Installation method of tower crane for cast-in-place box girder construction of ultra-wide viaduct

Abstract

The present invention relates to an installation method for a tower crane of a cast-in-situ box girder of an ultra-wide viaduct. When constructing the piers, four pier part embedded supports are pre-buried on the upper end surface of the piers, and the upper ends of the pier part embedded supports protrude from the upper end surface of the piers. When constructing the end cross beam of the cast-in-situ box girder, four cross beam part embedded supports are pre-buried in the end cross beam of the cast-in-situ box girder, and a rectangular steel frame with positioning steel plates arranged at four corners supporting the upper ends of the four cross beam part embedded supports is pre-buried. The lower ends of the cross beam part embedded supports extend out of the lower surface of the end cross beam of the cast-in-situ box girder. The pier part embedded supports are detachably connected to the cross beam part embedded supports, and the installation of the tower crane for the cast-in-situ box girder construction is realized by supporting the four support points at the bottom of the tower crane for the cast-in-situ box girder construction through the four positioning steel plates one by one. The present invention has the advantages of not occupying the road surfaces on both sides of the road, having a large lifting radius and a large load-bearing capacity, and solving the problem that the tower crane cannot be installed for the ultra-wide box girder without the tower crane installation space beside the viaduct.

Description

Technical Field

[0001] The present invention relates to the field of construction technology, and particularly relates to an installation method for a tower crane for cast-in-place box girders of an ultra-wide viaduct. Background Art

[0002] With the rapid development of the economy, urban roads and viaducts are being built wider and wider. At special intersections of the on- and off-ramps, the overall width of the cast-in-place box girder of the viaduct exceeds 60 m (hereinafter referred to as the ultra-wide box girder). Installing a tower crane beside the pier of the cast-in-place box girder for transporting construction materials and small mechanical equipment is a mature and efficient construction method. However, for existing ground roads with traffic and close to high-voltage transmission lines, the construction environment is complex, and the installation of the tower crane foundation for the construction of the ultra-wide cross-section cast-in-place box girder faces difficulties in setting up. For this reason, in engineering practice, there have been cases of erecting the tower crane through pre-drilled holes in the wing slabs of the cast-in-place box girder. However, for ultra-wide bridges, the method of opening holes in the wing slabs is also difficult to meet the requirements of the lifting radius and lifting weight for the construction of ultra-wide box girders. Summary of the Invention

[0003] The present invention aims to provide an installation method for a tower crane for cast-in-place box girders of an ultra-wide viaduct supported by foot piers, which does not occupy the road surfaces on both sides of the road, has a large lifting radius and a large load-bearing capacity, and solves the problem that the tower crane cannot be installed for ultra-wide box girders without installation space beside the viaduct.

[0004] The above technical problems are solved by the following technical solutions: an installation method for a tower crane for cast-in-place box girders of an ultra-wide viaduct, the viaduct includes piers and cast-in-place box girder end crossbeams, a bearing is provided at the center of the upper end surface of the pier, the cast-in-place box girder end crossbeam is supported on the bearing, and both longitudinal bridge sides of the cast-in-place box girder end crossbeam extend beyond the bearing. It is characterized in that when constructing the pier, two pairs of pier part embedded supports distributed along the longitudinal bridge direction on both sides of the support are embedded in the upper end surface of the pier, the two pier part embedded supports of the same pair of pier part embedded supports are distributed along the transverse bridge direction, and the upper ends of the pier part embedded supports protrude from the upper end surface of the pier. When constructing the cast-in-place box girder end crossbeam, four crossbeam part embedded supports are embedded in the cast-in-place box girder end crossbeam, and a rectangular steel frame is embedded in the cast-in-place box girder end crossbeam, and four corners of the rectangular steel frame are respectively supported on the upper ends of the four crossbeam part embedded supports. The rectangular steel frame includes four positioning steel plates arranged at the four corners of the upper end of the rectangular steel frame. The lower ends of the crossbeam part embedded supports extend out of the lower surface of the cast-in-place box girder end crossbeam, and the parts of the four pier part embedded supports protruding from the upper end surface of the pier are detachably connected to the parts of the four crossbeam part embedded supports extending out of the lower surface of the cast-in-place box girder end crossbeam respectively. The upper surfaces of the positioning steel plates are flush with the upper surface of the cast-in-place box girder end crossbeam, and the installation of the tower crane for the cast-in-place box girder is realized by respectively supporting the four support points at the bottom of the tower crane for the cast-in-place box girder through the four positioning steel plates.

