Construction method of permanent large-span platform layer structure

Abstract

The invention relates to the technical field of rail transit, in particular to a construction method of a permanent large-span platform layer structure, a steel truss system is assembled under the prefabrication working condition, the steel truss system is formed by splicing a plurality of Bailey steel sheets, and the transversely adjacent Bailey steel sheets are fixedly connected through a transverse splicing structure to form a whole; a profiled steel sheet bottom die is welded on a steel truss system through a shear connector, a steel bar truss is welded on the profiled steel sheet bottom die, then concrete is poured to form a steel bar truss floor support plate, and the steel bar truss floor support plate and the steel truss system are fixedly connected to form a platform layer structure prefabricated assembly section of an integral structure. The method has the advantages that the assembly degree is high, the quality is guaranteed, the construction speed is high, the problem of a large-span structure without columns in the middle can be solved, cast-in-place large-size components and a field complex tensioning process are not needed, and meanwhile the vibration influence of a train is reduced to a great extent; and the special-shaped steel member is directly connected with the composite floor, so that the integrality is better.

Description

Technical Field

[0001] This invention relates to the field of rail transit technology, and in particular to a construction method for a permanent, large-span platform structure. Background Technology

[0002] Currently, the main structural forms of the platform level of elevated stations are divided into frame-column structures and prestressed concrete structures. Among them, the frame-column structure is constructed on-site by manually erecting scaffolding before pouring concrete, which has a relatively long construction period and makes it difficult to guarantee the quality of concrete pouring. On the other hand, the prestressed concrete structure rests on the bridge cap beam, and the impact of train vibration is detrimental to the prestressed structure. Furthermore, the quality of on-site pouring is difficult to guarantee, and the construction period is also relatively long, especially in areas crossing rivers where the construction cost is very high. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of the prior art by providing a construction method for a permanent, large-span platform structure. This method employs a novel Bailey truss, whose member cross-sectional shape differs from that of ordinary Bailey steel sheets, making it more conducive to the connection with composite floor decking. This allows for the formation of an integrated prefabricated structural system, enabling the achievement of large-span crossing requirements, such as those for river sections.

[0004] The objective of this invention is achieved through the following technical solutions: A construction method for a permanent, large-span platform structure, characterized by the following steps: The steel truss system is assembled in a prefabrication condition. The steel truss system is composed of several Bailey steel sheets, and the horizontally adjacent Bailey steel sheets are connected and fixed to form a whole through a horizontal splicing structure. The bottom mold of the profiled steel sheet is welded onto the steel truss system through shear connectors, and the steel truss is welded onto the bottom mold of the profiled steel sheet. Then, concrete is poured to form a steel truss floor deck. The steel truss floor deck is fixedly connected to the steel truss system to form a prefabricated assembly section of the platform layer structure of the whole structure. The prefabricated assembly section of the platform layer structure is lifted and the support is fixedly installed at the corresponding position below the prefabricated assembly section of the platform layer structure. After leveling the prefabricated assembly section of the platform layer structure, the longitudinally adjacent Bailey steel sheets are connected and fixed to form an integral structure through a longitudinal splicing structure. After assembly, subsequent construction will be carried out on the steel truss floor slab.

[0005] The Bailey steel sheet includes an upper chord and a lower chord. A vertical web member is welded between the upper chord and the lower chord. An oblique web member is welded between the upper chord and the vertical web member and between the lower chord and the vertical web member. A welded joint connector is fixed at the welding joint position between the oblique web member and the vertical web member.

[0006] The node connectors include octagonal connectors and hexagonal connectors. The octagonal connectors are clamped at the intersection of the diagonal web members and vertical web members in the middle of the Bailey steel sheet, and the hexagonal connectors are clamped at the intersection of the diagonal web members and vertical web members at both ends of the Bailey steel sheet.

[0007] A female connector is provided at one end of the Bailey steel sheet, and a male connector is provided at the other end. The female connector has a groove that is adapted to the male connector. The male connector is snapped into the groove. The female connector and the male connector are provided with pin holes, and the two are fixedly connected by a pin that passes through the pin hole.

[0008] The transverse splicing structure includes transverse angle steel bracing and diagonal angle steel bracing. The transverse angle steel bracing is arranged horizontally, and its two ends are respectively welded to two adjacent transverse Bailey steel sheets. The diagonal angle steel bracing is arranged diagonally, and its two ends are respectively welded to two adjacent transverse Bailey steel sheets.

