A longitudinal rib and a welding structure thereof with a top plate

Abstract

The present application discloses a longitudinal rib and a welding structure with a top plate, which solves the problem that fatigue cracking easily occurs in the straight weld between the longitudinal rib and the top plate in the prior art. The key points of the technical solution are to provide a longitudinal rib, wherein the longitudinal rib includes at least one web, the upper edge of the web has an ear plate folded to one side, and the web and the ear plate have a rotation angle β, 90°≤β<134°; the outer end of the ear plate is an outer edge, the length of the outer edge is greater than the longitudinal length of the longitudinal rib, and the narrowest width of the ear plate is L, which is greater than 2 times the thickness of the web plate. At the same time, a welding structure of the longitudinal rib and the top plate is provided. While the present application increases the virtual width of the weld, since there are welds in the longitudinal and transverse directions in the plane, the weld's ability to withstand complex isotropic loads is improved, and the weld is located at the outer edge, away from the stress-sensitive area, which greatly reduces the probability of fatigue cracking of the weld.

Description

Technical Field

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

[0002] Orthotropic steel bridge deck is a commonly used bridge deck structure for roads and railways. It is a bridge deck structure that is connected into a whole by welding multiple side-by-side longitudinal ribs, multiple side-by-side transverse ribs and panels to jointly bear the vehicle load. It has unique advantages such as light weight, low structural height, good integrity and large load-bearing capacity, and is widely used around the world.

[0003] Orthotropic steel bridge decks also have many drawbacks. A large number of cracks and fatigue phenomena have occurred in orthotropic bridge decks all over the world, and these are the main causes of various common problems such as rutting, longitudinal and transverse cracks in the bridge pavement layer. These common problems have become a world-class stubborn problem in its nearly 70 years of application, and no perfect solution has been found for many years.

[0004] Among them, the structural details of the longitudinal rib and the top plate are one of the typical fatigue-prone parts in modern orthotropic steel bridge deck structures. Statistical analysis of relevant literature shows that the number of fatigue cracks in the welding details of the longitudinal rib top plate of the steel bridge deck accounts for about 45%, and the probability of occurrence is about 30%. The existing welding methods between the longitudinal rib and the top plate include fillet welding, single-sided welding, double-sided welding, etc.

[0005] The existing method has the following problems:

[0006] Regardless of whether it is the traditional single-sided welding or the double-sided welding proposed in recent years, the welds of the traditional longitudinal ribs and top plates are all continuous long straight welds with a small welding area and are eccentric welds. Under the action of local wheel loads, the longitudinal ribs and panels will produce "drum-shaped" out-of-plane deformation, so the panel deformation is large and the stress is high. During the operation period of the bridge, the weld is located at the corner of the panel and the longitudinal rib web, and it is frequently subjected to large local tensile stresses and repeated cyclic loads, so fatigue cracking is very likely to occur.

[0007] Moreover, once cracks appear in a long straight weld, they will extend and expand along the direction of the weld. In addition, there is an unwelded area at the weld root of the existing welding method, forming a natural crack. The crack develops from the weld root and expands in the thickness direction of the roof. Since the top surface or upper surface of the roof is covered with asphalt and other coverings, such cracks are not easy to be found in the initial stage. Once found, they are often large cracks, which are not only extremely harmful, but also difficult to repair cracked roofs, and often require traffic restrictions, affecting the use of the bridge.

[0008] In order to increase the weld area, Deng Wenzhong and others proposed a U-rib with upset at the upper end of the web. The cost of local upsetting is high, and the upsetting width is limited, and it cannot fundamentally solve the fatigue problem of the welding part. Summary of the invention

[0009] In order to address the defects of the prior art that the straight welds between the longitudinal ribs and the top plate are prone to fatigue cracking, the present application provides a longitudinal rib with an ear plate folded at the end, in which the outer edge of the ear plate is larger than the longitudinal length of the longitudinal rib and is welded to the top plate along the outer edge of the ear plate. This increases the virtual width of the weld. At the same time, since there are welds in the longitudinal and transverse directions in the plane, the weld's ability to withstand diverse strains of complex isotropic loads is improved. The weld is located at the outer edge, away from stress-sensitive areas, which greatly reduces the probability of weld fatigue cracking.

