Upward self-propelled mobile formwork pre-pressing construction method

Abstract

The present invention discloses a pre-stressing construction method for an upward self-propelled mobile formwork. When pre-stressing the mobile formwork, sand bags and precast concrete blocks are used as the load form. According to the cross-sectional shape of the box beam and the different clamping ratios of the pre-stressing load, the number of precast concrete blocks is increased by hoisting, and the blocks are evenly arranged and laid in layers along the bridge direction. The precast concrete blocks are arranged into two structures including Class A pre-stressing blocks and Class B pre-stressing blocks. The precast concrete blocks themselves are convenient for stacking and standardized prefabrication, and a slot is opened in the middle of the top. U-shaped or straight steel bars are arranged in the slot to facilitate the hoisting of the precast concrete blocks, thereby greatly improving the efficiency of the pre-stressing loading construction as a whole.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and more particularly to a method for pre-pressing a construction method of an upward self-propelled movable formwork. Background Art

[0002] The mobile formwork is a mechanical structure with its own formwork, which uses abutments or piers as supports for on-site pouring of bridges. It is widely used in the construction of continuous beams of highway bridges and railway bridges. After the mobile formwork is assembled, it must be pre-stressed to eliminate the inelastic deformation of the mobile formwork assembly, calculate the elastic deformation during construction load, and calculate the pre-arch of the mobile formwork bottom formwork based on the upper arch after the box beam is tensioned. The safety performance of the formwork can be tested at the same time through pre-stressing. However, sand bags or water bags are currently more commonly used in the pre-stressing process. The shapes of the two are relatively difficult to control, especially water bags, which have the risk of breaking. After calculating the pre-stressing weight required for different areas of the box beam, the weight needs to be increased for graded pre-stressing. Sand bags or water bags are not easy to stack stably, and it is also difficult to adjust their position using the lifting trolley on the mobile formwork, resulting in low overall construction efficiency of the entire pre-stressing construction. Summary of the Invention

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0004] Another object of the present invention is to provide an upward self-propelled mobile formwork pre-pressing construction method to solve the technical problems of inconvenient and low efficiency in the mobile formwork pre-pressing construction in the prior art.

[0005] In order to achieve these objects and other advantages according to the present invention, a construction method for pre-stressing a self-propelled upward movable formwork is provided, in which a pre-stressing method of precast concrete blocks + sandbags is adopted on the movable formwork. According to the cross-sectional shape of the box girder, an equal load effect is achieved with high beam ends and low mid-span. In the cross-sectional direction of the box girder, the flange plates of the corresponding box girder are pre-stressed with sandbags, and the web plates and top and bottom plates of the corresponding box girder are pre-stressed with precast concrete blocks.

[0006] Preferably, the precast concrete blocks include Class A precast blocks and Class B precast blocks, and both Class A precast blocks and Class B precast blocks are C20 concrete precast blocks and are in the shape of quadrangular prisms.

[0007] Preferably, the bottom side length of the Class A pre-compression block is 120 cm and the height is 75 cm, the bottom side length of the Class B pre-compression block is 120 cm and the height is 30 cm, and a cubic slot with a side length of 20 cm is provided downward at the top center of the Class A pre-compression block and the Class B pre-compression block respectively. Two U-shaped steel bars are arranged downwardly in the slot of the Class A pre-compression block aligned with the center line, and the two U-shaped steel bars are arranged perpendicular to each other in the horizontal plane. The two ends of the U-shaped steel bars are 50 cm long and the middle is 80 cm long. The height difference between the top of the U-shaped steel bar and the top of the slot is 10 cm. Two straight steel bars are arranged in the slot of the Class B pre-compression block aligned with the center line and perpendicular to each other along the horizontal direction. The straight steel bars are 100 cm long and the height difference with the top of the slot is 10 cm.

[0008] Preferably, the preloading load is divided into three levels according to 60%, 100% and 120% of the maximum construction load, and the holding time of the three levels of loading is not less than 2h, 2h and 8h respectively. During the preloading process, the settlement of the movable formwork is observed, and the deformation is deemed stable when the difference between the observed deformation values ​​is less than 2mm.

[0009] Preferably, a 32m box girder is cast in situ on the movable formwork, and the box girder is divided into three areas along the length direction, wherein the first area is symmetrically located at both ends of the box girder and has a length of 1.5m, the second area is symmetrically located on the inner side of the first area and has a length of 3m, and the third area is set between the two second areas, and the first area, the second area, and the third area are pre-loaded with 60%, 100%, and 120% of the maximum construction load respectively.

[0010] Preferably, the weight of each sandbag is set to 1.5t. When the web, top and bottom plates of the corresponding box girder are pre-stressed with precast concrete blocks, the Class A pre-stressed blocks are arranged in priority, and the remaining load is supplemented by the Class B pre-stressed blocks. All the Class A pre-stressed blocks and the Class B pre-stressed blocks in each layer are evenly placed and the axes of symmetry are aligned along the bridge direction.

