Steel box girder falling beam construction device and falling beam construction method

Abstract

A steel box girder falling beam construction device comprises the following steps: S1, installing the support at the top of all the piers first, and then installing the steel box girder construction device; S2, lifting the steel box girder by synchronously jacking all the hydraulic jacks one, and lifting the hydraulic jacks two; S3, removing the steel pad plate and the high block under all the hydraulic jacks two; S4, synchronously extending all the hydraulic jacks two to support the steel box girder, and synchronously returning all the hydraulic jacks one to the initial state; S5, removing the steel pad plate and the high block under all the hydraulic jacks; S6, returning the hydraulic jacks two to the initial state, and lowering the steel box girder by one steel pad plate and one high block; S7, repeating the steps S2-S6 in sequence until the steel box girder falls on the support, and then fixing the support and the steel box girder, and removing the hydraulic jacks one and two and the remaining high blocks and steel pad plates.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel box girder construction, in particular to a steel box girder falling beam construction device and a falling beam construction method. BACKGROUND

[0002] Steel box girder is a common structure form of large-span bridge, which is often used in crossing existing railway, high-value bridge and other construction. The steel box girder construction operation mode mainly includes two types: (1) for small-span and small-specification steel box girder, a crane is used for hoisting and installing; (2) for large-span and large-specification steel box girder, the hoisting risk is high, and a pushing + falling beam mode is used for installing, that is, a longitudinal bridge sliding rail is installed on the pier column, the steel box girder is pushed to the pier column from one side, and then the hydraulic top is used for gradually falling the beam, the support is installed after the beam is fallen, and finally the steel box girder is installed on the support. The existing two construction methods can meet the installation requirements of most steel box girders. Since the conventional falling beam height is 2 meters or more, when a super-large-span and super-large-specification steel box girder appears, and the falling beam height exceeds the maximum falling beam height (such as 2.9 meters), after the steel box girder is pushed and installed, the falling beam construction is extremely difficult, for example, the support volume of such a super-large steel box girder is large, and the installation of the support after the beam is fallen consumes a lot of manpower, material resources and time, and a construction method for super-large steel box girder under the condition of large falling beam height needs to be developed.

[0003] In addition, in the existing falling beam construction process, most of the steel structure welding height blocks are used for the falling beam construction of super-large steel box girders. If the steel structure is used, a large amount of steel is consumed, and the installation and disassembly are extremely difficult. In the falling beam construction process, the steel cannot be used after cutting. SUMMARY

[0004] In order to solve the problems of the prior art, the present application provides a steel box girder falling beam construction device and a falling beam construction method, a steel and concrete combined height block is developed, the amount of steel investment is reduced, the support is pre-installed on the pier top before the height block is installed, and the falling beam construction is implemented in combination with the structure of the steel-concrete height block, the construction efficiency is improved, and the consumption of manpower, material resources and time can be greatly saved.

[0005] The utility model provides a kind of steel box girder falls beam with supporting device, including several rectangular first heightening blocks and several second heightening blocks in the form of '' concave '', the first heightening block includes the channel steel frame of periphery and the internal cast reinforced concrete slab, two first cushion layers are detachably fixed and installed to the side edge of the first heightening block;Second cushion layer is detachably fixed and installed to the side edge of the second heightening block, and the internal rectangular cavity of the second cushion layer is formed;Several first cushion layers are vertically stacked, and several second cushion layers are vertically stacked, steel pad is padded between adjacent upper and lower heightening blocks, and the upper end surface of the second cushion layer in the uppermost end is padded with two support plates, and the first cushion layer is stacked on the support plate.

[0006] Preferably, one side edge channel steel of the first heightening block extends outward to form a first connecting rod, through holes are processed at both ends of the first connecting rod, and the first connecting rods of the two first heightening blocks are fixedly connected by bolts and nuts after butt joint to form the first cushion layer.

[0007] Preferably, the butt joint side edge channel steel of the second heightening block extends outward to form a second connecting rod, through holes are processed at both ends of the second connecting rod, and the second connecting rods of the two second heightening blocks are fixedly connected by bolts and nuts after butt joint to form the second cushion layer.

[0008] Preferably, two lifting holes are respectively processed at the positions of four corners of the first heightening block, and two lifting holes are respectively processed at the positions of dead corners of the second heightening block.

[0009] Preferably, the cavity in the second cushion layer is a support cavity for placing a support.