[0009] A strip steel plate is welded and fixed together on the top surface of several horizontal Bailey steel sheets, and the steel truss floor deck rests on the strip steel plate.

[0010] The shear-resistant connector is a stud. The bottom mold of the profiled steel sheet rests on the strip steel sheet, and the stud penetrates the bottom mold of the profiled steel sheet and is welded to the strip steel sheet and the Bailey steel sheet.

[0011] The advantages of this invention are: 1) Compared with cast-in-place concrete structures, the present invention has a high degree of assembly, is processed into prefabricated components in the factory, has guaranteed quality, and has a fast construction speed, which can solve the problem of large-span structures without intermediate columns.

[0012] 2) Compared with prestressed concrete components, the processing flow of the present invention is simple, eliminating the need for on-site casting of large-volume components and complex on-site tensioning processes, while also greatly reducing the impact of train vibration.

[0013] 3) This invention can solve the problems of lightweight design and complex construction process of platform layer in long-span bridge-type elevated stations. Especially in areas that cross river sections, it can realize the construction process without cofferdams and without support in the river, which greatly saves the cost of construction measures.

[0014] 4) Compared with ordinary temporary Bailey structures, this is the first time that irregular steel components are directly connected to composite floor slabs. There is no need for crossbeams or other components in the middle, resulting in better overall integrity and easier overall prefabrication, thus realizing a permanent large-span platform structure. Attached Figure Description

[0015] Figure 1 This is an isometric view of a Bailey steel sheet in this invention; Figure 2This is a schematic diagram of the cross-sectional structure of the upper chord of the Bailey steel sheet in this invention; Figure 3 This is a schematic diagram of the cross-sectional structure of the lower chord of the Bailey steel sheet in this invention; Figure 4 This is a schematic diagram of the cross-sectional structure of the inclined web members and vertical web members of the Bailey steel sheet in this invention; Figure 5 This is a schematic diagram of the structure of the connecting plate at the middle node of the Bailey steel sheet in this invention; Figure 6 This is a schematic diagram of the structure of the Bailey steel sheet end node connecting plate in this invention; Figure 7 This is an isometric view of the female connector at the end of the Bailey steel sheet in this invention; Figure 8 This is an isometric view of the male connector at the end of the Bailey steel sheet in this invention; Figure 9 This is a schematic diagram of the cross-sectional structure of the two Bailey steel sheets connected by a support in this invention; Figure 10 This is a schematic diagram of the cross-sectional structure of the steel truss floor deck in this invention; Figure 11 This is a schematic diagram of the cross-sectional structure of the space truss platform layer in this invention; Figure 12 This is a schematic diagram of the longitudinal section of the connection between the Bailey truss and the floor deck in this invention. Figure 13 This is a schematic diagram of the cross-sectional structure of the connection between the Bailey truss and the floor deck in this invention. Detailed Implementation

[0016] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art: like Figure 1-13 As shown in the figure, the markings represent: 1. Upper chord, 2. Lower chord, 3. Diagonal web member, 4. Vertical web member, 5. Octagonal connecting plate, 6. Hexagonal connecting plate, 7. Female joint, 8. Male joint, 9. Angle steel transverse brace, 10. Angle steel diagonal brace, 11. Truss system, 12. Strip steel plate, 13. Profiled steel sheet bottom mold, 14. Stud, 15. Platform door railing, 16. Concrete bridge pier.

[0017] Example: Figures 1 to 13 As shown, the construction method of the permanent large-span platform structure in this embodiment includes three parts: a steel truss system, a bridge deck system, and shear connectors. The steel truss system is used to connect the bridge deck system and the concrete piers, and to provide stable support for the bridge deck system. The shear connectors are set between the steel truss system and the bridge deck system to strengthen the connection between the two and make them form an integral structure.

[0018] Combination Figure 1 and Figure 2 As shown, in this embodiment, the upper chord 1 of the Bailey steel sheet is made of π-type hot-rolled steel. The surface of the steel must be polished to remove stains and rust. First, a layer of primer is applied, then a layer of anti-corrosion paint is applied on the outside of the primer, and then a layer of fire retardant paint is applied on the outside of the anti-corrosion paint. The fire retardant paint is a non-expanding type fire retardant paint. The length of the upper chord 1 is generally based on a 6-meter module and cannot be interrupted in the middle.

