A low lower tower bridge tower and construction method

Abstract

The invention discloses a low-rise bridge tower with lower tower columns and a construction method, and relates to the technical field of bridge engineering. The low-rise bridge tower with lower tower columns comprises: a cap; two tower columns, which are symmetrically arranged on the cap, each tower column comprises an upper tower column and a lower tower column, the lower tower columns of the two limbs are inclined outwards along the cross bridge to set an angle, and the tops are respectively connected to the bottoms of the upper tower columns of the two limbs, and the tops of the upper tower columns of the two limbs are connected together; a lower cross beam, whose two ends are respectively arranged at the connection between the upper tower columns of the two limbs and the lower tower columns, and are used to support the main beam; a pier column, which is arranged on the cap and supports the lower cross beam. The rigidity of the lower cross beam is increased, so that part of the load borne by the lower cross beam is transferred to the pier column, the load borne by the tower column is dispersed, and the force of the tower column is improved. The problem that the lower cross beam and the lower tower column produce a frame effect when the lower cross beam is close to the tower bottom due to the limitation of the terrain and the bridge deck elevation in the prior art is solved, which reduces the application efficiency of the prestress of the cross beam and increases the design difficulty.

Description

Technical Field

[0001] The invention relates to the technical field of bridge engineering, and in particular to a low lower tower column bridge tower and a construction method. Background Art

[0002] As the main load-bearing member of the long-span cable-stayed bridge and suspension bridge, the bridge tower is subjected to compression and bending, and includes the upper tower column, middle tower column, lower tower column, upper crossbeam, lower crossbeam and other structures. As an important part of the main tower, the crossbeam has three functions: first, the crossbeam increases the overall stability of the bridge tower; second, the lower crossbeam provides installation space for the first bearing, damper and other force transmission devices; third, the lower crossbeam transmits part of the bridge deck load to the tower column through the first bearing, damper and other devices.

[0003] The lower cross beams are mostly made of prestressed concrete structure. Under extreme working conditions, the bridge tower cross beams are subjected to large shear forces, bending moments and torques. During the design, it is difficult to meet the requirements for bending bearing capacity, shear bearing capacity, torsional bearing capacity and crack resistance.

[0004] In the prior art, the design requirements are generally met by increasing the height and reinforcement ratio of the beam. When the lower beam is close to the tower bottom due to the terrain and bridge deck elevation restrictions, the lower beam and the lower tower column produce a frame effect, which reduces the application efficiency of the beam prestressing and increases the design difficulty. Summary of the invention

[0005] In view of the defects existing in the prior art, the object of the present invention is to provide a low lower tower column bridge tower and a construction method, which can solve the defects in the prior art.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0007] On the one hand, the present invention provides a low lower tower bridge tower, comprising:

[0008] platform;

[0009] Two-limb tower columns are symmetrically arranged on the pedestal, and each limb of the tower column includes an upper tower column and a lower tower column. The lower tower columns of the two limbs are inclined outward along the cross bridge to set an angle, and the tops are respectively connected to the bottoms of the upper tower columns of the two limbs, and the tops of the upper tower columns of the two limbs are connected together;

[0010] The lower cross beam, both ends of which are respectively arranged at the connection between the upper tower column and the lower tower column of the two limbs, is used to support the main beam;

[0011] A pier column is arranged on the cap and supports the lower cross beam.

[0012] In some optional solutions, the horizontal cross-sectional area of ​​the pier gradually decreases from top to bottom.

[0013] In some optional solutions, a first support is provided between the lower cross beam and the pier.

[0014] In some optional solutions, the first support includes:

[0015] A bottom plate, the top of which is provided with a groove, and the bottom plate is arranged on the top of the pier column;

[0016] The top plate has a protrusion at the bottom thereof which can slide in the groove along the transverse bridge direction, and the top plate is arranged at the bottom of the lower cross beam.

