CN112144413A - Whole-span in-situ splicing and erecting method for steel-concrete composite beam in mountainous area - Google Patents

Abstract

The invention discloses a full-span in-situ assembly and erection method of a steel-concrete composite beam in a mountainous area. The invention uses a temporary steel pipe pier and a Bailey sheet platform as the first assembly platform to place a liftable pedestal, and then uses a tower crane to hoist the steel main beam components The first-span steel girder is assembled on this platform. After the first-span steel girder is assembled, a liftable pedestal and a beam transporter are set up on the first-span steel-concrete composite girder as the assembly of other span steel girder. Platform, after the other span steel main beams are assembled, put down the foldable liftable pedestal outside the beam transporter, transport the other span steel main beams to the corresponding position for installation, and so on, until the last steel span of a chain is installed. Concrete composite beams, and then cast integral wet joints uniformly. The in-situ assembling and framing construction method of the steel-concrete composite beam not only solves the problems of construction safety and quality, but also has the advantages of high efficiency, saving construction costs, and the like.

Description

An in-situ assembly and erection method for the whole span of a steel-concrete composite beam in mountainous areas

technical field

The invention relates to a full-span in-situ assembly and erection method for a steel-concrete composite beam, in particular to a full-span in-situ assembly and erection method for a steel-concrete composite beam in mountainous areas.

Background technique

With the rapid development of infrastructure construction in my country, in order to actively respond to the supply-side reform proposed by the state and adapt to the new normal of economic development. There will be more and more forms and numbers of steel structure bridges, and various construction techniques and methods will appear. The superstructure of these bridges is complex and diverse, and the steel-concrete composite girder is the most representative one. In this structure, the steel main girder of the present invention is composed of three I-beams and a simply supported girder bridge. The rigidity and stability of a single steel main beam itself are poor, so this structure must be installed and formed over the entire span at one time. The commonly used construction method of this structure is to use the gantry crane hoisting method for the entire span after assembly. However, when using gantry cranes for hoisting construction, the environment and site requirements are relatively high, but the mountainous terrain is steep, and many places do not have the conditions for gantry crane hoisting construction. Therefore, it is necessary to A new approach addresses this technical problem.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for in-situ assembly and erection of the entire span of a steel-concrete composite beam in a mountainous area. The method can use the tower crane to assemble and install the steel-concrete composite beam when the terrain in the mountainous area is steep and the gantry crane hoisting construction conditions are not available. It has the characteristics of reducing construction period, reducing construction cost and improving construction safety and quality.

The technical scheme of the present invention: a method for in-situ assembling and erecting of the entire span of a steel-concrete composite beam in a mountainous area, which specifically includes the following steps:

A. Set up a plurality of temporary piers of steel pipe piles at the position of the first span, set up Bailey sheet platforms on the temporary piers of steel pipe piles, and set up tower cranes with corresponding hoisting capacity beside the first span;

B. Permanent supports are arranged on the cover beams at both ends of the beret platform, and a certain number of liftable pedestals are arranged on the belay platform between the permanent supports;

C. Set the initial height of each liftable pedestal according to the pre-camber line, and use the tower crane to assemble the steel main beam above the liftable pedestal;

D. After the steel main beam is assembled and before the bridge deck is installed, calculate the deflection value of the steel main beam according to the theory, lower the height of each liftable pedestal in advance, and then use the tower crane to hoist the precast concrete bridge deck. After the bridge deck is installed, the liftable pedestal Supports the whole span steel main beam;

E. After the bridge deck on the steel main girder is installed, weld the longitudinal and transverse steel bars of the adjacent bridge decks to make all the bridge decks of the whole span form a whole;

F. After the welding of steel bars is completed, the concrete at the notch of the shear nails is reserved for the cast-in-place bridge deck, and the bridge deck is consolidated on the steel main beam to form the first-span steel-concrete composite beam;

G. Arrange a foldable liftable pedestal on the assembled first-span steel-concrete composite beam;

H. Arrange beam transport trolleys at both ends of the steel-concrete composite beam of the first span, and assemble the steel main beam of the second span on the foldable liftable pedestal;