[0019] Combination Figure 1 and Figure 3 As shown, the lower chord 2 of the Bailey steel sheet adopts an inverted π-shaped hot-rolled steel section, which is opposite to the upper chord 1. The surface of this steel section must also be ground to remove stains and rust. First, a layer of primer is applied, then a layer of anti-corrosion paint is applied on the outside of the primer, and then a layer of fire-retardant paint is applied on the outside of the anti-corrosion paint. The fire-retardant paint is a non-expanding fire-retardant paint. The length of the lower chord 2 is generally based on a 6-meter module and cannot be interrupted in the middle.

[0020] like Figure 4 As shown, the diagonal web member 3 of the Bailey bridge sheet is made of I-shaped hot-rolled steel. The width of the upper and lower flanges of the I-shaped steel is consistent, and the height of the I-shaped steel should be coordinated with the width of the π-shaped groove of the upper chord 1 or the lower chord 2 to facilitate connection. The surface of the I-shaped hot-rolled steel must be ground to remove stains and rust. First, a layer of primer is applied, then a layer of anti-corrosion paint is applied on the outside of the primer, and finally a layer of fire-retardant paint is applied on the outside of the anti-corrosion paint. The fire-retardant paint is a non-expanding fire-retardant paint. The angle between the length of the diagonal web member 3 and the upper chord 1 or the lower chord 2 should not be less than 30°. The end of the diagonal web member 3 extends into the groove of the corresponding upper chord 1 or lower chord 2 and is tightened. Then, the flange of the diagonal web member 3 is connected to the upper chord or lower chord 2 by welding. The other end of the diagonal web member 3 is tightened to the vertical web member 4, and then an octagonal connecting plate 5 or a hexagonal connecting plate 6 is welded to the flange of the diagonal web member 3.

[0021] like Figure 4 The vertical web members 4 of the Bailey bridge steel sheet are made of I-shaped hot-rolled steel (with the same structural form as the diagonal web members 3). The width of the upper and lower flanges of the I-shaped steel is consistent, and the height of the I-shaped steel should be coordinated with the width of the π-shaped groove of the upper chord 1 or the lower chord 2 to facilitate connection. The surface of the I-shaped hot-rolled steel must be ground to remove stains and rust. First, a layer of primer is applied, then a layer of anti-corrosion paint is applied on the outside of the primer, and then a layer of fire-retardant paint is applied on the outside of the anti-corrosion paint. The fire-retardant paint is a non-expanding fire-retardant paint. The length of the vertical web members 4 is determined by calculation. The vertical web members 4 are integral members and cannot be interrupted in the middle. The two ends of the vertical web members 4 are respectively inserted into the grooves of the upper chord 1 and the lower chord 2 and tightened. Then, the flanges of the vertical web members 4 are connected to the upper chord 1 or the lower chord 2 by welding.

[0022] Combination Figure 1 , Figure 5 and Figure 6 As shown, at the intersection of the middle members of the Bailey steel sheet, two octagonal connecting plates 5 are used to clamp them together, and then the flanges of each member are welded to the octagonal connecting plates 5. At the intersection of the members at both ends of the Bailey steel sheet, two hexagonal connecting plates 6 are used to clamp them together, and then the flanges of each member are welded to the hexagonal connecting plates 6.

[0023] In this embodiment, the octagonal connecting plate 5, which serves as the intermediate node connector, is made of hot-rolled steel (Q355B) with a thickness of not less than 8mm; the hexagonal connecting plate 6, which serves as the end node connector, is made of hot-rolled steel (Q355B) with a thickness of not less than 8mm, and its long side is flush with the vertical web member 4.

[0024] Combination Figure 1 and Figure 7 As shown, the upper chord 1 and lower chord 2 of the Bailey steel sheet are respectively provided with longitudinal splicing structures at both ends. Each longitudinal splicing structure includes a female connector 7 located on one side of the chord. The female connector 7 consists of two pieces, made of hot-rolled square steel tubing with pin holes for easy pin-bolt connection. The height of the female connector 7 is consistent with the height of the upper chord 1 and lower chord 2. The width of the female connector 7 on the upper chord 1 should be consistent with the cantilever width of the lower flange of the upper chord 1, and the width of the female connector 7 on the lower chord 2 should be consistent with the cantilever width of the upper flange of the lower chord 2. The female connector 7 is then fixedly connected to the upper chord 1 or lower chord 2 by welding.

