Profiled steel sheet laying structure applicable to the scaffold-free construction of steel-concrete composite beam bridges

Abstract

The present invention relates to a profiled steel sheet laying structure applicable to the bracketless construction of steel-concrete composite beam bridges, including a laying structure for the compression zone of the steel main beam, a laying structure for the tension zone of the steel main beam, and a laying structure for the cantilever flange. The laying structure for the compression zone of the steel main beam, the laying structure for the tension zone of the steel main beam, and the laying structure for the cantilever flange all include a reinforced concrete bridge deck and a steel main beam. Support mechanisms are provided on both side surfaces of the steel main beam in the laying structure for the compression zone of the steel main beam, on both side surfaces of the steel main beam in the laying structure for the tension zone of the steel main beam, and on the cantilever side of the steel main beam in the laying structure for the cantilever flange. Profiled steel sheets are provided on the support mechanisms, and the reinforced concrete bridge deck is arranged on the upper surface of the profiled steel sheets. The profiled steel sheets have a thin thickness and serve as the support formwork for the concrete bridge deck to save steel consumption; the support mechanisms are connected to the steel main beam through at least two welds to avoid fatigue cracking of the steel main beam caused by single or concentrated welds, thereby ensuring the service life and strength of the steel main beam.

Description

Technical Field

[0001] The present invention relates to the field of steel-concrete composite bridges, and in particular to a profiled steel sheet laying structure suitable for the scaffold-free construction of steel-concrete composite beam bridges. Background Art

[0002] Steel-concrete composite beam bridges have the advantages of saving steel consumption, light hoisting weight, convenient processing, good durability, etc., and are commonly used structural forms for the industrialized construction of medium-span structural bridges. In a steel-concrete composite beam bridge, the combination of a steel box girder or a steel plate girder and a concrete bridge deck is the key to the combined structural force. The concrete bridge deck not only participates in the structural force but also directly bears the wheel load. Its construction methods include precast and cast-in-situ.

[0003] The cast-in-situ bridge deck has good integrity, the bridge deck is closely combined with the top plate (upper flange) of the steel girder, and the shear connectors are convenient to construct. It is a commonly used bridge deck construction method for steel-concrete composite beam bridges. The cast-in-situ concrete bridge deck is divided into two types: scaffold cast-in-situ and scaffold-free cast-in-situ. The traditional scaffold cast-in-situ bridge deck requires the erection of a bottom formwork, which is cumbersome, has a high risk of high-altitude operation, and a high manufacturing cost; the scaffold-free construction, which cancels the bottom formwork for bridge deck pouring, speeds up the construction progress, and is a bridge deck construction method that should be vigorously promoted under the background of industrialization.

[0004] At present, there are steel-concrete composite bridge deck construction methods, steel bottom plate bridge deck construction methods, etc. for the scaffold-free construction of the bridge deck. However, whether it is the steel bottom plate of the composite bridge deck or the steel bottom formwork used as a formwork, the thickness of its steel plate is between 6 and 10 mm, and the steel consumption is huge. The increase in the unit steel consumption makes the composite structure bridge not have a cost advantage and is not conducive to popularization and use.

[0005] The profiled steel sheet has the characteristics of light self-weight, low steel consumption (the thickness of the profiled steel sheet used in building roofs is only 0.8 - 1.2 mm), and high finished product rate, and is currently applied in the concrete pouring of building roofs. In traditional building construction, the profiled steel sheet is placed on the top surface of the ring beam. For a steel-concrete composite beam bridge, due to the influence of the height of the profiled steel sheet (generally about 6 cm wave height), using the method of placing the profiled steel sheet in building construction will reduce the effective thickness of the concrete bridge deck. Therefore, a more reasonable layout method of the profiled steel sheet should be to lower the profiled steel sheet below the top surface of the upper flange of the steel girder to ensure the effective thickness of the concrete bridge deck. However, placing the profiled steel sheet below requires welding support connection accessories on the flange of the steel girder, and the welding of the support connection accessories will cause fatigue cracking problems in the flange of the main steel girder. One of the significant differences between a steel structure bridge and a concrete structure lies in the fatigue characteristics of steel structure components. Therefore, how to fix the profiled steel sheet as the formwork for the cast-in-situ concrete bridge deck during scaffold-free construction without causing fatigue cracking is the problem that the present invention focuses on and needs to solve.

