Splicing method of existing double-width concrete box girder bridge

Abstract

The invention discloses a splicing method of an existing double-width concrete box girder bridge, which comprises the following steps of: firstly chiseling away concrete at the outer end of a bridge deck cantilever of a double-width bridge, and retaining a steel bar at the outer end of the bridge deck cantilever; a spliced steel support is manufactured, wherein the spliced steel support comprises a supporting plate, a top face plate and a bottom face plate; a plurality of rows of embedded steel bars are mounted in the middle of the top panel; a plurality of rows of chemical anchor bolt mounting holes are formed in each of the two sides of the top panel; a chemical anchor bolt is implanted into each of a bridge deck cantilever and a web of the double-amplitude bridge; hoisting the spliced steel support, inserting the chemical anchor bolts on the double-width concrete box girder bridge into the chemical anchor bolt mounting holes in the spliced steel support in a one-to-one correspondence manner, and mounting a fastening nut on each chemical anchor bolt, so that a top panel of the spliced steel support is attached to the outer side surface of a web plate on the bottom surface of a bridge panel cantilever of the double-width bridge; mounting a pouring template and binding a reinforcing mesh; and concrete is poured into the pouring formwork, and the splicing belt is formed. The construction method is convenient to construct and high in construction efficiency.

Description

Technical Field

[0001] The invention relates to a method for splicing an existing double-span concrete box girder bridge. Background Art

[0002] Due to the special terrain and environment, many highway bridge projects currently have greatly reduced traffic capacity due to low design standards, aging materials, and insufficient lane width. The economic cost of rebuilding bridges is high, and it may also cause problems such as traffic interruption. In order to meet the growing traffic volume, bridge projects can be renovated and expanded to improve their performance by widening the original bridge deck. A double-span bridge is composed of two bridges side by side. Each bridge usually only allows vehicles to travel in one direction, which is suitable for scenes with large multi-lane traffic. Restricted by the overall layout of the road, there is often a wide gap between the double-span bridges. At present, this bridge splicing method can make full use of the existing box girder structure. Under the action of vehicle loads, the bridge deck locally forms a composite beam force system with good force performance, convenient construction, and high construction efficiency, but it is rarely used in bridge widening structures. With the rapid development of my country's social economy, the traffic volume of the road network has increased year by year, which makes it difficult for a large number of road bridges built in the early days to meet the current traffic operation needs, so there are more and more renovation and expansion projects. 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 utilize the structure of the original bridge, so that the widened (widened) bridge meets the existing technical specifications and also meets the existing functional requirements. After investigation and analysis, it is found that widening (widening) the old bridge can greatly save the cost on the premise of meeting the existing technical requirements and functional requirements. Therefore, considering factors such as economy and practicality, it is necessary to widen (widen) the old bridge that does not meet the functional requirements, so that the old bridge can be fully utilized and its economic value can be fully realized.

[0003] Widening is a high-tech project in reconstruction. The key technical issues include: widening method (different bridge widening methods and widening scheme selection), bridge deck cracking (stress analysis of the joint between the new bridge and the old bridge), whether the bearing capacity of the upper and lower structures of the bridge is sufficient, etc. These technical issues are directly related to the safety and stability of the bridge. Therefore, the present invention is of great significance.

[0004] At present, the splicing technology of new and old bridges in my country is relatively common, and the splicing of existing double-span cast-in-place box girders is extremely rare. Because the cantilever plate of cast-in-place box girders (especially rigid frame bridges) is large, the center strip of double-span bridges is wide, and the span of the bridge deck after splicing is large. This makes the concrete cracking at the splicing zone, the stress mode of the existing cantilever changes greatly after splicing, the splicing reconstruction has a great impact on the existing bridge deck, the existence of road arches after splicing, and the reduction of the redundancy of the bridge bearing capacity after reconstruction. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a method for splicing an existing double-span concrete box girder bridge. The method uses a spliced ​​steel support as a splicing member of the existing double-span box girder bridge. Under the load of vehicles, the spliced ​​steel support and the bridge deck of the existing double-span box girder bridge partially form a composite beam force system with good force performance, convenient construction and high construction efficiency.

