Single-girder ultra-low double-span girder erection construction equipment and construction method

Abstract

The invention relates to single-girder ultra-low-position double-span girder erection construction equipment and a construction method, the single-girder ultra-low-position double-span girder erection construction equipment comprises a bridge girder erection machine, the bridge girder erection machine comprises a girder, a front auxiliary supporting leg, a front supporting leg, a middle supporting leg and a rear supporting leg, the front auxiliary supporting leg, the front supporting leg, the middle supporting leg and the rear supporting leg are sequentially connected to the girder from front to back, and the girder is further connected with a front crane car and a rear crane car which are used for hoisting box girders; the middle supporting leg is telescopic in height and is narrower than the box girder; the girder transporting vehicle comprises a front girder transporting vehicle and a rear girder transporting vehicle which are used for transporting box girders; and the conversion support comprises a front conversion support and a rear conversion support which are used for converting and supporting the to-be-erected box girder transported by the front girder transporting vehicle and the rear girder transporting vehicle above the erected box girder, and the front conversion support and the rear conversion support can lift the to-be-erected box girder to do lifting motion. When a special extremely-low-limit working condition is met, the box girder on the girder transporting vehicle is transferred to the front transfer support and the rear transfer support, the ground clearance of the box girder is further reduced, and the bridge erecting machine can erect the box girder under lower limit.

Description

Technical Field

[0001] The present application relates to the field of bridge construction equipment, and in particular to a single-main-beam ultra-low-position double-span beam erection construction equipment and a construction method. Background Art

[0002] With the increasingly complex construction environment of high-speed railways, intercity railways, and urban railroads, existing continuous ultra-low portal piers have appeared on the lines. In the direction along the bridge, the positions of the portal piers are sometimes overlapped with the bridge piers, and sometimes between the bridge piers. At the same time, the construction line is adjacent to the existing line, the distance between the bridge piers is small, and there are different height differences. The erection of the box girder is limited not only in the height direction, but also in the width direction. The working conditions of the entire line are extremely complex.

[0003] In the related technology, the middle leg of the single-girder bridge erection machine currently on the market is an O-shaped structure. In the traditional erection method, the front and rear cranes need to pass through the middle leg after taking the beam. However, due to the limit requirements of the line, the width of the middle leg cannot exceed the width of the box beam, and the height direction is also restricted, resulting in the height direction of the beam being restricted, and the box beam cannot pass through the middle leg. The traditional erection method cannot meet the erection requirements of this line, and the existing equipment and construction methods on the market cannot meet the erection requirements of this line. Summary of the invention

[0004] The embodiments of the present application provide a single-main-beam ultra-low-position double-span beam erection construction equipment and a construction method to solve the problem in the related art that a single-main-beam bridge erection machine is difficult to meet the requirements of beam erection construction in an environment with limited width and height.

[0005] A first aspect of an embodiment of the present application provides a single-main-beam ultra-low-position double-span beam erection construction equipment, comprising: A bridge erecting machine, the bridge erecting machine comprises a main beam, a front auxiliary leg, a front leg, a middle leg and a rear leg connected to the main beam in sequence from front to rear, a front crane and a rear crane for lifting a box beam are also connected to the main beam, the height of the middle leg is retractable and the width is smaller than the width of the box beam; A beam transport vehicle, the beam transport vehicle comprising a front beam transport vehicle and a rear beam transport vehicle for transporting box beams, the front beam transport vehicle and the rear beam transport vehicle are used to jointly transport the box beam to be erected to the bridge erection station where the bridge erection machine is located; The conversion support includes a front conversion support and a rear conversion support for converting the box beam to be erected transported by the front beam transport vehicle and the rear beam transport vehicle to the top of the erected box beam, and the front conversion support and the rear conversion support can lift the box beam to be erected for lifting and lowering motion.

[0006] In some embodiments: the middle leg comprises a frame assembly and a suspension assembly connected to each other, the frame assembly comprises an upper beam located at the top of the main beam, a lower beam located at the bottom of the main beam, and a telescopic support connected between the upper beam and the lower beam; The hanging assembly includes a hanging frame which is slidably connected to the upper cross beam in transverse direction and partially overlaps with the upper cross beam in height direction. The hanging frame is connected to the main beam through a lower support running mechanism and an upper support running mechanism and moves longitudinally relative to the main beam.

[0007] In some embodiments: an upper flange plate and a lower flange plate extending along the length direction of the main beam are respectively provided on both sides of the main beam, the lower support running mechanism is supported on the top surface of the lower flange plate, the upper support running mechanism is supported on the bottom surface of the upper flange plate, and a driving mechanism for driving the middle support leg to move longitudinally relative to the main beam is respectively provided on both sides of the hanging bracket.

[0008] In some embodiments: the front conversion support and the rear conversion support both include a pack beam frame for lifting the box beam to be erected, and support columns slidably connected to both ends of the pack beam, and a support is provided at the bottom of the support column, and a lifting cylinder is provided on the support to drive the pack beam frame to move up and down along the height direction of the support column.

[0009] In some embodiments: the front conversion support and the rear conversion support are respectively detachably connected to the front beam transport vehicle and the rear beam transport vehicle, the support column is provided with a plurality of positioning holes arranged in sequence from bottom to top, the positioning holes are interspersed with pins for positioning the support height of the pack beam frame, and the top of the pack beam frame is provided with a rubber pad for padding the box beam to be mounted.

[0010] In some embodiments: the bridge-building machine also includes a front auxiliary support leg located in front of the front support leg and moving along the length direction of the main beam, the top of the rear support leg is hinged to the tail end of the main beam through a rotating shaft, and when the beam transport vehicle transports the box beam to be erected into the bottom of the main beam, the rear support leg flips upward, and the front beam transport vehicle and the rear beam transport vehicle are respectively slidably connected with a front beam-carrying trolley and a rear beam-carrying trolley.