[0011] Preferably, when stacking the Class A pre-compression blocks, an auxiliary positioning platform is provided to assist in adjusting the horizontal position of the Class A pre-compression blocks in the transverse direction of the bridge, and the auxiliary positioning platform is provided on the Class A pre-compression blocks located in the middle of the top and bottom plates of the corresponding box beams and in the same horizontal plane, comprising:

[0012] The platform plate is a horizontally arranged square structure with a width and length covering at least two of the Class A pre-loaded blocks. The bottom surface of the platform plate is a sliding surface. A first partition is provided downwardly in the middle of the platform plate. A downwardly telescopic pushing cylinder is provided inside the first partition. The telescopic end of the pushing cylinder is connected to a second partition. The second partition is consistent in size with the first partition, and the first and second partitions are respectively provided with universal wheel sets on the left and right sides in the longitudinal direction of the bridge. The thickness of the first partition plus the universal wheel sets on both sides in the transverse direction of the bridge is consistent with the setting spacing of the two adjacent Class A pre-loaded blocks in the middle. A hook is provided on the edge of the top surface of the platform plate.

[0013] Elastic airbags are respectively arranged downwardly at both ends of the platform plate in the transverse direction of the bridge, and the elastic airbags extend along the longitudinal direction of the bridge and downwardly to the bottom of one of the Class A pre-compression blocks. An air inlet connected to the elastic airbag is provided at the top corner of the platform plate corresponding to the elastic airbag, and the air inlet is connected to the air pump;

[0014] The limit assembly is symmetrically provided with four at the bottom of the platform plate, including limit slots extending along the diagonal direction of the platform plate, one limit slot corresponds to one of the slot holes, and the limit slot is divided into two layers connected to each other, wherein the width of the upper layer is greater than the width of the lower layer, and the lower layer of the limit slot is slidably connected to a vertically arranged limit rod, and the upper end of the limit rod is coaxially connected to a rotating motor, which is fixed by a bracket, and the bracket is located in the upper layer of the limit slot, and walking mechanisms are symmetrically provided at both ends of the bracket for driving the limit rod to move along the extension direction of the limit slot at the upper layer of the limit slot, and the limit rod extends downward from the limit slot and the length of the extension is less than the depth of the slot hole, and a cross bar is provided outwardly in the horizontal direction at the lower end of the limit rod, and the length of the cross bar is less than 5 cm;

[0015] The control system includes a control terminal, a control chip, and a camera module fixed to the bottom of the platform plate and arranged on one side near the limit slot. The control chip and the camera module are respectively connected to the control terminal for communication. The control chip is also electrically connected to the rotating motor, the walking mechanism, and the air pump.

[0016] After placing the two precast concrete blocks in the middle of one layer along the longitudinal direction of the bridge, the entire auxiliary positioning platform is lifted by the lifting trolley on the mobile formwork and is lowered to the two precast concrete blocks in the middle in alignment with the longitudinal axis of the bridge, and the first partition plate and the second partition plate are located between the spacing holes of the two precast concrete blocks. During the lowering process, the position of the slot hole is observed by the camera module, and a control signal is sent to the control chip through the control terminal to adjust the rotating motor and the walking mechanism so that the limit rod and the cross bar are located in the lateral range of the slot hole and avoid the U-shaped steel bar or the straight steel bar, and the elastic end The elastic airbag is located between the concrete precast block below and the concrete precast block outside. The air pump is then started through the control chip to inflate the elastic airbags on both sides. During the inflation process, an extrusion force is generated in the transverse direction of the bridge, pushing the adjacent concrete precast blocks located on the outside of the platform plate to move close to the web formwork of the box beam, and at the same time pushing the two concrete precast blocks at the bottom in the opposite direction until they collide with the universal wheel set. After the adjustment is completed, a signal is sent to the air pump through the control chip to stop inflation. After the elastic airbag shrinks, the entire auxiliary positioning platform is lifted again by the lifting trolley and moved along the longitudinal direction of the bridge to the next workstation.

[0017] Preferably, the elastic airbag includes a plurality of spherical portions arranged in a matrix along a vertical plane, and adjacent spherical portions are connected by straight portions, and the width of the straight portions is smaller than the diameter of the spherical portions.

[0018] The present invention includes at least the following beneficial effects: the upward self-propelled mobile formwork prestressing construction method of the present invention adopts sand bags and concrete precast blocks as the load form when prestressing the mobile formwork, and according to the cross-sectional shape of the box beam and the different prestressing load clamping ratios, the number of concrete precast blocks is increased by hoisting, and they are evenly arranged and laid in layers along the bridge direction. The concrete precast blocks are arranged into two structures including Class A prestressing blocks and Class B prestressing blocks. The concrete precast blocks themselves are convenient for stacking and standardized prefabrication, and a slot is opened in the middle of the top. U-shaped or straight steel bars are arranged in the slot to facilitate the lifting of the concrete precast blocks. In addition, an auxiliary positioning platform is provided to assist in adjusting the position of the concrete precast blocks on the same layer, which can quickly release the occupation of the equipment used for lifting the concrete precast blocks, greatly improving the efficiency of the prestressing loading construction as a whole.