[0005] Preferably, the embedded support of the pier part includes an upper connecting ear located above the upper end surface of the pier. The embedded support of the crossbeam part is provided with a lower connecting ear located below the lower surface of the cast-in-place box girder end crossbeam. The lower connecting ear is provided with a pin hole in the lower connecting ear part, and the upper connecting ear is provided with a pin hole in the upper connecting ear part. A horizontal connecting pin is inserted into the pin hole in the lower connecting ear part and the pin hole in the upper connecting ear part to detachably connect the part of the embedded support of the pier part extending above the upper end surface of the pier and the part of the embedded support of the crossbeam part extending out of the cast-in-place box girder end crossbeam together.

[0006] Preferably, there are two upper connecting ears, and the upper connecting ears are located between the two lower connecting ears.

[0007] Preferably, one end of the horizontal connecting pin is integrally formed with a fixed stop block, and the other end is threadedly connected with a movable stop block. The upper connecting ear and the lower connecting ear are located between the movable stop block and the fixed stop block. The fixed stop block and the movable stop block are used to prevent the horizontal connecting pin from falling off. The connection is reliable.

[0008] Preferably, the embedded support of the pier part further includes a pier part steel plate cast on the upper end surface of the pier, four anchor bolts passing through the four corners of the pier part steel plate, an I-beam extending along the bridge transverse direction placed on the pier part steel plate, a pressing steel plate placed on both ends of the I-beam and sleeved on two of the anchor bolts in a one-to-one correspondence at both ends, and nuts threadedly connected to the anchor bolts. The nuts press down the pressing steel plate so that the pressing steel plate presses on the I-beam. The two anchor bolts passing through the same pressing steel plate are distributed on both sides of the I-beam along the bridge longitudinal direction. The lower ends of the anchor bolts are cast in the pier. Two steel connecting seats distributed along the bridge transverse direction are welded on the I-beam. The lower connecting ear is made of steel structure, and each of the steel connecting seats is welded with the lower connecting ear. The I-beam includes an upper horizontal wall plate, a vertical connecting plate and a lower horizontal wall plate connected in an "I" shape; after the construction tower crane of the cast-in-place box girder is removed after use, the horizontal connecting pin is pulled out, the nuts are unscrewed, and the I-beam and the pressing steel plate are removed. So that the parts of the embedded support of the pier part except the anchor bolts and the pier part steel plate can be disassembled for reuse. It not only has good economy, but also can conveniently maintain the original appearance of the bridge.

[0009] Preferably, the length of the anchor bolt located in the pier is more than 60 cm.

[0010] Preferably, the lower end of the anchor bolt is provided with an elbow, and the elbows of every two anchor bolts are hooked on a steel bar cast in the pier and extending in the horizontal direction. It can improve the connection reliability between the embedded support of the pier part and the pier.

[0011] Preferably, a steel backing plate is also sleeved on the anchor bolt, and the steel backing plate is located between the pressing steel plate and the nut.