[0011] A second aspect of the embodiments of the present application provides a single main beam ultra-low position double-span beam erection construction method, the method using the single main beam ultra-low position double-span beam erection construction equipment described in any of the above embodiments, the method comprising: Use the front and middle legs to support the main beam, flip the rear legs upward, and the beam transport vehicle transports the box beam to the bottom of the bridge erecting machine, and the rear beam transport vehicle transports the box beam to the position; The rear outriggers flip downward and support themselves on the rear beam transport vehicle, the height of the rear beam transport vehicle is lowered, and the middle outriggers retract and retreat to a designated position away from the rear outriggers and stop; The front crane and the rear crane retreat to the beam-taking position above the front beam-transporting vehicle, and the front crane and the rear beam-transporting vehicle synchronously drag the box beam forward and make way for the support position of the middle outrigger; After the middle outrigger is extended, it stands on the rear beam transport vehicle and switches support with the rear outrigger. After the middle outrigger is extended and supported in place, the rear crane moves backward to the rear beam taking position to take the beam; The front crane and the rear crane lift the box girder and move forward to its position. The front crane and the rear crane align the box girder with the bridge pier and then drop the girder.

[0012] In some embodiments, the method further comprises: After the box beam falls into place, the front outrigger is anchored on the box beam, the front and rear outriggers support the main beam, the middle outrigger is shortened and suspended in the air and moves forward to the through-hole position to support the main beam, and then the rear outrigger is suspended in the air to prepare for the through-hole; The front outrigger and the middle outrigger drive the main beam to move forward longitudinally to the position, the front auxiliary outrigger moves backward synchronously, and the front crane and the rear crane move backward synchronously to the vicinity of the middle outrigger position; The front auxiliary outrigger moves forward to the center of the front pier and then supports the main beam; The rear outriggers, front outriggers and front auxiliary outriggers support the main beam, the middle outriggers are retracted off the ground, and the front and rear cranes and the middle outriggers move forward to the rear of the front outriggers; After the middle outrigger is extended to support the main beam, the anchoring of the front outrigger and the box beam is released, the front outrigger is longitudinally moved to the designated position of the front pier and then supports the main beam, the front auxiliary outrigger is retracted and suspended in the air, and longitudinally moved forward to the designated position; The front crane and the rear crane move forward longitudinally to the rear of the front outriggers, and the middle outriggers retract and move forward longitudinally again to the specified distance from the beam end to support the main beam; The top of the bridge-erecting machine rises to the beam-erecting height, and the rear legs flip upward, preparing for the erection of the next box beam.

[0013] A third aspect of the embodiments of the present application provides a single main beam ultra-low position double-span beam erection construction method, the method using the single main beam ultra-low position double-span beam erection construction equipment described in any of the above embodiments, the method comprising: Adjust the support height of the bridge erector according to the height of the structure to be passed through, flip the rear legs upward, use the beam transport vehicle to transport the box beam to the bottom of the bridge erector, and lower the cylinder legs of the front beam transport vehicle; The rear outriggers flip down and support on the bridge deck, the rear beam transport vehicle pushes the box beam forward to its position, and the front outriggers, middle outriggers and rear outriggers are alternately lowered to make the upper surface of the main beam of the bridge erecting machine reach the set distance from the bottom surface of the structure; The middle outrigger retracts and moves forward to the designated position, the front transfer support and the front beam transport vehicle transfer support, the box beam is separated from the front beam transport vehicle and supported on the front transfer support; The front beam transport vehicle moves forward to the beam end, stops and lowers the cylinder legs, drives the front beam-carrying trolley backward to the supporting position, and transfers the box beam on the front transfer support to the front beam-carrying trolley; The rear beam transport vehicle pushes the front beam carrying trolley to feed the beams into place synchronously, and the front conversion support moves into place synchronously; The front transfer support and the rear transfer support synchronously lift the box beam to detach from the front beam-carrying trolley and the rear beam-carrying trolley, and the front beam-carrying trolley and the rear beam-carrying trolley withdraw; The front and rear conversion supports are lowered to the lowest position, and the front and rear outriggers alternately lift the main beam to the beam erection height to provide space for the middle outrigger to retreat; The middle outrigger retreats a specified distance to reach the beam erection position, the middle outrigger extends and supports on the bridge deck, the front crane and the rear crane synchronously retreat to the beam removal position, ready to lift the box beam; The front crane and the rear crane lift the box beam and move it longitudinally forward to the beam dropping position. The front legs and the middle legs move the main beam horizontally to align the beam and drop it accurately.

[0014] In some embodiments, the method further comprises: After the box girder falls into place, the front outrigger is anchored on the box girder, and the bridge erection machine is lowered to the set distance between the upper surface of the main girder and the bottom surface of the structure. After the rear crane lifts the front conversion support and retreats to the designated position, the rear crane retracts the hook and returns; The rear crane moves to the rear of the front crane, the front and rear outriggers support the main beam, the middle outrigger is retracted and suspended in the air, and then moves forward longitudinally to the through-hole support position for support; The rear outriggers flip upwards, and the front beam transport vehicle and the rear beam transport vehicle enter the tail of the bridge erecting machine, pick up the front conversion support and the rear conversion support, and then exit; The front outrigger and the middle outrigger drive the main beam to move forward longitudinally to the position, the front auxiliary outrigger moves backward synchronously, and the front crane and the rear crane move backward to the vicinity of the middle outrigger; The front auxiliary outrigger moves forward to the center of the front pier and then supports the main beam; The rear outriggers are flipped downward to support the bridge deck, the middle outriggers are retracted off the ground, and the front crane and the rear crane and the middle outriggers are moved forward to the rear of the front outriggers; After the middle outrigger is extended to support the main beam, the anchoring of the front outrigger and the box beam is released, the front outrigger is longitudinally moved to the designated position of the front pier and then supports the main beam, the front auxiliary outrigger is retracted and suspended in the air, and longitudinally moved forward to the designated position; The front crane and the rear crane move forward longitudinally to the rear of the front outriggers, and the middle outriggers retract and move forward longitudinally again to a specified distance from the beam end to support the main beam; The top of the bridge-erecting machine rises to the beam-erecting height, and the rear legs flip upward, preparing for the erection of the next box beam.