[0019] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the movable formwork of the present invention when preloading;

[0021] Figure 2A schematic diagram of the distribution of the preload provided by the present invention in the longitudinal direction of the bridge;

[0022] Figure 3 This is a top view of the structure of the Class A pre-pressed block of the present invention;

[0023] Figure 4 This is a side structural diagram of a Class A pre-pressed block of the present invention;

[0024] Figure 5 This is a top view of the structure of the Class B pre-pressed block of the present invention;

[0025] Figure 6 This is a side structural diagram of a Class B pre-pressed block of the present invention;

[0026] Figure 7 Schematic diagram of the structure of the auxiliary positioning platform of the present invention;

[0027] Figure 8 This is a top view of the structure of the limiting rod of the present invention before entering the slot;

[0028] Figure 9 This is a top view of the structure of the limiting rod of the present invention after entering the slot hole to limit the position.

[0029] Figure markings in the specification: 1. Mobile formwork, 2. Class A pre-compression block, 3. Class B pre-compression block, 4. Slot hole, 5. U-shaped steel bar, 6. Straight steel bar, 7. Platform plate, 8. First partition, 9. Push cylinder, 10. Second partition, 11. Universal wheel set, 12. Hook, 13. Elastic airbag, 14. Air inlet, 15. Limit groove, 16. Limit rod, 17. Camera module, 18. Ball part, 19. Straight part, 20. Lifting trolley, 21. Formwork, 22. Sand bag, 23. Cross bar. DETAILED DESCRIPTION

[0030] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0031] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "horizontal", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0032] like Figure 1-9As shown, the present invention provides a construction method for pre-stressing an upward self-propelled mobile formwork, in which pre-stressing is performed on the mobile formwork 1 using a pre-stressing method of precast concrete blocks + sandbags 22. According to the cross-sectional shape of the box beam, an equal load effect is achieved with high beam ends and low mid-span. In the cross-sectional direction of the box beam, the flange plates of the corresponding box beam are pre-stressed using sandbags 22, and the web plates and top and bottom plates of the corresponding box beam are pre-stressed using precast concrete blocks.

[0033] During preloading, the stacking load should try to simulate the stress state during the construction of the box girder. Preloading is carried out by precast concrete blocks + sandbags. After the sandbags are bagged, they are transported to the platform by car and then hoisted onto the bridge by crane. The sandbags are stacked in layers and arranged according to the cross-sectional shape of the box girder to achieve an equal load effect with high beam ends and low mid-span for preloading. By adopting the preloading method of precast concrete blocks, the load conditions during preloading are easier to adjust. At the same time, the precast concrete blocks used as loads can be standardized, which reduces the manufacturing and production costs.

[0034] In another technical solution, Figure 1-7 As shown, the concrete precast blocks include type A precast blocks 2 and type B precast blocks 3. Type A precast blocks 2 and type B precast blocks 3 are both C20 concrete precast blocks and are in the shape of quadrangular prisms.

[0035] Two types of quadrangular prism-shaped preload blocks are designed for counterweighting according to the size of the box girder, which facilitates adjustment and weight combination to ensure that the expected preload load is achieved without the need to frequently adjust the direction of the preload blocks.

[0036] In another technical solution, Figure 1-7 As shown, the bottom side length of the Class A pre-compression block 2 is 120 cm and the height is 75 cm, the bottom side length of the Class B pre-compression block 3 is 120 cm and the height is 30 cm, and a cubic slot 4 with a side length of 20 cm is provided downward at the top center of the Class A pre-compression block 2 and the Class B pre-compression block 3 respectively, and two U-shaped steel bars 5 are arranged downwardly in the slot 4 of the Class A pre-compression block 2, aligned with the center line, and the two U-shaped steel bars 5 are arranged perpendicular to each other in the horizontal plane. The two ends of the U-shaped steel bars 5 are 50 cm long and the middle is 80 cm long. The height difference between the top of the U-shaped steel bar 5 and the top of the slot 4 is 10 cm. Two straight steel bars 6 are arranged in the slot 4 of the Class B pre-compression block 3, aligned with the center line and perpendicular to each other along the horizontal direction. The straight steel bar 6 is 100 cm long and has a height difference of 10 cm with the top of the slot 4.

[0037] By designing the size of the concrete precast blocks, a slot 4 is opened in the middle of each concrete precast block, and then steel bars are arranged to pass through the slot 4 horizontally. Depending on the height of the concrete precast blocks, they are respectively arranged as U-shaped steel bars 5 or straight steel bars 6. On the one hand, the structural strength of the concrete precast blocks is enhanced, and on the other hand, it is convenient for lifting.

[0038] In another technical solution, Figure 1 As shown, the preloading load is divided into three levels according to 60%, 100% and 120% of the maximum construction load. The holding time of the three levels of loading is not less than 2h, 2h and 8h respectively. During the preloading process, the settlement of the movable formwork 1 is observed. When the difference in the observed deformation values ​​is less than 2mm, the deformation is considered stable.

