A replaceable orthotropic steel bridge deck system and method of installation

Abstract

The application discloses a replaceable orthotropic steel bridge deck panel system and a replacement method, and the method comprises the following steps: detachably connecting and fixing the bottom of a plurality of orthotropic steel bridge deck panels with the top of bridge deck cross beams, and connecting two orthotropic steel bridge deck panels adjacent to each other along the cross bridge through splicing connectors; when it is detected that a certain orthotropic steel bridge deck panel has structural abnormalities, the splicing connector on the orthotropic steel bridge deck panel and the orthotropic steel bridge deck panel adjacent to each other in the cross bridge direction is detached, the bottom of the orthotropic steel bridge deck panel and the top of the bridge deck cross beam are detached, and the orthotropic steel bridge deck panel is pulled out in the direction perpendicular to the bridge deck top plate; a new orthotropic steel bridge deck panel is installed at the position of the detached orthotropic steel bridge deck panel, and is fixed with the orthotropic steel bridge deck panel adjacent to each other in the cross bridge direction through the splicing connector; and the bottom of the new orthotropic steel bridge deck panel and the top of the bridge deck cross beam are refixed, so that the replacement of the orthotropic steel bridge deck panel is realized.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology, and more specifically, relates to a system and method for replacing orthotropic steel bridge deck panels that can be partitioned and replaced. Background Technology

[0002] Orthotropic steel bridge decks are load-bearing structures composed of longitudinally and transversely perpendicular stiffening ribs (or diaphragms) and a steel top plate. The self-weight of an orthotropic steel bridge deck is approximately 1 / 4 to 1 / 5 that of a reinforced concrete or precast prestressed concrete bridge deck, and it is convenient to transport and erect, with a short construction period. Proposed in the 1930s, and first applied to the construction of the Kurpfalz Bridge in 1950, this bridge was the world's first steel bridge to use orthotropic steel bridge decks as part of the main girder for load-bearing while simultaneously serving as the bridge deck to bear localized traffic loads. Since then, orthotropic steel bridge decks have been widely used in steel bridge engineering.

[0003] However, the existing orthotropic steel bridge decks have complex structures and numerous welds. Limited manufacturing technology and excessive traffic loads contribute to significant fatigue problems. Studies show that fatigue-prone areas are mainly concentrated in welding details such as the top plate-longitudinal rib weld, the longitudinal rib-transverse diaphragm weld, and the top plate-longitudinal rib-transverse diaphragm weld. For example, some bridges use U-ribs welded to the steel top plate; due to the weld and welding stress, the U-ribs, top steel plate, and the welds connecting them are prone to fatigue cracking. Others weld the sides of the U-ribs to the transverse diaphragms; the transverse diaphragms near the U-ribs and the welds between the U-ribs and transverse diaphragms are also prone to fatigue cracking. After fatigue cracking of the orthotropic steel bridge deck, local reinforcement is required to ensure structural performance and operational quality. However, on-site reinforcement requires demanding conditions, is difficult to implement, expensive, and often fails to achieve satisfactory reinforcement results. Furthermore, reinforcement of orthotropic steel bridge decks may introduce new fatigue defects, posing a risk of further fatigue cracking and increasing the overall life-cycle cost. More seriously, when the orthotropic steel bridge deck is partially damaged and cannot meet the normal use of the bridge, it needs to be demolished and rebuilt. This not only interrupts traffic but also fails to fully utilize the functions of the remaining steel beam components, seriously hindering the high-performance design and sustainable development of bridge engineering.

[0004] Therefore, there is an urgent need for an orthotropic steel bridge deck that can be dismantled in sections and easily replaced as a whole. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for replacing orthotropic steel bridge deck panels in sections. By configuring traditional bridge deck panels into multiple sections of orthotropic steel bridge deck panels that are detachably connected to adjacent orthotropic steel bridge deck panels and bridge deck beams along the transverse direction, bridge deck panels with localized fatigue damage can be easily removed from the bridge deck beams, thereby achieving overall section replacement of orthotropic steel bridge deck panels. This solves the problem in existing technologies where orthotropic steel bridge deck panels are prone to fatigue damage and are difficult to repair after damage.

