A multi-point synchronous embracing beam dropping method for bridge piers

Abstract

The present invention discloses a multi-point synchronous embracing beam-dropping method for a pier. The method comprises the following steps: a plurality of symmetrical temporary support units are evenly distributed around the pier column of the pier, each temporary support unit is composed of a plurality of rows of steel pipe piles, a lifting and lowering device is arranged on the top of the steel pipe pile, a jack is arranged on the top of each lifting and lowering device, and a jack is arranged between the tops of two symmetrical groups of temporary support units and the jacking support covered on the plurality of jacks is arranged. The present invention avoids direct contact between the jack and the beam body by arranging the jacking support between the jack and the beam body, and can avoid multiple deformation defects of the steel plate of the beam body, thereby avoiding further damage to the beam body during the beam-dropping process. At the same time, the jacking support also has the functions of evenly distributing the load on the beam body and enhancing the synchronous operation of the jacks.

Description

Technical Field

[0001] The invention relates to the field of bridge beam dropping engineering, and in particular to a multi-point synchronous embracing beam dropping method for a bridge pier. Background Art

[0002] Steel structure bridges are widely used in daily transportation. After the steel structure bridge across the river is installed in place, the whole bridge needs to be lowered to realize the conversion of the load-bearing system. It is difficult to deal with adverse stress, control synchronization and control the overall linear posture accuracy during the beam dropping process of large-span steel-concrete composite beams. Therefore, a multi-point synchronous embracing beam dropping device suitable for large-span steel-concrete composite beams is proposed to ensure the structural safety and linear posture controllability during the beam dropping process.

[0003] The prior art discloses a patent document with application number: 201410148642.6, which discloses a solution: "Taking into account that the bottom surface of the beam body and the top of the pier do not meet the requirements for the arrangement of the jacks, it is planned to set up four Φ1000×10mm seamless steel pipe temporary piers near the pier columns, and use channel steels to horizontally weld them in pairs to connect them into a whole. When arranging the temporary piers, avoid the newly built pier columns and ensure that they do not affect the construction of the new project, and arrange jacks on the temporary piers." During the beam lowering process, the jack contacts the steel plate at the bottom of the beam body, which will cause deformation defects in the steel plate. There are only four jacks in the above scheme, and the damage to the bottom of the beam when the beam is dropped is limited. However, in the prior art, there are dozens of jacks for jacking cross-river and cross-sea bridges. The damage to the bottom of the beam will increase accordingly with the increase in the number of jacks, greatly reducing the service life of the beam. Moreover, in the prior art, if the jacking force of the jack is too large when the beam is dropped, the deformation defects at the steel plate will be further deepened, causing greater damage to the steel plate. Therefore, the jacking force is limited. The existing elevation of the jack when dropping the beam is 80mm, and the construction efficiency of dropping the beam cannot be improved.

[0004] In the prior art, the jacks need to bear the load of the beam during the beam lowering process. The pump station supplies oil to multiple jacks through multiple oil circuits. If some of the oil circuits are blocked or a jack leaks oil, the multiple jacks cannot be raised and lowered synchronously, which will cause the beam to deform. If the deformation is serious, it is necessary to stop and replace the deformed steel plate of the beam and inspect the oil circuit and jacks before continuing to work, which greatly reduces the construction efficiency. Summary of the invention

[0005] The present invention provides a beam dropping method that can avoid the bottom of the beam from being damaged and improve the stability of the beam dropping. The specific scheme is as follows:

[0006] A multi-point synchronous embracing beam dropping method for a bridge pier, wherein a spherical support is provided on the top of the pier column, and a beam body is supported on the spherical support, based on a beam dropping device, the beam dropping device comprises:

[0007] The load-bearing support comprises at least four groups of temporary support units surrounding the periphery of the pier and evenly arranged on the axis of the pier, the temporary support units are composed of a plurality of rows of steel pipe piles, the top of the steel pipe piles is a closed structure, and the top of each steel pipe pile is located on the closed structure and is welded with a double-jointed steel base;

[0008] The system conversion mechanism includes a lifting and lowering device and a temporary pier device. The lifting and lowering device includes a plurality of first steel pads, a plurality of first adjustment steel plates and a jack which are stacked on each of the double-piece steel bases in sequence. The four groups of temporary support units are symmetrical to each other, and a top support is connected between each two groups of symmetrical temporary support units. The top support covers the top of each jack on the two groups of temporary support units. The temporary pier device includes a plurality of second steel pads and a plurality of second adjustment steel plates which are stacked on the spherical support in sequence. Both of the two top supports are horizontally aligned with the second adjustment steel plates. Each jack is uniformly controlled by a pump station.