[0039] The cast-in-place process of each box girder is simulated and actual loading is carried out to verify the bearing capacity. Because the load is added sequentially and the observation time (or unloading time) is long, the load is loaded and unloaded in stages. After the staged static time, the elevation value of each measuring point is measured. After each stage of loading is completed, it is necessary to observe once an hour. After each stage of loading is static, the change value of the preload observation point is measured. When the observed deformation is no more than 2mm, it is considered stable. After analysis, loading is continued. After all loading is completed, the load is maintained for 8 hours and the difference between the last two observed deformation values ​​is less than 2mm, the deformation can be considered stable.

[0040] In another technical solution, Figure 1-2 As shown, a 32m box girder is cast in situ on the mobile formwork 1, and the box girder is divided into three areas along the length direction, wherein the first area is symmetrically located at both ends of the box girder and has a length of 1.5m, the second area is symmetrically located on the inner side of the first area and has a length of 3m, and the third area is set between the two second areas. The first area, the second area, and the third area are preloaded with 60%, 100%, and 120% of the maximum construction load respectively.

[0041] Load calculation: The design weight of a 32m box girder is 758.4t. To simulate actual construction conditions, the box girder reinforcement weighs approximately 70.5t, and the actual weight of the box girder is 828.9t. The two ends of the simply supported beam are located directly above the piers. Calculated within a 1.5m range, that is, the first area, the weight is 54.8t (one side), the second area is 3m long, the weight is 89.3t (one side), the third area is 23.6m long, the weight is 270.8t (half), and 830t is taken for preload calculation. The inner formwork of mobile formwork 1 weighs 32t, and various construction loads are approximately 5t (manual load, mechanical load, etc.). Preload load = (beam weight + inner formwork weight + construction load) * 1.2 = (830 + 32 + 5) × 1.2 = 1040.4t.

[0042] In another technical solution, Figure 1 As shown, the weight of each sandbag 22 is set to 1.5t. When the web, top and bottom plates of the corresponding box girder are pre-stressed with precast concrete blocks, the Class A pre-stressed blocks 2 are arranged in priority, and the remaining load is supplemented by the Class B pre-stressed blocks 3. All the Class A pre-stressed blocks 2 and the Class B pre-stressed blocks 3 in each layer are evenly placed and the symmetry axes are aligned along the bridge direction.

[0043] Specifically, based on the weight calculated in the above scheme, the loading scheme is as follows:

[0044] The multiple type A pre-compression blocks 2 and type B pre-compression blocks 3 in each layer are arranged along the longitudinal direction of the bridge.

[0045] In the first area, when preloading with 60% of the maximum construction load, 221.8 sandbags are set on one side of the flange plate, and 3 Class A preloading blocks 2 are evenly preloaded on one side of the web plate. The Class A preloading blocks 2 are arranged in three layers upward, with 1 block on each layer, and 1 Class B prefabricated block is placed on the fourth layer; 4 Class A preloading blocks 2 and 2 Class B preloading blocks 3 are evenly preloaded on one side of the top and bottom plates. The 4 Class A preloading blocks 2 on one side of the top and bottom plates are arranged in 2 rows along the bridge direction, with 2 layers in each row and 1 block on each layer, and 1 Class B preloading block 3 is placed on the top of each row.

[0046] In the first area, when preloading with 100% of the maximum construction load, 223 sandbags are set on one side of the flange plate, 6 Class A preloading blocks 2 are uniformly preloaded on one side of the web plate, 8 Class A preloading blocks 2 and 1 Class B preloading block 3 are uniformly preloaded on one side of the top and bottom plates, and the 6 Class A preloading blocks 2 on one side of the web plate are arranged in 6 layers upward, with 1 block on each layer; the 8 Class A preloading blocks 2 on one side of the top and bottom plates are arranged in 2 rows along the bridge direction, with 4 layers in each row and 1 block on each layer, and 1 Class B preloading block 3 is placed on the 5th layer on one side of the top and bottom plates.

[0047] In the first area, when preloading is performed at 120% of the maximum construction load, 223.5 sandbags are set on one side of the flange plate, 7 Class A preloading blocks 2 and 1 Class B preloading block 3 are uniformly preloaded on one side of the web plate, 10 Class A preloading blocks 2 are uniformly preloaded on one side of the top and bottom plates, 7 Class A preloading blocks 2 on one side of the web plate are arranged in 7 layers upward, and 1 Class B preloading block 3 is placed on the 8th layer; 10 Class A preloading blocks 2 are uniformly preloaded on one side of the top and bottom plates, and are arranged in 2 rows along the bridge direction, with 5 layers in each row and 2 blocks in each layer.

