Bridge structure provided with pre-pressing system and hanging basket pre-pressing construction method

Abstract

The application discloses a bridge structure provided with a pre-pressing system and a hanging basket pre-pressing construction method, and relates to the technical field of bridge construction. The device comprises a bridge structure provided with a pre-pressing system, which comprises a No.0 block arranged on the top of a pier of the bridge; a pre-pressing counterforce frame arranged on the bottom plate and the middle cross beam of the No.0 block; and a part of the pre-pressing counterforce frame located on the jacking-up piece of the bottom die of the hanging basket assembly and arranged between the bottom surface of the counterforce frame and the bottom die of the hanging basket assembly. In the embodiment of the application, the hanging basket counterforce frame is arranged on the No.0 bottom die of the pier top, so that the erection of the hanging basket counterforce frame is no longer affected by the position and material of the web plate of the pier top.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and in particular to a bridge structure provided with a preloading system and a hanging basket preloading construction method. Background Art

[0002] Currently, prestressed concrete structures are mostly used in the construction of large and medium-span bridges. Their beam cross-sections are generally single-box single-chamber or single-box multi-chamber structures. They are easy to cantilever cast-in-place construction with a hanging basket. They have the characteristics of large span, simple construction, and short construction period. During the cantilever construction process, the hanging basket bears the entire weight of the construction equipment and the newly poured segmental concrete. The size of its load-bearing capacity and the amount of elastic deformation are directly related to the safety of the construction and the control of the structural line shape. In order to test whether the quality of the hanging basket meets the design requirements, find weak links for reinforcement, and eliminate the inelastic deformation of the hanging basket structure, it is generally necessary to conduct a prestressing test on the hanging basket under the design load. The prestressing test methods include: pile load prestressing method and reaction frame prestressing method. The reaction frame prestressing method has gradually replaced the traditional pile load prestressing method due to its advantages such as simple operation, and has become the preferred method for hanging basket prestressing tests on more and more hanging basket cast-in-place bridges.

[0003] In the reaction frame preloading method, the reaction frame structure mostly chooses to embed embedded parts on the 0# block web, and then weld the reaction frame rods to the 0# block web, and realize the preloading of the hanging basket through the jack at the bottom of the reaction frame. However, the installation of the reaction frame rods requires the installation of embedded parts in the concrete as a connecting mechanism. However, some special bridge types no longer use concrete webs, such as corrugated steel webs instead of concrete webs. Corrugated steel webs, as steel structures, cannot have pre-embedded connecting parts, which also means that the web position no longer has the space conditions for installing the hanging basket preloading reaction frame. Summary of the Invention

[0004] In view of the defects existing in the prior art, the present invention provides a bridge structure provided with a preloading system, comprising:

[0005] Block 0, which is located on the top of the bridge pier;

[0006] The pre-compression reaction frame is arranged on the bottom plate and the middle transverse partition of the No. 0 block, and the pre-compression reaction frame is located on the bottom mold of the hanging basket assembly.

[0007] A jacking member is arranged between the bottom surface of the reaction frame and the bottom mold of the hanging basket assembly.

[0008] In some embodiments, the pre-compression reaction frame includes:

[0009] A first connecting rod is vertically mounted on the bottom plate of the pier top;

[0010] The second connecting rod is arranged on the base plate, and the second connecting rod extends along the longitudinal bridge direction to the bottom mold of the hanging basket assembly. The second connecting rod is connected to the first connecting rod through a third connecting rod, and the lifting member is arranged at the bottom of the second connecting rod.

[0011] In some embodiments, a stiffening rod is provided between the second connecting rod and the third connecting rod.

[0012] In some embodiments, the bottom plate of the block No. 0 is tilted along the longitudinal bridge direction, and embedded parts perpendicular to the surface of the bottom plate are embedded in the bottom plate, and the embedded parts extend out of the bottom plate and are connected to the first connecting rod.

[0013] In some embodiments, the bridge structure further includes: a fourth connecting rod, which is assembled on the middle transverse partition of the block No. 0, and the fourth connecting rod extends along the longitudinal bridge direction until it is connected to the first connecting rod.

[0014] In some embodiments, a distribution beam is provided between the lifting member and the bottom mold.