[0006] In existing steel-concrete composite bridges with application numbers 202010373302.9, 201811570095.5, 200410051061.7, 202110027335.2, 201710640860.5, etc., profiled steel sheets are used to support the concrete bridge deck. However, the profiled steel sheets are directly laid on the upper surface of the main girder, similar to the laying method used in traditional building construction. Due to the influence of the height of the profiled steel sheet (generally with a wave height of about 6 cm), there are still problems such as a relatively low effective thickness of the concrete bridge deck. In addition, since the stress conditions of the main girders at different positions of the beam bridge are different, the same laying method is used in all positions in the existing technology, and a more reasonable support structure is not designed according to the stress conditions of the main girders. The profiled steel sheets in some areas reach the fatigue limit first, and the profiled steel sheets in some areas reach the fatigue limit later, resulting in uneven service lives of each part. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges. The profiled steel sheet is used as the support formwork for the concrete bridge deck to save steel consumption, ensure the effective thickness of the concrete bridge deck, and in addition, prevent fatigue cracking of the steel main girder, thereby ensuring the strength of the steel main girder.

[0008] The technical solution adopted by the present invention to solve its technical problems is: a profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges, including a laying structure for the compression zone of the steel main girder, a laying structure for the tension zone of the steel main girder, and a laying structure for the cantilever flange. The laying structure for the compression zone of the steel main girder, the laying structure for the tension zone of the steel main girder, and the laying structure for the cantilever flange all include a reinforced concrete bridge deck and a steel main girder with a cross-section in the shape of an I-beam composed of an upper flange, a lower flange, and a web. Support mechanisms are arranged on both side surfaces of the steel main girder in the laying structure for the compression zone of the steel main girder, both side surfaces of the steel main girder in the laying structure for the tension zone of the steel main girder, and the cantilever side of the steel main girder in the laying structure for the cantilever flange. The support mechanism is connected to the steel main girder through at least two welds. A profiled steel sheet is arranged on the support mechanism. The highest point on the upper surface of the profiled steel sheet is at the same height as the upper surface of the upper flange, or the highest point on the upper surface of the profiled steel sheet is lower than the upper surface of the upper flange. The reinforced concrete bridge deck is arranged on the upper surface of the profiled steel sheet.

[0009] Preferably, the support mechanism in the laying structure for the compression zone of the steel main girder is an angle steel with a cross-section in the shape of an L composed of a horizontal toe and a vertical toe. The vertical toe is welded to both the upper surface and the lower surface of the upper flange at the same time. The two ends of the profiled steel sheet are located on the horizontal toes of the angle steels of adjacent steel main girders.

[0010] Furthermore, the leg size of the weld is 4 to 6 mm.

[0011] Furthermore, the length of the profiled steel sheet located on the transverse toe is greater than or equal to 50 mm.

[0012] Preferably, the supporting mechanism of the laying structure in the tension zone of the steel main beam includes a J-shaped hook plate and a T-shaped angle steel. A horizontal connecting plate is arranged at the top of the J-shaped hook plate. The two side edges of the connecting plate are welded to the lower surface of the upper flange. The lower part of the vertical right toe of the T-shaped angle steel is inserted into the J-shaped hook plate, and the upper end of the vertical right toe of the T-shaped angle steel extends above the upper flange. A tension bar is arranged on the upper surface of the upper flange, and the two ends of the tension bar are welded to the vertical right toes of the T-shaped angle steels on both sides of the upper flange. The end of the profiled steel sheet is located on the horizontal right toe of the T-shaped angle steel.

[0013] Furthermore, the distance from the weld between the connecting plate and the upper flange to the edge of the upper flange is greater than or equal to 15 mm.

[0014] Furthermore, the hook depth of the J-shaped hook plate is greater than or equal to 30 mm.

[0015] Preferably, the supporting mechanism of the laying structure of the cantilever flange includes multiple cantilever beams with an I-shaped cross-section. The top plate of the cantilever beam is welded to the upper flange, and the middle vertical plate and the bottom plate of the cantilever beam are welded to the web of the steel main beam. An external hanging plate with an L-shaped cross-section is arranged on the upper surface of the end of the cantilever beam far from the steel main beam. The two ends of the profiled steel sheet are located on adjacent cantilever beams, and the side of the profiled steel sheet far from the steel main beam is located on the external hanging plate.