[0048] In the second area, when preloading with 60% of the maximum construction load, 223.5 sandbags are set on one side of the flange plate, 5 Class A preloading blocks 2 and 2 Class B preloading blocks 3 are evenly preloaded on one side of the web plate, 7 Class A preloading blocks 2 and 1 Class B preloading block 3 are evenly preloaded on the top and bottom plates, and the 5 Class A preloading blocks 2 on one side of the web plate are evenly arranged in 2 layers, with 3 blocks in the first layer and 2 blocks in the second layer, and 2 Class B preloading blocks 3 are evenly placed on the third layer; the 7 Class A preloading blocks 2 on the top and bottom plates are arranged in 2 rows along the bridge direction, with 1 layer in each row and 3 blocks in each layer, and the remaining 1 Class A preloading block 2 and 1 Class B preloading block 3 are evenly placed on the second layer of the top and bottom plates.

[0049] In the second area, when preloading at 100% of the maximum construction load, 226 sandbags were placed on one side of the flange plate. The web plate was uniformly preloaded with nine Class A preload blocks 2 and one Class B preload block 3. The top and bottom plates were uniformly preloaded with twelve Class A preload blocks 2 and one Class B preload block 3. The nine Class A preload blocks on one side of the web plate were arranged in two rows of three layers, with three blocks per layer, and one Class B preload block 3 was placed in the third layer. The twelve Class A preload blocks 2 on the top and bottom plates were arranged in two rows along the longitudinal direction of the bridge, with three blocks per row, for two layers. One Class B preload block 3 was placed in the third layer of the top and bottom plates.

[0050] In the second area, when preloading is performed at 120% of the maximum construction load, 227 sandbags are set on one side of the flange plate, 11 Class A preloading blocks 2 are uniformly preloaded on one side of the web plate, and 13 Class A preloading blocks 2 and 1 Class B preloading block 3 are uniformly preloaded on the top and bottom plates; the 11 Class A preloading blocks on one side of the web plate are arranged in 4 layers in 2 rows, with 3 blocks in each layer; the 13 Class A preloading blocks 2 on the top and bottom plates are arranged in 2 columns along the bridge direction, with 3 blocks in each column, for a total of 3 layers, and 1 Class B preloading block 3 is placed in the empty position of the 3rd layer of the top and bottom plates.

[0051] In the third area, when preloading is performed at 60% of the maximum construction load, 2228.2 sandbags are set on one side of the flange plate, 31 Class A preloading blocks 2 are uniformly preloaded on one side of the web plate, and 43 Class A preloading blocks 2 and 1 Class B preloading block 3 are uniformly preloaded on the top and bottom plates; the 31 Class A preloading blocks 2 on one side of the web plate are arranged in 2 layers, with 19 blocks in the first layer; the 43 Class A preloading blocks 2 on the top and bottom plates are arranged in 2 columns along the bridge direction, with 2 layers in each column, 19 blocks in the first layer, and the remaining Class A preloading blocks 2 and 1 Class B preloading block 3 are evenly placed in the second layer.

[0052] In the third area, when preloading with 100% of the maximum construction load, 2247 sandbags are set on one side of the flange plate, 50 Class A preloading blocks 2 and 1 Class B preloading block 3 are uniformly preloaded on one side of the web plate, and 72 Class A preloading blocks 2 are uniformly preloaded on the top and bottom plates; the 50 Class A preloading blocks on one side of the web plate are arranged in 2 rows and 3 layers, with 19 blocks in each layer of the 1st and 2nd layers, and 1 Class B preloading block 3 is placed in the empty position of the 3rd layer on one side of the web plate; the 72 Class A preloading blocks 2 on the top and bottom plates are arranged in 2 columns along the longitudinal direction of the bridge, with 2 layers in each column, 19 blocks in the first layer, and 17 blocks in the second layer.

[0053] In the third area, when preloading is performed at 120% of the maximum construction load, 2,256 sandbags are set on one side of the flange plate, 61 Class A preloading blocks 2 and 3 Class B preloading blocks 3 are evenly preloaded on one side of the web plate, and 87 Class A preloading blocks 2 are evenly preloaded on the top and bottom plates; the 61 Class A preloading blocks 2 on one side of the web plate are arranged in 4 layers, with 19 blocks in each layer, of which the remaining 4 Class A preloading blocks 2 and 3 Class B preloading blocks 3 in the 4th layer are evenly placed; the 87 Class A preloading blocks 2 on the top and bottom plates are arranged in 2 rows along the bridge direction, with 3 layers in each row and 19 blocks in each layer, and the remaining Class A preloading blocks 2 in the 3rd layer are evenly placed.

