Small-spacing rear-trepanning reinforced steel beam and manufacturing method thereof

Abstract

The invention relates to the technical field of constructional engineering, and provides a small-spacing post-trepanning reinforced steel beam and a manufacturing method, the small-spacing post-trepanning reinforced steel beam comprises a beam body and a reinforcing rib group; a plurality of through holes are formed in a web plate of the beam body, and the through holes are arranged in the length direction of the beam body; in the length direction of the beam body, the clear distance between the adjacent through holes is smaller than the beam height of the beam body; the reinforcing rib group is connected to the web plate; and one reinforcing rib group is arranged on one side of the web plate and between the adjacent through holes. The steel beam structure can fill the technical blank of the current design specification based on the engineering actual requirements of the existing steel beam rear through hole frequently encountered during the existing steel beam transformation, building updating or transformation period.

Description

Technical Field

[0001] The invention relates to the technical field of building engineering, and in particular to a small-spacing rear-opening reinforced steel beam and a manufacturing method thereof. Background Art

[0002] Steel beams have the characteristics of high strength, good ductility and excellent seismic resistance, and are widely used in construction, such as high-rise and super-high-rise buildings, large-span space buildings, etc.

[0003] With the widespread application of steel structure buildings, changes in electromechanical and building functions are often encountered during the construction process of steel structure buildings and the renovation of existing steel structure buildings. In order to ensure the indoor net height or improve the indoor net height standard, the transformation of existing steel beams is a better solution, such as adding through holes in the web of the steel beam to allow the electromechanical pipelines to pass through the beam.

[0004] The current design specifications only have the design methods and requirements for steel beam reserved holes, and do not involve how to open holes in steel beams later. There is a lack of design basis for structural steel beams that have been constructed or for reconstruction projects. At the same time, the reserved hole spacing required by the specifications is relatively large, which has great restrictions on engineering design and reconstruction. When encountering small-spacing reserved holes or later holes, how to construct and reinforce to meet the original design requirements becomes an engineering problem.

[0005] Therefore, based on the above technical problems, a small-spacing rear-opening reinforced steel beam and a manufacturing method are needed to meet the actual engineering needs of the rear through holes of existing steel beams. Summary of the invention

[0006] The purpose of the present invention is to provide a small-spacing rear-opening reinforced steel beam and a manufacturing method. The steel beam structure can be modified based on existing steel beams to meet the actual engineering needs of the rear through holes of existing steel beams.

[0007] The present invention provides a small-spacing rear-opening reinforced steel beam, comprising: a beam body and a reinforcing rib group;

[0008] The web of the beam body is provided with a plurality of through holes, and each of the through holes is arranged along the length direction of the beam body;

[0009] Along the length direction of the beam body, the net distance between adjacent through holes is smaller than the beam height of the beam body;

[0010] The reinforcing rib group is connected to the web;

[0011] On one side of the web, a reinforcing rib group is arranged between adjacent through holes.

[0012] Optionally, the reinforcing rib group includes a first reinforcing rib and a second reinforcing rib, the first reinforcing rib and the second reinforcing rib are both connected to the web, and the first reinforcing rib and the second reinforcing rib are cross-arranged.

[0013] Optionally, the reinforcement rib group is connected to a single side of the web.

[0014] Optionally, the ends of the first reinforcing rib and the second reinforcing rib are in non-connected fit with the wing plate of the beam body.

[0015] Optionally, the thickness of the first reinforcement rib and the second reinforcement rib is T=t+a;

[0016] The t is equal to the web thickness of the beam body, and the a is equal to 0 to 2 mm.

[0017] Optionally, the width of the first reinforcing rib and the second reinforcing rib is less than or equal to half of the wing plate width of the beam body.

[0018] Optionally, one of the first reinforcing rib and the second reinforcing rib has an angle of 45° to 60° with the length direction of the beam body, and the other has an angle of 120° to 135° with the length direction of the beam body.

[0019] Optionally, the diameter of the through hole is less than or equal to one third of H, where H is the beam height of the beam body.