[0015] The beneficial effects of the technical solution provided by this application include: The embodiment of the present application provides a single-main-beam ultra-low-position double-span beam erection construction equipment and a construction method. Since the single-main-beam ultra-low-position double-span beam erection construction equipment of the present application is provided with a bridge erection machine, the bridge erection machine includes a main beam, a front auxiliary support leg, a front support leg, a middle support leg and a rear support leg connected to the main beam from front to rear in sequence, and a front crane and a rear crane for lifting the box beam are also connected to the main beam, and the height of the middle support leg is retractable and the width is smaller than the width of the box beam; a beam transport vehicle, the beam transport vehicle includes a front beam transport vehicle and a rear beam transport vehicle for transporting the box beam, the front beam transport vehicle and the rear beam transport vehicle are used to jointly transport the box beam to be erected to the bridge erection station where the bridge erection machine is located; a conversion support, the conversion support includes a front conversion support and a rear conversion support for converting the box beam to be erected transported by the front beam transport vehicle and the rear beam transport vehicle to the top of the erected box beam, and the front conversion support and the rear conversion support can lift the box beam to be erected for lifting and lowering.

[0016] Therefore, the single-main-beam ultra-low-position double-span girder erection construction equipment of the present application is designed with a highly retractable middle leg whose width is less than the box girder width in response to the special working conditions of the line. The middle leg is designed to have an overall width less than the box girder width, and the ultra-low height requirement of the middle leg can be achieved by telescoping in the height direction, ultimately satisfying the lower part of the middle leg passing over the beam surface, the upper part passing through the limit portal pier, and finally supporting the rear beam transport vehicle or the bridge deck. The conversion support includes converting the box girder to be erected transported by the front beam transport vehicle and the rear beam transport vehicle to the front conversion support and the rear conversion support above the erected box girder. When encountering special extremely low limit working conditions, the box girder on the beam transport vehicle is transferred to the front conversion support and the rear conversion support, further reducing the height of the box girder, so that the bridge erection machine can achieve box girder erection under a lower limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is a structural schematic diagram of a beam transport vehicle cooperating with a beam erecting machine to erect beams in an embodiment of the present application; Figure 2 This is a schematic diagram of the structure of the beam-laying machine for converting the support to cooperate with the beam-laying machine in the embodiment of the present application; Figure 3 This is a structural front view of the supporting legs in the embodiment of the present application; Figure 4 This is a structural side view of the supporting legs in the embodiment of the present application; Figure 5 This is a structural front view of the conversion support of the embodiment of the present application; Figure 6 This is a structural side view of the front conversion support of the embodiment of the present application; Figure 7 This is a structural schematic diagram of step 1 in the first construction method of the embodiment of the present application; Figure 8 This is a structural schematic diagram of step 2 in the first construction method of the embodiment of the present application; Fig. 9 This is a structural schematic diagram of step 3 in the first construction method of the embodiment of the present application; Fig.10 This is a structural schematic diagram of step 4 in the first construction method of the embodiment of the present application; Fig.11 This is a structural schematic diagram of step 5 in the first construction method of the embodiment of the present application; Fig.12 This is a structural schematic diagram of step 6 in the first construction method of the embodiment of the present application; Fig.13 This is a structural schematic diagram of step 7 in the first construction method of the embodiment of the present application; Fig.14 This is a structural schematic diagram of step 8 in the first construction method of the embodiment of the present application; Fig.15 This is a structural schematic diagram of step 9 in the first construction method of the embodiment of the present application; Fig.16 This is a structural schematic diagram of step 10 in the first construction method of the embodiment of the present application; Fig.17 This is a structural schematic diagram of step 11 in the first construction method of the embodiment of the present application; Fig.18 This is a structural schematic diagram of step 12 in the first construction method of the embodiment of the present application; Fig.19 This is a structural schematic diagram of step 1 in the second construction method of the embodiment of the present application; Fig. 20 This is a structural schematic diagram of step 2 in the second construction method of the embodiment of the present application; Fig.21 This is a structural schematic diagram of step 3 in the second construction method of the embodiment of the present application; Fig. 22 This is a structural schematic diagram of step 4 in the second construction method of the embodiment of the present application; Fig.23 This is a structural schematic diagram of step 5 in the second construction method of the embodiment of the present application; Fig.24 This is a structural schematic diagram of step 6 in the second construction method of the embodiment of the present application; Fig.25 This is a structural schematic diagram of step 7 in the second construction method of the embodiment of the present application; Fig.26This is a structural schematic diagram of step 8 in the second construction method of the embodiment of the present application; Fig. 27 This is a structural schematic diagram of step 9 in the second construction method of the embodiment of the present application; Fig.28 This is a structural schematic diagram of step 10 in the second construction method of the embodiment of the present application; Fig.29 This is a structural schematic diagram of step 11 in the second construction method of the embodiment of the present application; Fig.30 This is a structural schematic diagram of step 12 in the second construction method of the embodiment of the present application; Fig.31 This is a structural schematic diagram of step 13 in the second construction method of the embodiment of the present application; Fig.32 This is a structural schematic diagram of step 14 in the second construction method of the embodiment of the present application; Fig.33 This is a structural schematic diagram of step 15 in the second construction method of the embodiment of the present application; Fig.34 This is a structural schematic diagram of step 16 in the second construction method of the embodiment of the present application; Fig.35 This is a structural schematic diagram of step 17 in the second construction method of the embodiment of the present application; Fig.36 This is a structural diagram of step 18 in the second construction method of an embodiment of the present application.

[0019] Reference numerals: 1. Front beam transport vehicle; 2. Rear beam transport vehicle; 3. Front auxiliary outriggers; 4. Front outriggers; 5. Main beam; 6. Front crane; 7. Rear crane; 8. Middle outriggers; 9. Rear outriggers; 10. Power system; 11. Front transfer support; 12. Rear transfer support; 81. Hanging frame; 82. Upper crossbeam; 83. Transverse cylinder; 84. Lower supporting running mechanism; 85. Telescopic support; 86. Lower crossbeam; 87. Driving mechanism; 88. Upper supporting running mechanism; 111. Support column; 112. Carrying beam frame; 113. Support; 114. Rubber pad; 115. Lifting cylinder; 116. Latch; 117. Cylinder base. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0021] The embodiments of the present application provide a single-main-beam ultra-low-position double-span beam erection construction equipment and a construction method, which can solve the problem in the related art that a single-main-beam bridge erection machine is difficult to meet the requirements of beam erection construction in an environment with limited width and height.

