CN116289559A

CN116289559A - Low-low lower tower column bridge tower and construction method

Info

Publication number: CN116289559A
Application number: CN202310374649.9A
Authority: CN
Inventors: 张金涛; 喻济昇; 潘韬; 张景钰; 段雪炜; 梅新咏; 邱远喜; 王军炜; 卓锦沂; 贾世伟
Original assignee: China Railway Major Bridge Reconnaissance and Design Institute Co Ltd
Current assignee: China Railway Major Bridge Reconnaissance and Design Institute Co Ltd
Priority date: 2023-04-10
Filing date: 2023-04-10
Publication date: 2023-06-23

Abstract

The invention discloses a low-low tower column bridge tower and a construction method, which relate to the technical field of bridge engineering, wherein the low-low tower column bridge tower comprises: bearing platform; the two-limb tower columns are symmetrically arranged on the bearing platform, each of the two-limb tower columns comprises an upper tower column and a lower tower column, the two-limb lower tower columns incline outwards along the transverse bridge by a set angle, the tops of the two-limb lower tower columns are respectively connected with the bottoms of the two-limb upper tower columns, and the tops of the two-limb upper tower columns are connected together; the two ends of the lower cross beam are respectively arranged at the joint of the two upper tower columns and the lower tower column and are used for supporting the main beam; pier stud, it sets up on the cushion cap to support the bottom end rail. The rigidity of the lower cross beam is increased, so that the load born by the lower cross beam is transferred to the pier column, the load born by the tower column is dispersed, and the stress of the tower column is improved. The problem of exist topography and bridge floor elevation restriction in the prior art, the lower beam is less apart from the tower bottom, and lower beam and lower tower column produce the frame effect, have reduced the application efficiency of crossbeam prestressing force, the increase design degree of difficulty is solved.

Description

Low-low lower tower column bridge tower and construction method

Technical Field

The invention relates to the technical field of bridge engineering, in particular to a bridge tower with a low-level lower tower column and a construction method.

Background

The bridge tower is used as a main stress member of a large-span cable-stayed bridge and a suspension bridge and bears the bending action, and comprises an upper tower column, a middle tower column, a lower tower column, an upper cross beam, a lower cross beam and other structures. The crossbeam is as the important component part of main tower, and its effect has three: firstly, the cross beam increases the overall stability of the bridge tower; secondly, the lower cross beam provides an installation space for force transmission devices such as a first support, a damper and the like; and thirdly, the lower cross beam transmits part of bridge deck load to the tower column through the first support, the damper and the like.

The lower beam mostly adopts a prestressed concrete structure, under the action of limiting working conditions, the shearing force, bending moment and torque born by the bridge tower beam are larger, and the bending bearing capacity, shearing bearing capacity, torsion bearing capacity and crack resistance checking calculation are difficult to meet the requirements during design.

In the prior art, the design requirements are generally met by increasing the height and reinforcement ratio of the cross beam. When the distance between the lower cross beam and the tower bottom is smaller, the lower cross beam and the lower tower column generate a frame effect, so that the application efficiency of cross beam prestress is reduced, and the design difficulty is increased.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a low-down tower column bridge tower and a construction method, which can solve the problems in the prior art.

In order to achieve the above purpose, the invention adopts the following technical scheme:

in one aspect, the present solution provides a low-profile pylon comprising:

bearing platform;

the two-limb tower columns are symmetrically arranged on the bearing platform, each tower column comprises an upper tower column and a lower tower column, the two-limb lower tower columns incline outwards along the transverse bridge by a set angle, the tops of the two-limb lower tower columns are respectively connected with the bottoms of the two-limb upper tower columns, and the tops of the two-limb upper tower columns are connected together;

the two ends of the lower cross beam are respectively arranged at the joint of the upper tower column and the lower tower column of the two limbs and are used for supporting the main beam;

and the pier column is arranged on the bearing platform and supports the lower cross beam.

In some alternatives, the pier stud has a horizontal cross-sectional area that gradually decreases from top to bottom.

