A construction method suitable for municipal incremental launching bridge low-height beam falling

Abstract

This invention relates to the field of bridge engineering technology, specifically to a construction method suitable for low-height beam lowering of municipal jacking bridges. The method includes the following steps: Step 1: Constructing a low-elevation beam lowering pier next to a permanent pier, and installing multi-layer beam lowering flanges on top of the pier; installing multi-layer replacement flanges on top of the permanent pier; the permanent pier is higher than the beam lowering pier, and the lowered bridge is supported by the replacement flanges; the bridge is in an initial high position. Step 2: Installing a walking machine on top of the beam lowering flanges using a crane, and pre-setting pads on the lifting assembly of the walking machine. Step 3: Activating the lifting assembly through the hydraulic system, making the lifting assembly in a parallel lifting state, with the pads in contact with the bridge, allowing the lifting assembly to distribute the load on the bridge from the replacement flanges; by setting hydraulic jacks at the bottom of the walking machine, in conjunction with the hydraulic system, continuous low-height adjustment without disassembling the pads is achieved during the beam lowering process.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering technology, specifically relating to a construction method suitable for low-height beam lowering of municipal jacking bridges. Background Technology

[0002] When using the traditional bridge jacking method to lower beams from a high position, beam lowering equipment (walking machines and jacks) is set up on the piers. However, when the bridge is lowered to a point where it is only a short distance from the pier, the beam lowering equipment needs to be replaced with shorter jacks. At the bottom of the bridge, the construction space is narrow, making mechanical construction extremely inconvenient.

[0003] Among them, the invention patent with authorization announcement number CN109537460B discloses "a method for high-level bridge beam lowering construction". This method involves using a walking machine to lift the bridge and place the entire bridge weight on replacement piers; then, the vertical jacks of the walking machine retract, lifting the walking machine and removing the top beam lowering pier flange. The walking machine is then lowered and installed onto a new top beam lowering pier flange. Multiple layers of pads are installed on the temporary supports of the walking machine and the vertical jacks, ensuring the height of the pads matches the height of the first section of the beam lowering pier flange. Finally, the vertical jacks of the walking machine lift the bridge upwards, and the top replacement pier flange is removed. This method significantly reduces the workload of dismantling and installing the beam lowering equipment, reduces personnel consumption, and improves the efficiency of beam lowering construction.

[0004] Although this method uses vertical jacks to extend and retract in units of one pad thickness to gradually lower the height, it still requires manual removal of multiple layers of pads on the walking machine during beam lowering. In addition, after each removal of the beam lowering flange, multiple layers of pads need to be reinstalled on the walking machine, and then removed one by one in sequence to complete the beam lowering work. This process is not only cumbersome to operate, with a high workload and manpower consumption, but also poses a significant safety risk due to the frequent removal and installation of pads in a confined space, making it difficult to meet the construction needs of low-height beam lowering conditions. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a construction method suitable for low-height beam lowering of municipal bridges by jacking. By installing hydraulic jacks at the bottom of the walking machine, in conjunction with the hydraulic circuit unit and hydraulic system, continuous low-height adjustment can be achieved during the beam lowering process without the need to disassemble or assemble the pads.

