A method for resetting the main beam after a damaged bridge pier

Abstract

The present invention relates to the field of bridge technology and provides a method for resetting a main beam after a pier is damaged. The method comprises obtaining the current vertical displacement of the main beam above the damaged pier and the theoretical position of the main beam before damage, obtaining the theoretical support reaction of the support of the damaged pier before and after damage, lifting the main beam to the theoretical position, removing the support, support pedestal, cap beam, and pier column of the damaged pier, constructing new pier columns and new cap beams, and then obtaining the corrected actual support reaction of the support of the damaged pier before damage. The method then uses the tensile stress threshold of the bridge deck pavement as a control target, continues to lift the main beam, installs new support pedestal stones and new supports, and completes the main beam reset when the actual support reaction of the main beam after the beam is dropped is within the required range. The present application creatively proposes a scheme for resetting the main beam of a damaged pier, which can reset the main beam to its original position before damage, ensures reasonable structural stress, improves construction quality, does not cause cracking of the bridge deck pavement, and effectively improves construction efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of bridges, and in particular to a method for resetting a main beam after a bridge pier is damaged. Background Art

[0002] For elevated high-pier bridges built in high-slope areas or with traffic passing below, the high slopes are prone to landslides due to rain erosion or artificial soil piles, causing the lower structure piers to be damaged and bent. Bridges with traffic passing below are also prone to damage and bending of the lower structure piers when the piers are hit by large vehicles, and in severe cases, even cause the bridge to collapse.

[0003] When repairing or replacing damaged or bent piers, the superstructure's main beam must be lifted back into place before being re-jacked up again. After replacing the damaged pier, the main beam must be lowered back into place, a complex process. Currently, research is underway on jacking up the entire bridge and replacing all bearings on undamaged bridges. This can be accomplished by uniformly jacking up the bearings through displacement monitoring, then lowering them back into place.

[0004] However, regarding the damage to the bridge pier, the original position of the main beam before the damage is unclear. Moreover, if the main beam support at the damaged position is only partially lifted up to replace the damaged pier after the damage, how can the main beam ensure that the bridge deck pavement is not stretched and cracked during the lifting process, and how can the main beam be restored to its position before the damage after the beam is dropped so that the main beam structure and support are reasonably stressed? There is currently no relevant discussion.

[0005] In view of this, it is necessary to propose a method for resetting the main beam after the pier is damaged to solve or at least alleviate the above defects. Summary of the Invention

[0006] The main purpose of the present invention is to provide a method for resetting the main beam after a bridge pier is damaged, so as to solve the technical problem in the prior art of lacking an effective solution for resetting the main beam after a bridge pier is damaged.

[0007] To achieve the above object, the present invention provides a method for resetting a main beam after a pier is damaged, comprising the following steps:

[0008] S1, obtain the current vertical displacement of the main beam above the damaged pier and the theoretical position of the main beam before damage;

[0009] S2, establishing a finite element calculation model of the original bridge structure before damage, obtaining a theoretical support reaction force F0 of the damaged pier support before damage based on the finite element calculation model, and then obtaining a theoretical support reaction force F1 of the damaged pier support after damage based on the current vertical displacement and the finite element calculation model;

[0010] S3: Use a jacking device to lift the main beam to the theoretical position, determine the lifting stiffness of the main beam, remove the supports, support pads, cap beams, and pier columns of the damaged piers, and construct new pier columns and cap beams according to the original design requirements;

[0011] S4, modifying the finite element calculation model based on the lifting stiffness, obtaining the modified actual support reaction force F2 of the damaged pier before the damage, and then using the bridge deck pavement tensile stress threshold as a control target to obtain the maximum lifting amount and lifting force threshold of the main beam when the damaged pier is lifted;

[0012] S5, continue to jack up the main beam using the jacking device, and install new support pads and new supports;

[0013] S6, unload the jacking device to make the main beam fall on the new support, and calculate the actual support reaction force F3 of the main beam after the beam falls. When the first deviation value between the actual support reaction force F3 and the actual support reaction force F2 is within a preset range, the main beam is reset.

[0014] Preferably, the step S1 specifically includes the following steps:

[0015] S11, using a three-dimensional laser scanner to scan the spatial position of the damaged bridge to obtain current spatial position information of the bridge, and obtaining the coordinates of a second point (x2, y2, z2) of the bottom surface of the main beam above the damaged pier, as well as the coordinates of a first point (x1, y1, z1) and a third point (x3, y3, z3) of the bottom surface of the main beam at a pier or abutment adjacent to the damaged pier from the current spatial position information of the bridge; wherein the x-coordinate direction is the bridge axis direction, the y-coordinate direction is the direction perpendicular to the x-coordinate direction in the horizontal plane, and the z-coordinate direction is the vertical direction;

[0016] S12, using formula z i = (x2-x1) / (x3-x1)×(z3-z1) to calculate the vertical theoretical position z of the bottom surface of the main beam above the damaged pier i , and the bottom vertical theoretical position z i As the theoretical position;

[0017] S13, using the formula α=z i -z2 obtains the current vertical displacement α of the main beam above the damaged pier.

