Pier top connecting structure of composite structure bridge based on steel and concrete and construction method

Abstract

The invention provides a pier top connecting structure of a composite structure bridge based on steel and concrete and a construction method. A cross beam pouring area is formed between the ends of every two adjacent standard simply-supported units, and end steel plates, second shear nails, second tooth keys and fourth bridge floor post-pouring areas are arranged on composite beams participating in butt joint in the standard simply-supported units; a plurality of second tooth keys are arranged on the end face, close to the cross beam pouring area, of the concrete rib plate, a fourth bridge deck post-pouring area is located at the end, close to the cross beam pouring area, of the bridge deck slab, an end steel plate is arranged at the end, close to the cross beam pouring area, of the steel beam, and a plurality of second shear nails are arranged on the face, away from the steel beam, of the end steel plate; reinforcing steel bars are arranged in the cross beam pouring area and the fourth bridge floor post-pouring areas of the two adjacent standard simply-supported units, and concrete is poured together in the cross beam pouring area to form a connecting cross beam. The problem that a traditional simply-supported variable continuous structure cannot adapt to system conversion between composite beams in a multi-material composite web form is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge engineering, and in particular to a pier top connection structure of a composite structure bridge based on steel and concrete and a construction method. Background Art

[0002] The application of steel-concrete composite beams in small and medium span prefabricated bridges is mainly a combination of welded steel beams and concrete (NC) bridge decks. The welded steel beams include steel lower flanges, steel webs and steel upper flanges. With the popularization of ultra-high performance concrete (UHPC), as an improvement on traditional technology, steel-UHPC composite beams have been gradually promoted and applied in recent years. However, conventional steel-UHPC composite beams also have defects such as insufficient material performance, large steel consumption and welding workload. In order to make full use of the excellent performance of steel and UHPC materials and further improve the economy and applicability of steel-UHPC composite beams, some new composite beam structures have been proposed. The patent application with publication number CN112391932A provides a steel-ultra-high performance concrete composite beam, and the patent application with publication number CN112342889A provides a prefabricated light composite beam bridge with a steel-UHPC composite web. The idea of ​​both is to use UHPC to bear the high pressure stress of the upper flange and the low tensile stress of the composite web, and use steel to bear the high tensile stress of the lower part. This type of structure is different from the traditional composite beam of steel beam and UHPC or NC bridge deck. The biggest feature is the application of steel-UHPC composite web, which makes full use of material properties and has broad application prospects. At the same time, during the assembly construction process of this structure, it was found that there is no new simple support to continuous structure to match it, so that the adjacent simple support structure can be converted into a continuous beam structure.

[0003] In the prior art, the patent application with publication number CN109082998A discloses that the overall prefabricated steel plate composite beam structure adopts a cast-in-place middle support beam to realize the continuous conversion of the pier top simple support, which is a common structural form of this type of steel plate composite beam structure. However, the existing simple support to continuous structure is for the traditional composite beam with a single steel web, which is not suitable for the new steel-UHPC composite web structure. First, due to the mechanical property limitations of ordinary concrete, the cast-in-place middle support beam of the patent application with publication number CN109082998A generally needs to reach a width of about 120cm, and the volume of on-site casting is large; secondly, a large number of stirrups and transverse steel bars are required to be configured inside, as well as multi-layer bridge deck longitudinal steel bars to meet the crack resistance of negative longitudinal bending moment. On-site construction personnel need to perform high-strength steel bar welding in the narrow space of the middle support beam; at the same time, the longitudinal steel bars of the bridge deck at the pier top are embedded in the prefabricated beams, which block the passage from the bridge deck to the inside of the middle support beam. Construction personnel often need to enter from the side, which poses a great safety risk. In addition, the strength of ordinary concrete is low, and the pier top is subjected to huge negative bending moment. The lower flange of the steel beam needs to transfer huge pressure to the concrete crossbeam at the middle support, which may cause damage to the crossbeam at the middle support. Therefore, the lower flange and part of the web of the steel beam of the two adjacent spans are generally extended and welded, and the pressure is directly transferred by the steel beam, which artificially causes the transverse discontinuity of the concrete bridge. The risk of high-altitude welding operation on site is relatively high, and it also makes the arrangement and installation of steel bars in a small space more difficult. Finally, for the π-shaped precast beam, there are four support points. According to the principle of determining a plane with three points, due to the construction errors of the precast beam, cap beam, and pad stone, it is very likely that the support will be empty, or the precast beam bridge deck will not be flat enough, resulting in difficulties in paving construction.

[0004] In summary, there is an urgent need for a pier top connection structure and a construction method for a composite structure bridge based on steel and concrete to solve the problems existing in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a pier top connection structure based on a composite structure bridge of steel and concrete, aiming to solve the problem that the existing simply supported to continuous structure cannot be applied between steel-UHPC composite beams, so that adjacent simply supported structures are converted into continuous beam structures. The specific technical solution is:

[0006] A pier top connection structure of a composite structure bridge based on steel and concrete, comprising:

[0007] A standard simply supported unit, wherein at least one composite beam is arranged in parallel in the transverse direction of the bridge, and two composite beams adjacent to each other in the transverse direction of the bridge are connected by a longitudinal wet joint; the composite beam comprises a bridge deck and a composite rib located on the bottom surface of the bridge deck, the composite rib comprises a concrete rib and a steel beam, and the concrete rib is located between the bridge deck and the steel beam;

[0008] A crossbeam casting area is formed between the ends of two adjacent standard simply supported units, and an end steel plate, a second shear nail, a second tooth key and a fourth bridge deck post-casting area are provided on the combined beams participating in the butt joint in the standard simply supported units; wherein a plurality of second tooth keys are provided on the end surface of the concrete rib plate close to the crossbeam casting area, the fourth bridge deck post-casting area is located at one end of the bridge deck close to the crossbeam casting area, the end steel plate is provided at one end of the steel beam close to the crossbeam casting area, and a plurality of second shear nails are provided on one surface of the end steel plate away from the steel beam;

[0009] A crossbeam steel frame is provided in the crossbeam casting area, and a post-casting area steel mesh is provided in the fourth bridge deck post-casting area of ​​two adjacent standard simply supported units; concrete is cast together in the crossbeam casting area and the fourth bridge deck post-casting area to form a connecting crossbeam in the crossbeam casting area.

[0010] Preferably, the cross beam reinforcement skeleton includes a cross beam lap reinforcement, a cross beam stirrup group, and a plurality of cross beam transverse reinforcements arranged at intervals around the inner side of the cross beam stirrup group; the cross beam stirrup group includes a plurality of cross beam stirrups arranged at intervals along the transverse bridge direction, and a single cross beam transverse reinforcement is arranged along the transverse bridge direction and overlapped with each cross beam stirrup;

[0011] The longitudinal distribution steel bars in the concrete ribs extend into the cross beam casting area, and the longitudinal distribution steel bars on both sides of the cross beam casting area are overlapped by cross beam overlap steel bars.

[0012] Preferably, a thickened area is provided at the bottom of one end of the bridge deck near the crossbeam casting area, and the thickened area includes a thickened transition section and a thickened section. Longitudinal steel bars of the thickened area are buried in the thickened area, one end of the longitudinal steel bars of the thickened area is overlapped with the longitudinal main bars of the bridge deck in the bridge deck, and the other end thereof extends into the crossbeam casting area; the longitudinal steel bars of the thickened areas on both sides of the crossbeam casting area are overlapped by crossbeam overlap steel bars.

[0013] Preferably, the post-casting area steel mesh includes a plurality of post-casting area longitudinal steel bars arranged at intervals along the transverse direction of the bridge and a plurality of post-casting area transverse steel bars arranged at intervals along the longitudinal direction of the bridge. The post-casting area longitudinal steel bars and the post-casting area transverse steel bars are overlapped, and both ends of the post-casting area longitudinal steel bars are overlapped with the longitudinal main bars of the bridge deck in the bridge deck on both sides of the crossbeam casting area.

[0014] Preferably, the shear bearing capacity verification method of the pier top connection structure is:

[0015] Calculate the shear capacity V of the second tooth key ku :

[0016]

[0017] Calculate the shear capacity V of the second shear stud su :

[0018]

[0019] Calculate the shear bearing capacity V of the pier top connection structure u :

[0020] V u =V ku +V su (3)

[0021] If the shear bearing capacity of the pier top connection structure V u If formula (4) is satisfied, the shear bearing capacity of the pier top connection structure is considered qualified:

[0022] γ 0 V d ≤0.9V u (4)

[0023] Where: f ck is the standard value of the axial compressive strength of concrete; f td A is the design value of the axial tensile strength of concrete; k is the shear surface area of ​​the second tooth key; M is the number of the second shear nails; A s is the cross-sectional area of ​​the second shear stud; E c is the elastic modulus of concrete; f cd is the design value of the axial compressive strength of concrete; f su is the minimum tensile strength of the second shear stud; 0 is the importance coefficient of the bridge structure; V d It is the shear design value of the pier top connection structure.

[0024] Preferably, when the beam casting area and the fourth bridge deck post-casting area are cast with concrete together, the bottom surface of the connecting beam is controlled to protrude from the bottom surface of the steel beam; and anchor bolts are pre-embedded at the bottom of the connecting beam when casting.

[0025] Preferably, the total length of the fourth bridge deck post-casting area of ​​the standard simply supported units on both sides of the pier top connection structure is not less than 0.1L, where L is the larger span of the two adjacent standard simply supported units at the pier support point;

[0026] The depth-to-height ratio D / H of the second tooth key is 1 / 3 to 1 / 2.