[0009] Monitoring systems, including:

[0010] A plurality of first stress-strain sensors, used for detecting the settlement and displacement of the load-bearing support;

[0011] A plurality of second stress-strain sensors, used for detecting stress changes of the landing gear;

[0012] A plurality of third stress and strain sensors, used to detect stress changes at monitoring points of the beam section;

[0013] The beam dropping method comprises the following steps:

[0014] Step 1: Set up the load-bearing support for the bridge piers at the river crossing position, and build at least four sets of temporary support units evenly arranged along the axis of each pier column.

[0015] Step 2: Arrange the system conversion mechanism, alternately arrange the first steel pads on the double-piece steel base according to the designed number of layers, and place the first adjustment steel plates of different thicknesses on the first steel pads; arrange the second steel pads on the spherical support, and place the second adjustment steel plates of different thicknesses on the second steel pads; the jack is arranged on the first adjustment steel plate and fixedly connected with the top support, and the top support is temporarily welded and fixed to the bottom plate of the steel-concrete composite beam bridge;

[0016] Step 3: Stress and strain sensors are respectively installed at the detection points of the load-bearing bracket, the lifting and lowering device and the beam section, and data is collected and transmitted to monitor the verticality of the beam lowering device, and the beam lowering amplitude is adjusted according to the monitoring results;

[0017] Step 4: After all the welds of the beam body are completed, the beam-dropping load-bearing bracket is preloaded. The jacks at each pier are controlled by the pump station controller. Each jack is lifted synchronously to a certain lifting force (70% of the maximum lifting force of the jack). The lifting force is applied to the beam body so that the beam body begins to be stressed but does not cause vertical displacement. At this time, the round pipe piles and the first steel pads of the beam-dropping load-bearing bracket gradually begin to bear the vertical force. After the stress-strain sensor shows that the preload is stable, the load-bearing bracket is inspected and reinforced;

[0018] Step 5: By adjusting the thickness of the second adjusting steel plate, there is no gap between the spherical bearing and the beam body, and the beam body load is borne by the load-bearing bracket and the pier column;

[0019] Step 6: Monitor the stress and strain of the load-bearing bracket and the beam, start the whole bridge lowering process, pull out the first adjustment steel plate under the jack, lower the total elevation to the preset value, control the jack to lift synchronously through the pump station controller until the beam is completely separated from the spherical support, pull out part of the second adjustment steel plate to lower the total elevation, then the jack will release the pressure synchronously, the whole bridge will be lowered, and the load will be transferred from the load-bearing bracket to the spherical support again;

[0020] Step 7: Repeat the above operation to slowly drop the beam until the second steel pad and the second adjustment steel plate on the side span ball bearing are completely pulled out. After the beam is dropped, remove the beam dropping device.

[0021] Furthermore, the bridge pier is a double-column structure, and the bridge pier includes two columns and a cap beam connected between the tops of the two columns. A pedestal is provided at the bottom of the two columns, and at least four groups of temporary support units are arranged around each pier column.

[0022] Furthermore, the first temporary support unit and the second temporary support unit in the four groups of temporary support units are symmetrically arranged on both sides of the connection end between the pier and the cap beam, and the top support is connected between the tops of the first temporary support unit and the second temporary support unit; the third temporary support unit and the fourth temporary support unit are arranged at the other end of the pier symmetrical to the first temporary support unit and the second temporary support unit, and the top support is provided between the tops of the third temporary support unit and the fourth temporary support unit.

[0023] Furthermore, the top supports are each formed into a grating plate by welding a plurality of H-shaped steels, a first stiffening plate is respectively provided on both sides of the ribs of the H-shaped steel corresponding to the jacks, and two pairs of inverted L-shaped fasteners are provided at the bottom of the top supports corresponding to the top plates of each jack, the two pairs of fasteners are snap-fitted to the edges of both sides of the top plate and fixed by welding, and the top of the top supports is respectively welded and fixed to the bottom of the beam body.