[0010] A steel box girder falling beam construction device is provided, two supports are fixedly installed at the top of each pier column, two supporting devices are respectively buckled on the two supports, the supports are located in the support cavities, and the first connecting rod and the second connecting rod in the supporting device are arranged in the transverse bridge direction, two vertical hydraulic jacks are respectively placed on the two uppermost heightening blocks after laying a layer of steel pad plate on the uppermost heightening block, the two hydraulic jacks are distributed in the longitudinal bridge direction and are hydraulic jack one and hydraulic jack two respectively, the shaft end of the hydraulic jack is fixedly installed at the bottom of the steel box girder that is being pulled and positioned and waiting for the falling beam, two groups of supporting devices are provided on each pier top, two jacks are placed on each supporting device, and the pier column-supporting device-hydraulic jack forms a supporting system for supporting the steel box girder from bottom to top;Three transverse bridge tracks are welded on the bottom of the steel box girder corresponding to the supporting device, the three tracks correspond to the two sides of the supporting device and the connecting rod position respectively, a pulley is installed in the track, and an inverted chain hook is installed on the shaft of the pulley.

[0011] A steel box girder falling beam construction method is provided, comprising the following steps:

[0012] S1, pre-installing the support at the top of all piers, then installing the steel box girder construction device, the hydraulic jack one and the hydraulic jack two are in the initial state of retraction;

[0013] S2, synchronously jacking up all the hydraulic jack one, lifting the steel box girder, the hydraulic jack two is lifted;

[0014] S3: removing the steel pad plate and the layer of high blocks below all the hydraulic jack two;

[0015] S4: synchronously extending all the hydraulic jack two to support state, synchronously returning all the hydraulic jack one to the initial state;

[0016] S5: removing the steel pad plate and the layer of high blocks below all the hydraulic jack one;

[0017] S6: returning the hydraulic jack two to the initial state, lowering the steel box girder by one steel pad plate + one high block;

[0018] S7: repeating the steps of S2-S6 in turn until the steel box girder is lowered on the support, then fixing the support and the steel box girder, removing the hydraulic jack one and the hydraulic jack two and the remaining high blocks and steel pad plates.

[0019] Preferably, in the step S1, two supports are pre-installed on each pier, then the lifting support device is buckled on the supports, the shaft end of the hydraulic jack one and the hydraulic jack two is fixedly installed at the bottom of the steel box girder, and the track and the chain hoist are installed.

[0020] Preferably, in the step S1, the pre-installation of the support is specifically that: the support pad is poured on the pier top, the support wheel contour is marked on the pad, and the leveling sand is laid on the pad.

[0021] Preferably, in the step S3, the chain hoist on the track is slid above the high block to be removed, the hook of the hoist is lowered to hook the lifting holes around the high block to lift up, the high block and the steel pad plate are transported outward along the track away from below the hydraulic jack two, then the removed high block and the steel pad plate are lifted by the crane, the chain hoist is loosened, and the crane adjusts the high block and the steel pad plate away from the construction area.

[0022] Preferably, in the step S5, the chain hoist on the track is slid above the high block to be removed, the hook of the hoist is lowered to hook the lifting holes around the high block to lift up, the high block and the steel pad plate are transported outward along the track away from below the hydraulic jack one, then the removed high block and the steel pad plate are lifted by the crane, the chain hoist is loosened, and the crane adjusts the high block and the steel pad plate away from the construction area.

[0023] Preferably, in the step S7, the fixed connection mode of the support pre-steel box girder is that the installation support bolt is fixed on the pier top, the upper plate of the support is tightly attached to the bottom of the steel box girder, the support grouting material is poured, after the design strength is reached, the jack is unloaded and returns oil, and the hydraulic jack one and the hydraulic jack two and the remaining heightening blocks and the steel backing plate are removed.

[0024] The advantages of the present application include: (1) by designing the structure and connection relationship of the heightening block, a support device is made, a support cavity is designed inside the support device to accommodate the support, the support is placed in advance on the pier top and protected by the support device, the heightening block adopts a channel steel structure frame type reinforced concrete precast block, the precast precision is higher, in order to increase the integrity of the heightening block, the steel backing plate is added between each layer of heightening block, and the two horizontal heightening blocks are connected by bolts and can be detached, in the beam lowering construction process, the support does not need to be hoisted again, and the beam lowering construction process is continuous.(2) The pre-installed support can effectively reduce the high-altitude operation time of personnel, effectively reduce the investment of mechanical equipment, the quality is easy to control, the construction speed is fast, and the work efficiency is high.(3) Compared with the traditional steel structure, the heightening block of the steel-concrete structure can greatly save the consumption of steel. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a top view structural schematic diagram of the first heightening block of the embodiment 1 of the present application.