[0015] On the other hand, a hanging basket preloading construction method is provided, comprising the following steps:

[0016] Install multiple lifting parts at preset points on the bottom mold of the erected hanging basket assembly and install a pre-compression reaction frame on the No. 0 block;

[0017] An observation bracket is set up around the hanging basket assembly and an observation point is calibrated, wherein the observation bracket is provided with a level;

[0018] The lifting member is controlled to load the bottom mold multiple times, and the level meter is used to monitor and record the deformation of the bottom mold after each loading.

[0019] In some embodiments, setting up observation brackets around the hanging basket assembly and calibrating observation points includes:

[0020] Preset points are marked on the base mold, and according to the preset points, 5 rows of observation points are set on the observation bracket along the transverse direction of the bridge, and 2 rows of observation points are set along the longitudinal direction of the bridge.

[0021] In some embodiments, controlling the lifting member to load the bottom mold multiple times includes:

[0022] The lifting member is controlled to gradually increase the load, and the load is kept stable for 30 minutes after the last loading.

[0023] In some embodiments, controlling the lifting member to gradually increase the load includes:

[0024] The lifting member is controlled to load step by step, and the load is increased by 20% of the total load each time.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] (1) The hanging basket reaction frame in the embodiment of the present invention is arranged on the bottom plate of block No. 0 and the middle cross beam of the pier top, so that the installation of the hanging basket reaction frame is no longer affected by the position and material of the web of the pier top.

[0027] (2) The top of the hanging basket reaction frame in the embodiment of the present invention is connected to the middle transverse partition to transfer the lateral load on the top of the reaction frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. 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 any creative work.

[0029] Figure 1 It is a front view of the preloading system in an embodiment of the present invention;

[0030] Figure 2 2. It is a front view of a pre-compression reaction frame in an embodiment of the present invention;

[0031] Figure 3 2 is a front view of the observation system in an embodiment of the present invention.

[0032] In the figure: 1. Prestressing reaction frame; 11. First connecting rod; 12. Second connecting rod; 13. Third connecting rod; 14. Fourth connecting rod; 15. Stiffening rod; 2. Lifting part; 3. Block No. 0; 31. Bottom plate; 32. Middle cross partition; 4. Hanging basket assembly; 41. Bottom form; 5. Web plate; 6. Rear view point; 7. Observation point; 8. Embedded parts; 9. Observation bracket. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Figure 1 and Figure 2As shown, in order to solve the problem in the related art that the installation of the hanging basket preloading system is affected by the material of the bridge web 5, the present application provides a bridge preloading system, which includes: block 0 3, jacking piece 2

[0035] Block No. 0 3 is arranged on the top of the pier of the bridge; the prestressing reaction frame 1 is used to be assembled on the bottom plate 31 and the middle cross partition 32 of the block No. 0 3; the jacking part 2 is arranged between the bottom surface of the prestressing reaction frame 1 and the bottom mold 41 of the hanging basket assembly 4.

[0036] It is worth noting that the cross-section of the base plate 31 is large, and there is enough space to set up multiple embedded parts 8 to fix the preload reaction frame 1. The base plate 31 of block No. 0 3 is tilted along the longitudinal bridge direction, and the base plate 31 is pre-embedded with embedded parts 8 perpendicular to the surface of the base plate 31. The embedded parts 8 extend out of the base plate 31 and are connected to the first connecting rod 11.

[0037] Preferably, the top of the pre-compression reaction frame 1 is connected to the middle transverse partition 32 of the No. 0 block 3 through a fourth connecting rod 14.

[0038] It can be understood that the top of the prestressing reaction frame 1 is connected to the middle transverse partition 32, which can effectively transfer the lateral load on the top of the prestressing reaction frame 1, reduce the bending stress at the bottom of the first connecting rod 11 to meet the strength design value requirements of conventional steel Q235B.

[0039] In some embodiments, a total of eight preload reaction frames 1 are used in the preload test, with four on each of the large and small mileage preload frames. To better simulate the load distribution during actual construction, the jacking member 2 is positioned at the center of gravity of the 2# segment load, which carries the largest total construction load. A jack can be used as the jacking member 2.

