Joining method for existing twin concrete box girder bridge

Abstract

Disclosed in the present invention is a joining method for an existing twin concrete box girder bridge, comprising the following steps: firstly, chiseling away concrete at the outer ends of deck slab cantilevers of a twin bridge, and retaining reinforcing steel bars at the outer ends of the deck slab cantilevers; manufacturing a joining steel support, the joining steel support comprising a support plate, a top panel and a bottom panel; mounting a plurality of rows of pre-embedded reinforcing steel bars in the middle of the top panel; forming a plurality of rows of chemical anchor bolt mounting holes on each of two sides of the top panel; implanting a chemical anchor bolt into each of the deck slab cantilevers and webs of the twin bridge; hoisting the joining steel support, inserting the chemical anchor bolts on the twin concrete box girder bridge into the corresponding chemical anchor bolt mounting holes in the joining steel support on a one-to-one basis, and then mounting a fastening nut on each chemical anchor bolt, such that the top panel of the joining steel support is closely attached to the bottom surfaces of the deck slab cantilevers and the outer side surfaces of the webs of the twin bridge; mounting a pouring formwork and binding a reinforcing steel bar mesh; and pouring concrete into the pouring formwork to form a joining strip. The present invention achieves both convenient construction and high construction efficiency.

Description

Splicing method for existing double-width concrete box girder bridge TECHNICAL FIELD

[0001] The present application relates to a splicing method for an existing double-width concrete box girder bridge. BACKGROUND

[0002] With the rapid development of China's social economy, the highway traffic volume is increasing, and the phenomenon of heavy overload is serious, which brings greater challenges to the transportation construction industry. Due to the particularity of the terrain environment, at present, many highway bridge projects are greatly reduced in traffic capacity due to low design standards, material aging, insufficient lane width and other problems. Rebuilding the bridge has high economic cost and may cause traffic interruption and other problems. In order to meet the increasing traffic volume, the bridge project can be improved and expanded, and the use performance can be improved by widening the original bridge deck. The double-width bridge is composed of two bridges side by side, and each bridge usually allows vehicles to travel in one direction, which is suitable for scenes with large multi-lane traffic volume. Restricted by the overall layout of the road, there is often a wide gap between the double-width bridges. The current bridge splicing method can make full use of the existing box girder structure, and under the action of vehicle load, the bridge deck forms a composite beam stress system, which has good stress performance, is convenient to construct, and has high construction efficiency, but is less used in bridge widening structures. With the rapid development of China's social economy, the road network traffic volume is increasing year by year, which makes it difficult for a large number of early built roads and bridges to meet the current traffic operation requirements, so more and more reconstruction and expansion projects appear. Under such conditions, it is necessary to widen (widen) and reinforce the original bridge, that is, on the basis of ensuring the safe operation of the bridge, effectively utilizing the structure of the original bridge, so that the widened (widen) bridge meets the current technical specifications and also meets the existing functional requirements. After investigation and analysis, under the premise of meeting the existing technical requirements and functional requirements, the old bridge can be widened (widen) and reconstructed, which can greatly save the cost. Therefore, considering the economy and practicability and other factors, the old bridge that does not meet the functional requirements needs to be widened (widen), so that the old bridge can be fully utilized and fully play its economic value.

[0003] The widening project is a high-technology project in the reconstruction project, and the key technical problems include the widening method (different widening methods for different bridge types, selection of widening scheme), bridge deck cracking (stress analysis of the connecting joint of the new bridge and the old bridge), and whether the bearing capacity of the upper and lower structures of the bridge is sufficient. These technical problems are directly related to the safety and stability of the bridge. Therefore, the present application has important significance.