[0026] Figure 2 is a top view structural schematic diagram of the first heightening block of the embodiment 1 of the present application.

[0027] Figure 3 is a top view structural schematic diagram of the first backing layer of the embodiment 1 of the present application.

[0028] Figure 4 is a top view structural schematic diagram of the second backing layer of the embodiment 1 of the present application.

[0029] Figure 5 is a front view structural schematic diagram of the support device for the steel box girder beam lowering of the embodiment 1 of the present application.

[0030] Figure 6 is a side view structural schematic diagram of the support device for the steel box girder beam lowering of the embodiment 1 of the present application.

[0031] Figure 7 is a front view structural schematic diagram of the steel box girder beam lowering construction device of the embodiment 2 of the present application.

[0032] Figure 8 is a side view structural schematic diagram of the steel box girder beam lowering construction device of the embodiment 2 of the present application.

[0033] Figure 9 is a structural schematic diagram (a) of the step S1 of the steel box girder beam lowering construction method of the embodiment 2 of the present application.

[0034] Figure 10 is a structural schematic diagram (b) of steps S2-S3 of the steel box girder launching construction method of the embodiment 2 of the present application.

[0035] Figure 11 is a structural schematic diagram (c) of step S4 of the steel box girder launching construction method of the embodiment 2 of the present application.

[0036] Figure 12 is a structural schematic diagram (d) of step S5 of the steel box girder launching construction method of the embodiment 2 of the present application.

[0037] Figure 13 is a structural schematic diagram (e) of step S6 of the steel box girder launching construction method of the embodiment 2 of the present application.

[0038] Figure 14 is a structural schematic diagram (f) of the heightening block dismounting and transporting in the steel box girder launching construction method of the embodiment 2 of the present application.

[0039] Wherein, the same components in the drawings are marked with the same reference numerals; the drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0040] The present application will be further described below in conjunction with the drawings and embodiments.

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative work fall within the protection scope of the present application.

[0042] Embodiment 1

[0043] The present application provides a steel box girder launching construction device and a launching construction method. A heightening block combined with steel and concrete is developed to reduce the amount of steel input. The support is pre-installed on the pier top before the installation of the heightening block. The launching construction is implemented by combining the structure of the steel-concrete heightening block, which improves the construction efficiency and greatly saves the consumption of manpower, material resources, time and other costs.

[0044] The utility model provides a kind of steel box girder falls beam and uses supporting device, including several rectangular first heightening block 1 and several "concave" second heightening block 2, the first heightening block 1 includes the channel steel frame of periphery and internal cast reinforced concrete slab, two first cushion layer of the first heightening block 1 side edge detachably fixed installation;Second cushion layer is formed to rectangular cavity 3 in the second heightening block 2 including periphery's channel steel frame and internal cast reinforced concrete slab, two second heightening block 2 side edge detachably fixed installation;Several first cushion layer is vertically stacked, several second cushion layer is vertically stacked, and steel pad 4 is padded between adjacent upper and lower heightening block, the upper end surface of the second cushion layer in the uppermost end is padded with two support plates 5, and the first cushion layer is stacked on the support plate 5.The first connecting rod 6 is formed by extending outward from one side edge channel steel of the first heightening block 1, and through holes are processed at both ends of the first connecting rod 6, and the first connecting rod 6 of two first heightening blocks 1 is connected by bolt and nut after butt joint to form the first cushion layer.The second connecting rod 7 is formed by extending outward from butt joint side edge channel steel of the second heightening block 2, and through holes are processed at both ends of the second connecting rod 7, and the second connecting rod 7 of two second heightening blocks 2 is connected by bolt and nut after butt joint to form the second cushion layer.Two lifting holes 8 are respectively processed at the position of four corners of the first heightening block 1, and two lifting holes 8 are respectively processed at the position of dead angle of the second heightening block 2.The cavity in the second cushion layer is support cavity 9 for placing support.

