Steel-concrete composite structure bridge and construction method

Abstract

The application discloses a kind of steel-concrete composite structure bridge and construction method, the steel-concrete composite structure bridge includes upright combination beam section and cantilevered inverted combination beam section, cantilevered inverted combination beam section is connected with upright combination beam section by upright-inverted beam joint connecting section connection, cantilevered inverted combination beam section is set as upper steel box girder structure and lower concrete layer structure;The upper structure of upright combination beam is set as upper concrete layer structure and lower steel box girder structure, or, upright combination beam is full steel box girder structure.The steel-concrete composite structure bridge and construction method disclosed by the application, upright combination beam section is used to bear positive bending moment, inverted combination beam is used to bear negative bending moment, different structures are used to bear external force for the specific stress area of bridge, the anti-deformation ability of combination beam is increased, the problem that traditional steel-concrete composite beam is limited in negative bending moment area bridge deck slab cracking is solved, cantilevered inverted combination beam section does not need to tension prestress during cantilevered process, construction does not need to set up temporary pier, and construction is convenient.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering, and in particular to a steel-concrete composite structure bridge and its construction method. Background Technology

[0002] Composite beams are beams constructed by combining two different materials or processes; they are also known as combined beams. Traditional steel-concrete composite bridges typically consist of multiple channel steel or I-beams with a concrete deck above. They primarily utilize the advantages of both concrete (resisting compression) and steel box girders (resisting tension), making them cheaper than steel bridges and offering better load-bearing performance and easier construction than concrete structures. However, based on the structural characteristics and the location of steel and concrete within the cross-section, they are more suitable for beam segments subjected to positive bending moments. For beam segments with negative bending moments, the crack resistance of the bridge deck must be considered. The difficulty and cost of this design limit the application of composite beam bridges in continuous beam bridges.

[0003] Conventional steel-concrete composite beams are suitable for small- to medium-span bridges. To ensure that most of the internal forces are positive bending moments, the construction method is to complete the bridge in one go and then dismantle the scaffolding. For bridges with spans greater than 50m, due to limitations in the lifting capacity of the hoisting equipment, the construction process often involves constructing the steel box girder first, making the entire bridge continuous before constructing the bridge deck. This results in the steel box girder bearing the primary dead load, failing to fully utilize the advantages of composite beams, leading to low assembly efficiency, increased steel consumption, and higher costs. Moreover, the one-time dismantling construction method often requires the erection of temporary piers, which can impact traffic under the bridge, especially in areas crossing intersections or waterways, making construction more difficult.

[0004] Therefore, it is necessary to propose a steel-concrete composite bridge structure to address the aforementioned shortcomings. Summary of the Invention

[0005] The main objective of this invention is to provide a steel-concrete composite bridge and its construction method, aiming to solve the problems of suboptimal stress distribution and construction difficulties of existing composite beams under large span requirements.

[0006] To achieve the above objectives, the present invention provides a steel-concrete composite bridge structure, comprising upright composite beam segments and cantilevered inverted composite beam segments spliced ​​along the longitudinal direction of the bridge. The bridge abutment ends of the cantilevered inverted composite beam segments and the bridge abutment ends of the upright composite beam segments are connected by upright-inverted beam joint connecting segments.

[0007] The upper structure of the cantilevered inverted composite beam segment is configured as an upper steel box girder structure, and the lower structure of the cantilevered inverted composite beam segment is configured as a lower concrete layer structure; the upper structure of the upright composite beam is configured as an upper concrete layer structure, and the lower structure of the upright composite beam is configured as a lower steel box girder structure; alternatively, the upright composite beam is an all-steel box girder structure.

[0008] The upper steel box girder structure extends longitudinally towards the upright composite beam segment and protrudes beyond the end face of the lower concrete layer structure. The lower steel box girder structure extends longitudinally towards the cantilevered inverted composite beam segment and protrudes beyond the end face of the upper concrete layer structure. The upright composite beam segment and the cantilevered inverted composite beam segment are assembled longitudinally and cast in place between the upper and lower steel box girder structures to form a joint connecting section between the upright composite beam segment and the cantilevered inverted composite beam segment. Prestressed steel reinforcement groups arranged longitudinally are embedded within the joint connecting section.

[0009] The upper steel box girder structure extends longitudinally towards the end of the upright composite beam segment and protrudes beyond the end face of the lower concrete layer structure. The lower structure of the all-steel box girder structure extends longitudinally towards the end of the cantilevered inverted composite beam segment and protrudes beyond the end face of its upper structure.

[0010] The upright composite beam segment and the cantilever inverted composite beam segment are assembled along the longitudinal direction of the bridge and cast in place between the upper steel box girder structure and the lower structure of the all-steel box girder structure to form the upright-inverted beam joint connection segment for connection between the upright composite beam segment and the cantilever inverted composite beam segment. The upright-inverted beam joint connection segment is pre-embedded with prestressed steel reinforcement groups arranged along the longitudinal direction of the bridge.

[0011] Preferably, the upper steel box girder structure includes an upper steel box girder and a plurality of upper steel diaphragms disposed on the upper steel box girder. The upper steel diaphragms extend along the longitudinal direction of the bridge and protrude from the end face of the lower concrete layer structure. The plurality of upper steel diaphragms are arranged at intervals along the transverse direction of the bridge, and an upper steel compartment is formed between two adjacent upper steel diaphragms.

[0012] Each lower steel box girder structure includes a lower steel box girder and multiple lower steel diaphragms disposed on the lower steel box girder. The lower steel diaphragms extend longitudinally along the bridge direction and protrude from the end face of the upper concrete layer structure. The multiple lower steel diaphragms are arranged at intervals along the transverse direction of the bridge, and a lower steel compartment is formed between two adjacent lower steel diaphragms.

