically, the steel pipe can be a square steel pipe 11 . The base is a flanged steel plate base 10 , and the pre-embedded steel plate is a pre-embedded flanged steel plate 9 .

In some embodiments, the top width B1 of the main beam body 1 may be 34-42 meters; the bottom width B2=0.5-0.6B1; the cantilever length of the middle box girder B3=0.8-1.0 meters; 0.15B1, B5=0.08～0.1B1, the standard spacing of steel diagonal braces is d=4.0 or 4.5m; the height H1 of the main girder body 1 is determined according to the actual bridge span; the thickness of the bridge deck is H2=0.25～0.3m.

The diagonal brace assembly 2 includes a U-shaped channel steel 7, the U-shaped channel steel 7 is arranged horizontally, the U-shaped channel steel 7 is located directly below the bridge deck assembly 3, and the U-shaped channel steel 7 is fixedly connected with the steel pipe, Concrete is poured into the U-shaped channel steel 7, and the upper surface of the U-shaped channel steel 7 is in contact with the lower surface of the bridge deck assembly 3 for support.

Specifically, rivets should be provided in the U-shaped channel steel to facilitate concrete fixation.

The two sides of the main beam body 1 are provided with legs, and the legs are used to overlap the bridge deck assembly 3, and the bridge deck assembly 3 and the upper surface of the main beam body 1 are connected by wet joints 5, so The wet joint 5 is a cast-in-place concrete structure.

The bridge deck assembly 3 includes a prefabricated panel 6, and the prefabricated panel 6 is a square panel.

One end of the U-shaped channel steel 7 close to the main beam body 1 is fixedly provided with an end plate 4, and one side of the main beam body 1 close to the U-shaped channel steel 7 is provided with embedded bolts 8. The embedded bolts 8 and The end plate 4 is fixedly connected.

The bridge deck assembly 3 on each side of the main beam body 1 is formed by splicing a plurality of prefabricated panels 6 in sequence, and the plurality of prefabricated panels 6 on the same side are connected by wet joints 5 .

Specifically, a cable-stayed bridge with a short tower has the characteristics of rigid beam, low tower and concentrated stay cables. The wide box girder section proposed in this embodiment is suitable for low tower cable-stayed bridges. The entire section is divided into a relatively narrow box girder in the middle and a combination of transverse steel diagonal braces. The middle main box girder provides the overall stiffness of the bridge and meets the requirements of The space required for longitudinal prestressing layout and bear the longitudinal force of the main beam; the cross-bracing joint section provides sufficient section width and bears the lateral local force; the ratio of the lateral length to the longitudinal length of the prefabricated panel 6 is close to 2, which is short For a one-way slab that bears loads on its sides, only distributed reinforcement bars need to be configured along the long side.

This embodiment also provides a construction method suitable for a wide box girder low tower cable-stayed bridge. The superstructure of the pull bridge, including the following steps:

Step 1, the construction of the bottom structure: including the construction of the pier body of the pile foundation 13B, the bearing platform 13A and the bridge pier 13;

Step 2, using the bracket method to carry out the construction of the main beam body 1, the connecting segment 17 and the segment and the tower column 16, and install the hanging basket 15;

Step 3, the cable-free segment 18 of the main beam body 1 is constructed by cantilever, and the longitudinal prestressing is tensioned; one or more beam segments are delayed, and the steel diagonal brace assembly 2 is firmly connected to the embedded part of the main beam body 1. , hoisting prefabricated panels 6, pouring transverse wet joints 5;

In step 4, the section with cables of the main beam body 1 is constructed by cantilever, the hanging basket 15 is moved from the bridge tower to both sides, the main beam body 1 is constructed symmetrically, and the longitudinal prestressing is tensioned; and the stay cables 21 are installed in sequence, tension in place;

The lateral diagonal bracing joint section lags behind one or more beam sections and is constructed synchronously; install the side span cast-in-place bracket 20A, and pour the side span cast-in-place section 20;

Step 5: Complete the construction of the mid-span and side-span closed sections of the main girder body 1, and stretch the longitudinal prestressed steel bundles of the closed section, synchronously construct the steel diagonal brace assembly 2, and pour the longitudinal wet joint 5 of the bridge deck;

After the bridge deck is cured, the bridge deck pavement, guardrail 19, expansion joints, lamp posts and other auxiliary structures will be constructed.

In the step 3, concrete is poured into the steel pipe; when the concrete in the steel pipe reaches the design strength, the prefabricated plate 6 is hoisted above the steel diagonal brace assembly 2 .

Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, they do not limit the scope of protection of the present invention. Those skilled in the art should understand that on the basis of the technical solutions of the present invention, those skilled in the art do not need to pay creative work. Various modifications or deformations that can be made are still within the protection scope of the present invention.

Claims (9)

1. The upper structure for the wide box girder and short tower cable-stayed bridge is characterized by comprising a main girder body, wherein the main girder body is of a box girder structure, and bridge deck components are symmetrically lapped on two sides of the upper surface of the main girder body respectively;

an inclined strut assembly is arranged between the main beam body and the bridge deck assembly, the inclined strut assembly is obliquely arranged, the lower end of the inclined strut assembly is fixed with the lower part of the main beam body, and the upper end of the inclined strut assembly is in contact with the lower end face of the inclined plane assembly to support the bridge deck assembly;

the bridge deck assembly can realize the extension of the main beam body in the width direction, and the main beam body and the bridge deck assembly form a bridge deck beam body structure.

2. The superstructure for a wide box girder short tower cable-stayed bridge according to claim 1, wherein the diagonal brace assembly comprises a steel pipe, a base is fixedly installed at the lower end of the steel pipe, embedded steel plates are respectively arranged at the lower parts of the two side surfaces of the main girder body, and the base is fixedly connected with the embedded steel plates through embedded bolts.

3. The superstructure for wide box girder short tower cable-stayed bridges according to claim 1, wherein the bracing assembly comprises a U-shaped channel steel, the U-shaped channel steel is horizontally arranged, the U-shaped channel steel is positioned right below the bridge deck component and is fixedly connected with the steel pipe, concrete is poured in the U-shaped channel steel, and the upper surface of the U-shaped channel steel is in contact with the lower surface of the bridge deck component to realize support.

4. The superstructure for a wide box girder short tower cable-stayed bridge according to claim 1, wherein the main girder body is provided at both sides thereof with legs for overlapping the deck assembly, the deck assembly is connected with the upper surface of the main girder body by a wet joint, and the wet joint is a concrete cast-in-place structure.

5. The superstructure for wide box girder short tower cable-stayed bridges according to claim 1, wherein the deck assembly comprises precast slabs, which are square slab members.

6. The superstructure for a wide box girder short tower cable-stayed bridge according to claim 3, characterized in that an end plate is fixedly arranged at one end of the U-shaped channel steel close to the girder body, and a pre-buried bolt is arranged at one side of the girder body close to the U-shaped channel steel and fixedly connected with the end plate.

7. The superstructure for a wide box girder short tower cable-stayed bridge according to claim 1, wherein the deck assembly at each side of the main girder is formed by sequentially splicing a plurality of precast slabs, and the precast slabs at the same side are connected by wet joints.

8. A construction method suitable for a wide box girder and short tower cable-stayed bridge, which is characterized in that the constructed wide box girder and short tower cable-stayed bridge utilizes the superstructure for the wide box girder and short tower cable-stayed bridge as claimed in any one of claims 1 to 7, and comprises the following steps:

step 1, bottom structure construction: the construction method comprises the following steps of constructing a pile foundation, a cushion cap and a pier body;

step 2, constructing the middle beam body, the connecting sections and the tower column by adopting a support method, and installing a hanging basket;

step 3, adopting cantilever construction for the ropeless area beam section of the main beam body, and tensioning longitudinal prestress; lagging one or more beam sections, firmly connecting the steel inclined strut assembly with the embedded part of the main beam body, hoisting the precast slab, and pouring a transverse wet joint;

step 4, constructing the girder section with the cable of the main girder body by using a cantilever, moving the hanging basket from the bridge tower to two sides, symmetrically constructing the main girder body, and tensioning longitudinal prestress; sequentially installing stay cables and tensioning in place;

the transverse inclined strut combination section lags behind one or more beam sections to carry out construction synchronously; installing a side span cast-in-place support, and pouring a side span cast-in-place section;

and 5, completing construction of the closure section of the middle span and the side span of the main girder body, tensioning longitudinal prestressed steel bundles of the closure section, synchronously constructing a steel diagonal bracing assembly, and pouring a longitudinal wet joint of the bridge deck.

9. The construction method for the wide box girder short tower cable-stayed bridge according to claim 8, wherein in the step 3, concrete is poured into the steel pipe; and when the concrete in the steel pipe reaches the designed strength, hoisting the precast slab above the steel inclined strut assembly.

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