[0045] Embodiment 2

[0046] A kind of steel box girder falls beam construction device, two supports 10 are fixedly installed at the top of each pier 14, two supporting devices are respectively buckled on two supports 10, support 10 is located in support cavity 9, and first connecting rod 6 and second connecting rod 7 are arranged in horizontal bridge direction in supporting device, after laying a layer of steel pad 4 on the uppermost end heightening block, two vertical hydraulic jacks are respectively placed on the uppermost end two heightening blocks, two hydraulic jacks are distributed along longitudinal bridge, are hydraulic jack one 11 and hydraulic jack two 12 respectively, the shaft end of hydraulic jack is fixedly installed at the bottom of steel box girder 13 that is pulled in position and waits for beam drop, two groups of supporting devices are provided on each pier top, two jacks are placed on each supporting device, pier 14-supporting device-hydraulic jack forms the support system of supporting steel box girder 13 from bottom to top;Three horizontal bridge tracks 15 are welded on the bottom of corresponding steel box girder 13 of supporting device, three tracks 15 correspond to the two sides of supporting device and connecting rod position respectively, pulley is installed in track 15, and inverted chain hook 16 is installed on the shaft of pulley.

[0047] A kind of steel box girder falls beam construction method, comprising the following steps:

[0048] S1. First, two supports 10 are pre-installed on each pier 14. Then, the hoisting support device is fastened to the support 10. The shaft ends of hydraulic jack 11 and hydraulic jack 2 12 are fixedly installed at the bottom of the steel box girder 13. The track 15 and chain hoist hook 16 are installed. Hydraulic jack 11 and hydraulic jack 2 12 are in the initial retracted state.

[0049] The pre-installation of the support 10 specifically involves: pouring a support pad stone on the top of the pier, marking the outline of the support 10 wheel on the pad stone and laying leveling sand, and placing the support 10 on the sand.

[0050] S2. All hydraulic jacks 11 lift simultaneously, raising the steel box girder 13, and hydraulic jack 2 12 is also lifted.

[0051] S3: Remove all the steel pads 4 and lifting blocks under the hydraulic jacks 2 12: Slide the chain hoist 16 on the track 15 to the top of the lifting block to be removed, lower the hook and hook it to the lifting holes 8 around the lifting block to lift it up, transport the lifting block and steel pads 4 along the track 15 away from the bottom of the hydraulic jacks 2 12, and then use a crane to lift the removed lifting blocks and steel pads 4. After that, release the chain hoist 16 and the crane will move the lifting blocks and steel pads 4 away from the construction area.

[0052] S4: All hydraulic jacks 212 extend synchronously downwards to support the load, and all hydraulic jacks 11 retract synchronously back to their initial state.

[0053] S5: Remove all the steel pads 4 and lifting blocks below the hydraulic jacks 11: Slide the chain hoist 16 on the track 15 to the top of the lifting block to be removed, lower the hook to hook the lifting holes 8 around the lifting block and lift it up. Transport the lifting block and steel pads 4 away from the bottom of the hydraulic jacks 11 along the track 15. Then use a crane to lift the removed lifting blocks and steel pads 4 and release the chain hoist 16. The crane will then move the lifting blocks and steel pads 4 away from the construction area.

[0054] S6: Hydraulic jack 212 returns oil to its initial state, lowering the steel box girder 13 by the height of one steel pad 4 + one heightening block;

[0055] S7: Repeat steps S2-S6 in sequence until the steel box girder 13 is placed on the support 10. After fixing the support 10 to the steel box girder 13, remove the hydraulic jack 11 and hydraulic jack 2 12, as well as the remaining heightening block and steel pad 4.

[0056] The fixed connection mode of the support 10 pre-steel box girder 13 is that the support 10 bolt is fixed on the pier top, the upper plate of the support 10 is tightly attached to the bottom of the steel box girder 13, the support 10 grouting material is poured, after the design strength is reached, the jack is unloaded and returns oil, and the hydraulic jack I 11 and the hydraulic jack II 12 and the remaining heightening block and the steel backing plate 4 are removed.

[0057] The advantages of the present application include: (1) by designing the structure and connection relationship of the heightening block, a support device is made, a support 10 cavity 9 is designed inside the support device to accommodate the support 10, the support 10 is placed in advance on the pier top and protected by the support device, the heightening block adopts a channel steel structure frame type reinforced concrete prefabricated block, the prefabrication precision is higher, in order to increase the integrity of the heightening block, a steel backing plate 4 is added between each layer of heightening block, and the two horizontal heightening blocks are connected by bolts which can be detached, and during the beam falling construction process, the support 10 does not need to be hoisted again, and the beam falling construction process is continuous. (2) The pre-installed support 10 can effectively reduce the high-altitude operation time of personnel, effectively reduce the investment of mechanical equipment, the quality is easy to control, the construction speed is fast, and the work efficiency is high. (3) Compared with the traditional steel structure, the heightening block of the steel-concrete structure can greatly save the consumption of steel.