[0006] To achieve the above objectives, one aspect of the present invention provides a method for installing and replacing orthotropic steel bridge deck panels that can be replaced in sections, comprising the following steps:

[0007] S1: The bottom of multiple orthotropic steel bridge deck panels is detachably connected and fixed to the top of the bridge deck crossbeam. Two adjacent orthotropic steel bridge deck panels along the crossbeam are connected by splicing connectors to complete the installation of the orthotropic steel bridge deck panels and the bridge deck crossbeam.

[0008] S2: When a structural abnormality is detected in a certain orthotropic steel bridge deck, the splicing connector on the orthotropic steel bridge deck and the orthotropic steel bridge deck adjacent in the transverse direction is disassembled, the bottom of the orthotropic steel bridge deck is disassembled from the top of the bridge deck beam, and the orthotropic steel bridge deck is pulled out in a direction perpendicular to the top plate of the bridge deck.

[0009] S3: Install the new orthotropic steel bridge deck as a replacement onto the location of the orthotropic steel bridge deck that was removed in step S2, and fix it to the orthotropic steel bridge deck adjacent to the transverse bridge upwards through splicing connectors.

[0010] S4: Re-fix the bottom of the new orthotropic steel bridge deck to the top of the bridge deck beam to complete the sectional replacement of the orthotropic steel bridge deck.

[0011] Another aspect of the present invention provides a system for replacing orthotropic steel bridge deck panels in sections, for implementing the aforementioned method for installing and replacing orthotropic steel bridge deck panels in sections. The system includes multiple bridge deck beams arranged parallel and spaced along the longitudinal direction of the bridge, multiple orthotropic steel bridge deck panels detachably installed on the multiple bridge deck beams along the transverse direction of the bridge, and splicing connectors detachably connecting adjacent orthotropic steel bridge deck panels along the transverse direction of the bridge. By configuring the multiple orthotropic steel bridge deck panels to be sequentially detachably connected along the transverse direction and detachably connected to the bridge deck beams, bridge deck panels with localized fatigue damage can be easily removed, thereby achieving the section replacement of orthotropic steel bridge deck panels.

[0012] Furthermore, the orthotropic steel bridge deck includes a bridge deck top plate, a plurality of U-rib plates and a plurality of transverse diaphragms arranged at the bottom of the bridge deck top plate.

[0013] Furthermore, the splicing connector includes a first splicing plate and a second splicing plate; the first splicing plate is used to connect two adjacent bridge deck top plates arranged along the transverse direction of the bridge; the second splicing plate is used to connect two adjacent transverse diaphragms arranged along the transverse direction of the bridge.

[0014] Furthermore, the longitudinal central axis of the diaphragm is aligned with the longitudinal central axis of the bridge deck beam; the U-rib is perpendicular to the longitudinal central axis of the diaphragm.

[0015] Furthermore, the bridge deck crossbeam includes a crossbeam partition, a first flange plate installed at the top and bottom of the crossbeam partition, and a plurality of crossbeam stiffening plates disposed on the side of the crossbeam partition.

[0016] Furthermore, the two first flange plates are parallel to each other and perpendicular to the crossbeam partition;

[0017] Multiple crossbeam stiffening plates are arranged vertically in parallel at intervals.

[0018] Furthermore, the upper and lower ends of the stiffening plate of the crossbeam are fixed to the first flange plates at the top and bottom of the crossbeam partition, respectively.

[0019] Furthermore, the bottom of the diaphragm is provided with a second flange plate parallel to the top plate of the bridge deck.

[0020] Furthermore, the top of the diaphragm and the bridge deck top plate are fixed, while the second flange plate at the bottom of the diaphragm and the first flange plate at the top of the bridge deck beam are detachably fixed.