[0006] The objective of this invention can be achieved through the following technical solutions: A construction method suitable for low-height beam lowering in municipal jacking bridges includes the following steps: Step 1: Construct a low-elevation beam-dropping pier next to the permanent pier, and install multi-layer beam-dropping flanges on the top of the beam-dropping pier; install multi-layer replacement flanges on the top of the permanent pier; the permanent pier is higher than the beam-dropping pier, and the bridge is lowered to be supported by the replacement flanges; the bridge is in its initial high position, ready to continue to be lowered step by step. Step 2: Install the walking machine on the top of the beam flange using a crane, and pre-set a pad on the walking machine lifting assembly; Step 3: Start the lifting assembly through the oil circuit unit to put the lifting assembly in a parallel lifting state, so that the pad plate contacts the bridge and the lifting assembly distributes the load on the bridge from the replacement flange. Step 4: Use the hydraulic system to lift the bridge by using the main support of the jacking assembly; let the main support bear the entire weight of the bridge; remove the topmost replacement flange; Step 5: The main support component is retracted through the oil circuit unit and returned to a parallel state, and the bridge weight is then supported by the three-support structure of the jacking assembly. Step 6: The auxiliary support component is retracted by one unit stroke through the hydraulic circuit unit, at which point it is supported by the main support component alone; Step 7: The main support component is retracted by one unit stroke through the oil circuit unit, at which point it is supported by the main and auxiliary support components. Step 8: Repeat steps 6 and 7 until the bridge is in contact with the new replacement flange again; Step 9: The bridge is supported by the top replacement flange and the lifting assembly. The lifting assembly continues to retract, leaving a lifting gap. The walking machine and the lifting assembly are lifted using a crane chain hoist. The lowering flange located below the walking machine is removed, and the walking machine and the lifting assembly are lowered again. Step 10: Repeat steps 3-9 until the bridge and the top of the permanent pier are in contact to complete the beam lowering. Remove the lower-elevation beam lowering pier and clean up all temporary facilities and equipment on site to ensure that the permanent pier structure is intact and undamaged.

[0007] As a further embodiment of the present invention, in step six, the lifting assembly consists of two sets of symmetrical secondary support members and a single set of main support members. The main support member is located between the two sets of secondary support members. The main support member includes a main beam jack cylinder, a main beam jack telescopic rod, and a main beam pad. One end of the main beam jack telescopic rod is slidably connected to the main beam jack cylinder, and the other end is fixed to the main beam pad. The secondary support member includes a side jack cylinder, a side jack telescopic rod, and a side pad. One end of the side jack telescopic rod is slidably connected to the side jack cylinder, and the other end is fixed to the side pad.

[0008] As a further embodiment of the present invention, in step six, the oil circuit unit includes an oil storage tank, an oil outlet pipe, and a connecting pipe; the oil storage tank is located on one side of the main beam jack cylinder body, and an oil pump is also provided in the oil storage tank; oil outlet pipes are provided between both ends of the oil storage tank and the two side jack cylinder bodies; and a connecting pipe is provided between the main beam jack cylinder body and the oil storage tank.

[0009] As a further embodiment of the present invention, both the oil outlet pipe and the connecting pipe are equipped with a closing valve.

[0010] As a further aspect of the present invention, the main beam jack cylinder, the side jack cylinder, and the oil storage tank are equipped with oil pressure sensors and liquid level sensors that are connected to the oil circuit system. The coordinated control of the oil circuit unit and the lifting assembly is achieved through the oil circuit system, and the control information of the oil circuit system is obtained from the information collected by the oil pressure sensors and liquid level sensors.

[0011] As a further aspect of the present invention, during the support stage, the main support member and the auxiliary support member are alternately operated, and the ratio of the jack load forces between the two is 1:2.

[0012] As a further embodiment of the present invention, the area ratio of the main beam pad plate to the side pad plate is 1:2.

[0013] As a further aspect of the present invention, a detection component is also included, comprising a square frame, a detection rod, a telescopic spring, a ball, and a pressure sensor; the square frame is horizontally fixed to the top of the jack cylinder, the detection rod extends horizontally through the interior of the square frame, one end of which is semi-circular and rotatably connected to the ball, and the other end is in contact with the pressure sensor located on the side wall of the square frame via the telescopic spring.

[0014] The beneficial effects of this invention are as follows: 1. Through the continuous retraction and lifting action of the lifting components, combined with the coordinated control of hydraulic jacks with interconnected oil circuits, the bridge load is smoothly transferred between the lowering flange and the replacement flange, avoiding the safety risks and precision loss caused by frequent disassembly and assembly of pads in traditional construction; the millimeter-level adjustment capability significantly improves the accuracy of lowering the beam and the construction efficiency, and is especially suitable for municipal bridge projects with limited space, effectively ensuring structural safety and construction continuity.

