A far-angle connecting bridge deck structure

Abstract

The present application discloses a far-angle connection bridge deck structure, which solves the problem of fatigue cracking of the welds connecting the longitudinal ribs and the top plate of the traditional orthogonal anisotropic bridge deck structure. The key points of the technical solution are a far-angle connection longitudinal rib, which includes at least one web and a flange, the flange is located at the end of the web, the longitudinal rib is formed by bending or rolling a flat steel plate, the flange and the web have a rotation angle α, 90°≤α≤135°, the flange has a plurality of connection holes, the intersection point of the center line of the web thickness and the plane where the top surface of the flange is located is C, the shortest distance from point C to the connection hole is d1, the web plate thickness is t, t≤d1≤5t. The longitudinal rib is connected to the top plate through the connector on the flange, so that the connection position is far away from the rotation fulcrum of the longitudinal rib web, that is, the stress sensitive area, which significantly reduces the probability of fatigue cracking at the connection between the top plate and the longitudinal rib.

Description

Technical Field

[0001] The present application relates to the field of bridge engineering, and in particular to a bridge deck structure. Background Art

[0002] The orthotropic steel bridge deck structure in the bridge industry is a non-single-layer structure with a stiffened steel plate structure that uses various stiffening structural measures to strengthen the structure on the back of the top plate that bears external loads. The plate-shaped stiffeners are used to strengthen the rigidity of the components and ensure local stability. The traditional orthotropic bridge deck structure includes a top plate and stiffening ribs. The stiffening ribs include longitudinal ribs and transverse ribs. The top plate, longitudinal ribs and transverse ribs form an organic whole that is synergistically stressed, and the plates are mainly connected by welding.

[0003] Under the same load, the stress of orthotropic steel bridge deck structure is much lower than that of single steel plate, and it has a larger section inertia moment than single steel plate, which means it has greater stiffness than single steel plate. However, it also has many disadvantages. A large number of cracks and fatigue phenomena have occurred in orthotropic bridge decks all over the world, and this is the main cause of various common problems such as rutting, longitudinal and transverse cracks in the bridge deck pavement layer. Common problems have become a world-class stubborn problem in its application for nearly 70 years, and no perfect solution has been found for many years.

[0004] Numerous studies on orthotropic steel bridge deck structures have shown that the main factors causing common fatigue problems are: longitudinal ribs, especially the structural form of longitudinal ribs, and the welding or connection structures between components.

[0005] First, the existing longitudinal rib side walls are arranged on the back of the top plate at an intersection vertically or obliquely with the top plate. The top plate directly bears the wheel load, and the longitudinal rib web is fixedly connected to the top plate by welding. This structural form results in that the longitudinal rib web and the top plate can only be connected by a T-joint butt weld, and many high-end welding methods are difficult to apply. The existing commonly used welding methods are mostly about 75% partial penetration welding, with a shallow penetration depth, a total weld depth of about 8 mm, a small weld cross-section, and large welding consumables, auxiliary materials, and heat input.

[0006] like Figure 1 As shown, the existing weld is located at the intersection of the web of the longitudinal rib 200 and the top plate 100. The weld is located in a sensitive area of ​​stress concentration. When an external load acts on the top plate, whether it acts on the top plate between adjacent longitudinal ribs or on the top plate inside the closed longitudinal rib, the top plate will roll with the intersection as the fulcrum. In traditional practices, since the weld is located at the fulcrum, the distance from the weld root or weld toe to the fulcrum is small, the force arm is short, and the tensile force borne by the weld root or weld toe is large. Under the repeated action of external loads, the weld is very likely to initiate fatigue cracks from the weld heel and weld toe to the top plate and the web of the longitudinal rib. However, it is difficult to increase the cross-section of the weld bead in the existing butt joint structure of the longitudinal rib and the top plate, and the weld strength is insufficient.

[0007] Although double-sided welding and upsetting of the upper edge of the longitudinal rib web have been developed in recent years, these methods are all aimed at increasing the cross-sectional area of ​​the weld bead at that location, thereby improving the weld strength at that location, in order to solve the problem of fatigue cracking at the connection between the longitudinal rib and the top plate. For example, patent CN201210467772.7 discloses a hot-rolled U-shaped reinforcing rib for bridges, which uses rectangular steel blanks and is rolled into a U-rib with a variable cross-section through multiple hot rolling processes. The top of the U-rib is upset to form a folded edge to improve the problem of small contact area between the longitudinal rib and the bridge and stress concentration. In reality, U-ribs are often customized products with small usage. This patent is similar to the hot rolling forming process. Although it can theoretically produce longitudinal rib structures of various cross-sections, it is necessary to add the hot rolling process of the steel plant from the source of the raw materials, which requires large equipment investment and high cost, and is not suitable for actual production. Summary of the invention

[0008] The invention purpose of this application is to solve the problem of fatigue cracking of the welds connecting the longitudinal ribs and the top plate of the traditional orthotropic bridge deck structure, and to provide a bridge deck structure with a far-angle connection. The longitudinal ribs are connected to the top plate by flanges, so that the connection position is far away from the rotation fulcrum of the longitudinal rib web, that is, the stress-sensitive area, which significantly reduces the probability of fatigue cracking at the connection between the top plate and the longitudinal ribs.