I. After the second-span steel main girder is assembled, lower the height of the foldable elevating pedestal and lay it down on the bridge deck, and transport the entire span of the steel main girder to the bottom of the bridge erecting machine through the beam transport trolley. The bridge machine realizes the erection of the whole span steel main beam;

J. After the steel girder of the second span is erected, the bridge deck is installed, and at the same time, the beam transport trolley is moved back to the steel-concrete composite girder of the first span, ready to assemble the steel girder of the next span, and the bridge erection machine is moved forward to prepare for the erection of the next span steel main beam;

K. Repeat steps H to J to realize the erection and installation of a steel-concrete composite beam;

L. Remove the liftable pedestal and pour the whole wet joint at one time.

In the aforementioned in-situ assembly and erection method for the entire span of a steel-concrete composite beam in mountainous areas, the bridge erection machine adopts a widened bridge erection machine.

In the above-mentioned method for in-situ assembling and erecting of steel-concrete composite beams in the entire span of the mountainous area, in the step H, other span steel main beams are assembled on the beam transporting trolley and the foldable liftable platform 7 .

In the aforesaid method for in-situ assembly and erection of the entire span of the steel-concrete composite beam in the mountainous area, in step J, after the erection of the second-span steel main beam is completed, the precast concrete bridge deck is hoisted to the second-span steel main beam by a tower crane and passed through the frame The bridge crane is used for laying; after the other span steel main beams are erected, the bridge deck transport trolley is hoisted to the second span steel-concrete composite beam by the tower crane, and then the precast concrete bridge deck is hoisted to the bridge deck transport trolley by the tower crane. , The bridge deck transport trolley transports the precast concrete bridge deck to the bridge erection machine, and the bridge deck is laid by the bridge erection machine. After the bridge deck is laid, the bridge deck transport trolley is hoisted away by the tower crane.

In the above-mentioned method for in-situ assembling and erecting of steel-concrete composite beams in the entire span of the mountainous area, the foldable elevating platform 7 includes two bases spaced and parallel along the width direction of the steel-concrete composite beams, and the bases include a top and a bottom. The steel plate, the top and bottom steel plates are connected by a plurality of steel pipes arranged at intervals, each steel pipe is inserted with a screw rod, the screw thread is sleeved with an adjusting nut, the top of the screw rod is fixed with a steel plate, and the base is placed on the steel backing plate The outer side is connected with the steel backing plate through hinges.

In the above-mentioned method for assembling and erecting the entire span of the steel-concrete composite beam in the mountainous area, the two screws in the same cross section are connected by screw connection members, and the screw connection members include nuts that are threaded on the screws. A sleeve is fixedly connected to the side, and the two sleeves are connected by a connecting screw.

In the above-mentioned method for in-situ assembly and erection of the whole span of the steel-concrete composite beam in the mountainous area, the two bases are connected by a plurality of base connectors, and the base connectors include a connecting steel plate, and one end of the connecting steel plate is connected to one of the bases. The top steel plate is fixedly connected, and the other end is connected with the top steel plate of the other base through a latch.

In the aforesaid method for in-situ assembling and erecting of steel-concrete composite beams in the entire span of the mountainous area, the base also includes an abdominal steel plate, and the abdominal steel plate is arranged between or outside the adjacent two steel pipes, and the sides thereof are connected with the steel pipes, and the top and bottom surfaces are connected with the steel pipes. Connect with top and bottom steel plates.

In the above-mentioned method for in-situ assembling and erecting of the steel-concrete composite beam in the entire span of the mountainous area, the steel backing plate is fixed on the surface of the steel-concrete composite beam by means of expansion bolts.

Beneficial effects of the present invention: Compared with the prior art, the present invention firstly utilizes the erected temporary steel pipe pier and the Bailey sheet platform as the first assembling platform, firstly setting bridge permanent supports at both ends of the platform, and the permanent supports are arranged between the permanent supports. Place a number of liftable pedestals according to the needs, and then use the tower crane to hoist the steel main beam components to assemble the first-span steel main beam on this platform. After the first-span steel main beam is assembled, the tower crane is hoisted to complete the bridge deck. Pavement, and then set up a liftable pedestal and a beam transporter on the first-span steel-concrete composite beam as an assembly platform for the second-span steel main beam. The second-span steel main girder is transported to the corresponding position for installation, and then the bridge erecting machine moves forward to prepare to erect the next-span girder. Prepare to assemble the steel main beam of the third span, and so on, until the last span of the steel-concrete composite beam of the unit is installed, and then pour the whole unit of wet joints uniformly.