[0024] Furthermore, pile foot embedded parts are respectively provided at the bottom of each steel pipe pile in the abutment of the pier, and the steel pipe piles are welded and fixed to the corresponding pile foot embedded parts; auxiliary pier embedded parts corresponding to each steel pipe pile are provided in the facade of the pier column or the cap beam, and there is a spacing between some steel pipe piles in the third temporary support unit and the fourth temporary support unit located on both sides of the outer end of the pier column and the auxiliary pier embedded parts, and a first reinforcing beam is connected in the spacing, and the first reinforcing beam is an H-shaped steel.

[0025] Furthermore, a cover plate constituting a closed structure is welded to the top of each steel pipe pile, and a double-piece steel base is welded and fixed to the center of the cover plate. The double-piece steel base is assembled from two H-shaped steels, and second stiffening plates are respectively provided on both sides of the ribs of the two H-shaped steels. Pier embedded parts corresponding to each double-piece steel base are respectively provided on the outer facades of the pier column and the cap beam, and the double-piece steel base is welded and fixed to the corresponding pier embedded parts.

[0026] Furthermore, the first steel pad is composed of multiple H-steels stacked in a well-shaped structure, with the H-steels of each layer arranged alternately vertically and horizontally. Each H-steel has a third stiffening plate vertically arranged on both sides of the rib, and the second steel pad has the same structure as the first steel pad.

[0027] Furthermore, the multiple layers of first adjustment steel plates have the same area but different thicknesses, the multiple layers of second adjustment steel plates have the same area but different thicknesses, and both the first adjustment steel plates and the second adjustment steel plates are used for fine-tuning the elevation; each of the jacks is placed centrally on the corresponding first adjustment steel plate.

[0028] Furthermore, a plurality of second reinforcing beams are connected between the first temporary support unit and the second temporary support unit located at the lower part of the cap beam, the second reinforcing beams are H-shaped steels, and the plurality of second reinforcing beams include horizontal and oblique connection postures; a fifth temporary support unit composed of a single steel pipe pile is provided between the third temporary support unit and the fourth temporary support unit, and a plurality of fourth reinforcing beams are connected between the single steel pipe pile and the third temporary support unit and the fourth temporary support unit respectively, the fourth reinforcing beams are H-shaped steels, and the plurality of fourth reinforcing beams are divided into horizontal and oblique settings, and a third reinforcing beam is connected between the double-piece steel base arranged on the top of the fifth temporary support unit and the bottom of the third temporary support unit and the fourth temporary support unit, and the third reinforcing beam is an H-shaped steel.

[0029] Furthermore, the specific plan for building the load-bearing support in step one is: pre-embed the pile foot embedded parts when tying the steel bars at the base, and install the steel pipe piles after the base is cast in concrete and maintained; pre-embed the attached pier embedded parts when tying the steel bars of the pier column, and after the concrete pouring of the pier column is completed, the steel pipe pile connecting pipes and the steel pipe piles are transversely reinforced and connected; after the maintenance of the pier column is completed, the first reinforcing crossbeam is set between the steel pipe piles and the attached pier embedded parts that are partially away from the pier column in the third temporary support unit and the fourth temporary support unit, so as to strengthen the connection between the steel pipe piles and the attached pier embedded parts; trim the upper end of the steel pipe pile to the designed top elevation, and then place the cover plate and the double-piece steel base in sequence.

[0030] Compared with the prior art, the advantages of the present invention are as follows:

[0031] 1. The present invention has the following advantages by arranging a jacking support between the multiple jacks and the beam body. First, the jacking support can prevent the multiple jacks from directly contacting the steel plate at the bottom of the beam body, causing multiple deformation defects on the steel plate at the contact position, thereby avoiding the possibility of damage to the steel plate;

[0032] Furthermore, in the process of beam dropping, there is no deformation defect, so there is no need to consider the damage of the jack to the beam body, and the lifting force of the jack can be applied without restriction. The lifting height of the jack in the present invention can be up to 2 times of the original height, which improves the efficiency of beam dropping construction.

[0033] Furthermore, by setting up the jacking support, even if individual jacks cannot be synchronized, when most jacks rise, the jacking support can drive the jacks that are not burdened with effort to rise synchronously. When most jacks descend, the jacking support will withstand the rising force exerted by the individual jacks and deform (the strength of the jacking support is weaker than the overall strength of the beam). The beam can avoid deformation, and only the oil circuit and damaged jacks need to be inspected, thereby improving construction efficiency.