[0009] In order to achieve the above invention objectives, this application adopts the following technical solutions:

[0010] The present application provides a far-angle connection bridge deck structure, including a top plate and a far-angle connection longitudinal rib, including at least one web and a flange, the flange is located at the end of the web, the longitudinal rib is formed by bending or rolling a flat steel plate, the flange and the web have a rotation angle α, 90°≤α≤135°; the flange has multiple connection holes, the intersection of the center line of the web thickness and the plane where the top surface of the flange is located is C, the shortest distance from point C to the connection hole is d1, the web thickness is t, t≤d1≤5t; the point C is inside the top surface of the flange, the connecting member is a friction welding disc, and the friction welding disc fixes the longitudinal rib and the top plate by rotating friction welding. The friction welding disc connection is particularly suitable for steel bridge deck structures. Since the top plate of the steel bridge deck structure is a direct structural force-bearing member, opening a hole in the top plate will weaken the rigidity of the top plate, and high-strength welding can be achieved without opening a hole in the top plate. Secondly, multiple longitudinally spaced welding pads form independent welding islands, which avoid the shortcomings of poor fatigue resistance and easy extension and development of cracks in traditional corner welds. The island chain structure is formed between the welding islands through the workpiece's own stiffness, which is not only conducive to the formation of the overall structure, but also utilizes the strain of the parent material between the welding islands to isolate the probability of crack development between the welding islands. Through the intermediate welding pad, only a very small amount of energy needs to be input to rotate it to achieve the purpose of welding two large workpieces, especially long, large, and heavy workpieces, as well as non-circular workpieces, which significantly expands the application scope of friction welding and makes it a reality to apply this high-end welding process to common metal components such as bridges. Compared with traditional fusion welding, friction welding is solid-state welding. Impurity pores are broken and squeezed out during welding. The initial defect of the weld is one of the main factors of fatigue cracking. Friction welding has high welding strength and good fatigue resistance, which can effectively improve the fatigue resistance of steel bridge decks.

[0011] Preferably, the end surface of the friction welding disc close to the top plate is an inner concave surface. Because the outer line speed is larger, the input energy is large, and the melting is fast, while the center line speed is 0, the input energy is small, and the melting is slow, the pure circular plane of traditional friction welding cannot achieve the effect of deep embedding into the parent material, or the center area limits its deep embedding efficiency.

[0012] The end face of the pad in the embodiment of the present application adopts an inner concave surface that tilts inward along the edge toward the center of the circle. During welding, the edge of the end face becomes the first part to contact the second workpiece. The metal in this area melts first at high temperature, so that the linear speed, energy input, and melting speed of the outer side with the greatest force are further prioritized; at the same time, the inner concave surface with a certain slope deepens the depth of the outer welding interface embedded in the top plate parent material, increases the bonding strength, and improves the shear resistance of the welded joint. Secondly, the funnel-shaped concave surface helps the molten metal flow to the middle and squeeze out through the cavity.

[0013] Preferably, the friction pad is embedded in the top plate, and the distance between the friction pad and the top plate is d2, d2 ≥ 2mm. Compared with other connection methods or other welding methods, friction welding can control the depth of the welding interface. In addition to the connection of the weld itself, a mechanical embedding bite is formed, which can further improve the shear resistance of the friction pad. At the same time, even if there is a dimensional deviation between the thickness of the workpiece and the height of the pad, the distance between the flange of the connection pad and the top plate can be adjusted by controlling the insertion depth, ensuring that the flange presses the longitudinal ribs tightly, ensuring that the longitudinal ribs and the top plate are tightly combined, and lowering the precision requirements for the workpiece.

[0014] Preferably, the friction welding disc has a rotating shaft and a step portion; the step portion is located at one end of the rotating shaft portion, and the diameter of the step portion is greater than the diameter of the rotating shaft portion. By using a stepped friction welding disc, the workpiece is pressed by the step at the outer end of the disc and embedded in the friction welding to form a mechanical embedding force. The friction welding with stable performance is used to weld not only the top plate but also the longitudinal ribs, thereby increasing the welding area, so that the structure can be fully used for structural parts and has high fatigue resistance.

