Design and construction method of concrete bridge temperature span structure

Abstract

The invention relates to the technical field of bridge structure design, in particular to a design and construction method of a concrete bridge temperature span structure. A breaking joint is formed in the middle span section of a beam body, a midspan telescopic device is arranged at the position of the breaking joint, and meanwhile the beam body is fixedly connected with a main pier; therefore, the beam bodies on the two sides of the breaking joint can freely move in the bridge direction, and the temperature span is from the main pier to the beam end or from the main pier to the middle of the span. The invention has the advantages that: 1) the structural stress is optimized, and the temperature span of the concrete bridge is greatly shortened; 2) the temperature span is shortened, the beam rail stress is greatly improved, and the investment is saved; as the influence of a rail temperature regulator is avoided, the line shape of the large-span concrete bridge is not limited any more, and line selection of railways and rail transit is more facilitated; after the temperature span is shortened, a fixing support of a middle fulcrum is omitted, investment is saved, main beam stretching caused by the temperature can be eliminated through the telescopic device, bending moment of the pier caused by temperature rise and temperature reduction of the main beam is avoided, and pier beam consolidation is not affected by the height of the pier.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge structure design, and in particular to a design and construction method of a concrete bridge temperature span structure. Background Art

[0002] With the development of high-speed railways and rail transit, ballastless track bridges are being used more and more, and a large number of large-span ballastless track bridges have been produced. However, ballastless tracks have high requirements for temperature resistance.

[0003] like Figure 1 As shown in the figure, the temperature span of the existing concrete continuous beam is from the fixed support to the beam end, i.e., the length L. If this length exceeds the normal temperature span, it is likely to cause deformation disharmony between the beam and the ballastless track, necessitating the use of a rail temperature regulator. However, rail temperature regulators are not only expensive and increase project investment, but also have high requirements for alignment. The inability to set the rail temperature on long-span bridges can even affect the overall alignment. Summary of the Invention

[0004] The purpose of the present invention is to provide a design and construction method for a temperature span structure of a concrete bridge based on the above-mentioned deficiencies of the prior art. By setting a longitudinal fracture in the mid-span section of the beam, the beams on both sides of the fracture can move along the bridge direction, and the bending moment and shear force are transmitted through the mid-span expansion device set at the fracture position, thereby optimizing the structural stress, greatly shortening the temperature span of the concrete bridge, and ensuring the coordination of the deformation of the beam and the ballastless track.

[0005] The purpose of the present invention is achieved by the following technical solutions: A design and construction method for a temperature span structure of a concrete bridge comprises a main pier, a side pier and a beam, wherein the beam is supported on the main pier and the side pier, the beam comprises a mid-span section and a side span section, and a ballastless track is arranged above the beam. The method is characterized in that: by providing a fracture in the mid-span section of the beam and a mid-span expansion device at the position of the fracture, the beam is simultaneously consolidated with the main pier, so that the beams on both sides of the fracture can freely displace along the bridge direction and the temperature span is from the main pier to the beam end or from the main pier to the mid-span.

[0006] The mid-span telescopic device includes a first telescopic member and a second telescopic member, wherein the first telescopic member is buried in the beam body near the end face on one side of the fracture, and the second telescopic member is buried in the beam body near the end face on the other side of the fracture, and the first telescopic member and the second telescopic member are clamped together; an expansion joint is provided between the first telescopic member and the beam body on the opposite side, and an expansion joint is provided between the second telescopic member and the beam body on the opposite side.

[0007] The bending and shearing strengths of the first telescopic member and the second telescopic member are not less than the structural strength of the beam body.

[0008] In construction, the following steps are included: The main pier is fixed with the beam body, the beam body is cast in situ or cast in situ to the last section, and the closing section is reserved; The first expansion component and the second expansion component are embedded on the top plate, the bottom plate and the web of the beam body, and the first expansion component and the second expansion component at the corresponding positions are clamped; Pouring concrete around each of the first expansion component and the second expansion component, and staggering the reserved expansion joint, completing the closing.

[0009] The midspan expansion device located on the top plate, the midspan expansion device located on the bottom plate and the midspan expansion device located on the web are arranged on different elevations on both sides of the midspan section centerline.

[0010] The first expansion component and the second expansion component are embedded in the respective corresponding beam body through the embedded part.

[0011] The beam body of the side span section and the side pier below it adopt a movable support in the bridge direction.

[0012] The advantages of the present application are: 1) The structure stress is optimized, and the concrete bridge temperature span is greatly shortened.

[0013] 2) The shortened temperature span greatly improves the beam rail stress, avoids the use of rail temperature regulator, ensures the deformation coordination of the beam body and the ballastless track, thereby saving investment; due to the influence of not setting the rail temperature regulator, the linear of the long-span concrete bridge is no longer limited, which is more favorable for the route selection of railway and rail transit.

[0014] 3) After the temperature span is shortened, the fixed support of the middle support point is saved, and the investment is saved.

[0015] 4) Because there is an expansion device in the midspan in the bridge direction, the expansion of the main beam caused by temperature can be eliminated through the expansion device, so that the bending moment of the pier caused by the temperature rise and fall of the main beam will not be generated, and the pier beam consolidation is not affected by the height of the pier.