[0022] See also Figure 1 and Figure 2 As shown, the first aspect of the embodiment of the present application provides a single main beam ultra-low position double span beam erection construction equipment, comprising: The bridge erecting machine comprises a main beam 5, which is a single main beam, and a front leg 4, a middle leg 8 and a rear leg 9 connected to the main beam 5 from front to rear. The front leg 4 and the middle leg 8 can change their heights by telescoping, and can reciprocate forward and backward along the length direction of the main beam 5. The main beam 5 is also connected with a front crane 6 and a rear crane 7 for lifting the box beam. The front crane 6 and the rear crane 7 are used to lift the box beam transported by the beam transporter to a designated location.

[0023] The height of the middle support leg 8 is retractable and its width is smaller than the width of the box beam. The retractable height of the middle support leg 8 can not only adjust the supporting height of the main beam 5, but also reduce its own height by contraction to avoid the box beam transported by the transport vehicle. The width of the middle support leg 8 is smaller than the width of the box beam, so that the middle support leg 8 is located within the width range of the box beam to be erected, thereby avoiding the position interference with the surrounding structures due to the width exceeding the limit and failing to erect the beam normally.

[0024] The beam transport vehicle includes a front beam transport vehicle 1 and a rear beam transport vehicle 2 for transporting box beams. The front beam transport vehicle 1 and the rear beam transport vehicle 2 are used to jointly transport the box beam to be erected to the bridge erection station where the bridge erection machine is located. The front beam transport vehicle 1 and the rear beam transport vehicle 2 cooperate with each other to jointly carry and transport the box beam, and transport the right box beam prefabrication site of the box beam to the bridge erection station where the bridge erection machine is located.

[0025] The conversion support includes a front conversion support 11 and a rear conversion support 12 for converting the box beam to be erected transported by the front beam transport vehicle 1 and the rear beam transport vehicle 2 to the erected box beam or above the bridge deck. The front conversion support 11 and the rear conversion support 12 can lift the box beam to be erected. After the box to be erected transported by the front beam transport vehicle 1 and the rear beam transport vehicle 2 is converted to the front conversion support 11 and the rear conversion support 12, the height of the box to be erected from the ground can be further lowered to cooperate with the beam erecting machine to erect the beam at an ultra-low position.

[0026] The single-main-beam ultra-low-position double-span girder erection construction equipment of the embodiment of the present application is designed with a highly retractable middle leg 8 whose width is smaller than the box girder width in response to the special working conditions of the line. The middle leg 8 is designed to have an overall width smaller than the box girder width, and the ultra-low height requirement of the middle leg 8 can be achieved by retracting and extending in the height direction, ultimately satisfying the requirement that the lower part of the middle leg 8 passes over the beam surface, the upper part passes through the limit portal pier, and finally supports the rear beam transport vehicle 2 or the bridge deck.

[0027] The conversion support of the embodiment of the present application includes converting the box beam to be erected transported by the front beam transport vehicle 1 and the rear beam transport vehicle 2 to the front conversion support 11 and the rear conversion support 12 above the erected box beam. When encountering a special extremely low limit working condition, the box beam on the beam transport vehicle is converted to the front conversion support 11 and the rear conversion support 12, further reducing the height of the box beam, so that the bridge erection machine can realize the erection of the box beam under a lower limit.

[0028] In some alternative embodiments: See Figure 3 and Figure 4 As shown, the embodiment of the present application provides a single-main-beam ultra-low-position double-span beam erection construction equipment, the middle leg 8 of the equipment includes a frame assembly and a hanging assembly connected to each other. The frame assembly includes an upper beam 82 located at the top of the main beam 5, a lower beam 86 located at the bottom of the main beam 5, and a telescopic support 85 connected between the upper beam 82 and the lower beam 86. The telescopic support 85 can adjust the height between the upper beam 82 and the lower beam 86 by adjusting its own height.

[0029] The hanging assembly includes a hanging frame 81 which is slidably connected to the upper cross beam 82 in the horizontal direction and partially overlaps with the upper cross beam 82 in the height direction. The hanging frame 81 partially overlaps with the upper cross beam 82 in the height direction, which can further reduce the spatial height of the middle leg 8. A transverse oil cylinder 83 is provided between the hanging frame 81 and the upper cross beam 82 to push the hanging frame 81 to move horizontally. The transverse oil cylinder 83 pushes the hanging frame 81 to move horizontally relative to the upper cross beam 82, so as to realize the curved erection of the box beam. The hanging frame 81 is connected to the main beam 5 through the lower support running mechanism 84 and the upper support running mechanism 88 and moves longitudinally relative to the main beam 5.

[0030] An upper flange plate and a lower flange plate extending along the length direction of the main beam 5 are respectively provided on both sides of the main beam 5, and a lower support running mechanism 84 is supported on the top surface of the lower flange plate, and the lower support running mechanism 84 is used to hang the middle leg 8 on the main beam 5 for longitudinal movement. An upper support running mechanism 88 is supported on the bottom surface of the upper flange plate, and the upper support running mechanism 88 is used to vertically support the main beam 5 so that the main beam 5 moves longitudinally on the middle leg 8. A driving mechanism 87 for driving the middle leg 8 to move longitudinally relative to the main beam 5 is respectively provided on both sides of the hanging frame 81.

[0031] In some alternative embodiments: See Figure 5 and Figure 6As shown, the embodiment of the present application provides a single-main-beam ultra-low-position double-span beam erection construction equipment, the front conversion support 11 and the rear conversion support 12 of the equipment have the same structure, both of which include a beam-carrying frame 112 for lifting the box beam to be erected, and a support column 111 slidably connected to both ends of the beam-carrying frame 112. A support 113 is provided at the bottom of the support column 111, and a lifting cylinder 115 is provided on the support 113 to drive the beam-carrying frame 112 to move up and down along the height direction of the support column 111, and the bottom of the lifting cylinder 115 is fixed to the support 113 through a cylinder base 117.