[0027] Preferably, the concrete rib plate includes a rib plate concrete layer and a rib plate steel bar skeleton located inside the rib plate concrete layer; the steel beam includes a steel bottom plate and a steel web plate arranged on the steel bottom plate, and the upper edge of the steel web plate is alternately provided with steel tenons and mortise holes along the longitudinal bridge direction, and the steel tenons and mortise holes are buried inside the lower end of the concrete rib plate;

[0028] The rib plate reinforcement skeleton includes the bottom layer of longitudinal reinforcement, the second bottom layer of longitudinal reinforcement, longitudinal distribution reinforcement, transverse short reinforcement and a vertical stirrup group; the vertical stirrup group includes lower open stirrups and upper open stirrups alternately arranged along the longitudinal bridge direction; wherein the lower open stirrups are arranged in a one-to-one correspondence with the steel tenons, the upper open stirrups are arranged in a one-to-one correspondence with the mortise, the steel tenons are inserted into the openings at the lower ends of the lower open stirrups, the lower ends of the upper open stirrups are placed in the mortise, and transverse short reinforcements are provided on both sides of the lower ends of the upper open stirrups; the bottom layer of longitudinal reinforcement is used to connect the lower ends of the lower open stirrups in the longitudinal direction, and the second bottom layer of longitudinal reinforcement is used to connect the lower ends of the upper open stirrups in the longitudinal direction; a plurality of longitudinal distribution reinforcements are arranged inside the vertical stirrup group along the vertical direction, and a single longitudinal distribution reinforcement passes through the alternately arranged upper open stirrups and lower open stirrups in the longitudinal direction;

[0029] The bottom layer of longitudinal steel bars, the second bottom layer of longitudinal steel bars and the longitudinal distribution steel bars all extend into the beam casting area.

[0030] Preferably, the bridge deck includes a bridge deck concrete layer and a bridge deck steel bar skeleton located inside the bridge deck concrete layer, the bridge deck steel bar skeleton includes an upper transverse steel bar group, a lower transverse steel bar group and a bridge deck longitudinal main bar; a plurality of bridge deck longitudinal main bars are arranged at intervals along the transverse direction of the bridge, the upper transverse steel bar group is located on the upper side of the bridge deck longitudinal main bars, the lower transverse steel bar group is located on the lower side of the bridge deck longitudinal main bars, and the upper ends of the lower open stirrups overlap the bridge deck longitudinal main bars.

[0031] The present invention also provides a construction method for the pier top connection structure of the composite structure bridge based on steel and concrete, comprising:

[0032] S1, prefabricate composite beams in the factory, and complete the construction of piers, cap beams and support pads at the bottom of the bridge at the same time;

[0033] S2. Temporary supports are set on both sides of the support pad stone, and the ends of the two composite beams involved in the butt joint are supported by the temporary supports respectively;

[0034] S3. Measure the elevations of the four corner points of the composite beam bridge deck and compare the measured elevations with the designed elevations to find out the errors;

[0035] S4. A jack is set on the cap beam to adjust the elevation of the composite beam, and after the composite beam is adjusted to the design elevation, the elevation of the temporary support is locked;

[0036] S5. Install the permanent support and anchor bolts, ensuring that the upper surface of the permanent support is in a horizontal state;

[0037] S6. Complete the installation and binding of the steel bars in the order of first constructing the crossbeam steel bar skeleton and then constructing the steel bar mesh in the post-casting area;

[0038] S7. Install the bottom casting formwork, requiring the upper surface of the bottom casting formwork at the permanent support to be flush with the upper surface of the permanent support;

[0039] S8, install the side casting formwork and close the mold;

[0040] S9, pouring concrete into the beam pouring area and the fourth bridge deck post-casting area, and performing maintenance after the pouring is completed;

[0041] S10, dismantle the bottom casting formwork, side casting formwork and temporary supports, and drop the composite beams onto the permanent supports to form a continuous structural system;

[0042] S11. Remeasure the elevations of the four corner points of the composite beam bridge deck.

[0043] The application of the technical solution of the present invention has the following beneficial effects:

[0044] (1) The present invention provides a new multi-material, multi-structure connection form for composite structure bridges of steel and concrete. The second tooth key and the second shear nail jointly bear the shear resistance of the pier top section, solving the problem that the traditional simply supported continuous structure cannot adapt to the composite beams with multi-material composite web forms, so that the adjacent simply supported structures are converted into continuous beam structures.

[0045] (2) The pier top connection structure of the present invention has the advantages of narrow beam width and small on-site casting volume. The beam width is only 1 / 3 to 1 / 2 of that of the traditional structure, which can greatly shorten the on-site working time.

[0046] (3) The present invention makes full use of the ultra-high compressive strength of UHPC concrete. The steel beam and the connecting crossbeam are connected by only the second shear nail. It is no longer necessary to butt-weld the steel webs and steel bottom plates of adjacent composite beams, thus achieving zero welding operations on site and greatly reducing the construction difficulty and safety hazards.

[0047] (4) The steel bars in the pier top connection structure of the present invention are simply arranged and are all overlapped and tied, which avoids the need for traditional structures to operate in a narrow space with dense steel bars, thereby ensuring the working environment and work quality.

[0048] (5) The pier top connection structure and construction method of the present invention can solve the difficulties in bridge deck paving construction caused by construction elevation errors, and the problem of uneven reaction force at the support point at the bottom of the composite beam due to the support being empty.

[0049] (6) In the pier top connection structure of the present invention, the cross beam casting area and the fourth bridge deck post-casting area are cast with concrete together to form a T-shaped structure, which can effectively solve the problem of easy cracking of the pier top bridge deck.

[0050] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0052] Figure 1 It is a longitudinal cross-sectional view of a composite structural bridge system based on steel and concrete according to the present invention;

[0053] Figure 2 yes Figure 1 Structural diagram of the composite beam;

[0054] Figure 3 yes Figure 2 Schematic diagram of the arrangement of the middle upper open stirrups and the lower open stirrups;

[0055] Figure 4 yes Figure 2 A partial cross-sectional view of the connection structure between the steel web and the concrete rib;

[0056] Figure 5 (a) Yes Figure 2 Schematic diagram of cross section of composite beam;

[0057] Figure 5 (b) Yes Figure 2 Strain distribution diagram in the cross section of the composite beam;

[0058] Figure 5 (c) Yes Figure 2 Stress distribution diagram in the cross section of the composite beam;

[0059] Figure 6 yes Figure 1 Schematic diagram of concrete pouring construction of the middle pier top connection structure;

[0060] Figure 7 yes Figure 1 Schematic diagram of the reinforcement arrangement of the middle pier top connection structure;

[0061] Figure 8 yes Figure 7 Top view of the reinforcement arrangement of the middle pier top connection structure;

[0062] Fig. 9 yes Figure 1 Schematic diagram of the end structure of the standard simply supported unit;

[0063] Fig.10 yes Fig. 9 Cross-sectional view of the longitudinal wet joint along the transverse direction;

[0064] Fig.11 yes Figure 1 Schematic diagram of the first structural form of the connection structure between the middle beams;

[0065] Fig.12 yes Fig.11 Cross-sectional view of the connecting structure between the middle beams along the transverse direction;

[0066] Fig.13 It is a schematic diagram of the first-view transportation state of the composite beam;

[0067] Fig.14 It is a schematic diagram of the second perspective of the transport state of the composite beam;

[0068] Fig.15 It is a schematic diagram of the second structural form of the beam connection structure of the present invention;

[0069] Fig.16 yes Fig.15 Cross-section of the connection structure between the middle beams;

[0070] Fig.17 yes Fig.15 Partial view of the connection structure between the middle beams;

[0071] Fig.18 It is a schematic diagram of a third structural form of the beam connection structure of the present invention;

[0072] Fig.19 yes Fig.18 Axonometric view of the composite beam in the beam-to-beam connection structure shown;

[0073] Fig. 20 It is a schematic diagram of a fourth structural form of the beam connection structure of the present invention;

[0074] Fig.21 yes Fig. 20 The schematic diagram of the structure of the beam connection structure shown is when no concrete is poured;

[0075] Among them, 100, composite beam; 110, bridge deck, 111, transverse main reinforcement of bridge deck, 112, longitudinal main reinforcement of bridge deck, 113, thickened transition section, 114, thickened section, 115, longitudinal reinforcement of thickened area; 120, composite rib, 121, concrete rib, 122, transverse short reinforcement, 123, steel bottom plate, 124, steel web, 125, lower open stirrup, 126, steel tenon, 127, mortise, 128, upper open stirrup, 129, longitudinal distribution reinforcement, 1210 , the bottom longitudinal reinforcement, 1211, the second bottom longitudinal reinforcement; 130, the transverse diaphragm; 200, the beam connection structure; 210, the connection plate 1, 211, the web splicing plate 1, 212, the bottom plate splicing plate 1, 213, the bolt assembly 1, 214, the vertical docking area 1, 215, the shear key groove 1; 220, the connection plate 2, 221, the web splicing plate 2, 222, the first bridge deck post-casting area, 223, the vertical docking area 2, 224, the shear key groove 2, 225, the bolt assembly 2, 2 26. Connecting rod; 230. Second bridge deck post-casting area; 231. First shear nail; 232. First beam post-casting area; 233. Vertical docking area three; 240. Third bridge deck post-casting area; 241. First tooth key; 242. Second beam post-casting area; 300. Pier top connection structure; 301. End steel plate; 302. Second shear nail; 303. Second tooth key; 304. Beam casting area; 305. Fourth bridge deck post-casting area; 306. Anchor bolt; 307. Post-casting area longitudinal reinforcement; 308. Transverse reinforcement in post-casting area, 309. Crossbeam lap reinforcement, 3010. Crossbeam stirrups, 3011. Crossbeam transverse reinforcement; 400. Longitudinal wet joints, 401. Sealing strips, 402. Wet joint casting area, 403. Transverse reinforcement at edge of bridge deck; 500. Transport vehicle, 501. Guard frame, 502. Pad, 503. Sleeper, 504. Hand winch; 600. Cap beam, 601. Jack, 602. Temporary support, 603. Support pad stone, 604. Permanent support. DETAILED DESCRIPTION

[0076] In order to facilitate the understanding of the present invention, the present invention will be described more fully below, and preferred embodiments of the present invention are provided. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0078] Embodiment 1:

[0079] See also Figure 1-Figure 12 , this embodiment provides a composite structure bridge system based on steel and concrete, including:

[0080] A composite beam 100, comprising a bridge deck 110 and a composite rib 120 located on the bottom surface of the bridge deck 110, wherein the composite rib 120 comprises a concrete rib 121 and a steel beam (not shown in the figure), wherein the concrete rib 121 is located between the bridge deck 110 and the steel beam, i.e., the concrete rib 121 and the bridge deck 110 are cast together with concrete to form a T-shaped structure, and the upper edge of the steel beam is connected to the lower end of the concrete rib 121;

[0081] A standard simply supported beam comprises a plurality of composite beams 100 arranged along the longitudinal direction of the bridge, and adjacent composite beams 100 are connected by an inter-beam connection structure 200;

[0082] The standard simply supported unit comprises a plurality of standard simply supported beams arranged along the transverse direction of the bridge and two adjacent standard simply supported beams are connected by a longitudinal wet joint 400;

[0083] Two standard simply supported units adjacent to each other upwardly on the longitudinal bridge are connected via the pier top connection structure 300 to form a continuous structural system.