[0018] Preferably, the lifting device includes a jack and a pressure sensor located on the top of the jack, and step S3 specifically includes the following steps:

[0019] S31, constructing temporary supports on both sides of the damaged pier, and sequentially constructing a jack and a pressure sensor on top of each temporary support; wherein the jack and pressure sensor are located between the temporary support and the main beam;

[0020] S32: Before the main girder is lifted, a vertical displacement meter is installed to obtain displacement values ​​during lifting and lowering of the main girder. The upper end of the vertical displacement meter is connected to the bottom of the main girder, and the lower end is connected to the top of the cap beam of the damaged pier. At least one vertical displacement meter is arranged on each side of the damaged pier in the transverse direction of the bridge.

[0021] S33, lifting the main beam to the theoretical position evenly in stages, recording the lifting force F4 when the main beam just leaves the damaged pier, and recording the lifting force increment ΔF and displacement increment Δh at each stage of lifting force;

[0022] S34, using the formula k=ΔF / Δh to calculate the jacking stiffness of each stage, and taking the average of the jacking stiffness of all stages as the jacking stiffness of the main beam;

[0023] S35, recording the final displacement of the vertical displacement meter when the main beam is jacked up to the theoretical position, and removing the vertical displacement meter;

[0024] S36, dismantle the pier columns, cap beams, support pads and supports of the damaged piers, construct new pier columns and cap beams according to the original design requirements, and then reinstall the vertical displacement meter.

[0025] Preferably, the step S4 specifically includes the following steps:

[0026] S41, obtaining an actual elastic modulus E0 of the bridge according to the jacking stiffness;

[0027] S42, calculating the weight correction coefficient of the main beam based on the theoretical support reaction force F1 and the jacking force F4, and then obtaining the corrected main beam bulk density γ based on the weight correction coefficient;

[0028] S43, substituting the actual elastic modulus E0 and the main beam bulk density γ into the finite element calculation model to obtain a revised finite element calculation model, and then obtaining the actual support reaction force F2 of the damaged pier support before damage based on the revised finite element calculation model;

[0029] S44, taking the bridge deck pavement tensile stress threshold as the control target, obtain the maximum lifting amount H of the main beam when the damaged pier is lifted and the lifting force threshold F5.

[0030] Preferably, step S5 specifically includes the following steps:

[0031] S51, using either the maximum lifting amount H or the lifting force threshold F5 as a limit, continuing to lift the main beam, and recording the lifting force F6 after the main beam is lifted to the limit;

[0032] S52, calculating the compression deformation h1 of the support of the damaged pier and the compression deformation h2 of the column of the damaged pier under the action of the actual support reaction force F2;

[0033] S53, calculate the distance h0 between the top surface of the support of the damaged pier and the bottom surface of the main beam during construction using the formula h0 = (F6-F2) / k-h1-h2;

[0034] S54, obtaining the actual distance h3 between the top surface of the new support and the bottom surface of the main beam;

[0035] S55, calculate the new support reaction F7 of the main beam after the beam is dropped, and calculate the second deviation value between the new support reaction F7 and the actual support reaction F2; when the second deviation value is controlled within ±5%, it is judged to be qualified; when the second deviation value exceeds ±5%, correct the elevation of the new support pad stone and then control the main beam to drop.

[0036] Preferably, the step S6 specifically includes the following steps:

[0037] S61, unload the jack and drop the main beam onto the new support;

[0038] S62, obtaining the displacement value h4 of the main beam after the actual beam drop;

[0039] S63, use the formula F3=F6-kh4 to calculate the actual support reaction F3 after the beam is dropped, and calculate the first deviation value between the actual support reaction F3 and the actual support reaction F2; when the first deviation value is controlled within the preset range, it is judged to be qualified; when the first deviation value exceeds the preset range, correct the elevation of the new support pad stone and then control the main beam to drop the beam.

[0040] Preferably, the step S55 of calculating the new support reaction force F7 of the main beam after the beam is dropped specifically includes the steps of: using the formula F7=F6-k(h1+h2+h3) to calculate the new support reaction force F7 of the main beam after the beam is dropped.

[0041] Preferably, both the damaged pier support and the new support are rubber supports, and the compression deformation h1 in step S52 is obtained by the following steps:

[0042] Using the formula h1=(F2×h) / (A 座 ×E 橡胶 ) / a to obtain the compression deformation h1 of the damaged pier under the actual support reaction force F2; where h is the total thickness of the support, A 座 is the effective bearing area of ​​the support, E 橡胶is the elastic modulus of the support material, and a is the number of supports.

