Construction method for removing old bridge and newly building bridge without interrupting traffic

Abstract

The invention discloses a construction method for removing an old bridge and newly building bridges without interrupting traffic. The construction method comprises the following steps that a first bridge and a second bridge are newly built on the two sides of an original old bridge correspondingly; two-way traffic on the old bridge is guided to the first bridge firstly, and then the old bridge is dismantled; bridge decks flush with the surface of the second bridge are installed on the two sides of the second bridge, so that bidirectional widening of the second bridge is completed; two-way traffic on the first bridge is guided to the widened second bridge, and the first bridge is closed; bridge decks flush with the surface of the first bridge are installed on the two sides of the first bridge, so that bidirectional widening of the first bridge is completed; and then the traffic flow in one direction is guided to the widened first bridge, and only the one-way traffic flow in the other direction is reserved on the second bridge. According to the method, the transformation mode of double-side bridge building and two-way widening is adopted, the defects of existing single-side widening and double-side widening are overcome, the defects existing after double-width bridges are widened are overcome, and the later maintenance cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of widening existing bridges, and in particular relates to a method for dismantling an old bridge and building a new bridge without interrupting traffic. Background Art

[0002] With the development of society, the navigation level of rivers will change. Due to the improvement of the navigation level of rivers, a large number of existing bridges do not meet the new navigation standards of rivers and need to be demolished and rebuilt. At the same time, due to the age of existing bridges, the number of lanes is generally small, which makes it difficult to meet the needs of modern transportation and needs to be widened and renovated. Therefore, in the upgrading and renovation of old bridges, it is of great significance to ensure that bridge traffic is not interrupted and realize the phased implementation plan of "build-demolition-build" bridges.

[0003] In the construction of road widening, upgrading and reconstruction, ensuring uninterrupted traffic is a very important research topic. Bridges, especially large bridges, are often the control nodes of road traffic lines. The smoothness of the bridge controls the smoothness of the road line on which it is located. As a large-scale transportation facility, the construction period of the bridge structure is often relatively long. In the road widening and upgrading project, if the bridge cannot guarantee the existing traffic during the construction process, during the construction period of several years, the direct or indirect economic losses caused by the closure of the bridge due to the interruption of personnel and logistics or longer detours are often relatively huge.

[0004] During the process of demolition, reconstruction, widening and reconstruction of existing bridges, it is generally required to maintain the normal operation of the traffic on the road section. The current common practices are: 1. Use a new temporary bridge for relief; 2. Single-side widening and reconstruction; 3. Double-side widening and reconstruction. The construction method of single-side widening and reconstruction is: 1) Build a new bridge on one side of the existing bridge that meets the new navigation standards and new traffic volume requirements; 2) After the new bridge is built, the old bridge is demolished to complete the construction. The construction method of double-side widening and reconstruction is: 1) Build two new bridges on both sides of the existing bridge that meet the new navigation standards and temporary traffic relief needs; 2) After the new bridge is built, the old bridge is demolished; 3) Rebuild the bridge at the site of the old bridge, and together with the first step of building a new bridge, it forms a bridge that meets the new traffic volume requirements.

[0005] These three widening and transformation methods have certain advantages and disadvantages:

[0006] 1. Plan for building a temporary bridge. Temporary bridges are generally only used during the construction of permanent bridges. After the bridge is built, they often cannot be used anymore and are directly demolished, which will cause a great waste of funds.

[0007] 2. Single-sided widening and reconstruction has no intersection between the old and new bridges, and the construction is simple and convenient. However, the overall line shape of the road after completion will deviate greatly from the overall line shape of the road of the existing bridge, which will lead to major changes in the road engineering of the bridge connection section. In cities, it generally involves a large amount of demolition and there is a certain degree of implementation difficulty, especially for routes within the city. The resulting increase in construction cost will be huge.