[0015] Preferably, a through hole extending in the axial direction is provided in the middle of the friction welding disc. The centerline speed of the traditional circular end face is low, and the welding performance is weaker than that of the periphery, which becomes a hidden danger point of welding defects. The development of the defect may cause the welding disc to fail. The hole is opened at the part with a lower centerline speed of the circle center, which avoids the existence of the area with weaker welding performance in the center. At the same time, after welding, the top plate base material and the circular hole in the welding disc are embedded with each other, which significantly improves the shear resistance. At the same time, the opening in the middle of the welding disc can be used as a channel for discharging excess molten material and impurities. The molten material and impurities of friction welding are smoothly squeezed out through the hole, so that the welding section of friction welding is pure and free of impurities, and the welding quality is good.

[0016] Preferably, the outer corner radius R of the web and flange is 0.5t to 0.75t. The setting of this corner radius range reduces the probability of the longitudinal rib web deforming inwards. Since there is no special support structure in the longitudinal rib cavity, inward buckling will cause the rib wall to be unstable, and the above corner radius increases the probability of the rib wall deforming outwards, especially at the intersection of the longitudinal rib and the transverse rib, where the force is greater. The outward deformation of the above-mentioned part is constrained by the transverse rib web, thus ensuring the stability of the longitudinal rib web and the stable performance of the longitudinal rib function. When R is less than this range, the longitudinal rib will easily produce forming defects due to the limited creep of the parent material, and the defect is located inside the rib, which is not easy to check, find, and repair. When R is greater than 0.5t, the defect is significantly reduced. When R is greater than 0.75t, the effective supporting cross-section of the longitudinal rib wall in the projection direction of its extension is reduced, and the rib wall generates a large rotational torque. When the torque exceeds the critical point of stability corresponding to the height-to-thickness ratio of the rib wall, the longitudinal rib wall will easily become unstable. The present application effectively avoids the occurrence of the above-mentioned risks.

[0017] Preferably, the longitudinal rib is a closed rib. For closed longitudinal ribs, due to the outward movement of the welds on both sides, the actual spacing between adjacent longitudinal ribs becomes smaller, the span of the top plate is reduced, and the longitudinal ribs can break through the restrictions of height-to-thickness ratio, length-to-thickness ratio, and width-to-thickness ratio, develop into large longitudinal ribs, increase the moment of inertia of a single rib, and not only reduce the number of transverse rib nodes, welds, and parts, but also have better overall structural continuity and are insensitive to the lower structure.

[0018] Preferably, the ratio of the longitudinal rib height to the plate thickness is greater than 45. The traditional design mainly limits the performance of the longitudinal ribs due to the sensitivity of the welds between the top plate and the longitudinal ribs. After solving the problem of the sensitivity of the welds between the top plate and the longitudinal ribs, the present application breaks through the limitation of the height-to-thickness ratio of the longitudinal ribs in the traditional structure, and the orthotropic steel bridge deck adopts thin rib walls and thick lower flanges with higher performance tall longitudinal ribs.

[0019] Preferably, the longitudinal rib is an open rib. The connection method between the open rib with flange and the top plate is diversified, the designability is stronger, and it is particularly suitable for the application of the cantilever section of the bridge.

[0020] Compared with the prior art, the above technical solution has the following beneficial effects:

[0021] 1. The embodiment of the present application proposes a novel long-angle connection longitudinal rib and bridge deck structure, which is creatively connected by a bent flange and controls the distance from the connection point of the longitudinal rib and the top plate to the fulcrum, thereby ensuring the connection strength and moving the connection point away from the fulcrum. The distance from the connection point to the fulcrum is greatly increased compared with the traditional structure, and the ratio of the force arm from the external force to the fulcrum to the force arm from the tension at the weld to the fulcrum is greatly reduced, thereby reducing the stress and stress amplitude at the weld, and the weld can bear greater free coordinated strain. The structural details of this novel connection between the longitudinal rib and the top plate significantly and effectively reduce the probability of fatigue cracking of the weld at the connection between the top plate and the longitudinal rib.

[0022] 2. Different from the traditional structure, the longitudinal ribs of this application have no welding at the fulcrum, and the fulcrum only bears pressure. The supporting compressive stress of the longitudinal ribs and the top plate is decomposed and borne by the parent material of the formed corner. The welds far away from the fulcrum bear the shear force, separating the force of the fulcrum and the weld, making the force simpler and clearer, reducing the stress and stress amplitude at the weld, and further improving the fatigue resistance.

[0023] 3. The fulcrum, i.e. the opening and closing rotation point of the longitudinal rib web, is replaced by the weld of the traditional structure by the base material corner with high fatigue resistance, which strengthens the coordinated connection between the spaced connection points, especially improves the energy absorption effect when the connection point is subjected to force, and the rib corner's own anti-torsion and anti-bending performance is improved. The above-mentioned far-angle connection structure of this patent realizes the ideal beneficial effect that the base material angle of the longitudinal rib is freely and coordinatedly changed after the top plate is subjected to force, but is insensitive or insensitive to the connection points located on the distant flanges.