[0084] The bridge structure system in this embodiment is applicable to a span of 16 to 50 m, which can cover the span range of traditional prefabricated hollow slabs, prefabricated T-beams, and prefabricated small box beams. The beam height-span ratio is 1 / 25 to 1 / 30, and the overall structure is light and high-performance.

[0085] like Figure 2 and Figure 4 As shown, the steel beam includes a steel bottom plate 123 and a steel web 124 disposed on the steel bottom plate 123, the two forming a T-shaped structure, and the upper edge of the steel web 124 (i.e., the side close to the concrete rib 121) is alternately provided with steel tenons 126 and mortises 127 along the longitudinal direction of the bridge. Figure 4 As shown, Figure 4 The gray area in the figure is the mortise 127, and the distance between two adjacent tenons 126 is e. x The height of the steel tenon (i.e. the depth of the mortise) is h D The steel tenon 126 and the mortise 127 are buried in the concrete at the lower end of the concrete rib 121, and the distance between the lower edge of the concrete rib 121 and the bottom edge of the mortise 127 is C D Preferably, the spacing e of the steel tenons is x Generally 150~500mm, height h D With spacing e x The ratio of the cutting shape is between 0.27 and 0.4, and the thickness of the steel tenon is related to the height h DThe ratio range is 0.08 to 0.5; the distance C between the bottom edge of the mortise 127 and the lower edge of the concrete rib 121 D It should be greater than 20mm. Under the same cutting shape, the spacing of the steel tenons does not affect the horizontal shear bearing capacity of the composite beam and is inversely proportional to the ductility.

[0086] Preferably, the bridge deck 110 includes a bridge deck concrete layer and a bridge deck steel reinforcement skeleton located inside the bridge deck concrete layer, the concrete rib 121 includes a rib concrete layer and a rib steel reinforcement skeleton located inside the rib concrete layer, the rib steel reinforcement skeleton is connected to the bridge deck steel reinforcement skeleton, and the bridge deck concrete layer and the rib concrete layer are cast together.

[0087] like Figure 2 As shown, the bridge deck reinforcement skeleton includes an upper transverse reinforcement group, a lower transverse reinforcement group and a bridge deck longitudinal main reinforcement 112; a plurality of bridge deck longitudinal main reinforcements 112 are arranged at intervals along the transverse direction of the bridge, the upper transverse reinforcement group is located on the upper side of the bridge deck longitudinal main reinforcement 112, the upper transverse reinforcement group includes a plurality of bridge deck transverse main reinforcements 111 arranged at intervals along the longitudinal direction of the bridge, the bridge deck longitudinal main reinforcement 112 is overlapped with the bridge deck transverse main reinforcement 111 in the upper transverse reinforcement group, and the bridge deck longitudinal main reinforcement 111 is connected to the bridge deck longitudinal main reinforcement 112 by the bridge deck longitudinal main reinforcement 112. 2 and the bridge deck transverse main reinforcement 111 in the upper transverse reinforcement group provide bending and crack resistance in the longitudinal and transverse directions respectively; the lower transverse reinforcement group is located at the lower side of the bridge deck longitudinal main reinforcement 112, and the lower transverse reinforcement group includes a plurality of bridge deck transverse main reinforcements 111 arranged at intervals along the longitudinal direction, and the bridge deck transverse main reinforcements 111 in the lower transverse reinforcement group are not overlapped with the bridge deck longitudinal main reinforcements 112, and the transverse bridge positive moment bending and crack resistance are provided by the bridge deck transverse main reinforcements in the lower transverse reinforcement group. The arrangement of the bridge deck steel skeleton in this embodiment can avoid the quality problem of concrete pouring caused by too dense steel bars in the thin plate. Due to the small thickness of the bridge deck, the arrangement of the bridge deck transverse main reinforcement 111 and the bridge deck longitudinal main reinforcement 112 generally adopts the method of dense distribution of fine bars, the diameter of the steel bars generally does not exceed 16mm, and the spacing is generally between 80 and 120mm.

[0088] Furthermore, the ribbed steel reinforcement skeleton includes the bottom longitudinal steel bars 1210, the second bottom longitudinal steel bars 1211, the longitudinal distribution steel bars 129, the transverse short steel bars 122 and the vertical stirrup group (not shown in the figure); the vertical stirrup group includes the lower open stirrups 125 and the upper open stirrups 128 arranged alternately along the longitudinal bridge direction, such as Figure 2 and Figure 3As shown, the lower open stirrup 125 and the steel tenon 126 are arranged in a one-to-one correspondence, the upper open stirrup 128 and the mortise 127 are arranged in a one-to-one correspondence, the steel tenon 126 is inserted into the opening at the lower end of the lower open stirrup 125, the lower end of the upper open stirrup 128 is placed in the mortise 127, and transverse short steel bars 122 are provided on both sides of the lower end of the upper open stirrup 128, and the transverse short steel bars 122 are spaced from the lower end of the upper open stirrup 128 (that is, the two are not overlapped, and the distance between the two in the longitudinal bridge upward is greater than 0), as shown in FIG. Figure 4 As shown; the position of the lower end of the lower open stirrup 125 is lower than the position of the lower end of the upper open stirrup 128, the bottom layer of longitudinal steel bars 1210 is used to connect the lower ends of each lower open stirrup 125 along the longitudinal direction, and the second bottom layer of longitudinal steel bars 1211 is used to connect the lower ends of each upper open stirrup 128 along the longitudinal direction. Specifically, in this embodiment, the number of the bottom layer of longitudinal steel bars 1210 and the second bottom layer of longitudinal steel bars 1211 are both two, and they are symmetrically arranged on both sides of the steel web 124; a plurality of longitudinal distribution steel bars 129 are arranged inside the vertical stirrup group along the vertical direction, specifically, a single longitudinal distribution steel bar 129 passes through the alternately arranged upper open stirrups 128 and lower open stirrups 125 along the longitudinal direction.

[0089] Specifically, the vertical sections of the upper open stirrups 128 and the lower open stirrups 125 can improve the shear resistance of the inclined section of the concrete rib, and the horizontal section at the lower end of the upper open stirrups 128 and the transverse short steel bars 122 can improve the anti-pushing ability of the steel tenons in the concrete rib, and the diameters of both need to be above 10 mm; the bottom layer of longitudinal steel bars 1210 and the second bottom layer of longitudinal steel bars 1211 are beneficial supplements to the bending crack resistance of the concrete rib 121 under positive bending moment, and their diameters should be above 12 mm, and the distance between the two in the height direction should be greater than 0.15 times the spacing of the steel tenons 126.

[0090] Preferably, the bridge deck concrete layer and the rib concrete layer are both cast using UHPC concrete, and the UHPC concrete is an ultra-high performance concrete having ultra-high durability and ultra-high mechanical properties.

[0091] Preferably, the lower end of the upper opening stirrup 128 in this embodiment is located at 1 / 2h D The upper end of the lower open stirrup 125 is connected to the bridge deck reinforcement skeleton, specifically, overlapped with the longitudinal main reinforcement 112 of the bridge deck.

[0092] Preferably, the lower end of the concrete rib 121 is thickened at the buried steel tenon 126 and the mortise 127 to ensure that the horizontal distance from the steel tenon to the edge of the concrete rib 121 is generally not less than 5 times the height of the steel tenon, thereby improving the fault tolerance of the centering error between the steel web 124 and the concrete rib 121, and at the same time providing bending space for the upper open stirrups and the lower open stirrups and reserving sufficient protective layer thickness for the stirrups, thereby improving the bonding ability of the steel web and the concrete rib 121.

[0093] Furthermore, in the composite beam 100 of the present embodiment, the number of composite ribs 120 is at least two. When the span of the composite beam is large, a diaphragm 130 (the diaphragm 130 is cast using UHPC concrete) may be provided between two adjacent concrete ribs 121. Fig.12 As shown, the diaphragm 130 can increase the structural stability of the composite beam. The composite beam 100 includes at least two composite ribs 120, so that the composite beam 100 has a self-stabilizing system (that is, the composite beam 100 can be placed stably through multiple composite ribs 120), which is convenient for the transportation and lifting of the composite beam 100. Of course, in some embodiments, it may not be required that the composite beam 100 has a self-stabilizing system. In this case, it is also feasible that a single composite beam 100 only includes one composite rib 120.

[0094] Preferably, the thickness of the concrete rib 121 is generally 12 to 20 cm. When the span of the bridge is large, the rib 121 can be thickened at the pier support. The concrete rib 121 is cast in the factory, and the height of the whole beam can be adjusted as needed to adapt to the change of the bridge span. At the same time, the pre-throw height of the continuous structure system can be set according to the calculation results and design requirements to offset the deformation of the beam under the dead load and part of the live load.

[0095] Preferably, the bridge deck can be a flat plate or a plate with transverse ribs for carrying vehicles. The thickness of a flat plate is generally 10 to 14 cm, and is used when the lateral spacing between adjacent concrete ribs 121 is not large; the thickness of a plate with transverse ribs is generally 8 to 12 cm, and the transverse ribs generally adopt an inverted T-shaped section, the height of the transverse ribs generally ranges from about 10 to 16 cm, and the spacing between the transverse ribs is 50 to 70 cm. The spacing between two concrete ribs 121 in the transverse direction of the bridge is generally 1.2m to 2.4m, which is usually determined based on the transverse bending resistance of the bridge deck under the action of the wheels and the angle for convenient transportation and lifting.

[0096] Preferably, the T-shaped steel beam can be cut from an H-shaped steel or welded from two steel plates. Preferably, the thickness of the steel bottom plate is 24-50 mm and the width is 200-600 mm. Preferably, the thickness of the steel web is 14-20 mm, and the ratio of its height to the height of the composite beam is generally 0.2-0.8 times, which needs to take into account the crack resistance of the lower edge of the concrete rib, the internal force arm of the cross section, and the production specifications of the H-shaped steel; the smaller the ratio of its height to the height of the composite beam, the smaller the internal force arm of the cross section, the lower the efficiency of the steel beam, and the greater the crack resistance risk faced by the lower end of the concrete rib.