[0016] 5) The structure is simple and reasonable, can be embedded in the beam body during prefabrication construction, construction is convenient, and is suitable for promotion. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a temperature span range diagram of a long-span concrete structure continuous beam in the prior art; Figure 2 It is a structural diagram of the present application (including temperature span range); Figure 3 It is a midspan elevation view of the present application; Figure 4 It is a top plate midspan plan view of the present application; Figure 5 is a top plate span neutral plane view of the present application; Figure 6 is a bottom plate span neutral plane view of the present application; Figure 7 is a bending moment diagram of a large-span concrete structure continuous beam in the prior art; Figure 8 is a bending moment diagram of the present application; Figure 9 is a temperature span range and main beam expansion direction schematic view of a large-span concrete structure continuous beam in the prior art; Figure 10 is a temperature span range and main beam expansion direction schematic view of the present application. DETAILED DESCRIPTION

[0018] The features of the present application and other related features are further described in detail below with reference to the accompanying drawings, in which: As shown in Figures 1-10 , the reference numerals 1-21 in the figure represent: main pier 1, beam body 2, pier beam consolidation point 3, bridge direction movable support 4, temperature span 5, span center expansion device 6, bottom plate 7, top plate 8, ballastless track 9, left top plate 10, right top plate 11, right side expansion component 12, upper side expansion joint 13, left side expansion component 14, lower side expansion joint 15, left bottom plate 16, right bottom plate 17, left side expansion component 18, right side expansion component 19, lower side expansion joint 20, upper side expansion joint 21.

[0019] Embodiment: As shown in Figures 1 to 10 , the design and construction method of the concrete bridge temperature span structure in the present embodiment includes main pier 1 and beam body 2, wherein the beam body 2 is supported on the main pier 1 and the side pier. The beam body between the two side main piers 1 is the mid-span section, and the section between the main pier and the side pier is the side span section. The ballastless track 9 is arranged above the beam body 2.

[0020] As shown in Figure 2 , the main pier 1 and the beam body 2 in the present embodiment are consolidated at the position of the pier beam consolidation point 3, and the bridge direction movable support 4 is used between the beam body 2 and the side pier. A discontinuous joint is arranged at the mid-span section, and the mid-span expansion device 6 is arranged at the discontinuous joint. When the beam body 2 deforms, for example, the beam body 2 elongates or shrinks due to temperature deformation caused by temperature rise and fall, the bridge direction expansion is realized at the mid-span section position through the mid-span expansion device 6, thereby reducing the length of the temperature span 5. By comparing Figure 1 and Figure 2 , it can be seen that the length of the temperature span 5 in the present embodiment is significantly smaller than the length L of the temperature span in the prior art.

[0021] As shown in Figure 3As shown, the beam body 2 comprises a bottom plate 7, a top plate 8 and a web plate (not shown as it is an elevation view), and the mid-span expansion device 6 is arranged on the bottom plate 7, the top plate 8 and the web plate, so as to ensure that the beam body 2 as a whole can realize expansion in the bridge longitudinal direction.

[0022] In combination Figure 4 and Figure 5 As shown, taking the direction of the drawing as an example, the top plate 8 of the beam body 2 is divided into a left top plate 10 and a right top plate 11 due to the setting of the joint. The mid-span expansion device 6 at the position of the joint comprises a right expansion member 12 and a left expansion member 14 as first and second expansion members respectively, wherein the right expansion member 12 is embedded in the right top plate 11 through a pre-embedded member, and the left expansion member 14 is embedded in the left top plate 10 through a pre-embedded member. The right expansion member 12 and the left expansion member 14 are of the same structure, both of which are provided with a bent buckle, and the buckles of the two are matched with each other to form a contact clamping, so that the right expansion member 12 and the left expansion member 14 can transmit bending moment and shear force after being tightly clamped. An upper expansion joint 13 is left between the right expansion member 12 and the left top plate 10, which can ensure the free displacement of the right expansion member 12 and the right top plate 11 in the bridge longitudinal direction. Similarly, a lower expansion joint 15 is left between the left expansion member 14 and the right top plate 11, which can ensure the free displacement of the left expansion member 14 and the left top plate 10 in the bridge longitudinal direction, and further ensure the deformation coordination between the top plate 8 as a whole and the ballastless track 9 arranged above the top plate 8.

[0023] As shown in the drawing, Figure 6 The bottom plate 7 is also divided into a left bottom plate 16 and a right bottom plate 17 by setting a joint, and a left expansion member 18 and a right expansion member 19 are arranged at the position of the joint, both of which transmit bending moment and shear force by mutual clamping. An upper expansion joint 21 is left between the right expansion member 19 and the left bottom plate 16; a lower expansion joint 20 is left between the left expansion member 18 and the right bottom plate 17, which ensures the free displacement of the expansion members and the beam body bottom plate in the bridge longitudinal direction.

[0024] Similarly, the same mid-span expansion device 6 as that arranged on the bottom plate 7 and the top plate 8 is arranged on the web plate of the beam body 2, which ensures the free displacement of the expansion members and the beam body as a whole in the bridge longitudinal direction.