[0024] 4. After solving the problem of sensitive welds between the top plate and the longitudinal ribs, the longitudinal ribs in the embodiment of the present application break through the constraints of the height-to-thickness ratio, length-to-thickness ratio, and width-to-thickness ratio of the longitudinal ribs. More cross-sections can be used for the parts that bear the main stress and the parts of the cross beams, and the two-way performance of the entire structure tends to be balanced and taken into account. At the same time, a double-layer plate is formed at the joint between the flange and the top plate, which partially increases the thickness of the top plate. Under the same force conditions, a thinner steel plate can be used for the top plate, further improving material efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the welding of the longitudinal ribs and the top plate of the bridge deck in the prior art of this application;

[0026] Figure 2 This is a schematic diagram of the three-dimensional structure of the bridge deck structure of Example 1 of the present application;

[0027] Figure 3 This is a schematic diagram of the three-dimensional structure of a longitudinal rib connected at a far corner in Example 1 of the present application;

[0028] Figure 4 This is a cross-sectional view of a longitudinal rib connected at a far corner in Example 1 of the present application;

[0029] Figure 5 for Figure 4 A partial enlarged view of

[0030] Figure 6 A schematic diagram of friction welding used in the bridge deck structure of Example 2 of the present application;

[0031] Figure 7 This is a schematic diagram of the structure of the friction pad in Example 2 of the present application;

[0032] Figure 8 A schematic diagram of a bridge deck structure connected by bolts in Example 3 of the present application;

[0033] Fig. 9 This is a schematic diagram of the structure of the open longitudinal ribs connected at the far corners in Example 4 of the present application.

[0034] Figure numerals: 1. top plate; 2. longitudinal rib; 21. web; 22. flange; 23. connection hole; 3. connection piece; 31. rotation shaft; 32. step portion; 33. through hole; 34. end face; 4. concrete layer. DETAILED DESCRIPTION

[0035] The present application is further described below in conjunction with the accompanying drawings. It should be noted that in the description of the present application, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present application.

[0036] Embodiment 1:

[0037] like Figure 2 As shown, a bridge deck structure includes a top plate 1 and longitudinal ribs 2. The top plate 1 has a top surface and a bottom surface, and a paving layer such as concrete or asphalt is laid on the top surface to bear external wheel loads. A plurality of longitudinal ribs 2 are arranged on the bottom surface of the top plate 1, and the longitudinal ribs 2 are parallel to the length direction of the top plate 1, and a plurality of longitudinal ribs 2 are arranged side by side and spaced apart.

[0038] like Figure 3 , 4 As shown, the longitudinal rib 2 is a closed rib, and the longitudinal rib 2 includes a pair of axisymmetric flanges 22 and a web 21. The flange 22 is located at the end of the web 21, and the flange 22 and the web 21 have a rotation angle α, 90°≤α≤135°; the flange 22 has a plurality of connection holes 23 arranged at intervals along the length direction of the longitudinal rib 2. The flange 22 and the web 21 are formed by bending or rolling a flat steel plate of equal thickness. Some existing longitudinal ribs use hot rolling and other processes to upset the ends of the webs, which is costly, and the hot rolling roughening is affected by the thickness of the plate, the width of the end upset is limited, and the weld cannot be far away from the corner sensitive area, and the fatigue cracking problem cannot be fundamentally solved.

[0039] like Figure 2 The bridge deck structure shown in the figure also includes a connector 3. The flange 22 of the longitudinal rib 2 fits the bottom surface of the top plate 1, and the connector 3 is arranged in the connection hole 23, and the connector 3 fixes the top plate 1 and the longitudinal rib 2. After the top plate 1 is connected with the longitudinal rib 2, the web 21 intersects with the top plate 1, which plays a reinforcement role. In this embodiment, the web 21 of the longitudinal rib 2 intersects with the top plate 1 at an angle, and the web 21 can bear both longitudinal force and lateral force. Figure 4, the intersection of the center line of the thickness of the web 21 and the plane where the top surface of the flange 22 is located is C. Since the bottom surface of the top plate 1 fits with the top surface of the flange 22 after connection, point C is also the intersection of the center line of the thickness of the web 21 and the bottom surface of the top plate 1. The shortest distance from point C to the connection hole 23 is d1, and the web thickness is t, t≤d1≤5t. It can be seen from the various load conditions of the longitudinal rib 2 that no matter the deflection of the top plate 1, the high probability of eccentric wheel load, torsion or distortion, and the out-of-plane deformation caused by various working conditions, mid-span torsion effect, mid-span rolling effect, etc., a basic strain will be caused, that is, the angle between the web 21 of the longitudinal rib 2 and the top plate 1 welding position is constantly opening and closing, also known as the distortion angle change, which constantly acts near the weld root or weld toe, and the rotation center or fulcrum of the distortion angle change is point C.