[0097] like Figure 5 (a)- Figure 5 As shown in (c), the composite beam in this embodiment uses UHPC to bear the high pressure stress of the upper flange and the low tensile stress of the composite web, and uses the steel beam to bear the high tensile stress of the lower part, making full use of the material properties. The steel beam is far away from the neutral axis of the cross section and bears high tensile stress, which can greatly improve the positive moment bearing capacity of the structure. Because the steel beam is arranged outside the body, unlike the arrangement inside the body, its structure is not restricted by the concrete ribs, which can greatly increase the resistance moment of the internal force arm and flexibly configure the amount of steel material.

[0098] Preferably, Figures 6 to 9 As shown, the pier top connection structure 300 in this embodiment is specifically:

[0099] After two adjacent standard simply supported units are butt-jointed, a beam casting area 304 is formed between the ends of the two units, and an end steel plate 301, a second shear stud 302, a second tooth key 303 and a fourth bridge deck post-casting area 305 are provided on the composite beam 100 participating in the butt-jointing in the standard simply supported unit; wherein a plurality of second tooth keys 303 are provided on the end surface of the concrete rib plate 121 close to the beam casting area 304, the fourth bridge deck post-casting area 305 is located at one end of the bridge deck plate 110 close to the beam casting area 304, the end steel plate 301 is provided at one end of the steel beam close to the beam casting area 304, and a plurality of second shear studs 302 are provided on the side of the end steel plate 301 facing away from the steel beam;

[0100] A crossbeam steel skeleton is provided in the crossbeam casting area 304, and a post-casting area steel mesh is provided in the fourth bridge deck post-casting area 305 of two adjacent standard simply supported units. The crossbeam steel skeleton and the post-casting area steel mesh are overlapped with the composite beams on both sides; concrete (preferably UHPC concrete) is cast in the crossbeam casting area 304 and the fourth bridge deck post-casting area 305 together to form a connecting crossbeam in the crossbeam casting area 304, and the concrete cast in the fourth bridge deck post-casting area is flush with the upper surface of the bridge deck.

[0101] The pier top connection structure 300 in this embodiment can simultaneously realize the combined force transmission of the bridge deck and the combined rib 120, and utilizes a smaller thickness dimension and simplified steel bar connection to provide a reliable connection effect and integrity.

[0102] Specifically, Figure 7 As shown, the beam reinforcement skeleton includes beam lap reinforcement 309, a beam stirrup group and a plurality of beam transverse reinforcements 3011 arranged at intervals around the inner side of the beam stirrup group; the beam stirrup group includes a plurality of beam stirrups 3010 arranged at intervals along the transverse bridge direction in the beam casting area 304, and a single beam transverse reinforcement 3011 is arranged along the transverse bridge direction and overlapped with each beam stirrup 3010; the longitudinal distribution reinforcement 129 in the concrete rib 121 extends into the beam casting area 304, and the longitudinal distribution reinforcement 129 on both sides of the beam casting area 304 are overlapped by the beam lap reinforcement 309. Preferably, the horizontal spacing of the cross beam stirrups 3010 is generally 10 to 15 cm, and the arrangement should avoid the position of the combined rib 120 and meet the minimum protective layer thickness of UHPC; the spacing of the cross beam transverse reinforcement 3011 is generally 10 to 20 cm (this spacing refers to the vertical spacing or the longitudinal bridge spacing), and the second tooth key 303 and the second shear nail 302 should be avoided during arrangement.

[0103] Furthermore, the bridge deck 110 is provided with a thickened area at the bottom near one end of the beam casting area 304, and the thickened area includes a thickened transition section 113 and a thickened section 114. A thickened area longitudinal steel bar 115 is embedded in the thickened area, one end of the thickened area longitudinal steel bar 115 overlaps the bridge deck longitudinal main steel bar 112, and the other end extends into the beam casting area 304. The thickened area longitudinal steel bars 115 on both sides of the beam casting area 304 are also connected by the beam overlap steel bar 309. Preferably, the length of the thickened section 114 is generally 20-50 cm, and the length of the thickened transition section 113 is generally 50-100 cm. The thickening of the bridge deck and the thickened area longitudinal steel bars 115 are conducive to the transmission of force between the bridge deck and the connecting beam, and enhance the bending bearing capacity and crack resistance of the bridge deck.

[0104] Furthermore, the bottom longitudinal steel bars 1210 and the second bottom longitudinal steel bars 1211 in the concrete rib 121 also extend into the beam casting area 304; in this embodiment, no beam lap steel bars 309 are provided between the bottom longitudinal steel bars 1210 on both sides of the beam casting area and between the second bottom longitudinal steel bars 1211 on both sides. Figure 7 As shown; of course, this does not exclude the possibility that in some embodiments, beam lap reinforcement 309 may be provided between the bottom longitudinal reinforcement 1210 on both sides of the beam casting area and between the second bottom longitudinal reinforcement 1211 on both sides.

[0105] Specifically, Figure 7 and Figure 8 As shown, the post-casting area steel mesh includes a plurality of post-casting area longitudinal steel bars 307 arranged at intervals along the transverse direction of the bridge and a plurality of post-casting area transverse steel bars 308 arranged at intervals along the longitudinal direction of the bridge. The post-casting area longitudinal steel bars 307 and the post-casting area transverse steel bars 308 are overlapped, and both ends of the post-casting area longitudinal steel bars 307 are overlapped with the longitudinal main bars 112 of the bridge deck on the composite beams on both sides of the crossbeam casting area 304.

[0106] In this embodiment, the problem of easy cracking of the bridge deck in the negative bending moment area of ​​the pier top can be effectively solved based on the excellent tensile properties of the UHPC material. The surface layer post-casting interface is transferred to a position with a smaller negative bending moment through the fourth bridge deck post-casting area to improve the crack resistance of the bridge deck under the action of negative bending moment. Preferably, in order to further improve the crack resistance of the negative bending moment area, at least one post-casting area longitudinal steel bar 307 can be added between adjacent post-casting area longitudinal steel bars 307. Since the added post-casting area longitudinal steel bar 307 does not have a corresponding longitudinal main bar 112 of the bridge deck, it is only overlapped with the post-casting area transverse steel bar 308, that is, the crack resistance of the negative bending moment area is improved by arranging the steel bars densely in the post-casting area steel mesh. Specifically, the diameter and spacing of the post-casting area longitudinal steel bars 307 and the post-casting area transverse steel bars 308 are calculated and determined according to the bending bearing capacity of the negative bending moment area and the bending bearing capacity of the beam, respectively. The net distance of the steel bars should not be less than 1.5 times the nominal diameter of the steel bars, and should not be less than 2 cm.

[0107] See also Figure 6 and Figure 7 In this embodiment, when the beam casting area 304 and the fourth bridge deck post-casting area 305 are cast together with concrete, the bottom surface of the connecting beam is controlled to protrude from the bottom surface of the steel beam. Preferably, the bottom surface of the connecting beam protrudes from the bottom surface of the steel beam by 10-20 cm. Such a setting can adjust the accumulated elevation error of the composite beam and the cap beam during production and installation. Preferably, when the connecting beam is cast, an anchor bolt 306 is embedded at its bottom. The anchor bolt 306 is used to realize the installation and connection between the formed connecting beam and the permanent support 604.

[0108] Specifically, the end steel plate 301 is welded to the ends of the steel web and the steel bottom plate, and the height and width of the end steel plate 301 exceed the height of the steel web and the width of the steel bottom plate by at least 20 mm, respectively, to provide good welding conditions. The second shear nails 302 are welded to the end steel plate 301, and the size and spacing of the second shear nails 302 are determined according to shear calculations, and the spacing should not be greater than 20 cm, and the distance between the outermost second shear nails and the edge of the end steel plate is not less than 2.5 cm.

[0109] Preferably, the overlap length of the overlap connection in the pier top connection structure 300 is generally not less than 16 cm and not less than 10 d, where d is the diameter of the steel bar. Compared with the traditional welding connection, the overlap connection of the pier top connection structure 300 greatly simplifies the construction operation while providing reliable anchoring, avoiding welding operations in narrow spaces.

[0110] Preferably, the fourth bridge deck post-casting area 305 and the beam casting area 304 are cast with UHPC concrete to form a T-shaped structure. The thickness of the fourth bridge deck post-casting area 305 is generally 6-12 cm, and the total length of the fourth bridge deck post-casting area of ​​the standard simply supported units on both sides of the pier top connection structure is generally not less than 0.1L, where L is the larger span of the two adjacent standard simply supported units at the pier support point.

[0111] Preferably, see Figure 6 The depth-to-height ratio D / H of the second tooth key 303 is generally 1 / 3 to 1 / 2, and the key tooth depth D can generally be 5 cm; the second tooth key is prefabricated together with the concrete rib in the composite beam to avoid the loss of shear resistance of the UHPC connection interface due to discontinuous steel fibers, and staggered key teeth are formed in the cast-in-place connecting beam, which can effectively enhance the interface shear resistance.

[0112] Furthermore, in the pier top connection structure of this embodiment, the shear resistance of the joint interface is jointly undertaken by the second tooth key 303 and the second shear nail 302. The shear bearing capacity verification method of the pier top connection structure is:

[0113] Calculate the shear capacity V of the second tooth key ku , unit N:

[0114]

[0115] Calculate the shear capacity V of the second shear stud su , unit N:

[0116]

[0117] Calculate the shear bearing capacity V of the pier top connection structure u , unit N:

[0118] V u =V ku +V su (3)

[0119] If the shear bearing capacity of the pier top connection structure V u If formula (4) is satisfied, the shear bearing capacity of the pier top connection structure is considered qualified:

[0120] γ 0 V d ≤0.9V u(4)

[0121] Where: f ck is the standard value of the axial compressive strength of concrete, in MPa; f td A is the design value of the axial tensile strength of concrete, in MPa; k is the shear surface area of ​​the second tooth key, in mm 2 ; M is the number of the second shear studs; A s is the cross-sectional area of ​​the second shear stud, in mm 2 ; E c is the elastic modulus of concrete, in MPa; f cd is the design value of the axial compressive strength of concrete, in MPa; f su is the minimum tensile strength of the second shear stud, in MPa; 0 is the importance coefficient of the bridge structure; V d is the shear design value of the pier top connection structure, in N. The finite element software is used to calculate the maximum shear force of the interface under the ultimate bearing capacity state.

[0122] In the pier top connection structure in this embodiment, the width of the connecting beam (in the longitudinal direction of the bridge) is generally only 40 to 60 cm, and the width of the connecting beam is only about 1 / 3 to 1 / 2 of the width of the traditional beam, which reduces the volume of concrete during pouring construction and greatly reduces the amount of on-site work.