[0025] Combination Figure 1 and Figure 8 As shown, the male connector 8 at the other end of the upper chord 1 and lower chord 2 of the Bailey steel sheet is a single piece made of hot-rolled square steel tubing with pin holes for pinning. The height of the male connector 8 is the same as the height of the upper chord 1 or lower chord 2, and the width of the male connector 8 is the same as the width of the groove in the upper chord 1 or lower chord 2. The male connector 8 is then fixedly connected to the upper chord 1 or lower chord 2 by welding.

[0026] In use, insert the male connector 8 into the groove formed between the two female connectors 7, align the pin hole on the male connector 8 with the pin hole on the female connector 7, and then insert a pin into the aligned pin hole to fix it, thereby realizing the longitudinal connection between the Bailey steel sheets.

[0027] In this embodiment, the female connector 7 and the male connector 8 are made of Q355B material.

[0028] like Figure 9As shown, the two ends of the horizontally adjacent Bailey steel sheets are welded together by angle steel transverse bracing 9 and angle steel diagonal bracing 10. At the same time, the upper chord 1 of the Bailey steel sheet is welded to the upper flange of the Bailey steel sheet by strip steel plates 12 with a width of 100mm and a thickness of the same as the upper flange of the upper chord 1 at a longitudinal spacing of 200mm, and assembled into a truss system 11. The truss system 11 is then welded together horizontally by angle steel transverse bracing 9 and angle steel diagonal bracing 10, and finally assembled into a steel truss system.

[0029] like Figure 10 As shown, the stud 14, acting as a shear connector, penetrates the profiled steel sheet bottom mold 13 and is welded to the strip steel sheet 12 and the flange portion of the upper chord 1. The type of reinforced truss floor decking is based on the width requirements for reinforced truss floor decking in the "Reinforced Truss Floor Decking" (JG / T 368-2012) specification.

[0030] In this embodiment, the bottom mold 13 of the profiled steel sheet is made of steel plate or aluminum alloy plate with a thickness of not less than 5mm.

[0031] In use, the steel truss floor deck consists of a profiled steel sheet bottom formwork 13, top chord reinforcement, bottom chord reinforcement, web reinforcement, studs 14, and concrete. The steel truss, composed of the top chord reinforcement, bottom chord reinforcement, and web reinforcement, is connected to the profiled steel sheet bottom formwork 13 by resistance spot welding. The steel truss floor deck rests on the steel truss system. The profiled steel sheet bottom formwork 13 serves as a support for the poured concrete. The poured concrete, together with the steel truss and studs 14, forms the steel truss floor deck.

[0032] In this embodiment, the top chord reinforcement, bottom chord reinforcement, and web reinforcement are made of HRB400 or CRB550 steel with a diameter of not less than 8mm; HRB500 or CRB600H can also be used. The shear studs 14 are made of ML15AI material with a diameter of not less than 19mm. The length of each stud stud is not less than four times its diameter, and the longitudinal and transverse spacing of the shear studs 14 is not less than six times their diameter. They are also staggered with the truss reinforcement. The concrete material is of a strength grade of not less than C30, and the concrete slab thickness is not less than 120mm.

[0033] like Figure 11 As shown, the platform screen door railing 15 is connected to the steel truss floor slab via an embedded part. This embedded part can be any type of embedded part found in existing technology, and it serves to connect the platform screen door railing to the steel truss floor slab.

[0034] like Figure 12 and Figure 13As shown, the bottom lower chords 2 at both ends of the steel truss system are welded to the concrete piers 16. For example, a steel plate is embedded in the top of the concrete bridge deck, and hooked steel bars are installed at the location of the embedded steel plate and anchored to the concrete piers 16. The top of the embedded steel plate is flush with the concrete piers 16, so that the lower chords 2 can be welded and fixed to the embedded steel plate.

[0035] In this embodiment, the embedded part uses Q235B steel with a plate thickness of not less than 8mm, and the transverse length of the plate should be greater than the flange width of the lower chord 2. The hooked steel bar is anchored into the lower concrete pier column, and the anchorage length should meet the specification requirements. The diameter of the hooked steel bar is not less than 8mm, and the number of steel bars is not less than 4. The hooked steel bar is connected to the embedded plate by through-hole plug welding or fillet weld.