[0058] Example 3

[0059] The technical scheme of the present application is applied to the ZJTLSG-1 standard crossing Beijing-Shanghai high-speed rail bridge (50+85+50) m steel box continuous beam special construction scheme of Zheng-Ji railway, the steel box girder 13 beam falling height is as high as 2.9 meters, needs to be fallen in multiple times, needs to be constructed on the operating line, the safety pressure is large, the beam falling construction adopts the pre-installed support 10+steel-concrete heightening block+steel backing plate 4 cooperated with the hydraulic jack to fall the beam layer by layer and alternately, and in the actual application, significant economic benefits are obtained:

[0060] In the traditional beam falling construction process, most of the heightening blocks adopt pure steel structure, the beam falling construction of the present project is as high as 2.9 m, if the steel structure type is adopted, a large amount of steel is consumed, and the steel cannot be used after being cut in the beam falling construction process. Therefore, the steel-concrete combined heightening block designed independently in the present project adopts a [14 channel steel structure frame type C50 reinforced concrete prefabricated block, ensures the size precision in the prefabrication process, solves the problem of difficult installation and removal of the heightening block. Compared with the traditional steel structure, the present project saves about 38 tons of steel, shortens the installation and removal construction period of the heightening block by about 16 days. After the steel is used as waste, the loss cost of the steel is about 4500 yuan / t, the steel consumption cost is saved by about 4500*38=171000 yuan, and a total of 171,000 yuan of direct economic benefits is brought.

[0061] The structures, proportions, sizes, etc. shown in the drawings attached to the present specification are merely used to cooperate with the content disclosed in the present specification, to be understood and read by those skilled in the art, and are not used to limit the defined conditions under which the present application can be implemented, and therefore do not have technical substantive significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that can be produced by the present application and the purposes that can be achieved, should still fall within the scope of the technical content disclosed by the present application. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" etc. cited in the present specification are merely for the convenience of clear description, and are not used to limit the scope in which the present application can be implemented, and the change or adjustment of the relative relationship, without substantially changing the technical content, is also regarded as the scope in which the present application can be implemented.

[0062] The present application has been described above with reference to the preferred embodiments, but the scope of protection of the present application is not limited thereto, and all technical solutions falling within the scope of the claims are within the scope of protection of the present application. Various improvements can be made and equivalent parts can be replaced without departing from the scope of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way.

Claims

1. A steel box girder launching construction method, characterized by, The method comprises the following steps: S1, pre-installing the support (10) on the top of all piers (14) and then installing the steel box girder (13) construction device, the hydraulic jack one (11) and the hydraulic jack two (12) are in the initial state of retraction, two supports (10) are pre-installed on each pier (14), and the hoisting support device is buckled on the support (10); the shaft end of the hydraulic jack one (11) and the hydraulic jack two (12) is fixedly installed at the bottom of the steel box girder (13), and the bottom of the hydraulic jack one (11) and the hydraulic jack two (12) is respectively arranged at the top of the two support devices; each support device is composed of multiple layers of high blocks; the multiple layers of high blocks can be sequentially removed from top to bottom through detachable connection between two horizontal high blocks; S2, all hydraulic jack one (11) is synchronously jacked up to lift the steel box girder (13), and the hydraulic jack two (12) is lifted; S3, remove a layer of steel pad (4) and a layer of high block below all hydraulic jack two (12); S4, all hydraulic jack two (12) is synchronously extended to support downward to the support state, and all hydraulic jack one (11) is synchronously returned to the initial state; S5, remove a layer of steel pad (4) and a layer of high block below all hydraulic jack one (11); S6, the hydraulic jack two (12) is returned to the initial state, and the steel box girder (13) is lowered by one steel pad (4) + one high block; S7, sequentially repeat the steps S2-S6 until the steel box girder (13) is lowered on the support (10), after the support (10) and the steel box girder (13) are fixedly connected, the hydraulic jack one (11) and the hydraulic jack two (12) and the remaining high blocks and steel pads (4) are removed.