[0013] The positive and negative beam joint connection section is cast-in-place between the upper steel compartment, the upper concrete layer structure, the lower steel compartment, and the lower concrete layer structure, or...

[0014] The all-steel box girder structure includes multiple longitudinal steel diaphragms disposed on the lower structure of the steel box girder. The end faces of the multiple longitudinal steel diaphragms protrude from the end faces of the upper structure of the steel box girder and extend along the longitudinal direction of the bridge. The multiple longitudinal steel diaphragms are arranged at intervals along the transverse direction of the bridge, and a longitudinal steel compartment is formed between two adjacent steel diaphragms. The positive and negative beam joint connection section is cast in place between the longitudinal steel compartment and the lower concrete layer structure.

[0015] The prestressed steel reinforcement group passes through the upper steel compartment and the upper concrete layer structure, as well as the lower steel compartment and the lower concrete layer structure, simultaneously from both above and below along the longitudinal direction of the bridge.

[0016] The prestressed steel reinforcement group passes through the longitudinal steel compartment and the lower concrete layer structure along the longitudinal direction of the bridge.

[0017] Preferably, upper positioning plates are fixedly connected to the plurality of upper steel partitions, and the plurality of upper steel partitions are connected to each other by upper transverse reinforcing bars passing through the upper steel compartments in the transverse direction; lower positioning plates are fixedly connected to the plurality of lower steel partitions, and the plurality of lower steel partitions are connected to each other by lower transverse reinforcing bars passing through the lower steel compartments in the transverse direction; or

[0018] Longitudinal positioning plates are fixedly connected to the multiple longitudinal steel partitions, and the multiple longitudinal steel partitions are connected by transverse steel bars passing through the longitudinal steel compartments in the transverse direction.

[0019] Preferably, there are multiple cantilever inverted composite beam segments and multiple upright composite beam segments, and two adjacent cantilever inverted composite beam segments distributed along the longitudinal direction of the bridge are connected by the upright composite beam segments.

[0020] Preferably, the upper steel box girder structure and the lower concrete layer structure of the cantilevered inverted composite beam segment are connected by an inverted connection structure. The inverted connection structure includes a connecting plate, connecting reinforcing bars, and pre-embedded reinforcing bars embedded in the lower concrete layer structure. The connecting plate is connected to the bottom of the upper steel box girder structure, and the connecting reinforcing bars connect the pre-embedded reinforcing bars and the connecting plate together.

[0021] Preferably, the embedded reinforcing bars are in an inverted U-shape, and the connecting reinforcing bars pass through the connecting plate.

[0022] Preferably, the upper concrete layer structure and the lower steel box girder structure of the upright composite beam segment are connected by an upright connection structure, which includes a positioning plate whose end is connected to the bottom of the lower steel box girder structure and embedded in the upper concrete layer structure, and a through-bar reinforcement passing through the positioning plate.

[0023] A construction method for a steel-concrete composite bridge includes the following steps:

[0024] S1, At least one cantilevered inverted composite beam segment is erected using the cantilever construction method;

[0025] S2, the upright composite beam segment is joined to the cantilevered inverted composite beam segment;

[0026] S3, construct the joint connection section of the upright and inverted beams.

[0027] Preferably, step S1 includes the following steps:

[0028] S11, According to the design requirements, two piers of the aforementioned cantilevered inverted composite beam segments are pre-built;

[0029] S12, A bracket is erected on each of the piers and concrete is poured to form the lower concrete layer structure;

[0030] S13, hoist the steel box girder structure onto the lower concrete layer and connect it to the lower concrete layer structure.

[0031] Preferably, step S2 includes the following steps:

[0032] S21, Pre-fabricate the upright composite beam segment;

[0033] S22, hoist the upright composite beam segment and join the upright composite beam to the cantilevered inverted composite beam.

[0034] Compared with the prior art, the steel-concrete composite bridge and construction method provided by the present invention have the following beneficial effects:

[0035] The steel-concrete composite bridge and construction method provided by this invention splices upright composite beam segments and cantilevered inverted composite beam segments along the longitudinal direction of the bridge and connects them through upright-inverted beam joints. The upright composite beam segments bear positive bending moments, while the inverted composite beams bear negative bending moments. Different structures are used to bear external forces in specific stress areas of the bridge. The concrete of the cantilever segments is under compression, while the steel structure is under tension, increasing the deformation resistance and load-bearing capacity of the composite beams. This eliminates problems such as concrete cracking and steel structure instability, solving the problem of traditional steel-concrete composite beams being limited by bridge deck cracking in negative bending moment areas. Furthermore, the use of upright and cantilevered inverted composite beam segments allows for easier construction of the composite beams. During construction, after all the cantilevered inverted composite beam segments are constructed, upright composite beam segments can be constructed between adjacent cantilevered inverted composite beam segments. When constructing the upright composite beam segments, only hoisting is required. Compared with traditional prestressed concrete cantilever continuous beams or continuous rigid frames, the cantilevered inverted composite beam segment cantilever assembly process does not require prestressing tension, making construction convenient and eliminating the problem of prestress relaxation in the later stage. Compared with traditional steel-concrete composite beams or steel box girders, no temporary piers need to be erected, so it will not affect traffic under the bridge. At the same time, by reasonably setting up upright composite beam segments and cantilevered inverted composite beam segments, compared with the traditional pure steel beam structure bridges exceeding 100m, its cost is reduced, and the construction is more convenient, making it more practical in the market. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0037] Figure 1 This is a structural schematic diagram of a steel-concrete composite bridge embodiment one provided by the present invention;

[0038] Figure 2 for Figure 1 The cross-sectional view of I-I shown;

[0039] Figure 3 for Figure 1 The cross-sectional view of II-II shown;

[0040] Figure 4 for Figure 1 An enlarged view of the structure of part A shown below;

[0041] Figure 5 for Figure 2 An enlarged view of the structure of section C is shown below;

[0042] Figure 6 for Figure 3 An enlarged view of the structure of part D is shown below;

[0043] Figure 7 A construction flowchart for a steel-concrete composite structure bridge provided by the present invention;

[0044] Figure 8 This is one of the construction steps diagrams for a steel-concrete composite bridge.