[0012] Preferably, the beam part embedded support further includes two beam part steel plates cast in the end beam of the cast-in-place box girder. The upper connecting ear is made of steel structure, and the upper connecting ear is welded to the beam part steel plate. The rectangular steel frame includes four lower support steel plates arranged at the four corners of the lower end of the rectangular steel frame. The lower support steel plates respectively support on the beam part steel plates of the four beam part embedded supports. There are two pairs of beam part through holes distributed along the longitudinal direction of the bridge on the beam part steel plate. A total of four beam part through holes in the two pairs of beam part through holes are arranged in a rectangle. The two beam part through holes in the same pair of beam part through holes are distributed along the transverse direction of the bridge. The lower support steel plate covers the lower end of the beam part through hole. The lower end of the beam part through hole is butted with a vertical threaded sleeve welded to the beam part steel plate. When the lower end of the vertical threaded sleeve supports on the steel connecting seat, the pin holes of the upper connecting ear part and the pin holes of the lower connecting ear part are at the same horizontal height. The dimension of the lower connecting ear along the transverse direction of the bridge is equal to the interval distance between the two vertical threaded sleeves aligned with the two beam part through holes in the same pair of beam part through holes. When the lower connecting ear is located between the two vertical threaded sleeves aligned with the two beam part through holes in the same pair of beam part through holes, the pin holes of the upper connecting ear part and the pin holes of the upper connecting ear part are coaxial. Two positioning baffles distributed along the longitudinal direction of the bridge are detachably connected to the steel connecting seat. The lower connecting ear is located between the two positioning baffles. The upper end of the positioning baffle is higher than the upper end of the lower connecting ear. The lower end of the vertical threaded sleeve is lower than the lower end of the upper connecting ear. The process of assembling the end beam of the cast-in-place box girder to the pier is as follows: Pull out the two positioning baffles. When the lower end of the upper connecting ear is higher than the upper end of the upper connecting ear, move the end beam of the cast-in-place box girder along the transverse direction of the bridge until the gap between the lower connecting ear and the two vertical threaded sleeves aligned with the two beam part through holes in the same pair of beam part through holes is aligned. Then move the end beam of the cast-in-place box girder along the longitudinal direction of the bridge to align the pin holes of the lower connecting ear part and the pin holes of the upper connecting ear part, and connect the positioning baffle located in front of the moving direction of the end beam of the cast-in-place box girder to the steel connecting seat. Move the end beam of the cast-in-place box girder until the vertical thread is butted with the positioning baffle connected to the steel connecting seat. Pull out the positioning baffle connected to the steel connecting seat. Lower the end beam of the cast-in-place box girder until the vertical threaded sleeve supports on the steel connecting seat. At this time, the pin holes of the upper connecting ear part are aligned with the pin holes of the lower connecting ear part. Insert the connecting pin into the pin holes of the lower connecting ear part and the pin holes of the upper connecting ear part to connect the pier part embedded support and the beam part embedded support together. After the tower crane for the cast-in-place box girder construction is removed after use, thread the threaded jack onto the vertical threaded sleeve and jack up the lower support steel plate so that the beam part steel plate falls off from the end beam of the cast-in-place box girder. This technical solution can not only improve the convenience when aligning the pin holes of the upper connecting ear part and the pin holes of the lower connecting ear part, but also realize the recycling of the beam part steel plate and the upper connecting ear of the steel connection. In order to make it labor-saving to remove the beam part steel plate, the beam part steel plate needs to be thin. If it is thin, the thread is easily damaged if a thread is set in the beam part through hole. This technical solution solves this problem well by setting the vertical threaded sleeve, and the vertical threaded sleeve can also play a positioning role, realizing the dual use of one thing.It has a simple structure and can be conveniently positioned for embedding in the end cross beam of the cast-in-place box girder, and is reliable and stable when supporting the rectangular frame.

[0013] Preferably, positioning pins are provided on the lower support steel plates and are correspondingly inserted into the steel plates of the cross beam part, which can improve the convenience of positioning the steel plates of the cross beam part and the rectangular steel frame during manufacturing.

[0014] Preferably, the rectangular steel frame includes four vertical steel beams distributed in a quadrilateral shape, four upper horizontal steel beams distributed in a "mouth" shape, and four lower horizontal steel beams distributed in a "mouth" shape. The two ends of the upper horizontal steel beams are correspondingly connected to the upper ends of two of the vertical steel beams, and the two ends of the lower horizontal steel beams are correspondingly connected to the lower ends of two of the vertical steel beams. The four lower support steel plates are correspondingly welded to the lower end faces of the four vertical steel beams, the four lower support steel plates are correspondingly supported on the four embedded support points of the cross beam part, the four positioning steel plates are correspondingly welded to the upper end faces of the four vertical steel beams, the vertical steel beams connected to the same upper horizontal steel beam are connected together by an inclined steel beam, and the upper ends of the four vertical steel beams are correspondingly connected to the four ends of the upper cross, and the lower ends are correspondingly connected to the four ends of the lower cross. It has good structural strength.