[0123] It should be noted that the pier top connection structure 300 in this embodiment can also be applied to a bridge composed of multiple standard simply supported beams arranged longitudinally (i.e., there is only one standard simply supported beam in the standard simply supported unit), or multiple composite beams arranged longitudinally, that is, the pier top connection structure 300 can be used to connect two adjacent standard simply supported beams in the longitudinal direction of the bridge or two adjacent composite beams in the longitudinal direction of the bridge. Furthermore, the pier top connection structure 300 in this embodiment can also be applied to composite beams of other structural forms, such as composite beams in which the steel beams are I-beams, and the ribs and bridge decks are cast with ordinary concrete.

[0124] This embodiment also provides a construction method of the pier top connection structure 300, comprising the following steps:

[0125] S1. Prefabricate the composite beam 100 in the factory, and simultaneously complete the construction of the pier, cap beam 600 and support cushion stone 603 at the lower part of the bridge; specifically, the second tooth key 303 is cast together with the concrete rib plate 121, and the end steel plate 301 and the second shear nail 302 are welded when the composite beam is prefabricated, the end steel plate 301 is welded to the end of the steel beam, and the second shear nail 302 is welded to the side of the end steel plate 301 facing the beam casting area 304; the cap beam 600 falls on the pier, and the support cushion stone 603 is installed on the cap beam 600;

[0126] S2. Temporary supports 602 are arranged on both sides of the support pedestal 603, and the ends of the two composite beams 100 involved in the butt connection are supported by the temporary supports 602 respectively; specifically, the temporary supports 602 are installed on the cap beam 600, the temporary supports 602 are located on the inner side of the span of the support pedestal, and the temporary supports are sand bucket temporary supports;

[0127] S3. Measure the elevations of the four corner points of the composite beam bridge deck and compare the measured elevations with the designed elevations to find out the errors;

[0128] S4. A jack 601 is arranged on the cap beam 600 to adjust the elevation of the composite beam. After the composite beam is adjusted to the design elevation, the elevation of the temporary support 602 is locked. Specifically, the elevation of the composite beam is adjusted by lifting or unloading the jack 601. The lifting force of the jack must be greater than or equal to 1 / 3 of the beam weight of the composite beam. The elevation adjustment range of the composite beam = the design elevation of the bridge deck - the thickness of the bridge deck pavement - the measured elevation of the precast beam. If the calculated value is positive, it will be lifted upward, and if it is negative, it will be reversed. Furthermore, the locking elevation of the temporary support 602 is equal to the measured elevation of the composite beam minus the measured beam height of the composite beam.

[0129] S5, installing the permanent support 604 and the anchor bolts 306, ensuring that the upper surface of the permanent support 604 is in a horizontal state; specifically, the permanent support 604 is arranged on the support pad stone 603, and in this step, the anchor bolts 306 should be installed and connected with the permanent support 604;

[0130] S6. Complete the installation and binding of the steel bars according to the construction sequence of the crossbeam stirrups 3010, the crossbeam transverse steel bars 3011 and the steel mesh in the post-casting area;

[0131] S7, install the bottom casting template, requiring the upper surface of the bottom casting template at the permanent support 604 to be flush with the upper surface of the permanent support 604, to ensure that the connecting beam can fall stably on the permanent support after casting;

[0132] S8, install the side casting formwork and close the mold;

[0133] S9, pouring concrete into the beam pouring area and the fourth bridge deck post-casting area, and performing maintenance after the pouring is completed;

[0134] S10, dismantle the bottom casting formwork, the side casting formwork and the temporary support 602, and drop the composite beam onto the permanent support to form a continuous structural system;

[0135] S11. Remeasure the elevations of the four corner points of the composite beam bridge deck.

[0136] The pier top connection structure 300 of this embodiment provides a structure and construction method for converting a standard simply supported beam into a continuous beam with adjustable installation errors, thereby solving the problems of empty supports, uneven reaction forces, and poor paving construction conditions.

[0137] See also Fig.10 Specifically, the longitudinal wet joint 400 is as follows: a wet joint casting area 402 is formed between the bridge decks 110 in two standard simply supported beams adjacent to each other in the transverse direction of the bridge, and a sealing strip 401 is provided between the bottoms of the two bridge decks 110, and concrete (preferably UHPC concrete) is cast into the wet joint casting area 402 to complete the construction of the longitudinal wet joint 400.

[0138] Preferably, the bridge deck transverse main reinforcement 111 in the upper transverse reinforcement group of the bridge deck 110 extends into the wet joint casting area 402, and the bridge deck transverse main reinforcement 111 in the upper transverse reinforcement group of two adjacent bridge decks are staggered in the longitudinal direction and have overlapping sections in the transverse direction. The length of the overlapping section should not be less than 10d, where d is the diameter of the reinforcement, that is, the bridge deck transverse main reinforcement of one bridge deck 110 is staggered and inserted into the gap between the bridge deck transverse main reinforcement of another bridge deck 110, thereby enhancing the transverse bending resistance of the bridge and avoiding circular reinforcement and welding operations in the narrow space of traditional joints.

[0139] Preferably, the end of the bridge deck near the longitudinal wet joint is thickened on the bottom surface, and a bridge deck edge transverse steel bar 403 is additionally provided. A plurality of bridge deck edge transverse steel bars 403 are arranged at intervals along the longitudinal direction of the bridge. One end of a single bridge deck edge transverse steel bar 403 is overlapped with the bridge deck transverse main reinforcement 111 in the upper transverse reinforcement group and the bridge deck transverse main reinforcement 111 in the lower transverse reinforcement group, and the other end thereof extends to the bottom of the wet joint casting area 402. The bridge deck edge transverse steel bars 403 in two adjacent bridge decks 110 are staggered in the longitudinal direction and have overlapping sections in the transverse direction. The length of the overlapping section should not be less than 10d, where d is the diameter of the steel bar. This enhances the bending resistance in the transverse direction of the bridge while avoiding circular reinforcement and welding operations in the narrow space of traditional joints.

[0140] Preferably, the bottom and upper parts of the wet joint casting area 402 are both arranged with bridge deck longitudinal main reinforcements 112 along the transverse intervals, wherein the bridge deck longitudinal main reinforcements 112 arranged at intervals in the upper part are overlapped with the bridge deck transverse main reinforcements 111 in the upper transverse reinforcement group, and the bridge deck longitudinal main reinforcements 112 arranged at intervals in the bottom part are overlapped with the bridge deck edge transverse reinforcements 403, thereby enhancing the longitudinal bending resistance of the bridge through the bridge deck longitudinal main reinforcements.

[0141] Preferably, in the longitudinal wet joint 400 of the present embodiment, the lower transverse steel bar group of the bridge deck 110 does not extend into the wet joint casting area 402. Such a configuration can prevent the steel bars in the wet joint casting area from being too dense and affecting the casting quality of concrete; however, it is not ruled out that in some embodiments, the bridge deck transverse main bars 111 in the lower transverse steel bar group of the bridge deck 110 may also be extended into the wet joint casting area 402 to increase the structural strength of the longitudinal wet joint.

[0142] The longitudinal wet joint 400 in this embodiment can realize the connection between two adjacent standard simply supported beams as a whole, and a sealing strip 401 is set between the bottoms of the two bridge decks 110. No formwork is required when pouring concrete in the wet joint casting area 402, thereby reducing the complexity of the longitudinal wet joint construction; preferably, in this embodiment, the sealing strip is made of foam padding, and the cross-section of the wet joint casting area 402 is a T-shaped structure.

[0143] Figure 11-Figure 12 The diagram illustrates a structural form of a beam connection structure 200: a connection plate 210 is provided on the butt end surface of the bridge deck 110, and a vertical butt area 214 is provided at the butt end of the steel web 124; the connection plates 210 of two adjacent composite beams 100 are connected by welding on the upper side and by a bolt assembly 213 on the lower side; the butt ends of the steel bottom plates 123 of two adjacent composite beams 100 and the vertical butt areas 214 of the two composite beams 100 are butt-jointed by a rigid connection method.

[0144] Further, such as Fig.11As shown, the steel web 124 is provided with a vertical docking area 214 at the docking end, and the vertical docking area 214 and the steel web 124 form an L shape. The steel web 124 and the vertical docking area 214 can be an integral structure (that is, they can be cut and formed by a piece of plate), or can be formed by welding two plates into an L shape; at the same time, the vertical docking area 214 is alternately provided with steel tenons 126 and mortises 127 along the vertical direction on the side close to the concrete rib 121, and the steel tenons and mortises of the vertical docking area 214 are embedded in the concrete on the vertical side of the concrete rib (that is, the steel tenons and mortises on the upper edge of the steel web are embedded in the concrete at the lower end of the concrete rib, and the steel tenons and mortises on the vertical docking area 214 are also embedded in the concrete on the vertical side of the concrete rib), so as to increase the connection strength between the vertical docking area 214 and the concrete rib 121.

[0145] Preferably, similar to the thickening arrangement at the lower end of the concrete rib, in this embodiment, a thickening arrangement is also made at the vertical side where the concrete rib and the vertical docking area 214 dock. For specific requirements for the thickening arrangement and the arrangement of the steel bars, please refer to the description of the lower end of the concrete rib.

[0146] Specifically, the number of the connecting plates 210 can be multiple, and the connecting plates 210 are connected to the longitudinal main reinforcement 112 of the bridge deck. The connecting plates 210 are embedded in the butt end surface when the bridge deck 110 is poured with concrete; further, the upper side of the connecting plate 210 is flush with the upper surface of the bridge deck 110, and the lower side thereof is protruding from the bottom surface of the bridge deck 110. The portion of the connecting plate 210 protruding from the bottom surface of the bridge deck 110 is provided with a connecting hole 1, such as Figure 11-Figure 12 shown.