[0020] The present invention also provides a method for manufacturing a small-spacing rear-opening reinforced steel beam, comprising the following steps:

[0021] Provide temporary support for the beam;

[0022] Through holes are provided on the web of the beam body, and along the length direction of the beam body, the net distance between adjacent through holes is less than the beam height of the beam body;

[0023] The reinforcing rib group is welded to the web of the beam body, and one reinforcing rib group is arranged between adjacent through holes on one side of the web;

[0024] Remove temporary supports.

[0025] Optionally, the through hole is formed by magnetic drilling or plasma cutting;

[0026] and / or, the reinforcing rib group is connected to the web of the beam body by welding, using double-sided fillet welds, and the weld height is greater than or equal to 0.7T, where T is the thickness of the reinforcing rib group;

[0027] and / or, the reinforcing rib group is connected to a single side of the web;

[0028] And / or, the reinforcing rib group includes a first reinforcing rib and a second reinforcing rib, the first reinforcing rib and the second reinforcing rib are both connected to the web, and the first reinforcing rib and the second reinforcing rib are cross-arranged; one of the first reinforcing rib and the second reinforcing rib is a full-length oblique rib, and the other is a segmented oblique rib, the full-length oblique rib is an integral oblique rib, and the segmented oblique rib is a two-segmented oblique rib, the two-segmented oblique ribs are respectively located on both sides of the full-length oblique rib, and are in a non-connected fit with the full-length oblique rib;

[0029] And / or, the end portions of the reinforcing rib group are in non-connected contact with the wing plates of the beam body.

[0030] In summary, the small-pitch rear-opening reinforced steel beam comprises: a beam body and a reinforcing rib group; the web of the beam body is provided with a plurality of through holes, and each of the through holes is arranged along the length direction of the beam body; along the length direction of the beam body, the net distance between adjacent through holes is less than the beam height of the beam body; the reinforcing rib group is connected to the web; on one side of the web, a reinforcing rib group is arranged between adjacent through holes.

[0031] The above-mentioned small-spacing rear-opening reinforced steel beam provides a small-spacing rear-opening reinforcement method on the existing steel beam. After adopting the opening and reinforcement method of the present invention, the bearing capacity and stiffness of the steel beam can still meet or be close to the original design requirements, and can effectively solve the actual engineering needs of the rear opening of the steel beam web. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of a small-spacing rear-opening reinforced steel beam according to an embodiment of the present invention;

[0033] Figure 2 In one embodiment Figure 1 Schematic diagram of the Ⅰ-Ⅰ cross-sectional structure;

[0034] Figure 3 In another embodiment Figure 1 Schematic diagram of the Ⅰ-Ⅰ cross-sectional structure.

[0035] Among them, in the attached drawings:

[0036] 10- beam body; 101- web plate; 102- flange plate;

[0037] 11-through hole;

[0038] 20-reinforcement rib group; 21-first reinforcement rib; 22-second reinforcement rib;

[0039] a-first direction; b-second direction; c-third direction. DETAILED DESCRIPTION

[0040] The following is a further detailed description of the small-pitch rear-opening reinforced steel beam and the manufacturing method proposed by the present invention in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0041] As used in the present invention, the singular forms "one", "an" and "the" include plural objects, the term "or" is usually used to include the meaning of "and / or", the term "several" is usually used to include the meaning of "at least one", and the terms "at least two" or "multiple" are usually used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" can explicitly or implicitly include one or at least two of the features. In addition, as used in the present invention, "installed", "connected", "connected", and one element "set" on another element should be understood in a broad sense, usually only indicating that there is a connection, coupling, matching or transmission relationship between the two elements, and the connection, coupling, matching or transmission between the two elements can be direct or indirect through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, one element can be in any orientation such as inside, outside, above, below or on one side of another element, unless the content clearly indicates otherwise. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, directional terms such as above, below, up, down, upward, downward, left, right, etc. are used with respect to the exemplary embodiments as they are shown in the figures, with the upward or upper direction toward the top of the corresponding figure, and the downward or lower direction toward the bottom of the corresponding figure.

[0042] Combination Figure 1 and Figure 2 As shown, the first direction a corresponds to the length direction of the beam body 10 , the second direction b corresponds to the width direction of the beam body 10 , and the third direction c corresponds to the height direction of the beam body 10 .