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

[0007] Step 1: first, the concrete at the outer end of the bridge deck cantilever of the double-span concrete box girder bridge is chiseled off to form a splicing belt between the outer ends of the bridge deck cantilever of the double-span concrete box girder bridge after the chiseling, and the steel bars at the outer ends of the bridge deck cantilever of the double-span concrete box girder bridge are retained to make the thickness of the outer ends of the bridge deck cantilever of the double-span concrete box girder bridge meet the bearing capacity requirements, and the outer end surface of the bridge deck cantilever of the double-span concrete box girder bridge after the chiseling is polished;

[0008] Step 2: According to the actual situation and design requirements of the bridge body, a spliced ​​steel support is manufactured. The spliced ​​steel support includes a support plate, a top panel fixed on the top surface and both side surfaces of the support plate, and a bottom panel fixed on the support plate; the middle part of the top surface of the support plate is a horizontal plane, and the length of the middle part of the top surface of the support plate is adapted to the width of the splicing belt, the two sides of the top surface of the support plate are inclined surfaces adapted to the bottom surface of the bridge deck cantilever of the double-span concrete box girder bridge, the two side surfaces of the support plate are inclined surfaces adapted to the outer side surfaces of the web of the double-span concrete box girder bridge, the two side surfaces of the support plate are connected to the two sides of the top surface by arc surfaces respectively, and the arc surfaces are connected to the single-span concrete The bottom surface of the root of the bridge deck cantilever of the box girder bridge is adapted to the connecting surface of the outer side surface of the web, so that the top panel is attached to the bottom surface of the bridge deck cantilever of the double-span concrete bridge and the outer side surface of the web of the double-span concrete bridge; a plurality of rows of pre-embedded steel bar installation holes are provided in the middle of the top panel, the number of each row of pre-embedded steel bar installation holes is two and they are located one by one on the front and rear sides of the support plate, and one pre-embedded steel bar is fixedly installed in each pre-embedded steel bar installation hole; a plurality of rows of chemical anchor bolt installation holes are provided on both sides of the top panel, the number of each row of chemical anchor bolt installation holes is two and they are located one by one on the front and rear sides of the support plate;

[0009] Step three, first measuring the chemical anchor installation positions on the bridge deck cantilever and web of the double-span concrete box girder bridge corresponding to the chemical anchor installation holes on the spliced ​​steel support, marking and drilling the chemical anchor installation positions on the bridge deck cantilever and web of the double-span concrete box girder bridge, and then implanting a chemical anchor at each chemical anchor installation position on the bridge deck cantilever and web of the double-span concrete box girder bridge;

[0010] Step 4: after the chemical anchor bolts on the bridge deck cantilever and the web of the double-span concrete box girder bridge solidify and reach a certain strength, the spliced ​​steel support is hoisted so that the spliced ​​steel support is located below between the bridge deck cantilever of the double-span concrete box girder bridge, and the chemical anchor bolts on the double-span concrete box girder bridge are inserted into the chemical anchor bolt installation holes on the spliced ​​steel support one by one, and then a fastening nut is installed on each chemical anchor bolt so that the spliced ​​steel support is suspended by the chemical anchor bolt, and a pre-tightening force is applied to the fastening nut so that the top panel of the spliced ​​steel support is attached to the bottom surface of the bridge deck cantilever of the double-span concrete bridge and the outer side surface of the web of the double-span concrete bridge, and several rows of embedded steel bars on the spliced ​​steel support are inserted between the exposed bridge deck steel bars of the double-span concrete box girder bridge;

[0011] Step 5: Install a casting template in the middle of the top panel of the spliced ​​steel support between the outer ends of the bridge deck cantilever of the double-span concrete box girder bridge, and then tie a steel mesh to the exposed bridge deck steel bars of the double-span concrete box girder bridge and the embedded steel bars on the spliced ​​steel support in the casting template;

[0012] Step six: Pour concrete into the casting formwork to form a splicing strip. After the cast-in-place splicing strip has cooled for 28 days, remove the casting formwork and the construction is completed.

[0013] In the above-mentioned splicing method of the existing double-span concrete box girder bridge, when performing step 2, a plurality of reinforcing ribs are provided at intervals between the top two side surfaces of the support plate and the bottom surface of the top panel, and a plurality of reinforcing ribs are also provided at intervals between the bottom two side surfaces of the support plate and the top surface of the bottom panel.

[0014] In the above-mentioned method for splicing an existing double-span concrete box girder bridge, when performing step 2, a plurality of lightening holes are opened on the support plate.

[0015] In the above-mentioned method for splicing an existing double-span concrete box girder bridge, when performing step five, the steel mesh is formed by binding a plurality of transverse steel bars and a plurality of longitudinal steel bars.