[0045] Figure 9 This is the second diagram showing the construction steps for a steel-concrete composite bridge.

[0046] Figure 10 This is the third step in the construction process diagram for a steel-concrete composite bridge.

[0047] Figure 11 This is the fourth step in the construction process diagram for a steel-concrete composite bridge.

[0048] Figure 12 This is a schematic diagram of the structure of a steel-concrete composite bridge according to Embodiment 2 of the present invention;

[0049] Figure 13 for Figure 12 The cross-sectional view of Ⅲ-Ⅲ shown;

[0050] Figure 14 for Figure 12An enlarged view of the structure of part B is shown below;

[0051] Figure 15 for Figure 12 The 3D view of part B shown;

[0052] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0053] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0056] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0057] Example 1

[0058] Please refer to the attached document. Figure 1-3This invention provides a steel-concrete composite structure bridge, which includes a cantilevered inverted composite beam segment 3 and a normal composite beam segment 4. The bridgehead end of the cantilevered inverted composite beam segment 3 is connected to the bridgehead end of the normal composite beam segment 4 through a normal-inverted beam joint connection segment. The upper structure of the cantilevered inverted composite beam segment 3 is configured as an upper steel box girder structure 31, and the lower structure of the cantilevered inverted composite beam segment 3 is configured as a lower concrete layer structure 33. The upper structure of the normal composite beam is configured as an upper concrete layer structure 41, and the lower structure of the normal composite beam is configured as a lower steel box girder structure 43. By setting up cantilevered inverted composite beam segment 3, upright composite beam segment 4, and cantilevered inverted composite beam segment 3, splicing them along the longitudinal direction of the bridge and connecting them through the upright-inverted beam joint section, upright composite beam segment 4 is used to bear positive bending moment, and inverted composite beam segment 4 is used to bear negative bending moment. Different structures are used to bear external forces for specific stress areas of the bridge. The concrete of the cantilever segments is all under compression, and the steel structure is all under tension, which increases the resistance to deformation and greatly increases the load-bearing capacity of the bridge. There are no problems such as concrete cracking and steel structure instability. This solves the problem of bridge deck cracking in traditional steel-concrete composite beams limited by negative bending moment areas. At the same time, due to the setting of upright composite beam segment 4, the bridge deck is also affected by the inverted composite beam segment 4. Compared to traditional prestressed concrete cantilever continuous beams or continuous rigid frames, the cantilever inverted composite beam segment 3, with its slab splicing process, eliminates the need for prestressing tension during construction. This simplifies construction and avoids the problem of prestress relaxation later on. Furthermore, unlike traditional steel-concrete composite beams or steel box girders, it eliminates the need for temporary piers, thus avoiding disruption to traffic beneath the bridge. Moreover, by rationally designing the cantilever inverted composite beam segment 3 and the upright composite beam segment 4, the cost is reduced compared to traditional pure steel beam structures exceeding 100m, while also facilitating material construction and enhancing market practicality.

[0059] like Figure 2 and Figure 3 As shown, it should be noted that the upper structure of the cantilevered inverted composite beam segment 3 is configured as an upper steel box girder structure 31, and the lower structure is configured as a lower concrete layer structure 33. The upper structure of the upright composite beam segment 4 is configured as an upper concrete layer structure 41, and the lower structure is configured as a lower steel box girder structure 43. According to... Figure 1The stress analysis of the bridge shown illustrates that in the cantilevered inverted composite beam segment 3, which bears negative bending moment, the lower layer is subjected to tensile stress, while the upper layer is subjected to compressive stress. Due to the high deformability of the steel box girder, it can effectively withstand tensile stress, while the upper concrete layer has good compressive performance and will not crack under compression. Thus, the performance of the cantilevered inverted composite beam segment 3 is greatly improved. Meanwhile, in the upright composite beam segment 4, which bears positive bending moment, the upper layer is made of concrete, and the lower layer is made of steel box girder, resulting in the upper layer being subjected to compressive stress and the lower layer to tensile stress. Similarly, the lower steel box girder structure 43 of the upright composite beam segment 4 also bears tensile stress, while the upper concrete layer structure 41 bears compressive stress. Following the same principle, because the steel box girder has a large deformability and can effectively withstand tensile stress, while the concrete layer has good compressive performance and will not crack under compression, the performance of the upright composite beam segment 4 is greatly improved. Therefore, it utilizes the advantages of both concrete under compression and steel box girder under tension. In terms of cost, concrete is cheaper than structural steel, and in terms of construction technology, concrete construction is more... For convenience, the upper structure of the cantilevered inverted composite beam segment 3 is made of steel box girder and the lower structure is made of concrete, and the upper structure of the upright composite beam segment 4 is made of concrete and the lower structure is made of steel box girder. This fully utilizes the performance characteristics of the materials themselves. Under the premise of meeting the strength requirements, the span of the bridge can be greatly increased. The bridge can reach a span of 300m. It is suitable for continuous beam or continuous rigid frame bridges in large intersections, large rivers, canyons and other places. Not only are the bridge performance and span improved, but the cost is also cheaper and the construction is faster.