[0043] This embodiment provides a small-spacing rear-opening reinforced steel beam, including: a beam body 10 and a reinforcement rib group 20.

[0044] Combination Figure 1 and Figure 2 As shown, in this embodiment, the beam body 10 is an I-beam, and the beam body 10 includes a web 101 and two flanges 102 , the web 101 is connected between the two flanges 102 , and the web 101 and the flanges 102 are connected along the middle of their widths.

[0045] The web 101 of the beam body 10 is provided with a plurality of through holes 11, and the through holes 11 are arranged along the length direction (first direction a) of the beam body 10. The through holes 11 are provided on the beam body 10 in the existing building, that is, the through holes 11 are provided in a post-drilling manner (not reserved in the process of manufacturing the steel beam).

[0046] The through hole 11 is cut by a magnetic drill or plasma cutting process. The position of the through hole 11 should avoid the stress concentration position of the beam body 10 (for example, the net distance between the through hole 11 and the stress concentration position is H, where H is the beam height of the beam body 10), and the through hole 11 should be cut along the length direction of the beam body 10 ( Figure 1 In the first direction a), the minimum clear distance between the through hole 11 and the end of the beam body 10 is 1.5H, where H is the beam height of the beam body 10. The above-mentioned clear distance refers to the minimum distance between the edge of the through hole 11 and the target position. By selecting the position of the opening 11, the position of the opening 11 can be avoided from the position where the force of the beam body 10 is concentrated, so as to ensure the overall structural stability and mechanical properties of the beam body 10 after the opening.

[0047] In this embodiment, the use scenario of opening holes with small spacing is mainly targeted, so along the length direction of the beam body 10 ( Figure 1 The first direction a), the net distance L between the adjacent through holes 11 is less than the beam height H of the beam body 10, where H is the height of the beam body 10 along the height direction ( Figure 2 Dimension in the third direction c).

[0048] Since the provision of the through hole 11 will affect the structural strength of the beam body 10 itself, the existing beam body 10 needs to be reinforced on this basis.

[0049] In this embodiment, the beam body 10 with the rear opening is reinforced by the reinforcing rib group 20 so that the structural strength of the beam body 10 can meet the requirements of building use.

[0050] The reinforcing rib group 20 is connected to the web 101;

[0051] On one side of the web 101, a reinforcing rib group 20 is disposed between adjacent through holes 11. The structural reinforcement requirements of the beam body 10 can be met by a group of reinforcing rib groups 20.

[0052] Combination Figure 1 As shown, the reinforcing rib group 20 includes a first reinforcing rib 21 and a second reinforcing rib 22 . The first reinforcing rib 21 and the second reinforcing rib 22 are both connected to the web 101 . The material of the first reinforcing rib 21 and the second reinforcing rib 22 is consistent with that of the web 101 .

[0053] The first reinforcing rib 21 and the second reinforcing rib 22 are arranged crosswise. The first reinforcing rib 21 and the second reinforcing rib 22 are both plate structures with equal thickness, and the two are crossed to form an approximate "X" shape. Preferably, the first reinforcing rib 21 and the second reinforcing rib 22 are connected to the web 101 by welding, and specifically, a double-sided fillet weld can be used, and the weld height is greater than or equal to 0.7T, where T is the thickness of the plate structure of the reinforcing rib group 20 (the thickness of the first reinforcing rib 21 or the second reinforcing rib 22). By setting the reinforcing rib group 20 of this structure, the through hole 11 is arranged along the length direction of the beam body 10 ( Figure 1 The two groups of reinforcing ribs 20 on both sides of the first direction a) approximately surround the through hole 11, so that the web 101 located around the through hole 11 can be fully reinforced, thereby ensuring the better structural strength and stiffness of the web 101, so that the overall stiffness of the beam body 10 and the shear stress resistance of the web can still reach a level close to that before the hole is opened.