[0008] 3. The overall line shape of the road after the double-sided widening reconstruction is consistent with the overall line shape of the road of the existing bridge, and the amount of demolition is less than that of the single-sided widening. However, it is implemented in two steps. After completion, there are multiple bridges in the horizontal direction between the newly built bridge in the first stage and the rebuilt bridge in the second stage, and there is isolation in the same direction, which cannot meet the needs of vehicle interweaving conversion. If the newly built bridge and the rebuilt bridge are spliced ​​horizontally, the needs of vehicle interweaving conversion can be met, but the horizontal widening is due to the age difference between the newly built bridge and the rebuilt bridge at the location of the old bridge. Even if the segmental prefabricated cantilever assembly is used, it can only reduce the deformation caused by concrete shrinkage, but cannot reduce the impact of concrete creep. Therefore, the deformation of the new and old beam bridges is not synchronized; after the post-cast strip is used to widen and connect into a whole, there must be tensile stress in the post-cast strip. This tensile stress will have an adverse effect on the post-cast strip. If it exceeds the material strength of the post-cast strip, it will tear the post-cast strip and produce visible cracks; secondly, for the spliced ​​bridge, the foundation settlement of the box girder of the new bridge has been basically completed, while the foundation settlement of the rebuilt bridge has not yet occurred completely because it has not been opened to traffic. If the foundation soil of the new box girder is not properly handled, resulting in excessive settlement, it will have an adverse effect on the superstructure of the widened bridge, causing greater additional forces to be generated in the bridge beam, thus affecting the safe use of the structure. Summary of the invention

[0009] The purpose of the present invention is to overcome the existing technical defects and provide a method for demolishing an old bridge and building a new bridge without interrupting traffic. The reconstruction method of newly building a bridge on both sides + widening in both directions is adopted to avoid the disadvantages of existing single-sided widening and double-sided widening, and avoid the disadvantages of double-span bridges after widening, thereby reducing the cost of later repair and maintenance.

[0010] In order to solve the above technical problems, the present invention provides another method for demolishing an old bridge and building a new bridge without interrupting traffic, comprising the following steps:

[0011] S1. A first bridge and a second bridge are newly built on both sides of the original old bridge, and a plurality of first connecting members spaced apart along the extending direction of the bridges are buried at the flanges at the upper ends of both sides of the first bridge and the second bridge, and a plurality of second connecting members spaced apart along the extending direction of the bridges are buried at the lower ends of both sides of the webs of the first bridge and the second bridge;

[0012] S2, directing the two-way traffic on the old bridge to the first bridge, closing the old bridge and the second bridge, and then demolishing the old bridge;

[0013] S3, installing bridge panels flush with the surface of the second bridge on the upper ends of both sides, the inner end of the bridge panel is fixed to the first connecting member, and the bottom of the outer end of the bridge panel is fixed to the second connecting member through an inclined cantilever strut to complete the bidirectional widening of the second bridge;

[0014] S4, directing the two-way traffic on the first bridge to the widened second bridge and closing the first bridge;

[0015] S5. Bridge panels flush with the surface of the first bridge are installed on the upper ends of both sides of the first bridge, the inner ends of the bridge panels are fixed to the first connecting member, and the bottom of the outer ends of the bridge panels are fixed to the second connecting member through inclined cantilever struts to complete the two-way widening of the first bridge; then the traffic in one direction is guided to the widened first bridge, and only the one-way traffic in the other direction is retained on the second bridge, so that the widened first bridge forms a new one-way left-span bridge and the widened second bridge forms a new one-way right-span bridge.

[0016] Furthermore, in steps S3 and S5, the inner end of the bridge deck is fixed to the first connecting member by welding or bolting, the outer end of the bridge deck is fixed to one end of the cantilever strut by welding or bolting, and the other end of the cantilever strut is fixed to the second connecting member by welding or bolting.

[0017] Furthermore, in steps S3 and S5, slow lanes and sidewalks are provided on the outermost sides of the widened first bridge and the second bridge.

[0018] Furthermore, after step S5, the following steps are also included:

[0019] S6. Build a rain shelter over the whole or part of the sidewalk.

[0020] Furthermore, in step S6, stepped leisure seats are set up on the sidewalks below the awnings of the first bridge and the second bridge.

[0021] Furthermore, after step S6, the following steps are also included:

[0022] S7. A first viewing platform is set up at a position on the outer side of the bridge deck corresponding to the leisure sitting steps, and a third connecting member is provided at a position on the outer side of the bridge deck corresponding to the first viewing platform. The first viewing platform and the third connecting member are fixed by welding or bolting.

[0023] Furthermore, after step S7, the following steps are also included:

[0024] S8. A second viewing platform is set up below the first viewing platform, wherein the inner end of the second viewing platform is connected to the lower end of the web of the bridge, and the outer end surface of the second viewing platform is connected to the bottom of the bridge deck via an inclined pull rod; and a staircase connecting the first viewing platform and the second viewing platform is set up between the two.