[0060] It should be noted that by reasonably setting the thickness of the concrete layer structure as the bottom slab of the bridge, the centroidal axis of the steel-concrete composite section is placed in a suitable position, so that the maximum compressive strength of the concrete and the maximum tensile strength of the steel are reached simultaneously under pure bending, thereby giving full play to the performance of the two materials.

[0061] In particular, it should be noted that, such as Figure 1 As shown, the cantilevered inverted composite beam segment 3 is a variable cross-section beam with a T-shaped cross-section. The beam height of the steel-concrete inverted variable cross-section composite beam is designed so that the design value of the internal force under the maximum internal force combination is less than the design value of the resistance. With different T-section positions and varying bending moment magnitudes, the beam height, concrete slab thickness, and steel plate thickness in the steel-concrete composite section of the cantilevered inverted composite beam segment 3 are rationally configured so that under bending moment, the maximum compressive strength of the concrete and the maximum tensile strength of the steel can simultaneously meet the structural resistance requirements and the internal forces generated by external loads. This fully utilizes the properties of both materials, leverages their advantages, and is more economical.

[0062] Specifically, based on factors such as stress, the following data can be referenced when designing the cantilevered inverted composite beam segment 3: (1) The height of the T-beam root is approximately 3-5 times the height of the end beam. (2) The thickness of the concrete layer at the T-beam root is approximately 2-4 times the thickness of the end bottom plate. (3) The thickness of the steel plate at the T-beam root is approximately 1.2-2 times that at the end.

[0063] Specifically, it should be noted that under the requirement of large spans, as the span increases further, the internal forces generated by the load will also increase further. Ordinary steel and concrete may not be able to meet the internal force requirements, necessitating beam heights and structural dimensions exceeding conventional limits, which significantly compromises both aesthetics and economy. To improve the strength of the upper concrete layer structure 41 and the lower concrete layer structure 33, the concrete material can be changed to ultra-high performance concrete (UHPC) to enhance the steel-concrete compatibility. Alternatively, the steel can be replaced with high-performance steel. With the improvement in material properties, the beam height and structural plate thickness can be reduced, thereby reducing self-weight and further improving the span capacity of the beam.

[0064] like Figure 4 As shown, the upper steel box girder structure 31 extends longitudinally towards the upright composite beam segment 4 and protrudes from the end face of the lower concrete layer structure 33. The lower steel box girder structure 43 extends longitudinally towards the cantilevered inverted composite beam segment 3 and protrudes from the end face of the upper concrete layer structure 41. The upright composite beam segment 4 and the cantilevered inverted composite beam segment 3 are assembled longitudinally and cast in place between the upper steel box girder structure 31 and the lower steel box girder structure 43 to form the upright-inverted beam joint connection segment between the upright composite beam segment 4 and the cantilevered inverted composite beam segment 3 for connection. Furthermore, the upright-inverted beam joint connection segment is pre-embedded with prestressed steel reinforcement groups arranged longitudinally to further enhance the connection performance of the upright composite beam segment 4 and the cantilevered inverted composite beam segment 3 and strengthen the resistance to shear stress.

[0065] In other words, from the cross-section of the beam segment, a portion of the end face of the upper steel box girder structure 31 protrudes towards the upper concrete layer structure 41, while a portion of the end face of the lower steel box girder structure 43 protrudes towards the lower concrete layer structure 33. The four form a concave-convex connection structure, which can effectively connect the cantilevered inverted composite beam segment 3 and the upright composite beam segment 4. When the cantilevered inverted composite beam segment 3 is subjected to negative bending moment and the upright composite beam segment 4 is subjected to positive bending moment, a very large shear force is generated at the connection of the beam segments. Therefore, the concave-convex connection structure formed by the upright and inverted beam joint connection segment greatly enhances the shear stress resistance of the beam segment connection.

[0066] Specifically, the upper steel box girder structure 31 includes an upper steel box girder 311 and a plurality of upper steel partitions 313 disposed on the upper steel box girder 311. The upper steel partitions 313 extend along the longitudinal direction of the bridge and protrude from the end face of the lower concrete layer structure 33. The plurality of upper steel partitions 313 are arranged at intervals along the transverse direction of the bridge, and an upper steel compartment 312 is formed between two adjacent upper steel partitions 313.

[0067] Each of the lower steel box girder structures 43 includes a lower steel box girder 431 and a plurality of lower steel partitions 433 disposed on the lower steel box girder 431. The lower steel partitions 433 extend along the longitudinal direction of the bridge and protrude from the end face of the upper concrete layer structure 41. The plurality of lower steel partitions 433 are arranged at intervals along the transverse direction of the bridge, and a lower steel compartment 412 is formed between two adjacent lower steel partitions 433.

[0068] like Figure 4 As shown, the positive-inverted beam joint connection segment is formed by cast-in-place between the upper steel compartment 312, the upper concrete layer structure 41, the lower steel compartment 412, and the lower concrete layer structure 33. Specifically, the upper steel compartment 312 and the upper concrete layer structure 41, and the lower steel compartment 412 and the lower concrete layer structure 33 are cast-in-place. Therefore, the upper steel compartment 313 and the lower steel compartment 412 form a concrete pouring space, which is poured simultaneously with the upper concrete layer structure 41 and the lower concrete layer structure 33, so that the upper steel box girder structure 31 and the upper concrete layer structure 41 are connected, and the lower steel box girder structure 43 and the lower concrete layer structure 33 are connected. In this way, the positive composite beam segment 4 and the cantilevered inverted composite beam segment 3 are connected as one, with good connection effect, which can effectively withstand the shear force between the positive and negative bending moment zones of the bridge and has high strength.

[0069] It should be noted that the number of the upper steel partition 313 and the lower steel partition 433 can be set according to the width of the steel box girder. Preferably, in this embodiment, the number of the upper steel partition 313 and the lower steel partition 433 is 9.