[0015] The beneficial effects of the present invention are as follows: First, the pier column and the end cross beam of the cast-in-place box girder are used to set up the tower crane foundation to support the tower crane, which can meet the working radius and lifting capacity requirements of the lifting equipment for the construction of the ultra-wide cast-in-place beam, improve the use efficiency of the tower crane and ensure construction safety at the same time; Second, the present invention can quickly remove the parts exposed outside the bridge, restore the design functions of the box girder and the pier column, and at the same time achieve the maximum turnover utilization of the components, with good energy conservation and environmental protection and good social benefits; It does not occupy the surrounding land and has good environmental protection. Description of the Drawings

[0016] Figure 1 It is a partial structural schematic diagram of the embedded tower crane foundation supported by the foot pier in the first embodiment of the present invention;

[0017] Figure 2 It is an enlarged schematic diagram of the embedded support point of the pier part;

[0018] Figure 3 It is a schematic diagram of the rectangular frame;

[0019] Figure 4 It is a schematic diagram when the embedded support point of the pier part and the embedded support point of the cross beam part in the second embodiment are sectioned through the vertical plane in the transverse bridge direction, and the positioning baffle is not installed in the figure;

[0020] Figure 5 It is a schematic diagram when the embedded support point of the pier part and the embedded support point of the cross beam part in the second embodiment are sectioned through the vertical plane in the longitudinal bridge direction.

[0021] In the figure: pier 1, embedded support point 2 at the pier part, steel plate 3 at the pier part, anchor bolt 4, I-beam 30, coping steel plate 5, steel backing plate 6, nut 7, elbow 28, steel bar 9, steel connection seat 10, lower connection ear 11, pin hole 12 at the lower connection ear part, upper horizontal wall plate 13, vertical connection plate 14, lower horizontal wall plate 15, steel plate 16 at the crossbeam part, upper connection ear 17, horizontal connection pin 18, fixed stop block 19, movable stop block 20, vertical steel beam 29, upper horizontal steel beam 21, lower horizontal steel beam 22, lower support steel plate 23, positioning steel plate 24, inclined steel beam 25, upper cross 26, lower cross 27, through hole 31 at the crossbeam part, positioning pin 32, vertical threaded sleeve 33, positioning baffle 34. Specific implementation mode

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Example 1, see Figures 1 to 3 , an installation method for a tower crane of a cast-in-place box girder of an extra-wide viaduct, which is realized by an embedded tower crane foundation supported by a foot pier. The embedded tower crane foundation supported by a foot pier includes a pier 1 (only the upper end face of the pier 1 is drawn to observe the components of the present invention inside the pier) and a cast-in-place box girder end crossbeam (not drawn in the figure). A support (not drawn) is provided at the center of the upper end face of the pier, and the cast-in-place box girder end crossbeam is supported on the support, and both longitudinal bridge sides of the cast-in-place box girder end crossbeam extend beyond the support.

[0024] On the upper end surface of the pier, there are two pairs of pier part embedded supports distributed along the longitudinal bridge direction on both sides of the support. The two pier part embedded supports of the same pair of pier part embedded supports are distributed along the transverse bridge direction (the transverse bridge direction is the width direction of the bridge deck), and the upper ends of the pier part embedded supports protrude from the upper end surface of the pier. Specifically: The pier part embedded support includes a pier part steel plate 3 cast on the upper end surface of the pier, four anchor bolts 4 passing through the four corners of the pier part steel plate, an I-beam 30 extending along the transverse bridge direction and resting on the pier part steel plate, two pressing steel plates 5 respectively sleeved on two of the anchor bolts at both ends and resting on the two ends of the I-beam, a steel backing plate 6 sleeved on the anchor bolt, and a nut 7 threadedly connected to the anchor bolt. The steel backing plate is located between the pressing steel plate and the nut. The nut presses down the pressing steel plate through the steel backing plate so that the pressing steel plate presses on the I-beam. The two anchor bolts passing through the same pressing steel plate are distributed on both sides of the I-beam along the longitudinal bridge direction (the longitudinal bridge direction is the extending direction of the bridge), and the lower ends of the anchor bolts are cast in the pier. The length of the anchor bolt located in the pier is more than 60 cm. The lower end of the anchor bolt is provided with an elbow 28, and the elbows of every two anchor bolts are hooked on a steel bar 9 cast in the pier and extending horizontally. Two steel connection seats 10 distributed along the transverse bridge direction are welded on the I-beam. One steel connection seat is provided with two lower connection ears 11 distributed along the transverse bridge direction, and the lower connection ear is provided with a lower connection ear part pin hole 12. The lower connection ear is made of steel structure, and the steel connection seat is welded together with the lower connection ear. The I-beam includes an upper horizontal wall plate 13, a vertical connecting plate 14, and a lower horizontal wall plate 15 connected in an "I" shape.