[0054] In another technical solution, Figure 7-9 As shown, when stacking the Class A pre-compression blocks 2, an auxiliary positioning platform is provided to assist in adjusting the horizontal position of the Class A pre-compression blocks 2 in the transverse direction of the bridge. The auxiliary positioning platform is provided on the Class A pre-compression blocks 2 located in the middle of the top and bottom plates of the corresponding box beams and in the same horizontal plane, and includes:

[0055] The platform plate 7 is a horizontally arranged square structure with a width and length covering at least two of the Class A pre-loaded blocks 2. The bottom surface of the platform plate 7 is a sliding surface. A first partition plate 8 is provided downwardly in the middle of the platform plate 7. A downwardly telescopic pushing cylinder 9 is provided inside the first partition plate 8. The telescopic end of the pushing cylinder 9 is connected to a second partition plate 10. The second partition plate 10 is consistent with the size of the first partition plate 8, and the first partition plate 8 and the second partition plate 10 are respectively provided with a universal wheel set 11 on the left and right sides in the longitudinal direction of the bridge. The thickness of the first partition plate 8 plus the universal wheel sets 11 on both sides in the transverse direction of the bridge is consistent with the setting spacing of the two adjacent Class A pre-loaded blocks 2 in the middle. A hook 12 is provided on the top edge of the platform plate 7;

[0056] Elastic airbags 13 are respectively provided downwardly at both ends of the platform plate 7 in the transverse direction of the bridge. The elastic airbags 13 extend along the longitudinal direction of the bridge and downwardly to the bottom of one of the Class A pre-compression blocks 2. An air inlet 14 communicating with the elastic airbag 13 is provided at the top corner of the platform plate 7 corresponding to the elastic airbag 13. The air inlet 14 is connected to the air pump;

[0057] The limiting assembly is symmetrically provided with four at the bottom of the platform plate 7, including limiting grooves 15 extending along the diagonal direction of the platform plate 7, one limiting groove 15 corresponds to one of the slot holes 4, and the limiting groove 15 is divided into two layers connected in an upper and lower manner, wherein the width of the upper layer is greater than the width of the lower layer, and the lower layer of the limiting groove 15 is slidably connected to a vertically arranged limiting rod 16, and the upper end of the limiting rod 16 is coaxially connected to a rotating motor, which is fixed by a bracket, and the bracket is located in the upper layer of the limiting groove 15, and walking mechanisms are symmetrically provided at both ends of the bracket for driving the limiting rod 16 to move along the extension direction of the limiting groove 15 in the upper layer of the limiting groove 15, and the limiting rod 16 extends downward from the limiting groove 15 and the length of the extension is less than the depth of the slot hole 4, and the lower end of the limiting rod 16 is provided with a cross bar 23 outward in the horizontal direction, and the length of the cross bar 23 is less than 5 cm;

[0058] The control system includes a control terminal, a control chip, and a camera module 17 fixed to the bottom of the platform plate 7 and arranged on one side near the limit groove 15. The control chip and the camera module 17 are respectively connected to the control terminal for communication. The control chip is also electrically connected to the rotating motor, the walking mechanism, and the air pump.

[0059] After placing the two concrete precast blocks in the middle of one layer along the longitudinal direction of the bridge, the entire auxiliary positioning platform is lifted by the lifting trolley 20 on the mobile formwork 1 and is aligned with the longitudinal axis and placed on the two concrete precast blocks in the middle, and the first partition 8 and the second partition 10 are located between the spacing holes of the two concrete precast blocks. During the lowering process, the position of the slot 4 is observed by the camera module 17, and a control signal is sent to the control chip through the control terminal to adjust the rotating motor and the walking mechanism so that the limit rod 16 and the cross bar 23 are located in the lateral range of the slot 4 and avoid the U-shaped steel bar 5 or the straight steel bar 6. The end The elastic airbag 13 is located between the concrete precast block below and the concrete precast block on the outside. The air pump is then started by the control chip to inflate the elastic airbags 13 on both sides. During the inflation process, an extrusion force is generated in the transverse direction of the bridge, pushing the adjacent concrete precast blocks located on the outside of the platform plate 7 to move close to the web formwork 21 of the box beam, and at the same time pushing the two concrete precast blocks at the bottom in the opposite direction until they collide with the universal wheel set 11. After the adjustment is completed, a signal is sent to the air pump through the control chip to stop inflation. After the elastic airbag 13 shrinks, the entire auxiliary positioning platform is lifted again by the lifting trolley 20 and moved along the longitudinal direction of the bridge to the next workstation.