[0070] like Figure 5As shown, specifically in this embodiment, the upper steel box girder structure 31 and the lower concrete layer structure 33 of the cantilevered inverted composite beam segment 3 are connected by an inverted connecting structure 7. The inverted connecting structure 7 includes a connecting plate 71, connecting reinforcing bars 73, and embedded reinforcing bars 75 embedded in the lower concrete layer structure 33. The connecting plate 71 is connected to the bottom of the upper steel box girder 311, and the connecting reinforcing bars 73 connect the embedded reinforcing bars 75 and the connecting plate 71 together. The connecting reinforcing bars 73 effectively connect the embedded reinforcing bars 75 and the connecting plate 71, thereby firmly connecting the bottom plate formed by the lower concrete layer structure 33 and the upper steel box girder 311 together, improving the connection performance between the upper steel box girder structure 31 and the lower concrete layer structure 33, and strengthening the bridge's strength.

[0071] Specifically, the embedded reinforcing bars 75 are in an inverted U-shape, and the connecting reinforcing bars 73 pass through the connecting plate 71. The inverted U-shaped embedded reinforcing bars 75 facilitate the connection of the connecting reinforcing bars 73, and thus facilitate the connection between the lower concrete layer structure 33 and the upper steel box girder structure 31.

[0072] Understandably, when the upright composite beam segment 4 is joined between two adjacent cantilevered inverted composite beam segments 3, the upright composite beam segment 4 is located in the middle section of the bridge, which is referred to here as the mid-span beam segment E of the bridge.

[0073] like Figure 6 As shown, specifically, the upper concrete layer structure 41 and the lower steel box girder structure 43 of the upright composite beam segment 4 are connected by an upright connecting structure 8. The upright connecting structure 8 includes a positioning plate 81 whose end is connected to the bottom of the lower steel box girder structure 43 and embedded in the upper concrete layer structure 41, and a through steel bar 83 passing through the positioning plate 81, effectively connecting the upper concrete layer structure 41 and the lower steel box girder structure 43 together.

[0074] The positioning plates 81 are multiple, each vertically positioned on the lower steel box girder structure 43. The positioning plates 81 are spaced apart along the longitudinal direction of the bridge. Through-steel bars 83 pass through each positioning plate 81, connecting them into a single unit. The positioning plates 81 are welded to the lower steel box girder structure 43, and then concrete is poured to connect the steel box girder and the concrete into a single unit. The number of positioning plates 81 and the spacing between adjacent positioning plates 81 are determined according to the bridge design requirements.

[0075] like Figure 4As shown, multiple upper steel partitions 313 are fixedly connected to upper positioning plates 314, and the multiple upper steel partitions 313 are connected to each other by upper transverse reinforcing bars 315 passing through the upper steel compartments 312 in the transverse direction. Multiple lower steel partitions 433 are fixedly connected to lower positioning plates 414, and the multiple lower steel partitions 433 are connected to each other by lower transverse reinforcing bars 415 passing through the lower steel compartments in the transverse direction. Specifically, the upper positioning plates 314 connect and fix the upper steel partitions 313, and the upper transverse reinforcing bars 315 then pass through the upper steel partitions 313 to connect them. The lower positioning plates 414 connect and fix the lower steel partitions 433, and the lower transverse reinforcing bars 415 then pass through the lower steel partitions 433 to connect them. The upper positioning plate 314 and the upper positioning plate 414 can enhance the connection performance of the upper steel partition 313 and the lower steel partition 433, thereby improving the structural strength.

[0076] Furthermore, such as Figure 6 As shown, the upper steel box girder structure 31 includes a top plate 50, a top plate stiffening rib 51 and a T-shaped stiffening rib 55 provided on the top plate 50, and each stiffening rib effectively enhances the structural strength of the steel box girder 311.

[0077] The lower steel box girder 431 of the lower steel box girder structure 43 has the same structure as the upper steel box girder 311 of the upper steel box girder structure 31, and will not be described again here.

[0078] As a preferred embodiment of this example, Figure 1 As shown, the steel-concrete composite structure bridge includes two cantilevered inverted composite beam segments 3 and three upright composite beam segments 4. One upright composite beam segment 4 is located between the two cantilevered inverted composite beam segments 3, serving as the middle upright composite beam segment. The other two are located at the other ends of the two cantilevered inverted composite beam segments 3, serving as side span upright composite beam segments 41. The side span upright composite beam segments 41 connect to the cantilevered inverted composite beam segments 3. The method for constructing the side span beam segments F is as follows: first, erect the support frame for the side span cast-in-place section; then, assemble the side span upright composite beam segments 4; finally, close the side span; tension the prestressed tendons of the top and bottom plates of the steel box girder of the side span upright composite beam segment 4; and after closure, dismantle the support frame for the side span cast-in-place section. Under the premise of conforming to the bridge bending moment distribution, the addition of the side span upright composite beam segments 4 can further increase the span of the bridge. The side span upright composite beam segment 41 is completed by building a support frame. Specifically, after the cantilevered inverted composite beam segment 3 is completed, the side span cast-in-place support frame can be erected and the side span upright composite beam 41 can be assembled.

[0079] It is worth mentioning that, such as Figure 1As shown, to maximize the bridge span, multiple cantilevered inverted composite beam segments 3 and upright composite beam segments 4 are respectively provided. Adjacent cantilevered inverted composite beam segments 3 distributed along the longitudinal direction of the bridge are connected by upright composite beam segments 4. Alternatively, upright composite beam segments 4 and cantilevered inverted composite beam segments 3 can be arranged in an intersecting manner. By setting multiple cantilevered inverted composite beam segments 3 and upright composite beam segments 4, the length of the bridge can be greatly extended. This method is suitable for continuous beam or continuous rigid frame bridges with large spans (80-300m) spanning large intersections, large rivers, and canyons. It solves the problem that traditional bridges cannot exceed 100m due to cracking issues. During the hoisting and closure of the upright composite beam segment 4 between two cantilevered inverted composite beam segments 3, no temporary piers are required, and traffic under the bridge will not be affected.