[0025] In this embodiment, as shown in the drawing, Figure 3 The mid-span expansion devices 6 arranged on the bottom plate 7 and the top plate 8 are arranged on different elevations on both sides of the mid-span section center line of the beam body 2, so that the stress points of the beam body joint on both sides of the joint are in different planes, which ensures the structural performance of the beam body 2 and there is no weak point. Similarly, the mid-span expansion devices 6 arranged at the web plate position of the beam body are also on different elevations.

[0026] In comparison Figure 7 and Figure 8As shown, the embodiment cancels the fixed support between the main pier 1 and the beam body 2, and after consolidation, since the mid-span section of the beam body 2 can move along the bridge direction, the main pier 1 will not generate bending moment due to the deformation of the beam body 2, so the pier beam consolidation point 3 has no requirement on the height of the main pier 1, which is convenient for design and construction.

[0027] Comparison Figure 9 and Figure 10 As shown, the fixed position of the large-span concrete continuous beam in the prior art is extended to both sides from the fixed support position, and the temperature span length is from the fixed support to the beam end. In the embodiment, the beam body 2 can be extended to both sides from the main pier 1, and since the mid-span expansion device 6 is arranged in the mid-span section, the temperature span is divided into from the main pier 1 to the beam end or from the main pier 1 to the mid-span. In this way, the length of the temperature span is greatly shortened, and for a multi-span continuous beam, the effect will be more significant.

[0028] In the design and construction of the embodiment, the following steps are included: 1) According to the structure stress calculation, the size of the first expansion member and the second expansion member of the mid-span expansion device 6 is confirmed to ensure that the self bending and shearing strength of the first expansion member and the second expansion member are not less than the original structure strength, and there is no weak point in the member position.

[0029] 2) The beam body 2 and the main pier 1 are consolidated at the pier beam consolidation point 3 position, and the last section of the beam body 2 is suspended or cast in place, and the closing sections on both sides are reserved.

[0030] 3) The first expansion member or the second expansion member of the mid-span expansion device 6 is pre-buried on the bottom plate 7, the top plate 8 and the web of the beam body 2, and the two are clamped.

[0031] 4) Pour the concrete around the mid-span expansion device 6 (the first expansion member and the second expansion member), and stagger the reserved upper expansion joint and the lower expansion joint, complete the closing, and ensure that the bottom plate 7, the top plate 8 and the web and each mid-span expansion device 6 can change along the bridge direction, so as to realize the optimization of the temperature span of the large-span concrete structure continuous beam.

[0032] Although the above embodiment has made a detailed description of the concept and embodiment of the purpose of the present application with reference to the drawings, those skilled in the art can realize that various improvements and changes can be made to the present application without departing from the scope defined by the claims, and therefore, detailed description is not given here.

Claims

1. A design and construction method for a concrete bridge temperature span structure, comprising a main pier, side piers, and a beam, wherein the beam is supported on the main pier and side piers, the beam comprising a mid-span section and side span sections, and a ballastless track is disposed above the beam, characterized in that: The method provides a fracture in the mid-span section of a beam and a mid-span telescopic device at the position of the fracture, while consolidating the beam and the main pier, so that the beams on both sides of the fracture can freely displace along the bridge direction and the temperature span is from the main pier to the beam end or from the main pier to the mid-span; the mid-span telescopic device includes a first telescopic member and a second telescopic member, wherein the first telescopic member is embedded in the beam near the end face on one side of the fracture, and the second telescopic member is embedded in the beam near the end face on the other side of the fracture, and the first telescopic member and the second telescopic member are clamped together; an expansion joint is provided between the first telescopic member and the beam on the opposite side, and an expansion joint is provided between the second telescopic member and the beam on the opposite side.

2. The design and construction method of a concrete bridge temperature span structure according to claim 1 is characterized by: The bending and shearing strengths of the first telescopic member and the second telescopic member are not less than the structural strength of the beam body.

3. The design and construction method of a concrete bridge temperature span structure according to claim 1 is characterized by: During construction, the following steps are included: Consolidate the main pier and the beam body, and cast the beam body to the last section by cantilever casting or in-situ casting, leaving a closing section; The first telescopic member and the second telescopic member are correspondingly embedded in the top plate, the bottom plate and the web of the beam body, and the first telescopic member and the second telescopic member at corresponding positions are clamped together; Concrete is poured around each of the first telescopic members and the second telescopic members, and the reserved expansion joints are staggered to complete the closing.

4. The design and construction method of a concrete bridge temperature span structure according to claim 3 is characterized by: The mid-span telescopic device located on the top plate, the mid-span telescopic device located on the bottom plate and the mid-span telescopic device located on the web are arranged on different facades on both sides of the midline of the mid-span section.

5. The design and construction method of a concrete bridge temperature span structure according to claim 3 is characterized by: The first telescopic member and the second telescopic member are embedded in their respective corresponding beam bodies through embedded parts.

6. The design and construction method of a concrete bridge temperature span structure according to claim 1 is characterized by: A support that can move along the direction of the bridge is used between the beam body of the side span section and the side pier below it.

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