A differential pushing step-by-step jack for a curved bridge and a pushing method

Abstract

The application discloses a curved bridge differential pushing step-by-step jack, which comprises a first step-by-step jack and a second step-by-step jack, the first step-by-step jack is arranged on the inner side of the curved bridge, and the first step-by-step jack comprises a base, a longitudinal sliding box, a transverse sliding box, a vertical jack and a plate rubber support; the longitudinal sliding box is placed on a sliding channel of the base, the transverse sliding box is placed in a space of the longitudinal sliding box and can only move in the transverse direction, the vertical jack is placed in a space of the transverse sliding box and can rotate freely, and the plate rubber support is placed on the vertical jack and is located below the pushing bridge; and the second step-by-step jack is arranged on the outer side of the curved bridge. The curved bridge differential pushing step-by-step jack can adapt to the rotation of a beam body, transverse displacement and longitudinal differential displacement in the differential pushing process, and in cooperation with the pushing method, the oil pump control system of the common step-by-step jack can realize the differential pushing of the curved bridge.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, and in particular to a differential speed jacking walking jack and jacking method for curved bridges. Background Technology

[0002] The incremental launching method is widely used in the construction of continuous beam bridges with uniform cross-sections, including single-point launching and multi-point launching. In recent years, the multi-point launching method using walking jacks has been widely adopted. This method does not affect traffic or navigation under the bridge and can be well applied to the launching construction of straight bridges. For the launching construction of curved beam bridges, the traditional launching process involves first launching along the tangent of the circular curve. When the deviation between the beam and the designed line reaches a limit, the horizontal jacks are adjusted to correct the deviation. This requires simultaneous launching and correction, which is quite difficult. The Hengqin Port Lotus Bridge (curve radius 55m) steel box girder was the first to use a differential launching process. During the curved launching process, through the differential launching control system, the inner and outer jacks have the same angular velocity but different linear velocity, resulting in a difference in launching stroke between the two sides of the jacks. However, differential jacking places high demands on equipment. For example, it requires multiple independent control loops to individually control each walking jack to achieve differential speed, or a central controller to control multiple loops, placing high performance demands on the central controller. This results in expensive jacking equipment and poor economic efficiency. Because the jacking method does not affect traffic underneath, it is widely used in overpass construction, such as newly built interchanges over existing highways. These are mostly straight bridges, with only ramps being curved. In actual construction, ordinary walking jacks are used for jacking straight bridges. For curved bridges, considering the smaller number and economic efficiency, the jacking setup used for straight bridges is generally adopted. Therefore, how to improve existing equipment to be suitable for jacking construction of both straight and curved bridges while maintaining good economic efficiency is an urgent problem to be solved. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides a simple and easy-to-construct differential jacking walking jack for curved bridges, and provides a jacking method for the differential jacking walking jack for curved bridges.

[0004] The technical solution of this invention to solve the above-mentioned technical problems is: a walking-type differential jack for curved bridges, comprising a first walking-type jack and a second walking-type jack. The first walking-type jack is arranged on the inner side of the curved bridge and includes a base, a longitudinal slide box, a transverse slide box, a vertical jack, and a plate rubber support. The longitudinal slide box is placed on the slide rail of the base, the transverse slide box is placed in the space of the longitudinal slide box and can only move laterally, and the vertical jack is placed in the space of the transverse slide box and can rotate freely to adapt to the rotation of the bridge during differential jacking. The plate rubber support is placed on the vertical jack and located under the bridge being jacked. When the plate rubber support is subjected to force, it undergoes shear deformation to adapt to the lateral displacement during differential jacking and to adjust the longitudinal displacement during differential jacking. The second walking-type jack is arranged on the outer side of the curved bridge. Compared with the first walking-type jack, the second walking-type jack does not include the plate rubber support, but the other structures are the same.

[0005] The aforementioned differential jacking walking jack for curved bridges includes a base plate, a slide rail, limit strips, an end plate, a jacking block, and a jacking jack. Two limit strips are symmetrically arranged on both sides of the slide rail, and the space between the two limit strips forms a slide rail. An end plate is provided on one side of the slide rail and is welded to the base plate. A jacking block is fixedly provided on the side of the end plate away from the slide rail. The jacking block has a hole in the middle, and a jacking jack is installed in the hole.

[0006] The aforementioned differential push walking jack for curved bridges has a base plate made of smooth stainless steel or polytetrafluoroethylene.

[0007] The aforementioned differential jacking walking jack for curved bridges includes a longitudinal sliding box comprising a longitudinal sliding box frame, a longitudinal sliding box space, longitudinal sliding box ear plates, a jack fixing block, and a jack. The longitudinal sliding box frame is a rectangular box structure with an open top, and the length of the longitudinal sliding box frame is the same as the distance between the two limiting strips on the base. A longitudinal sliding box ear plate is fixedly provided at the middle position of the long side of the longitudinal sliding box frame near the end plate. There are two longitudinal sliding box ear plates, which are arranged in parallel. There is a round hole in the middle of the longitudinal sliding box ear plate. The longitudinal sliding box frame is connected to the jacking jack through the longitudinal sliding box ear plates. The internal space of the longitudinal sliding box frame is the longitudinal sliding box space. A jack fixing block is welded at the middle position of the short side of one side of the longitudinal sliding box frame, and a jack is provided at the middle position of the jack fixing block.

[0008] The aforementioned curved bridge differential jacking walking jack includes a transverse sliding box comprising a transverse sliding box frame, a transverse sliding box space, and transverse sliding box ear plates. The transverse sliding box frame is a regular square prism, with the side length of the transverse sliding box frame being the same as the short side of the longitudinal sliding box space. The cylindrical space formed by the opening at the top of the transverse sliding box frame serves as the transverse sliding box space. A transverse sliding box ear plate is fixedly provided at the middle position on the side of the transverse sliding box frame near the correction jack. There are two transverse sliding box ear plates arranged in parallel, with a hole in the middle of each ear plate. The transverse sliding box frame is connected to the correction jack through the transverse sliding box ear plates.