[0080] Please refer to the reference. Figures 7 to 11 The present invention also provides a construction method for a steel-concrete composite bridge, comprising the following steps:

[0081] S1, at least one cantilevered inverted composite beam segment 3 is erected using a cantilever construction method. Specifically, this includes:

[0082] S11, according to design requirements, two piers for the aforementioned cantilevered inverted composite beam segment 3 are pre-constructed symmetrically. Specifically, the main piers and transition piers are constructed separately. Before constructing the main piers, a construction trestle and drilling platform are erected. After constructing the main piers, the transition piers are constructed. The construction of the bored pile foundations for the main piers and transition piers is completed, along with the construction of the cofferdam. The construction of the pier caps for the main piers and transition piers is then completed (e.g., ...). Figure 7 (As shown).

[0083] S12, scaffolding is erected on each of the aforementioned piers, and concrete is poured to form the lower concrete layer structure 33 of the corresponding cantilevered inverted composite beam segment. Specifically, using a tower crane, climbing formwork construction is carried out on the main piers. Scaffolding is erected on the main piers, and concrete layers 30 of blocks 0 and 1 are poured. Once the lower concrete layer structure 33 reaches 95% of its design strength and the concrete age is more than 7 days, the corresponding longitudinal prestressing, transverse prestressing, and vertical prestressing steel strands (such as...) are tensioned. Figure 12 (As shown). The bridge deck crane 20 is used for cantilever construction of the main beam. After the cantilever bridge deck crane is installed on the first beam segment, a pre-stress test is conducted, and the elastic deformation curve during pre-stressing is recorded to minimize inelastic deformation and obtain elevation control data (such as...). Figure 7 (As shown).

[0084] S13, hoist the upper steel box girder structure 31 onto the lower concrete layer and connect the upper steel box girder structure to the corresponding lower concrete layer structure 33. For each segment of the segmented symmetrical cantilevered inverted composite beam segment 3 of the main span, the construction procedure for each segment is as follows: move the bridge deck crane 20 to level the formwork, hoist the steel box girder above the concrete layer, connect the upper steel box girder structure and the lower concrete layer structure using shear keys, weld the web and top plate of the steel box girder, and complete the construction of one segment (e.g., ...). Figure 7 (As shown).

[0085] Repeat S13 until the cantilevered inverted composite beam segments 3 at both ends are completed (as shown in the image). Figure 8 and 9 (As shown).

[0086] S2, the upright composite beam segment 4 is joined to the cantilevered inverted composite beam segment 3. Specifically, this includes:

[0087] S21, the upright composite beam segment 4 is prefabricated. The connecting steel bar 73 passes through the connecting plate 71 and the embedded steel bar 75 to connect the connecting plate 71 and the embedded steel bar 75 together. Then the connecting plate 71 is welded to the web plate 57 of the steel box girder and the concrete layer 6 is filled.

[0088] S22, hoist the upright composite beam segment 4 and assemble the upright composite beam onto the cantilevered inverted composite beam. Specifically, transport the upright composite beam segment 4 as a whole to the bridge site by boat, hoist the upright composite beam segment 4 in the middle of the span, and lock it with a temporary locking device after docking at the first end. Check and adjust the docking position to meet the requirements. High-strength bolts are used to connect the stiffening ribs and steel diaphragms on the top plate, bottom plate, and web plate 57 (e.g., Figure 10 (As shown).

[0089] The steel-concrete composite section interface is connected using the aforementioned positive and negative beam joint connection section. The positive and negative beam joint connection section serves as an adjustment opening during closure. A 500mm gap is reserved in each of the concrete layer, bottom slab, and web of the steel box girder as an adjustment section. A gap of about 40mm is reserved at the joint of each stiffening rib and steel partition of the concrete layer, bottom slab, and steel box girder, and high-strength bolts are used for connection.

[0090] After the fourth segment of the composite beam in the middle of the span is accurately positioned, a suitable closure temperature is selected, and all high-strength bolts are tightened. Then, welding is performed on the concrete layers, bottom slab, steel box girder web, and patch sections at both ends. After welding is completed, temporary auxiliary works such as the construction tower crane and trestle are dismantled. Finally, a full-bridge load test is conducted, and the bridge is opened to traffic after meeting acceptance standards (e.g., ...). Figure 11 (As shown).

[0091] The construction method of the steel-concrete composite structure bridge involves first erecting the cantilevered inverted composite beam segment 3 using a cantilever construction method, then merging the upright composite beam segment 4 onto the cantilevered inverted composite beam, and finally constructing the joint connecting section between the upright and inverted beams. Compared with traditional prestressed concrete cantilever continuous beams or continuous rigid frames, the cantilevered inverted composite beam segment 3 does not require prestressing during the cantilever assembly process, making construction convenient and eliminating the problem of prestress relaxation in the later stages. Moreover, when constructing the upright composite beam segment 4, only hoisting is required. Compared with the construction of traditional steel-concrete composite beams or steel box girders, temporary piers do not need to be erected, and traffic under the bridge will not be affected.

[0092] Example 2

[0093] like Figures 12 to 15 As shown, the difference from Embodiment 1 is that the upright composite beam is an all-steel box girder structure.