[0034] 2. The jacking in the present invention also has the function of evenly distributing the load on the beam and enhancing the synchronous operation of the jack.

[0035] 3. The present invention adopts a load-bearing bracket, which not only simplifies the frame structure and facilitates erection, but also effectively improves the overall stability of the load-bearing bracket and ensures the load-bearing performance.

[0036] 4. The present invention adopts a detection system to provide real-time feedback on the deformation of the beam-dropping device and the entire bridge, and makes dynamic adjustments based on the linear posture, stress and strain of the beam body to ensure the safety and controllability of the beam-dropping process.

[0037] 5. The present invention realizes multi-point synchronous lifting and lowering through the control of each pier pump station system, ensures balanced force on the support, and further ensures the safety of the main structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a front view of the beam body, the bridge pier and the beam dropping device of the present invention;

[0039] Figure 2 This is a three-dimensional diagram of the bridge pier;

[0040] Figure 3 for Figure 2 A partial enlarged view of

[0041] Figure 4 This is a top view of the bridge pier;

[0042] Figure 5 It is a schematic diagram of the conversion mechanism structure;

[0043] Figure 6 It is a schematic diagram of the structure where the jack and the jacking support are fixed by fasteners;

[0044] Figure 7 It is a schematic diagram of the arrangement of monitoring points on the load-bearing bracket and the landing gear;

[0045] Figure 8 It is a schematic diagram of the arrangement of multiple stress detection points on each section of the beam body;

[0046] Fig. 9 Schematic diagram of the structure of the system conversion mechanism before and after the beam is dropped;

[0047] Reference numerals:

[0048] 1. Beam; 2. Pier; 3. Cap; 4. Pier column; 5. Spherical bearing; 6. Steel pipe pile; 7. Temporary support unit; 7-1. First temporary support unit; 7-2. Second temporary support unit; 7-3. Third temporary support unit; 7-4. Fourth temporary support unit; 7-5. Fifth temporary support unit; 8. Cap beam; 9. Double-jointed steel base; 9-1; Second stiffening plate; 10. First steel pad; 10-1 Third stiffening plate; 11. First adjustment Section steel plate; 12, jack; 12-1, top plate; 12-2, fasteners; 13, top support; 13-1, first stiffening plate; 14, second steel pad; 15, second adjustment steel plate; 16, pile foot embedded parts; 19, first reinforcing beam; 20, cover plate; 21, second reinforcing beam; 22, first stress-strain sensor; 23, third reinforcing beam; 24, fourth reinforcing beam; 25, second stress-strain sensor; 26, third stress-strain sensor. DETAILED DESCRIPTION

[0049] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0050] Example 1

[0051] like Figure 1 As shown, a multi-point synchronous embracing beam-dropping device for a bridge pier, wherein a spherical support is provided on the top of the pier column of the bridge pier, and a beam body is supported on the spherical support. Specifically, the bridge pier is a double-column structure, and the bridge pier includes two columns and a cap beam connected between the tops of the two columns. A cap is provided at the bottom of the two columns, and at least four groups of temporary support units are arranged around each pier column. The beam-dropping device includes;

[0052] like Figure 2 As shown, the load-bearing support includes at least four groups of temporary support units surrounding the periphery of the pier and evenly arranged on the axis of the pier, the temporary support units are composed of a plurality of rows of steel pipe piles, the number of which is set according to the specific size of the pier, the top of the steel pipe pile is a closed structure, and the top of each steel pipe pile is located on the closed structure and a double-jointed steel base is welded;

[0053] The first temporary support unit and the second temporary support unit of the four groups of temporary support units are symmetrically arranged on both sides of the connection end between the pier and the cap beam, and the first temporary support unit and the second temporary support unit respectively contain at least 4 steel pipe piles; the third temporary support unit and the fourth temporary support unit are arranged at the other end of the pier symmetrical to the first temporary support unit and the second temporary support unit, and the third temporary support unit and the fourth temporary support unit respectively contain at least 3 temporary support units.