[0025] Four beam part embedded supports are embedded in the cast-in-place box girder end cross beam. Four rectangular steel frames are also embedded in the cast-in-place box girder end cross beam, with the four corners respectively supported on the upper ends of the four beam part embedded supports. The beam part embedded support includes two beam part steel plates 16 cast in the cast-in-place box girder end cross beam. An upper connection ear 17 is connected to the beam part steel plate. The upper connection ear is made of steel structure, and the beam part steel plate is welded together with the upper connection ear. The lower connection ear is located below the lower surface of the cast-in-place box girder end cross beam. The upper connection ear is provided with an upper connection ear part pin hole. One upper connection ear is located between two lower connection ears connected to the same steel connection seat.

[0026] When the cast-in-place box girder end cross beam is assembled onto the pier, two lower connecting lugs on a steel connecting seat and the upper connecting lug located between the two lower connecting lugs are connected together by a horizontal connecting pin 18. Specifically, the horizontal connecting pin (a steel pin) is simultaneously inserted into the pin holes of the lower connecting lug part and the upper connecting lug part to detachably connect the part of the embedded support point of the pier part extending out of the upper end face of the pier and the part of the embedded support point of the cross beam part extending out of the cast-in-place box girder end cross beam. One end of the horizontal connecting pin is integrally formed with a fixed stop block 19, and the other end is threadedly connected with a movable stop block 20. The upper connecting lug and the lower connecting lug are located between the movable stop block and the fixed stop block, and the fixed stop block and the movable stop block are used to prevent the horizontal connecting pin from falling off. After unscrewing the movable stop block, the horizontal connecting pin can be pulled out.

[0027] The rectangular steel frame includes four vertical steel beams 29 distributed in a quadrilateral shape, four upper horizontal steel beams 21 distributed in a "mouth" shape, and four lower horizontal steel beams 22 distributed in a "mouth" shape. The two ends of the upper horizontal steel beams are welded to the upper ends of two vertical steel beams in a one-to-one correspondence. The two ends of the lower horizontal steel beams are welded to the lower ends of two vertical steel beams in a one-to-one correspondence. Lower support steel plates 23 are welded to the lower end faces of the vertical steel beams, and the four lower support steel plates support on the four embedded support points of the cross beam part (specifically, on the two cross beam part steel plates of the embedded support point of the cross beam part) in a one-to-one correspondence. Positioning steel plates 24 are welded to the upper ends of the vertical steel beams. The vertical steel beams connected to the same upper horizontal steel beam are welded to the two ends of an inclined steel beam 25. The upper ends of the four vertical steel beams are welded to the four ends of the upper cross 26 in a one-to-one correspondence, and the lower ends are welded to the four ends of the lower cross 27 in a one-to-one correspondence. The upper surface of the positioning steel plate is flush with the upper surface of the cast-in-place box girder end cross beam.

[0028] The four support points at the bottom of the cast-in-place box girder construction tower crane support on the four positioning steel plates in a one-to-one correspondence to fix the tower crane on the embedded tower crane foundation supported by the foot pier, thereby realizing the installation of the cast-in-place box girder construction tower crane.

[0029] After the bridge construction is completed, the tower crane is removed. After unscrewing the movable stop block, the horizontal connecting pin is pulled out. After unscrewing the nuts, the components of the embedded support point of the pier part except for the anchor bolts, horizontal steel bars, and pier part steel plates are removed for turnover use. The part of the upper connecting lug and the anchor bolt protruding from the pier part steel plate is cut off, and the exposed parts of the components of the embedded support point of the pier part remaining on the pier and the exposed components of the embedded support point of the cross beam part remaining on the cast-in-place box girder end cross beam are subjected to rust prevention treatment.