[0025] Furthermore, a plurality of fourth connecting members are embedded in the lower ends of the webs on the outer sides of the first bridge and the second bridge at positions corresponding to the second viewing platform, and a fifth connecting member is provided at the bottom of the bridge deck at a position corresponding to the second viewing platform; the inner end of the second viewing platform is fixed to the fourth connecting member by welding or bolting, the outer end surface is fixed to one end of the pull rod by welding or bolting, and the other end of the pull rod is fixed to the fifth connecting member by welding or bolting.

[0026] Furthermore, after step S8, the following steps are also included:

[0027] S9. A transverse passage is set up at the bottom of the box girders of the first bridge and the second bridge, and is located below the second viewing platforms on both sides. Both ends of the transverse passage are connected to the second viewing platforms above through stairs, so that the viewing platforms on the first bridge and the second bridge are connected.

[0028] Furthermore, a plurality of sixth connecting members are embedded in the bottom of the box girders of the first bridge and the second bridge, and the transverse passage is fixed to the sixth connecting members by welding or bolting.

[0029] The present invention has the following beneficial effects:

[0030] 1. The bridge construction method of building new bridges on both sides + widening in both directions can make full use of the reserved space on the site after the demolition of the old bridge. The center line of the road does not change compared with the original road, and the road line shape is straight and smooth. It can also minimize the scope of land acquisition and demolition. During the process of building new bridges and demolishing old bridges, there is no need to interrupt traffic, and there is no need to build temporary traffic relief bridges. After completion, the appearance of the bridge deck is only two bridges, and the bridge deck landscape effect is good. The two new bridges (the first bridge and the second bridge) are directly widened by fixing the bridge deck. There is no connection between the old bridge and the new bridge, which reduces the deflection difference caused by the different stiffness of the new and old bridges, and can reduce the impact of concrete shrinkage creep at the joint when the new and old bridges are spliced ​​and the impact of uneven foundation settlement.

[0031] 2. The widening method on both sides of the new bridge adopts prefabricated assembly structure. The cantilever struts of the widened structure adopt steel structure, and the bridge deck of the widened structure adopts prefabricated concrete slabs or steel plate beams. It is assembled with the two bridges through welding, bolting and other connection methods. It not only achieves the speed of construction, but also reduces the impact of construction on the environment, meeting the green construction requirements.

[0032] 3. This plan fully considers the "people-oriented" design principle in the bridge upgrading and reconstruction. A slow-moving system (i.e., slow lanes and sidewalks) is set up in the final structural system after the entire bridge reconstruction is completed. The slow-moving system is meticulously equipped with pedestrian canopies, protruding viewing platforms, and a suspended horizontal crossing system (i.e., horizontal crossing passages) under the bridge for convenient crossing, which fully highlights the humanized design.

[0033] 4. This plan can be implemented in phases according to the near- and long-term planning and construction funding conditions, and the original old bridge can be optimized and utilized, which can effectively alleviate the current tight construction funding situation. When meeting the current traffic demand, the main structure of the new bridges on both sides can be implemented in the first phase, the old bridges can be retained, and heavy traffic such as vehicle loads can be transferred to the new bridge structure, while the retained old bridges can be used as light traffic channels such as non-motorized vehicle lanes and sidewalks; in the later stage, as the traffic demand increases and the construction funds are in place, the second-phase structure can be built on the basis of the first-phase implementation using the pre-buried connectors on the new bridge, the old bridge can be dismantled, and the second-phase widening can be implemented on the main structure of the first-phase new bridge. This plan fully reflects the refined design, combined with the near- and long-term traffic demand planning and the near- and long-term construction funds, and implemented in phases. It can not only solve the problem of renovating the old bridges with serious diseases under the condition of limited construction funds in the near term to meet the near-term traffic demand, but also reserve the conditions for the implementation of the second phase, and implement the second phase structure after the later construction funds are in place and the traffic demand increases.