[0060] After placing a layer of Class A pre-stressed blocks 2, the lateral positions of the adjacent Class A pre-stressed blocks 2 or Class B pre-stressed blocks 3 in the horizontal direction are adjusted through the auxiliary positioning platform, which can more quickly remove the restrictions on the lifting equipment of the concrete precast blocks and reduce the adjustment requirements for the concrete precast blocks. In particular, for high-altitude construction, the problem of inconvenient adjustment of the lifting equipment is solved, and the overall lifting efficiency of the pre-stressed load material is improved. The elastic airbag 13 is arranged along the vertical plane and extends along the longitudinal direction of the bridge. A sealing ring and other materials can be provided at the air inlet 14 to facilitate the sealing of the air inlet channel. Air is ventilated into the elastic airbag 13, and the elastic airbag 13 expands until it contacts the concrete precast blocks on the left and right sides (Class A pre-stressed blocks 2 or Class B pre-stressed blocks 3) and begins to generate a transverse squeezing force on the concrete precast blocks, forming a thrust. When the weight of the concrete precast blocks at the bottom of the platform plate 7, the pressure of the platform plate 7 and the equipment on the platform plate 7 are sufficient, the airbag located on the outside of the platform plate 7 is as Figure 4 The two Class A pre-stressed blocks 2 on the outer sides in the left and right directions are pushed and approach the web formwork 21 to the required position. After the thrust is greater and the Class A pre-stressed blocks 2 at the web are pushed to the required position, the elastic airbag 13 may play a certain lifting role on the platform plate 7 as a whole to offset part of the gravity of the platform plate 7, so as to facilitate the pushing of the two Class A pre-stressed blocks 2 located at the bottom of the platform plate 7. The two Class A pre-stressed blocks 2 are pushed to the closest point, that is, they collide with each other on the universal wheel group 11 of the first partition 8. As the number of layers of concrete precast blocks increases, the set pushing cylinder 9 can extend downward from the second partition 10 to between the two adjusted Class A pre-stressed blocks 2 on the lower layer, further improving the directional linearity of the concrete precast blocks pushed by the elastic airbag 13. Due to the set universal wheel group 11, the platform plate 7 is easy to move along the bridge direction, or to facilitate the downward movement of the second partition 10. The set limit assembly and the limit groove 15 have a certain length, which makes it possible to make it possible to move to a certain extent. The limit rod 16 can adapt to the size of the slot 4 and the position of the Class A pre-loaded block 2. When the slot 4 of the Class A pre-loaded block 2 at the bottom of the platform plate 7 is not completely aligned, the bottom image is obtained by the camera module 17 and transmitted to the control terminal. Then, the walking mechanism, such as the walking wheel with a drive motor, only needs to meet the moving function and be adjusted. The limit rod 16 can move along the diagonal line of the platform plate 7 as a whole, and according to the position of the U-shaped steel bar 5 or the straight steel bar 6, drive the rotating motor to rotate slightly so that the cross bar 23 can avoid it. The cross bar 23 is set to a size slightly smaller than 5 cm. After the limit rod 16 completely enters the slot 4, it cooperates with the adjustment of the rotating motor and the walking mechanism to make the cross bar 23 located below the middle of the U-shaped steel bar 5 or the straight steel bar 6. Therefore, when the platform plate 7 may be subjected to the lifting force of the elastic airbag 13, it will contact the cross bar 23 from the bottom of the U-shaped steel bar 5 or the straight steel bar 6 to limit it. Of course, a camera component can also be set on the mobile formwork 1 for real-time observation.

[0061] In another technical solution, Figure 7As shown, the elastic airbag 13 includes multiple spherical portions 18 arranged in a matrix along a vertical plane. Adjacent spherical portions 18 are connected by straight portions 19, the width of which is smaller than the diameter of the spherical portions 18. The combination of spherical portions 18 and straight portions 19 facilitates control of the volume and direction of expansion while also increasing the contact area between the elastic airbag 13 and the precast concrete block.

[0062] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for pre-pressing a self-propelled upward movable formwork, characterized in that: Pre-compression is carried out on the mobile formwork using a combination of precast concrete blocks and sandbags. Based on the cross-sectional shape of the box girder, the pre-compression is arranged to create an equal load effect with the beam ends being higher and the spans being lower. In the cross-sectional direction of the box girder, the flange plates of the corresponding box girder are pre-compressed with sandbags, while the webs, top and bottom plates of the box girder are pre-compressed with precast concrete blocks. The concrete precast blocks include Class A precast blocks and Class B precast blocks, both of which are C20 concrete precast blocks and are in the shape of quadrangular prisms. When stacking the Class A pre-compression blocks, an auxiliary positioning platform is provided to assist in adjusting the horizontal position of the Class A pre-compression blocks in the transverse direction of the bridge. The auxiliary positioning platform is provided on the Class A pre-compression blocks located in the middle of the top and bottom plates of the corresponding box beams and in the same horizontal plane, and includes: The platform plate is a horizontally arranged square structure with a width and length covering at least two of the Class A pre-loaded blocks. The bottom surface of the platform plate is a sliding surface. A first partition is provided downwardly in the middle of the platform plate. A downwardly telescopic pushing cylinder is provided inside the first partition. The telescopic end of the pushing cylinder is connected to a second partition. The second partition is consistent in size with the first partition, and the first and second partitions are respectively provided with universal wheel sets on the left and right sides in the longitudinal direction of the bridge. The thickness of the first partition plus the universal wheel sets on both sides in the transverse direction of the bridge is consistent with the setting spacing of the two adjacent Class A pre-loaded blocks in the middle. A hook is provided on the edge of the top surface of the platform plate. The elastic airbag is arranged downward at both ends of the platform plate in the transverse direction of the bridge. The elastic airbag extends along the longitudinal direction of the bridge and downward to the bottom of a Class A pre-loaded block. An air inlet connected to the elastic airbag is provided at the top corner of the platform plate corresponding to the elastic airbag, and the air inlet is connected to the inflation pump.