[0054] like Figure 4 As shown, pile foot embedded parts are respectively provided at the bottom of each corresponding steel pipe pile in the foundation of the pier, and the steel pipe piles are welded and fixed to the corresponding pile foot embedded parts; auxiliary pier embedded parts corresponding to each steel pipe pile are provided in the facade of the pier column or the cap beam, and there is a spacing between some steel pipe piles in the third temporary support unit and the fourth temporary support unit located on both sides of the outer end of the pier column and the auxiliary pier embedded parts, and a first reinforcing cross beam is connected in the spacing, and the first reinforcing cross beam is an H-shaped steel.

[0055] like Figure 3 and Figure 4 As shown, a cover plate constituting a closed structure is welded to the top of each steel pipe pile, and a double-piece steel base is welded and fixed to the center of the cover plate. The double-piece steel base is assembled from two H-shaped steels, and second stiffening plates are respectively provided on both sides of the ribs of the two H-shaped steels. Pier embedded parts corresponding to each double-piece steel base are respectively provided on the facades of the pier column and the cap beam, and the double-piece steel base is welded and fixed to the corresponding pier embedded parts.

[0056] like Figure 2As shown, a plurality of second reinforcing beams are connected between the first temporary support unit and the second temporary support unit located at the lower part of the cap beam, and the second reinforcing beams are H-shaped steels. The plurality of second reinforcing beams include horizontal and oblique connection postures; a fifth temporary support unit composed of a single steel pipe pile is provided between the third temporary support unit and the fourth temporary support unit, and a plurality of fourth reinforcing beams are connected between the single steel pipe pile and the third temporary support unit and the fourth temporary support unit respectively, and the fourth reinforcing beams are H-shaped steels. The plurality of fourth reinforcing beams are divided into two types: horizontal or oblique settings, and a third reinforcing beam is connected between the double-piece steel base arranged on the top of the fifth temporary support unit and the bottom of the third temporary support unit and the fourth temporary support unit, and the third reinforcing beam is an H-shaped steel.

[0057] like Figure 5 As shown, the system conversion mechanism includes a lifting and lowering device and a temporary pier device. The lifting and lowering device includes multiple layers of first steel pads, multiple layers of first adjustment steel plates and jacks stacked on each of the double-piece steel bases in sequence. The four groups of temporary support units are symmetrical to each other, and each two groups of symmetrical temporary support units are connected with a top support, which covers the top of each jack on the two groups of temporary support units; the temporary pier device includes multiple layers of second steel pads and multiple layers of second adjustment steel plates stacked on the spherical support in sequence, and the two top supports are horizontally aligned with the second adjustment steel plates; each jack is uniformly controlled by the pump station. In the present invention, a total of 26 steel pipe piles are arranged outside the two piers surrounding the pier, and 26 jacks are used to jointly carry out the beam lowering operation on the beam body on the pier.

[0058] The multiple layers of first adjustment steel plates have the same area but different thicknesses, the multiple layers of second adjustment steel plates have the same area but different thicknesses, and both the first adjustment steel plate and the second adjustment steel plate are used for fine-tuning the elevation; each of the jacks is placed centrally on the corresponding first adjustment steel plate.

[0059] like Figure 3 As shown, the first steel pad is composed of multiple H-steels stacked in a well-shaped structure, with the H-steels of each layer arranged alternately vertically and horizontally. Each H-steel has a third stiffening plate vertically arranged on both sides of the rib, and the second steel pad has the same structure as the first steel pad.

[0060] like Figure 3 and Figure 6 The jacking supports are all composed of a plurality of H-shaped steels welded together to form a grating plate, and a first stiffening plate is provided on both sides of the ribs of the H-shaped steel corresponding to the jacks, and two pairs of inverted L-shaped fasteners are provided at the bottom of the jacking supports corresponding to the top plates of each jack, and the two pairs of fasteners are snap-fitted to the edges of both sides of the top plate and fixed by welding, and the top of the jacking supports is respectively welded and fixed to the bottom of the beam body.

[0061] like Figure 7 and Figure 8As shown, the monitoring system comprises:

[0062] A plurality of first stress-strain sensors are arranged in the middle of each steel pipe pile and are used to detect the settlement and displacement of the load-bearing support;

[0063] A plurality of second stress and strain sensors are arranged on the top of each steel pipe pile and are used to detect stress changes of the landing gear;

[0064] A plurality of third stress and strain sensors are arranged at each connection point of the load-bearing bracket on the cross section of the beam body and are used to detect stress changes at monitoring points of the cross section of the beam body.