[0043] Preferably, the compression deformation h2 in step S52 is obtained by the following steps:

[0044] Using the formula h2=(F2×L 柱 ) / (A 柱 ×E 墩柱 ) / 2 to calculate the compression deformation h2 of the damaged pier column under the actual support reaction force F2; where L 柱 is the free length of the damaged pier, A 柱 is the cross-sectional area of ​​the damaged pier, E 墩柱 is the elastic modulus of the pier material.

[0045] Preferably, the first deviation value is set to ±10%.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention provides a method for resetting the main beam after a bridge pier is damaged. The method comprises the following steps: obtaining the current vertical displacement of the main beam above the damaged pier and the theoretical position of the main beam before the damage, obtaining the theoretical support reaction force of the support of the damaged pier before and after the damage, lifting the main beam to the theoretical position, removing the support, support pedestal stone, cap beam, and pier column of the damaged pier, constructing new pier columns and new cap beam, and then obtaining the actual support reaction force of the support of the damaged pier before the damage after correction. Then, taking the tensile stress threshold of the bridge deck pavement as the control target, continuing to lift the main beam, installing the new support pedestal stone and the new support, and completing the main beam resetting when the actual support reaction force of the main beam after the beam is dropped is calculated to be within the required range.

[0048] This application creatively proposes a scheme for resetting the main beam of damaged bridge piers, which can reset the main beam to its original position before damage, ensure reasonable stress on the structure, improve construction quality, and will not cause cracks in the bridge deck pavement, effectively improving construction efficiency; this application uses finite element calculation results, and combines on-site measurement results to calculate the actual support reaction force after controlling the beam drop, ensuring that the structure and support stress are close to the original design and construction status, the structure is reasonably stressed, the safety risk of later operation is small, and the later maintenance costs can be saved; this application does not jack up the entire bridge, but uses local jacking to reset the main beam. Compared with the original jacking construction, it can reduce equipment and personnel investment, make the control process simpler, and improve construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0050] Figure 1 Schematic diagram of a process in one embodiment of the present invention;

[0051] Figure 2 is a schematic structural diagram of a damaged bridge pier in one embodiment of the present invention;

[0052] Figure 3 A schematic diagram of scanning using a three-dimensional laser scanner in one embodiment of the present invention;

[0053] Figure 4 Schematic diagram of the structure of the main beam before and after damage in one embodiment of the present invention;

[0054] Figure 5 for Figure 4 A is an enlarged schematic diagram;

[0055] Figure 6 Schematic diagram of the installation of a vertical displacement meter in one embodiment of the present invention;

[0056] Figure 7 Schematic diagram of the longitudinal bridge arrangement of a temporary support and a jacking device in one embodiment of the present invention;

[0057] Figure 8 Schematic diagram of the transverse bridge arrangement of temporary supports and jacking devices in one embodiment of the present invention.

[0058] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments.

[0059] Description of Figure Numbers:

[0060] 10. Damaged bridge pier; 110. Pier column of the damaged bridge pier; 120. Cap beam of the damaged bridge pier; 20. Abutment; 30. Main beam; 310. Top surface of the main beam before damage; 320. Bottom surface of the main beam before damage; 330. Top surface of the main beam after damage; 340. Bottom surface of the main beam after damage; 350. First point; 360. Second point; 370. Third point; 40. Lifting device; 410. Jack; 420. Pressure sensor; 50. Temporary support; 60. Three-dimensional laser scanner; 70. Vertical displacement meter. DETAILED DESCRIPTION

[0061] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0062] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0063] In the present invention, the descriptions of "first," "second," etc. are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions of the various embodiments may be combined with each other, but this must be based on the fact that they can be implemented by a person of ordinary skill in the art. If the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0064] Please see the attached Figures 1 to 8 In one embodiment of the present invention, a method for resetting a main beam after a pier is damaged comprises the following steps:

[0065] S1, obtaining the current vertical displacement of the main beam 30 above the damaged pier 10 and the theoretical position of the main beam 30 before the damage; Figure 4 As shown, Figure 4 3. The schematic diagram of the structure of the main beam before and after damage includes the top surface 310 of the main beam before damage, the bottom surface 320 of the main beam before damage, the top surface 330 of the main beam after damage, and the bottom surface 340 of the main beam after damage. The vertical difference between the bottom surface 320 of the main beam before damage and the bottom surface 340 of the main beam after damage can reflect the amount of sinking of the main beam 30.