[0009] The aforementioned differential jacking walking jack for curved bridges includes a vertical jack housing and a vertical jack piston. The vertical jack housing is cylindrical, and its diameter is the same as the inner diameter of the transverse sliding box space. The vertical jack piston is also cylindrical and is installed inside the vertical jack housing to adjust the vertical height of the bridge.

[0010] The aforementioned differential jacking walking jack for curved bridges includes a plate-type rubber support comprising a rubber block and a steel plate. The rubber block is a solid cylinder, and the steel plate is a circular steel plate with a diameter smaller than that of the rubber block. Multiple steel plates are evenly stacked and arranged inside the rubber block to reinforce it.

[0011] The aforementioned differential jacking walking jack for curved bridges includes a jack housing, a jack piston, a jack piston connecting rod, and a pin. Both the jack housing and the jack piston are cylindrical. The jack piston is installed inside the jack housing. The jack piston connecting rod is located at the end of the jack piston. A small hole is opened at the front end of the jack piston connecting rod, and the diameter of the small hole is the same as the diameter of the hole in the transverse sliding box ear plate. The pin passes through the small hole at the front end of the jack piston connecting rod and the hole in the transverse sliding box ear plate. The jack is fixedly connected to the transverse sliding box by the pin.

[0012] In the aforementioned curved bridge differential push walking jack, the diameter of the middle part of the pin is the same as the diameter of the small hole, while the diameter of the end of the pin is larger than the diameter of the small hole.

[0013] A method for using a walking jack to push a curved bridge at a differential speed includes the following steps:

[0014] Step 1: Design the placement of the walking jacks. Arrange 2 walking jacks in each group. Place the first walking jack inside the curved bridge and the second walking jack outside the curved bridge. The slide is along the arc secant line of the outer side of the curved bridge. The first walking jack and the second walking jack are arranged in parallel. Multiple groups of walking jacks are arranged longitudinally.

[0015] Step 2: Calculate the differential distance Δ1. The radius of the arc at the first step of the crawler jack position is R1, the radius of the arc at the second step of the crawler jack position is R2, and the longitudinal distance of a single push is D. Therefore, the differential distance is:

[0016]

[0017] Step 3: Calculate the vertical reaction force of the walking jacks during the jacking process of the curved bridge. Establish a finite element model of the curved bridge jacking construction, perform simulation analysis on the jacking process, obtain the vertical reaction force values ​​of each walking jack during the jacking process, and take the maximum value N of the vertical reaction force of the jacks according to their variation law. imax ;

[0018] Step 4: Based on the differential distance Δ1 and the maximum vertical reaction force N of the jack imax Design of plate rubber bearings:

[0019] 4-1) The maximum vertical reaction force N of the jack imax Design the area A of the plate rubber bearing;

[0020]

[0021] In the formula, σ is the actual compressive stress of the plate rubber bearing, and [σ] is the maximum allowable compressive stress of the plate rubber bearing;

[0022] 4-2) Design the thickness t of the rubber layer of the plate rubber bearing e ;

[0023] t e ≥2Δ1

[0024] Determine t e Then, the total thickness of the plate rubber bearing is obtained by setting the thickness of the middle single-layer rubber layer to 5mm, the thickness of the top and bottom rubber layers to 2.5mm, and the thickness of the steel plate to 2mm.

[0025] Step 5: Verify the performance of the plate rubber bearing;

[0026] 5-1) Calculate the shear stiffness k of the designed plate rubber bearing. G ;

[0027]

[0028] In the formula, G e The shear modulus of elasticity of the plate rubber bearing;

[0029] 5-2) Analyze the structural forces of the jacking unit during one stroke using a finite element model simulation, with the geometric nonlinearity option enabled during the analysis;

[0030] 5-3) Obtain the calculation results of the finite element model: displacement, stress, support reaction force, observe whether the displacement meets the differential distance, whether the stress is too large, and verify the anti-slip stability of the outer walking jack and the main beam.

[0031] H i <μN i

[0032] In the formula, H i N is the reaction force of the horizontal support for jacking calculated by the finite element model. i The vertical support reaction force due to self-weight is calculated using the finite element model, and μ is the friction coefficient between the walking jack and the main beam contact surface.

[0033] If the differential distance, stress, and anti-skid stability do not meet the requirements, the thickness of the rubber layer of the plate rubber bearing should be increased.

[0034] Step 6: Pre-launch verification of the accuracy of design parameters:

[0035] 6-1) Finite element model calibration and correction: The measured vertical support reaction force of the jack is compared with the self-weight vertical support reaction force calculated by the finite element model. If the relative error exceeds 10%, the finite element model is corrected to make the vertical support reaction force of the jack calculated by the finite element model close to the measured vertical support reaction force of the jack. The material density and elastic modulus of the structure are selected as correction parameters, and the measured vertical support reaction force of the jack is the target value. The two-parameter response surface method is used for model correction.

[0036] 6-2) The design of plate rubber bearings must be checked to ensure that the maximum bearing reaction force calculated by the corrected finite element model meets the bearing pressure requirement, and the actual measured bearing shear deformation Δ is compared with that of the bearing. 1c And the differential distance Δ1, if the ratio η=Δ1 / Δ 1c If the difference from 1 exceeds 10%, adjust the thickness of the rubber layer of the plate rubber bearing, taking η·t. e Redesign of plate rubber bearings;

[0037] Step 7: Formal jacking construction. The first step jack is placed on the bottom surface of the inner main beam of the curved bridge, and the second step jack is placed on the bottom surface of the outer main beam. The bridge is continuously jacked to the design position. During the jacking process, if the lateral deviation of the bridge exceeds the allowable value, lateral correction is performed. The second step jack on the bottom surface of the outer main beam pushes the bridge by one stroke D, and the outer main beam moves forward by a distance D. The first step jack on the bottom surface of the inner main beam pushes the bridge by one stroke D, and the plate rubber bearing undergoes shear deformation Δ1. The inner main beam moves forward by a distance D1, where D1 = D - Δ1. Through the shear deformation of the plate rubber bearing, the purpose of differential jacking of the curved bridge is achieved.