[0021] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0022] 1. The present invention provides a system and method for replacing orthotropic steel bridge deck panels in sections. By configuring the traditional bridge deck panels into multiple sections of orthotropic steel bridge deck panels that are detachably connected to adjacent orthotropic steel bridge deck panels and bridge deck crossbeams along the transverse direction, the bridge deck panels with local fatigue damage can be easily removed from the bridge deck crossbeams, thereby achieving overall section replacement of the orthotropic steel bridge deck panels. This solves the problem in the prior art that orthotropic steel bridge deck panels are prone to fatigue damage and are difficult to repair after damage.

[0023] 2. The present invention provides a sectional replacement system for orthotropic steel bridge decks, wherein the orthotropic steel bridge decks are configured to rely solely on splicing plates, bolts, and flange plates as detachable connecting components, without any fixed connection to other components. This allows for easy removal of the bridge decks corresponding to fatigue damage zones, enabling overall replacement. The orthotropic steel bridge decks, splicing connectors, and flange plates on the bridge deck crossbeams are all detachable structures, capable of being manufactured as standardized components, facilitating production, installation, and replacement.

[0024] 3. The present invention provides a partitioned replaceable orthotropic steel bridge deck system and installation and replacement method, which allows for easy removal of damaged bridge decks by laterally disassembling the bolts on the splicing plates and flange plates. During secondary maintenance on site, the detachable bolts used for connection can be reused, which can improve the service life of each structure and save costs.

[0025] 4. The present invention provides a partitioned replaceable orthotropic steel bridge deck system and installation and replacement method, which is applicable to suspension bridge technology and requires that the stress level in the completed bridge stage be low before replacement can be carried out. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the working state of a partition-replaceable orthotropic steel bridge deck system according to an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the overall structure of a partition-replaceable orthotropic steel bridge deck system according to an embodiment of the present invention;

[0028] Figure 3 This is a structural schematic diagram (transverse bridge view) of a splicing connector of a modularly replaceable orthotropic steel bridge deck system according to an embodiment of the present invention.

[0029] Figure 4 This is a structural schematic diagram (longitudinal bridge view) of a splicing connector of a replaceable orthotropic steel bridge deck system according to an embodiment of the present invention.

[0030] Figure 5 This is a schematic flowchart illustrating an installation and replacement method for a modularly replaceable orthotropic steel bridge deck according to an embodiment of the present invention.

[0031] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-bridge deck crossbeam, 11-crossbeam diaphragm, 12-first flange plate, 13-crossbeam stiffening plate, 2-orthotropic steel bridge deck, 21-bridge deck top plate, 22-U-rib plate, 23-diaphragm, 231-second flange plate, 3-jointing connector, 31-first splice plate, 32-second splice plate, 4-bolt. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, when an element is referred to as "fixed to," "set on," or "provided on" another element, it can be directly on or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to or indirectly connected to the other element. The terms "mounted," "connected," "linked," and "provided with" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0035] like Figures 1-4As shown, one aspect of the present invention provides a system for replacing orthotropic steel bridge deck panels in sections, comprising a plurality of bridge deck beams 1 arranged parallel and spaced along the longitudinal direction of the bridge, a plurality of orthotropic steel bridge deck panels 2 detachably installed on the plurality of bridge deck beams 1 along the transverse direction of the bridge, and splicing connectors 3 detachably connecting adjacent orthotropic steel bridge deck panels 2 along the transverse direction of the bridge; the orthotropic steel bridge deck panels 2 include a bridge deck top plate 21, a plurality of U-rib plates 22 and a plurality of transverse diaphragms 23 arranged at the bottom of the bridge deck top plate 21; the longitudinal central axis of the transverse diaphragms 23 is aligned with the longitudinal central axis of the bridge deck beams 1; the splicing connectors 3 include a first splicing plate 31 and a second splicing plate 32; the first splicing plate 31... 1. A second splicing plate 32 is used to connect two adjacent bridge deck top plates 21 arranged along the transverse direction; the second splicing plate 32 is used to connect two adjacent transverse diaphragms 23 arranged along the transverse direction; the first splicing plate 31 is connected to the two adjacent bridge deck top plates 21 arranged along the transverse direction by bolts 4; the second splicing plate 32 is connected to the two adjacent transverse diaphragms 23 arranged along the transverse direction by bolts 4; the present invention sets the traditional bridge deck as multiple partitioned orthotropic steel bridge decks that are detachably connected to adjacent orthotropic steel bridge decks and bridge deck crossbeams along the transverse direction, so that bridge decks with local fatigue damage can be easily removed from the bridge deck crossbeams, thereby realizing the overall partitioned replacement of orthotropic steel bridge decks.