[0015] 2. By cooperating with the hydraulic circuit unit and the lifting assembly, and combining sensors to monitor the pressure and displacement data of each support point in real time, the system can perform refined step control and multi-point collaborative monitoring. In each round of stroke adjustment, the system collects pressure and displacement data in real time, and combines the real-time feedback from the displacement sensor and pressure transmitter to automatically correct the stroke deviation of each support point, ensuring the overall displacement consistency. Attached Figure Description

[0016] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a parallel state diagram of the lifting component of the present invention; Figure 2 This is a diagram showing the state of the topmost replacement flange after removal. Figure 3 This is a schematic diagram of the lifting assembly and oil circuit unit of the present invention; Figure 4 This is a schematic diagram of the oil circuit unit of the present invention; Figure 5 This is the offset detection diagram of the present invention; Legend: A. Bridge; B. Permanent pier; 11. Replacement flange; C. Beam lowering pier; 21. Beam lowering flange; D. Walking machine; 31. Side jack cylinder; 32. Side jack telescopic rod; 33. Side pad; 34. Main beam jack cylinder; 35. Main beam jack telescopic rod; 36. Main beam pad; 41. Oil reservoir; 42. Oil outlet pipe; 44. Connecting pipe; 5. Square frame; 51. Detection rod; 52. Telescopic spring; 53. Ball; 54. Pressure sensor. Detailed Implementation

[0018] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0019] Example 1: This example refers to... Figures 1-5 As shown, a construction method suitable for low-height beam lowering of municipal bridges is disclosed, including the following steps: Step 1: Construct a low-elevation beam-dropping pier C next to permanent pier B, and install a multi-layer beam-dropping flange 21 on top of beam-dropping pier C; install a multi-layer replacement flange 11 on top of permanent pier B; permanent pier B is higher than beam-dropping pier C, and the bridge A is lowered under the load of replacement flange 11; bridge A is in its initial high position and is ready to continue to be lowered step by step.

[0020] Step 2: Install the walking machine D on the top of the drop beam flange 21 using a crane, and pre-set a pad on the lifting assembly of the walking machine D; Step 3: Start the lifting assembly through the oil circuit unit to make the lifting assembly in a parallel lifting state, so that the pad plate contacts the bridge A, and the lifting assembly distributes the load of the replacement flange 11 on the bridge A. Step 4: Use the hydraulic system to lift the main support of the jacking assembly to lift bridge A; let the main support bear the entire weight of bridge A; remove the topmost replacement flange 11; Step 5: The main support component is retracted through the oil circuit unit and returned to a parallel state, and the weight of bridge A is then borne by the three-support form of the lifting assembly. Step 6: The auxiliary support component is retracted by one unit stroke through the hydraulic circuit unit, at which point it is supported by the main support component alone; Step 7: The main support component is retracted by one unit stroke through the oil circuit unit, at which point it is supported by the main and auxiliary support components. Step 8: Repeat steps 6 and 7 until bridge A is in contact with the new replacement flange 11 again; Step 9: The bridge A is supported by the top replacement flange 11 and the lifting assembly. The lifting assembly continues to retract, leaving a lifting gap. The walking machine D and the lifting assembly are lifted using a crane chain hoist. The beam-dropping flange 21 located below the walking machine D is removed, and the walking machine D and the lifting assembly are lowered again. Step 10: Repeat steps 3-9 until the top of bridge A and permanent pier B are in contact to complete the beam lowering, and remove the lower-elevation beam lowering pier C and clean up all temporary facilities and equipment on site to ensure that the permanent pier B structure is intact and undamaged.

[0021] Steps 3 to 5 remove the top replacement flange 11; steps 6 to 8 combine the jacking assembly and the oil circuit unit to gradually reduce the height of bridge A, thus overcoming the problems of difficulty in installing and removing existing multi-layer pads and the time and effort required when using them in the low-to-high distance between bridge A and permanent pier B.