[0038] The beneficial effects of this invention are as follows: the invented walking jack for differential jacking of curved bridges can adapt to the rotation, lateral displacement and longitudinal differential displacement of the beam during the differential jacking process. Combined with the invented jacking method, the oil pump control system of ordinary walking jacks can be used to realize the differential jacking of curved bridges, achieving the ideal state in theory where almost no correction is needed. Furthermore, the length of the slide can be increased to increase the longitudinal distance of each jacking, reduce the number of jacking operations, and further improve the construction efficiency of curved bridge jacking. Attached Figure Description

[0039] Figure 1 This is a schematic diagram illustrating the principle of differential jacking of a curved bridge according to the present invention.

[0040] Figure 2 This is a three-dimensional structural diagram of the curved bridge differential jack walking type jack of the present invention.

[0041] Figure 3 This is a top view of the curved bridge differential jacking walking jack of the present invention.

[0042] Figure 4 This is a side view of the curved bridge differential jack walking type jack of the present invention.

[0043] Figure 5 This is a three-dimensional exploded view of the curved bridge differential jack walking type jack of the present invention.

[0044] Figure 6 This is a schematic diagram of the structure of the base of the present invention.

[0045] Figure 7 This is a schematic diagram of the longitudinal sliding box of the present invention.

[0046] Figure 8 This is a schematic diagram of the transverse sliding box of the present invention.

[0047] Figure 9 This is a schematic diagram of the vertical jack structure of the present invention.

[0048] Figure 10 This is a schematic diagram of the cross-sectional structure of the plate rubber bearing of the present invention.

[0049] Figure 11 This is a schematic diagram of the corrective jack of the present invention.

[0050] Figure 12 This is a plan view of the walking jack for the jacking construction of a curved bridge according to an embodiment of the present invention.

[0051] Figure 13 This is a transverse layout diagram of the walking jack for the jacking construction of a curved bridge according to an embodiment of the present invention.

[0052] Figure 14 This is a finite element model diagram of a curved bridge according to an embodiment of the present invention.

[0053] Figure 15 This is a schematic diagram of the jacking operation of a curved bridge according to an embodiment of the present invention.

[0054] Figure 16 This is a diagram of the vertical reaction force of the support in the finite element model of the curved bridge jacking condition 1 according to an embodiment of the present invention.

[0055] Figure 17 This is a diagram showing the vertical reaction force of the inner vertical jack in the jacking operation of a curved bridge according to an embodiment of the present invention.

[0056] Figure 18 This is a diagram showing the vertical reaction force of the outer vertical jack in the jacking operation of a curved bridge according to an embodiment of the present invention.

[0057] Figure 19 This is a diagram showing the displacement components of the outer walking jack along the outer arc for a stroke of 500mm in the curved bridge jacking condition 1 of this invention.

[0058] Figure 20 This is a schematic diagram of the curved bridge jacking operation 1 of the present invention, showing the displacement of 500mm by the walking jacks #4 and #8 along the outer arc. The thin line in the diagram is the structural line before deformation, and the thick line is the structural line after deformation.

[0059] Figure 21 This is a schematic diagram of a local displacement of 500mm by walking jacks #4 and #8 pushing the curved bridge under the working condition 1 of this invention.

[0060] Figure 22 This is a schematic diagram of the curved bridge jacking operation 1 of the present invention, showing the displacement of jacks 1# to 8# pushing along the outer arc for a stroke of 500mm. The thin line in the diagram is the structural line before deformation, and the thick line is the structural line after deformation.

[0061] Figure 23 This is a schematic diagram of a local displacement of 500mm as the walking jacks 1# to 8# push the curved bridge under the working condition 1 of this invention.

[0062] Figure 24 The structural stress diagram for the curved bridge jacking condition 1 of the present invention is shown below, which shows the walking jacks 1# to 8# pushing the bridge along the outer arc for a stroke of 500mm.

[0063] Figure 25 This is a diagram showing the reaction force of the support when the walking jacks #1 to #8 push the curved bridge under the following embodiment of the present invention, with a stroke of 500mm along the outer arc.

[0064] Figure 26This is a schematic diagram of the jacking operation of the curved bridge in embodiment 1 of the present invention, in which the walking jacks 1# to 8# push the bridge along the outer arc for a displacement of 500mm after adding a plate rubber support to the inner side. The thin line in the diagram is the structural line before deformation, and the thick line is the structural line after deformation.

[0065] Figure 27 This is a schematic diagram of the first local displacement of the curved bridge jacking condition 1 of the present invention, after adding a plate rubber support on the inner side. The walking jacks 1# to 8# push along the outer arc for a stroke of 500mm.

[0066] Figure 28 This is a schematic diagram of the second local displacement of the curved bridge jacking condition 1 of the present invention, after adding a plate rubber support on the inner side. The walking jacks 1# to 8# push along the outer arc for a stroke of 500mm.

[0067] Figure 29 This is a structural stress diagram of the curved bridge jacking condition 1 of the present invention, in which a plate rubber bearing is added to the inner side and the walking jacks 1# to 8# push the bridge along the outer arc for a stroke of 500mm.

[0068] Figure 30 This is a reaction force diagram of the walking jacks 1# to 8# pushing a support with a stroke of 500mm along the outer arc after adding a plate rubber support to the inner side of the curved bridge jacking condition 1 in the embodiment of the present invention.

[0069] Figure 31 This is a schematic diagram of the displacement of the outer beam during the jacking construction of a curved bridge according to an embodiment of the present invention.