[0034] Additional aspects and advantages of the present invention will be given in part in the following description, which will become obvious from the following description, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute an improper limitation of the present invention. In the drawings:

[0036] Figure 1 This is a schematic diagram of a first bridge and a second bridge newly built on both sides of an old bridge in an embodiment;

[0037] Figure 2 This is a schematic diagram of a new bridge after the pile foundation cap is constructed in the embodiment;

[0038] Figure 3 This is a schematic diagram of a new bridge after the construction of the bridge piers in the embodiment;

[0039] Figure 4 This is a schematic diagram of a new bridge after the main beam is constructed in the embodiment;

[0040] Figure 5 This is a schematic diagram of the construction of a new bridge after the main beam is closed in the embodiment;

[0041] Figure 6This is a schematic diagram of the construction of a new bridge after the support is erected and the arch rib is constructed in the embodiment;

[0042] Figure 7 This is a schematic diagram of the construction of a new bridge after the construction of the suspender in the embodiment;

[0043] Figure 8 This is a schematic diagram of the demolition of the old bridge in Example 2;

[0044] Fig. 9 This is a schematic diagram of the widening of both sides of the second bridge in Example 2;

[0045] Fig.10 This is a schematic diagram of the first bridge after widening on both sides in Example 2;

[0046] Fig.11 It is a schematic diagram of the rain shelters set up on the two bridges in Example 2;

[0047] Fig.12 It is a schematic diagram of the second bridge in Example 2 having the third connecting member to the sixth connecting member;

[0048] Fig.13 It is a schematic diagram of the first bridge in Example 2 having the third connecting member to the sixth connecting member;

[0049] Fig.14 This is a schematic diagram of Example 2 after a viewing platform, steps, stairs and a horizontal passage are provided on the bridge. DETAILED DESCRIPTION

[0050] In order to more fully understand the technical content of the present invention, the present invention will be further introduced and explained in conjunction with the accompanying drawings and specific embodiments below; it should be noted that if there are descriptions such as "first", "second", etc. in the text, they are used to distinguish different components, etc., and do not represent the order of precedence, nor do they limit the "first" and "second" to be different types.

[0051] In the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0052] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0053] Example 1

[0054] The method for demolishing an old bridge and building a new bridge without interrupting traffic shown in this embodiment includes the following steps:

[0055] a. Figure 1 As shown, a first bridge 1 and a second bridge 2 are newly built on both sides of the original old bridge 10. In order to achieve uninterrupted traffic when the new bridge is built, the new bridge in this implementation scheme adopts a split-section design, and the left and right sections of the new bridge are separately arranged on the left and right sides of the existing old bridge. During the implementation of the new bridge, the old bridge is retained to maintain the current traffic. After the two bridges are completed, they are open to traffic to meet the traffic relief requirements during the demolition of the old bridge. In a specific implementation case, the first bridge and the second bridge are preferably double-lane.

[0056] In the above, a plurality of first connectors 11 are embedded in the flanges at the upper ends of both sides of the first bridge 1 and the second bridge 2 and are spaced apart along the extension direction of the bridges, and a plurality of second connectors 12 are embedded in the lower ends of the webs at both sides of the first bridge and the second bridge and are spaced apart along the extension direction of the bridges.

[0057] In one embodiment, with refined planning, rational use of old facilities, and the gradual increase of projects implemented in phases in near- and long-term plans, it is of practical significance to study and propose a bridge plan for rational use of old bridges and phased implementation of new bridges for bridge facilities. This plan can be implemented in phases according to the near- and long-term planning and construction funding conditions, and can optimize the use of the original old bridges, which can effectively alleviate the current tight construction funding situation. When meeting the current traffic demand, the main structure of the two new bridges on both sides can be implemented in the first phase, the old bridge can be retained, and heavy traffic such as vehicle loads can be transferred to the two new bridges, while the retained old bridge can be used as a light traffic channel such as a non-motorized vehicle lane and a sidewalk; in the later stage, as the traffic demand increases and the construction funds are in place, the second phase structure can be built on the basis of the first phase implementation using the pre-buried connectors on the new bridge, the old bridge can be demolished, and the second phase of the two-way widening of the bridge can be implemented on the main structure of the first phase new bridge. This plan fully reflects the refined design, combined with the short- and long-term traffic demand planning and the short- and long-term construction funding situation, and can be implemented in phases. It can not only solve the problem of the renovation of old bridges with serious defects under the condition of limited construction funds in the short term to meet the short-term traffic demand, but also reserve the conditions for the implementation of the second phase, and implement the second phase structure after the later construction funds are in place and the traffic demand increases.