2. The steel box girder launching construction method according to claim 1, characterized in that, In the step S1, the bottom of the steel box girder (13) is provided with a mounting rail (15) and an inverted chain hook (16).

3. The steel box girder launching construction method according to claim 2, characterized in that, In the step S1, the pre-installation of the support (10) is specifically that a support pad is poured on the top of the pier, the outline of the support (10) is marked on the pad and leveling sand is laid on the pad, and the support (10) is placed on the sand.

4. The steel box girder beam dropping construction method according to claim 1, characterized in that, In the step S3, the inverted chain hook (16) on the rail (15) is slid above the high block to be removed, the hook is lowered to hook the lifting holes (8) around the high block to lift up, the high block and the steel pad (4) are transported outward away from below the hydraulic jack two (12) along the rail (15), then the removed high block and steel pad (4) are lifted by using a crane, the inverted chain hook (16) is loosened, and the crane adjusts the high block and the steel pad (4) away from the construction area.

5. The steel box girder beam dropping construction method according to claim 1, characterized in that, In the step S5, the inverted chain hook (16) on the rail (15) is slid above the high block to be removed, the hook is lowered to hook the lifting holes (8) around the high block to lift up, the high block and the steel pad (4) are transported outward away from below the hydraulic jack one (11) along the rail (15), then the removed high block and steel pad (4) are lifted by using a crane, the inverted chain hook (16) is loosened, and the crane adjusts the high block and the steel pad (4) away from the construction area.

6. The steel box girder beam dropping construction method according to claim 1, characterized in that, In step S7, the fixed connection mode of the support (10) pre-steel box girder (13) is: installing support (10) bolt and pier top fixed, the upper plate of support (10) is close to the bottom of steel box girder (13), pouring support (10) grouting material, after reaching the design strength, jack unloading oil, remove hydraulic jack one (11) and hydraulic jack two (12) and the remaining heightening block and steel backing plate (4).

7. A steel box girder launching device, characterized by, Two supports (10) are fixedly installed on the top of each pier column (14), two support devices are buckled on the two supports (10) respectively, the support (10) is located in the support cavity (9), and the first connecting rod (6) and the second connecting rod (7) in the support device are arranged in a transverse bridge direction, a layer of steel backing plate (4) is laid on the uppermost heightening block, two vertical hydraulic jacks are respectively placed on the uppermost two heightening blocks, the two hydraulic jacks are distributed in a longitudinal bridge direction and are hydraulic jack one (11) and hydraulic jack two (12) respectively, the shaft end of the hydraulic jack is fixedly installed on the bottom of the steel box girder (13) which is pulled into position and waits for the girder to fall, two groups of support devices are arranged on each pier top, two jacks are placed on each support device, and the pier column (14)-support device-hydraulic jack forms a support system for supporting the steel box girder (13) from bottom to top; the support device comprises a plurality of rectangular first heightening blocks and a plurality of "concave" second heightening blocks, the first heightening block comprises a peripheral channel steel frame and an internally poured reinforced concrete plate, and two first heightening blocks are fixedly installed in a detachable manner as a first backing layer; the second heightening block comprises a peripheral channel steel frame and an internally poured reinforced concrete plate, and the side edges of two second heightening blocks are fixedly installed in a detachable manner as a second backing layer, and a rectangular cavity is formed in the interior of the second backing layer; a plurality of first backing layers are vertically stacked, a plurality of second backing layers are vertically stacked, a steel backing plate is arranged between adjacent upper and lower heightening blocks, two support plates are arranged on the upper end face of the uppermost second backing layer, and the first backing layers are stacked on the support plates; three transverse bridge direction rails (15) are welded on the bottom of the corresponding steel box girder (13) of the support device, the three rails (15) correspond to the two sides and the connecting rod positions of the support device respectively, pulleys are installed in the rails (15), and inverted chain hooks (16) are installed on the shafts of the pulleys; when all hydraulic jacks one (11) are synchronously jacked up, the steel box girder (13) is lifted, and the hydraulic jacks two (12) are lifted; at this time, all the steel backing plates (4) and the heightening blocks under all the hydraulic jacks two (12) can be removed; then, when all the hydraulic jacks two (12) are synchronously extended and supported downward to a supporting state, and all the hydraulic jacks one (11) are synchronously returned to the initial state, all the steel backing plates (4) and the heightening blocks under all the hydraulic jacks one (11) can be removed.

Images