In the whole assembly process, except for the steel main beam of the first span, which is operated on the inner thunder sheet platform, the steel main beams of other spans are all assembled on the steel-concrete composite beam platform of the first span. The construction is safe and the quality is good. It is well guaranteed; during the whole assembly process, the hoisting of materials is realized by tower cranes, and there is no need to install gantry cranes, which saves construction costs.

In general, the in-situ assembling and framing construction method of the steel-concrete composite beam not only solves the problems of construction safety and quality, but also has the advantages of high efficiency and saving construction costs.

Description of drawings

Accompanying drawing 1 is the schematic diagram of setting up temporary pier of steel pipe pile and Bailey sheet platform;

Accompanying drawing 2 is the schematic diagram of arranging permanent support and liftable pedestal;

Accompanying drawing 3 is the schematic diagram of assembling steel main beam;

Accompanying drawing 4 is the schematic diagram of lowering the height of the liftable pedestal and installing the bridge deck;

Accompanying drawing 5 is the schematic diagram of arranging foldable elevating pedestal, beam transporting flat car and assembling 2# steel main beam;

Accompanying drawing 6 is the schematic diagram of erecting 2# steel main beam;

Accompanying drawing 7 is the schematic diagram of assembling 3# steel main beam;

8 is a schematic structural diagram of a foldable elevating pedestal;

Accompanying drawing 9 is the side structure schematic diagram of accompanying drawing 8;

Accompanying drawing 10 is the structural representation of base;

Figure 11 is a schematic cross-sectional view of Figure 10;

12 is a schematic structural diagram of a screw connection member;

FIG. 13 is a schematic structural diagram of the base connector.

Reference numerals: 1- steel pipe pile temporary pier, 2- Bailey sheet platform, 3- tower crane, 4- permanent support 5- liftable pedestal, 6-steel main beam, 7-foldable liftable pedestal, 701- Screw, 702-steel plate, 703-base, 704-steel backing plate, 705-hinge, 706-screw connecting member, 707-base connecting piece, 708-top and bottom steel plate, 709-steel pipe, 710-web steel plate, 711-nut, 712-sleeve, 713-connecting screw, 714-connecting steel plate, 715-bolt, 716-adjusting nut, 717-expansion bolt, 8-beam transporting trolley, 9-bridge erecting machine.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but not as a basis for limiting the present invention.

Embodiments of the present invention: a method for in-situ assembly and erection of a steel-concrete composite beam in a mountainous area, as shown in the accompanying drawings 1-7, specifically comprising the following steps:

A. As shown in Figure 1, a plurality of temporary piers 1 of steel pipe piles are erected at the first span position, a Bailey sheet platform 2 is set up on the temporary piers 1 of steel pipe piles, and a tower crane 3;

B. As shown in accompanying drawing 2, be provided with permanent support 4 on the cover beam (abutment) at both ends of the beret platform 2, and then set a certain number of Liftable pedestal 5;

C. As shown in Figure 3, according to the design, the steel main beam 6 has a certain pre-camber for assembly. Therefore, the initial height of each liftable pedestal 5 is set according to the pre-camber line, and the steel main beam 6 is assembled above the liftable pedestal 5 after the tower crane 3 is used to lift the material;

D. As shown in FIG. 4, according to the theoretical calculation results, after the steel main beam 6 is superimposed on the second-stage constant-load precast concrete deck, the steel main beam 6 will have corresponding downward deflection. Therefore, after the steel main beam 6 is assembled and before the bridge deck is installed, the deflection value of the steel main beam 6 is theoretically calculated, and the height of each liftable platform 5 is lowered in advance, and then the tower crane 3 is used to hoist the precast concrete bridge deck. The liftable pedestal 5 supports the whole-span steel main beam 6;