[0016] Furthermore, an end plate is arranged on the side of the profiled steel sheet close to the steel main beam. The end plate is attached to the side surface of the upper flange of the steel main beam, and a plurality of through holes (elliptical holes) evenly distributed in the length direction are arranged on the end plate. The bottom reinforcement bars of the bridge deck penetrate through the through holes to form an open-hole plate structure.

[0017] Furthermore, multiple rows of shear studs are arranged on the cantilever beam. The upper ends of the shear studs penetrate through the profiled steel sheet and are buried into the reinforced concrete bridge deck as connecting pieces.

[0018] The beneficial effects of the present invention are as follows: 1. The thickness of the profiled steel sheet is thin. Using the profiled steel sheet as the support formwork for the concrete bridge deck can save steel consumption. For the steel-concrete composite beam bridge with a pier height within 15 m, the cost of cast-in-place concrete bridge deck support is about 230 yuan per square meter, the formwork cost using a 6-mm steel bottom plate as the bottom formwork is about 420 yuan per square meter, while the formwork cost using a 1.2-mm galvanized profiled steel sheet as the bottom formwork for scaffold-free construction is about 55 yuan per square meter. In terms of cost comparison, the scaffold-free bridge deck construction plan with profiled steel sheets has an obvious cost advantage. 2. The supporting mechanism is connected to the steel main beam through at least two welds, avoiding fatigue cracking of the steel main beam caused by single or concentrated welds, thus ensuring the service life and strength of the steel main beam. 3. Since the highest point on the upper surface of the profiled steel sheet is at the same height as the upper surface of the upper flange, or the highest point on the upper surface of the profiled steel sheet is lower than the upper surface of the upper flange, the effective thickness of the reinforced concrete bridge deck is ensured without increasing the elevation of the upper surface of the reinforced concrete bridge deck, enabling the bridge deck to meet the load-bearing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of Embodiment 1;

[0020] Figure 2 is an enlarged schematic diagram of part A in Embodiment 1;

[0021] Figure 3 is a schematic diagram of Embodiment 2;

[0022] Figure 4 is an enlarged schematic diagram of part B in Embodiment 2;

[0023] Figure 5 is a schematic diagram of Embodiment 3;

[0024] Figure 6 is an enlarged schematic diagram of part C in Embodiment 3;

[0025] REFERENCE SIGNS: 1 - upper flange; 2 - lower flange; 3 - weld; 4 - profiled steel sheet; 5 - angle steel; 6 - J-shaped hook plate; 7 - reinforced concrete bridge deck; 8 - T-shaped angle steel; 9 - connecting plate; 10 - tie rod; 11 - cantilever beam; 12 - external hanging plate; 13 - end plate; 14 - through hole; 15 - shear stud. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present invention will be further described below with reference to the drawings and embodiments.

[0027] The steel-concrete composite bridge is divided into multiple regions, specifically including the compression zone of the steel main girder, the tension zone of the steel main girder, and the cantilever flange. Profiled steel sheets 4, reinforced concrete bridge decks 7, and steel main girders with an I-shaped cross-section composed of upper flanges 1, lower flanges 2, and webs are provided in multiple regions. The profiled steel sheets 4 are supported by a support mechanism. Due to different forces, different support mechanisms need to be used when laying the profiled steel sheets 4 in different regions. Specifically:

[0028] Example 1

[0029] As Figure 1 、 Figure 2 shown, the profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges in this embodiment includes a reinforced concrete bridge deck 7 and a steel main girder with an I-shaped cross-section composed of an upper flange 1, a lower flange 2, and a web. A support mechanism is provided on the side of the steel main girder. The support mechanism is an angle steel 5 with an L-shaped cross-section composed of a horizontal toe and a vertical toe. The vertical toe is welded to both the upper surface and the lower surface of the upper flange 1 at the same time. The two ends of the profiled steel sheet 4 are located on the horizontal toes of the angle steels 5 of adjacent steel main girders. The highest point on the upper surface of the profiled steel sheet 4 is at the same height as the upper surface of the upper flange 1, or the highest point on the upper surface of the profiled steel sheet 4 is lower than the upper surface of the upper flange 1. The reinforced concrete bridge deck 7 is arranged on the upper surface of the profiled steel sheet 4.

[0030] This embodiment is applicable to the compression zone of the steel main girder. The upper flange 1 bears compressive stress under the dead load, and the stress amplitude under the live load is not very significant for the fatigue effect. Therefore, directly welding the angle steel 5 to the upper surface and the lower surface of the upper flange 1 can meet the requirements. There are two welds 3, one is located on the upper surface of the upper flange 1, and the other is located on the lower surface of the upper flange 1. And the weld 3 is a fillet weld, and the leg size of the weld 3 is 4 to 6 mm to ensure the strength of the welded connection.