[0070] Figure 32 This is a schematic diagram of the displacement of the inner beam during the jacking construction of a curved bridge according to an embodiment of the present invention. Detailed Implementation

[0071] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0072] like Figures 1-9As shown, a differential speed jacking walking jack for curved bridges includes a first walking jack and a second walking jack. The first walking jack is arranged on the inner side of the curved bridge. The first walking jack includes a base 11, a longitudinal slide box 12, a transverse slide box 13, a vertical jack 14, and a plate rubber support 15. The longitudinal slide box 12 is placed on the slide rail of the base 11, and the transverse slide box 13 is placed in the longitudinal slide box space 122. The transverse slide box 13 has a square plane, and the side length of the transverse slide box 13 is the same as the width of the longitudinal slide box space 122, ensuring that the transverse slide box 13 can only move laterally. The vertical jack 14 is a cylinder and is placed on the transverse slide box space 122. Within the sliding box space 132, the transverse sliding box space 132 is also a cylinder with the same diameter as the vertical jack 14, ensuring that the vertical jack 14 cannot produce translational displacement and can only rotate freely, adapting to the rotation of the bridge during differential jacking; the plate rubber bearing 15 is placed on the vertical jack 14 and located under the jacking bridge. When the plate rubber bearing 15 is under force, it undergoes shear deformation, adapting to the transverse displacement during differential jacking and realizing the adjustment of the longitudinal displacement during differential jacking; the second step jack is arranged on the outside of the curved bridge. Compared with the first step jack, the second step jack does not include the plate rubber bearing 15, but the other structures are the same.

[0073] like Figure 6 As shown, the base 11 includes a base plate 111, a slide rail 112, a limiting strip 113, an end plate 114, a jack fixing block 115, and a jack 116. Two limiting strips 113 are symmetrically arranged on both sides of the slide plate, and the space between the two limiting strips 113 forms the slide rail 112. An end plate 114 is provided on one side of the slide rail 112 and is welded to the base plate 111. A jack fixing block 115 is fixedly provided on the side of the end plate 114 away from the slide rail 112. The jack fixing block 115 has an opening in the middle, and a jack 116 is installed in the opening. The base plate 111 is made of smooth stainless steel plate or polytetrafluoroethylene plate.

[0074] like Figure 7As shown, the longitudinal sliding box 12 includes a longitudinal sliding box frame 121, a longitudinal sliding box space 122, a longitudinal sliding box ear plate 123, a correction jack fixing block 125, and a correction jack 124. The longitudinal sliding box frame 121 is a rectangular box structure with an opening at the top. The length of the longitudinal sliding box frame 121 is the same as the distance between the two limiting strips 113 on the base 11, ensuring that the longitudinal sliding box frame 121 does not produce lateral displacement, but produces longitudinal displacement under the action of the jacking jack 116 to push the bridge. The longitudinal sliding box frame 121 is close to... A longitudinal sliding box ear plate 123 is fixedly provided at the middle position of the long side on one side of the end plate 114. There are two longitudinal sliding box ear plates 123, which are arranged in parallel. There is a round hole in the middle of the longitudinal sliding box ear plate 123. The longitudinal sliding box frame 121 is connected to the jacking jack 116 through the longitudinal sliding box ear plate 123. The internal space of the longitudinal sliding box frame 121 is the longitudinal sliding box space 122. A correction jack fixing block 125 is welded at the middle position of the short side on one side of the longitudinal sliding box frame 121. A correction jack 124 is provided at the middle position of the correction jack fixing block 125.

[0075] like Figure 8 As shown, the transverse sliding box 13 includes a transverse sliding box frame 131, a transverse sliding box space 132, and a transverse sliding box ear plate 133. The transverse sliding box frame 131 is a regular square prism, and the side length of the transverse sliding box frame 131 is the same as the short side of the longitudinal sliding box space 122, ensuring that the transverse sliding box 12 does not produce longitudinal displacement, but produces transverse displacement under the action of the correction jack 124 to correct the bridge. The cylindrical space formed by the opening at the top of the transverse sliding box frame 131 serves as the transverse sliding box space 132. A transverse sliding box ear plate 133 is fixedly provided at the middle position on the side of the transverse sliding box frame 131 near the correction jack 124. There are two transverse sliding box ear plates 133, which are arranged in parallel. There is a hole in the middle of the transverse sliding box ear plate 133. The transverse sliding box frame 131 is connected to the correction jack 124 through the transverse sliding box ear plate 133.

[0076] like Figure 9 As shown, the vertical jack 14 includes a vertical jack housing 141 and a vertical jack piston 142. The vertical jack housing 141 is a cylinder, and its diameter is the same as the inner diameter of the transverse sliding box space 132, ensuring that the vertical jack 14 does not translate but only rotates freely, adapting to the bridge rotation during differential jacking. The vertical jack piston 142 is also a cylinder, but its diameter is smaller than that of the vertical jack housing 141. The vertical jack piston 142 is installed inside the vertical jack housing 141 to adjust the vertical height of the jacking bridge.

[0077] like Figure 10As shown, the plate rubber bearing 15 includes a rubber block 151 and a steel plate 152. The rubber block 151 is a solid cylinder, and the steel plate 152 is a circular steel plate with a diameter smaller than that of the rubber block 151. Multiple steel plates 152 are evenly stacked and arranged inside the rubber block 151 to reinforce the rubber block 151. Under horizontal load, the plate rubber bearing 15 can undergo shear deformation along the load direction. Through reasonable bearing design, it can adapt to the lateral displacement and longitudinal differential distance of the beam during differential jacking.