[0147] Furthermore, the vertical docking area 214 and the docking end of the steel bottom plate 123 described in this embodiment are also provided with a plurality of connection holes 1. Specifically, the connection hole 1 in this embodiment is used for bolts to pass through to achieve a fastening connection between bolts and nuts. In this embodiment, the docking ends of the steel bottom plates 123 of the two composite beams 100 are connected by a bottom plate splicing plate 212 and a bolt assembly 213; the vertical docking areas 214 of the two composite beams 100 are connected by a web splicing plate 211 and a bolt assembly 213. Preferably, in order to increase the connection strength between the two steel bottom plate docking ends, the width of the steel bottom plate 123 can be increased as a whole or partially, so that more bolt assembly 213 rows along the longitudinal direction of the bridge can be set between the two steel bottom plate docking ends in the transverse direction of the bridge to enhance the connection strength. For example: when H-shaped steel is used to cut steel beams, since the width of the original steel base plate is often narrow, there is not enough space to arrange bolts and it is impossible to achieve longitudinal quick connection. In this case, two connecting plates with the same plane, thickness and transition chamfers as the steel base plate can be symmetrically welded on the original steel base plate with the steel web as the center to widen the steel base plate.

[0148] Preferably, in some embodiments, the butt ends of the steel bottom plates 123 of the two composite beams 100 and the vertical butt areas 214 of the two composite beams 100 may be connected by welding; based on the inter-beam connection structure 200 of the present embodiment, those skilled in the art may change and adjust the structural form of the rigid connection method.

[0149] like Fig.12 As shown, in the beam connection structure 200 of this embodiment, the adjacent two composite beams 100 are also quickly docked and positioned by a shear key groove 215 and a shear key 1 (not marked), specifically: a shear key groove 215 is provided on the docking end face of the bridge deck 110 of one composite beam, and a shear key 1 is provided on the docking end face of the bridge deck 110 of the other composite beam. When two adjacent composite beams 100 are connected, the shear key 1 is inserted into the shear key groove 215 and connected by structural adhesive, so that the two composite beams 100 are quickly positioned and docked, and the cooperation of the shear key groove 215 and the shear key 1 can also improve the shear resistance of the beam connection structure 200. Preferably, the shear key groove 215 and the shear key 1 are both arranged on the vertical center line of the concrete rib 121, 2 to 3 cm away from the top surface of the bridge deck 110, the depth of the shear key groove 215 is 3 to 5 cm, and the shear key 1 is matched with the shear key groove 215.

[0150] Preferably, the inter-beam connection structure 200 in this embodiment is generally arranged at a position with a small bending moment, and at the same time, combined with transportation requirements, the risk of tensile cracking of the bridge deck is reduced. Generally, for standard simply supported beams within 35m, the inter-beam connection structure is roughly set near the 3-point, and for beams within 50m, the inter-beam connection structure is generally set near the 4-point. The inter-beam connection structure can meet the requirements of fast and reliable connection under simple conditions on site, reduce the difficulty and cost of on-site construction, and greatly improve the splicing efficiency.

[0151] Furthermore, the structural dimensions of the composite beam can be adjusted according to the position of the composite beam in the bridge. For example, when the composite beam is located at different positions such as the mid-span, simply supported end, and continuous end, the thickness and density of the steel beams in the composite beam and the steel bars in the concrete ribs can be adjusted in a targeted manner. The adjustment of the structural dimensions of the composite beam can use the position of the connecting structure between beams as a distinguishing point to ensure the standardization of the entire composite beam.

[0152] This embodiment also provides a construction method of the bridge structure system, comprising the following steps:

[0153] A1. Complete the overall prefabrication construction of the composite beam 100 in the prefabrication factory;

[0154] A1.1. Making steel beams: Use intelligent numerically controlled laser or plasma to cut the H-shaped steel along the center line of the web into two symmetrical steel beams with steel tenons and mortises; or weld a flat steel plate and a steel plate with steel tenons and mortises cut into steel beams;

[0155] A1.2. Place the steel beam on the casting pedestal;

[0156] A1.3. Calculate the pre-throw height of the continuous structure system and adjust the formwork structure and steel bar cutting of the composite beam according to the pre-throw height requirements;

[0157] A1.4. Install the steel bars in the concrete ribs and bridge decks, including: upper open stirrups 128, lower open stirrups 125, longitudinal distribution steel bars 129, the bottom longitudinal steel bars 1210, the second bottom longitudinal steel bars 1211, transverse short steel bars 122, transverse main steel bars 111 of the bridge deck, longitudinal main steel bars 112 of the bridge deck, longitudinal steel bars 115 in the thickened area, and transverse steel bars 403 at the edge of the bridge deck, etc. In order to avoid floating bars and ensure the positioning of the steel bars, construction erection steel bars may be provided;

[0158] A1.5. Virtually assemble and adjust the composite beams and embedded parts of the same standard simply supported beam through 3D laser scanning;

[0159] A1.6. Install the bottom mold and side mold in sequence;

[0160] A1.7. Pour concrete and vibrate with a vibrator. The side formwork is vibrated with an attached vibrator, and the thickened part of the concrete rib is vibrated with an inserted vibrator. The bridge deck is leveled with a CNC adjustable track leveler to meet the requirements of the bridge deck surface after pre-casting.

[0161] A1.8. Moisture curing for 2 days, remove the side mold and bottom mold in turn; where: curing temperature ≥ 90°, curing humidity ≥ 95%, steam covering curing for 2 days;

[0162] A1.9. The composite beams are hoisted from the casting pedestal to the beam storage area. Each composite beam is sprayed with the serial number and production information QR code. The number of stored beams shall not exceed 2 layers. Sleepers and other isolation measures shall be set to provide reliable support.

[0163] A2. Use conventional logistics to deliver the composite beams to the construction site;

[0164] A2.1. According to the construction sequence on site, the corresponding numbered composite beams are hoisted from the beam storage area to the transport vehicle 500; specifically, Fig.13 and Fig.14 As shown, no more than 2 sections of composite beams are delivered at a time, and no more than 2 layers of composite beams are stacked. In order to protect the composite beam 100 during transportation, sleepers 503 are placed at the bottom of the composite beam 100, and protective pads 502 are set on both sides of the bridge deck. The composite beams at the bottom are also limited by guard frames 501. The upper and lower layers of composite beams are bound on the transport vehicle 500 by hand winches 504 to protect the composite beams from damage during transportation. In order to avoid large-scale transportation, reduce logistics costs, and improve efficiency and accessibility, the total height, width, and length of the vehicle and cargo shall not exceed 4 meters, 2.55 meters, and 18.1 meters, respectively, and the total mass shall not exceed 49 tons;

[0165] A2.2. Install signal lights and warning signs at the tail and sides of the composite beam;

[0166] A2.3、Shipping and delivery;

[0167] A3. Assembling standard simply supported beams, wherein adjacent composite beams 100 are connected by beam connection structures 200;

[0168] A3.1. Hang the composite beams that make up the standard simply supported beams on the temporary pedestal on site and accurately adjust the positions of the composite beams;

[0169] A3.2. Adopting the inter-beam connection structure 200 to realize the connection between adjacent composite beams, specifically:

[0170] 1) Install the bottom plate splicing plate 1 and the web plate splicing plate 2, and select 50% of the connection holes in the bottom plate splicing plate 1 and the web plate splicing plate 2 in the order of four corners first and then plum blossoms, and drive in rivets for temporary connection;

[0171] 2) driving a nail into the connection hole 1 of the connection plate 1 of the two composite beams for temporary connection;

[0172] 3) Weld the top of the connecting plate of the two composite beams; in order to prevent the temperature rise of the steel plate generated during welding from being transmitted to the bridge deck and causing cracks, absorbent wet cloth strips are used on the bridge deck on both sides of the welding position to cool down;

[0173] 4) Replace the rivets on the connection plate 1 with high-strength bolts and tighten them; replace the rivets on the bottom plate splicing plate 1 with high-strength bolts and tighten them; replace the rivets on the web splicing plate 2 with high-strength bolts and tighten them;

[0174] A3.3. Repeat step A3.2 to complete the installation and connection between the remaining composite beams in the standard simply supported beam to obtain a standard simply supported beam.

[0175] A4. Transport and install standard simply supported beams at the bridge site;

[0176] This embodiment provides different transportation and installation methods for areas with different transportation conditions. Specifically, the transportation and installation methods for mountainous and hilly areas and other areas with inconvenient ground transportation conditions are as follows:

[0177] A4.1a, The beam transporter transports the standard simply supported beam to the rear of the abutment and the tail of the bridge erecting machine;

[0178] A4.2a, the bridge erecting machine is supported on the abutment and 1# pier;

[0179] A4.3a. Use the crane and beam transporter in front of the bridge erecting machine to lift the standard simply supported beam and feed the beam forward slowly;

[0180] A4.4a. The crane behind the bridge erector replaces the beam transporter to lift the standard simply supported beam and continue to feed the beam;

[0181] A4.5a. After the standard simply supported beam reaches the designated position, it is dropped onto the temporary support;

[0182] A4.6a. Measure the installation error and accurately adjust the temporary support elevation using the jack;

[0183] A4.7a. Complete the installation of multiple standard simply supported beams in the transverse direction of the bridge;

[0184] A4.8a, the bridge erecting machine moves forward and is supported on the 1# and 2# bridge piers;

[0185] A4.9a, the beam transporter transports the standard simply supported beam to the tail of the bridge erecting machine through the installed standard simply supported beam;

[0186] A4.10a. Repeat the process of A4.3a-A4.7a to install the standard simply supported beam of the next span.

[0187] The transportation and installation methods for areas with good ground transportation conditions such as cities, suburbs, plains, etc. are as follows:

[0188] A4.1b, Use a trailer to transport the standard simply supported beam to the bottom of the bridge pier to be installed;

[0189] A4.2b. Two truck cranes are arranged at the bridge piers at both ends, and the standard simply supported beams are hoisted and dropped onto temporary supports by two truck cranes;

[0190] A4.3b, measure the installation error of the standard simply supported beam and accurately adjust the temporary support elevation by jack;

[0191] A4.4b. Repeat the process of A4.1b-A4.3b to install other standard simply supported beams.

[0192] A5. Construct the longitudinal wet joints between two adjacent standard simply supported beams and perform maintenance;

[0193] A6. Construct the pier top connection structure between two adjacent standard simply supported units according to steps S1-S11;

[0194] A7. Construct bridge deck pavement, railings and other ancillary facilities.

[0195] The construction method of the bridge structure system provides an intelligent manufacturing production method for composite beams, solving the problems of high-precision steel structure processing, steel bar positioning, pre-assembly, and pre-throwing height setting. The construction method provides a lightweight installation method for areas such as mountains and hills and other areas with inconvenient ground transportation conditions, as well as areas with good ground transportation conditions such as cities, suburbs, and plains, solving the shortcomings of conventional installation methods that require the installation of temporary piers, gantry cranes and other large temporary facilities, with low installation costs and strong terrain adaptability.