[0058] In one embodiment, both the first bridge and the second bridge adopt box sections, and concrete box girders or steel box girders can be used according to actual engineering conditions.

[0059] In the embodiment, as shown in the figure, in order to improve the spanning capacity of the newly built first bridge and the second bridge and reduce the beam height, an arch-beam combined force bearing system can be adopted, and arch ribs are newly built above the beam body and hangers are used to assist the beam body in bearing force; the specific construction process of the first bridge and the second bridge is as follows:

[0060] The first step, such as Figure 2 As shown, a bridge pile foundation cap 100 is constructed, and the pile foundation cap includes four pile foundation caps distributed front and back;

[0061] The second step is, Figure 3 As shown, during the construction of the bridge pier 101, the piers on the two middle pile foundation caps 100 are V-shaped support beam structures, and a hanging basket 102 is set up on the V-shaped support beam structure;

[0062] The third step is Figure 4 As shown, a main beam 103 is cantilevered and constructed symmetrically between the piers on both sides by using a hanging basket, and the main beam adopts a concrete box section;

[0063] The fourth step is Figure 5 As shown, the main beam 103 is closed to complete the overall structure of the main beam;

[0064] Step 5: Figure 6 As shown, a bracket 104 is set up on the main beam 103 to construct an arch rib 105, and the arch rib adopts a steel tube truss arch;

[0065] Step 6: Figure 7 As shown, the bracket 104 is removed, and a hanger 106 is constructed between the arch rib 105 and the main beam 103 to connect the arch rib and the main beam with the hanger; the hanger and the V-shaped pier support structure assist the main beam in bearing force, so that the span of the main beam can be made larger and the beam body can be made thinner.

[0066] Example 2

[0067] The method for demolishing an old bridge and building a new bridge without interrupting traffic shown in this embodiment, based on the construction method described in Example 1, also includes the following steps:

[0068] b. Direct the two-way traffic of the original old bridge to the first bridge 1, close the old bridge and the second bridge, and use the first bridge to relieve traffic.

[0069] c. Figure 8 As shown, the old bridge was demolished.

[0070] d. Fig. 9As shown, bridge panels 21 flush with the surface of the second bridge 2 are installed in sequence from front to back on the upper ends of both sides, the inner end of the bridge panel 21 is fixed to the first connecting piece 11 on the second bridge, and the bottom of the outer end of the bridge panel 21 is fixed to the second connecting piece 12 on the second bridge through an inclined cantilever strut 22, thereby forming a triangular support structure, improving the structural stability and reliability of the widening structure, and completing the two-way widening of the second bridge 2, so that the second bridge is widened from a two-lane design to a five-lane design. On the outermost side of the second bridge, a sidewalk 25 and a slow lane 26 (i.e., a non-motorized vehicle lane) are divided in sequence from the outside to the inside.

[0071] Preferably, the inner end of the bridge deck 21 is fixed to the first connecting member 11 by welding or bolting, the outer end of the bridge deck 21 is fixed to one end of the cantilever strut 22 by welding or bolting, and the other end of the cantilever strut 22 is fixed to the second connecting member 12 by welding or bolting.

[0072] Preferably, the cantilever struts 22 of the widened structure are made of steel structure, and the bridge deck 21 of the widened structure is made of precast concrete slabs or steel plate beams.

[0073] As a preference, Fig.12 As shown, a third connector 23 is provided at the outer end of the bridge deck 21, and a fifth connector 24 is provided at the bottom; when the bridge deck 21 adopts a steel plate beam, the third connector 23 and the fifth connector 24 are welded or bolted to the bridge deck, and when the bridge deck 21 adopts a concrete slab, the third connector 23 and the fifth connector 24 are pre-embedded in the bridge deck.

[0074] Preferably, the bridge deck 21 and the cantilever struts 22 are produced in sections by factory prefabrication, and then assembled on site and connected and fixed to the bridge. This not only ensures the construction quality of the components, but also shortens the on-site construction period and reduces pollution to the environment. It is increasingly used in bridge construction.

[0075] e. Direct the two-way traffic on the first bridge to the widened second bridge and close the first bridge.