In some alternatives, a first support is provided between the lower beam and the pier.

In some alternatives, the first mount comprises:

the bottom plate is provided with a groove at the top and is arranged at the top of the pier stud;

the bottom of the top plate is provided with a lug which can slide along the transverse bridge in the groove, and the top plate is arranged at the bottom of the lower cross beam.

In some alternatives, the bottom of the bump and the bottom of the groove are both provided with mirror-surface steel plates.

In some alternatives, the bottom plate and top plate are bolted to the pier stud and lower cross beam, respectively.

In some alternatives, a damper is provided on top of the lower cross beam for limiting movement of the main beam along the longitudinal bridge.

In some alternatives, a second support is provided between the lower column and the lower cross member.

In some alternative schemes, the tower column, the lower cross beam and the pier column are all hollow box structures.

On the other hand, the scheme also provides a construction method of the low-altitude lower tower column bridge tower, which is used for constructing the low-altitude lower tower column bridge tower and comprises the following steps:

pouring a bearing platform, and pouring the bottoms of the lower tower columns and the pier columns by turning over a mould;

the climbing form is used for pouring the lower tower column and the rest part of the pier column;

a bracket is arranged between the lower tower column and the pier column, a lower cross beam is poured, and the lower cross beam is tensioned to be prestressed;

and (5) removing the bracket, and pouring the upper tower column by the climbing form.

Compared with the prior art, the invention has the advantages that: the pier column that this scheme was through setting up on the cushion cap provides support for the lower beam of the last column and lower column junction of connecting at both limbs column. The rigidity of the lower cross beam is increased, the load born by the lower cross beam is partially transmitted to the pier column, the load born by the tower column is dispersed, the stress of the tower column is improved, the problems that in the prior art, local terrain and bridge deck elevation limit exist, when the distance between the lower cross beam and the tower bottom is smaller, the lower cross beam and the lower tower column generate a frame effect, the application efficiency of the prestressing force of the lower cross beam is reduced, and the design difficulty is increased are solved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a low-profile pylon according to an embodiment of the present invention;

FIG. 2 is a schematic illustration of a multi-support elevation arrangement of a lower cross member of a bridge tower in accordance with an embodiment of the present invention;

FIG. 3 is a schematic view of a longitudinal bridge view of a first support according to an embodiment of the present invention;

FIG. 4 is a schematic view of a longitudinal bridge view of a second support according to an embodiment of the present invention;

FIG. 5 is a schematic view of a pier stud according to an embodiment of the present invention;

FIG. 6 is a schematic horizontal cross-section of a pier stud in accordance with an embodiment of the present invention;

FIG. 7 is a schematic top view of the arrangement of the first and second supports on the lower cross member in an embodiment of the invention;

FIG. 8 is a schematic mechanical diagram of the lower beam after bridging in an embodiment of the present invention;

FIG. 9 is a mechanical schematic diagram of a tensioning pre-stress stage in the lower beam construction process in an embodiment of the invention;

FIG. 10 is a schematic flow chart of a method of constructing a low-profile lower column bridge tower in an embodiment of the invention;

in the figure: 1. bearing platform; 2. a tower column; 21. a tower column is arranged; 22. a lower tower column; 3. a lower cross beam; 4. a main beam; 5. pier column; 6. a first support; 61. a bottom plate; 62. a top plate; 7. a damper; 8. and a second support.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.

Embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

As shown in fig. 1, the present invention provides a low-profile tower bridge tower, comprising:

a bearing platform 1;

the two-limb tower columns 2 are symmetrically arranged on the bearing platform 1, each of the two-limb tower columns 2 comprises an upper tower column 21 and a lower tower column 22, the two-limb lower tower columns 22 incline outwards along the transverse bridge by a set angle, the tops of the two-limb lower tower columns 22 are respectively connected with the bottoms of the two-limb upper tower columns 21, and the tops of the two-limb upper tower columns 21 are connected together;

the two ends of the lower cross beam 3 are respectively arranged at the joint of the two upper tower columns 21 and the lower tower column 22 and used for supporting the main beam 4;

pier 5, it sets up on cushion cap 1, and supports the bottom end rail 3.