[0065] Example 2

[0066] like Fig. 9 As shown, a multi-point synchronous embracing beam dropping method for a bridge pier, the beam dropping method comprises the following steps:

[0067] Step 1: Set up the load-bearing support for the bridge piers at the cross-river section, and build at least four groups of temporary support units evenly arranged around the axis of each pier. The specific plan for building the load-bearing support is as follows: when tying the steel bars at the abutment, embed the pile foot embedded parts, and install the steel pipe piles after the concrete is poured into the abutment and curing is completed; when tying the steel bars of the pier, embed the attached pier embedded parts, and after the concrete is poured into the pier, connect the steel pipe piles and strengthen the steel pipe piles transversely. After the pier is cured, set the first reinforcing crossbeam between the steel pipe piles and the attached pier embedded parts that are partly away from the pier in the third temporary support unit and the fourth temporary support unit, so as to strengthen the connection between the steel pipe piles and the attached pier embedded parts; trim the upper end of the steel pipe pile to the designed top elevation, and then place the cover plate and the double-piece steel base in sequence;

[0068] Step 2: Arrange the system conversion mechanism, alternately arrange the first steel pads on the double-piece steel base according to the designed number of layers, and place the first adjustment steel plates of different thicknesses on the first steel pads; arrange the second steel pads on the spherical support, and place the second adjustment steel plates of different thicknesses on the second steel pads; the jack is arranged on the first adjustment steel plate and fixedly connected with the top support, and the top support is temporarily welded and fixed to the bottom plate of the steel-concrete composite beam bridge;

[0069] Step 3: Stress and strain sensors are respectively installed at the detection points of the load-bearing bracket, the lifting and lowering device and the beam section, and data is collected and transmitted to monitor the verticality of the beam lowering device, and the beam lowering amplitude is adjusted according to the monitoring results;

[0070] Step 4: After all the welds of the beam body are completed, the beam-dropping load-bearing bracket is preloaded. The jacks at each pier are controlled by the pump station controller. Each jack is lifted synchronously to a certain lifting force (70% of the maximum lifting force of the jack). The lifting force is applied to the beam body so that the beam body begins to be stressed but does not cause vertical displacement. At this time, the round pipe piles and the first steel pads of the beam-dropping load-bearing bracket gradually begin to bear the vertical force. After the stress-strain sensor shows that the preload is stable, the load-bearing bracket is inspected and reinforced;

[0071] Step 5: By adjusting the thickness of the second adjusting steel plate, there is no gap between the spherical bearing and the beam body, and the beam body load is borne by the load-bearing bracket and the pier column;

[0072] Step 6: Monitor the stress and strain of the load-bearing bracket and the beam, start the whole bridge lowering process, pull out the first adjustment steel plate under the jack, lower the total elevation to the preset value (i.e., the total elevation is reduced by 80mm), control the jack to lift synchronously through the pump station controller until the beam is completely separated from the spherical support, pull out part of the second adjustment steel plate to lower the total elevation (i.e., the total elevation is reduced by 160mm~80mm), then the jacks are depressurized synchronously, the whole bridge is lowered (i.e., the total elevation is reduced by 160mm~80mm), and the load is transferred from the load-bearing bracket to the spherical support again;

[0073] Step 7: Repeat the above operation to slowly drop the beam until the second steel pad and the second adjustment steel plate on the side span ball bearing are completely pulled out. After the beam is dropped, remove the beam dropping device.

[0074] The present invention is described in detail above in conjunction with the embodiments of the accompanying drawings. A person skilled in the art can make various variations of the present invention according to the above description. Therefore, some details in the embodiments should not be construed as limiting the present invention, and the present invention shall be protected by the scope defined by the attached claims.