[0004] At present, the splicing technology of old and new bridges is common in China, and the splicing of double-width cast-in-place box girder is extremely rare. Because the cantilever plate of cast-in-place box girder (especially rigid frame bridge) is large, the middle division of double-width bridge is wide, and the deck plate span is large after splicing. This makes the technical problems such as concrete cracking at the splicing belt position, large change of existing cantilever stress mode after splicing, great influence of splicing reconstruction on existing deck plate, existing road camber after splicing, and decrease of bridge bearing capacity after reconstruction particularly prominent. SUMMARY

[0005] The purpose of the present application is to overcome the defects of the prior art and provide a splicing method for existing double-width concrete box girder bridge, which uses a splicing steel support as a splicing piece of the double-width existing box girder bridge. Under the action of the load of the vehicle, the splicing steel support and the deck plate of the double-width existing box girder bridge locally form a composite beam stress system, which has good stress performance, is convenient to construct, and has high construction efficiency.

[0006] The purpose of the present application is achieved by a splicing method for existing double-width concrete box girder bridge, comprising the following steps:

[0007] Step one, the concrete at the cantilevered outer end of the deck plate of the double-width concrete box girder bridge is chiseled off first, so that a splicing belt is formed between the cantilevered outer ends of the deck plate of the double-width concrete box girder bridge after chiseling, and the steel bars at the cantilevered outer ends of the deck plate of the double-width concrete box girder bridge are retained, so that the thickness of the cantilevered outer ends of the deck plate of the double-width concrete box girder bridge reaches the requirement of bearing capacity, and the surface of the cantilevered outer ends of the deck plate of the double-width concrete box girder bridge after chiseling is polished;

[0008] Step two, the splicing steel support is made according to the actual situation of the bridge body and the design requirement. The splicing steel support comprises a support plate, top face plates fixed on the top face and both sides of the support plate, and a bottom plate fixed on the bottom face of the support plate. The middle part of the top face of the support plate is a horizontal face, and the length of the middle part of the top face of the support plate is adapted to the width of the splicing belt. The two sides of the top face of the support plate are inclined faces adapted to the bottom face of the cantilever of the double-width concrete box girder bridge. The two side faces of the support plate are inclined faces adapted to the outer side face of the web of the double-width concrete box girder bridge. Each of the two side faces and the two sides of the top face is connected by a circular face. The circular face is adapted to the connecting face between the root bottom face of the cantilever of the single-width concrete box girder bridge and the outer side face of the web. The top face plate is attached to the bottom face of the cantilever of the double-width concrete bridge and the outer side face of the web of the double-width concrete bridge. The middle part of the top face plate is provided with a plurality of rows of pre-embedded steel bar mounting holes. Each row of pre-embedded steel bar mounting holes has two pre-embedded steel bar mounting holes corresponding to the front side and the rear side of the support plate, and each pre-embedded steel bar mounting hole is fixed with a pre-embedded steel bar. Each of the two sides of the top face plate is provided with a plurality of rows of chemical anchor mounting holes. Each row of chemical anchor mounting holes has two chemical anchor mounting holes corresponding to the front side and the rear side of the support plate.

[0009] Step three, first measure the chemical anchor installation position corresponding to the chemical anchor installation hole on the splicing steel support on the bridge deck slab cantilever and web of the double-lane concrete box girder bridge, and mark and punch the chemical anchor installation position on the bridge deck slab cantilever and web of the double-lane concrete box girder bridge, and then implant a chemical anchor at each chemical anchor installation position on the bridge deck slab cantilever and web of the double-lane concrete box girder bridge;

[0010] Step four, when the chemical anchors on the bridge deck slab cantilever and web of the double-lane concrete box girder bridge are solidified and reach a certain strength, hoist the splicing steel support, so that the splicing steel support is located below the bridge deck slab cantilevers of the double-lane concrete box girder bridge, and the chemical anchors on the double-lane concrete box girder bridge are inserted into the chemical anchor installation holes on the splicing steel support one by one, and then a fastening nut is installed on each chemical anchor, so that the splicing steel support is hung by the chemical anchors, by applying a pre-tightening force to the fastening nut, the top panel of the splicing steel support is attached to the bottom surface of the bridge deck slab cantilever of the double-lane concrete bridge and the outer lateral surface of the web of the double-lane concrete bridge, and a plurality of rows of pre-embedded steel bars on the splicing steel support are inserted between the exposed bridge deck slab steel bars of the double-lane concrete box girder bridge;