E. After the bridge deck on the steel main girder 6 is installed, weld the longitudinal and transverse steel bars of the adjacent bridge decks, so that all the bridge decks in the whole span form a whole and enhance the stability;

F. After the welding of the steel bars is completed, the concrete at the notch of the shear nails is reserved for the cast-in-place bridge deck, and the bridge deck is consolidated on the steel main beam 6 to form the first-span steel-concrete composite beam, so that the steel main beam 6 and the bridge deck are formed. Can be co-stressed under subsequent working conditions;

G. As shown in accompanying drawing 5, on the assembled first span steel-concrete composite beam, a foldable elevating platform 7 is arranged;

H. The beam transporting trolley 8 is arranged at both ends of the first span steel-concrete composite beam, and the second span steel main beam 6 is assembled on the foldable liftable platform 7;

1. As shown in accompanying drawing 6, after the second span steel main beam 6 is assembled, the height of the foldable elevating platform 7 is lowered and put down on the bridge deck, so that the assembled steel main beam 6 is fully supported on the On the beam transporting trolley 8, then the whole-span steel main beam 6 is transported to the bottom of the bridge erecting machine 9 by the beam transporting trolley 8, and the whole-span steel main girder 6 erection work is realized by the bridge erecting machine 9;

J. as shown in accompanying drawing 7, install the bridge deck after the second span steel main beam 6 is erected, and the beam transporting trolley 8 retreats to the first span steel-concrete composite beam simultaneously, and is ready to assemble the next span steel main beam 6, After the bridge deck is paved, the bridge erection machine 9 is moved forward to prepare to erect the next span steel main beam 6;

K. Repeat steps H to J to realize the erection and installation of a steel-concrete composite beam;

L. Remove the liftable pedestal 5, release the temporarily supported liftable pedestal 5 of the first span steel main beam, and cast the whole wet joint at one time. According to the force mechanism of continuous beams, the wet joints can only be poured at one time after the erection of a steel-concrete composite beam.

In the whole method, due to the steep terrain, it is impossible to install equipment such as gantry cranes. Therefore, the temporary pier 1 of steel pipe piles and the Bailey sheet platform 2 are installed to form the first assembly platform. Combined with the use of tower crane 3, the first assembly platform can be used to complete the first assembly platform. The assembly of a span steel main beam 6 .

During the whole process, the liftable pedestal 5 is set to achieve different pre-cambers under the two working conditions of the first span steel main beam 6 assembly and the bridge deck installation. The load is transmitted to the lower Bailey sheet platform 2 . The lifting function is realized by the liftable pedestal 5, so as to facilitate the later dismantling construction.

The foldable elevating pedestal 7 can be laid down laterally on the bridge deck after the steel girder 6 of each span is assembled, so that the beam transporting trolley 8 can smoothly span from above when transporting the entire span of the steel girder 6 . The foldable elevating platform 7 is used to support the steel main beam 6 during the assembly process of the steel main beam 6 during use.

After each span of steel main beam 6 is assembled, the entire span of steel main beam 6 cannot be hoisted to the beam transport trolley 8, so it is necessary to gradually assemble the remaining span steel main beams on the beam transport trolley 8 and the foldable liftable platform 7 6.

After the transportation of the steel main beams 6 of each span is completed, the beam transporting trolley 8 returns to the original position of the steel-concrete composite beams of the first span before the assembling work of the steel main beams 6 of the next span can be started.

The steel-concrete composite beam of the first span and the Bailey sheet platform 2 below together act as the assembled platform of each other span, and jointly bear the load in the process. The Bailey sheet platform 2 supports the first-span steel girder 6 to prevent excessive load during construction, resulting in irreversible deformation of the first-span steel girder 6 .

Due to the poor stability of the single steel main beam 6, the whole span assembly and erection method is adopted.

The bridge erecting machine 9 adopts a widening bridge erecting machine to meet the erection requirements of the whole-width and full-span steel main beam 6 .