[0010] In order to achieve the above application purpose, this application adopts the following technical solutions:

[0011] The first aspect of the present application provides a longitudinal rib, the longitudinal rib comprises at least one web, the upper edge of the web has an ear plate folded to one side, the web and the ear plate have a turning angle β, 90°≤β≤134°; the outer end of the ear plate is an outer edge, the side length of the outer edge is greater than the longitudinal length of the longitudinal rib; the narrowest width of the ear plate is L, L is greater than 2 times the thickness of the web plate, the outer edge of the ear plate is provided with a plurality of notches, the notches are of a closed type, that is, the opening spacing d of the notches is less than the spacing between the inner walls of the notches, and the opening spacing d is slightly less than or equal to the width of two welds. By providing the notches on the ear plate, the edge of the notch increases the length of the outer edge, not only can welding be performed on the edge of the ear plate, but the weld can penetrate into the fitting surface of the ear plate and the top plate, develop vertically and horizontally, so that the ear plate and the top plate form a welding similar to the overlap of the surface and the surface, and the welding area is increased. A smaller opening size d is used, preferably d is slightly smaller than or equal to the width of two welds. After welding, the opening of the notch is closed by the weld, and a closed annular weld can be formed inside the ear plate.

[0012] Preferably, the notch is in an "Ω" shape.

[0013] Preferably, the notches are arranged at unequal intervals along the length direction of the longitudinal rib. Since the longitudinal rib extends longitudinally, the stress conditions in different areas are different at the mid-span, the crossbeam, the support and other positions. The distribution of the longitudinal weld area can be changed by the number of notches, so as to adapt to the local stress conditions. In practical applications, according to the magnitude of the stress, the notches are dense in the area with large stress, and the notches are sparse in the area with small stress.

[0014] Preferably, the longitudinal rib is a closed rib. The closed rib has a large cross-sectional inertia moment, better bending and torsion resistance, and is more widely applicable. At the same time, the welding of the inner weld of the closed rib belongs to the welding in a narrow space, which is difficult to weld. The longitudinal rib and the top plate of the present application are continuously welded at the outer edge of the ear plate. While the weld length per unit longitudinal rib length is increased, the welding difficulty is greatly reduced, and it is also convenient for subsequent inspection and maintenance.

[0015] Preferably, the longitudinal ribs are open ribs.

[0016] On the other hand, the present application provides a welding structure of longitudinal ribs and a top plate, including a top plate, the top plate having a top plate lower surface, and also including any of the longitudinal ribs described above, the longitudinal ribs are fixedly connected to the top plate, the ear plates are in contact with the lower surface of the top plate, and the longitudinal ribs and the top plate are fixedly connected by welding along the outer edge of the ear plates.

[0017] Compared with the prior art, the longitudinal ribs and the welding structure with the top plate using the above technical solution have the following beneficial effects:

[0018] 1. The connection between the longitudinal rib web and the top plate in the embodiment of the present application breaks through the limitations of the traditional T-joint. By setting an outward ear plate at the upper end of the longitudinal rib web, and the width of the narrowest part of the ear plate is greater than 2 times the thickness of the web, the position of the connecting weld at the edge of the ear plate is far away from the intersection of the center line of the rib wall and the lower surface of the top plate. When the steel bridge deck is subjected to wheel load, the longitudinal rib bulges and twists. From the cross-section of the bridge deck, it is equivalent to the longitudinal rib web making frequent small swings around the intersection of the center line of the web and the lower surface of the top plate. The embodiment of the present application sets the position of the weld at the outer edge of the ear plate, and the distance from the weld to the swing center is increased, that is, the force arm of the weld is increased, so the stress and stress amplitude of the weld are reduced accordingly, the weld can bear a larger free coordinated strain, and the fatigue resistance of the weld is improved, thereby further reducing the common problem of fatigue cracking.