[0017] In some optional solutions, the bottom of the protrusion and the bottom of the groove are both provided with a mirror steel plate.

[0018] In some optional solutions, the bottom plate and the top plate are respectively connected to the pier and the lower cross beam by bolts.

[0019] In some optional solutions, a damper is provided on the top of the lower cross beam for limiting the movement of the main beam along the longitudinal bridge direction.

[0020] In some optional solutions, a second support is provided between the lower tower column and the lower cross beam.

[0021] In some optional solutions, the tower column, lower cross beam and pier column are all hollow box structures.

[0022] On the other hand, the present invention also provides a method for constructing a low-rise lower-pylon bridge tower, which is used to construct the above-mentioned low-rise lower-pylon bridge tower, and comprises the following steps:

[0023] Cast the cap, and cast the lower tower column and the bottom of the pier column by turning the mold;

[0024] Use climbing formwork to cast the remaining parts of the lower tower column and pier column;

[0025] A bracket is arranged between the lower tower column and the pier column, the lower cross beam is cast, and the prestressing force of the lower cross beam is tensioned;

[0026] Remove the bracket and cast the upper tower column using climbing formwork.

[0027] Compared with the prior art, the advantages of the present invention are: the present invention provides support for the lower crossbeam at the connection between the upper tower column and the lower tower column of the two-limb tower column through the pier column arranged on the pedestal. The rigidity of the lower crossbeam is increased, so that part of the load borne by the lower crossbeam is transferred to the pier column, the load borne by the tower column is dispersed, the force of the tower column is improved, and the problem that the lower crossbeam and the lower tower column produce a frame effect when the lower crossbeam is close to the tower bottom due to the limitation of the terrain and the bridge deck elevation in the prior art is solved, which reduces the application efficiency of the prestress of the lower crossbeam and increases the design difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 It is a schematic structural diagram of a low lower tower column bridge tower in an embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of the vertical arrangement of multiple supports of the cross beam under the bridge tower in an embodiment of the present invention;

[0031] Figure 3 This is a schematic structural diagram of the first support from a longitudinal bridge perspective in an embodiment of the present invention;

[0032] Figure 4 This is a schematic structural diagram of the second support from a longitudinal bridge perspective in an embodiment of the present invention;

[0033] Figure 5 It is a structural schematic diagram of a pier column in an embodiment of the present invention;

[0034] Figure 6 A horizontal cross-sectional schematic diagram of a pier column in an embodiment of the present invention;

[0035] Figure 7 It is a top view schematic diagram of the arrangement of the first support and the second support on the lower cross beam in an embodiment of the present invention;

[0036] Figure 8 It is a mechanical schematic diagram of the lower cross beam after forming a bridge in an embodiment of the present invention;

[0037] Fig. 9 It is a mechanical schematic diagram of the prestressing stage of the lower cross beam construction process in an embodiment of the present invention;

[0038] Fig.10 It is a schematic diagram of the process of the construction method of the low lower tower column bridge tower in the embodiment of the present invention;

[0039] In the figure: 1, pedestal; 2, tower column; 21, upper tower column; 22, lower tower column; 3, lower cross beam; 4, main beam; 5, pier column; 6, first bearing; 61, bottom plate; 62, top plate; 7, damper; 8, second bearing. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0041] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0042] like Figure 1 As shown, the present invention provides a low lower tower column bridge tower, characterized in that it includes:

[0043] Platform 1;

[0044] Two-limb tower columns 2 are symmetrically arranged on the cap 1, and each limb tower column 2 includes an upper tower column 21 and a lower tower column 22. The lower tower columns 22 of the two limbs are inclined outward along the cross bridge to set an angle, and the tops are respectively connected to the bottoms of the upper tower columns 21 of the two limbs, and the tops of the upper tower columns 21 of the two limbs are connected together;

[0045] The lower cross beam 3, both ends of which are respectively arranged at the connection between the upper tower column 21 and the lower tower column 22 of the two limbs, is used to support the main beam 4;

[0046] The pier column 5 is arranged on the cap 1 and supports the lower cross beam 3 .