[0040] In some embodiments, a distribution beam is provided between the jacking member 2 and the bottom formwork 41, and the distribution beam is arranged along the transverse bridge direction. The jacking member 2 is supported on the distribution beam during jacking, and the reaction force applied by the jacking member 2 is transmitted to the bottom formwork 41 of the hanging basket in the form of a linear load. The bottom basket longitudinal beam then transmits the load to the front, middle and rear bottom beams of the hanging basket assembly 4, forming a layer-by-layer distribution and transmission of the counter pressure, so that the stress state of the bottom beam of the hanging basket is basically consistent with that during actual construction.

[0041] Specifically, the preload reaction frame 1 includes: a first connecting rod 11, a second connecting rod 12 and a third connecting rod 13; wherein,

[0042] The first connecting rod 11 is used to pass through the bottom plate 31 on the pier top in the vertical direction; the second connecting rod 12 is used to pass through the bottom plate 31 along the longitudinal bridge direction. The second connecting rod 12 is connected to the first connecting rod 11 through the third connecting rod 13, and the jacking member 2 is arranged at the bottom of the second connecting rod 12.

[0043] Preferably, if Figure 2 As shown, a stiffening rod 15 is provided between the second connecting rod 12 and the third connecting rod 13. Another stiffening rod 15 is also provided between the first connecting rod 11 and the fourth connecting rod 14.

[0044] It is understandable that the embedded part 8 can use a 20mm thick Q235B steel plate as an anchor plate, and each anchor plate is provided with 4 φ32mm PSB785 finely rolled threaded steel bars as anchor bars, with an embedded depth of 500mm.

[0045] Preferably, the first connecting rod 11 is vertically mounted on the bottom plate 31 of the pier top. The second connecting rod 12 is mounted on the bottom plate 31 and extends along the longitudinal bridge direction to the bottom mold 41 of the hanging basket assembly 4. The second connecting rod 12 is connected to the first connecting rod 11 via a third connecting rod 13, and the lifting member 2 is located at the bottom of the second connecting rod 12. The fourth connecting rod 14 is mounted on the middle transverse partition 32 of the No. 0 block 3 and extends along the longitudinal bridge direction until it is connected to the first connecting rod 11.

[0046] On the other hand, the present application provides a hanging basket preloading method, which includes the following steps:

[0047] S1. Install multiple lifting members 2 at preset points on the bottom mold 41 of the completed hanging basket assembly 4.

[0048] After the asynchronous hanging basket is installed, adjust the bottom formwork elevation of the hanging basket to keep it at the same elevation in the transverse direction of the bridge. Lift the distribution beam and place it in the designed position, then place the eight jacking pieces 2 in sequence. The layout point of the jacking piece 2 and the distribution beam is the center of gravity of the heaviest suspended casting segment, and the center of the jacking piece 2 is aligned with the center line of the preload reaction frame 1 and the distribution beam.

[0049] S2. Set up the pre-compression reaction frame 1 and the observation bracket 9.

[0050] After the jacking member 2 is placed, the first connecting rod 11 , the second connecting rod 12 , the third connecting rod 13 and the fourth connecting rod 14 are welded to the embedded member 8 in sequence, and the stiffening rod 15 is also welded.

[0051] Specifically, after the reaction frame is installed, the observation points (402) are drawn on the bottom mold with red paint and numbered, such as Figure 3 As shown, there are 5 rows of single-side hanging basket observation points along the transverse direction of the bridge and 2 rows along the longitudinal direction of the bridge, for a total of 20. In addition, an elevation backsight point 6 is set on the bottom plate 31 of block 3 of block 0 and marked with red paint. For the convenience of observation, a single box room is set with an elevation backsight point, for a total of 4.

[0052] S3. Preload and observation.

[0053] Before starting preloading, perform a routine inspection of the already mounted gantry's connections. Verify the welds between the various members of the preloading reaction frame 1 and reinforce any defects. Weld stiffening plates to areas subject to significant stress. Check the relative position of the jacking member 2 and the preloading reaction frame 1 to ensure the center of the jacking member 2 is aligned with the center of the second connecting rod 12.

[0054] Preloading: Eight jacks simultaneously load the basket. To better simulate the loading process of the basket during actual concrete pouring and ensure the safety and stability of the basket structure, loading is divided into six levels, each level of 20% of the total load, to minimize uneven and asymmetric loading of the baskets on both sides of the T-structure. After each level of loading, there is a 10-minute pause. The next loading step is performed after the deformation of the basket stabilizes. After the final loading step, the load is stabilized for 30 minutes, and then unloading is carried out in stages.