[0078] like Figure 11 As shown, the jacking 124 includes a jacking housing 1241, a jacking piston 1242, a jacking piston connecting rod 1243, and a pin 1244. Both the jacking housing 1241 and the jacking piston 1242 are cylindrical. The jacking piston 1242 is installed inside the jacking housing 1241. The jacking piston connecting rod 1243 is located at the end of the jacking piston 1242. A small hole is opened at the front end of the jacking piston connecting rod 1243. The diameter of the small hole is the same as the diameter of the hole in the transverse sliding box ear plate 133. The pin 1244 passes through the small hole at the front end of the jacking piston connecting rod 1243 and the hole in the transverse sliding box ear plate 133. The jacking 124 is fixedly connected to the transverse sliding box 13 through the pin 1244. The diameter of the middle part of the pin 1244 is the same as the diameter of the small hole, and the diameter of the end of the pin 1244 is larger than the diameter of the small hole.

[0079] A method for using a walking jack to push a curved bridge at a differential speed includes the following steps:

[0080] Step 1: Design the placement of the walking jacks. Arrange two walking jacks per group. The first walking jack is placed inside the curved bridge, and the second walking jack is placed outside the curved bridge. The slide rail 112 runs along the secant line of the outer arc of the curved bridge. The first and second walking jacks are arranged parallel to each other. Multiple groups of walking jacks are arranged longitudinally with appropriate spacing. Figure 12 The double narrow steel box girder curved bridge has a first step jack placed on the bottom surface of the inner main girder 31, a second step jack placed on the bottom surface of the outer main girder 32, and a set of step jacks placed longitudinally at intervals of 4 crossbeams 33 (crossbeam spacing of about 5m), for a total of 5 sets.

[0081] Step 2: As Figure 1In the diagram, O represents the center of the curved bridge, and R1 and R2 represent the radii of the arcs at the positions of the inner and outer jacks, respectively. The inner and outer jacks are placed at points n1 and n2, respectively, ideally pushing the jacks to points n3 and n4. However, the walking jacks can only move in straight lines; their pushing path is not along the arcs S1 and S2. Assuming the jack at n2 pushes along the secant line L1, and L2 is an inner arc secant line parallel to L1, the inner jack does not push along L2. This is because the initial distance between the inner and outer jacks is B, and this distance remains constant during the pushing process. When the outer jack reaches point n... i At point n, the inner jack is at n. j Point position, n j The point is located on line L4 and intersects with n i At the intersection of circles with center B and radius B, line L4 is the distance from point O to point n. i Connecting the points, at this point, it can be guaranteed that n i Point to n j The distance between the points is B, and the distances traveled by the inner and outer jacks also satisfy the differential speed ratio R1:R2, determined by each n. j The polyline formed by connecting points is denoted as L3, which is a curve. Since the jacking jacks can only be arranged along a straight line, the inner jacks can only be arranged along the secant line. At this time, the lateral distance Δ2 between L2 and L3 cannot be applied by ordinary walking jacks. At the same time, the beam will rotate significantly during the jacking process, as shown by angle θ in the figure. Ordinary walking jacks limit this rotation angle. When ordinary walking jacks are used for jacking, the outer jack travels a distance D to reach point n4, and the inner jack also travels a distance D to reach point n5. The distance between points n1 and n3 is D1, and the distance between points n3 and n5 is Δ1. D = D1 + Δ1. If the inner jack travels Δ1 less, it will be exactly on the arc, which satisfies the differential jacking requirement. The differential jacking method achieves the purpose of differential speed by controlling the travel distance of the inner and outer jacks.

[0082] Calculate the differential speed distance Δ1. Let the radius of the arc at the first step of the crawler jack position be R1, the radius of the arc at the second step of the crawler jack position be R2, and the longitudinal distance of a single push be D. Then the differential speed distance is:

[0083]

[0084] like Figure 13The inner main beam 31 and the outer main beam 32 are connected by a crossbeam 33. The first step jack is placed on the bottom surface of the inner main beam 31 and the top surface of the foundation 4, and the second step jack is placed on the bottom surface of the outer main beam 32 and the top surface of the foundation 4. The lateral distance between the inner main beam 31 and the outer main beam 32 is 5.8m. The radius of the curved bridge center circle is 150m. Therefore, R1 = 150 - 5.8 / 2 = 147.1m, R2 = 150 + 5.8 / 2 = 152.9m. The longitudinal distance of a single jacking is D = 500mm. The differential distance is:

[0085]

[0086] Step 3: Calculate the vertical reaction force of the walking jacks during the jacking process of the curved bridge, and establish a finite element model of the curved bridge jacking construction, such as... Figure 14 The jacking process was simulated and analyzed to obtain the vertical reaction force values ​​of each step jack during the jacking process. Figure 15 Taking the four jacking conditions in the example, Figure 15 The diagrams from top to bottom represent operating conditions 1, 2, 3, and 4. Figure 15 Numbers 1# to 10# represent the numbers of the 10 walking jacks. The vertical reaction force of the jacks in working condition 1 is as follows: Figure 16 As shown (unit: kN), the vertical reaction forces of the inner jacks under the four working conditions can be analyzed similarly as follows: Figure 17 The vertical reaction force of the outer jack is as follows: Figure 18 As shown in the diagram, the vertical reaction forces of the two sets of walking jacks (1#, 2# and 9#, 10#) along the longitudinal direction of the bridge vary significantly. For example, the vertical reaction force of jack 1# decreases from 600kN to 100kN. The vertical reaction forces of the middle jacks change relatively little, especially the middle set (5#, 6#), where the vertical reaction force remains almost unchanged at 500kN. The main consideration is the variation in the vertical reaction forces of the inner jacks. Figure 17 The maximum vertical reaction force N of the jack imax The value is set to 600kN.

[0087] Step 4: Based on the differential distance Δ1 and the maximum vertical reaction force N of the jack imax Design of plate rubber bearing 15:

[0088] 4-1) The maximum vertical reaction force N of the jack imax Design the area A of the plate rubber bearing;

[0089]

[0090] In the formula, σ is the actual compressive stress of the plate rubber bearing, and [σ] is the maximum allowable compressive stress of the plate rubber bearing, which is taken as [σ] = 10MPa;

[0091] According to step 3, the maximum vertical reaction force N of the jackimax =600kN, then

[0092]

[0093] When designed as a circular support, the diameter Φ≥276mm, and we take Φ=280mm.