[0030] Embodiment 2, the difference from Embodiment 1 is:

[0031] See Figure 4 and Figure 5, there are two pairs of beam - part through - holes 31 longitudinally distributed along the bridge on the steel plate of the beam part. A total of four beam - part through - holes in the two pairs of beam - part through - holes are arranged in a rectangular distribution, and the two beam - part through - holes in the same pair of beam - part through - holes are distributed transversely across the bridge. The lower support steel plate is provided with positioning pins 32 that are respectively inserted into the beam - part steel plate. The support steel plate covers the lower end of the beam - part through - hole. The lower end of the beam - part through - hole is butted with a vertical thread sleeve 33 welded to the beam - part steel plate. When the lower end of the vertical thread sleeve supports on the steel connection seat, the upper connection ear pin hole and the lower connection ear pin hole are at the same horizontal height. The dimension of the lower connection ear in the transverse direction of the bridge is equal to the interval distance between the two vertical thread sleeves aligned with the two beam - part through - holes in the same pair of beam - part through - holes. When the lower connection ear is located between the two vertical thread sleeves aligned with the two beam - part through - holes in the same pair of beam - part through - holes, the upper connection ear pin hole and the upper connection ear pin hole are coaxial. Two positioning baffles 34 distributed longitudinally along the bridge are detachably connected to the steel connection seat. The lower connection ear is located between the two positioning baffles. The upper end of the positioning baffle is higher than the upper end of the lower connection ear, and the lower end of the vertical thread sleeve is lower than the lower end of the upper connection ear. The process of assembling the cast - in - place box - girder end beam to the pier is as follows: Pull out the two positioning baffles. Move the cast - in - place box - girder end beam transversely across the bridge with the lower end of the upper connection ear higher than the upper end of the upper connection ear until it is aligned with the gap between the two vertical thread sleeves aligned with the two beam - part through - holes in the same pair of beam - part through - holes. Then move the cast - in - place box - girder end beam longitudinally to align the lower connection ear pin hole and the upper connection ear pin hole, and connect the positioning baffle located in front of the moving direction of the cast - in - place box - girder end beam to the steel connection seat. Move the cast - in - place box - girder end beam until the vertical thread sleeve is butted with the positioning baffle connected to the steel connection seat. Pull out the positioning baffle connected to the steel connection seat, and lower the cast - in - place box - girder end beam until the vertical thread sleeve supports on the steel connection seat. At this time, the upper connection ear pin hole is aligned with the lower connection ear pin hole. Insert the connecting pin into the lower connection ear pin hole and the upper connection ear pin hole to connect the pier - part embedded support point and the beam - part embedded support point together. After the construction tower crane for the cast - in - place box - girder is removed after use, a screw jack is also thread - connected to the vertical thread sleeve to jack up the lower support steel plate so that the beam - part steel plate falls off from the cast - in - place box - girder end beam.

Claims

1. An installation method for a tower crane in the construction of a cast-in-place box girder of an ultra-wide viaduct. The viaduct includes bridge piers and end cross beams of the cast-in-place box girder. A bearing is provided at the center of the upper end surface of the bridge pier, and the end cross beam of the cast-in-place box girder is supported on the bearing. Both longitudinal bridge sides of the end cross beam of the cast-in-place box girder extend beyond the bearing. It is characterized in that, When constructing the pier, two pairs of pier part embedded supports distributed longitudinally along the bridge on both sides of the support are pre-embedded on the upper end surface of the pier. The two pier part embedded supports of the same pier part embedded support pair are distributed transversely along the bridge. The upper ends of the pier part embedded supports protrude from the upper end surface of the pier. When constructing the cast-in-place box girder end crossbeam, four crossbeam part embedded supports are pre-embedded in the cast-in-place box girder end crossbeam, and a rectangular steel frame is pre-embedded in the cast-in-place box girder end crossbeam, with four corners corresponding to and supported on the upper ends of the four crossbeam part embedded supports respectively. The rectangular steel frame includes four positioning steel plates arranged at the four corners of the upper end of the rectangular steel frame. The lower ends of the crossbeam part embedded supports extend out of the lower surface of the cast-in-place box girder end crossbeam. The parts of the four pier part embedded supports protruding from the upper end surface of the pier are detachably connected to the parts of the four crossbeam part embedded supports extending out of the cast-in-place box girder end crossbeam respectively. The upper surfaces of the positioning steel plates are flush with the upper surface of the cast-in-place box girder end crossbeam. The installation of the cast-in-place box girder construction tower crane is realized by supporting the four support points at the bottom of the cast-in-place box girder construction tower crane on the four positioning steel plates respectively.