[0019] 2. The setting of the outward-turned ear plate in the embodiment of the present application makes the welding method of the longitudinal rib and the top plate more diversified. The outer edge of the outward-turned ear plate is set to a non-linear shape, and the straight weld is changed into a curved weld. Compared with the traditional welding method, the weld length of the present application is increased, that is, the welding area per unit length of the longitudinal rib and the top plate is increased, and the virtual width of the weld is increased; and, since the direction of the weld changes along the curve direction, there are welds arranged in two directions in the plane, so that when the weld is subjected to external load, there is always a weld in a favorable direction to bear the external load, avoiding the problem of a single force direction of the straight weld, and improving the diverse strain capacity of the weld to withstand complex isotropic loads.

[0020] 3. At the same time, arc starting and arc ending are defect-sensitive points. This weld structure not only realizes the multi-directional load-bearing of the weld, but also enables continuous welding without stopping, reducing the number of arc starting and arc ending, and avoiding the occurrence of welding defects.

[0021] 4. Furthermore, even if cracks occur in the weld, they are easy to find and prevent in time because they are on the outward-turned ear plates on both sides of the web. Even if the curved weld cracks, the cracks are not easy to extend and expand compared to the straight welds in a single direction, avoiding the problem of unlimited extension of the traditional structural welds once cracks occur, and having a natural crack-stopping effect.

[0022] By opening the notch on the ear plate, the edge of the notch increases the length of the outer edge, so that welding can be performed not only on the edge of the ear plate, but also the weld can penetrate into the fitting surface of the ear plate and the top plate, developing vertically and horizontally, so that the ear plate and the top plate form a similar surface-to-surface overlap welding, and the welding area is increased. A smaller opening size d is used, preferably d is slightly less than or equal to the width of two welds. After welding, the opening of the notch is closed by the weld, and a closed annular weld can be formed inside the ear plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the welding structure of the longitudinal rib and the top plate of Example 1 of the present application;

[0024] Figure 2 This is a schematic diagram of the structure of the longitudinal ribs in Example 1 of the present application.

[0025] Figure 3 This is a schematic diagram of the structure of uneven distribution of longitudinal rib notches in Example 1 of the present application

[0026] Figure 4 This is a schematic diagram of the welding structure of the longitudinal rib and the top plate of Example 2 of the present application;

[0027] Figure 5 This is a schematic diagram of the structure of the longitudinal ribs of Example 2 of the present application;

[0028] Figure 6 This is a schematic diagram of the structure of the embodiment 3 of the present application, in which the outer edge is a sinusoidal longitudinal rib;

[0029] Figure 7 This is a schematic diagram of the structure of the embodiment 3 of the present application, in which the outer edge is a rectangular corrugated longitudinal rib;

[0030] Figure 8 This is a structural schematic diagram of Example 4 of the present application in which the longitudinal ribs are open ribs.

[0031] Reference numerals:

[0032] 1—top plate, 11—lower surface of top plate, 2—longitudinal ribs, 21—web plate, 22—ear plate, 23—outer edge, 24—notch, 25—bottom plate. DETAILED DESCRIPTION

[0033] 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.

[0034] Embodiment 1:

[0035] like Figure 1 As shown, Example 1 of the present application provides an innovative non-linear weld structure of a steel bridge deck longitudinal rib 2 and a top plate 1. The steel bridge deck or orthotropic steel bridge deck comprises a top plate 1, a plurality of longitudinal ribs 2 and a plurality of transverse ribs, all of which are made of steel. The top plate 1 is a steel flat plate, and a paving material such as asphalt or concrete is laid on the top plate to bear the wheel load. A plurality of longitudinal ribs 2 are arranged on the lower surface 11 of the top plate 1, and the longitudinal ribs 2 are welded to the lower surface 11 of the top plate. The overall length direction of the longitudinal ribs 2 is parallel to the length direction of the top plate 1, and the plurality of longitudinal ribs are arranged side by side and spaced apart along the width direction of the top plate 1.

