Method for constructing long-span steel-concrete composite beams based on bridge erection machine

Abstract

The present invention discloses a method for constructing a large-span steel-concrete composite beam based on a bridge erection machine, including ① completing the construction of the lower pier column of the target bridge and prefabricating the steel beam segment ② allowing the bridge erection machine to move to the first hole of the target bridge, installing the steel beam segment of the first span, and connecting them together ③ allowing the bridge erection machine to move to the second hole of the target bridge, installing the steel beam segment of the second span, and connecting it with the steel beam segment of the first pier top ④ installing the prefabricated bridge deck in the mid-span area of ​​the first and second holes of the target bridge, pouring wet joint concrete ⑤ adjusting the rear legs of the bridge erection machine so that it is located in the mid-span area of ​​the first and second holes, then installing the prefabricated bridge deck in the pier top area and pouring wet joint concrete ⑥ repeating steps 2 to 5 to complete the construction of the entire bridge. The present invention is fast in construction and economical, and can reduce the risk of cracking of the bridge deck in the negative bending moment area. It is very suitable for building large-span steel-concrete composite beam bridges in plain areas, across deep valleys in mountainous areas, and across rivers, and has broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of steel-concrete composite beam construction, in particular to a method for constructing a large-span steel-concrete composite beam based on a bridge erecting machine. Background Art

[0002] Steel-concrete composite beams have a series of advantages such as light structure, large span capacity, and fast construction speed. They can meet the construction requirements of urban viaducts and long bridges across rivers and seas to the greatest extent, and are increasingly widely used in modern bridge structures. Small and medium-span steel-concrete composite beams (span <30m) have the characteristics of high standardization, easy processing, light structure weight, and convenient erection. They have been used on a large scale in provinces such as Hebei, Gansu, and Yunnan. However, large-span steel-concrete composite beams (span ≥30 meters) are generally hoisted or pushed by bracket segments due to the influence of equipment technology and construction technology, which affects their large-scale application.

[0003] Based on this, Chinese patents ZL 201711333897.X on the method of constructing steel-concrete composite beams using vertical cables, ZL 201721738138.7 on the cable device for the whole span construction of steel-concrete composite beams, and ZL 201910699994.3 on the construction method of two-span continuous steel-concrete composite bridges using back-cable bridge erecting machines have proposed a construction method of erecting whole-span steel beams using bridge erecting machines, which has a series of advantages such as high degree of prefabrication and assembly and high construction efficiency. The above construction methods are well applicable to steel-concrete composite beams with a span of 30-120m, but when the span of the steel-concrete composite beam increases to 120-150m, the following problems will be faced: 1) The scale of the bridge erecting machine for erecting the whole-span steel beam is very large, and the economic efficiency of the construction plan becomes worse; 2) The dead weight and geometric dimensions of the whole-span steel beam are very large, and the manufacturing, transportation and installation processes of the whole-span steel beam become very difficult, which is not conducive to construction. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for constructing a large-span steel-concrete composite beam based on a bridge erection machine with convenient construction and low cost. Specifically, the following technical solutions can be adopted:

[0005] The steel-concrete composite beam comprises a mid-span steel beam segment and a pier top steel beam segment, the mid-span steel beam segment and the pier top steel beam segment are staggered and connected together, a prefabricated bridge deck is arranged above the mid-span steel beam segment and the pier top steel beam segment, and wet joint concrete is poured between the prefabricated bridge decks;

[0006] The construction steps of the steel-concrete composite beam include:

[0007] The first step is to complete the construction of the lower piers of the target bridge. At the same time, the pier top steel beam segments and the mid-span steel beam segments are prefabricated in the factory.

[0008] The second step is to move the bridge erection machine to the first hole of the target bridge, and install the first pier top steel beam segment to the pier top position of the first hole, install the first span middle steel beam segment to the span middle position of the first hole, and connect the first span middle steel beam segment and the first pier top steel beam segment together;

[0009] The third step is to move the bridge erection machine to the second hole of the target bridge, and install the second pier top steel beam segment to the pier top position of the second hole, install the second span middle steel beam segment to the span middle position of the second hole, and connect the second span middle steel beam segment with the first pier top steel beam segment and the second pier top steel beam segment;

[0010] Step 4: Install the precast bridge deck in the mid-span area of ​​the first and second spans of the target bridge and pour wet joint concrete;

[0011] Step 5: adjust the rear legs of the bridge erector so that they are located in the mid-span area of ​​the first and second spans, then install the precast bridge deck in the pier top area and pour wet joint concrete;

[0012] Step 6. Repeat steps 2 to 5 to complete the construction of the entire bridge.

[0013] Furthermore, the mid-span steel beam segments and the pier top steel beam segments are both transported by beam transport vehicles, and the beams are fed from the tail of the bridge erecting machine.