2. The installation method of the tower crane for the cast-in-place box girder of the ultra-wide viaduct according to claim 1, characterized in that, The pier part embedded support includes an upper connecting ear located above the upper end surface of the pier. The crossbeam part embedded support is provided with a lower connecting ear located below the lower surface of the cast-in-place box girder end crossbeam. The lower connecting ear is provided with a lower connecting ear part pin hole, and the upper connecting ear is provided with an upper connecting ear part pin hole. A horizontal connecting pin is inserted into the lower connecting ear part pin hole and the upper connecting ear part pin hole to detachably connect the part of the pier part embedded support protruding from the upper end surface of the pier and the part of the crossbeam part embedded support extending out of the cast-in-place box girder end crossbeam. There are two upper connecting ears, and the two upper connecting ears are located between the two lower connecting ears.

3. The installation method of the tower crane for the cast-in-place box girder of the ultra-wide viaduct according to claim 2, characterized in that, One end of the horizontal connecting pin is integrally formed with a fixed stop block, and the other end is threadedly connected with a movable stop block. The upper connecting ear and the lower connecting ear are located between the movable stop block and the fixed stop block. The fixed stop block and the movable stop block are used to prevent the horizontal connecting pin from falling off.

4. The installation method of the tower crane for the cast-in-place box girder of the ultra-wide viaduct according to claim 2 or 3, characterized in that, The pier part embedded support further includes a pier part steel plate cast on the upper end surface of the pier, four anchor bolts passing through the four corners of the pier part steel plate, an I-beam extending transversely along the bridge and placed on the pier part steel plate, a pressing steel plate placed at both ends of the I-beam and sleeved on two of the anchor bolts respectively at both ends, and nuts threadedly connected to the anchor bolts. The nuts press down the pressing steel plate so that the pressing steel plate presses on the I-beam. The two anchor bolts passing through the same pressing steel plate are distributed longitudinally along the bridge on both sides of the I-beam. The lower ends of the anchor bolts are cast in the pier. Two steel connecting seats distributed transversely along the bridge are welded on the I-beam. The lower connecting ear is made of steel structure, and each steel connecting seat is welded with the lower connecting ear. The I-beam includes an upper horizontal wall plate, a vertical connecting plate and a lower horizontal wall plate connected in an "I" shape. After the cast-in-place box girder construction tower crane is removed after use, the horizontal connecting pin is pulled out, the nuts are unscrewed, and the I-beam and the pressing steel plate are removed.

5. The installation method of the tower crane for cast-in-place box girder construction of the ultra-wide viaduct according to claim 4, characterized in that, The length of the anchor bolt located in the pier is more than 60 cm.

6. The installation method of the tower crane for the cast-in-place box girder of the ultra-wide viaduct according to claim 4, characterized in that, The lower end of the anchor bolt is provided with an elbow, and the elbows of every two anchor bolts are hooked on a steel bar cast horizontally in the pier.

7. The installation method of the tower crane for the cast-in-place box girder of the ultra-wide viaduct according to claim 4, characterized in that, A steel backing plate is also sleeved on the anchor bolt, and the steel backing plate is located between the coping steel plate and the nut.