[0011] Step five, install a pouring form at the middle part of the top panel of the splicing steel support between the outer ends of the bridge deck slab cantilevers of the double-lane concrete box girder bridge, and then bind a steel mesh on the exposed bridge deck slab steel bars of the double-lane concrete box girder bridge and the pre-embedded steel bars on the splicing steel support in the pouring form;

[0012] Step six, pour concrete into the pouring form to form a splicing band, and after the cast-in-place splicing band cools for 28 days, the pouring form is removed, and the construction is completed.

[0013] The above-mentioned splicing method of the existing double-lane concrete box girder bridge, wherein when step two is performed, a plurality of reinforcing rib plates are arranged between the top two side surfaces of the support plate and the bottom surface of the top panel, and a plurality of reinforcing rib plates are also arranged between the bottom two side surfaces of the support plate and the top surface of the bottom panel.

[0014] The above-mentioned splicing method of the existing double-lane concrete box girder bridge, wherein when step two is performed, a plurality of lightening holes are formed on the support plate.

[0015] The above-mentioned splicing method of the existing double-lane concrete box girder bridge, wherein when step five is performed, the steel mesh is formed by binding a plurality of transverse steel bars and a plurality of longitudinal steel bars.

[0016] The splicing method of the existing double-lane concrete box girder bridge of the present application has the following characteristics:

[0017] 1. The spliced steel support is used as a splicing piece of the existing double-width concrete box girder bridge, and the splicing piece is not removed, and the lightening holes are arranged in the spliced steel support, so that the stress performance of the splicing piece is superior, the self weight of the splicing piece is small, the construction is convenient, and the interference to the surrounding environment is small.

[0018] 2. The splicing steel support is connected with the existing double-width concrete box girder bridge through chemical anchors, so that the splicing belt has shear resistance and lifting resistance.

[0019] 3. The splicing steel support is connected with the cast-in-place splicing belt through embedded steel bars, so that the construction is more convenient, the installation of the splicing piece is avoided, and the construction efficiency is high.

[0020] 4. The reinforcing rib plate is fused in the structure of the splicing steel support, so that the strength and rigidity of the splicing steel support are further enhanced, and the bearing capacity of the splicing steel support is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 is a perspective view of the existing double-width concrete box girder bridge before splicing according to the present application;

[0022] Fig. 2 is a structural schematic view after step one of the splicing method according to the present application;

[0023] Fig. 3 is a perspective view of the splicing steel support made when step two of the splicing method according to the present application is performed;

[0024] Fig. 4 is a perspective view when step four of the splicing method according to the present application is performed;

[0025] Fig. 5 is a perspective view after step four of the splicing method according to the present application is performed;

[0026] Fig. 6 is a perspective view after step five of the splicing method according to the present application is performed;

[0027] Fig. 7 is a perspective view after step six of the splicing method according to the present application is performed. DETAILED DESCRIPTION

[0028] The present application will be further described below with reference to the accompanying drawings.

[0029] First, refer to Figs. 1 to 7, the splicing method of the existing double-width concrete box girder bridge according to the present application includes the following steps:

[0030] Step one, first use professional tools to remove the concrete of the bridge deck slab cantilevered outer end of the left existing concrete box girder bridge 1 and the concrete of the bridge deck slab cantilevered outer end of the right existing concrete box girder bridge 3, so that the left existing concrete box girder bridge 1 and the right existing concrete box girder bridge 3 form a splicing zone 10, and the steel bars 2 of the left existing concrete box girder bridge 1 and the right existing concrete box girder bridge 3 are reserved (see FIG. 2), so that the thickness of the left existing concrete box girder bridge 1 and the thickness of the right existing concrete box girder bridge 3 meet the requirements of bearing capacity, and the surfaces of the left existing concrete box girder bridge 1 and the right existing concrete box girder bridge 3 are polished to ensure that the surfaces are smooth and flat;