[0031] The profiled steel sheet 4 adopts an open-type profiled steel sheet. Before laying, plug plates are welded to both ends of the profiled steel sheet 4 first to prevent the mortar from flowing out from both ends of the profiled steel sheet 4 when pouring concrete. The length of the part of the profiled steel sheet 4 located on the horizontal toe is greater than or equal to 50 mm, ensuring that there is a large enough support length between the horizontal toe and the profiled steel sheet 4, and improving the stability and support capacity of the profiled steel sheet 4.

[0032] The construction process of this embodiment is as follows: First, weld the angle steels 5 on both sides of the upper flange 1 of the steel main girder. The horizontal toes of the angle steels 5 are located at the bottom of the vertical toes, and double-sided fillet welds are used, that is, the vertical toes are welded to both the upper surface and the lower surface of the upper flange 1 at the same time, which can reduce the weld toe failure caused by torsion of the single-sided weld. Then, weld the plug plates to both ends of the profiled steel sheet 4 to block the notches on the upper surface of the profiled steel sheet 4. Next, lay the profiled steel sheet 4 on the horizontal toes of adjacent steel main girders, then tie the steel bars, and finally pour the concrete to obtain the reinforced concrete bridge deck 7.

[0033] Embodiment 2

[0034] As Figure 3 and Figure 4 shown, the profiled steel sheet laying structure applicable to the scaffold-free construction of a steel-concrete composite beam bridge in this embodiment includes a reinforced concrete bridge deck 7 and a steel main beam with an I-shaped cross-section composed of an upper flange 1, a lower flange 2, and a web. A supporting mechanism is provided on the side of the steel main beam. The supporting mechanism includes a J-shaped hook plate 6 and a T-shaped angle steel 8. A horizontal connecting plate 9 is provided at the top of the J-shaped hook plate 6. The two side edges of the connecting plate 9 are welded to the lower surface of the upper flange 1. The lower part of the vertical angle toe of the T-shaped angle steel 8 is inserted into the J-shaped hook plate 6, and the upper end of the vertical angle toe of the T-shaped angle steel 8 extends above the upper flange 1. A tension rod 10 is provided on the upper surface of the upper flange 1. The tension rod 10 can be made of a steel strip or the like. The two ends of the tension rod 10 are welded to the vertical angle toes of the T-shaped angle steels 8 on both sides of the upper flange 1. The end of the profiled steel sheet 4 is located on the horizontal angle toe of the T-shaped angle steel 8. The highest point on the upper surface of the profiled steel sheet 4 is at the same height as the upper surface of the upper flange 1, or the highest point on the upper surface of the profiled steel sheet 4 is lower than the upper surface of the upper flange 1. The reinforced concrete bridge deck 7 is arranged on the upper surface of the profiled steel sheet 4.

[0035] The connecting plate 9 and the J-shaped hook plate 6 are integrally formed. The hook depth of the J-shaped hook plate 6 is greater than or equal to 30 mm. The weld 3 between the two side edges of the connecting plate 9 and the upper flange 1 is a fillet weld, and the distance from the weld 3 to the edge of the nearest upper flange 1 is greater than or equal to 15 mm. The length of the profiled steel sheet 4 located on the horizontal angle toe of the T-shaped angle steel 8 is not less than 50 mm to ensure the strength and supporting capacity of the entire steel structure and reduce the risk of fatigue cracking.

[0036] This embodiment is applicable to the tension zone of the steel main beam, that is, the negative moment zone of the continuous beam. The upper flange 1 of it bears tensile stress under the dead load, and the stress amplitude under the live load has a significant impact on the fatigue effect. The connection between the supporting mechanism and the steel main beam adopts multi-point connection to reduce the stress at the welding joint. Specifically, the horizontal angle toe of the T-shaped angle steel 8 is used to support the profiled steel sheet 4. The gravity of the profiled steel sheet 4 and the reinforced concrete bridge deck 7 and the load when the vehicle passes are transmitted to the vertical angle toe of the T-shaped angle steel 8. The vertical angle toe of the T-shaped angle steel 8 transmits part of the load to the tension rod 10, and the tension rod 10 bears this part of the load. The vertical angle toe of the T-shaped angle steel 8 transmits another part of the load to the J-shaped hook plate 6. Since the load is dispersed, the load borne by the J-shaped hook plate 6 is smaller, thereby reducing the stress at the welding joint between the connecting plate 9 and the upper flange 1 and preventing fatigue cracking of the upper flange 1 at the welding joint.