[0066] S2, establishing a finite element calculation model of the original bridge structure before damage, obtaining a theoretical support reaction force F0 of a support (not shown) of the damaged pier before damage based on the finite element calculation model, and then obtaining a theoretical support reaction force F1 of the support of the damaged pier after damage based on the current vertical displacement and the finite element calculation model;

[0067] Specifically, the original structural design drawings, material parameters, and structural loads of the bridge to be constructed can be obtained as basic data for finite element calculations. Relying on this basic data and the bridge construction plan and process, a simulation calculation model of the bridge structure can be established. This part is conventional existing technology and will not be described in detail here. After obtaining the finite element calculation model, the theoretical position of the damaged pier 10 before damage and the theoretical support reaction force F0 of the damaged pier's support before damage can be directly obtained. By simulating the actual displacement of the pier (i.e., the current vertical displacement) through the finite element calculation model, the theoretical support reaction force F1 of the damaged pier 10 can be directly extracted from the finite element calculation model. The extraction process is conventional technology and will not be described in detail here.

[0068] Based on the displacement of the main beam 30 and the pier obtained by the three-dimensional scanning in step S1, the stress state of the bridge structure under the existing situation is analyzed in the finite element calculation model, and the structural stress and bearing capacity of the structure without considering the combination of moving loads and variable loads such as wind and temperature are determined, and the theoretical support reaction F1 at this time is obtained; wherein, if the calculated values ​​of the structural stress and bearing capacity are less than the standard values, measures should be taken immediately to strengthen the structure to ensure the safety of the structure during the construction process; if the calculated values ​​are greater than the standard values, measures should be taken to ensure that the existing structural state does not deteriorate further.

[0069] S3, using the jacking device 40 to jack up the main beam 30 to the theoretical position, and determine the jacking stiffness of the main beam 30, remove the supports, support pads, cap beam 120, and pier columns 110 of the damaged bridge piers, and construct new pier columns (not shown) and new cap beams (not shown) according to the original design requirements;

[0070] S4, based on the jacking stiffness, the finite element calculation model is modified to obtain the actual support reaction force F2 of the damaged pier before the damage. Then, using the bridge deck pavement tensile stress threshold as a control target, the maximum jacking amount and jacking force threshold of the main beam 30 when the damaged pier 10 is jacked are obtained;

[0071] S5, use the jacking device 40 to continue jacking up the main beam 30, and install the new support pedestal and the new support; it is worth noting that in order to ensure the installation of the new support pedestal and the new support, the main beam 30 needs to be over-jacked after being jacked back to the theoretical position to ensure that there is a certain space for the construction.

[0072] S6, unload the jacking device 40 to allow the main beam 30 to fall on the new support, and calculate the actual support reaction force F3 of the main beam 30 after the beam is dropped. When the first deviation value between the actual support reaction force F3 and the actual support reaction force F2 is within a preset range, the main beam 30 is reset.

[0073] In the present application, the present application creatively proposes a scheme for resetting the main beam 30 of the damaged pier 10, which can reset the main beam 30 to its original position before damage, ensure reasonable structural stress, improve construction quality, and will not cause cracks in the bridge deck pavement, effectively improving construction efficiency; the present application adopts finite element calculation results, and combines on-site measurement results to calculate the actual support reaction force after controlling the beam drop, ensuring that the structure and support stress are close to the original design and construction status, the structural stress is reasonable, the safety risk of later operation is small, and the later maintenance costs can be saved; the present application does not jack up the entire bridge, but uses local jacking to reset the main beam 30. Compared with the original jacking construction, it can reduce equipment and personnel investment, make the control process simpler, and improve construction efficiency.

[0074] As a preferred embodiment, step S1 specifically includes the following steps:

[0075] S11, using a three-dimensional laser scanner 60 to scan the spatial position of the damaged bridge to obtain current spatial position information of the bridge, and obtaining the second point coordinates (x2, y2, z2) of the bottom surface of the main beam 30 above the damaged pier 10, and the first point coordinates (x1, y1, z1) and the third point coordinates (x3, y3, z3) of the bottom surface of the main beam 30 at the position of the pier or abutment 20 adjacent to the damaged pier 10 from the current spatial position information of the bridge; wherein the x-coordinate direction is the bridge axis direction, the y-coordinate direction is the direction perpendicular to the x-coordinate direction in the horizontal plane, and the z-coordinate direction is the vertical direction;

[0076] S12, using formula z i = (x2-x1) / (x3-x1)×(z3-z1) to calculate the vertical theoretical position z of the bottom surface of the main beam 30 above the damaged pier 10 i , and the bottom vertical theoretical position z i As the theoretical position;

[0077] S13, using the formula α=z i -z2 obtains the current vertical displacement α of the main beam 30 above the damaged pier 10.

[0078] like Figure 3 and Figure 4 As shown, this embodiment uses a three-dimensional laser scanner 60 to scan the spatial position of the damaged bridge to obtain the current spatial position information of the bridge. Preferably, the scanning distance of the three-dimensional laser scanner should reach more than 300m, and the corresponding measurement accuracy should be controlled within 3mm. After scanning, a three-dimensional stereoscopic figure is formed, and the spatial coordinate value of any point on the exposed part of the structure can be identified after software processing and analysis.