[0032] The front conversion support 11 and the rear conversion support 12 are connected to the front beam transport vehicle 1 and the rear beam transport vehicle 2, respectively. At least two positioning holes arranged from bottom to top are provided on the support column 111, and a latch 116 for positioning the support height of the beam frame 112 is inserted into the positioning hole. The positioning hole at the bottom of the support column 111 is used to position the beam frame 112 at the lowest position of the ground clearance, and the positioning hole at the top of the support column 111 is used to position the beam frame 112 at the highest position of the ground clearance. A rubber pad 114 for padding the box beam to be mounted is provided on the top of the beam frame 112, and the rubber pad 114 is used to protect the box beam to be mounted and prevent the bottom from bumping.

[0033] In some alternative embodiments: See Figure 1 and Figure 2 As shown, the embodiment of the present application provides a single-main-beam ultra-low-position double-span girder erection construction equipment, the equipment's bridge erection machine also includes a front auxiliary leg 3 located in front of the front leg 4 and moving along the length direction of the main beam 5, the front auxiliary leg 3 is used to assist the bridge erection machine through the hole. The top of the rear leg 9 is hinged to the tail end of the main beam 5 through a rotating shaft. Before the beam transport vehicle transports the box beam to be erected into the bottom of the main beam 5, the rear leg 9 flips upward to provide space for the beam transport vehicle to feed the beam.

[0034] The front beam transport vehicle 1 and the rear beam transport vehicle 2 are slidably connected with the front beam support vehicle and the rear beam support vehicle, respectively. The front beam support vehicle and the rear beam support vehicle are slidably connected with the front beam transport vehicle 1 and the rear beam transport vehicle 2, respectively. The front beam support vehicle and the rear beam support vehicle are driven to slide by a winch or a jacking cylinder, so that the position of the box beam relative to the front beam transport vehicle 1 and the rear beam transport vehicle 2 can be adjusted, which is convenient for adjusting the lifting position of the box beam on site. A power system 10 is also provided at the rear end of the main beam 5, and the power system 10 can be used to generate electricity and provide a gas pressure source or a hydraulic source.

[0035] A second aspect of the embodiments of the present application provides a single main beam ultra-low position double-span beam erection construction method, the method using the single main beam ultra-low position double-span beam erection construction equipment described in any of the above embodiments, the method comprising: Step 1: See Figure 7As shown, the main beam 5 is supported by the front legs 4 and the middle legs 8, the rear legs 9 are flipped upward, the beam transport vehicle transports the box beam into the bottom of the bridge erecting machine, and the rear beam transport vehicle 2 delivers the box beam to its place.

[0036] Step 2: See Figure 8 As shown, the rear legs 9 are flipped downward and supported on the rear beam transport vehicle 2, the height of the rear beam transport vehicle 2 is lowered, and the middle legs 8 are retracted and retreated to a specified position away from the rear legs 9 and stop.

[0037] Step 3: See Fig. 9 As shown, the front crane 6 and the rear crane 7 retreat to the beam-taking position above the front beam transport vehicle 1, and the front crane 6 and the rear beam transport vehicle 2 synchronously drag the box beam forward and make way for the supporting position of the middle support leg 8.

[0038] Step 4: See Fig.10 As shown, after the middle outrigger 8 is extended, it stands on the rear beam transport vehicle 2 and switches support with the rear outrigger 9. After the middle outrigger 8 is extended and supported in place, the rear crane vehicle 7 retreats to the rear beam taking position to take the beam.

[0039] Step 5: See Fig.11 As shown, the front crane 6 and the rear crane 7 lift the box girder and move forward to their positions. The front crane 6 and the rear crane 7 align the box girder with the bridge pier and then drop the girder, thus completing the erection of the current box girder hole.

[0040] Step 6: See Fig.12 As shown, after the box girder falls into place, the front legs 4 are anchored on the box girder, the front legs 4 and the rear legs 9 support the main beam 5, the middle legs 8 are shortened and suspended and moved longitudinally forward to the through-hole position to support the main beam 5, and then the rear legs 9 are suspended in the air to prepare for the through-hole.

[0041] Step 7, see Fig.13 As shown, the front legs 4 and the middle legs 8 drive the main beam 5 to move forward longitudinally to the position, the front auxiliary legs 3 move backward synchronously, and the front crane 6 and the rear crane 7 move backward synchronously to the vicinity of the middle legs 8.

[0042] Step 8, see Fig.14 As shown, the front auxiliary support leg 3 moves forward to the center position of the front pier and then supports the main beam 5.

[0043] Step 9, see Fig.15 As shown, the rear legs 9, the front legs 4 and the front auxiliary legs 3 support the main beam 5, the middle legs 8 are retracted off the ground, and the front crane 6 and the rear crane 7 and the middle legs 8 move forward to the rear of the front legs 4.

[0044] Step 10, see Fig.16 As shown, after the middle leg 8 is extended to support the main beam 5, the anchoring of the front leg 4 and the box beam is released, and the front leg 4 is longitudinally moved to the designated position of the front pier to support the main beam 5, and the front auxiliary leg 3 is retracted and suspended in the air, and longitudinally moved forward to the designated position.

[0045] Step 11, see Fig.17 As shown, the front crane 6 and the rear crane 7 move forward longitudinally to the rear of the front support leg 4, and the middle support leg 8 is retracted and moves forward longitudinally again to a specified distance from the beam end to support the main beam 5.

[0046] Step 12, see Fig.18 As shown, the bridge erection machine is lifted to the beam erection height, and the rear support legs 9 are flipped upwards, completing the bridge erection machine passing through the hole and preparing for the erection of the next box beam.

[0047] A third aspect of the embodiments of the present application provides a single main beam ultra-low position double-span beam erection construction method, the method using the single main beam ultra-low position double-span beam erection construction equipment described in any of the above embodiments, the method comprising: Step 1: See Fig.19 As shown, the support height of the beam erecting machine is adjusted according to the height of the structure passing underneath (such as a portal pier or an erected bridge), the rear support leg 9 is flipped upward, the beam transport vehicle transports the box beam into the bottom of the bridge erecting machine, and the cylinder support leg of the front beam transport vehicle 1 is lowered.