[0022] In step six, the jacking assembly consists of two sets of symmetrical auxiliary supports and a single set of main supports. The main support is located between the two sets of auxiliary supports and includes a main beam jack cylinder 34, a main beam jack telescopic rod 35, and a main beam pad 36. One end of the main beam jack telescopic rod 35 is slidably connected to the main beam jack cylinder 34, and the other end is fixed to the main beam pad 36. The auxiliary supports include a side jack cylinder 31, a side jack telescopic rod 32, and a side pad 33. One end of the side jack telescopic rod 32 is connected to the side jack cylinder 34. The jack cylinder 31 is slidably connected, and the other end is fixed to the side pad 33. During the support stage, the main support and the auxiliary support are alternately supported. The ratio of the jack load force between the two is 1:2, so that the load capacity of the main support and the two auxiliary support of bridge A is consistent. The area ratio of the side pad 33 or the main beam pad 36 is 1:2, and the contact area is the same. The alternating support avoids long-term independent support of bridge A, which may cause structural stress concentration or local deformation, and ensures uniform and stable load transfer. In step six, the oil circuit unit includes an oil storage tank 41, an oil outlet pipe 42, and a connecting pipe 44. The oil storage tank 41 is located on one side of the main beam jack cylinder 34, and an oil pump is also installed inside the oil storage tank 41. Oil outlet pipes 42 are installed between both ends of the oil storage tank 41 and the two side jack cylinders 31. A connecting pipe 44 is installed between the main beam jack cylinder 34 and the oil storage tank 41. Both the oil outlet pipe 42 and the connecting pipe 44 are equipped with closing valves. Through the above arrangement, a flow control is formed between the main beam jack cylinder 34, the side jack cylinder 31, and the oil storage tank 41. The closing valve is controlled by the oil circuit system and its on / off state can be adjusted. In addition, the main beam jack cylinder 34, the side jack cylinder 31, and the oil storage tank 41 are equipped with oil pressure sensors and liquid level sensors that are connected to the oil circuit system. The coordinated control of the oil circuit unit and the lifting assembly is realized through the oil circuit system. The control information of the oil circuit system is obtained from the information collected by the oil pressure sensors and liquid level sensors.

[0023] In step three, the lifting assembly is started for the first time. The oil circuit system controls the opening of two closed valves. The oil storage tank 41 supplies oil to the main beam jack cylinder 34 and the side jack cylinder 31 through the oil pump. The main support and auxiliary support of the lifting assembly extend synchronously. The main beam pad 36 and the side pad 33 contact the bottom of the bridge A to form a three-point support, so as to realize the smooth lifting of the bridge A and gradually transfer the load to the lifting assembly, ensuring that the structure is subjected to uniform force without impact. In addition, in other steps, the starting and retraction of the main and auxiliary support components are controlled by the oil circuit system, just like the opening and closing of the closed valves.

[0024] To provide a more intuitive understanding of the coordinated changes of various components during the jacking process, the following data table is provided. The table records the stroke changes of the main beam jack telescopic rod 35 and the side jack telescopic rod 32 and the corresponding hydraulic circuit status during each stage of the jacking process. The table tentatively defines the jacking assembly as having a parallel state of 4 unit strokes, with 4 unit strokes for the main support and auxiliary support components as a reference. Figure 1 The numbers on the left (N, 1, 2, 3) and the numbers on the right (1, 2, 3) require further explanation. Figure 1 The numbers (N, 1, 2, 3) on the left represent the quantity. In the attached diagram, B is a permanent pier, and 11 is a replacement flange. This indicates that (N, 1, 2, 3) represent the quantity, specifically replacement flange 11. However, this data can be adjusted according to the actual travel distance. Specifically, the lowering distance of bridge A varies each time, and N represents the number of flanges that can be added to accommodate the changed travel distance. N can represent multiple quantities or a single quantity. For example, if bridge A is lowered too high and requires adding "4, 5, 6, 7," then N represents "4, 5, 6, 7." Furthermore... Figure 1 The numbers on the right are (1, 2, 3); where the attached figure number 21 represents the drop beam flange 21, and the vertical numbers 1, 2, 3 represent the number of drop beam flanges 21; the attached figure number D represents the walking machine; steps 61, 62, 71, and 72 in the table correspond to steps six or seven respectively; specifically, step 61 is the first set of repeated steps of step six, step 71 is the first set of repeated steps of step seven, step 62 is the second set of repeated steps of step six, and step 72 is the second set of repeated steps of step seven.