In this embodiment, the support is provided for the lower cross member 3 connected to the junction of the upper column 21 and the lower column 22 of the two-leg column 2 by the pier 5 provided on the deck 1. The rigidity of the lower cross beam 3 is increased, so that the load born by the lower cross beam 3 is partially transferred to the pier column 5, the load born by the tower column 2 is dispersed, the stress of the tower column 2 is improved, and the problems that in the prior art, local terrain and bridge deck elevation limit exist, when the distance between the lower cross beam 3 and the tower bottom is smaller, the lower cross beam 3 and the lower tower column 22 generate a frame effect, the application efficiency of the prestress of the lower cross beam 3 is reduced, and the design difficulty is increased are solved.

In some alternative embodiments, as shown in fig. 2, 5 and 6, the horizontal cross-sectional area of the pier stud 5 gradually decreases from top to bottom.

In this embodiment, the pier stud 5 has a large top cross section for providing a sufficient support surface for the lower beam 3. The structural form with large upper part and small lower part saves the concrete consumption and reduces the cost on the premise of meeting the stress.

In some alternative embodiments, a first abutment 6 is provided between the lower cross member 3 and the abutment 5.

In this embodiment, the first support 6 is provided to better support the lower beam 3.

As shown in fig. 3, in some alternative embodiments, the first support 6 comprises:

a bottom plate 61, the top of which is provided with a groove, the bottom plate 61 being arranged on the top of the pier 5;

the top plate 62 has a projection provided at the bottom thereof, which can slide in the groove in the lateral direction along the bridge, and the top plate 62 is provided at the bottom of the lower cross member 3.

In this embodiment, the structure of the first support 6 can prevent the lower cross member 3 from being displaced in the longitudinal bridge direction during the tensioning prestressing at the construction stage. In the bridge operation stage, the longitudinal force of the main girder under the action of wind load or earthquake load is transferred.

In some alternative embodiments, the bottom of the bump and the bottom of the groove are each provided with a mirror plate.

In the embodiment, the mirror surface steel plate is a stainless steel plate and is welded with the bottom of the convex block and the bottom of the groove. The coefficient of slip resistance between the two mirror-surface steel plates is not more than 0.1. So that the top plate 62 and the bottom plate 61 can slide in the lateral direction.

In some alternative embodiments, the bottom plate 61 and top plate 62 are bolted to the pier stud 5 and lower beam 3, respectively.

In this embodiment, the stability of the connection between the bottom plate 61 and the top plate 62 and the pier stud 5 and the lower cross member 3 is ensured by bolting.

In some alternative embodiments, the top of the lower cross beam 3 is provided with a damper 7 for limiting the movement of the main beam 4 in the longitudinal bridge direction.

In some alternative embodiments, a second support 8 is provided between the lower tower 22 and the lower cross member 3.

As shown in fig. 4, in the present embodiment, the second support 8 includes a first support top plate connected to the lower tower 22 and a first support bottom plate connected to the lower cross member 3, and the first support top plate and the first support bottom plate are slidable in the lateral bridge direction and the longitudinal bridge direction through mirror surface steel plates therebetween. Limiting stops are arranged on two sides of the longitudinal bridge direction of the bottom plate of the first support, and excessive longitudinal bridge displacement is prevented when the prestressing force is tensioned.

Fig. 7 shows a schematic plan view of the arrangement of the first and second supports on the lower cross member 3.

The lower beam 3 after bridge formation is taken as a separator for analysis, the action of the tower column 2 on the lower beam 3 can be simplified into a fixed first support, the action of the pier column 5 on the lower beam 3 can be simplified into a movable hinge first support, and the action of the main beam 4 on the lower beam 3 can be simplified into a load F, as shown in fig. 8. The span of the lower cross beam 3 is greatly reduced, and the bending, shearing and torsion rigidity of the lower cross beam 3 is increased. The load transferred by the main beam 4 to the lower beam 3 is also mostly directly born by the pier 5, and the load born by the lower beam 3 is reduced

In some alternative embodiments, the tower column 2, the lower cross beam 3 and the pier column 5 are all hollow box structures.