[0196] Embodiment 2:

[0197] Based on the bridge structure system in Example 1, this embodiment provides a second structural form of the beam connection structure 200, such as Figure 15-17 As shown, specifically:

[0198] The butt joint end of the bridge deck 110 is provided with a first bridge deck post-casting area 222, and the butt joint end face of the bridge deck 110 is provided with a connecting plate 220 within the range of the first bridge deck post-casting area 222, and the steel web 124 is provided with a vertical butt joint area 223 at the butt joint end; the connecting plates 220 of the two composite beams 100 are connected by a bolt assembly 225, and after the connection is completed, UHPC concrete is poured into the first bridge deck post-casting area 222; the vertical butt joint areas 223 of the two composite beams 100 and the butt joint ends of the steel bottom plates 123 of the two composite beams 100 are butt jointed by a rigid connection method.

[0199] Preferably, the first bridge deck post-casting area 222 in the present embodiment does not penetrate the bridge deck panel 110 in the depth direction thereof, and no formwork is required when the first bridge deck post-casting area 222 is subsequently cast.

[0200] Furthermore, the upper side of the second connecting plate 220 is flush with the upper surface of the bridge deck 110, and the lower side thereof is protruding from the bottom surface of the bridge deck 110, such as Fig.16 and Fig.17 The second connecting plate 220 is provided with a plurality of second connecting holes for installing the second bolt assembly 225. Furthermore, the second connecting plate 220 is specifically provided with second connecting holes at the portion protruding from the bottom surface of the bridge deck 110 and at the portion located at the first bridge deck post-casting area 222.

[0201] Preferably, the first bridge deck post-cast area 222 and the second connecting plate 220 are arranged in a one-to-one correspondence, and the first bridge deck post-cast area 222 and the second connecting plate 220 can be provided in plurality; the second connecting plate 220 is connected to the longitudinal main reinforcement 112 of the bridge deck (i.e., welded), and when the first bridge deck post-cast area 222 is subsequently cast, the portion of the second connecting plate 220 located in the first bridge deck post-cast area and the second bolt assembly 225 located in the first bridge deck post-cast area 222 are pre-embedded in the concrete.

[0202] Preferably, if the bolt assembly 225 is installed on the second connecting plate 220 and may interfere with the longitudinal main reinforcement 112 of the bridge deck, a connecting rod 226 can be used to transfer between the second connecting plate 220 and the longitudinal main reinforcement 112 of the bridge deck, so that the connection point of the longitudinal main reinforcement 112 of the bridge deck on the second connecting plate 220 is avoided from the bolt assembly 2, such as Fig.17 shown.

[0203] See also Fig.15 In this embodiment, the steel web 124 is provided with a second vertical docking area 223 at the docking end, and the second vertical docking area 223 and the steel web 124 form an L shape, wherein the steel web 124 and the second vertical docking area 223 can be an integral structure (that is, they can be cut and formed by a piece of plate), or can be formed by welding two steel plates into an L shape; at the same time, the second vertical docking area 223 is also provided with a steel tenon 126 and a mortise 127 on the side close to the concrete rib 121 (that is, the upper side of the steel web is connected to the lower side of the concrete rib, and the vertical side inside the second vertical docking area is connected to the vertical side of the end of the concrete rib) to increase the connection strength between the second vertical docking area 223 and the concrete rib 121. In this embodiment, Fig.15 For any part not clearly indicated in the vertical docking area 223, please refer to Fig.11 The vertical docking area 1 shown, the vertical docking area 2 in this embodiment is the same as the vertical docking area 1 in Example 1.

[0204] In this embodiment, the vertical docking area 223 is also provided with multiple connection holes 2. In this embodiment, the vertical docking areas 223 of the two composite beams 100 are connected by a web splicing plate 221 and a bolt assembly 225, and the butt ends of the steel bottom plates 123 of the two composite beams 100 are connected by welding.

[0205] In some embodiments, the vertical butt joint area 223 of two composite beams 100 may be connected by welding. Similarly, the butt ends of the steel bottom plates of the two composite beams 100 may be bolted by using a bottom plate splicing plate 2 and a bolt assembly 2 (when bolting, the steel bottom plate 123 may be widened at the butt end). Based on the beam connection structure 200 of this embodiment, those skilled in the art may change and adjust the structural form of the rigid connection method.

[0206] like Fig.16 As shown, in the beam connection structure 200 of this embodiment, two adjacent composite beams 100 are also quickly docked and positioned through a second shear key groove 224 and a second shear key (not marked), specifically: a second shear key groove 224 is provided on the docking end face of the bridge deck 110 of one composite beam, and a second shear key is provided on the docking end face of the bridge deck 110 of the other composite beam. When two adjacent composite beams 100 are connected, the second shear key is inserted into the second shear key groove 224 and connected by structural adhesive, so that the two composite beams 100 are quickly positioned and docked, and the cooperation of the second shear key groove 224 and the second shear key can also improve the shear resistance of the beam connection structure 200.

[0207] In the inter-beam connection structure of the present embodiment, the two connecting plates are rigidly connected by bolt connection, and concrete is poured into the post-casting area of ​​the first bridge deck after the bolt connection. The connection between the bridge decks has good integrity, which avoids heat generated by welding between the connecting plates and affects the connection between the connecting plates and the bridge deck (i.e., cracks).

[0208] Embodiment 3:

[0209] Based on the bridge structure system in Example 1, this embodiment provides a third structural form of the beam connection structure 200, such as Figure 18-Figure 19 As shown, specifically:

[0210] The butt end of the bridge deck 110 is provided with a second bridge deck post-cast area 230, and the steel web 124 is provided with a vertical butt end three 233, and the upper side of the vertical butt end three 233 is provided with a first shear nail 231; a first inter-beam post-cast area 232 is formed between the ends of two adjacent composite beams 100, and the bridge deck steel skeleton extends into the first inter-beam post-cast area 232, and the second bridge deck post-cast area 230 and the first inter-beam post-cast area 232 are cast with UHPC concrete together, and the first shear nail 231 is buried in the cast concrete; the vertical butt end three 233 of the two composite beams 100 and the butt ends of the steel bottom plates 123 of the two composite beams 100 are butt-jointed by a rigid connection method.

[0211] Specifically, Fig.19 As shown, in this embodiment, a vertical docking area three 233 is provided at the docking end of the steel web 124, and the vertical docking area three 233 and the steel web 124 form an L shape, wherein the steel web 124 and the vertical docking area three 233 can be an integral structure (that is, they can be cut and formed by a piece of plate), or can be welded by two steel plates to form an L shape, and at the same time, the vertical docking area three 233 is also provided with a steel tenon 126 and a mortise 127 on the side close to the concrete rib 121 (that is, the upper side of the steel web is connected to the lower side of the concrete rib, and the vertical side inside the vertical docking area three 233 is connected to the vertical side of the end of the concrete rib) to increase the connection strength between the vertical docking area three 233 and the concrete rib 121.

[0212] Preferably, in this embodiment, the outer vertical sides of the vertical butt joint areas 233 of the two composite beams 100 and the butt joint ends of the steel bottom plates 123 of the two composite beams 100 are butt jointed by welding.

[0213] In some embodiments, the vertical butt joint area three 233 of two composite beams 100 may also be bolted using a web splicing plate three and a bolt assembly three. Similarly, the butt joint ends of the steel bottom plates 123 of the two composite beams 100 may also be bolted using a bottom plate splicing plate three and a bolt assembly three (when bolting, the steel bottom plate 123 may be widened at the butt joint ends). Based on the inter-beam connection structure 200 of the present embodiment, those skilled in the art may change and adjust the structural form of the rigid connection method.

[0214] Preferably, the second bridge deck post-cast area 230 does not penetrate the bridge deck 110 in the depth direction thereof, and no formwork is required when pouring the second bridge deck post-cast area 230 .

[0215] In the beam connection structure of the present embodiment, a first shear nail 231 is arranged at the upper side of the vertical docking area three 233 and the first shear nail is subsequently buried in the newly poured concrete, which not only enhances the connection strength between the vertical docking area three 233 and the newly poured concrete, but also enhances the shear resistance; the bridge deck steel skeleton extends to the first inter-beam post-casting area 232, and the second bridge deck post-casting area 230 and the first inter-beam post-casting area 232 are cast with concrete together, and the connection between the two bridge decks has good integrity and high connection strength; a rigid connection method is used to realize the connection between the two vertical docking areas three 233 and the docking ends of the two steel bottom plates 123, and the connection is stable and reliable. When the rigid connection method adopted is welding, the subsequent maintenance workload can be greatly reduced.

[0216] Embodiment 4:

[0217] Based on the bridge structure system in Example 1, this embodiment provides a fourth structural form of the beam connection structure 200, such as Figure 20-21 As shown, specifically:

[0218] The butt end of the bridge deck 110 is provided with a third bridge deck post-casting area 240; a second inter-beam post-casting area 242 is formed between the ends of two adjacent composite beams 100, the bridge deck steel frame and the rib steel frame are extended into the second inter-beam post-casting area 242, and the end surface of the concrete rib 121 close to the second inter-beam post-casting area 242 is provided with a plurality of first tooth keys 241; the third bridge deck post-casting area 240 and the second inter-beam post-casting area 242 are cast with UHPC concrete together, and the butt ends of the steel webs 124 of the two composite beams 100 and the butt ends of the steel bottom plates 123 of the two composite beams 100 are butt-jointed by a rigid connection method.

[0219] Preferably, in this embodiment, the butt joints between the butt ends of the steel webs 124 of the two composite beams 100 and the butt joints between the steel bottom plates 123 of the two composite beams 100 are both butt jointed by welding.

[0220] In some embodiments, the butt ends of the steel webs 124 of two composite beams 100 may be bolted together using a web splicing plate four and a bolt assembly four. Similarly, the butt ends of the steel bottom plates 123 of two composite beams 100 may be bolted together using a bottom plate splicing plate four and a bolt assembly four (when bolting, the steel bottom plate 123 may be widened at the butt ends). Based on the inter-beam connection structure 200 of this embodiment, those skilled in the art may change and adjust the structural form of the rigid connection method.

[0221] Preferably, the third bridge deck post-cast area 240 does not penetrate the bridge deck panel 110 in the depth direction thereof, and no formwork is required when pouring the third bridge deck post-cast area 240 .