[0031] Step two, according to the actual situation and design requirements of the bridge body, a splicing steel support 4 is made, which includes a support plate 40, a top plate 41 fixed to the top surface and both sides of the support plate 40, and a bottom plate 42 fixed to the bottom surface of the support plate 40; the middle part of the top surface of the support plate 40 is a horizontal surface, and the length of the middle part of the top surface of the support plate 40 is adapted to the width of the splicing zone 10, the two sides of the top surface of the support plate 40 are inclined surfaces adapted to the bottom surfaces of the bridge deck slab cantilevers of the left existing concrete box girder bridge 1 and the right existing concrete box girder bridge 3, the two side surfaces of the support plate 40 are inclined surfaces adapted to the outer surfaces of the webs of the left existing concrete box girder bridge 1 and the right existing concrete box girder bridge 3, the two side surfaces of the support plate 40 are respectively connected to the top surface through arc surfaces, the arc surfaces are adapted to the connecting surfaces between the root bottom surfaces of the bridge deck slab cantilevers and the outer surfaces of the webs of the single concrete box girder bridge, so that the top plate 41 is attached to the bottom surfaces and the outer surfaces of the webs of the bridge deck slab cantilevers of the left existing concrete box girder bridge 1 and the right existing concrete box girder bridge 3; a plurality of lightening holes 400 are formed in the support plate 40; a plurality of reinforcing rib plates 43 are arranged at intervals between the top side surfaces of the support plate 40 and the bottom surface of the top plate 41, and a plurality of reinforcing rib plates 43 are also arranged at intervals between the bottom side surfaces of the support plate 40 and the top surface of the bottom plate 42; a plurality of rows of pre-embedded steel bar installation holes are formed in the middle part of the top plate 41, the number of each row of pre-embedded steel bar installation holes is two and corresponds to the front side and the rear side of the support plate 40 respectively, and a pre-embedded steel bar 5 is fixedly installed in each pre-embedded steel bar installation hole (see FIG. 3); a plurality of rows of chemical anchor bolt installation holes are formed in the two sides of the top plate 41, the number of each row of chemical anchor bolt installation holes is two and corresponds to the front side and the rear side of the support plate 40 respectively;

[0032] Step three, first measure the left existing concrete box girder bridge 1 of the bridge deck cantilever and web and the right existing concrete box girder bridge 3 of the bridge deck cantilever and web and the corresponding chemical anchor bolt installation hole on the steel support 4 on the installation position of the chemical anchor bolt, and mark and punch the chemical anchor bolt installation position on the left existing concrete box girder bridge 1 of the bridge deck cantilever and web and the right existing concrete box girder bridge 3 of the bridge deck cantilever and web, and then implant a chemical anchor bolt 6 in each chemical anchor bolt installation position on the left existing concrete box girder bridge 1 of the bridge deck cantilever and web and the right existing concrete box girder bridge 3 of the bridge deck cantilever and web;

[0033] Step four, when the chemical anchor bolt on the left existing concrete box girder bridge 1 of the bridge deck cantilever and web and the right existing concrete box girder bridge 3 of the bridge deck cantilever and web is solidified and reaches a certain strength, a plurality of steel supports 4 are hoisted in turn, so that the plurality of steel supports 4 are located at the lower part between the left existing concrete box girder bridge 1 of the bridge deck cantilever and the right existing concrete box girder bridge 3 of the bridge deck cantilever, and the chemical anchor bolt 6 on the left existing concrete box girder bridge 1 and the chemical anchor bolt 6 on the right existing concrete box girder bridge 3 are inserted into the chemical anchor bolt installation hole on the steel support 4 in one-to-one correspondence, and then a fastening nut 7 is installed on each chemical anchor bolt 6 (see Figure 4), so that the plurality of steel supports 4 are hung by the chemical anchor bolt 6, by applying a pre-tightening force to the fastening nut 7, the top panel 41 of the steel support 4 is attached to the bottom surface of the bridge deck cantilever and the outer side surface of the web of the left existing concrete box girder bridge 1 and the right existing concrete box girder bridge 3, and a plurality of rows of embedded steel bars 5 on the steel support 4 are inserted between the exposed bridge deck steel bars 2 of the left existing concrete box girder bridge 1 and the exposed bridge deck steel bars 2 of the right existing concrete box girder bridge 3 (see Figure 5);