[0025] Data table:

[0026] As shown in the table above, the jacking process achieves smooth transfer and precise adjustment of the load on bridge A by controlling the extension and retraction strokes of the main and auxiliary support components in stages. The stroke changes are progressive and cyclical, with each stage alternating between three-support or single-support modes to ensure structural stability, avoid stress concentration, and also serve as backup safety supports. When the main or auxiliary support component works alone, the other group remains locked to ensure that the bridge A structure remains under controlled support in case of emergencies; this avoids errors in the amount of oil retraction due to load during oil retraction. The entire jacking process strictly follows the principle of main support first, then auxiliary support, with alternating retraction, and maintains real-time adjustment of the oil supply based on oil pressure feedback to control the stroke error of each jack within ±2mm, ensuring synchronization accuracy.

[0027] The hydraulic system adjusts the oil supply pressure and flow rate in real time based on sensor feedback to ensure synchronized expansion and contraction, improving operational safety and control accuracy. It also dynamically adjusts the closed valve state based on sensor feedback to ensure synchronized action and pressure balance. The entire process, from initial synchronized lifting to gradual, staged descent, forms a closed-loop control, ultimately completing the lifting task and safely returning to its original position. This fully demonstrates the high degree of unity between system coordination and control precision. Through refined step control and multi-point collaborative monitoring, the system collects pressure and displacement data in real time during each stroke adjustment. Combined with real-time feedback from displacement sensors and pressure transmitters, it automatically corrects stroke deviations at each support point, ensuring overall displacement consistency.

[0028] Example 2: Based on Example 1, with reference to Figures 4-5 As shown, this invention also proposes Embodiment 2. Since the lifting assembly faces the risk of displacement during the lifting of the large-tonnage bridge A, this embodiment proposes a detection component to effectively address this risk. This component is used to monitor the displacement deviation of the main and auxiliary support components in real time. Specifically, it detects the verticality of the main beam jack extension rod 35 and the side jack extension rod 32. Each support component is laterally equipped with a detection component. All three detection components are connected to the hydraulic system, feeding back the collected data to the hydraulic system. The detection component includes a square frame 5, a detection rod 51, a telescopic spring 52, a ball 53, and a pressure sensor 54. The square frame 5 is laterally fixed to the jack. At the top of the cylinder body, the detection rod 51 extends horizontally through the interior of the square frame 5. One end of the rod is semi-circular and rotatably connected to a ball 53 to eliminate some friction. The other end is in contact with a pressure sensor 54 located on the side wall of the square frame 5 via a telescopic spring 52. The ball 53 is in contact with the outer surface of the main beam or the telescopic rod 32 of the side jack. When the detection rod 51 tilts, the ball 53 is squeezed, causing the detection rod 51 to move against the spring force, so that the pressure sensor 54 detects the pressure change and thus determines the verticality deviation of the telescopic rod. After receiving this signal, the hydraulic system feeds it back to the hydraulic system, realizing real-time detection of the status of the lifting component during the gradual lowering of the beam.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A construction method suitable for low-height beam lowering in municipal jacking bridges, characterized in that: Includes the following steps: Step 1: Construct a low-elevation beam-dropping pier next to the permanent pier, and install multi-layer beam-dropping flanges on the top of the beam-dropping pier; install multi-layer replacement flanges on the top of the permanent pier; the permanent pier is higher than the beam-dropping pier, and the bridge is lowered to be supported by the replacement flanges; the bridge is in its initial high position, ready to continue to be lowered step by step. Step 2: Install the walking machine on the top of the beam flange using a crane, and pre-set a pad on the walking machine lifting assembly; Step 3: Start the lifting assembly through the oil circuit unit to put the lifting assembly in a parallel lifting state, so that the pad plate contacts the bridge and the lifting assembly distributes the load on the bridge from the replacement flange. Step 4: Use the hydraulic system to lift the bridge by using the main support of the jacking assembly; let the main support bear the entire weight of the bridge; remove the topmost replacement flange; Step 5: The main support component is retracted through the oil circuit unit and returned to a parallel state, and the bridge weight is then supported by the three-support structure of the jacking assembly. Step 6: The auxiliary support component is retracted by one unit stroke through the hydraulic circuit unit, at which point it is supported by the main support component alone; Step 7: The main support component is retracted by one unit stroke through the oil circuit unit, at which point it is supported by the main and auxiliary support components. Step 8: Repeat steps 6 and 7 until the bridge is in contact with the new replacement flange again; Step 9: The bridge is supported by the top replacement flange and the lifting assembly. The lifting assembly continues to retract, leaving a lifting gap. The walking machine and the lifting assembly are lifted using a crane chain hoist. The lowering flange located below the walking machine is removed, and the walking machine and the lifting assembly are lowered again. Step 10: Repeat steps 3-9 until the bridge and the top of the permanent pier are in contact to complete the beam lowering. Remove the lower-elevation beam lowering pier and clean up all temporary facilities and equipment on site to ensure that the permanent pier structure is intact and undamaged.