[0048] Step 2: See Fig. 20 As shown, the rear support leg 9 is flipped downward and supported on the bridge deck, the rear beam transport vehicle 2 pushes the box beam forward to move into position, and the front support legs 4, the middle support legs 8 and the rear support legs 9 are alternately lowered so that the upper surface of the main beam 5 of the bridge erecting machine is at a set distance from the bottom surface of the structure.

[0049] Step 3: See Fig.21 As shown, the middle support leg 8 retracts and moves forward to the specified position, the front transfer support 11 and the front beam transport vehicle 1 transfer support, the box beam is separated from the front beam transport vehicle 1 and supported on the front transfer support 11.

[0050] Step 4: See Fig. 22 As shown, the front beam transport vehicle 1 moves forward to the beam end, stops and lowers the cylinder legs, drives the front beam-carrying trolley backward to the supporting position, and transfers the box beam on the front conversion support 11 to the front beam-carrying trolley.

[0051] Step 5: See Fig.23 As shown, the rear beam transport vehicle 2 pushes the front beam carrying trolley to synchronously feed the beams into place, and the front conversion support 11 runs into place synchronously.

[0052] Step 6: See Fig.24 As shown, the front conversion support 11 and the rear conversion support 12 synchronously lift the box beam to separate from the front beam-carrying trolley and the rear beam-carrying trolley, and the front beam-transporting trolley 1 and the rear beam-transporting trolley 2 withdraw.

[0053] Step 7, see Fig.25 As shown, the front transfer support and the rear transfer support are lowered to the lowest position, and the front legs and the rear legs alternately lift the main beam to the beam erection height to provide space for the middle legs to retreat.

[0054] Step 8, see Fig.26 As shown, the middle leg 8 retreats a specified distance to reach the beam erection position, the middle leg 8 is extended and supported on the bridge deck, and the front crane 6 and the rear crane 7 retreat synchronously to the beam removal position, ready to lift the box beam.

[0055] Step 9, see Fig. 27 As shown, the front crane 6 and the rear crane 7 lift the box beam and move forward longitudinally to the beam drop position, and the front support leg 4 and the middle support leg 8 move the main beam 5 horizontally to align and drop the beam accurately, completing the current box beam hole erection.

[0056] Step 10, see Fig.28 As shown, after the box girder falls into place, the front support leg 4 is anchored on the box girder, and the bridge erecting machine is lowered until the upper surface of the main beam 5 is at a set distance from the bottom surface of the structure. After the rear crane 7 lifts the front conversion support 11 and retreats to the specified position, the rear crane 7 retracts the hook and returns.

[0057] Step 11, see Fig.29 As shown, the rear crane 7 moves to the rear of the front crane 6, the front legs 4 and the rear legs 9 support the main beam 5, and the middle legs 8 are retracted and suspended in the air and then longitudinally moved forward to the through-hole support position for support.

[0058] Step 12, see Fig.30 As shown, the rear support leg 9 flips upward, and the front beam transport vehicle 1 and the rear beam transport vehicle 2 enter the tail of the bridge erecting machine, pick up the front conversion support 11 and the rear conversion support 12, and then exit.

[0059] Step 13, see Fig.31 As shown, the front legs 4 and the middle legs 8 drive the main beam 5 to move forward longitudinally to a position, while the front crane 6 and the rear crane 7 retreat to the vicinity of the middle legs 8.

[0060] Step 14, see Fig.32 As shown, the front auxiliary support leg 3 moves forward to the center position of the front pier and then supports the main beam 5.

[0061] Step 15, see Fig.33 As shown, the rear outrigger 9 is flipped downward and supported on the bridge deck, the middle outrigger 8 is retracted off the ground, and the front crane 6 and the rear crane 7 and the middle outrigger 8 move forward to the rear of the front outrigger 4.

[0062] Step 16, see Fig.34 As shown, after the middle leg 8 is extended to support the main beam 5, the anchoring of the front leg 4 and the box beam is released, and the front leg 4 is longitudinally moved to the designated position of the front pier to support the main beam 5, and the front auxiliary leg 3 is retracted and suspended in the air, and longitudinally moved forward to the designated position.

[0063] Step 17, see Fig.35As shown, the front crane 6 and the rear crane 7 move forward longitudinally to the rear of the front support leg 4, and the middle support leg 8 is retracted and moves forward longitudinally again to a specified distance from the beam end to support the main beam 5.

[0064] Step 18, see Fig.36 As shown, the bridge erection machine is lifted to the beam erection height, the rear support legs 9 are flipped upward, the bridge erection machine completes the hole crossing, and is ready to erect the next hole box beam.

[0065] How it works The embodiment of the present application provides a single-main-beam ultra-low-position double-span beam erection construction equipment and a construction method. Since the single-main-beam ultra-low-position double-span beam erection construction equipment of the present application is provided with a bridge erection machine, the bridge erection machine includes a main beam 5, a front support leg 4, a middle support leg 8 and a rear support leg 9 connected to the main beam 5 from front to rear in sequence, and the main beam 5 is also connected with a front crane 6 and a rear crane 7 for lifting the box beam, and the height of the middle support leg 8 is retractable and the width is smaller than the width of the box beam; a beam transport vehicle, the beam transport vehicle includes a front beam transport vehicle 1 and a rear beam transport vehicle 2 for transporting the box beam, the front beam transport vehicle 1 and the rear beam transport vehicle 2 are used to jointly transport the box beam to be erected to the bridge erection station where the bridge erection machine is located; a conversion support, the conversion support includes a front conversion support 11 and a rear conversion support 12 for converting the box beam to be erected transported by the front beam transport vehicle 1 and the rear beam transport vehicle 2 to support the conversion of the box beam to be erected above the erected box beam, and the front conversion support 11 and the rear conversion support 12 can lift the box beam to be erected for lifting and lowering movements.