In the embodiment, the hollow box structure has good stress performance, reduces the dead weight of the tower column and saves the consumption of concrete.

As shown in fig. 10, in another aspect, the present invention further provides a method for constructing a low-profile tower, for constructing the low-profile tower, comprising the steps of:

s1: and pouring the bearing platform 1, and pouring the bottoms of the lower tower columns 22 and the pier columns 5 by turning over the mould.

S2: the creeping formwork is used for pouring the lower tower column 22 and the rest of the pier column 5.

S3: and a bracket is arranged between the lower tower column 22 and the pier column 5, the lower cross beam 3 is poured, and the lower cross beam 3 is tensioned for prestress.

In this embodiment, the second support 8 is disposed at the top of the segment of the lower tower column 22, so as to isolate the lower tower column 22 from the lower beam 3, so that the prestress is borne by the lower beam 3, and the influence of the prestress on the lower tower column 22 is reduced, and the mechanical schematic diagram is shown in fig. 9.

S4: and (5) removing the bracket, and pouring the upper tower column 21 by using the climbing form.

In this embodiment, after the prestressing force is applied to the lower beam 3, the lower beam 3 and the lower tower column 22 are connected into a whole, and then the upper tower column 21 is poured, so that the shrinkage creep effect of the concrete is reduced, and the cracking risk of the concrete is reduced.

Taking a main span 688m sea-crossing bridge as an example, the total height of the tower column is 232.5m, the height of the lower tower column is 42.5m, and the span of the lower cross beam is 31m. The bridge adopts a longitudinal constraint system, the tower beams are separated, a vertical first support is arranged between the tower beams, and a longitudinal constraint is arranged at one tower. Bridge site base wind speed 46.5m/s; and (5) carrying out earthquake-proof design according to two-stage level fortification.

The stress conditions of the lower beam of the pier column supporting lower beam and the lower beam of the pier column supporting lower beam which are not adopted under the action of strong wind and the action of earthquake are respectively compared, as shown in table 1:

TABLE 1

The structure that the pier supports the lower cross beam is adopted, the maximum positive bending moment of the cross beam is changed to be 0.93 times of the original positive bending moment under the action of strong wind, and the maximum negative bending moment is changed to be 0.93 times of the original negative bending moment; under the action of earthquake, the maximum bending moment of the cross beam is changed to be 0.86 times of the original bending moment, and the minimum bending moment is changed to be 0.89 times of the original bending moment; the bending moment of the lower cross beam supported by the pier is reduced.

The stress conditions of the bottom of the lower tower column are respectively compared with those of the lower beam supported by the pier column and those of the lower beam not supported by the pier column under the action of strong wind and the earthquake, as shown in table 2:

TABLE 2

The structure that the pier column supports the lower cross beam is adopted, the maximum positive bending moment of the tower bottom is changed to be 0.85 times of the original maximum negative bending moment under the action of strong wind, and the maximum negative bending moment is changed to be 0.85 times of the original maximum negative bending moment; under the action of earthquake, the maximum bending moment of the tower bottom is changed to be 0.77 times of the original bending moment, and the minimum bending moment is changed to be 0.78 times of the original bending moment; after the pier is adopted to support the lower cross beam, the bending moment at the bottom of the tower is reduced.

Compared with the traditional construction method, the novel construction method has the effects on the lower cross beam and the lower tower column as shown in Table 3:

TABLE 3 Table 3

By adopting the construction method, the application efficiency of the prestress is improved by 6%, the maximum positive bending moment of the lower tower column is reduced to 0, the maximum negative bending moment is reduced to 0.65 times of that of the traditional method, and the bending moment of the lower tower column is greatly reduced.