[0037] The construction process of this embodiment is as follows: First, J-shaped hook plates 6 are welded on both sides of the steel main girder. The connecting plate 9 of the J-shaped hook plate 6 is welded to the lower surface of the upper flange 1. There are 2 weld seams 3, and the leg size is 4 - 6 mm. Then, the vertical angle toes of the T-shaped angle steel 8 are inserted into the J-shaped hook plate 6 to ensure that the bottom of the vertical angle toes of the T-shaped angle steel 8 contacts the bottom of the J-shaped hook plate 6. Then, the tie rod 10 is placed on the upper surface of the upper flange 1, and the tie rod 10 is welded to the T-shaped angle steels 8 on both sides of the upper flange 1. The profiled steel sheet 4 uses an open-type profiled steel sheet. First, plug plates are welded at both ends of the profiled steel sheet 4 to block the notches on the upper surface of the profiled steel sheet 4. Then, the profiled steel sheet 4 is laid on the horizontal angle toes of the T-shaped angle steels 8 of adjacent two steel main girders. The length of the profiled steel sheet 4 located on the horizontal angle toes of the T-shaped angle steel 8 is not less than 50 mm. Finally, steel bars can be tied and concrete can be poured to obtain the reinforced concrete bridge deck 7.

[0038] Embodiment III

[0039] As Figure 5 and Figure 6 shown, the profiled steel sheet laying structure applicable to the non-shoring construction of the steel-concrete composite beam bridge in this embodiment includes a reinforced concrete bridge deck 7 and a steel main girder with an I-shaped cross-section composed of an upper flange 1, a lower flange 2, and a web. A support mechanism is arranged on the side of the steel main girder. The support mechanism includes multiple cantilever beams 11 with an I-shaped cross-section. The top plate of the cantilever beam 11 is welded and connected to the upper flange 1, and the middle vertical plate and the bottom plate of the cantilever beam 11 are welded and connected to the web of the steel main girder. An external hanging plate 12 with an L-shaped cross-section is arranged on the upper surface of the end of the cantilever beam 11 far from the steel main girder. Both ends of the profiled steel sheet 4 are located on adjacent two cantilever beams 11, and the side of the profiled steel sheet 4 far from the steel main girder is located on the external hanging plate 12. The highest point on the upper surface of the profiled steel sheet 4 is at the same height as the upper surface of the upper flange 1, or the highest point on the upper surface of the profiled steel sheet 4 is lower than the upper surface of the upper flange 1. The reinforced concrete bridge deck 7 is arranged on the upper surface of the profiled steel sheet 4.

[0040] This embodiment is applicable to cantilever flanges. In order to ensure the stable support for the profiled steel sheet 4 and the reinforced concrete bridge deck 7, the cantilever beam 11 is welded on the side of the steel main girder. Since the top plate of the cantilever beam 11 is welded and connected to the upper flange 1, and the middle vertical plate and the bottom plate of the cantilever beam 11 are welded and connected to the web of the steel main girder, there are a total of 3 weld seams 3, which disperses the stress and can prevent fatigue cracking at the welded joints. And by arranging the external hanging plate 12 at the end of the cantilever beam 11 far from the steel main girder, the profiled steel sheet 4 can be positioned to prevent the profiled steel sheet 4 from sliding after being laid.

[0041] The profiled steel sheet 4 adopts a closed profiled steel sheet. An end plate 13 is arranged on the side of the profiled steel sheet 4 close to the steel main girder. The end plate 13 can be obtained by straightening the part of the profiled steel sheet 4 close to the upper flange 1. The end plate 13 is attached to the side surface of the upper flange 1 of the steel main girder, and a plurality of oval through holes 14 evenly distributed in the length direction are arranged on the end plate 13. The diameter of the through holes 14 is 50x30mm, and the distance between two adjacent through holes 14 is about 100mm, which is the same as the spacing of the transverse steel bars of the bridge deck. When binding the steel bars, the end of the bottom layer transverse stress-bearing steel bar of the bridge deck penetrates through the through holes 14.