[0066] Therefore, the single-main-beam ultra-low-position double-span girder erection construction equipment of the present application is designed with a highly retractable middle leg 8 whose width is less than the box girder width in view of the special working conditions of the line. The middle leg 8 is designed to have an overall width less than the box girder width, and the ultra-low height requirement of the middle leg 8 can be achieved by telescoping in the height direction, ultimately satisfying the lower part of the middle leg 8 passing over the beam surface, the upper part passing through the limit portal pier, and finally supporting the rear beam transport vehicle 2 or the bridge deck. The conversion support includes converting the box girder to be erected transported by the front beam transport vehicle 1 and the rear beam transport vehicle 2 to the front conversion support 11 and the rear conversion support 12 above the erected box girder. When encountering special extremely low limit working conditions, the box girder on the beam transport vehicle is converted to the front conversion support 11 and the rear conversion support 12, further reducing the height of the box girder from the ground, so that the bridge erection machine can smoothly realize the box girder erection under a lower limit.

[0067] In the description of the present application, it should be noted that the terms "upper", "lower", etc. 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 application and simplifying the description, rather than indicating or implying 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 on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0068] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0069] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A single main beam ultra-low position double span beam erection construction equipment, characterized in that: include: A bridge erecting machine, the bridge erecting machine comprising a main beam (5), a front auxiliary support leg (3), a front support leg (4), a middle support leg (8) and a rear support leg (9) connected to the main beam (5) in sequence from front to rear, the main beam (5) also being connected to a front crane (6) and a rear crane (7) for lifting a box beam, the middle support leg (8) being retractable in height and having a width smaller than the width of the box beam; A beam transport vehicle, the beam transport vehicle comprising a front beam transport vehicle (1) and a rear beam transport vehicle (2) for transporting box beams, the front beam transport vehicle (1) and the rear beam transport vehicle (2) being used to jointly transport the box beam to be erected to a bridge erection station where a bridge erection machine is located; A conversion support, the conversion support comprising a front conversion support (11) and a rear conversion support (12) for converting a box beam to be erected that is transported by a front beam transport vehicle (1) and a rear beam transport vehicle (2) to an upper portion of an erected box beam, the front conversion support (11) and the rear conversion support (12) being capable of lifting the box beam to be erected for lifting and lowering movements.

2. The single-main-beam ultra-low-position double-span beam erection construction equipment according to claim 1, characterized in that: The middle leg (8) comprises a frame assembly and a suspension assembly connected to each other, the frame assembly comprising an upper crossbeam (82) located at the top of the main beam (5), a lower crossbeam (86) located at the bottom of the main beam (5), and a telescopic support (85) connected between the upper crossbeam (82) and the lower crossbeam (86); The hanging assembly comprises a hanging frame (81) which is slidably connected to the upper cross beam (82) in a transverse direction and partially overlaps with the upper cross beam (82) in a height direction; the hanging frame (81) is connected to the main beam (5) via a lower support running mechanism (84) and an upper support running mechanism (88) and moves longitudinally relative to the main beam (5).

3. The single-main-beam ultra-low-position double-span beam erection construction equipment according to claim 2, characterized in that: An upper flange plate and a lower flange plate extending along the length direction of the main beam (5) are respectively provided on both sides of the main beam (5); the lower support running mechanism (84) is supported on the top surface of the lower flange plate; the upper support running mechanism (88) is supported on the bottom surface of the upper flange plate; and a driving mechanism (87) for driving the middle support leg (8) to move longitudinally relative to the main beam (5) is respectively provided on both sides of the hanging frame (81).

4. The single-main-beam ultra-low-position double-span beam erection construction equipment according to claim 1, characterized in that: The front conversion support (11) and the rear conversion support (12) both include a beam support frame (112) for supporting the box beam to be erected, and support columns (111) slidably connected to both ends of the beam support frame (112), a support (113) being provided at the bottom of the support column (111), and a lifting cylinder (115) being provided on the support (113) for driving the beam support frame (112) to move up and down along the height direction of the support column (111).

5. The single-main-beam ultra-low-position double-span beam erection construction equipment according to claim 4, characterized in that: The front conversion support (11) and the rear conversion support (12) are detachably connected to the front beam transport vehicle (1) and the rear beam transport vehicle (2), respectively; the support column (111) is provided with a plurality of positioning holes arranged in sequence from bottom to top; the positioning holes are penetrated by latches (116) for positioning the support height of the beam carrier frame (112); and the top of the beam carrier frame (112) is provided with a rubber pad (114) for padding the box beam to be mounted.

6. The single-main-beam ultra-low-position double-span beam erection construction equipment according to claim 1, characterized in that: The top of the rear support leg (9) is hinged to the tail end of the main beam (5) via a rotating shaft. When the beam transport vehicle transports the box beam to be erected and enters below the main beam (5), the rear support leg (9) flips upward, and the front beam transport vehicle (1) and the rear beam transport vehicle (2) are respectively slidably connected to a front beam-carrying trolley and a rear beam-carrying trolley.

7. A method for constructing a single main beam with ultra-low position and double spans, characterized in that: The method uses the single-main-beam ultra-low-position double-span beam erection construction equipment according to any one of claims 1 to 6, and the method comprises: The main beam (5) is supported by the front supporting legs (4) and the middle supporting legs (8), the rear supporting legs (9) are turned upward, the beam transport vehicle transports the box beam into the bottom of the bridge erecting machine, and the rear beam transport vehicle (2) transports the box beam to the desired position; The rear outrigger (9) turns downward and is supported on the rear beam transport vehicle (2), and the middle outrigger (8) retracts and retreats to a designated position away from the rear outrigger (9) and stops; The front crane (6) and the rear crane (7) retreat to the beam-removing position above the front beam-transporting vehicle (1), and the front crane (6) and the rear beam-transporting vehicle (2) synchronously drag the box beam forward and make way for the support position of the middle support leg (8); After the middle outrigger (8) is extended, it stands on the rear beam transport vehicle (2) and switches support with the rear outrigger (9). After the middle outrigger (8) is extended and supported in place, the rear lifting vehicle (7) retreats to the rear beam taking position to take the beam; The front crane (6) and the rear crane (7) lift the box girder and move forward to the position. The front crane (6) and the rear crane (7) align the box girder with the bridge pier and then drop the girder.