Claims

1. A multi-point synchronous embracing beam dropping method for a bridge pier, wherein a spherical support is provided on the top of the pier column, and a beam body is supported on the spherical support, based on a beam dropping device, the beam dropping device include: The load-bearing support comprises at least four groups of temporary support units surrounding the periphery of the pier and evenly arranged on the axis of the pier, the temporary support units are composed of a plurality of rows of steel pipe piles, the top of the steel pipe piles is a closed structure, and the top of each steel pipe pile is located on the closed structure and is welded with a double-jointed steel base; The system conversion mechanism includes a lifting and lowering device and a temporary pier device. The lifting and lowering device includes multiple layers of first steel pads, multiple layers of first adjustment steel plates and jacks which are stacked on each of the double-piece steel bases in sequence. The four groups of temporary support units are symmetrical to each other, and each two groups of symmetrical temporary support units are connected with a top support, which covers the top of each jack on the two groups of temporary support units. The temporary pier device includes multiple layers of second steel pads and multiple layers of second adjustment steel plates which are stacked on the spherical support in sequence, and the two top supports are horizontally aligned with the second adjustment steel plates. All jacks are centrally controlled by the pump station; Monitoring systems, including: A plurality of first stress-strain sensors, used for detecting the settlement and displacement of the load-bearing support; A plurality of second stress-strain sensors, used for detecting stress changes of the landing gear; A plurality of third stress and strain sensors, used to detect stress changes at monitoring points of the beam section; Characterized in that the beam dropping method comprises the following steps: Step 1: Set up the load-bearing support for the bridge piers at the river crossing position, and build at least four sets of temporary support units evenly arranged along the axis of each pier column. Step 2: Arrange the system conversion mechanism, alternately arrange the first steel pads on the double-piece steel base according to the designed number of layers, and place the first adjustment steel plates of different thicknesses on the first steel pads; arrange the second steel pads on the spherical support, and place the second adjustment steel plates of different thicknesses on the second steel pads; the jack is arranged on the first adjustment steel plate and fixedly connected with the top support, and the top support is temporarily welded and fixed to the bottom plate of the steel-concrete composite beam bridge; Step 3: Stress and strain sensors are respectively installed at the detection points of the load-bearing bracket, the lifting and lowering device and the beam section, and data is collected and transmitted to monitor the verticality of the beam lowering device, and the beam lowering amplitude is adjusted according to the monitoring results; Step 4: After all the welds of the beam body are completed, the beam-dropping load-bearing bracket is pre-loaded. The jacks at each pier are controlled by the pump station controller. Each jack is lifted and supported synchronously to 70% of the maximum lifting force of the jack. The lifting force is applied to the beam body so that the beam body begins to be stressed but does not cause vertical displacement. At this time, the round pipe piles and the first steel pads of the beam-dropping load-bearing bracket gradually begin to bear the vertical force. After the stress-strain sensor shows that the pre-load is stable, the load-bearing bracket is inspected and reinforced; Step 5: By adjusting the thickness of the second adjusting steel plate, there is no gap between the spherical bearing and the beam body, and the beam body load is borne by the load-bearing bracket and the pier column; Step 6: Monitor the stress and strain of the load-bearing bracket and the beam, start the whole bridge lowering process, pull out the first adjustment steel plate under the jack, lower the total elevation to the preset value, control the jack to lift synchronously through the pump station controller until the beam is completely separated from the spherical support, pull out part of the second adjustment steel plate to lower the total elevation, then the jack will release the pressure synchronously, the whole bridge will be lowered, and the load will be transferred from the load-bearing bracket to the spherical support again; Step 7: Repeat the above operation to slowly drop the beam until the second steel pad and the second adjustment steel plate on the side span ball bearing are completely pulled out. After the beam is dropped, remove the beam dropping device.

2. The multi-point synchronous embracing beam dropping method for bridge piers according to claim 1, It is characterized in that The bridge pier is a double-column structure, comprising two columns and a cap beam connected between the tops of the two columns, a pedestal is provided at the bottom of the two columns, and at least four groups of temporary support units are arranged around each pier column.

3. The multi-point synchronous embracing beam dropping method for bridge piers according to claim 2, It is characterized in that The first temporary support unit and the second temporary support unit of the four groups of temporary support units are symmetrically arranged on both sides of the connection end between the pier and the cap beam, and the jacking support is connected between the tops of the first temporary support unit and the second temporary support unit; the third temporary support unit and the fourth temporary support unit are arranged at the other end of the pier symmetrical to the first temporary support unit and the second temporary support unit, and the jacking support is provided between the tops of the third temporary support unit and the fourth temporary support unit.