[0055] Deformation Observation: After controlling the preload reaction frame 1 to 40%, 80%, 100%, and 120%, and after the basket deformation stabilizes, use two levels to observe the deformation of the basket base formwork on both sides. During observation, first observe the elevation at the backsight point 6, then measure the elevations of each observation point 7. The difference between the two values ​​is the vertical deformation value of the basket base formwork.

[0056] In summary, the basket reaction frame in this embodiment of the present invention is installed on the No. 0 bottom plate and the center crossbeam at the pier top, making its installation independent of the position and material of the pier top web. The top of the basket reaction frame in this embodiment of the present invention is connected to the center crossbeam, effectively transferring the top lateral load and reducing the stress of the reaction frame structure.

[0057] In the description of this application, it should be noted that the terms "upper" and "lower" and the like 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 this application and simplifying the description, and do not indicate or imply 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 this 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 an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0058] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any 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 comprising 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, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0059] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A bridge structure provided with a preloading system, characterized in that: include: Block 0 (3), which is located on the top of the bridge pier; A pre-compression reaction frame (1) is assembled on the bottom plate (31) and the middle transverse partition (32) of the No. 0 block (3), and the pre-compression reaction frame (1) is partially located on the bottom mold (41) of the hanging basket assembly (4); A lifting member (2) is provided between the bottom surface of the pre-compression reaction frame (1) and the bottom mold (41) of the hanging basket assembly (4); The prestressed reaction frame (1) comprises: a first connecting rod (11) and a second connecting rod (12); wherein the first connecting rod (11) is assembled on the bottom plate (31) of the pier top in a vertical direction; the second connecting rod (12) is assembled on the bottom plate (31), and the second connecting rod (12) extends along the longitudinal bridge direction to the bottom mold (41) of the hanging basket assembly (4); the second connecting rod (12) is connected to the first connecting rod (11) through a third connecting rod (13), and the lifting member (2) is arranged at the bottom of the second connecting rod (12); A fourth connecting rod (14) is assembled on the middle transverse partition (32) of the No. 0 block (3), and the fourth connecting rod (14) extends along the longitudinal bridge direction until it is connected to the first connecting rod (11).

2. The bridge structure according to claim 1, wherein: A stiffening rod (15) is provided between the second connecting rod (12) and the third connecting rod (13).

3. The bridge structure according to claim 1, wherein: The bottom plate (31) of the block No. 0 (3) is tilted along the longitudinal bridge direction, and an embedded part (8) perpendicular to the surface of the bottom plate (31) is embedded in the bottom plate (31), and the embedded part (8) extends out of the bottom plate (31) and is connected to the first connecting rod (11).

4. The bridge structure according to claim 1, wherein: A distribution beam is provided between the lifting member (2) and the bottom mold (41).

5. A method for preloading a bridge structure using a hanging basket as claimed in claim 1, characterized in that: The following steps are involved: Installing a plurality of lifting members (2) at preset points on the bottom mold (41) of the completed hanging basket assembly (4) and installing a pre-compression reaction frame (1) on the No. 0 block (3); An observation bracket (9) is set up around the hanging basket assembly (4) and an observation point is calibrated, and a level is provided on the observation bracket (9); The lifting member (2) is controlled to load the bottom mold (41) of the hanging basket assembly (4) multiple times, and the level is used to monitor and record the deformation of the bottom mold (41) after each loading.

6. The hanging basket preloading construction method according to claim 5, characterized in that: The method of setting up observation brackets (9) around the hanging basket assembly (4) and calibrating observation points includes: Preset points are marked on the bottom mold (41), and according to the preset points, five rows of observation points are set on the observation bracket (9) along the transverse direction of the bridge, and two rows of observation points are set along the longitudinal direction of the bridge.

7. The hanging basket preloading construction method according to claim 5, characterized in that: The controlling the lifting member (2) to load the bottom mold (41) multiple times includes: controlling the lifting member (2) to gradually increase the load, and maintaining a stable load for 30 minutes after the last loading.

8. The hanging basket preloading construction method according to claim 7, characterized in that: The controlling of the lifting member (2) to gradually increase the load comprises: controlling the lifting member (2) to load step by step, with each loading increasing the load by 20% of the total load.

Images