[0034] Step five, a pouring formwork 8 is installed on the middle part of the top panel 41 of the steel support 4 between the outer end of the bridge deck cantilever of the left existing concrete box girder bridge 1 and the outer end of the bridge deck cantilever of the right existing concrete box girder bridge 3, and a steel mesh 9 is bound on the exposed bridge deck steel bars 2 of the left existing concrete box girder bridge 1 and the exposed bridge deck steel bars 2 of the right existing concrete box girder bridge 3 and the embedded steel bars 5 on the steel support 4 in the pouring formwork 8; the steel mesh 9 is formed by binding a plurality of transverse steel bars and a plurality of longitudinal steel bars (see Figure 6);

[0035] Step six, concrete is poured into the pouring formwork 8 to form a spliced strip 10 (see Figure 7); during pouring, the construction personnel need to strictly follow the construction process to ensure that the spliced strip 10 has good integrity and stability. After the cast-in-place spliced strip 10 cools for 28 days, the pouring formwork 7 is removed, and the construction is completed.

[0036] The splicing method of the double-width concrete box girder bridge of the present application connects the left-width existing concrete box girder bridge 1 and the right-width existing concrete box girder bridge 3 closely through a plurality of splicing steel supports 4; wherein the splicing steel support is connected with the left-width existing concrete box girder bridge 1 and the right-width existing concrete box girder bridge 3 through chemical anchor bolts 6, and is connected with the cast-in-place splicing belt 10 through embedded steel bars 5, the chemical anchor bolts 6 and the embedded steel bars 5 provide certain shear resistance for the splicing belt 10 between the left-width existing concrete box girder bridge 1 and the right-width existing concrete box girder bridge 3; a certain pressure is generated on the splicing steel support 4 by applying pre-tightening force through the fastening nuts 7; the structure rigidity and strength of the splicing steel support 4 are enhanced, and the bearing capacity of the splicing steel support 4 is improved by setting reinforcing rib plates 43 on the splicing steel support 4; the self-weight of the splicing steel support 4 is reduced by opening lightening holes on the support plates 40 of the splicing steel support 4, so that the construction is more convenient.

[0037] The above examples are only for illustrating the present application, and are not a limitation of the present application. Those skilled in the art can make various transformations or modifications without departing from the spirit and scope of the present application. Therefore, all equivalent technical solutions should belong to the scope of the present application, which is limited by the claims.