[0016] The characteristics of the splicing method of the existing double-width concrete box girder bridge of the present invention are:

[0017] 1. Use spliced ​​steel supports as the splicing parts of the existing double-span concrete box girder bridge, which does not need to be dismantled. By opening lightening holes in the spliced ​​steel supports, not only the stress performance of the spliced ​​parts is excellent, but also the dead weight of the spliced ​​parts is small, the construction is convenient, and the interference to the surrounding environment is small.

[0018] 2. Chemical anchor bolts are used to connect the spliced ​​steel supports to the existing double-span concrete box girder bridge, which can not only bring shear resistance to the structure of the splicing belt, but also make the splicing belt have a certain anti-uplift effect.

[0019] 3. Use pre-buried steel bars to connect the spliced ​​steel supports to the cast-in-place splicing strips, making the construction more convenient, avoiding the difficulty of installing the spliced ​​parts, and improving the construction efficiency.

[0020] 4. The reinforcing ribs are integrated into the structure of the spliced ​​steel support to further enhance the strength and rigidity of the spliced ​​steel support, while also improving the bearing capacity of the spliced ​​steel support. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a perspective view of an existing double-span concrete box girder bridge of the present invention before being spliced;

[0022] Figure 2 is a schematic structural diagram after performing step 1 of the splicing method of the present invention;

[0023] Figure 3 is a perspective view of a spliced ​​steel support produced when performing step 2 of the splicing method of the present invention;

[0024] Figure 4 is a perspective view of the step 4 of the splicing method of the present invention;

[0025] Figure 5 is a perspective view after performing step 4 of the splicing method of the present invention;

[0026] Figure 6 is a perspective view after performing step five of the splicing method of the present invention;

[0027] Figure 7 It is a perspective view after performing step six of the splicing method of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] Please refer to Figures 1 to 7 The method for splicing an existing double-width concrete box girder bridge of the present invention comprises the following steps:

[0030] Step 1: First, use professional tools to chisel away the concrete at 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, so that a splicing strip 10 is formed 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 after the chiseling, and retain the steel bars 2 at the outer end of the bridge deck cantilever of the left existing concrete box girder bridge 1 and the steel bars 2 at the outer end of the bridge deck cantilever of the right existing concrete box girder bridge 3 (see Figure 2), so that the thickness of the outer end of the bridge deck cantilever of the left existing concrete box girder bridge 1 and the thickness of the outer end of the bridge deck cantilever of the right existing concrete box girder bridge 3 both meet the requirements of bearing capacity, and grind the outer end surface of the bridge deck cantilever of the left existing concrete box girder bridge 1 and the outer end surface of the bridge deck cantilever of the right existing concrete box girder bridge 3 after chiseling to ensure that the chiseled surface is flat and smooth;

[0031] Step 2: According to the actual situation and design requirements of the bridge body, a spliced ​​steel support 4 is manufactured. The spliced ​​steel support 4 includes a support plate 40, a top panel 41 fixed on the top surface and both side surfaces of the support plate 40, and a bottom panel 42 fixed on the support plate 40; the middle part of the top surface of the support plate 40 is a horizontal plane, and the length of the middle part of the top surface of the support plate 40 is adapted to the width of the splicing belt 10, and both sides of the top surface of the support plate 40 are inclined surfaces adapted to the bottom surface of the bridge deck cantilever of the existing concrete box girder bridge span 1 and the bottom surface of the bridge deck cantilever of the existing concrete box girder bridge span 3, and the two side surfaces of the support plate 40 are inclined surfaces adapted to the outer side surfaces of the web plate of the left-span existing concrete box girder bridge 1 and the web plate of the right-span existing concrete box girder bridge 3, and the two side surfaces of the support plate 40 are connected to both sides of the top surface by arc surfaces respectively, and the arc surfaces are connected to the single-span concrete box The bottom surface of the root of the bridge deck cantilever of the beam bridge is adapted to the connecting surface of the outer side surface of the web, so that the top panel 41 fits on the bottom surface of the bridge deck cantilever of the left existing concrete box girder bridge 1 and the outer side surface of the web, as well as the bottom surface of the bridge deck cantilever of the right existing concrete box girder bridge 3 and the outer side surface of the web; a plurality of lightening holes 400 are provided on the support plate 40; a plurality of reinforcing ribs 43 are provided at intervals between the top two side surfaces of the support plate 40 and the bottom surface of the top panel 41, and a plurality of reinforcing ribs 43 are also provided at intervals between the bottom two side surfaces of the support plate 40 and the top surface of the bottom panel 42; a plurality of rows of embedded steel bar installation holes are provided in the middle of the top panel 41, and the number of each row of embedded steel bar installation holes is two and they are located one by one on the front and rear sides of the support plate 40, and one embedded steel bar 5 (see Figure 3 ); A plurality of rows of chemical anchor bolt mounting holes are respectively provided on both sides of the top panel 41, and the number of each row of chemical anchor bolt mounting holes is two and they are located one by one on the front and rear sides of the support plate 40;