[0054] In this embodiment, the reinforcing rib group 20 adopts a cross shape similar to an "X" shape to reinforce the structure around the through hole 11. In other alternative embodiments, the reinforcing rib group 20 can be parallel diagonal braces or other structures, and the specific shape of the reinforcing rib group 20 can be adjusted based on actual needs.

[0055] Please continue to refer to Figure 1 and Figure 2 As shown, the intersection position of the first reinforcing rib 21 and the second reinforcing rib 22 is in the height direction of the web 101 ( Figure 2 The center position of the third direction c) has a certain offset relationship, and the specific offset distance can be set based on the actual construction error. In other alternative embodiments, the intersection position of the first reinforcing rib 21 and the second reinforcing rib 22 can coincide with the center position of the web 101 in the height direction.

[0056] Please continue to refer to Figure 1 As shown, one of the first reinforcing rib 21 and the second reinforcing rib 22 is a full-length oblique rib and the other is a segmented oblique rib, wherein the full-length oblique rib is an integrated oblique rib and the segmented oblique rib is a two-segmented oblique rib. The two-segmented oblique ribs are located on both sides of the full-length oblique rib and are non-connected and fitted with the full-length oblique rib, so that the three are combined to form an approximate "X" shape. This shape of reinforcing rib combination can meet the reinforcement requirements of the beam body 10. The two-segmented oblique ribs are non-connected with the full-length oblique ribs, which helps to reduce the workload of on-site construction and improve construction efficiency. The use of full-length oblique ribs helps to ensure the overall consistency of one of the reinforcing ribs, thereby ensuring its superior structural strength and rigidity.

[0057] In other alternative embodiments, the segmented oblique ribs and the full-length oblique ribs may also be connected by welding, and the specific connection method may be adjusted based on the reinforcement requirements of the beam body.

[0058] Please continue to refer to Figure 1 As shown, three through holes 11 are opened on the beam body 10, and the beam body 10 is located in the area outside the through hole 11 at the end side (the beam body 10 Figure 1 There are no holes in the left area of ​​the leftmost through hole and the right area of ​​the rightmost through hole, so the reinforcement requirements here are relatively low. At this time, only one section of the two-section oblique ribs and the full-length oblique ribs can be set outside the through hole at the end of the beam body 10, and the two are T-shaped and cross-enclosed at the end. On the one hand, it can meet the reinforcement of the through hole position at the end, and on the other hand, it helps to realize the standardized setting of the strengthening rib combination.

[0059] In this embodiment, the first reinforcing rib 21 is aligned with the beam body 10 in the length direction ( Figure 1 The angle between the first direction a) and the second reinforcing rib 22 is 45° to 60°, for example, 45°, 50° or 60°. Figure 1 The angle of the first direction a) is 120° to 135°, for example, 120°, 130° or 135°, etc. By limiting the angle, the first reinforcing rib 21 and the second reinforcing rib 22 form a better diagonal bracing effect, thereby improving the overall stability of the beam body 10.

[0060] In this embodiment, the first reinforcing rib 21 and the second reinforcing rib 22 are welded to the web 101. This connection method can form a good reinforcement effect on the weakened structural strength of the web due to the opening. Figure 1 The upper and lower ends of the beam body 10 are naturally fitted with the wing plates 102 (upper wing plates and lower wing plates) of the beam body 10 in a non-connected manner. The first reinforcing ribs 21 and the second reinforcing ribs 22 do not need to be fixedly connected to the wing plates 102 by welding or other connecting methods. Under the premise of ensuring good structural strength of the beam body 10, it helps to reduce the welding workload on site and thus improve construction efficiency.

[0061] Furthermore, the thickness of the first reinforcing rib 21 and the second reinforcing rib 22 is T=t+a;

[0062] The t is equal to the thickness of the web 101 of the beam body 10, and the a is equal to 0-2 mm, for example, a is equal to 0 mm, 1 mm, 1.5 mm or 2 mm. In addition, the width (along the width of the first reinforcing rib 21 and the second reinforcing rib 22) Figure 2 The dimension in the second direction b) is less than or equal to half the width of the wing plate 102 of the beam body 10.