[0094] The upper steel box girder structure 31a of the cantilever inverted composite beam segment 3a extends longitudinally towards the end of the upright composite beam segment 4a and protrudes from the end face of the lower concrete layer structure 33a. The lower structure of the all-steel box girder structure extends longitudinally towards the end of the cantilever inverted composite beam segment 3a and protrudes from the end face of its upper structure. The upright composite beam segment 4a and the cantilever inverted composite beam segment 3a are assembled longitudinally and cast in place between the upper steel box girder structure 31a and the lower structure of the all-steel box girder structure to form a joint connecting segment between the upright composite beam segment 4a and the cantilever inverted composite beam segment 3a. Furthermore, a prestressed steel reinforcement group 46a arranged longitudinally is pre-embedded in the joint connecting segment to further enhance the connection performance between the upright composite beam segment 4a and the cantilever inverted composite beam segment 3a and strengthen the resistance to shear stress.

[0095] Specifically, in this embodiment, the upper layer of the cantilevered inverted composite beam segment 3a is configured as an upper steel box girder structure 31a, and the lower layer is configured as a lower concrete layer structure 33a. The upright composite beam segment 4a is entirely configured as a steel box girder. The lower layer of the cantilevered inverted composite beam segment 3a, which bears negative bending moment, bears tensile stress, while the upper layer bears compressive stress. The upright composite beam segment 4a, which bears positive bending moment, is entirely composed of steel box girders. That is, the steel box girder bears both tensile and compressive stress simultaneously. This is to achieve a larger bridge span and also to reduce the beam height.

[0096] In this embodiment, the all-steel box girder structure includes multiple longitudinal steel diaphragms 44a disposed on the lower structure of the steel box girder. The end faces of the multiple longitudinal steel diaphragms 44a protrude from the end faces of the upper structure of the steel box girder and extend along the longitudinal direction of the bridge. The multiple longitudinal steel diaphragms 44a are arranged at intervals along the transverse direction of the bridge, and a longitudinal steel compartment 45a is formed between two adjacent steel diaphragms. The positive and negative beam joint connection section is cast in place between the longitudinal steel compartment 45a and the lower concrete layer structure 33a. The prestressed steel reinforcement group 46a passes through the longitudinal steel compartment and the lower concrete layer structure 33a along the longitudinal direction of the bridge. Specifically, the longitudinal steel diaphragms 44a are disposed on the bottom plate of the steel box girder.

[0097] Furthermore, longitudinal positioning plates 47a are fixedly connected to the plurality of longitudinal steel partitions 44a, and the plurality of longitudinal steel partitions 44a are connected together by transverse steel bars passing through the longitudinal steel compartments 45a in the transverse direction.

[0098] like Figure 14 and Figure 15 As shown, when the upright composite beam segment 4a is a pure steel box girder, that is, the lower layer of the upright composite beam segment 4a is not reinforced with concrete, the longitudinal steel partition 44a is only installed inside the steel box girder of the upright composite beam segment 4a. The joint connecting section of the upright and inverted beams is cast in place between the longitudinal steel partition 45a and the lower concrete layer structure 33a, so that the upright composite beam segment 4a and the cantilevered inverted composite beam segment 3a are connected as one unit.

[0099] The steel-concrete composite bridge and construction method provided by this invention features a cantilevered inverted composite beam segment 3, a normal composite beam segment 4, and the cantilevered inverted composite beam segment 3 spliced ​​along the longitudinal direction of the bridge and connected by a joint between the normal and inverted beams. The normal composite beam segment 4 is used to bear positive bending moment, and the inverted composite beam is used to bear negative bending moment. The concrete of the cantilever segments is all under compression, and the steel structure is all under tension. Different structures are used to bear external forces in specific stress areas of the bridge, increasing the resistance to deformation and greatly increasing the load-bearing capacity of the bridge. It eliminates problems such as concrete cracking and steel structure instability, solving the problem of traditional steel-concrete composite beams being limited by bridge deck cracking in the negative bending moment area. Because of the use of upright composite beam segment 4 and cantilevered inverted composite beam segment 3, the cantilevered inverted composite beam segment 3 does not require prestressing during the construction of the composite beam, compared to traditional prestressed concrete cantilever continuous beams or continuous rigid frames. This makes construction convenient and avoids the problem of prestress relaxation in the later stages. Compared to the construction of traditional steel-concrete composite beams or steel box girders, it does not require the erection of temporary piers and will not affect traffic under the bridge. At the same time, by reasonably setting up upright composite beam segment 4 and cantilevered inverted composite beam segment 3, the cost is reduced compared to the traditional pure steel beam structure bridges used for bridges exceeding 100m, and the construction is more convenient, making it more practical in the market.

[0100] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A steel-concrete composite structure bridge, characterized in that, It includes upright composite beam segments spliced ​​along the longitudinal direction of the bridge and cantilevered inverted composite beam segments. The bridge abutment ends of the cantilevered inverted composite beam segments are connected to the bridge abutment ends of the upright composite beam segments through upright-inverted beam joint connecting segments. The upper structure of the cantilevered inverted composite beam segment is an upper steel box girder structure, and the lower structure of the cantilevered inverted composite beam segment is a lower concrete layer structure; the upper structure of the upright composite beam is an upper concrete layer structure, and the lower structure of the upright composite beam is a lower steel box girder structure. One end of the upper steel box girder structure facing the upright composite beam segment extends longitudinally and protrudes beyond the end face of the lower concrete layer structure. One end of the lower steel box girder structure facing the cantilevered inverted composite beam segment extends longitudinally and protrudes beyond the end face of the upper concrete layer structure. The upright composite beam segment and the cantilevered inverted composite beam segment are assembled longitudinally and cast in place between the upper and lower steel box girder structures to form a joint connecting segment between the upright composite beam segment and the cantilevered inverted composite beam segment. Prestressed steel reinforcement groups arranged longitudinally are pre-embedded in the joint connecting segment; or The upright composite beam is an all-steel box girder structure. The upper steel box girder structure extends longitudinally towards the upright composite beam segment and protrudes from the end face of the lower concrete layer structure. The lower layer structure of the all-steel box girder structure extends longitudinally towards the cantilevered inverted composite beam segment and protrudes from the end face of its upper layer structure. The upright composite beam segment and the cantilevered inverted composite beam segment are assembled longitudinally and cast in place between the upper steel box girder structure and the lower layer structure of the all-steel box girder structure to form the upright-inverted beam joint connection segment for connection between the upright composite beam segment and the cantilevered inverted composite beam segment. The upright-inverted beam joint connection segment is pre-embedded with prestressed steel reinforcement groups arranged longitudinally.