[0040] The embodiment of the present application proposes a novel far-angle connection bridge deck structure, in which the connection point between the longitudinal rib 2 and the top plate 1 is located away from the fulcrum, and the stress and stress amplitude at the connection point are adjusted by controlling the shortest distance d1 from point C to the connection hole 23, that is, the force arm of the connection part. When d1<t, the lower limit of the far-angle net distance (d1-0.5t) is only 0.5t. At this time, the stress at the connection part increases during rotation. Conversely, the upper limit of the far-angle net distance (d1-0.5t) will reach 4.5t. At this time, the connection distance is too large, and the connection strength between the longitudinal rib and its connection point is significantly weakened, causing the longitudinal rib to be distorted and roll, and failing to fix the longitudinal rib well.

[0041] The above performance advantages can be derived from the following calculation analysis:

[0042] Taking the longitudinal rib with a conventional opening of 300mm and a rib thickness of 8mm as an example, when the traditional longitudinal rib is connected to the top plate, the end pier is thickened to 10mm and the blunt edge width is 2mm, then the horizontal width of the top surface of the weld is 9mm, and the central rotation point of the welding angle opening and closing is theoretically located at the intersection of the longitudinal rib web 21 and the top plate bottom plate, and the distance from the center point to the weld toe is 9 / 2=4.5mm. When the top plate is loaded, the center point of the resultant force of the external force is located at the center of the longitudinal rib, that is, the distance to the fulcrum is 300 / 2=150mm. The force lever arm ratio at the weld toe is: (150-4.5): 4.5≈32:1. Near the rotation center of the rib wall, that is, near the rotation fulcrum, assuming that the distance from the fulcrum to the weld root is 1mm (actually much less than 1mm, or even 0), the force lever arm ratio at the weld root is: (150-4.5): 1=145.5:1. It can be seen that the force on the traditional longitudinal rib weld has a magnification factor of at least 32 to 145 times that of the external force.

[0043] In the embodiment of the present application, assuming that the minimum distance d1 between the connecting hole and the fulcrum point C is t, and the net distance at the far corner is d1-0.5t=4mm, then the lever arm ratio of the connecting part under load is: (150-4): 4≈36.5:1; assuming that the minimum distance d1 between the connecting hole and the fulcrum point C is 5t, and the net distance at the far corner is d1-0.5t=36mm, then the lever arm ratio of the connecting part under load is: (150-4): 36≈4.06:1.

[0044] It can be seen that in the embodiment of the present application, the ratio of the force arm from the external force to the fulcrum to the force arm from the tension at the weld to the fulcrum is greatly reduced compared with the traditional longitudinal rib structure, and the larger d1 is, the lower the ratio is. Therefore, the stress and stress amplitude at the connection position of the structure are reduced. If welding is performed at this location, the weld can bear a larger free coordinated strain. This new structural detail of the connection between the longitudinal rib and the top plate significantly reduces the probability of fatigue cracking of the weld at the connection between the top plate and the longitudinal rib, and improves the fatigue resistance.

[0045] At the same time, since there is no welding at the position of point C in the embodiment of the present application, the fulcrum only bears pressure, and the supporting compressive stress of the longitudinal rib 2 and the top plate 1 is decomposed and borne by the parent material of the formed corner, and the weld or connecting part at the connection away from the fulcrum point C bears the shear force, which separates the force of the two, makes the force more concise and clear, further reduces the stress and stress amplitude at the connection position, and improves the fatigue resistance.

[0046] Furthermore, the embodiment of the present application arranges a wider flange 22 at the upper edge of the longitudinal rib 2, which not only increases the cross-sectional moment of inertia of the longitudinal rib 2, but also reduces the actual span of the top plate between adjacent longitudinal ribs, which can break through the constraints of the height-to-thickness ratio, the length-to-thickness ratio, and the width-to-thickness ratio, so that the height of the rib is increased, the economy is increased, and more cross-sections can be used for the parts that bear the main stress and the parts of the cross beam, and the two-way performance of the entire structure tends to be balanced and taken into account; the flange 22 forms a double-layer plate at the joint with the top plate 1, which partially increases the thickness of the top plate 1, and under the same force conditions, the top plate 1 can use a thinner steel plate, further improving material efficiency.