4. The multi-point synchronous embracing beam dropping method for bridge piers according to claim 3, It is characterized in that The jacking supports are all composed of a plurality of H-shaped steels welded together to form a grating plate, and a first stiffening plate is provided on both sides of the ribs of the H-shaped steel corresponding to the jacks, and two pairs of inverted L-shaped fasteners are provided at the bottom of the jacking supports corresponding to the top plates of each jack, and the two pairs of fasteners are snap-fitted to the edges of both sides of the top plate and fixed by welding, and the top of the jacking supports is respectively welded and fixed to the bottom of the beam body.

5. The multi-point synchronous embracing beam dropping method for bridge piers according to claim 4, It is characterized in that Pile foot embedded parts are respectively provided at the bottom of each steel pipe pile in the abutment of the pier, and the steel pipe piles are welded and fixed to the corresponding pile foot embedded parts; auxiliary pier embedded parts corresponding to each steel pipe pile are provided in the facade of the pier column or the cap beam, and there is a spacing between some steel pipe piles in the third temporary support unit and the fourth temporary support unit located on both sides of the outer end of the pier column and the auxiliary pier embedded parts, and a first reinforcing beam is connected in the spacing, and the first reinforcing beam is an H-shaped steel.

6. The multi-point synchronous embracing beam dropping method for bridge piers according to claim 5, It is characterized in that A cover plate constituting a closed structure is welded to the top of each steel pipe pile, and a double-piece steel base is welded and fixed to the center of the cover plate. The double-piece steel base is assembled from two H-shaped steels, and second stiffening plates are respectively provided on both sides of the ribs of the two H-shaped steels. Pier embedded parts corresponding to each double-piece steel base are respectively provided on the outer facades of the pier column and the cap beam, and the double-piece steel base is welded and fixed to the corresponding pier embedded parts.

7. The multi-point synchronous embracing beam dropping method for a bridge pier according to claim 6, It is characterized in that The first steel pad is composed of multiple H-steels stacked in a well-shaped structure, with the H-steels of each layer arranged alternately vertically and horizontally. There are vertically arranged third stiffening plates on both sides of the ribs of each H-steel, and the second steel pad has the same structure as the first steel pad.

8. The multi-point synchronous embracing beam dropping method for bridge piers according to claim 7, It is characterized in that The multiple layers of first adjustment steel plates have the same area but different thicknesses, the multiple layers of second adjustment steel plates have the same area but different thicknesses, and both the first adjustment steel plate and the second adjustment steel plate are used for fine-tuning the elevation; each of the jacks is placed centrally on the corresponding first adjustment steel plate.

9. According to the multi-point synchronous embracing beam dropping method of the pier as described in claim 8, a plurality of second reinforcing beams are connected between the first temporary support unit and the second temporary support unit located at the lower part of the cap beam, the second reinforcing beams are H-shaped steels, and the plurality of second reinforcing beams include horizontal and oblique connection postures; a fifth temporary support unit composed of a single steel pipe pile is provided between the third temporary support unit and the fourth temporary support unit, and a plurality of fourth reinforcing beams are connected between the single steel pipe pile and the third temporary support unit and the fourth temporary support unit, respectively, and the fourth reinforcing beams are H-shaped steels, and the plurality of fourth reinforcing beams are divided into two types: horizontal and oblique settings, and a third reinforcing beam is connected between the double-piece steel base arranged on the top of the fifth temporary support unit and the bottom of the third temporary support unit and the fourth temporary support unit, and the third reinforcing beam is an H-shaped steel.

10. The multi-point synchronous embracing beam dropping method for a bridge pier according to claim 9, It is characterized in that The specific plan for building the load-bearing support in step one is: pre-embed the pile foot embedded parts when tying the steel bars at the pedestal part, and install the steel pipe piles after the pedestal is poured with concrete and cured; pre-embed the attached pier embedded parts when tying the steel bars of the pier column, and after the concrete pouring of the pier column is completed, carry out the steel pipe pile connecting pipe and the transverse reinforcement connection of the steel pipe piles, and after the pier column is cured, set the first reinforcing crossbeam between the steel pipe piles and the attached pier embedded parts that are partly away from the pier column in the third temporary support unit and the fourth temporary support unit to strengthen the connection between the steel pipe piles and the attached pier embedded parts; trim the upper end of the steel pipe pile to the designed top elevation, and then place the cover plate and the double-piece steel base in sequence.

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