8. A single main beam ultra-low position double span beam erection construction method as claimed in claim 7, characterized in that: The method further comprises: After the box beam is lowered into place, the front legs (4) are anchored on the box beam, the front legs (4) and the rear legs (9) support the main beam (5), the middle legs (8) are shortened and suspended in the air and moved forward to the through-hole position to support the main beam (5), and then the rear legs (9) are suspended in the air to prepare for the through-hole; The front outrigger (4) and the middle outrigger (8) drive the main beam (5) to move forward longitudinally to a position, the front auxiliary outrigger (3) moves backward synchronously, and the front crane (6) and the rear crane (7) move backward synchronously to the vicinity of the position of the middle outrigger (8); The front auxiliary support leg (3) moves forward to the center of the front pier and then supports the main beam (5); The rear outriggers (9), the front outriggers (4) and the front auxiliary outriggers (3) support the main beam (5), the middle outriggers (8) are retracted off the ground, and the front crane (6) and the rear crane (7) and the middle outriggers (8) move forward to the rear of the front outriggers (4); After the middle outrigger (8) is extended to support the main beam (5), the anchoring of the front outrigger (4) and the box beam is released, the front outrigger (4) is longitudinally moved to a designated position of the front pier and then supports the main beam (5), and the front auxiliary outrigger (3) is retracted and suspended in the air and longitudinally moved forward to a designated position; The front crane (6) and the rear crane (7) move forward longitudinally to the rear of the front outrigger (4), and the middle outrigger (8) retracts and moves forward longitudinally again to a specified distance from the beam end to support the main beam (5); The top of the bridge erecting machine is raised to the beam erection height, and the rear legs (9) are turned upwards to prepare for the erection of the next box beam.

9. A method for constructing a single main beam with ultra-low position and double spans, characterized in that: The method uses the single-main-beam ultra-low-position double-span beam erection construction equipment according to any one of claims 1 to 6, and the method comprises: The supporting height of the bridge erecting machine is adjusted according to the height of the structure to be passed through, the rear support leg (9) is turned upward, the beam transport vehicle transports the box beam into the bottom of the bridge erecting machine, and the oil cylinder support leg of the front beam transport vehicle (1) is lowered; The rear outrigger (9) is flipped downward and supported on the bridge deck, the rear beam transport vehicle (2) pushes the box beam forward to move into position, and the front outrigger (4), the middle outrigger (8) and the rear outrigger (9) are alternately lowered so that the upper surface of the main beam (5) of the bridge erecting machine is at a set distance from the bottom surface of the structure; The middle support leg (8) is retracted and moves forward to a specified position, the front transfer support (11) and the front beam transport vehicle (1) transfer support, the box beam is separated from the front beam transport vehicle (1) and supported on the front transfer support (11); The front beam transport vehicle (1) moves forward to the beam end, stops and lowers the oil cylinder legs, drives the front beam carrying trolley backward to the supporting position, and transfers the box beam on the front transfer support (11) to the front beam carrying trolley; The rear beam transport vehicle (2) pushes the front beam carrying trolley to synchronously feed the beam into position, and the front conversion support (11) moves synchronously into position; The front conversion support (11) and the rear conversion support (12) synchronously lift the box beam to separate from the front beam-carrying trolley and the rear beam-carrying trolley, and the front beam-carrying trolley (1) and the rear beam-carrying trolley (2) withdraw; The front conversion support (11) and the rear conversion support (12) are lowered to the lowest position, and the front legs (4) and the rear legs (9) alternately lift the main beam (5) to the beam erection height, thereby providing space for the middle legs (8) to retreat; After the middle outrigger (8) retreats a specified distance, it reaches the beam erection position, the middle outrigger (8) is extended and supported on the bridge deck, and the front crane (6) and the rear crane (7) synchronously retreat to the beam removal position, ready to lift the box beam; The front crane (6) and the rear crane (7) lift the box beam and move it longitudinally forward to the beam drop position, and the front support leg (4) and the middle support leg (8) move the main beam (5) transversely to the position and drop the beam accurately.

10. A single main beam ultra-low position double span beam erection construction method as claimed in claim 9, characterized in that: The method further comprises: After the box girder falls into place, the front outrigger (4) is anchored on the box girder, and the bridge erection machine is lowered until the upper surface of the main girder (5) is at a set distance from the bottom surface of the structure, and the rear crane (7) lifts the front conversion support (11) and moves backward to the designated position, and then the rear crane (7) retracts the hook and returns; The rear crane (7) moves to the rear of the front crane (6), the front outriggers (4) and the rear outriggers (9) support the main beam (5), and the middle outriggers (8) are retracted and suspended in the air and then longitudinally moved forward to the through-hole support position for support; The rear outrigger (9) turns upward, and the front beam transport vehicle (1) and the rear beam transport vehicle (2) enter the rear of the bridge erecting machine, pick up the front conversion support (11) and the rear conversion support (12), and then exit; The front outrigger (4) and the middle outrigger (8) drive the main beam (5) to move forward longitudinally to a position, the front auxiliary outrigger (3) moves backward synchronously, and at the same time, the front crane (6) and the rear crane (7) move backward to the vicinity of the middle outrigger (8); The front auxiliary support leg (3) moves forward to the center of the front pier and then supports the main beam (5); The rear outrigger (9) is turned downward to be supported on the bridge deck, the middle outrigger (8) is retracted off the ground, and the front crane (6) and the rear crane (7) and the middle outrigger (8) are moved forward to the rear of the front outrigger (4); After the middle outrigger (8) is extended to support the main beam (5), the anchoring of the front outrigger (4) and the box beam is released, the front outrigger (4) is longitudinally moved to a designated position of the front pier and then supports the main beam (5), and the front auxiliary outrigger (3) is retracted and suspended in the air and longitudinally moved forward to a designated position; The front crane (6) and the rear crane (7) move forward longitudinally to the rear of the front outrigger (4), and the middle outrigger (8) retracts and moves forward longitudinally again to a specified distance from the beam end to support the main beam (5); The top of the bridge erecting machine is raised to the beam erection height, and the rear legs (9) are turned upwards to prepare for the erection of the next box beam.

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