[0047] In this embodiment, the pier 5 provided on the cap 1 provides support for the lower cross beam 3 connected to the connection between the upper tower column 21 and the lower tower column 22 of the two-limb tower column 2. The rigidity of the lower cross beam 3 is increased, so that part of the load borne by the lower cross beam 3 is transferred to the pier 5, the load borne by the tower column 2 is dispersed, the force of the tower column 2 is improved, and the problem that the lower cross beam 3 and the lower tower column 22 produce a frame effect when the lower cross beam 3 is close to the tower bottom due to the limitation of the terrain and the bridge deck elevation in the prior art is solved, which reduces the application efficiency of the prestress of the lower cross beam 3 and increases the design difficulty.

[0048] like Figure 2 , Figure 5 and Figure 6 As shown, in some optional embodiments, the horizontal cross-sectional area of ​​the pier 5 gradually decreases from top to bottom.

[0049] In this embodiment, the top section of the pier column 5 is large, which is used to provide sufficient supporting surface for the lower cross beam 3. The structural form of large top and small bottom saves the amount of concrete and reduces the cost under the premise of meeting the force.

[0050] In some optional embodiments, a first support 6 is provided between the lower cross beam 3 and the pier 5 .

[0051] In this embodiment, the first support 6 is provided to better support the lower cross beam 3 .

[0052] like Figure 3 As shown, in some optional embodiments, the first support 6 includes:

[0053] A bottom plate 61, the top of which is provided with a groove, and the bottom plate 61 is arranged on the top of the pier 5;

[0054] The top plate 62 has a protrusion at its bottom that can slide in the groove along the horizontal bridge direction. The top plate 62 is arranged at the bottom of the lower cross beam 3.

[0055] In this embodiment, the structure of the first support 6 can prevent the lower cross beam 3 from being displaced in the longitudinal direction of the bridge when the prestress is tensioned during the construction stage, and transmit the longitudinal force of the main beam under the action of wind load or earthquake load during the bridge operation stage.

[0056] In some optional embodiments, the bottom of the protrusion and the bottom of the groove are both provided with a mirror steel plate.

[0057] In this embodiment, the mirror steel plate is a stainless steel plate, which is welded to the bottom of the protrusion and the bottom of the groove. The anti-slip coefficient between the two mirror steel plates is not greater than 0.1, so that the top plate 62 and the bottom plate 61 can slide in the transverse direction.

[0058] In some optional embodiments, the bottom plate 61 and the top plate 62 are respectively connected to the pier 5 and the lower beam 3 by bolts.

[0059] In this embodiment, the stability of the connection between the bottom plate 61 and the top plate 62 and the pier 5 and the lower cross beam 3 is ensured by bolt connection.

[0060] In some optional embodiments, a damper 7 for limiting the movement of the main beam 4 along the longitudinal direction of the bridge is provided on the top of the lower cross beam 3 .

[0061] In some optional embodiments, a second support 8 is provided between the lower tower column 22 and the lower cross beam 3 .

[0062] like Figure 4 As shown, in this embodiment, the second support 8 includes a first support top plate connected to the lower tower column 22 and a first support bottom plate connected to the lower cross beam 3, and the first support top plate and the first support bottom plate can slide in the transverse bridge direction and the longitudinal bridge direction through the mirror steel plate. Limiting blocks are set on both sides of the longitudinal bridge direction of the first support bottom plate to prevent excessive longitudinal bridge displacement when prestressing.

[0063] like Figure 7 The figure shows a schematic top view of the arrangement of the first support and the second support on the lower cross beam 3 .