In the step H, other cross-steel main beams 6 are assembled on the beam transporting trolley 8 and the foldable liftable platform 7 . The beam transporting trolley 8 and the foldable liftable pedestal 7 together serve as the support system during the assembly process of the steel main beam 6. When the steel main beam 6 of each span is assembled, the foldable liftable pedestal 7 is lowered and made Deflection, the whole is laid down on the bridge deck. At this time, the entire span of the steel main beam 6 is completely supported by the beam transporting trolley 8, and the beam transporting trolley 8 can transport the entire span of the steel main beam 6 away. During the movement of the beam transporting trolley 8, the height of the foldable liftable pedestal 7 in front of the beam transporting trolley 8 will hinder the passage of the beam transporting trolley 8, so the liftable platform 7 needs to be put down.

In step J, after the erection of the second-span steel girder 6 is completed, the precast concrete bridge deck is hoisted to the second-span steel girder 6 by the tower crane 3 and laid by the bridge erecting machine 9 . Therefore, the installation position of tower crane 3 should be as close to the second span as possible. In this way, there is no need to transfer the precast concrete bridge deck through the first span, and the steel-concrete composite beam of the first span is provided with a beam transport trolley 8 and a foldable liftable pedestal 7, and it is not convenient to transfer the precast concrete bridge deck of other spans. .

After the other span steel main beams 6 are erected, the bridge deck transport trolley is first lifted to the second span steel-concrete composite beam by the tower crane 3, and then the precast concrete bridge deck is lifted to the bridge deck transport trolley by the tower crane 3. The precast concrete bridge deck is transported to the bridge erection machine 9 by the bridge deck transport trolley, and then the bridge deck is laid by the bridge erection machine 9 . After the bridge deck is laid, the steel main beam 6 of the next span must be transported. In order to prevent the bridge deck transport trolley from hindering the passage of the beam transport trolley 8, the bridge deck transport trolley needs to be hoisted away by the tower crane 3, so back and forth.

The foldable liftable pedestal 7 includes two bases 703 that are spaced and parallel along the width direction of the steel-concrete composite beam. The base 703 includes a top steel plate 708 and a bottom steel plate 708. The steel pipes 709 arranged at certain intervals are welded and connected. The top open end of the steel pipes 709 penetrates the top steel plate 708. A screw 701 is inserted into each steel pipe 709, and the screw 701 is threadedly sleeved with an adjusting nut 716. The adjusting nut 716 Supported on the surface of the top steel plate 708 , the top of the screw 701 is fixed with a steel plate 702 , the base 703 is placed on the steel backing plate 704 , and its outer side is rotatably connected to the steel backing plate 704 through hinges 705 .

During use, the screw 701 constitutes a bottom support member for the construction and assembly of the steel main beam 6 , and the steel plate 702 on the top thereof is used to support the steel main beam 6 . During the supporting process, according to the size change of the steel main beam 6, the height of the screw rod 701 needs to be adjusted. The height adjustment of the screw rod 701 is realized by adjusting the nut 716. When the height of the screw rod 701 needs to be lowered, the adjusting nut 716 is rotated to make it relative to the screw rod. When the 701 moves upward, the depth of the screw 701 inserted into the steel pipe 709 is deeper. Since the adjusting nut 716 is always supported on the surface of the top steel plate 708, the height of the screw 701 decreases. When the height of the screw 701 needs to be increased, the reverse operation can be performed. The steel pipe 709 is mainly used for inserting the screw rod 701 to ensure that the screw rod 701 is in a vertical state.

When the beam transporting trolley 8 needs to cross the foldable elevating platform 7, and the beam transporting trolley 8 cannot pass even if the screw rod 701 is lowered to the lowest height, the base 703 and the screw rod 701 can be slowly wound around the hinge 705 is turned to both sides until it is flat on the ground, at which time the beam transporting trolley 8 can pass. During the rotation of the base 703, if the screw rod 701 is located above the unsupported steel main beam 6 or the top of the screw rod 1 is completely close to the bottom of the steel main beam 6, the screw rod 701 can be pulled out from the steel pipe 709, then the screw rod 701 can be directly removed from the steel pipe. After pulling out from 709, rotate the base 703; if there is a supporting steel main beam 6 above the screw 701 and the height of the top of the screw 701 from the bottom of the steel main beam 6 cannot pull the screw 701 out of the steel pipe 709, then directly The screw 701 is turned down together with the base 703 .