Claims

1. A method of splicing an existing dual-width concrete box girder bridge, characterized by, The splicing method comprises the following steps: Step one, first chisel the concrete at the cantilevered outer end of the deck slab of the double-lane concrete box girder bridge, so as to form a splicing zone between the cantilevered outer ends of the deck slab of the double-lane concrete box girder bridge after chiseling, and the steel bars at the cantilevered outer ends of the deck slab of the double-lane concrete box girder bridge are reserved, so that the thickness of the cantilevered outer ends of the deck slab of the double-lane concrete box girder bridge meets the requirement of bearing capacity, and the surface of the cantilevered outer ends of the deck slab of the double-lane concrete box girder bridge after chiseling is polished; Step two, according to the actual situation of the bridge body and the design requirement, a splicing steel support is prepared, the splicing steel support comprises a support plate, a top plate fixed to the top surface and the two side surfaces of the support plate and a bottom plate fixed to the bottom surface of the support plate; the middle part of the top surface of the support plate is a horizontal surface, and the length of the middle part of the top surface of the support plate is adapted to the width of the splicing zone, the two sides of the top surface of the support plate are inclined surfaces adapted to the bottom surface of the cantilevered deck slab of the double-lane concrete box girder bridge, the two side surfaces of the support plate are inclined surfaces adapted to the outer surface of the web of the double-lane concrete box girder bridge, the two side surfaces of the support plate are respectively connected with the two side surfaces of the top surface through arc surfaces, the arc surfaces are adapted to the connecting surfaces between the bottom surface of the root of the cantilevered deck slab of the single-lane concrete box girder bridge and the outer surface of the web, the top plate is attached to the bottom surface of the cantilevered deck slab of the double-lane concrete bridge and the outer surface of the web of the double-lane concrete bridge, the middle part of the top plate is provided with a plurality of rows of pre-embedded steel bar mounting holes, the number of pre-embedded steel bar mounting holes in each row is two and each row of pre-embedded steel bar mounting holes is located on the front side and the rear side of the support plate one by one, and one pre-embedded steel bar is fixedly installed in each pre-embedded steel bar mounting hole, and the two sides of the top plate are respectively provided with a plurality of rows of chemical anchor mounting holes, the number of chemical anchor mounting holes in each row is two and each row of chemical anchor mounting holes is located on the front side and the rear side of the support plate one by one; Step three, first measure the chemical anchor mounting positions on the cantilevered deck slab and the web of the double-lane concrete box girder bridge corresponding to the chemical anchor mounting holes on the splicing steel support, mark and punch the chemical anchor mounting positions on the cantilevered deck slab and the web of the double-lane concrete box girder bridge, and then implant one chemical anchor in each chemical anchor mounting position on the cantilevered deck slab and the web of the double-lane concrete box girder bridge; Step four, after the chemical anchors on the cantilevered deck slab and the web of the double-lane concrete box girder bridge are solidified and reach a certain strength, hoist the splicing steel support, so that the splicing steel support is located below the cantilevered deck slab of the double-lane concrete box girder bridge, the chemical anchors on the double-lane concrete box girder bridge are inserted into the chemical anchor mounting holes on the splicing steel support one by one, a fastening nut is installed on each chemical anchor, the splicing steel support is hung by the chemical anchors, the top plate of the splicing steel support is attached to the bottom surface of the cantilevered deck slab of the double-lane concrete bridge and the outer surface of the web of the double-lane concrete bridge by applying a pre-tightening force to the fastening nut, and the plurality of rows of pre-embedded steel bars on the splicing steel support are inserted between the exposed deck slab steel bars of the double-lane concrete box girder bridge; Step five, install pouring formwork in the middle of the top panel of the splicing steel support between the cantilevered outer ends of the deck slab of the double-lane concrete box girder bridge, and then bind the steel mesh on the exposed deck slab steel reinforcement of the double-lane concrete box girder bridge and the embedded steel reinforcement on the splicing steel support in the pouring formwork; Step six, pour concrete into the pouring formwork to form a splicing belt, and after the cast-in-place splicing belt cools for 28 days, remove the pouring formwork and complete the construction.

2. The method of splicing an existing dual-span concrete box girder bridge according to claim 1, wherein, When step two is performed, multiple reinforcing rib plates are arranged between the top two side faces of the support plate and the bottom face of the top panel, and multiple reinforcing rib plates are also arranged between the bottom two side faces of the support plate and the top face of the bottom panel.

3. The method of splicing an existing dual-span concrete box girder bridge according to claim 1 or 2, characterized in that, When step two is performed, multiple lightening holes are formed on the support plate.

4. The method of splicing an existing dual-span concrete box girder bridge according to claim 1, wherein, When step five is performed, the steel mesh is formed by binding multiple transverse steel reinforcements and multiple longitudinal steel reinforcements.

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