[0047] like Figure 4 , 5 As shown, if point C is empty or the outer corner radius of the web 21 and the flange 22 is too large, it will cause additional bending moment in the longitudinal rib web 21, which is very unfavorable to the stability of the longitudinal rib web 21, and is prone to buckling. It is easy to cause long-term unidirectional stress in the connection part (i.e. long-term tensile stress or long-term compressive stress), which is unfavorable to fatigue of the connection point. At the corner, it is preferred that point C is not empty, that is, point C is inside the top surface of the flange 22.

[0048] At the same time, the outer corner radius R of the web 21 and the flange 22 is preferably 0.5t to 0.75t. When R is less than this range, the longitudinal rib 2 will easily produce molding defects due to the limited creep of the parent material, and the defect is located inside the rib, which is not easy to check, find, and repair. When R is greater than 0.5t, the defect is significantly reduced. When R is greater than 0.75t, the effective supporting cross-section of the longitudinal rib web 21 in the projection direction of its extension is reduced, and the web 21 generates a large rotational torque. When the torque exceeds the critical point of stability corresponding to the height-to-thickness ratio of the web 21, the longitudinal rib web 21 will easily become unstable. This range effectively avoids the occurrence of the above risks.

[0049] like Figure 3 As shown, the connection holes 23 are arranged at unequal intervals along the length direction of the longitudinal ribs. Especially in areas prone to cracking, such as above the transverse ribs, the local fatigue strength can be enhanced by closely spaced connectors with small spacing. Compared with the through-length welds of the traditional longitudinal rib top plate connection, the connection through the connection holes can match different stress conditions in the longitudinal direction, and the designability is stronger. At the same time, the side of the flange 22 is not welded to the top plate 1 or is partially welded, leaving maintenance space for subsequent reinforcement.

[0050] Embodiment 2:

[0051] like Figure 6 As shown, in the bridge deck structure of Example 2, the connecting member 3 is a friction welding disc, and the longitudinal rib 2 and the top plate 1 are welded and fixed by friction welding.

[0052] like Figure 6 As shown, the structure of the friction pad matches the shape of the connection hole 23. When connected, the flange 22 fits with the top plate 1, and the friction pad is arranged in the connection hole 23. The friction pad is a rotating body with a rotating shaft 31 and a step 32 in the direction of rotation of the friction pad as the front and the reverse direction as the rear. The step 32 is located at the rear end of the rotating shaft 31 and has a diameter greater than the diameter of the rear end face of the rotating shaft 31. During welding, the friction pad is in the connection hole 23 and is driven by the motor to rotate at a high speed. Friction heat is generated, and the metal in the contact area between the friction pad and the top plate 1 and the longitudinal rib 2 undergoes plastic deformation. At the same time, pressure is applied to the friction pad to weld the longitudinal rib 2 and the top plate 1 together. After welding, the step 32 presses the flange 22 to form a mechanical embedding force. Through the friction welding with stable performance, it is not only welded to the top plate, but also welded to the longitudinal rib, which increases the welding area and improves the connection strength.

[0053] As can be seen from Example 1, since the forces at the fulcrum and the connecting member 3 are separated, the fulcrum is mainly subjected to compressive stress, and the connecting member 3 is mainly subjected to lateral shear force. Therefore, a number of structures for improving the shear resistance are designed in the friction pad:

[0054] First, because the center line speed of the circular end face is low and the outer line speed is high when it rotates, it is easy to cause the center welding performance to be weaker than the periphery, which becomes a hidden danger point of welding defects, such as Figure 7 As shown, a cavity or through hole 33 is provided in the middle of the front end face 34 of the friction pad, and the part with a smaller centerline speed is not rubbed, which avoids the existence of the central area with weaker welding performance. The end face of the pad is opened to form an annular end face, which can not only be embedded with the top plate 1 after welding, but also significantly improve the shear resistance. At the same time, the opening in the middle of the friction pad can be used as a channel for discharging excess molten material and impurities. The molten material and impurities of friction welding are smoothly squeezed out through the hole, so that the welding section of friction welding is pure and free of impurities, and the welding quality is good. If the molten material is squeezed out through the gap between the friction pad and the longitudinal rib 2, it will not only expand the gap between the two workpieces, but also cause some workpieces to be suspended in the air to form defects.

[0055] Secondly, if Figure 6 , 7 As shown, the front end face 34 of the rotating shaft portion 31 is a concave surface that gradually concave inwards along the edge toward the center. Because the outer line speed is larger, the input energy is large, and the melting is fast, while the center line speed is 0, the input energy is small, and the melting is slow, the pure circular plane of the traditional friction welding cannot achieve the effect of deep embedding into the parent material, or the central area limits its deep embedding efficiency. When a concave surface is used that tilts inwards along the edge toward the center of the circle, the edge of the end face becomes the first part to contact the second workpiece during welding. The metal in this area melts first at high temperature, so that the line speed, energy input, and melting speed of the outer side and the center of the circle tend to match; at the same time, the inner concave surface with a certain slope deepens the depth of the outer welding interface embedded in the top plate parent material, further increasing the shear resistance of the friction welding disc. Secondly, the funnel-shaped slope helps the molten metal flow to the middle and squeeze out through the cavity.