[0079] To better obtain the theoretical vertical position of the bottom surface, this embodiment selects the second point 360, the first point 350, and the third point 370 for coordinate calculation to obtain the theoretical vertical position of the bottom surface. Preferably, the second point 360 is the point where the center of the top surface of the damaged pier 10 is projected upward onto the bottom surface of the main beam 30. The first point 350 is the intersection of the center of the support at the adjacent abutment 20 and the bottom surface of the main beam 30. For a bridge with two rows of supports on a single pier, the intersection is the center between the two rows of supports and the bottom surface of the main beam 30. The third point 370 is the intersection of the center of the support of the adjacent pier and the bottom surface of the main beam 30.

[0080] Preferably, the vertical displacement of the bottom surface of the main beam 30 along the x-axis direction (bridge axis) changes linearly, that is, the line between the first point 350 and the third point 370 does not undergo significant settlement. Based on the coordinates of the adjacent undamaged points, the theoretical vertical coordinate z of the point above the damaged pier 10 can be obtained by linear interpolation calculation. i , and the bottom vertical theoretical position z i As the theoretical position; this embodiment can quickly and accurately obtain the settlement (vertical displacement) and theoretical position of the damaged pier 10.

[0081] As a preferred embodiment, Figures 6 to 8 As shown, the lifting device 40 includes a jack 410 and a pressure sensor 420 located on the top of the jack 410. Step S3 specifically includes the following steps:

[0082] S31, constructing temporary supports 50 on both sides of the damaged pier 10, and sequentially constructing a jack 410 and a pressure sensor 420 on top of each temporary support 50; wherein the jack 410 and the pressure sensor 420 are located between the temporary support 50 and the main beam 30;

[0083] Preferably, jacks 410 and pressure sensors 420 are installed between the main beam 30 and the temporary supports 50. Jacks 410 and pressure sensors should be installed vertically to ensure they bear axial force. Temporary supports 50 are symmetrically arranged on both sides of the damaged pier 10, serving as temporary supports for lifting the main beam 30. Jacks 410 are used to lift the main beam 30.

[0084] S32: Before the main beam 30 is lifted, a vertical displacement meter 70 is installed to obtain displacement values ​​of the main beam 30 during lifting and lowering. The upper end of the vertical displacement meter 70 is connected to the bottom of the main beam 30, and the lower end is connected to the top of the cap beam 120 of the damaged pier. At least one vertical displacement meter 70 is arranged on each side of the damaged pier 10 in the transverse direction of the bridge.

[0085] S33, lifting the main beam 30 to the theoretical position in a graded and uniform manner, recording the lifting force F4 when the main beam 30 just leaves the damaged pier 10, and recording the lifting force increment ΔF and displacement increment Δh at each level of lifting force;

[0086] As a preferred example, initial jacking targets the theoretical support reaction F1, while staged jacking primarily controls the lifting force. After the main beam 30 is free of the damaged pier 10, staged jacking primarily controls the lifting displacement, supplemented by the lifting force. To ensure safety, the staged jacking is performed in a progressively decreasing manner, starting with higher and then decreasing levels. When controlling the lifting force, jacking is performed in at least three stages (50%, 80%, and 100% cumulative force). When controlling the lifting displacement, when the theoretical displacement is within 5 cm, at least four stages are performed (40%, 70%, 90%, and 100% cumulative displacement). When the theoretical displacement exceeds 5 cm, at least five stages are performed (30%, 55%, 80%, 90%, and 100% cumulative displacement).

[0087] S34, using the formula k=ΔF / Δh to calculate the jacking stiffness of each stage, and taking the average of the jacking stiffness of all stages as the jacking stiffness of the main beam 30;

[0088] S35, recording the final displacement of the vertical displacement meter 70 when the main beam 30 is jacked up to the theoretical position, and removing the vertical displacement meter 70;

[0089] S36, dismantle the pier column 110, cap beam 120, bearing pad stone, and bearing of the damaged pier, construct new pier column and cap beam according to the original design requirements, and then reinstall the vertical displacement meter 70.

[0090] Specifically, this embodiment sets up temporary supports 50 on both sides of the damaged pier 10 to form a stable support structure. Temporary steel pipe piers can be installed directly and connected via I-beams. Jacks 410 and pressure sensors 420 are installed on top of the supports to monitor the lifting force in real time and ensure that the lifting force is evenly transmitted to the bottom of the main beam 30. Vertical displacement meters 70 are installed on both sides of the damaged pier 10, with one end fixed to the bottom of the main beam 30 and the other end fixed to the top of the pier cap beam. The vertical displacement meters 70 are used to measure the vertical displacement of the main beam 30 during the lifting process. The average value of the vertical displacement meters 70 on both sides is taken for each state. The lifting stiffness of each level is calculated and the average value is used to assess the overall stiffness of the main beam 30 to prevent local overload or structural damage. After lifting to the theoretical position, the vertical displacement meters 70 are used to verify the consistency of the actual displacement with the theoretical value to ensure lifting accuracy. The damaged pier 10 is dismantled, and a new pier is rebuilt according to the original design requirements. The displacement meters are then reinstalled to monitor the reset process. Ensure that the elevations of the new piers and cap beams are consistent with the previous ones.