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

[0033] Step 4: After the chemical anchor bolts on the bridge deck cantilever and web of the left existing concrete box girder bridge 1 and the bridge deck cantilever and web of the right existing concrete box girder bridge 3 have solidified and reached a certain strength, a plurality of spliced ​​steel supports 4 are hoisted in sequence, so that the plurality of spliced ​​steel supports 4 are spaced below between the bridge deck cantilever of the left existing concrete box girder bridge 1 and the bridge deck cantilever of the right existing concrete box girder bridge 3, and the chemical anchor bolts 6 on the left existing concrete box girder bridge 1 and the chemical anchor bolts 6 on the right existing concrete box girder bridge 3 are inserted into the chemical anchor bolt installation holes on the plurality of spliced ​​steel supports 4 one by one, and then a fastening nut 7 (see FIG. 1 ) is installed on each chemical anchor bolt 6. Figure 4 ), so that a plurality of spliced ​​steel supports 4 are suspended by chemical anchor bolts 6, and by applying pre-tightening force to the fastening nuts 7, the top panels 41 of the spliced ​​steel supports 4 are attached to the bottom surface of the bridge deck cantilever and the outer surface of the web of the left existing concrete box girder bridge 1 and the bottom surface of the bridge deck cantilever and the outer surface of the web of the right existing concrete box girder bridge 3, and the rows of embedded steel bars 5 on the spliced ​​steel supports 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 5: Install a casting template 8 in the middle of the top panel 41 of the spliced ​​steel support 4 between the outer ends of the bridge deck cantilever of the left existing concrete box girder bridge 1 and the outer ends of the bridge deck cantilever of the right existing concrete box girder bridge 3, and then tie a steel mesh 9 to 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 spliced ​​steel support 4 in the casting template 8; the steel mesh 9 is formed by tying a plurality of transverse steel bars and a plurality of longitudinal steel bars (see Figure 6 );

[0035] Step 6: Pour concrete into the casting template 8 to form a splicing strip 10 (see Figure 7 ); During the pouring process, the construction personnel must strictly follow the construction process to ensure that the splicing strip 10 has good integrity and stability. After the cast-in-place splicing strip 10 cools for 28 days, the pouring template 7 is removed and the construction is completed.

[0036] The splicing method of the existing double-span concrete box girder bridge of the present invention tightly connects the left-span existing concrete box girder bridge 1 and the right-span existing concrete box girder bridge 3 through multiple splicing steel supports 4; wherein the splicing steel supports are connected to the left-span existing concrete box girder bridge 1 and the right-span existing concrete box girder bridge 3 through chemical anchor bolts 6, and are connected to the cast-in-place splicing belt 10 through embedded steel bars 5, and the chemical anchor bolts 6 and the embedded steel bars 5 provide a certain shear resistance for the splicing belt 10 between the left-span existing concrete box girder bridge 1 and the right-span existing concrete box girder bridge 3; a pre-tightening force is applied by tightening nuts 7 to generate a certain pressure on the splicing steel supports 4; reinforcing ribs 43 are set on the splicing steel supports 4 to enhance the structural rigidity and strength of the splicing steel supports 4 and improve the bearing capacity of the steel splicing steel supports 4; and lightening holes are opened on the support plates 40 of the splicing steel supports 4 to reduce the dead weight of the splicing steel supports 4, making the construction more convenient.