[0094] 4-2) Design the thickness t of the rubber layer of the plate rubber bearing e ;

[0095] t e ≥2Δ1

[0096] The rubber layer needs to be of sufficient thickness to achieve the required shear deformation. e It should not exceed the diameter of the support, as an excessively high support will affect the stability of the operation.

[0097] Therefore:

[0098] t e ≥2Δ1=37.94mm

[0099] Take t e =60mm, single rubber layer thickness 5mm (top and bottom rubber layer thickness is 2.5mm), steel plate 152 thickness is 2mm, then there are a total of 12 steel plate 152 layers, 13 rubber layers, and the total thickness of plate rubber support 15 is 84mm.

[0100] Step 5: Verify the performance of the plate rubber bearing;

[0101] like Figure 19 For the jacking operation of a curved bridge, case 1, the displacement components (unit: mm) of the outer walking jacks are shown in the diagram. The jacks are pushed along the outer arc for a stroke D = 500 mm. It is assumed that only walking jacks #4 and #8 are used for jacking, and other support positions are frictionless and can slide freely. In the finite element model simulation analysis, the geometric nonlinearity option is enabled, and the calculated displacements are as follows: Figure 20 , Figure 20 The thin lines represent the structural lines before deformation, and the thick lines represent the structural lines after deformation. It can be seen that the inner and outer arcs basically overlap. The local displacement diagrams for positions #3 and #4 are shown below. Figure 21 As can be seen, the displacement of side #4 is approximately one jacking stroke D = 500 mm, and the displacement of side #3 is 481.035 mm. Considering the differential distance Δ1, the theoretical displacement of the inner arc is D - Δ1 = 500 - 18.97 = 481.033 mm, which is consistent with the calculation results of the finite element model. This indicates that if the frictional resistance during the jacking process is not considered, differential jacking can be achieved with only two walking jacks on the outer side.

[0102] In actual multi-point jacking, multiple ordinary walking jacks are used for synchronous jacking. Assuming the curved bridge jacking condition 1, walking jacks #1 to #8 jack along the outer arc for a stroke of 500mm (the jacking displacement of the inner #1 to #7 is the same as that of the outer #2 to #8), their displacements are as follows... Figure 22 In the diagram, the thin lines represent the structural lines before deformation, and the thick lines represent the structural lines after deformation. A schematic diagram of the local displacement at positions 3# and 4# is shown below. Figure 23 As can be seen, the crossbeams are not parallel before and after deformation. The structural stress diagram is as follows. Figure 24 The maximum stress is 304 MPa, which is very high. The support reaction force is as follows: Figure 25 As can be seen, there are large horizontal support reactions at each support position. For example, the horizontal reaction force of support #5 is 658kN, which is larger than the vertical reaction force of 507.5kN under its own weight. This indicates that the walking jacks #1 to #8 cannot push the main beam to the predetermined position because a large horizontal reaction force is generated between the walking jacks and the main beam, and horizontal sliding will occur between the two.

[0103] The above analysis is equivalent to a rigid connection between the walking jack and the main beam that restricts displacement in three directions. If a plate rubber support 15 is placed on the inner walking jack.

[0104] 5-1) Calculate the shear stiffness k of the designed plate rubber bearing. G ;

[0105]

[0106] In the formula, G e G is the shear modulus of elasticity of the plate rubber bearing. e =1MPa;

[0107] Using k G Finite element model calculations were performed using a stiffness of 1.03 kN / mm. For the curved bridge jacking condition 1, after adding a plate rubber bearing 15 on the inner side, the walking jacks #1 to #8 jacked the bridge along the outer arc for one stroke of 500 mm. The schematic diagram is shown below. Figure 26 In the diagram, the thin lines represent the structural lines before deformation, and the thick lines represent the structural lines after deformation. A schematic diagram of the local displacement at positions 3# and 4# is shown below. Figure 27 , Figure 28 It can be seen that the displacement of side #4 is approximately one jacking stroke D = 500mm, the jacking displacement of support #3 is 500mm, and the displacement of the main beam on side #3 is 481.9mm. This is consistent with the theoretical displacement of the inner arc considering the differential distance Δ1, which is D - Δ1 = 500 - 18.97 = 481.03mm. This indicates that the differential jacking effect was achieved through the plate rubber support 15. The structural stress is as follows: Figure 29 The maximum stress is 14.7 MPa, and the additional stress generated by the jacking is relatively small. The support reaction force is as follows: Figure 30It can be observed that the horizontal reactions of the inner supports #1, #3, #5, and #7 are all to the right and are similar in magnitude, approximately 18 kN. This is because the shear stiffness k of the plate rubber support 15... G =1.03kN / mm, so a shear deformation of 18.5mm is generated, which is basically consistent with the differential distance Δ1. However, it should be noted that the outer walking jack should not slide with the main beam, so that the main beam can be pushed to the predetermined position.

[0108] 5-2) Analyze the structural forces of the jacking unit during one stroke using a finite element model simulation, with the geometric nonlinearity option enabled during the analysis;

[0109] 5-3) Obtain the calculation results of the finite element model: displacement, stress, support reaction force, observe whether the displacement meets the differential distance, whether the additional stress of jacking is too large, and verify the anti-slip stability of the outer walking jack and the main beam.

[0110] H i <μN i

[0111] In the formula, H i N is the reaction force of the horizontal support for jacking calculated by the finite element model. i The vertical support reaction force due to self-weight is calculated using the finite element model. μ is the friction coefficient between the walking jack and the main beam contact surface. When rubber is in contact with steel, μ = 0.2.

[0112] For example, 4#, H i =45.1kN < μN i =0.2×369.8=73.96kN, which meets the requirements. If the differential distance, additional jacking stress, and anti-slip stability do not meet the requirements, the thickness of the rubber layer of the plate rubber bearing should be increased.