[0042] In order to improve the stability of the profiled steel sheet 4, multiple rows of shear studs 15 are arranged on the cantilever beam 11. The upper end of the shear stud 15 penetrates through the profiled steel sheet 4 and is anchored inside the reinforced concrete bridge deck 7 as a connecting piece. Specifically, the shear studs 15 can be in 3 rows, and are welded and connected to the profiled steel sheet 4 and the cantilever beam 11, connecting the cantilever beam 11, the profiled steel sheet 4 and the reinforced concrete bridge deck 7 into a whole.

[0043] The construction process of this embodiment is as follows: The cantilever beam 11 is welded to the side of the steel main girder. The top plate of the cantilever beam 11 is welded and connected to the upper flange 1, and the middle vertical plate and the bottom plate of the cantilever beam 11 are welded and connected to the web of the steel main girder. The weld seam is a fillet weld, and the size of the weld leg is 4 - 6mm. Then, the hanging plate 12 is welded on the upper surface of the end of the cantilever beam 11 far from the steel main girder. Next, one side of the high profiled steel sheet 4 is cold-bent and straightened to form the end plate 13, and through holes 14 are opened on the end plate 13. Then, the profiled steel sheet 4 is laid. The two ends of the profiled steel sheet 4 are located on two adjacent cantilever beams 11, and the end plate 13 is attached to the side surface of the upper flange 1. The side of the profiled steel sheet 4 far from the upper flange 1 is located on the hanging plate 12. After the profiled steel sheet 4 is laid, the shear studs 15 are welded to penetrate the profiled steel sheet 4, and the profiled steel sheet 4 is welded through, so that the shear studs 15 pass through the profiled steel sheet 4 and are welded and connected to the cantilever beam 11. Finally, the steel bars are bound, the ends of the bottom layer transverse stress-bearing steel bars penetrate through the through holes 14, and the concrete is poured.

[0044] In summary, the scaffold-free construction method of the bridge deck of the steel-concrete composite beam bridge is an objective need for industrialized bridge construction. The scaffold-free construction steel-concrete composite bridge and the profiled steel sheet laying structure for scaffold-free construction of the bridge deck proposed by the present invention include three types: the profiled steel sheet laying structure in the compression zone of the steel main girder, the profiled steel sheet laying structure in the tension zone of the steel main girder, and the profiled steel sheet laying structure of the cantilever flange, covering all working conditions of the profiled steel sheet 4 laying in the scaffold-free construction. The support mechanism is reasonably designed according to the stress conditions of each area. The support mechanism in the area with larger load and affecting the connection strength has higher strength, and the support mechanism in the area with smaller load has a simple structure, ensuring the construction convenience while making the service life of the support mechanism and the profiled steel sheet 4 in each area balanced. This method combines the structural requirements of the fatigue stress of the steel main girder and meets the stress requirements under the construction load. The construction is simple, safe, and saves the construction period.

[0045] For a steel-concrete composite beam bridge with a pier height within 15 m, the cost of cast-in-place concrete bridge deck support is approximately 230 yuan per square meter, the formwork cost using a 6-mm steel bottom plate as the bottom formwork is approximately 420 yuan per square meter, while the cost of using a 1.2-mm galvanized profiled steel sheet as the bottom formwork for scaffold-free construction is approximately 55 yuan per square meter. Comparing from the cost aspect, the construction plan of the profiled steel sheet scaffold-free bridge deck has an obvious cost advantage.

[0046] Meanwhile, the method of constructing the bridge deck with supports has disadvantages such as a relatively long construction period, being not suitable for the casting of the bridge deck of high piers in mountainous areas, and relatively high risks. For the construction method with a steel bottom plate as the bottom formwork, the bottom formwork can be processed in the factory, but the cost is the highest and it is uneconomical. The construction method using the profiled steel sheet 4 as the bottom formwork not only has a relatively low cost, but also solves the problem of concrete casting at the cantilever end of the composite bridge deck; moreover, the galvanized profiled steel sheet 4 has advantages in durability and aesthetics that are difficult to match by other methods. Galvanizing can prevent rust; the use of the profiled steel sheet 4 isolates the contact between air, water and the concrete bridge deck, prolonging the durability and service life of the concrete bridge deck; meanwhile, the surface is smooth and beautiful.