[0064] The lower cross beam 3 after the bridge is completed is taken as the isolated body for analysis. The effect of the tower column 2 on the lower cross beam 3 can be simplified to the fixed first bearing, the effect of the pier column 5 on the lower cross beam 3 can be simplified to the movable hinge first bearing, and the effect of the main beam 4 on the lower cross beam 3 can be simplified to the load F, such as Figure 8 As shown. The span of the lower cross beam 3 is greatly reduced, which increases the bending, shear and torsional rigidity of the lower cross beam 3. Most of the load transferred from the main beam 4 to the lower cross beam 3 is also directly borne by the pier 5, and the load borne by the lower cross beam 3 is reduced.

[0065] In some optional embodiments, the tower column 2, the lower cross beam 3, and the pier column 5 are all hollow box structures.

[0066] In this embodiment, the hollow box structure has good stress-bearing performance, reduces the deadweight of the tower column, and saves the amount of concrete.

[0067] like Fig.10 As shown, on the other hand, the present invention also provides a method for constructing a low lower tower column bridge tower, which is used to construct the above-mentioned low lower tower column bridge tower, comprising the following steps:

[0068] S1: Casting the cap 1, and casting the lower tower column 22 and the bottom of the pier column 5 by turning the mold.

[0069] S2: Cast the remaining parts of the lower tower column 22 and the pier column 5 using climbing formwork.

[0070] S3: a bracket is arranged between the lower tower column 22 and the pier column 5, the lower cross beam 3 is cast, and the prestress of the lower cross beam 3 is tensioned.

[0071] In this embodiment, a second support 8 is provided at the top of the lower tower column 22 segment to isolate the lower tower column 22 from the lower cross beam 3, so that the prestress is borne by the lower cross beam 3, thereby reducing the influence of the prestress on the lower tower column 22. The mechanical schematic diagram is shown in FIG. Fig. 9 shown.

[0072] S4: Remove the bracket and cast the upper tower column 21 using a climbing formwork.

[0073] In this embodiment, after prestress is applied to the lower cross beam 3, the lower cross beam 3 and the lower tower column 22 are connected as a whole, and then the upper tower column 21 is cast, so as to reduce the shrinkage creep effect of concrete and reduce the risk of concrete cracking.

[0074] Taking a cross-sea bridge with a main span of 688m 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 beam is 31m. The bridge adopts a longitudinal restraint system, the tower and beam are separated, the vertical first support is set between the tower and beam, and a longitudinal restraint is set at one of the towers. The basic wind speed at the bridge site is 46.5m / s; the seismic design is carried out according to the two-stage horizontal fortification.

[0075] The stress conditions of the lower beams supported by piers and those not supported by piers under strong winds and earthquakes are compared, as shown in Table 1:

[0076] Table 1

[0077] The structure uses piers to support the lower beam. Under strong winds, the maximum positive bending moment of the beam becomes 0.93 times of the original, and the maximum negative bending moment becomes 0.93 times of the original. Under earthquakes, the maximum bending moment of the beam becomes 0.86 times of the original, and the minimum bending moment becomes 0.89 times of the original. The bending moment of the lower beam supported by piers is reduced.

[0078] The stress conditions at the bottom of the lower tower column under strong wind and earthquake are compared with those without piers supporting the lower beam, as shown in Table 2:

[0079] Table 2

[0080] The structure uses piers to support the lower beam. Under strong winds, the maximum positive bending moment at the bottom of the tower becomes 0.85 times the original, and the maximum negative bending moment becomes 0.85 times the original. Under earthquakes, the maximum bending moment at the bottom of the tower becomes 0.77 times the original, and the minimum bending moment becomes 0.78 times the original. After using piers to support the lower beam, the bending moment at the bottom of the tower is reduced.

[0081] Compared with the traditional construction method, the impact of this new construction method on the lower beam and lower tower column is shown in Table 3:

[0082] Table 3

[0083]

[0084] By adopting the construction method of the present invention, the application efficiency of 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 the traditional method, and the bending moment of the lower tower column is greatly reduced.