The two screws 701 in the same cross section are connected by a screw connection member 706. The screw connection member 706 includes a nut 711 that is threadedly sleeved on the screw rod 701. The side of the nut 711 is fixedly welded with a sleeve 712. The nut 711 and the sleeve 712 are welded and connected at a 90-degree angle. The sleeve 712 is provided with an internal thread. The two sleeves 712 are connected by a connecting screw 713, and the sleeve 712 and the connecting screw 713 are connected by a thread. The screw connection member 706 is provided mainly for enhancing the stability of the screw rod 701 when the foldable elevating platform 7 is in operation. During use, the height of the screw rod 701 can be matched by adjusting the position of the nut 711 . When the screw rod 701 needs to be put down, the connecting screw rod 713 can be unscrewed from the sleeve 712 .

The two bases 703 are connected by a plurality of base connecting pieces 707. The base connecting piece 707 includes a connecting steel plate 714. One end of the connecting steel plate 714 is welded and fixedly connected to the top steel plate 708 of one of the bases 703. One end is provided with a through hole, and is connected to the top steel plate 708 of the other base 703 through the plug 715 passing through the through hole. The base connector 707 is provided to connect the two independent unit bases 703 into one body, thereby enhancing the stability. When the base 703 needs to rotate around the hinge 705, the latch 715 is pulled out, the base 703 on which the connecting steel plate 714 is fixed and welded is rotated first, and then the other base 703 is rotated.

The base 703 also includes an abdominal steel plate 710. The abdominal steel plate 710 is arranged between or outside the adjacent two steel pipes 709, and its side is connected to the steel pipe 709. The top and bottom surfaces of the abdominal steel plate 710 are connected to the top and bottom steel plates 708. Solder connection. The top and bottom steel plates 708 , the steel pipes 709 and the web steel plates 710 are welded to form an integral “I”-shaped base 703 , and the structural strength of the base 703 is ensured by setting the web steel plates 710 .

The steel backing plate 704 is fixed on the bridge deck through expansion bolts 717 .

Since the pedestal is provided with two independent bases 703 , it can be split into two separate foldable and liftable pedestals 7 , which is suitable for common venues with few constraints. The pedestal can be operated and used repeatedly without frequent dismantling and moving, which is more convenient to use.

Claims (9)