[0036] Furthermore, such as Figures 1-4 As shown, multiple U-ribs 22 are arranged parallel to each other at intervals at the bottom of the bridge deck top plate 21; multiple transverse diaphragms 23 are arranged parallel to each other at intervals at the bottom of the bridge deck top plate 21; the longitudinal central axis of the U-ribs 22 and the transverse diaphragms 23 are perpendicular; the top of the transverse diaphragms 23 is provided with a U-shaped mounting groove that matches the shape and number of the U-ribs 22; the U-ribs 22 are installed in the U-shaped mounting groove; the bottom of the transverse diaphragms 23 is provided with a second flange plate 231 that is parallel to the bridge deck top plate 21, and the second flange plate 231 is fixed to the bridge deck crossbeam 1.

[0037] Furthermore, such as Figures 1-4 As shown, the bridge deck crossbeam 1 includes a crossbeam partition 11, first flange plates 12 installed on the top and bottom of the crossbeam partition 11, and a plurality of crossbeam stiffening plates 13 disposed on the side of the crossbeam partition 11; the two first flange plates 12 are parallel to each other and perpendicular to the crossbeam partition 11; the plurality of crossbeam stiffening plates 13 are arranged vertically in parallel intervals; the upper and lower ends of the crossbeam stiffening plates 13 are respectively fixed to the first flange plates 12 at the top and bottom of the crossbeam partition 11.

[0038] Furthermore, such as Figures 1-4As shown, the top of the diaphragm 23 is fixed to the bridge deck top plate 21, and the second flange plate 231 at the bottom of the diaphragm 23 and the first flange plate 12 at the top of the bridge deck beam 1 are detachably fixed, such as by bolts.

[0039] Furthermore, such as Figure 5 As shown, another aspect of the present invention provides a method for installing and replacing orthotropic steel bridge deck panels that can be replaced in sections, suitable for suspension bridges where the stress level is relatively low during the bridge completion stage. This method is implemented using the aforementioned section-based, integrally replaceable orthotropic steel bridge deck panel system and includes the following steps:

[0040] S1: The bottom of multiple orthotropic steel bridge deck panels 2 are detachably connected and fixed to the top of the bridge deck crossbeam 1. Two adjacent orthotropic steel bridge deck panels 2 along the crossbeam are connected by splicing connectors 3 to complete the installation of the orthotropic steel bridge deck panels 2 and the bridge deck crossbeam 1.

[0041] S2: When a structural abnormality is detected in a certain orthotropic steel bridge deck 2, the splicing connector 3 on the orthotropic steel bridge deck 2 and the orthotropic steel bridge deck adjacent in the transverse direction is disassembled, the bottom of the orthotropic steel bridge deck 2 is disassembled from the top of the bridge deck beam 1, and the orthotropic steel bridge deck 2 is pulled out in a direction perpendicular to the top plate 21 of the bridge deck.

[0042] S3: Install the new orthotropic steel bridge deck as a replacement onto the location of the orthotropic steel bridge deck 2 that was removed in step S2, and fix the new orthotropic steel bridge deck to the orthotropic steel bridge deck adjacent to the transverse bridge in the upward direction using the splicing connector 3.

[0043] S4: Re-fix the bottom of the new orthotropic steel bridge deck to the top of the bridge deck beam 1 to complete the partition replacement of the orthotropic steel bridge deck.