[0091] It is worth noting that after the main beam 30 is lifted to the theoretical position, the final displacement of the vertical displacement meter 70 is recorded. After the construction of the new pier and the new cap beam is completed, the vertical displacement meter 70 is reinstalled. The installation position is preferably corresponding to the previous installation position. When the main beam 30 is subsequently super-lifted, the final displacement recorded previously plus the displacement monitored after reinstallation is the total displacement of the main beam 30.

[0092] As a preferred embodiment, step S4 specifically includes the following steps:

[0093] S41, obtaining an actual elastic modulus E0 of the bridge according to the jacking stiffness;

[0094] It should be noted that for multi-span continuous beams, the theoretical jacking stiffness coefficient of the middle support is k=24EI / L 3 At this point, F = kδ, where F is the lifting force, δ is the displacement of main beam 30 at the lifting point, E is the elastic modulus of the main beam 30 material, I is the moment of inertia of the main beam 30 cross section, and L is the span of main beam 30. The lifting stiffness and theoretical lifting stiffness coefficient calculated in step S3 above can be used to infer the actual elastic modulus E0 of the bridge, avoiding the traditional structurally destructive core sampling method and improving efficiency. This process is a mature existing technology and will not be detailed here.

[0095] S42, calculate the weight correction coefficient of the main beam 30 based on the theoretical support reaction force F1 and the jacking force F4, and then obtain the corrected bulk density γ of the main beam 30 based on the weight correction coefficient. Specifically, the weight correction coefficient μ of the main beam 30 can be calculated using the formula μ = F2 / F1. The corrected bulk density of the main beam 30 is γ = μ × γ 理 , γ 理 The theoretical density of the main beam 30.

[0096] S43, substituting the actual elastic modulus E0 and the bulk density γ of the main beam 30 into the finite element calculation model to obtain a revised finite element calculation model, and then obtaining the actual support reaction force F2 of the damaged pier support before damage based on the revised finite element calculation model;

[0097] S44 , taking the bridge deck pavement tensile stress threshold as a control target, obtain the maximum lifting amount H and the lifting force threshold F5 of the main beam 30 when the damaged pier 10 is lifted.

[0098] As a preferred embodiment, step S5 specifically includes the following steps:

[0099] S51, using either the maximum lifting amount H or the lifting force threshold F5 as a limit, continuing to lift the main beam 30, and recording the lifting force F6 after the main beam 30 is lifted to the limit;

[0100] S52, calculating the compression deformation h1 of the support of the damaged pier and the compression deformation h2 of the pier column 110 of the damaged pier under the action of the actual support reaction force F2;

[0101] As a preferred embodiment, the damaged pier support and the new support are both rubber support. The compression deformation h1 in step S52 is obtained by the following steps:

[0102] Using the formula h1=(F2×h) / (A 座 ×E 橡胶 ) / a to obtain the compression deformation h1 of the damaged pier under the actual support reaction force F2; where h is the total thickness of the support, A 座 is the effective bearing area of ​​the support, E 橡胶 is the elastic modulus of the support material, and a is the number of supports.

[0103] If both the damaged pier support and the new support adopt laminated rubber bearings, the elastic modulus E of the laminated rubber bearings 修 The shape factor S (related to the thickness and diameter of the single layer of rubber) needs to be considered, and the formula is corrected to E 修 =E 橡胶 ×(1+2nS 2 ), where n is the rubber material constant and S = diameter / (4×single-layer rubber thickness).

[0104] As a preferred embodiment, the compression deformation h2 in step S52 is obtained by the following steps: using the formula h2=(F2×L 柱 ) / (A 柱 ×E 墩柱 ) / 2 to calculate the compression deformation h2 of the damaged pier column 110 under the actual support reaction force F2; where L 柱 is the free length of the damaged pier column 110, A 柱 is the cross-sectional area of ​​the damaged pier column 110, E 墩柱 is the elastic modulus of the pier material.

[0105] S53. Calculate the distance h0 between the top surface of the support of the damaged pier and the bottom surface of the main beam 30 during construction using the formula h0 = (F6 - F2) / k - h1 - h2. This value can be used as a reference for those skilled in the art.

[0106] S54, obtain the actual distance h3 between the top surface of the new support and the bottom surface of the main beam 30; as described above, at this time, the new displacement is obtained by reinstalling the vertical displacement meter 70, and the actual distance h3 is the new displacement plus the final displacement previously recorded by the vertical displacement meter 70.