[0222] In the beam connection structure of this embodiment, the third bridge deck post-casting area and the second inter-beam post-casting area are cast with concrete together so that the two composite beams form a whole. The connection integrity between the two composite beams is optimal. The first tooth key can enhance the connection strength between the composite beam and the newly cast concrete, while also increasing the shear transmission efficiency of the interface and improving the shear bearing capacity of the section. The butt ends of the two steel webs and the butt ends of the two steel bottom plates are connected by a rigid connection method. The connection is stable and reliable. When the rigid connection method is welding, the subsequent maintenance workload can be greatly reduced.

[0223] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pier top connection structure based on a composite structure bridge of steel and concrete, characterized in that: include: A standard simply supported unit, wherein at least one composite beam (100) is arranged in parallel in a transverse direction of the bridge, wherein the composite beam (100) comprises a bridge deck (110) and a composite rib (120) located on the bottom surface of the bridge deck (110), wherein the composite rib (120) comprises a concrete rib (121) and a steel beam, wherein the concrete rib (121) is located between the bridge deck (110) and the steel beam; A crossbeam casting area (304) is formed between the ends of two adjacent standard simply supported units, and an end steel plate (301), a second shear stud (302), a second tooth key (303) and a fourth bridge deck post-casting area (305) are provided on the combined beam (100) participating in the butt connection in the standard simply supported unit; wherein a plurality of second tooth keys (303) are provided on the end surface of the concrete rib plate (121) close to the crossbeam casting area (304), the fourth bridge deck post-casting area (305) is located at one end of the bridge deck (110) close to the crossbeam casting area (304), the end steel plate (301) is provided at one end of the steel beam close to the crossbeam casting area (304), and a plurality of second shear studs (302) are provided on the side of the end steel plate (301) facing away from the steel beam; A crossbeam steel frame is provided in the crossbeam casting area (304), and a post-casting area steel mesh is provided in the fourth bridge deck post-casting area (305) of two adjacent standard simply supported units; concrete is cast in the crossbeam casting area (304) and the fourth bridge deck post-casting area (305) together to form a connecting crossbeam in the crossbeam casting area (304).

2. The pier top connection structure of the composite structure bridge based on steel and concrete according to claim 1 is characterized in that: The crossbeam reinforcement skeleton comprises a crossbeam lap reinforcement (309), a crossbeam stirrup group, and a plurality of crossbeam transverse reinforcements (3011) arranged at intervals along the inner side of the crossbeam stirrup group; the crossbeam stirrup group comprises a plurality of crossbeam stirrups (3010) arranged at intervals along the transverse bridge direction, and a single crossbeam transverse reinforcement (3011) is arranged along the transverse bridge direction and overlapped with each crossbeam stirrup (3010); The longitudinal distribution steel bars (129) in the concrete rib plate (121) extend into the cross beam casting area (304), and the longitudinal distribution steel bars (129) on both sides of the cross beam casting area (304) are overlapped by cross beam overlap steel bars (309).

3. The pier top connection structure of the composite structure bridge based on steel and concrete according to claim 2 is characterized in that: A thickened area is provided at the bottom of one end of the bridge deck (110) close to the cross beam casting area (304), and the thickened area includes a thickened transition section (113) and a thickened section (114). A thickened area longitudinal steel bar (115) is embedded in the thickened area, and one end of the thickened area longitudinal steel bar (115) is overlapped with the bridge deck longitudinal main steel bar (112) in the bridge deck (110), and the other end thereof extends into the cross beam casting area (304); the thickened area longitudinal steel bars (115) on both sides of the cross beam casting area (304) are overlapped by cross beam overlap steel bars (309).

4. The pier top connection structure of the composite structure bridge based on steel and concrete according to claim 1, characterized in that: The post-casting area steel mesh comprises a plurality of post-casting area longitudinal steel bars (307) arranged at intervals along the transverse direction of the bridge and a plurality of post-casting area transverse steel bars (308) arranged at intervals along the longitudinal direction of the bridge. The post-casting area longitudinal steel bars (307) and the post-casting area transverse steel bars (308) are overlapped, and two ends of the post-casting area longitudinal steel bars (307) are overlapped with the bridge deck longitudinal main bars (112) in the bridge deck (110) on both sides of the crossbeam casting area (304).

5. The pier top connection structure of the composite structure bridge based on steel and concrete according to claim 1, characterized in that: The shear bearing capacity verification method of the pier top connection structure is: Calculate the shear capacity V of the second tooth key ku : Calculate the shear capacity V of the second shear stud su : Calculate the shear bearing capacity V of the pier top connection structure u : V u =V ku +V su (3), If the shear bearing capacity of the pier top connection structure V u If formula (4) is satisfied, the shear bearing capacity of the pier top connection structure is considered qualified: γ0V d ≤0.9V u (4), Where: f ck is the standard value of the axial compressive strength of concrete; f td A is the design value of the axial tensile strength of concrete; k is the shear surface area of ​​the second tooth key; M is the number of the second shear nails; A s is the cross-sectional area of ​​the second shear stud; E c is the elastic modulus of concrete; f cd is the design value of the axial compressive strength of concrete; f su is the minimum tensile strength of the second shear stud; γ0 is the importance coefficient of the bridge structure; V d It is the shear design value of the pier top connection structure.

6. The pier top connection structure of the composite structure bridge based on steel and concrete according to claim 1, characterized in that: When the crossbeam casting area (304) and the fourth bridge deck post-casting area (305) are cast with concrete together, the bottom surface of the connecting crossbeam is controlled to protrude from the bottom surface of the steel beam; when the connecting crossbeam is cast, anchor bolts (306) are pre-embedded at its bottom.

7. The pier top connection structure of the composite structure bridge based on steel and concrete according to claim 1, characterized in that: The total length of the fourth bridge deck post-casting area of ​​the standard simply supported units on both sides of the pier top connection structure shall not be less than 0.1L, where L is the larger span of the two adjacent standard simply supported units at the pier support point; The depth-to-height ratio D / H of the second tooth key (303) is 1 / 3 to 1 / 2.

8. The pier top connection structure of a composite structure bridge based on steel and concrete according to any one of claims 1 to 7, characterized in that: The concrete rib (121) comprises a rib concrete layer and a rib steel reinforcement skeleton located inside the rib concrete layer; the steel beam comprises a steel bottom plate (123) and a steel web (124) arranged on the steel bottom plate (123); the upper edge of the steel web (124) is alternately provided with steel tenons (126) and mortises (127) along the longitudinal bridge direction; the steel tenons (126) and mortises (127) are buried inside the lower end of the concrete rib (121); The ribbed steel reinforcement skeleton comprises a bottom layer of longitudinal steel bars (1210), a second bottom layer of longitudinal steel bars (1211), longitudinal distribution steel bars (129), transverse short steel bars (122) and a vertical stirrup group; the vertical stirrup group comprises lower open stirrups (125) and upper open stirrups (128) arranged alternately along the longitudinal bridge direction; wherein the lower open stirrups (125) and the steel tenons (126) are arranged in a one-to-one correspondence, the upper open stirrups (128) and the mortise (127) are arranged in a one-to-one correspondence, the steel tenon (126) is inserted into the opening at the lower end of the lower open stirrup (125), and the upper open stirrups (128) are arranged in a one-to-one correspondence. The lower end of the upper open stirrup (128) is placed in the mortise (127), and transverse short steel bars (122) are provided on both sides of the lower end of the upper open stirrup (128); the bottom layer of longitudinal steel bars (1210) is used to connect the lower ends of the lower open stirrups (125) in the longitudinal direction, and the second bottom layer of longitudinal steel bars (1211) is used to connect the lower ends of the upper open stirrups (128) in the longitudinal direction; a plurality of longitudinal distribution steel bars (129) are arranged in the vertical direction inside the vertical stirrup group, and a single longitudinal distribution steel bar (129) passes through the upper open stirrups (128) and the lower open stirrups (125) arranged alternately in the longitudinal direction; The bottom layer of longitudinal steel bars (1210), the second bottom layer of longitudinal steel bars (1211) and the longitudinal distribution steel bars (129) all extend into the crossbeam casting area (304).

9. The pier top connection structure of the composite structure bridge based on steel and concrete according to claim 8, characterized in that: The bridge deck (110) includes a bridge deck concrete layer and a bridge deck steel bar skeleton located inside the bridge deck concrete layer, the bridge deck steel bar skeleton includes an upper transverse steel bar group, a lower transverse steel bar group and a bridge deck longitudinal main bar (112); a plurality of bridge deck longitudinal main bars (112) are arranged at intervals along the transverse direction of the bridge, the upper transverse steel bar group is located on the upper side of the bridge deck longitudinal main bars (112), the lower transverse steel bar group is located on the lower side of the bridge deck longitudinal main bars (112), and the upper end of the lower open stirrup (125) is overlapped with the bridge deck longitudinal main bars (112).

10. A construction method for a pier top connection structure of a composite structure bridge based on steel and concrete according to any one of claims 1 to 9, characterized in that: include: S1, prefabricate the composite beam (100) in the factory, and complete the construction of the pier, cap beam (600) and support pad stone (603) at the bottom of the bridge at the same time; S2, temporary supports (602) are arranged on both sides of the support pad stone (603), and the ends of the two composite beams (100) involved in the butt connection are supported by the temporary supports (602) respectively; S3. Measure the elevations of the four corner points of the composite beam bridge deck and compare the measured elevations with the designed elevations to find out the errors; S4. A jack (601) is arranged on the cap beam (600) to adjust the elevation of the composite beam, and after the composite beam is adjusted to the designed elevation, the elevation of the temporary support (602) is locked; S5. Install the permanent support (604) and the anchor bolts (306), ensuring that the upper surface of the permanent support (604) is in a horizontal state; S6. Complete the installation and binding of the steel bars in the order of first constructing the crossbeam steel bar skeleton and then constructing the steel bar mesh in the post-casting area; S7, installing the bottom casting template, requiring that the upper surface of the bottom casting template at the permanent support (604) is flush with the upper surface of the permanent support (604); S8, install the side casting formwork and close the mold; S9, pouring concrete into the beam pouring area and the fourth bridge deck post-casting area, and performing maintenance after the pouring is completed; S10, dismantling the bottom casting formwork, the side casting formwork and the temporary support (602), and dropping the composite beam onto the permanent support to form a continuous structural system; S11. Remeasure the elevations of the four corner points of the composite beam bridge deck.

Images