2. The steel-concrete composite structure bridge according to claim 1, wherein The upper steel box girder structure includes an upper steel box girder and multiple upper steel diaphragms disposed on the upper steel box girder. The upper steel diaphragms extend along the longitudinal direction of the bridge and protrude from the end face of the lower concrete layer structure. The multiple upper steel diaphragms are arranged at intervals along the transverse direction of the bridge, and upper steel compartments are formed between adjacent two upper steel diaphragms. Each lower steel box girder structure includes a lower steel box girder and multiple lower steel diaphragms disposed on the lower steel box girder. The lower steel diaphragms extend longitudinally along the bridge direction and protrude from the end face of the upper concrete layer structure. The multiple lower steel diaphragms are arranged at intervals along the transverse direction of the bridge, and a lower steel compartment is formed between two adjacent lower steel diaphragms. The inverted beam joint connection section is formed by cast-in-place between the upper steel compartment, the upper concrete layer structure, the lower steel compartment, and the lower concrete layer structure. The prestressed steel reinforcement assemblies pass through the upper steel compartment and the upper concrete layer structure simultaneously from the top, and simultaneously from the bottom, along the longitudinal direction of the bridge. The all-steel box girder structure includes multiple longitudinal steel diaphragms disposed on the lower structure of the steel box girder. The end faces of the multiple longitudinal steel diaphragms protrude from the end faces of the upper structure of the steel box girder and extend along the longitudinal direction of the bridge. The multiple longitudinal steel diaphragms are arranged at intervals along the transverse direction of the bridge, and a longitudinal steel compartment is formed between two adjacent longitudinal steel diaphragms. The positive and negative beam joint connection section is cast in place between the longitudinal steel compartment and the lower concrete layer structure. The prestressed steel reinforcement group passes through the longitudinal steel compartment and the lower concrete layer structure along the longitudinal direction of the bridge.

3. The steel-concrete composite structure bridge according to claim 2, characterized by An upper positioning plate is fixedly connected to a plurality of upper steel partitions, and the plurality of upper steel partitions are connected to each other by upper transverse steel bars passing through the upper steel compartments in the transverse direction. A lower positioning plate is fixedly connected to a plurality of lower steel partitions, and the plurality of lower steel partitions are connected to each other by lower transverse steel bars passing through the lower steel compartments in the transverse direction. or Longitudinal positioning plates are fixedly connected to the multiple longitudinal steel partitions, and the multiple longitudinal steel partitions are connected by transverse steel bars passing through the longitudinal steel compartments in the transverse direction.

4. The steel-concrete composite structure bridge according to claim 1, characterized in that, There are multiple cantilever inverted composite beam segments and multiple upright composite beam segments, and adjacent two cantilever inverted composite beam segments distributed along the longitudinal direction of the bridge are connected by the upright composite beam segments.

5. The steel-concrete composite structure bridge according to claim 1, characterized in that, The upper steel box girder structure and the lower concrete layer structure of the cantilevered inverted composite beam segment are connected by an inverted connection structure. The inverted connection structure includes a connecting plate, connecting bars, and pre-embedded bars embedded in the lower concrete layer structure. The connecting plate is connected to the bottom of the upper steel box girder structure, and the connecting bars connect the pre-embedded bars and the connecting plate together.

6. The steel-concrete composite structure bridge according to claim 5, characterized in that, The embedded reinforcing bars are inverted U-shaped, and the connecting reinforcing bars pass through the connecting plate.

7. The steel-concrete composite structure bridge according to claim 1, characterized in that, The upper concrete layer structure and the lower steel box girder structure of the upright composite beam segment are connected by an upright connection structure. The upright connection structure includes a positioning plate whose end is connected to the bottom of the lower steel box girder structure and embedded in the upper concrete layer structure, and a through-bar reinforcement passing through the positioning plate.

8. A construction method for a steel-concrete composite bridge, characterized in that, The steel-concrete composite structure bridge applied to any one of claims 1-7 includes the following steps: S1, At least one cantilevered inverted composite beam segment is erected using the cantilever construction method; S2, the upright composite beam segment is joined to the cantilevered inverted composite beam segment; S3, construct the inverted beam joint connection section to connect the cantilevered inverted composite beam segment with the adjacent upright composite beam segment.

9. The construction method for a steel-concrete composite structure bridge according to claim 8, characterized in that, Step S1 is: S11, According to the design requirements, two piers of the aforementioned cantilevered inverted composite beam segments are pre-built; S12, erect brackets on each of the piers and pour concrete to form the lower concrete layer structure of the corresponding cantilevered inverted composite beam segment. S13, hoist the upper steel box girder structure onto the lower concrete layer and connect the upper steel box girder structure to the corresponding lower concrete layer structure.

10. The construction method for a steel-concrete composite bridge according to claim 8, characterized in that, Step S2 includes the following steps: S21, Pre-fabricate the upright composite beam segment; S22, hoist the upright composite beam segment and join the upright composite beam to the cantilevered inverted composite beam.

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