[0047] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. The profiled steel sheet laying structure applicable to the bracketless construction of steel-concrete composite beam bridges includes the laying structure in the compression zone of the steel main beam, the laying structure in the tension zone of the steel main beam, and the laying structure of the cantilever flange. The laying structure in the compression zone of the steel main beam, the laying structure in the tension zone of the steel main beam, and the laying structure of the cantilever flange all include a reinforced concrete bridge deck (7) and a steel main beam with an I-shaped cross-section composed of an upper flange (1), a lower flange (2), and a web. It is characterized in that: Support mechanisms are provided on both side surfaces of the steel main beam in the laying structure of the compression zone of the steel main beam, both side surfaces of the steel main beam in the laying structure of the tension zone of the steel main beam, and the cantilever side of the steel main beam in the laying structure of the cantilever flange. The support mechanism is connected to the steel main beam through at least two welds (3). A profiled steel sheet (4) is provided on the support mechanism. The highest point on the upper surface of the profiled steel sheet (4) is at the same height as the upper surface of the upper flange (1), or the highest point on the upper surface of the profiled steel sheet (4) is lower than the upper surface of the upper flange (1). The reinforced concrete bridge deck (7) is arranged on the upper surface of the profiled steel sheet (4); The support mechanism of the laying structure in the tension zone of the steel main beam includes a J-shaped hook plate (6) and a T-shaped angle steel (8). A horizontal connecting plate (9) is provided at the top of the J-shaped hook plate (6). The two side edges of the connecting plate (9) are welded to the lower surface of the upper flange (1). The lower part of the vertical angle toe of the T-shaped angle steel (8) is inserted into the J-shaped hook plate (6), and the upper end of the vertical angle toe of the T-shaped angle steel (8) extends above the upper flange (1). There is a tie rod (10) on the upper surface of the upper flange (1). The two ends of the tie rod (10) are welded to the vertical angle toes of the T-shaped angle steels (8) on both sides of the upper flange (1). The end of the profiled steel sheet (4) is located on the horizontal angle toe of the T-shaped angle steel (8).

2. The profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges as described in claim 1, characterized in that: The support mechanism of the laying structure in the compression zone of the steel main beam is an angle steel (5) with an L-shaped cross-section composed of a horizontal toe and a vertical toe. The vertical toe is simultaneously welded to the upper surface and the lower surface of the upper flange (1). The two ends of the profiled steel sheet (4) are located on the horizontal toes of the angle steels (5) of adjacent steel main beams.

3. The profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges as described in claim 2, characterized in that: The leg size of the weld (3) is 4 to 6 mm.

4. The profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges as described in claim 2, characterized in that: The length of the part of the profiled steel sheet (4) located on the horizontal toe is greater than or equal to 50 mm.

5. The profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges according to claim 1, characterized in that: The distance from the weld (3) between the connecting plate (9) and the upper flange (1) to the edge of the upper flange (1) is greater than or equal to 15 mm.

6. The profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges as described in claim 1 is characterized in that: The hook depth of the J-shaped hook plate (6) is greater than or equal to 30 mm.

7. The profiled steel sheet laying structure applicable to the non-shoring construction of steel-concrete composite beam bridges according to claim 1, characterized in that: The support mechanism of the laying structure of the cantilever flange includes a plurality of cantilever beams (11) with an I-shaped cross-section. The top plate of the cantilever beam (11) is welded to the upper flange (1), and the middle vertical plate and the bottom plate of the cantilever beam (11) are welded to the web of the steel main beam. An external hanging plate (12) with an L-shaped cross-section is provided on the upper surface of the end of the cantilever beam (11) far from the steel main beam. The two ends of the profiled steel sheet (4) are located on adjacent cantilever beams (11), and the side of the profiled steel sheet (4) far from the steel main beam is located on the external hanging plate (12).

8. The profiled steel sheet laying structure applicable to the bracketless construction of steel-concrete composite beam bridges according to claim 7, characterized in that: An end plate (13) is arranged on the side of the profiled steel sheet (4) close to the steel main beam. The end plate (13) is attached to the side surface of the upper flange (1) of the steel main beam, and a plurality of through holes (14) evenly distributed in the length direction are arranged on the end plate (13).

9. The profiled steel sheet laying structure applicable to the scaffold-free construction of steel-concrete composite beam bridges according to claim 7, characterized in that: Multiple rows of shear studs (15) are arranged on the cantilever beam (11). The upper ends of the shear studs (15) penetrate through the profiled steel sheet (4) and are cast and buried inside the reinforced concrete bridge deck (7).

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