[0056] like Figure 6 , 7 As shown, the rotating shaft 31 is conical. When the cylindrical welding disc rotates, the eccentric swing of the rotating shaft and the shrinkage effect of the welding surface when stopping make the weld interface present a tensile stress state, which is not conducive to the improvement of fatigue performance. The welding disc with a conical slope and the side wall of the opening form a natural pressure carrier. Its appropriate slope can increase the pressure on the side wall geometrically, thereby improving the welding performance. At the same time, the length of the rotating shaft 31 is slightly greater than the thickness of the flange 22, ensuring that the welding interface formed by the friction welding disc and the top plate 1 after welding is located inside the top plate 1, and at least the distance d2 embedded in the top plate 1 is greater than or equal to 2mm, further improving its shear resistance.

[0057] In the embodiment of the present application, the longitudinal rib is fixed to the top plate through friction welding by opening a connecting hole in the middle of the flange 22 at the upper edge. The center of the welding position is located at the center of the welding pad, so that the center of the weld in Example 1 is far away from the web 21 and the rotation fulcrum of the longitudinal rib. The weld is far away from the force-sensitive area, the stress and stress amplitude borne by the weld are reduced, and it can bear greater free coordinated strain.

[0058] Secondly, the multiple longitudinally spaced welding pads of the present application form independent welding islands, which avoid the shortcomings of poor fatigue resistance and easy extension and development of cracks in traditional fillet welds. The island chain structure is formed between the welding islands through the workpiece's own rigidity, which is not only conducive to the formation of the overall structure, but also utilizes the strain of the parent material between the welding islands to cut off the probability of crack development between the welding islands. Furthermore, since the top plate of the steel bridge top plate is a structural load-bearing member, opening a hole in the top plate will weaken the rigidity of the top plate. Example 1 of the present application uses friction welding pads for welding, changing the traditional end face welding of the longitudinal rib and the top plate to face-to-face welding, so that there is no need to increase the cross-section of the weld by thickening the upper edge of the longitudinal rib web or double-sided welding. The welding area and capacity can be changed by adjusting the width of the flange plane and the size of the welding pad, and the welding quality is more controllable.

[0059] The embodiment of the present application utilizes a friction welding disk as a third intermediate, and the welding disk is rotationally welded and welded through the pre-opened holes in the longitudinal rib flange and the bottom surface of the top plate, thereby avoiding opening holes in the top plate. Especially in the steel bridge deck structure, the top plate 1 is a component that directly bears the load. The existing top plate 1 is usually a 14-18mm thick steel plate. Opening a hole in the top plate 1 will greatly weaken its rigidity and strength. The far-angle welding structure adopted in the embodiment of the present application does not require opening holes in the top plate, and can also effectively solve the fatigue problem of the connection between the top plate and the longitudinal rib.

[0060] Moreover, through the intermediate welding plate, only a very small amount of energy needs to be input to rotate it, so as to achieve the purpose of welding two large workpieces, especially long, large, heavy workpieces, and non-circular workpieces, which significantly expands the application scope of friction welding and makes it possible to apply this high-end welding process to common metal components such as bridges. Compared with traditional fusion welding, friction welding belongs to solid-state welding. During welding, impurity pores are broken and squeezed out. The initial defect of the weld is one of the main factors of fatigue cracking. Friction welding has high welding strength and good fatigue resistance, which can effectively improve the fatigue resistance of steel bridge decks.

[0061] At the same time, in comparison with the welding volume of traditional structures, the welding volume of this welding structure and the general longitudinal rib welding volume is 2.19:0.99 per square meter of weld length, and the converted weld length is reduced by 55%. Due to the embedding effect, the shear bearing capacity of a 36mm diameter welding pad is more than 450KN, and the tensile strength exceeds the strength of the parent material. The traditional structure is mainly limited by the sensitivity of the top plate and the longitudinal rib weld, which limits the performance of the longitudinal rib. In fact, the 6mm thick longitudinal rib wall, under the condition of stable lower support, the ultimate load of the longitudinal rib instability can reach more than 900KN. After the sensitive problem of the welds between the top plate and the longitudinal ribs of the bridge deck structure of the present application is solved, the design of the longitudinal ribs breaks through the limitation of the traditional structure that the height-to-thickness ratio of the longitudinal ribs does not exceed 40:1. In addition, the welds on both sides of the closed ribs are moved outward, the actual spacing between adjacent longitudinal ribs becomes smaller, and the span of the top plate is reduced. The longitudinal ribs can break through the constraints of the height-to-thickness ratio, length-to-thickness ratio, and width-to-thickness ratio. The ratio of the height of the longitudinal rib 2 to the plate thickness exceeds 45:1, which increases the height of the ribs and the economy, so that more cross-sections can be used for the parts that bear the main stress and the parts of the cross beams, and the two-way performance of the entire structure tends to be balanced and taken into account.