[0063] Combination Figure 2As shown, in this embodiment, the width of the first reinforcing rib 21 and the second reinforcing rib 22 are the same and slightly smaller than half the width of the wing plate 102. At this time, the first reinforcing rib 21 and the second reinforcing rib 22 are both located in the groove of the beam body 10. In other alternative embodiments, the width of the first reinforcing rib 21 and the second reinforcing rib 22 may also be equal to half the width of the wing plate 102.

[0064] By limiting the width of the first reinforcing rib 21 and the second reinforcing rib 22, the first reinforcing rib 21 and the second reinforcing rib 22 are located in the groove of the beam body 10, and do not extend out of the groove of the beam body 10, so that the overall consistency of the beam body 10 can be kept better. At the same time, the thickness of the first reinforcing rib 21 and the second reinforcing rib 22 is limited, so that the first reinforcing rib 21 and the second reinforcing rib 22 under this width can meet the reinforcement requirements of the beam body 10.

[0065] In this embodiment, since the net distance between adjacent through holes 11 is less than H, the diameter of the through hole 11 is limited to be less than or equal to one third of H, where H is the beam height of the beam body 10. This limitation can ensure the rationality of the opening of the through hole 11, that is, the opening will not cause destructive damage to the beam body 10, and the structural rigidity of the beam body 10 and the shear resistance of the web after the opening can be restored to the level before the opening through reinforcement measures.

[0066] In the above embodiment, along the first direction a, the net distance between adjacent through holes 11 is less than H. In other alternative embodiments, the net distance between adjacent through holes 11 may also be less than the diameter of the through hole 11, and the specific structure and distribution of the reinforcing rib group 20 may be adaptively adjusted based on different distribution conditions of the through holes 11.

[0067] In this embodiment, the reinforcing rib group 20 is connected to one side of the web 101 ( Figure 2 The right side of the middle web 101 along the second direction b). The reinforcing rib group 20 of the above structure can meet its reinforcement requirements by being connected to a single side of the web 101.

[0068] In other alternative embodiments, Figure 3 As shown, the reinforcing rib group 20 is connected to both sides of the web 101 ( Figure 3 At this time, the reinforcing rib groups 20 are evenly distributed on both sides of the web 101, that is, between the adjacent through holes 11, there is a group of reinforcing rib groups 20 on both sides of the web 101, so that the overall reinforcement structure of the beam body 10 is a symmetrical distributed structure, so as to further ensure the structural strength of the beam body 10.

[0069] This embodiment also provides a method for manufacturing a small-spacing rear-opening reinforced steel beam, comprising the following steps:

[0070] S1: A through hole 11 is opened in the web 101 of the beam body 10, and a magnetic drill or plasma cutting is used to open the through hole to reduce the degree of damage to the beam structure caused by the opening; along the length direction of the beam body 10 ( Figure 1 In the first direction a), the net distance between adjacent through holes is less than the beam height of the beam body 10;

[0071] S2: Temporarily support the beam body 10, for example, by supporting the beam body with a temporary scaffold or a supporting structure, so as to reduce the direct load borne by the beam body during the opening process and prevent the beam body structure from being damaged and crushed during the opening process.

[0072] S3: Welding the reinforcing rib group 20 to the web 101 of the beam body 10, and providing a reinforcing rib group 20 between adjacent through holes 11 on one side of the web 101, and preferably connecting the reinforcing rib group 20 to both sides of the web 101, so that the beam body 10 forms a symmetrical reinforcement structure on both sides of its width;

[0073] The reinforcing rib group 20 includes a first reinforcing rib 21 and a second reinforcing rib 22. The first reinforcing rib 21 and the second reinforcing rib 22 are plate structures with the same thickness. The first reinforcing rib 21 and the second reinforcing rib 22 are both welded to the web 101. The end of the reinforcing rib group 20 ( Figure 1 The upper and lower ends of the first reinforcing rib 21 and the second reinforcing rib 22 are in a non-connected fit with the flange 102 of the beam body 10. The first reinforcing rib 21 and the second reinforcing rib 22 form an approximately "X"-shaped cross structure. The first reinforcing rib 21 and the second reinforcing rib 22 are connected to the web of the beam body 10 by welding, specifically by double-sided fillet welds, and the weld height is greater than or equal to 0.7T, where T is the thickness of the first reinforcing rib 21 or the second reinforcing rib 22, so as to ensure the local connection strength between the first reinforcing rib 21 and the second reinforcing rib 22 and the web.