2. The construction method for low-height beam lowering of municipal jacking bridges according to claim 1, characterized in that: In step six, the lifting assembly consists of two sets of symmetrical auxiliary support members and a single set of main support members. The main support member is located between the two sets of auxiliary support members. The main support member includes a main beam jack cylinder, a main beam jack telescopic rod, and a main beam pad. One end of the main beam jack telescopic rod is slidably connected to the main beam jack cylinder, and the other end is fixed to the main beam pad. The auxiliary support member includes a side jack cylinder, a side jack telescopic rod, and a side pad. One end of the side jack telescopic rod is slidably connected to the side jack cylinder, and the other end is fixed to the side pad.

3. The construction method for low-height beam lowering of municipal jacking bridges according to claim 2, characterized in that: In step six, the oil circuit unit includes an oil storage tank, an oil outlet pipe, and a connecting pipe. The oil storage tank is located on one side of the main beam jack cylinder body. An oil pump is also installed in the oil storage tank. Oil outlet pipes are installed between both ends of the oil storage tank and the two side jack cylinder bodies. A connecting pipe is installed between the main beam jack cylinder body and the oil storage tank.

4. The construction method for low-height beam lowering of municipal jacking bridges according to claim 3, characterized in that: Both the oil outlet pipe and the connecting pipe are equipped with closing valves.

5. The construction method for low-height beam lowering of municipal jacking bridges according to claim 3, characterized in that: The main beam jack cylinder, the side jack cylinder, and the oil storage tank are equipped with oil pressure sensors and liquid level sensors that are connected to the oil circuit system. The coordinated control of the oil circuit unit and the lifting assembly is achieved through the oil circuit system, and the control information of the oil circuit system is obtained from the information collected by the oil pressure sensors and liquid level sensors.

6. The construction method for low-height beam lowering of municipal jacking bridges according to claim 2, characterized in that: During the support phase, the main support and the auxiliary support alternate, and the ratio of the jack load forces between the two is 1:

2.

7. The construction method for low-height beam lowering of municipal jacking bridges according to claim 2, characterized in that: The area ratio of the main beam pad plate to the side pad plate is 1:

2.

8. The construction method for low-height beam lowering of municipal jacking bridges according to claim 2, characterized in that: It also includes a detection component, which includes a square frame, a detection rod, a telescopic spring, a ball, and a pressure sensor. The square frame is horizontally fixed to the top of the jack cylinder. The detection rod runs horizontally through the inside of the square frame. One end of the rod is semi-circular and rotatably connected to the ball. The other end contacts the pressure sensor located on the side wall of the square frame through the telescopic spring.

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