8. The installation method of the tower crane for cast-in-place box girders of the ultra-wide viaduct according to claim 4, characterized in that, The embedded support of the crossbeam part further includes two crossbeam part steel plates cast in the end crossbeam of the cast-in-place box girder. The upper connecting ear is made of steel structure, and the upper connecting ear is welded on the crossbeam part steel plate. The rectangular steel frame includes four lower support steel plates arranged at the four corners of the lower end of the rectangular steel frame. The lower support steel plates respectively support on the crossbeam part steel plates of the four embedded supports of the crossbeam part. There are two pairs of crossbeam part through holes distributed along the longitudinal direction of the bridge on the crossbeam part steel plate. A total of four crossbeam part through holes in the two pairs of crossbeam part through holes are arranged in a rectangle. The two crossbeam part through holes in the same pair of crossbeam part through holes are distributed along the transverse direction of the bridge. The lower support steel plate covers the lower end of the crossbeam part through hole. The lower end of the crossbeam part through hole is butted with a vertical threaded sleeve welded on the crossbeam part steel plate. When the lower end of the vertical threaded sleeve supports on the steel connection seat, the pin holes of the upper connecting ear part and the pin holes of the lower connecting ear part are at the same horizontal height. The size of the lower connecting ear along the transverse direction of the bridge is equal to the interval distance between the two vertical threaded sleeves aligned with the two crossbeam part through holes in the same pair of crossbeam part through holes. When the lower connecting ear is located between the two vertical threaded sleeves aligned with the two crossbeam part through holes in the same pair of crossbeam part through holes, the pin holes of the upper connecting ear part and the pin holes of the upper connecting ear part are coaxial. Two positioning baffles distributed along the longitudinal direction of the bridge are detachably connected to the steel connection seat. The lower connecting ear is located between the two positioning baffles. The upper end of the positioning baffle is higher than the upper end of the lower connecting ear. The lower end of the vertical threaded sleeve is lower than the lower end of the upper connecting ear. The process of assembling the end crossbeam of the cast-in-place box girder to the pier is as follows: Pull out the two positioning baffles. When the lower end of the upper connecting ear is higher than the upper end of the upper connecting ear, move the end crossbeam of the cast-in-place box girder along the transverse direction of the bridge until it is aligned with the gap between the two vertical threaded sleeves aligned with the two crossbeam part through holes in the same pair of crossbeam part through holes. Then move the end crossbeam of the cast-in-place box girder along the longitudinal direction of the bridge to align the pin holes of the lower connecting ear part and the pin holes of the upper connecting ear part, and connect the positioning baffle located in front of the moving direction of the end crossbeam of the cast-in-place box girder to the steel connection seat. Move the end crossbeam of the cast-in-place box girder until the vertical thread is butted with the positioning baffle connected to the steel connection seat. Pull out the positioning baffle connected to the steel connection seat. Move the end crossbeam of the cast-in-place box girder downward until the vertical threaded sleeve supports on the steel connection seat. At this time, the pin holes of the upper connecting ear part are aligned with the pin holes of the lower connecting ear part. Insert the connecting pin into the pin holes of the lower connecting ear part and the pin holes of the upper connecting ear part to connect the embedded support of the pier part and the embedded support of the crossbeam part together. After the tower crane for the cast-in-place box girder construction is removed after use, the threaded jack is also threadedly connected to the vertical threaded sleeve to jack up the lower support steel plate so that the crossbeam part steel plate falls off from the end crossbeam of the cast-in-place box girder.

9. The installation method of the tower crane for the cast-in-place box girder of the ultra-wide viaduct according to claim 8, characterized in that, Positioning pins are provided on the lower support steel plates and are respectively inserted into the crossbeam part steel plates.

10. The installation method of the tower crane for cast-in-place box girder construction of the ultra-wide viaduct according to claim 8, characterized in that, The rectangular steel frame includes four vertical steel beams distributed in a quadrilateral shape, four upper horizontal steel beams distributed in a "square" shape, and four lower horizontal steel beams distributed in a "square" shape. The two ends of the upper horizontal steel beams are correspondingly connected to the upper ends of two of the vertical steel beams, and the two ends of the lower horizontal steel beams are correspondingly connected to the lower ends of two of the vertical steel beams. The four lower support steel plates are correspondingly welded to the lower end faces of the four vertical steel beams, and the four lower support steel plates are correspondingly supported on four embedded supports of the crossbeam parts. The four positioning steel plates are correspondingly welded to the upper end faces of the four vertical steel beams. The vertical steel beams connected to the same upper horizontal steel beam are connected together by an inclined steel beam. The upper ends of the four vertical steel beams are correspondingly connected to the four ends of the upper cross, and the lower ends are correspondingly connected to the four ends of the lower cross.

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