[0085] The measure of setting up temporary supports before prestressing the lower crossbeam can improve the application efficiency of the prestress of the lower crossbeam and reduce the number of prestressed steel strands. At the same time, it also effectively reduces the bending moment caused by the shrinkage and creep of the tower column concrete and reduces the risk of concrete cracking.

[0086] In summary, the present invention sets piers under the lower crossbeam to provide support, which reduces the span of the lower crossbeam, increases the rigidity of the lower crossbeam, and enables the lower crossbeam to withstand greater shear force, bending moment, and torque; compared with the unsupported lower crossbeam, the cross-sectional size of the lower crossbeam is smaller. Part of the load borne by the lower crossbeam is directly transferred to the piers through the support, dispersing the load borne by the tower columns on both sides and improving the force of the tower columns. After the prestress is applied to the lower crossbeam, the lower crossbeam and the lower tower column are connected as a whole to reduce the shrinkage creep effect of the concrete and reduce the risk of concrete cracking. The erection of a cast-in-place bracket for the lower crossbeam is avoided, and only a few temporary brackets need to be set between the piers and the tower columns, which is convenient for construction. The overall stability of the bridge tower is improved.

[0087] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0088] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0089] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A low lower tower bridge tower, characterized in that: include: Platform (1); Two-limb tower columns (2) are symmetrically arranged on the support platform (1), each limb of the tower column (2) comprises an upper tower column (21) and a lower tower column (22), the lower tower columns (22) of the two limbs are inclined outwardly along the cross bridge at a set angle, and the tops are respectively connected to the bottoms of the upper tower columns (21) of the two limbs, and the tops of the upper tower columns (21) of the two limbs are connected together; A lower cross beam (3), both ends of which are respectively arranged at the connection between the upper tower column (21) and the lower tower column (22) of the two limbs, and are used to support the main beam (4); A pier column (5) which is arranged on the base (1) and supports the lower crossbeam (3); A first support (6) is provided between the lower cross beam (3) and the pier column (5); The first support (6) comprises: A bottom plate (61) having a groove at the top, wherein the bottom plate (61) is arranged on the top of the pier (5); A top plate (62), the bottom of which is provided with a protrusion capable of sliding in the groove along the transverse bridge direction, and the top plate (62) is arranged at the bottom of the lower cross beam (3); The bottom of the protrusion and the bottom of the groove are both provided with a mirror steel plate; A second support (8) is provided between the lower tower column (22) and the lower cross beam (3); The second support (8) comprises a first support top plate connected to the lower tower column (22) and a first support bottom plate connected to the lower crossbeam (3), and the first support top plate and the first support bottom plate are slidable in the transverse bridge direction and the longitudinal bridge direction via a mirror steel plate.

2. The low lower tower bridge tower according to claim 1, characterized in that: The horizontal cross-sectional area of ​​the pier (5) gradually decreases from top to bottom.

3. The low lower tower bridge tower according to claim 1, characterized in that: The bottom plate (61) and the top plate (62) are respectively connected to the pier column (5) and the lower cross beam (3) by bolts.

4. The low lower tower bridge tower according to claim 1, characterized in that: A damper (7) for limiting the movement of the main beam (4) along the longitudinal bridge direction is arranged on the top of the lower cross beam (3).

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

6. A method for constructing a low-rise lower-pylon bridge tower, which is used to construct the low-rise lower-pylon bridge tower as claimed in claim 1, characterized in that: The following steps are involved: Casting the cap (1), and casting the lower tower column (22) and the bottom of the pier column (5) by turning the mold; Casting the remaining parts of the lower tower column (22) and the pier column (5) using a climbing formwork; A bracket is arranged between the lower tower column (22) and the pier column (5), a lower cross beam (3) is cast, and a prestressing force is applied to the lower cross beam (3); The bracket is removed and the upper tower column (21) is cast using a climbing formwork.

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