[0036] like Figure 2 As shown, the longitudinal rib 2 is a closed rib, including a pair of symmetrical webs 21, the bottom of the webs 21 are connected by a bottom plate 25, the upper edge of the webs 21 has an ear plate 22 folded outward, and the webs 21 and the ear plate 22 have an angle β, 90°≤β≤134°.

[0037] like Figure 2 The outer end of the ear plate 22 is an outer edge 23, which is a curve formed by a plurality of notches 24 opened on the outer side of the ear plate 22, and the side length of the outer edge 23 is greater than the longitudinal length of the longitudinal rib 2. The narrowest width of the ear plate is L, which is greater than twice the thickness of the web plate.

[0038] The longitudinal rib 2 is connected to the top plate 1 through the ear plate 22. The ear plate 22 fits against the lower surface 11 of the top plate. The longitudinal rib 2 and the top plate 1 are fixedly connected by forming a curved weld along the outer edge 23. Since the ear edge has multiple notches 24, during continuous welding, the weld can penetrate into the inside of the fitting surface of the ear plate 22 and the top plate, so that the ear plate 22 and the top plate 1 form a surface-to-surface overlap welding, and the welding area is increased. Furthermore, since the longitudinal rib 2 extends in the longitudinal direction, the stress conditions in different areas are not the same at the mid-span, beam, support and other positions. Figure 3 As shown, the longitudinal rib 2 is provided with more notches 24 in the area with greater stress, thereby increasing the weld length per unit area, and the open grooves are sparse in the area with less stress. The distribution of the weld area along the longitudinal direction is changed by the number of open grooves, thereby adapting to different longitudinal stress conditions.

[0039] like Figure 2 As shown, the notch 24 is an open notch, that is, the spacing d of the opening of the notch 24 is greater than the distance between the inner walls of the notch 24. The non-linear outer edge 23 formed by the open notch 24 is more convenient to weld during continuous welding due to the larger opening, and the ear plate is easier to process, which is more economical in actual production.

[0040] Traditional longitudinal rib webs and top plates are usually connected by a T-shaped structure, and the upper end of the web is welded to the top plate in the longitudinal direction. Due to structural limitations, the weld formed is a long straight weld, and the welding method is single. The connection between the longitudinal rib web 21 and the top plate 1 in the embodiment of the present application breaks through the limitations of the traditional T-shaped joint. By providing an outward ear plate 22 at the upper end of the longitudinal rib web, the welding method of the longitudinal rib and the top plate is made more diversified. The outer edge 23 of the outward ear plate 22 is set to a non-linear shape, and the straight weld is changed to a curved weld, thereby increasing the virtual width of the weld and the diverse strain capacity of the weld to withstand complex isotropic loads. That is, since the direction of the weld changes along the curved direction, there are welds arranged in two directions in the plane, so that when the weld is subjected to external load, there is always a weld in a favorable direction to bear the external load, thus avoiding the problem of a single force direction for the straight weld.

[0041] Moreover, since the outer edge 23 is arranged in a curve, its length is greater than the length of the longitudinal rib, that is, the length of the weld formed by welding along the outer edge is greater than the traditional straight weld (the length of the weld connected to the traditional longitudinal rib top plate is equal to the length of the longitudinal rib), the weld length is increased, that is, the welding area per unit length of the longitudinal rib and the top plate is increased, the welding strength is improved, and the problem of small welding area between the existing longitudinal rib and the bridge deck and easy fatigue cracking of the weld is solved. Secondly, even if cracks occur in the weld, it is easy to find and maintain in time because the weld is on the outward-turned ear plates on both sides of the web.

[0042] Furthermore, once a curved weld cracks, the crack is not easy to extend and expand because its direction is not single, avoiding the problem of infinite extension and expansion of the crack once a straight weld cracks, and has a natural crack-stopping effect.

[0043] In addition, when the steel bridge deck is subjected to wheel loads, it causes the longitudinal ribs to bulge and twist. From a cross-sectional view, this is equivalent to the longitudinal rib web constantly swinging slightly relative to the top plate, and the center of the swing is the intersection of the center line of the web 21 and the lower surface of the top plate 1. In the embodiment of the present application, since the weld is located on the outside of the ear plate 22 and the narrowest L of the ear plate 22 is greater than twice the thickness of the web plate, the distance from the weld to the center of the swing (also the force arm of the weld) increases accordingly, thereby reducing the stress and stress amplitude of the weld, and improving the fatigue resistance of the weld.