[0074] S4: Remove temporary supports.

[0075] Through the above-mentioned production method, a post-opening reinforcement method on the existing steel beam is provided. After adopting the opening and reinforcement method of the present invention, the bearing capacity and stiffness of the steel beam can still meet or be close to the original design requirements, and can effectively solve the actual engineering needs of the post-opening of the steel beam web.

[0076] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0077] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A small-spacing rear-opening reinforced steel beam, characterized in that: include: Beam and stiffener group; The web of the beam body is provided with a plurality of through holes, and each of the through holes is arranged along the length direction of the beam body; Along the length direction of the beam body, the net distance between adjacent through holes is smaller than the beam height of the beam body; The reinforcing rib group is connected to the web; On one side of the web, a reinforcing rib group is arranged between adjacent through holes.

2. The small-pitch rear-opening reinforced steel beam according to claim 1, characterized in that: The reinforcing rib group includes a first reinforcing rib and a second reinforcing rib, the first reinforcing rib and the second reinforcing rib are both connected to the web, and the first reinforcing rib and the second reinforcing rib are cross-arranged.

3. The small-pitch rear-opening reinforced steel beam according to claim 1, characterized in that: The reinforcing rib group is connected to a single side of the web.

4. The small-spacing rear-opening reinforced steel beam according to claim 2, characterized in that: The ends of the first reinforcing rib and the second reinforcing rib are in a non-connected fit with the wing plate of the beam body.

5. The small-spacing rear-opening reinforced steel beam according to claim 2, characterized in that: The thickness of the first reinforcement rib and the second reinforcement rib is T=t+a; The t is equal to the web thickness of the beam body, and the a is equal to 0 to 2 mm.

6. The small-spacing rear-opening reinforced steel beam according to claim 2, characterized in that: The width of the first reinforcing rib and the second reinforcing rib is less than or equal to half of the wing plate width of the beam body.

7. The small-spacing rear-opening reinforced steel beam according to claim 2, characterized in that: Among the first reinforcement rib and the second reinforcement rib, one has an angle of 45° to 60° with the length direction of the beam body, and the other has an angle of 120° to 135° with the length direction of the beam body.

8. The small-spacing rear-opening reinforced steel beam according to claim 1, characterized in that: The diameter of the through hole is less than or equal to one third of H, where H is the beam height of the beam body.

9. A method for manufacturing a small-spacing rear-opening reinforced steel beam, characterized in that: The following steps are involved: Provide temporary support for the beam; Through holes are provided on the web of the beam body, and along the length direction of the beam body, the net distance between adjacent through holes is less than the beam height of the beam body; The reinforcing rib group is welded to the web of the beam body, and one reinforcing rib group is arranged between adjacent through holes on one side of the web; Remove temporary supports.

10. The method for manufacturing a small-pitch rear-opening reinforced steel beam according to claim 9, characterized in that: The through holes are formed by using magnetic drilling or plasma cutting; and / or, the reinforcing rib group is connected to the web of the beam body by welding, using double-sided fillet welds, and the weld height is greater than or equal to 0.7T, where T is the thickness of the reinforcing rib group; and / or, the reinforcing rib group is connected to a single side of the web; And / or, the reinforcing rib group includes a first reinforcing rib and a second reinforcing rib, the first reinforcing rib and the second reinforcing rib are both connected to the web, and the first reinforcing rib and the second reinforcing rib are cross-arranged; one of the first reinforcing rib and the second reinforcing rib is a full-length oblique rib, and the other is a segmented oblique rib, the full-length oblique rib is an integral oblique rib, and the segmented oblique rib is a two-segmented oblique rib, the two-segmented oblique ribs are respectively located on both sides of the full-length oblique rib, and are in a non-connected fit with the full-length oblique rib; And / or, the end portions of the reinforcing rib group are in non-connected contact with the wing plates of the beam body.

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