[0036] Finally, the permanent platform structure, which is composed of Bailey steel sheets and connected to the steel truss floor slab, is assembled into a whole and fixed to the concrete pier 16.

[0037] In specific implementation, this embodiment includes the following construction methods: 1) The Bailey steel sheets are assembled into a space truss system in advance at the prefabrication plant. At the same time, the profiled steel sheet bottom mold 13 is welded to the upper flange of the upper chord 1 of the steel truss system by studs 14. Then the steel truss is welded to the profiled steel sheet bottom mold 13, and finally concrete is poured to form a prefabricated assembly component.

[0038] 2) Transport each prefabricated assembly section to the construction site and prepare the connecting pins.

[0039] 3) Two truck cranes are set up at both ends of the long span section, and a double-crane lifting construction method is adopted to lift half of the entire prefabricated system respectively.

[0040] 4) First, fix the support position of the precast component, then level it and connect the pins.

[0041] 5) After the splicing is completed, other work such as surface decoration can be carried out.

[0042] Although the above embodiments have described the concept and embodiments of the present invention in detail with reference to the accompanying drawings, those skilled in the art will recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, and therefore will not be elaborated here.

Claims

1. A construction method for a permanent large-span platform structure, characterized in that: The construction method includes the following steps: The steel truss system is assembled in a prefabrication condition. The steel truss system is composed of several Bailey steel sheets, and the horizontally adjacent Bailey steel sheets are connected and fixed to form a whole through a horizontal splicing structure. The bottom mold of the profiled steel sheet is welded onto the steel truss system through shear connectors, and the steel truss is welded onto the bottom mold of the profiled steel sheet. Then, concrete is poured to form a steel truss floor deck. The steel truss floor deck is fixedly connected to the steel truss system to form a prefabricated assembly section of the platform layer structure of the whole structure. The prefabricated assembly section of the platform layer structure is lifted and the support is fixedly installed at the corresponding position below the prefabricated assembly section of the platform layer structure. After leveling the prefabricated assembly section of the platform layer structure, the longitudinally adjacent Bailey steel sheets are connected and fixed to form an integral structure through a longitudinal splicing structure. After assembly, subsequent construction will be carried out on the steel truss floor slab.

2. The construction method for a permanent large-span platform structure according to claim 1, characterized in that: The Bailey steel sheet includes an upper chord and a lower chord. A vertical web member is welded between the upper chord and the lower chord. An oblique web member is welded between the upper chord and the vertical web member and between the lower chord and the vertical web member. A welded joint connector is fixed at the welding joint position between the oblique web member and the vertical web member.

3. The construction method for a permanent large-span platform structure according to claim 2, characterized in that: The node connectors include octagonal connectors and hexagonal connectors. The octagonal connectors are clamped at the intersection of the diagonal web members and vertical web members in the middle of the Bailey steel sheet, and the hexagonal connectors are clamped at the intersection of the diagonal web members and vertical web members at both ends of the Bailey steel sheet.

4. The construction method for a permanent large-span platform structure according to claim 1, characterized in that: A female connector is provided at one end of the Bailey steel sheet, and a male connector is provided at the other end. The female connector has a groove that is adapted to the male connector, and the male connector is snapped into the groove. The female connector and the male connector are provided with pin holes, and the two are fixedly connected by a pin that passes through the pin hole.

5. The construction method for a permanent large-span platform structure according to claim 1, characterized in that: The transverse splicing structure includes transverse angle steel bracing and diagonal angle steel bracing. The transverse angle steel bracing is arranged horizontally, and its two ends are respectively welded to two adjacent transverse Bailey steel sheets. The diagonal angle steel bracing is arranged diagonally, and its two ends are respectively welded to two adjacent transverse Bailey steel sheets.

6. The construction method for a permanent large-span platform structure according to claim 1, characterized in that: A strip steel plate is welded and fixed together on the top surface of several horizontal Bailey steel sheets, and the steel truss floor deck rests on the strip steel plate.

7. The construction method for a permanent large-span platform structure according to claim 1, characterized in that: The shear-resistant connector is a stud. The bottom mold of the profiled steel sheet rests on the strip steel sheet, and the stud penetrates the bottom mold of the profiled steel sheet and is welded to the strip steel sheet and the Bailey steel sheet.

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