[0044] Embodiment 2:

[0045] like Figure 4 Another welding structure of the longitudinal rib 2 and the top plate 1 shown in the figure is different from that of the first embodiment in that the notch 24 of the longitudinal rib 2 is of a closed type, and the spacing d at the opening of the notch 24 is smaller than the distance between the inner walls of the notch 24. Figure 5 The notch 24 is a longitudinal rib similar to an "Ω" shape. The notch 24 includes a circular hole 241 and an opening 242. The outer edge 23 can be welded by continuous fillet welds, and the size d at the opening of the notch 24 is controlled to be slightly less than or equal to the width of two welds. Figure 4As shown, the opening of the notch 24 is closed by the weld, and the arc starting and arc ending are defect-sensitive points. The present weld structure not only realizes the multi-directional load-bearing of the weld, but also can weld continuously without stopping in one stroke, thereby reducing the number of arc starting and arc ending, and avoiding the occurrence of welding defects. Not only a through-length weld is formed at the edge of the ear, but also independent closed annular welds are formed inside the ear plate 22. The welding method is simple and practical, which effectively solves the common welding problems and forms a higher-performance longitudinal rib and top plate welding structure.

[0046] Embodiment 3:

[0047] like Figure 6 , 7 As shown, the outer edge 23 of the longitudinal rib 2 is a wave curve. Figure 6 is a schematic diagram showing that the outer edge 23 is a sinusoidal waveform, Figure 7 The schematic diagram shows that the outer edge 23 is a sawtooth waveform, and it can also be other waveform curves such as a trapezoidal wave, a triangular wave, etc. After welding, a corrugated weld is formed. Compared with a straight weld, the welding strength, anisotropic force performance, and fatigue cracking resistance of the corrugated weld are greatly improved compared with the straight weld.

[0048] Embodiment 4:

[0049] like Figure 8 As shown, the difference from the previous embodiment is that the longitudinal rib 2 is an open rib, including a web 21 and a lug 22, and the web 21 is perpendicular to the lug 22.

[0050] 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 longitudinal rib, wherein the longitudinal rib (2) comprises at least one web (21), characterized in that: The upper edge of the web (21) has an ear plate (22) folded to one side, and the web (21) and the ear plate (22) have a rotation angle β, 90°≤β≤134°; the outer end of the ear plate (22) is an outer edge (23), and the length of the outer edge (23) is greater than the longitudinal length of the longitudinal rib (2); the narrowest width of the ear plate (22) is L, and L is greater than twice the thickness of the web (21); a plurality of notches (24) are provided on the outer edge of the ear plate (22), and the notches (24) are of a closed type, that is, the opening spacing d of the notches (24) is less than the spacing between the inner walls of the notches (24), and the opening spacing d is slightly less than or equal to the width of two welds.

2. The longitudinal rib according to claim 1, characterized in that: The notch (24) is in the shape of an "Ω".

3. The longitudinal rib according to claim 1, characterized in that: The notches (24) are arranged at unequal intervals along the length direction of the longitudinal rib.

4. The longitudinal rib according to claim 1, characterized in that: The longitudinal ribs (2) are closed ribs.

5. The longitudinal rib according to claim 1, characterized in that: The longitudinal ribs (2) are open ribs.

6. A welding structure of a longitudinal rib and a top plate, comprising a top plate (1), wherein the top plate (1) has a top plate lower surface (11), characterized in that: It also includes the longitudinal rib (2) according to any one of claims 1 to 5, wherein the longitudinal rib (2) is fixedly connected to the top plate (1), the ear plate (22) is in contact with the lower surface (11) of the top plate, and the longitudinal rib (2) and the top plate (1) are fixedly connected by welding along the outer edge (23) of the ear plate (22).

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