[0076] f. Fig.10As shown, bridge panels 21 flush with the surface of the first bridge 1 are installed in sequence from front to back on the upper ends of both sides of the first bridge 1, the inner end of the bridge panel 21 is fixed to the first connecting member 11 on the first bridge, and the bottom of the outer end of the bridge panel 21 is fixed to the second connecting member 12 on the first bridge through an inclined cantilever strut 22, thereby forming a triangular support structure, improving the structural stability and reliability of the widening structure, and completing the two-way widening of the first bridge 1, so that the first bridge is widened from a two-lane design to a five-lane design, and the outermost side of the first bridge is divided into a sidewalk 25 and a slow lane 26 (i.e., a non-motorized vehicle lane) from the outside to the inside.

[0077] Preferably, the inner end of the bridge deck 21 is fixed to the first connecting member 11 by welding or bolting, the outer end of the bridge deck 21 is fixed to one end of the cantilever strut 22 by welding or bolting, and the other end of the cantilever strut 22 is fixed to the second connecting member 12 by welding or bolting.

[0078] Preferably, the cantilever struts 22 of the widened structure are made of steel structure, and the bridge deck 21 of the widened structure is made of precast concrete slabs or steel plate beams.

[0079] As a preference, Fig.13 As shown, a third connector 23 is provided at the outer end of the bridge deck 21, and a fifth connector 24 is provided at the bottom; when the bridge deck 21 adopts a steel plate beam, the third connector 23 and the fifth connector 24 are welded or bolted to the bridge deck, and when the bridge deck 21 adopts a concrete slab, the third connector 23 and the fifth connector 24 are pre-embedded in the bridge deck.

[0080] g. Then guide the traffic in one direction on the second bridge to the widened first bridge, and only retain the one-way traffic in the other direction on the second bridge, so that the widened first bridge forms a new one-way left bridge and the widened second bridge forms a new one-way right bridge.

[0081] h. Fig.11 and Fig.14 As shown, a canopy 3 is set up above the entire sidewalk 25 or the local position corresponding to the V-shaped pier in the sidewalk 25, and stepped leisure seats 4 are set up on the sidewalk below the canopy 3 of the first bridge 1 and the second bridge 2 for people to rest and sightsee.

[0082] i. Such as Figures 11 to 14 As shown, a first viewing platform 5 is set up at a position corresponding to the leisure seat step 4 at the outer end of the bridge deck 21, and the first viewing platform 5 is fixed to the third connecting member 23 by welding or bolting.

[0083] In one embodiment, the first viewing platform 5 is made of prefabricated concrete panels or steel panels.

[0084] j. Figures 11 to 14 As shown, a second viewing platform 6 is set up below the first viewing platform 5, and a plurality of fourth connecting members 13 are buried at the lower ends of the outer webs of the first bridge 1 and the second bridge 2, the inner end of the second viewing platform 6 is fixed to the fourth connecting member 13 at the lower end of the bridge web by welding or bolting, and the outer end surface of the second viewing platform 6 is connected to the bottom of the bridge deck 21 by an inclined tie rod 61, wherein the outer end surface of the second viewing platform 6 is fixed to one end of the tie rod 61 by welding or bolting, and the other end of the tie rod 61 is fixed to the fifth connecting member 24 at the bottom of the bridge deck 21 by welding or bolting; and a staircase 7 is set up between the first viewing platform 5 and the second viewing platform 6 to connect the two, so that people can flow between the upper and lower viewing platforms.

[0085] Preferably, the first viewing platform 6 is made of prefabricated concrete slabs or steel slabs.

[0086] k. Figures 11 to 14 As shown, a transverse passage 8 is set up at the bottom of the box girders of the first bridge and the second bridge and is located below the second viewing platforms on both sides, that is, the transverse passage 8 is set along the width direction of the two bridges, and the two ends of the transverse passage 8 are connected to the second viewing platform 6 above through stairs 7, so that the viewing platforms on the first bridge 1 and the second bridge 2 are connected, forming a transverse crossing system suspended under the two bridges, so as to achieve the purpose of pedestrians crossing the road.

[0087] As a preference, Figure 12 to Figure 14 As shown, the transverse passage 8 is preferably assembled by welding of steel structures, and a plurality of sixth connecting members 14 spaced apart along the width direction are buried at the bottom of the first bridge 1 and the second bridge 2. The transverse passage 8 is fixed to the sixth connecting members 14 at the bottom of the bridge by welding or bolting.