1. a full-span in-situ assembling and erecting method for a steel-concrete composite beam in a mountainous area, is characterized in that: specifically comprise the following steps: A. A plurality of temporary piers (1) of steel pipe piles are erected at the position of the first span, a Bailey sheet platform (2) is set up on the temporary piers (1) of steel pipe piles, and a tower crane (3) with corresponding hoisting capacity is arranged beside the first span. ); B. Permanent supports (4) are arranged on the cover beams at both ends of the beret platform (2), and a certain number of liftable pedestals are arranged on the beret platform (2) between the permanent supports (4). (5); C. Set the initial height of each liftable pedestal (5) according to the pre-camber line, and use the tower crane (3) to assemble the steel main beam (6) above the liftable pedestal (5); D. After the steel main beam (6) is assembled and before the bridge deck is installed, calculate the deflection value of the steel main beam (6) according to the theory, lower the height of each liftable pedestal (5) in advance, and then use the tower crane (3) to hoist the precast concrete The bridge deck, after the installation of the bridge deck is completed, the whole span steel main beam (6) is supported by the liftable pedestal (5); E. After the bridge deck on the steel main beam (6) is installed, weld the longitudinal and transverse steel bars of the adjacent bridge decks to make all the bridge decks of the whole span form a whole; F. After the welding of the steel bars is completed, the concrete at the notch of the shear nails is reserved for the cast-in-place bridge deck, and the bridge deck is consolidated on the steel main beam (6) to form the first span steel-concrete composite beam; G. Arrange a foldable liftable pedestal (7) on the assembled first-span steel-concrete composite beam; H. A beam transporting trolley (8) is arranged at both ends of the steel-concrete composite beam of the first span, and the second-span steel main beam (6) is assembled on the foldable liftable pedestal (7); 1. After the second span steel main beam (6) is assembled, lower the height of the foldable elevating pedestal (7) and lay it down on the bridge deck, and the whole span steel main beam is transported by the beam transport trolley (8). (6) transport to the bottom of the bridge erection machine (9), and realize the erection of the whole span steel main beam (6) through the bridge erection machine (9); J. After the steel main beam (6) of the second span is erected, the bridge deck is installed, and at the same time, the beam transporting trolley (8) is moved back to the steel-concrete composite beam of the first span, ready to assemble the steel main beam (6) of the next span. The bridge crane (9) is moved forward to prepare the next span steel main beam (6); K. Repeat steps H to J to realize the erection and installation of a steel-concrete composite beam; L. Remove the liftable pedestal (5), and pour the whole wet joint at one time. 2. The in-situ assembling and erecting method for the entire span of a steel-concrete composite beam in a mountainous area according to claim 1, characterized in that: the bridge erecting machine (9) adopts a widening bridge erecting machine. 3. The in-situ assembling and erecting method for the entire span of a steel-concrete composite beam in a mountainous area according to claim 1, characterized in that: in the step H, on the beam transporting trolley (8) and the foldable liftable pedestal (7) Assemble other span steel main beams (6). 4. The whole span in-situ assembling and erecting method of a steel-concrete composite beam in a mountainous area according to claim 1, is characterized in that: in step J, after the second span steel main beam (6) is erected, the prefabricated steel beam (6) is erected by the tower crane (3). The concrete bridge deck is hoisted to the second span steel main beam (6) and laid by the bridge erection machine (9); after the other span steel main beams (6) are erected, the bridge deck transport trolley is lifted by the tower crane (3). It is transported to the steel-concrete composite beam of the second span, and then the precast concrete bridge deck is hoisted by the tower crane (3) to the bridge deck transport trolley, and the bridge deck transport trolley transports the precast concrete bridge deck to the bridge erecting machine (9). , the bridge deck is laid by the bridge erecting machine (9), and after the bridge deck is laid, the bridge deck transport trolley is hoisted away by the tower crane (3). 5. The full-span in-situ assembling and erecting method for a steel-concrete composite beam in a mountainous area according to claim 1, wherein the foldable liftable pedestal (7) includes spaced and parallel pedestals along the width direction of the steel-concrete composite beam. 2 bases (703), the base (703) includes top and bottom steel plates (708), the top and bottom steel plates (708) are connected by a plurality of steel pipes (709) arranged at intervals, each steel pipe (709) A screw (701) is inserted into the screw (701), an adjusting nut (716) is threadedly sleeved on the screw (701), a steel plate (702) is fixed on the top of the screw (701), and the base (703) is placed on the steel backing plate (704). ), its outer side is rotatably connected with the steel backing plate (704) through a hinge (705). 6. The in-situ assembling and erecting method for the entire span of a steel-concrete composite beam in a mountainous area according to claim 5, wherein the two screws (701) in the same cross section are connected by screw connection members (706), so that the The screw connecting member (706) includes a nut (711) that is threadedly sleeved on the screw (701), a sleeve (712) is fixedly connected to the side of the nut (711), and a connecting screw is connected between the two sleeves (712). (713) to connect. 7. The in-situ assembly and erection method for the entire span of a steel-concrete composite beam in a mountainous area according to claim 5, wherein the two bases (703) are connected through a plurality of base connectors (707), and the bases The connecting piece (707) includes a connecting steel plate (714), one end of the connecting steel plate (714) is fixedly connected to the top steel plate (708) of one of the bases (703), and the other end of the connecting steel plate (714) is connected to the other base through a latch (715). (703) top steel plate (708) for connection. 8. The in-situ assembly and erection method for the entire span of a steel-concrete composite beam in a mountainous area according to claim 5, wherein the base (703) further comprises an abdominal steel plate (710), and the abdominal steel plate (710) is arranged on the opposite side. Between or outside the adjacent two steel pipes (709), the side surfaces are connected with the steel pipes (709), and the top and bottom surfaces are connected with the top and bottom steel plates (708). 9 . The in-situ assembly and erection method for the entire span of a steel-concrete composite beam in mountainous areas according to claim 5 , wherein the steel backing plate ( 704 ) is fixed on the surface of the steel-concrete composite beam through expansion bolts ( 717 ). 10 .

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