[0037] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A method for splicing an existing double-span concrete box girder bridge, characterized in that: The splicing method comprises the following steps: Step 1: first, the concrete at the outer end of the bridge deck cantilever of the double-span concrete box girder bridge is chiseled off to form a splicing belt between the outer ends of the bridge deck cantilever of the double-span concrete box girder bridge after the chiseling, and the steel bars at the outer ends of the bridge deck cantilever of the double-span concrete box girder bridge are retained to make the thickness of the outer ends of the bridge deck cantilever of the double-span concrete box girder bridge meet the bearing capacity requirements, and the outer end surface of the bridge deck cantilever of the double-span concrete box girder bridge after the chiseling is polished; Step 2: According to the actual situation and design requirements of the bridge body, a spliced ​​steel support is manufactured. The spliced ​​steel support includes a support plate, a top panel fixed on the top surface and both side surfaces of the support plate, and a bottom panel fixed on the support plate; the middle part of the top surface of the support plate is a horizontal plane, and the length of the middle part of the top surface of the support plate is adapted to the width of the splicing belt, the two sides of the top surface of the support plate are inclined surfaces adapted to the bottom surface of the bridge deck cantilever of the double-span concrete box girder bridge, the two side surfaces of the support plate are inclined surfaces adapted to the outer side surfaces of the web of the double-span concrete box girder bridge, the two side surfaces of the support plate are connected to the two sides of the top surface by arc surfaces respectively, and the arc surfaces are connected to the single-span concrete The bottom surface of the root of the bridge deck cantilever of the box girder bridge is adapted to the connecting surface of the outer side surface of the web, so that the top panel is attached to the bottom surface of the bridge deck cantilever of the double-span concrete bridge and the outer side surface of the web of the double-span concrete bridge; a plurality of rows of pre-embedded steel bar installation holes are provided in the middle of the top panel, the number of each row of pre-embedded steel bar installation holes is two and they are located one by one on the front and rear sides of the support plate, and one pre-embedded steel bar is fixedly installed in each pre-embedded steel bar installation hole; a plurality of rows of chemical anchor bolt installation holes are provided on both sides of the top panel, the number of each row of chemical anchor bolt installation holes is two and they are located one by one on the front and rear sides of the support plate; Step three, first measuring the chemical anchor installation positions on the bridge deck cantilever and web of the double-span concrete box girder bridge corresponding to the chemical anchor installation holes on the spliced ​​steel support, marking and drilling the chemical anchor installation positions on the bridge deck cantilever and web of the double-span concrete box girder bridge, and then implanting a chemical anchor at each chemical anchor installation position on the bridge deck cantilever and web of the double-span concrete box girder bridge; Step 4: after the chemical anchor bolts on the bridge deck cantilever and the web of the double-span concrete box girder bridge solidify and reach a certain strength, the spliced ​​steel support is hoisted so that the spliced ​​steel support is located below between the bridge deck cantilever of the double-span concrete box girder bridge, and the chemical anchor bolts on the double-span concrete box girder bridge are inserted into the chemical anchor bolt installation holes on the spliced ​​steel support one by one, and then a fastening nut is installed on each chemical anchor bolt so that the spliced ​​steel support is suspended by the chemical anchor bolt, and a pre-tightening force is applied to the fastening nut so that the top panel of the spliced ​​steel support is attached to the bottom surface of the bridge deck cantilever of the double-span concrete bridge and the outer side surface of the web of the double-span concrete bridge, and several rows of embedded steel bars on the spliced ​​steel support are inserted between the exposed bridge deck steel bars of the double-span concrete box girder bridge; Step 5: Install a casting template in the middle of the top panel of the spliced ​​steel support between the outer ends of the bridge deck cantilever of the double-span concrete box girder bridge, and then tie a steel mesh to the exposed bridge deck steel bars of the double-span concrete box girder bridge and the embedded steel bars on the spliced ​​steel support in the casting template; Step six: Pour concrete into the casting formwork to form a splicing strip. After the cast-in-place splicing strip has cooled for 28 days, remove the casting formwork and the construction is completed.

2. The method for splicing an existing double-span concrete box girder bridge according to claim 1 is characterized in that: During step 2, a plurality of reinforcing ribs are provided between the top two side surfaces of the support plate and the bottom surface of the top panel, and a plurality of reinforcing ribs are provided between the bottom two side surfaces of the support plate and the top surface of the bottom panel.

3. The method for splicing an existing double-span concrete box girder bridge according to claim 1 or 2, characterized in that: When performing step 2, a plurality of lightening holes are opened on the support plate.

4. The method for splicing an existing double-span concrete box girder bridge according to claim 1, characterized in that: When performing step five, the steel mesh is formed by binding a plurality of transverse steel bars and a plurality of longitudinal steel bars.

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