[0014] Preferably, the mid-span steel beam segment and the pier top steel beam segment are both transported on the beam transport vehicle by beam-on-beam transport.

[0015] Furthermore, the steel-concrete composite beam is a constant-height beam or a variable-height beam with a span of 80-150m.

[0016] Preferably, the length ratio of the mid-span steel beam segment and the pier top steel beam segment is 2:1.

[0017] The method for constructing large-span steel-concrete composite beams based on a bridge erection machine provided by the present invention has the advantages of fast construction and good economy, and can reduce the risk of bridge deck cracking in negative bending moment areas. It is very suitable for building large-span steel-concrete composite beam bridges on overpasses in plain areas, across deep valleys in mountainous areas, and across rivers, and has broad application prospects.

[0018] Compared with the existing construction method, the advantages of the present invention are specifically embodied in:

[0019] 1) Compared with the whole-hole erection method, the bridge erection machine used in the present invention is small in scale, low in equipment cost, and good in economy;

[0020] 2) Compared with the whole-hole erection method, the steel beam used in the present invention has a light weight, small geometric size, and is more convenient to manufacture, transport and install;

[0021] 3) After the mid-span bridge deck is installed and the wet joint concrete reaches the design strength, adjust the two rear legs of the bridge erection machine to place weight on top of the two adjacent bridge decks, and then install the prefabricated bridge deck in the pier top area. This construction can apply pre-pressure to the bridge deck in the pier top area and reduce the risk of cracking of the bridge deck. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figures 1 to 8 It is a schematic diagram of the construction steps of the present invention.

[0023] Fig. 9 It is a schematic diagram of the cross-sectional structure of the left steel beam erected by the bridge erecting machine of the present invention. DETAILED DESCRIPTION

[0024] The method for constructing a large-span steel-concrete composite beam based on a bridge-building machine described in the present invention is suitable for steel-concrete composite beams with a span of 80-150m. The above-mentioned steel-concrete composite beams can be equal-height beams or variable-height beams. However, whether they are equal-height beams or variable-height beams, they all include mid-span steel beam segments and pier top steel beam segments that are staggered and connected together, and prefabricated bridge panels are arranged above the mid-span steel beam segments and the pier top steel beam segments, and wet joint concrete is poured between the prefabricated bridge panels.

[0025] In conjunction with the accompanying drawings, a steel-concrete continuous composite beam with a span arrangement of (80+5×120+80) m and a bridge width of 16.5 m is taken as an example to describe in detail the steel-concrete composite beam construction method of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific construction process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0026] The method for constructing a large-span steel-concrete composite beam based on a bridge erecting machine of the present invention comprises the following steps:

[0027] The first step is to complete the construction of the lower piers of the target bridge, and at the same time, prefabricate the pier top steel beam segments and the mid-span steel beam segments in the factory. In order to achieve mass production and save costs, the length of the mid-span steel beam segments in this embodiment is 80m except for the first hole, which is 60m, and the length of the pier top steel beam segments is 40m, with a length ratio of 2:1. In addition, the process parameters such as the length of the prefabricated pier top steel beam segments and the mid-span steel beam segments can be determined according to the specific design plan of the bridge.

[0028] The second step is to move the bridge-erecting machine to the first hole of the target bridge, and use the bridge-erecting machine to install the first pier top steel beam segment to the pier top position of the first hole, install the first span middle steel beam segment to the span middle position of the first hole, and connect the first span middle steel beam segment and the first pier top steel beam segment together.

[0029] Specifically, it includes:

[0030] S2.1, the bridge erecting machine 1 moves to the first span of the target bridge, and at the same time, the beam transport vehicle 2 transports the first pier top steel beam segment 3 to the tail of the bridge erecting machine 1 by beam-on-beam transport (see Figure 1 );

[0031] S2.2, the bridge erecting machine 1 installs the first pier top steel beam segment 3 to the pier top position of the first hole, and at the same time the beam transport vehicle 2 transports the first span steel beam segment 4 to the tail of the bridge erecting machine 1 for beam feeding (see Figure 2 );

[0032] S2.3, the bridge erection machine 1 installs the first span steel beam segment 4 to the mid-span position of the first hole (see Fig. 9 ), and connect the first span steel beam segment 4 with the first pier top steel beam segment 3; at the same time, the beam transport vehicle 2 transports the second pier top steel beam segment 5 to the tail of the bridge erecting machine 1 for beam feeding (see Figure 3 );

[0033] The third step is to move the bridge erection machine to the second hole of the target bridge, and install the second pier top steel beam segment to the pier top position of the second hole, install the second span middle steel beam segment to the span middle position of the second hole, and connect the second span middle steel beam segment with the first pier top steel beam segment and the second pier top steel beam segment;

[0034] Specifically, it includes:

[0035] S3.1, the bridge erecting machine 1 moves to the second hole, installs the second pier top steel beam segment 5 to the pier top position of the second hole, and at the same time, the beam transport vehicle 2 transports the second span steel beam segment 6 to the tail of the bridge erecting machine 1 for feeding beams (see Figure 4 );

[0036] S3.2, install the second span middle steel beam segment 6 to the middle span position of the second hole, and then connect the second span middle steel beam segment 6 with the first pier top steel beam segment 3 and the second pier top steel beam segment 5 (see Figure 5 );

[0037] The fourth step is to install the precast bridge deck 7 with a length of 60m in the middle span area of ​​the first hole and 60m in the middle span area of ​​the second hole, and pour wet joint concrete (see Figure 6 );

[0038] Step 5: After the concrete reaches the design strength, adjust the 3# and 4# rear legs of the bridge erection machine 1 so that they are located above the bridge deck in the mid-span area of ​​the first and second spans, respectively, and then install the prefabricated bridge deck in the pier top area and pour wet joint concrete;

[0039] Adjust the rear legs of the bridge erector so that they are located in the mid-span area of ​​the first and second spans, then install the precast bridge deck 8 in the pier top area and pour wet joint concrete (see Figure 7 );

[0040] Step 6: Repeat steps 2 to 5 to complete the construction of the entire bridge (see Figure 8 ).

[0041] Table 1 shows a comparison of the relevant parameters of the construction method for erecting a full-hole steel beam by the present invention and the traditional bridge erection machine.

[0042] Table 1 Comparison of construction parameters

[0043]

[0044] In summary, the present invention can overcome the shortcomings of poor economy and inconvenience in the construction of large-span full-hole steel beams erected by bridge-erecting machines, and divides the large-span steel beams into segments for prefabrication and installation. It not only retains the advantages of high degree of prefabrication and assembly of steel-concrete composite beams erected by bridge-erecting machines for full-hole construction and is not restricted by the environment under the bridge, but also has the advantages of fast construction, low cost of bridge-erecting machine equipment, good stress-bearing performance of the bridge deck on the pier top of the steel-concrete composite beam, etc., and has broad application prospects in the erection of large-span steel-concrete composite beams.

[0045] It should be noted that, in the description of the present invention, terms indicating orientation or positional relationships, such as "front", "rear", "left", "right", "vertical", "horizontal", "inside", "outside", etc., are based on the orientation or positional relationships shown in the drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

Claims

1. A method for constructing a large-span steel-concrete composite beam based on a bridge erection machine, characterized in that: The steel-concrete composite beam comprises a mid-span steel beam segment and a pier top steel beam segment, the mid-span steel beam segment and the pier top steel beam segment are staggered and connected together, a prefabricated bridge deck is arranged above the mid-span steel beam segment and the pier top steel beam segment, and wet joint concrete is poured between the prefabricated bridge decks; The construction steps of the steel-concrete composite beam include: The first step is to complete the construction of the lower piers of the target bridge. At the same time, the pier top steel beam segments and the mid-span steel beam segments are prefabricated in the factory. The second step is to move the bridge erection machine to the first hole of the target bridge, and install the first pier top steel beam segment to the pier top position of the first hole, install the first span middle steel beam segment to the span middle position of the first hole, and connect the first span middle steel beam segment and the first pier top steel beam segment together; The third step is to move the bridge erection machine to the second hole of the target bridge, and install the second pier top steel beam segment to the pier top position of the second hole, install the second span middle steel beam segment to the span middle position of the second hole, and connect the second span middle steel beam segment with the first pier top steel beam segment and the second pier top steel beam segment; Step 4: Install the precast bridge deck in the mid-span area of ​​the first and second spans of the target bridge and pour wet joint concrete; Step 5: adjust the rear legs of the bridge erector so that they are located in the mid-span area of ​​the first and second spans, then install the precast bridge deck in the pier top area and pour wet joint concrete; Step 6. Repeat steps 2 to 5 to complete the construction of the entire bridge.

2. The method for constructing a large-span steel-concrete composite beam based on a bridge erection machine according to claim 1, characterized in that: The mid-span steel beam segments and the pier top steel beam segments are both transported by beam transport vehicles, and the beams are fed by the tail of the bridge erecting machine.

3. The method for constructing a large-span steel-concrete composite beam based on a bridge erecting machine according to claim 2, characterized in that: The mid-span steel beam segment and the pier top steel beam segment are both transported on the beam transport vehicle using a beam-on-beam transport method.

4. The method for constructing a large-span steel-concrete composite beam based on a bridge erection machine according to claim 1, characterized in that: The steel-concrete composite beam is a constant-height beam or a variable-height beam with a span of 80-150m.

5. The method for constructing a large-span steel-concrete composite beam based on a bridge erecting machine according to claim 1, characterized in that: The length ratio of the mid-span steel beam segment and the pier top steel beam segment is 2:1.

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