[0113] Step 6: Pre-launch verification of the accuracy of design parameters:

[0114] 6-1) Finite element model calibration and correction: The measured vertical support reaction force of the jack is compared with the self-weight vertical support reaction force calculated by the finite element model. If the relative error exceeds 10%, the finite element model is corrected to make the vertical support reaction force of the jack calculated by the finite element model close to the measured vertical support reaction force of the jack. The material density and elastic modulus of the structure are selected as correction parameters, and the measured vertical support reaction force of the jack is the target value. The two-parameter response surface method is used for model correction.

[0115] 6-2) The design of plate rubber bearings must be checked to ensure that the maximum bearing reaction force calculated by the corrected finite element model meets the bearing pressure requirement, and the actual measured bearing shear deformation Δ is compared with that of the bearing. 1c And the differential distance Δ1, if the ratio η=Δ1 / Δ 1cIf the difference from 1 exceeds 10%, adjust the thickness of the rubber layer of the plate rubber bearing, taking η·t. e Redesign of plate rubber bearings;

[0116] Step 7: Formal jacking construction. First-stage crawler jack 1 is placed on the bottom surface of the inner main beam 31 of the curved bridge, and second-stage crawler jack 2 is placed on the bottom surface of the outer main beam 32 of the curved bridge. Continuously jacking is performed until the design position is reached. During the jacking process, if the lateral deviation of the bridge exceeds the allowable value, lateral correction is carried out, such as... Figure 19 The second step-type jack 2 on the bottom surface of the outer main beam 32 of the curved bridge pushes it one stroke D, and the outer main beam 32 moves forward a distance D, as follows. Figure 20 When the bottom surface of the inner main beam 31 of the curved bridge is pushed by the first step of the crawler jack 1 for one stroke D, the plate rubber support 15 undergoes shear deformation Δ1, and the inner main beam 31 of the curved bridge moves forward by a distance D1, where D1 = D - Δ1. Through the shear deformation of the plate rubber support 15, the purpose of differential jacking of the curved bridge is achieved.

[0117] The above embodiments describe in detail that the first step jack 1 is arranged on the bottom surface of the inner main beam 31 of the curved bridge, and the second step jack 2 is arranged on the bottom surface of the outer main beam 32 of the curved bridge. They can also be arranged interchangeably. The plate rubber bearing 15 is designed in a similar manner as described above.

Claims

1. A method for jacking a curved bridge using a differential jacking walking jack, wherein the jacking walking jack includes a first walking jack and a second walking jack. The first walking jack includes a base, a longitudinal slide box, a transverse slide box, a vertical jack, and a plate rubber support. The plate rubber support is placed on the vertical jack and located under the bridge being jacked. When the plate rubber support is subjected to force, it undergoes shear deformation to adapt to the lateral displacement during the differential jacking process and to adjust the longitudinal displacement during the differential jacking process. Compared with the first-step crawler jack, the second-step crawler jack does not include a plate rubber support, but has the same other structure. Its characteristic feature is that it includes the following steps: Step 1: Design the placement position of the push-type walking jack. The first and second walking jacks form a group. The first walking jack is placed inside the curved bridge, and the second walking jack is placed outside the curved bridge. The slide of the base is along the arc secant direction of the outer side of the curved bridge. The first and second walking jacks are arranged in parallel, and multiple groups are arranged longitudinally. Step 2: Calculate the differential distance Δ1. The radius of the arc at the first step of the crawler jack position is R1, the radius of the arc at the second step of the crawler jack position is R2, and the longitudinal distance of a single push is D. Therefore, the differential distance is: ； Step 3: Calculate the vertical reaction force of the walking jacks during the jacking process of the curved bridge. Establish a finite element model of the curved bridge jacking construction, perform simulation analysis on the jacking process, obtain the vertical reaction force value of each step of the walking jacks during the jacking process, and take the maximum value N of the vertical reaction force of the jacks according to their variation law. imax ; Step 4: Based on the differential distance Δ1 and the maximum vertical reaction force N of the jack imax Design of plate rubber bearings: 4-1) The maximum vertical reaction force N of the jack imax Design the area A of the plate rubber bearing; ； In the formula, σ is the actual compressive stress of the plate rubber bearing, and [σ] is the maximum allowable compressive stress of the plate rubber bearing; 4-2) Design the thickness of the rubber layer of the plate rubber bearing ; ； Determine Then, the total thickness of the plate rubber bearing is obtained by setting the thickness of the middle single-layer rubber layer to 5mm, the thickness of the top and bottom rubber layers to 2.5mm, and the thickness of the steel plate to 2mm. Step 5: Verify the performance of the plate rubber bearing; 5-1) Calculate the shear stiffness of the designed plate rubber bearing ; ； In the formula, The shear modulus of elasticity of the plate rubber bearing; 5-2) Analyze the structural forces of the jacking unit during one stroke using a finite element model simulation, with the geometric nonlinearity option enabled during the analysis; 5-3) Obtain the calculation results of the finite element model: displacement, stress, support reaction force, observe whether the displacement meets the differential distance, whether the stress is too large, and verify the anti-slip stability of the second step jack and the main beam. ； In the formula, H i N is the reaction force of the horizontal support for jacking calculated by the finite element model. i The vertical support reaction force due to self-weight calculated using the finite element model. The coefficient of friction between the second step jack and the main beam contact surface; If the differential distance, stress, and anti-skid stability do not meet the requirements, the thickness of the rubber layer of the plate rubber bearing should be increased. Step 6: Pre-launch verification of the accuracy of design parameters; Step 7: Formal jacking construction.

2. The jacking method of the walking jack for differential jacking of curved bridges according to claim 1, characterized in that: The longitudinal sliding box is placed on the slide rail of the base, the transverse sliding box is placed in the longitudinal sliding box space and can only move laterally, and the vertical jack is placed in the transverse sliding box space and can rotate freely to adapt to the rotation of the bridge during differential jacking.