[0107] S55, calculate the new support reaction F7 of the main beam 30 after the beam is dropped, and calculate the second deviation value between the new support reaction F7 and the actual support reaction F2; when the second deviation value is controlled within ±5%, it is judged to be qualified; when the second deviation value exceeds ±5%, correct the elevation of the new support pad stone and then control the main beam 30 to drop the beam.

[0108] Furthermore, the step S55 of calculating the new support reaction force F7 of the main beam 30 after the beam is dropped specifically includes the steps of: using the formula F7=F6-k(h1+h2+h3) to calculate the new support reaction force F7 of the main beam 30 after the beam is dropped.

[0109] This embodiment adopts dual-threshold protection to avoid over-limit lifting and improve safety.

[0110] Furthermore, the step S6 specifically includes the following steps:

[0111] S61, unloading the jack 410, and dropping the main beam 30 onto the new support;

[0112] S62, obtain the displacement value h4 of the main beam 30 after the actual beam is dropped; the displacement value h4 can be directly obtained by the vertical displacement meter 70 to obtain the new displacement, and then the new displacement is added to the final displacement recorded previously to obtain the displacement value h4 of the main beam 30 from the limit position to the beam drop position. From another perspective, the displacement value h4 includes the net distance from the main beam 30 to the top surface of the new support, the compression deformation of the new support and the compression deformation of the new pier.

[0113] S63, using the formula F3 = F6 - kh4 to calculate the actual support reaction force F3 after the beam is dropped, and also calculating a first deviation between the actual support reaction force F3 and the actual support reaction force F2. If the first deviation is within a preset range, the result is considered acceptable. If the first deviation exceeds the preset range, the elevation of the new support shim is corrected before controlling the main beam 30 to drop. Preferably, the first deviation is set to ±10%.

[0114] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for resetting a main beam after a bridge pier is damaged, characterized in that: The following steps are involved: S1, obtain the current vertical displacement of the main beam above the damaged pier and the theoretical position of the main beam before damage; S2, establishing a finite element calculation model of the original bridge structure before damage, obtaining a theoretical support reaction force F0 of the damaged pier support before damage based on the finite element calculation model, and then obtaining a theoretical support reaction force F1 of the damaged pier support after damage based on the current vertical displacement and the finite element calculation model; S3: Use a jacking device to lift the main beam to the theoretical position, determine the lifting stiffness of the main beam, remove the supports, support pads, cap beams, and pier columns of the damaged piers, and construct new pier columns and cap beams according to the original design requirements; S4, modifying the finite element calculation model based on the lifting stiffness, obtaining the modified actual support reaction force F2 of the damaged pier before the damage, and then using the bridge deck pavement tensile stress threshold as a control target to obtain the maximum lifting amount and lifting force threshold of the main beam when the damaged pier is lifted; S5, continue to jack up the main beam using the jacking device, and install new support pads and new supports; S6, unload the jacking device to make the main beam fall on the new support, and calculate the actual support reaction force F3 of the main beam after the beam falls. When the first deviation value between the actual support reaction force F3 and the actual support reaction force F2 is within a preset range, the main beam is reset.

2. The main beam restoration method after a damaged pier according to claim 1 is characterized in that: The step S1 specifically includes the following steps: S11, using a three-dimensional laser scanner to scan the spatial position of the damaged bridge to obtain current spatial position information of the bridge, and obtaining the coordinates of a second point (x2, y2, z2) of the bottom surface of the main beam above the damaged pier, as well as the coordinates of a first point (x1, y1, z1) and a third point (x3, y3, z3) of the bottom surface of the main beam at a pier or abutment adjacent to the damaged pier from the current spatial position information of the bridge; wherein the x-coordinate direction is the bridge axis direction, the y-coordinate direction is the direction perpendicular to the x-coordinate direction in the horizontal plane, and the z-coordinate direction is the vertical direction; S12, using formula z i = (x2-x1) / (x3-x1)×(z3-z1)+z1 Calculate the vertical theoretical position z of the bottom surface of the main beam above the damaged pier i , and the bottom vertical theoretical position z i As the theoretical position; S13, using the formula α=z i -z2 obtains the current vertical displacement α of the main beam above the damaged pier.