[0062] As shown in the table below, the rib height of a 6mm thick thin-walled rib can be more than 320mm, and the height-to-thickness ratio exceeds 50:1; compared with traditional longitudinal ribs, the moment of inertia of thin-walled high ribs is significantly improved. When the longitudinal rib spacing of orthotropic steel bridge decks increases, it brings advantages such as reducing transverse rib nodes, reducing welds, and reducing the number of parts. When the longitudinal rib spacing increases and the denser transverse rib spacing is basically similar, the bidirectional performance of the steel bridge deck is close to that of the bidirectional plate, and the force transmission is more uniform.

[0063]

[0064] Embodiment 3:

[0065] like Figure 8 As shown, this embodiment provides a steel-concrete composite bridge deck structure, which is different from embodiment 2 in that the connecting member 3 is a bolt assembly, the top plate 1 has a hole, and the top plate 1 and the longitudinal rib 2 are fixedly connected by the bolt assembly. Different from the steel bridge deck structure of embodiment 2, the composite structure bridge deck will lay a high-performance concrete layer 4 on the top surface of the top plate 1 to thicken the top plate and bear the load. Through the bolt connection, the anchoring effect with the concrete can be increased, and the bonding strength between the steel plate and the concrete can be improved.

[0066] Embodiment 4:

[0067] The difference between this embodiment and the first embodiment is that the longitudinal rib 2 is an open rib, such as Fig. 9 The longitudinal rib 2 shown includes a web 21 and a flange 22 formed by integral bending. The angle α between the web 21 and the flange 22 is 90°. The open rib with the flange 22 is more designable and has a self-flange lower flange 24 at the bottom of the open rib.

[0068] The above is a preferred implementation of the present application. A person skilled in the art may make several modifications and improvements without departing from the principle of the present application, and these modifications and improvements shall also be deemed as within the protection scope of the present application.

Claims

1. A far-angle connection bridge deck structure, comprising a far-angle connection longitudinal rib, comprising at least one web (21) and a flange (22), wherein the flange (22) is located at the end of the web (21), the longitudinal rib (2) is formed by bending or rolling a flat steel plate, the flange (22) and the web (21) have a rotation angle α, 90°≤α≤135°, characterized in that: The flange (22) is provided with a plurality of connection holes (23); the intersection point of the center line of the thickness of the web (21) and the plane where the top surface of the flange (22) is located is C; the shortest distance from point C to the connection hole (23) is d1; the web thickness is t, t≤d1≤5t; and point C is inside the top surface of the flange (22); the flange (22) is fitted with the bottom surface of the top plate (1); a connection piece (3) is arranged in the connection hole (23); the longitudinal rib (2) and the top plate (1) are fixedly connected via the connection piece (3); the connection piece (3) is a friction welding disc, and the friction welding disc is used to fix the longitudinal rib (2) and the top plate (1) by means of rotary friction welding.

2. The far-angle connection bridge deck structure according to claim 1, characterized in that: The end surface (34) of the friction welding disk close to the top plate (1) is an inner concave surface.

3. The far-angle connection bridge deck structure according to claim 1, characterized in that: The friction pad is embedded in the top plate (1), and the distance of the friction pad embedded in the top plate (1) is d2, where d2 is ≥ 2 mm.

4. The far-angle connection bridge deck structure according to claim 1, characterized in that: The friction welding disk comprises a rotating shaft portion (31) and a step portion (32); the step portion (32) is located at one end of the rotating shaft portion (31), and the diameter of the step portion (32) is greater than the diameter of the rotating shaft portion (31).

5. The far-angle connection bridge deck structure according to claim 1, characterized in that: A through hole (33) extending in the axial direction is provided in the middle of the friction welding disc.

6. The far-angle connection bridge deck structure according to claim 1, characterized in that: The outer corner radius R of the web (21) and the flange (22) is 0.5t to 0.75t.

7. The far-angle connection bridge deck structure according to claim 1, characterized in that :: The longitudinal rib (2) is a closed rib.

8. The far-angle connection bridge deck structure according to claim 1, characterized in that: The ratio of the height of the longitudinal rib (2) to the plate thickness is greater than 45.

9. The far-angle connection bridge deck structure according to claim 1, characterized in that: The longitudinal ribs (2) are open ribs.

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