3. The jacking method of the walking jack for differential speed jacking of curved bridges according to claim 1, characterized in that: The base also includes a base plate, limiting strips, end plates, a jack fixing block, and a jack; two limiting strips are symmetrically arranged on both sides of the base plate, and the space between the two limiting strips forms a slide. An end plate is provided on one side of the slide, and the end plate is welded to the base plate. A jack fixing block is fixed on the side of the end plate away from the slide. The jack fixing block has a hole in the middle, and a jack is installed in the hole.

4. The jacking method of the walking jack for differential speed jacking of curved bridges according to claim 3, characterized in that: The base plate is made of smooth stainless steel or polytetrafluoroethylene.

5. The jacking method of the walking jack for differential jacking of curved bridges according to claim 3, characterized in that: The longitudinal slide box includes a longitudinal slide box frame, a longitudinal slide box space, a longitudinal slide box ear plate, a jack fixing block, and a jack. The longitudinal slide box frame is a rectangular box structure with an opening at the top. The length of the longitudinal slide box frame is the same as the distance between the two limiting strips on the base. A longitudinal slide box ear plate is fixedly installed at the middle position of the long side of the longitudinal slide box frame near the end plate. There are two longitudinal slide box ear plates, which are arranged in parallel. There is a round hole in the middle of the longitudinal slide box ear plate. The longitudinal slide box frame is connected to the jack through the longitudinal slide box ear plate. The internal space of the longitudinal slide box frame is the longitudinal slide box space. A jack fixing block is welded at the middle position of the short side of one side of the longitudinal slide box frame. A jack is installed at the middle position of the jack fixing block.

6. The jacking method of the walking jack for differential jacking of curved bridges according to claim 5, characterized in that: The transverse sliding box includes a transverse sliding box frame, a transverse sliding box space, and transverse sliding box ear plates. The transverse sliding box frame is a regular square prism, and the side length of the transverse sliding box frame is the same as the short side of the longitudinal sliding box space. The cylindrical space formed by the opening at the top of the transverse sliding box frame serves as the transverse sliding box space. A transverse sliding box ear plate is fixedly installed at the middle position on the side of the transverse sliding box frame near the straightening jack. There are two transverse sliding box ear plates, which are arranged in parallel. There is a hole in the middle of the transverse sliding box ear plates. The transverse sliding box frame is connected to the straightening jack through the transverse sliding box ear plates.

7. The jacking method of the walking jack for differential jacking of curved bridges according to claim 6, characterized in that: The vertical jack includes a vertical jack housing and a vertical jack piston. The vertical jack housing is cylindrical, and its diameter is the same as the inner diameter of the horizontal sliding box space. The vertical jack piston is also cylindrical and is installed inside the vertical jack housing to adjust the vertical height of the jacking bridge.

8. The jacking method of the walking jack for differential jacking of curved bridges according to claim 7, characterized in that: The plate-type rubber bearing includes a rubber block and a steel plate; the rubber block is a solid cylinder, and the steel plate is a circular steel plate with a diameter smaller than that of the rubber block. Multiple steel plates are evenly stacked and arranged inside the rubber block.

9. The jacking method of the walking jack for differential speed jacking of curved bridges according to claim 8, characterized in that: The jacking mechanism includes a jacking housing, a jacking piston, a jacking piston connecting rod, and a pin. Both the jacking housing and the jacking piston are cylindrical. The jacking piston is installed inside the jacking housing. The jacking piston connecting rod is located at the end of the jacking piston. A small hole is opened at the front end of the jacking piston connecting rod. The diameter of the small hole is the same as the diameter of the hole in the transverse sliding box ear plate. The pin passes through the small hole at the front end of the jacking piston connecting rod and the hole in the transverse sliding box ear plate. The jacking mechanism is fixedly connected to the transverse sliding box by the pin.

10. The jacking method of the walking jack for differential jacking of curved bridges according to claim 9, characterized in that: The diameter of the middle part of the pin is the same as the diameter of the small hole, and the diameter of the end of the pin is larger than the diameter of the small hole.

11. The jacking method of the walking jack for differential speed jacking of curved bridges according to claim 1, characterized in that: The process of step 6 is as follows: 6-1) Finite element model calibration and correction: The measured vertical support reaction force of the jack is compared with the self-weight vertical support reaction force calculated by the finite element model. If the relative error exceeds 10%, the finite element model is corrected to make the self-weight vertical support reaction force calculated by the finite element model close to the measured vertical support reaction force of the jack. The material density and elastic modulus of the structure are selected as correction parameters, and the measured vertical support reaction force of the jack is the target value. The two-parameter response surface method is used for model correction. 6-2) The design of plate rubber bearings must be checked to ensure that the maximum bearing reaction force calculated by the corrected finite element model meets the bearing pressure requirement, and the actual measured shear deformation of the bearings must be compared. and differential distance If the ratio If the difference from 1 exceeds 10%, adjust the thickness of the rubber layer of the plate rubber bearing. Redesign the plate rubber bearing.

12. The jacking method of the walking jack for differential speed jacking of curved bridges according to claim 1, characterized in that: In step 7, a first-stage crawler jack is placed on the bottom surface of the inner main beam of the curved bridge, and a second-stage crawler jack is placed on the bottom surface of the outer main beam. The beams are continuously pushed to the designed position. During the pushing process, if the lateral deviation of the bridge exceeds the allowable value, lateral correction is performed. The second-stage crawler jack on the bottom surface of the outer main beam pushes the beam one stroke D, moving the outer main beam forward a distance D. The first-stage crawler jack on the bottom surface of the inner main beam pushes the beam one stroke D, causing shear deformation of the plate rubber bearing. The inner main beam moves forward a distance D1, where D1 = D - The differential jacking of the curved bridge was achieved through the shear deformation of the plate rubber bearing.

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