2. The upward self-propelled movable formwork pre-pressing construction method according to claim 1, characterized in that: The bottom side length of the Class A pre-compression block is 120 cm and the height is 75 cm. The bottom side length of the Class B pre-compression block is 120 cm and the height is 30 cm. A cubic slot with a side length of 20 cm is provided downward at the top center of the Class A pre-compression block and the Class B pre-compression block. Two U-shaped steel bars are arranged downward in the slot of the Class A pre-compression block, aligned with the center line. The two U-shaped steel bars are arranged perpendicular to each other in the horizontal plane. The two ends of the U-shaped steel bars are 50 cm long and the middle is 80 cm long. The height difference between the top of the U-shaped steel bar and the top of the slot is 10 cm. Two straight steel bars are arranged in the slot of the Class B pre-compression block, aligned with the center line and perpendicular to each other along the horizontal direction. The straight steel bars are 100 cm long and have a height difference of 10 cm with the top of the slot.

3. The upward self-propelled movable formwork pre-pressing construction method according to claim 2, characterized in that: The preloading load is divided into three levels according to 60%, 100% and 120% of the maximum construction load. The holding time of the three levels of loading is not less than 2h, 2h and 8h respectively. During the preloading process, the settlement of the movable formwork is observed. When the difference between the observed deformation values ​​is less than 2mm, the deformation is considered stable.

4. The upward self-propelled movable formwork pre-pressing construction method according to claim 3, characterized in that: A 32m box girder was cast in situ on the movable formwork, and the box girder was divided into three areas along the length direction, wherein the first area was symmetrically located at both ends of the box girder and had a length of 1.5m, the second area was symmetrically located on the inner side of the first area and had a length of 3m, and the third area was set between the two second areas. The first area, the second area, and the third area were preloaded with 60%, 100%, and 120% of the maximum construction load respectively.

5. The upward self-propelled movable formwork pre-pressing construction method according to claim 4, characterized in that: The weight of each sandbag is set to 1.5t. When the web, top and bottom plates of the corresponding box girder are pre-stressed with precast concrete blocks, the Class A pre-stressed blocks are arranged in priority, and the remaining load is supplemented by the Class B pre-stressed blocks. All the Class A pre-stressed blocks and the Class B pre-stressed blocks in each layer are evenly placed and their symmetry axes are aligned along the bridge direction.

6. The upward self-propelled movable formwork pre-pressing construction method according to claim 5, characterized in that: The auxiliary positioning platform also includes: The limit assembly is symmetrically provided with four at the bottom of the platform plate, including limit slots extending along the diagonal direction of the platform plate, one limit slot corresponds to one of the slot holes, and the limit slot is divided into two layers connected to each other, wherein the width of the upper layer is greater than the width of the lower layer, and the lower layer of the limit slot is slidably connected to a vertically arranged limit rod, and the upper end of the limit rod is coaxially connected to a rotating motor, which is fixed by a bracket, and the bracket is located in the upper layer of the limit slot, and walking mechanisms are symmetrically provided at both ends of the bracket for driving the limit rod to move along the extension direction of the limit slot at the upper layer of the limit slot, and the limit rod extends downward from the limit slot and the length of the extension is less than the depth of the slot hole, and a cross bar is provided outwardly in the horizontal direction at the lower end of the limit rod, and the length of the cross bar is less than 5 cm; The control system includes a control terminal, a control chip, and a camera module fixed to the bottom of the platform plate and arranged on one side near the limit slot. The control chip and the camera module are respectively connected to the control terminal for communication. The control chip is also electrically connected to the rotating motor, the walking mechanism, and the air pump. After placing the two precast concrete blocks in the middle of one layer along the longitudinal direction of the bridge, the entire auxiliary positioning platform is lifted by the lifting trolley on the mobile formwork and is lowered to the two precast concrete blocks in the middle in alignment with the longitudinal axis of the bridge, and the first partition plate and the second partition plate are located between the spacing holes of the two precast concrete blocks. During the lowering process, the position of the slot hole is observed by the camera module, and a control signal is sent to the control chip through the control terminal to adjust the rotating motor and the walking mechanism so that the limit rod and the cross bar are located in the lateral range of the slot hole and avoid the U-shaped steel bar or the straight steel bar, and the elastic end The elastic airbag is located between the concrete precast block below and the concrete precast block outside. The air pump is then started through the control chip to inflate the elastic airbags on both sides. During the inflation process, an extrusion force is generated in the transverse direction of the bridge, pushing the adjacent concrete precast blocks located on the outside of the platform plate to move close to the web formwork of the box beam, and at the same time pushing the two concrete precast blocks at the bottom in the opposite direction until they collide with the universal wheel set. After the adjustment is completed, a signal is sent to the air pump through the control chip to stop inflation. After the elastic airbag shrinks, the entire auxiliary positioning platform is lifted again by the lifting trolley and moved along the longitudinal direction of the bridge to the next workstation.

7. The upward self-propelled movable formwork pre-pressing construction method according to claim 6, characterized in that: The elastic airbag comprises a plurality of ball parts arranged in a matrix along a vertical plane, and adjacent ball parts are connected by straight parts, wherein the width of the straight parts is smaller than the diameter of the ball parts.

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