[0088] Preferably, in order to improve the stability and fixing force of the transverse passage 8, a connecting rod (not shown in the figure) connecting the second viewing platform 6 and the transverse passage 8 is provided between the two.

[0089] Preferably, the transverse passage 8 is located in the V-shaped groove of the V-shaped bridge pier.

[0090] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for demolishing an old bridge and building a new bridge without interrupting traffic, characterized in that: The following steps are involved: S1. A first bridge and a second bridge are newly built on both sides of the original old bridge, and a plurality of first connecting members spaced apart along the extending direction of the bridges are buried at the flanges at the upper ends of both sides of the first bridge and the second bridge, and a plurality of second connecting members spaced apart along the extending direction of the bridges are buried at the lower ends of both sides of the webs of the first bridge and the second bridge; S2, directing the two-way traffic on the old bridge to the first bridge, closing the old bridge and the second bridge, and then demolishing the old bridge; S3, installing bridge panels flush with the surface of the second bridge on the upper ends of both sides, the inner end of the bridge panel is fixed to the first connecting member, and the bottom of the outer end of the bridge panel is fixed to the second connecting member through an inclined cantilever strut to complete the bidirectional widening of the second bridge; S4, directing the two-way traffic on the first bridge to the widened second bridge and closing the first bridge; S5. Bridge panels flush with the surface of the first bridge are installed on the upper ends of both sides of the first bridge, the inner ends of the bridge panels are fixed to the first connecting member, and the bottom of the outer ends of the bridge panels are fixed to the second connecting member through inclined cantilever struts to complete the two-way widening of the first bridge; then the traffic in one direction is guided to the widened first bridge, and only the one-way traffic in the other direction is retained on the second bridge, so that the widened first bridge forms a new one-way left-span bridge and the widened second bridge forms a new one-way right-span bridge.

2. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 1, characterized in that: In steps S3 and S5, the inner end of the bridge deck is fixed to the first connecting member by welding or bolting, the outer end of the bridge deck is fixed to one end of the cantilever strut by welding or bolting, and the other end of the cantilever strut is fixed to the second connecting member by welding or bolting.

3. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 1 or 2, characterized in that: In steps S3 and S5, slow lanes and sidewalks are provided on the outermost sides of the widened first bridge and the second bridge.

4. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 3, characterized in that: After step S5, the following steps are also included: S6. Build a rain shelter over the whole or part of the sidewalk.

5. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 4, characterized in that: In step S6, stepped leisure seats are set up on the sidewalks below the awnings of the first bridge and the second bridge.

6. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 5, characterized in that: After step S6, the following steps are also included: S7. A first viewing platform is set up at a position on the outer side of the bridge deck corresponding to the leisure sitting steps, and a third connecting member is provided at a position on the outer side of the bridge deck corresponding to the first viewing platform. The first viewing platform and the third connecting member are fixed by welding or bolting.

7. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 6, characterized in that: After step S7, the following steps are also included: S8. A second viewing platform is set up below the first viewing platform, wherein the inner end of the second viewing platform is connected to the lower end of the web of the bridge, and the outer end surface of the second viewing platform is connected to the bottom of the bridge deck via an inclined pull rod; and a staircase connecting the first viewing platform and the second viewing platform is set up between the two.

8. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 7, characterized in that: A plurality of fourth connecting members are embedded in the lower end of the webs on the outer sides of the first bridge and the second bridge at positions corresponding to the second viewing platform, and a fifth connecting member is provided at the bottom of the bridge deck at a position corresponding to the second viewing platform; the inner end of the second viewing platform is fixed to the fourth connecting member by welding or bolting, the outer end surface is fixed to one end of the pull rod by welding or bolting, and the other end of the pull rod is fixed to the fifth connecting member by welding or bolting.

9. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 8, characterized in that: After step S8, the following steps are also included: S9. A transverse passage is set up at the bottom of the box girders of the first bridge and the second bridge, and is located below the second viewing platforms on both sides. Both ends of the transverse passage are connected to the second viewing platforms above through stairs, so that the viewing platforms on the first bridge and the second bridge are connected.

10. The method for demolishing an old bridge and building a new bridge without interrupting traffic as claimed in claim 9, characterized in that: A plurality of sixth connecting members are embedded in the bottom of the box girders of the first bridge and the second bridge, and the transverse passage is fixed to the sixth connecting members by welding or bolting.

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