By adopting the measure of setting temporary support before stretching the prestressing of the lower beam, the application efficiency of the prestressing of the lower beam can be improved, the number of prestressing steel bundles is reduced, meanwhile, the bending moment generated by shrinkage and creep of the concrete of the tower column is also effectively reduced, and the risk of concrete cracking is reduced.

In summary, the pier columns are arranged below the lower beam to provide support, so that the span of the lower beam is reduced, the rigidity of the lower beam is increased, and the lower beam can bear larger shearing force, bending moment and torque; the cross-sectional dimension of the lower beam is smaller than an unsupported lower beam. The load part born by the lower cross beam is directly transferred to the pier column through the support, so that the load born by the tower columns at two sides is dispersed, and the stress of the tower columns is improved. After the prestress is applied to the lower cross beam, the lower cross beam and the lower tower column are connected into a whole, so that the shrinkage and creep effects of concrete are reduced, and the cracking risk of the concrete is reduced. The cast-in-situ bracket of the lower beam is avoided, only a few temporary brackets are required to be arranged between the pier column and the tower column, and the construction is convenient. The overall stability of the bridge tower is improved.

In the description of the present application, it should be noted that the azimuth or positional relationship indicated by the terms "upper", "lower", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of description of the present application and simplification of the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application. Unless specifically stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

It should be noted that in this application, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely a specific embodiment of the application to enable one skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-profile lower column bridge tower, comprising:

a bearing platform (1);

the two-limb tower columns (2) are symmetrically arranged on the bearing platform (1), each tower column (2) comprises an upper tower column (21) and a lower tower column (22), the two-limb lower tower columns (22) incline outwards along a transverse bridge for a set angle, the tops of the two-limb lower tower columns are respectively connected with the bottoms of the two-limb upper tower columns (21), and the tops of the two-limb upper tower columns (21) are connected together;

the two ends of the lower cross beam (3) are respectively arranged at the joint of the upper tower column (21) and the lower tower column (22) of the two limbs and are used for supporting the main beam (4);

and the pier column (5) is arranged on the bearing platform (1) and supports the lower cross beam (3).

2. A low-profile pylon according to claim 1, wherein the pier (5) has a horizontal cross-sectional area which decreases progressively from top to bottom.

3. The low-low pylon bridge tower according to claim 1, wherein a first support (6) is arranged between the lower cross beam (3) and the abutment (5).

4. A low-low pylon according to claim 3, wherein the first support (6) comprises:

a bottom plate (61) with a groove at the top, wherein the bottom plate (61) is arranged at the top of the pier column (5);

and the bottom of the top plate (62) is provided with a lug which can slide along the transverse bridge in the groove, and the top plate (62) is arranged at the bottom of the lower transverse beam (3).

5. The low-profile pylon according to claim 4, wherein the bottom of the bumps and the bottom of the grooves are each provided with a mirror plate.

6. The low-profile pylon according to claim 4, wherein the bottom plate (61) and top plate (62) are bolted to the pier (5) and lower cross-beam (3), respectively.

7. A low-low pylon according to claim 1, characterized in that the top of the lower cross beam (3) is provided with a damper (7) for limiting the movement of the main beam (4) in the longitudinal bridge direction.

8. A low-low pylon bridge according to claim 1, wherein a second abutment (8) is provided between the lower pylon (22) and the lower cross beam (3).

9. The low-low tower bridge tower according to claim 1, wherein the tower column (2), the lower cross beam (3) and the pier column (5) are all hollow box structures.

10. A method of constructing a low-profile pylon according to claim 1, comprising the steps of:

pouring a bearing platform (1), and pouring the bottoms of the lower tower column (22) and the pier column (5) by turning over a mould;

the climbing form is used for pouring the rest parts of the lower tower column (22) and the pier column (5);

a bracket is arranged between the lower tower column (22) and the pier column (5), a lower cross beam (3) is poured, and the lower cross beam (3) is tensioned for prestress;

and (3) removing the bracket, and pouring an upper tower column (21) by using the climbing form.