3. The main beam restoration method after a damaged pier according to claim 1 is characterized in that: The lifting device includes a jack and a pressure sensor located on the top of the jack, and step S3 specifically includes the following steps: S31, constructing temporary supports on both sides of the damaged pier, and sequentially constructing a jack and a pressure sensor on top of each temporary support; wherein the jack and pressure sensor are located between the temporary support and the main beam; S32: Before the main girder is lifted, a vertical displacement meter is installed to obtain displacement values ​​during lifting and lowering of the main girder. The upper end of the vertical displacement meter is connected to the bottom of the main girder, and the lower end is connected to the top of the cap beam of the damaged pier. At least one vertical displacement meter is arranged on each side of the damaged pier in the transverse direction of the bridge. S33, lifting the main beam to the theoretical position evenly in stages, recording the lifting force F4 when the main beam just leaves the damaged pier, and recording the lifting force increment ΔF and displacement increment Δh at each stage of lifting force; S34, using the formula k=ΔF / Δh to calculate the jacking stiffness of each stage, and taking the average of the jacking stiffness of all stages as the jacking stiffness of the main beam; S35, recording the final displacement of the vertical displacement meter when the main beam is jacked up to the theoretical position, and removing the vertical displacement meter; S36, dismantle the pier columns, cap beams, support pads and supports of the damaged piers, construct new pier columns and cap beams according to the original design requirements, and then reinstall the vertical displacement meter.

4. The method for resetting the main beam after a damaged pier according to claim 3 is characterized in that: The step S4 specifically includes the following steps: S41, obtaining an actual elastic modulus E0 of the bridge according to the jacking stiffness; S42, calculating the weight correction coefficient of the main beam based on the theoretical support reaction force F1 and the jacking force F4, and then obtaining the corrected main beam bulk density γ based on the weight correction coefficient; S43, substituting the actual elastic modulus E0 and the main beam bulk density γ into the finite element calculation model to obtain a revised finite element calculation model, and then obtaining the actual support reaction force F2 of the damaged pier support before damage based on the revised finite element calculation model; S44, taking the bridge deck pavement tensile stress threshold as the control target, obtain the maximum lifting amount H of the main beam when the damaged pier is lifted and the lifting force threshold F5.

5. The method for resetting the main beam after a damaged pier according to claim 4 is characterized in that: The step S5 specifically includes the following steps: S51, using either the maximum lifting amount H or the lifting force threshold F5 as a limit, continuing to lift the main beam, and recording the lifting force F6 after the main beam is lifted to the limit; S52, calculating the compression deformation h1 of the support of the damaged pier and the compression deformation h2 of the column of the damaged pier under the action of the actual support reaction force F2; S53, calculate the distance h0 between the top surface of the support of the damaged pier and the bottom surface of the main beam during construction using the formula h0 = (F6-F2) / k-h1-h2; S54, obtaining the actual distance h3 between the top surface of the new support and the bottom surface of the main beam; S55, calculate the new support reaction F7 of the main beam after the beam is dropped, and calculate the second deviation value between the new support reaction F7 and the actual support reaction F2; when the second deviation value is controlled within ±5%, it is judged to be qualified; when the second deviation value exceeds ±5%, correct the elevation of the new support pad stone and then control the main beam to drop.

6. The method for resetting the main beam after a damaged pier according to claim 3 is characterized in that: The step S6 specifically includes the following steps: S61, unload the jack and drop the main beam onto the new support; S62, obtaining the displacement value h4 of the main beam after the actual beam drop; S63, use the formula F3=F6-kh4 to calculate the actual support reaction F3 after the beam is dropped, and calculate the first deviation value between the actual support reaction F3 and the actual support reaction F2; when the first deviation value is controlled within the preset range, it is judged to be qualified; when the first deviation value exceeds the preset range, correct the elevation of the new support pad stone and then control the main beam to drop the beam.

7. The method for resetting the main beam after a damaged pier according to claim 5 is characterized in that: The step S55 of calculating the new support reaction force F7 of the main beam after the beam is dropped specifically includes the following steps: using the formula F7=F6-k(h1+h2+h3) to calculate the new support reaction force F7 of the main beam after the beam is dropped.

8. The method for resetting the main beam after a damaged pier according to claim 5 is characterized in that: The damaged pier support and the new support are both rubber supports. The compression deformation h1 in step S52 is obtained by the following steps: Using the formula h1=(F2×h) / (A 座 ×E 橡胶 ) / a to obtain the compression deformation h1 of the damaged pier under the actual support reaction force F2; where h is the total thickness of the support, A 座 is the effective bearing area of ​​the support, E 橡胶 is the elastic modulus of the support material, and a is the number of supports.

9. The method for resetting the main beam after a damaged pier according to claim 5, characterized in that: The compression deformation h2 in step S52 is specifically obtained by the following steps: Using the formula h2=(F2×L 柱 ) / (A 柱 ×E 墩柱 ) / 2 to calculate the compression deformation h2 of the damaged pier column under the actual support reaction force F2; where L 柱 is the free length of the damaged pier, A 柱 is the cross-sectional area of ​​the damaged pier, E 墩柱 is the elastic modulus of the pier material.

10. The method for resetting the main beam after a damaged pier according to any one of claims 1 to 9, characterized in that: The first deviation value is set to ±10%.

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