[0044] Furthermore, in an embodiment of the present invention, step S1 involves detachably connecting and fixing the bottom of multiple orthotropic steel bridge deck panels 2 to the top of the bridge deck crossbeam 1, and connecting two adjacent orthotropic steel bridge deck panels 2 along the crossbeam using splicing connectors 3, including the following steps:

[0045] S11: Place multiple orthotropic steel bridge deck panels 2 sequentially on the bridge deck beams 1 along the transverse direction, such that the second flange plate 231 at the bottom of each diaphragm 23 is placed on the corresponding first flange plate 12 at the top of each bridge deck beam 1, and fix it.

[0046] S12: Fix two adjacent orthotropic steel bridge deck panels 2 using splicing connectors 3; specifically, the first splicing plate 31 of the splicing connector 3 is detachably connected to two adjacent bridge deck top plates 21, and the second splicing plate 32 of the splicing connector 3 is detachably connected to two adjacent transverse diaphragms 23 arranged along the transverse direction of the bridge, thus completing the installation of the orthotropic steel bridge deck panels 2; the detachable connection here can be a bolt connection or other detachable connection methods.

[0047] Further, in an embodiment of the present invention, step S2, disassembling the orthotropic steel bridge deck 2 and the splicing connector 3 on the orthotropic steel bridge deck adjacent in the transverse direction includes disassembling the bolts between the bridge deck top plate 21 of the orthotropic steel bridge deck 2 and the first splicing plate 31 thereon, and disassembling the bolts between the transverse diaphragm 23 of the orthotropic steel bridge deck 2 and the second splicing plate 32 thereon; step S2, disassembling the bottom of the orthotropic steel bridge deck 2 and the top of the bridge deck crossbeam 1 includes disassembling the bolts between the second flange plate 231 at the bottom of the transverse diaphragm 23 of the orthotropic steel bridge deck 2 and the first flange plate 12 at the top of the bridge deck crossbeam 1.

[0048] Furthermore, in an embodiment of the present invention, step S3, which involves fixing the new orthotropic steel bridge deck to the orthotropic steel bridge deck adjacent to it in the transverse direction using the splicing connector 3, includes: detachably connecting the first splicing plate 31 of the splicing connector 3 to two adjacent bridge deck top plates 21, and detachably connecting the second splicing plate 32 of the splicing connector 3 to two adjacent transverse diaphragms 23 arranged in the transverse direction of the bridge, thereby completing the installation of the new orthotropic steel bridge deck.

[0049] Furthermore, in an embodiment of the present invention, step S4, which involves re-fixing the bottom of the new orthotropic steel bridge deck to the top of the bridge deck beam 1, includes fixing the second flange plate 231 at the bottom of the transverse diaphragm of the new orthotropic steel bridge deck to the first flange plate 12 at the top of the bridge deck beam 1.

[0050] This invention provides a system and method for replacing orthotropic steel bridge deck panels in sections. By configuring traditional bridge deck panels into multiple sections of orthotropic steel bridge deck panels that are detachably connected to adjacent orthotropic steel bridge deck panels and bridge deck beams along the transverse direction, bridge deck panels with local fatigue damage can be easily removed from the bridge deck beams, thereby achieving overall section replacement of orthotropic steel bridge deck panels. This solves the problem in the prior art that orthotropic steel bridge deck panels are prone to fatigue damage and are difficult to repair after damage.

[0051] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for installing and replacing orthotropic steel bridge deck panels that can be replaced in sections, characterized in that, This is achieved using a zone-replaceable orthotropic steel bridge deck system, including the following steps: S1: The second flange plate (231) at the bottom of the transverse diaphragm (23) of multiple orthotropic steel bridge decks (2) is detachably connected and fixed to the first flange plate (12) at the top of the bridge deck beams (1) arranged parallel to each other along the longitudinal direction. The two adjacent orthotropic steel bridge decks (2) along the transverse direction are detachably spliced ​​with the bridge deck top plate (21) and the transverse diaphragm (23) through the splicing connector (3), thus completing the installation of the orthotropic steel bridge deck (2) and the bridge deck beams (1). The splicing connector (3) includes a first splicing plate (31) and a second splicing plate (32). The first splicing plate (31) is used to connect two adjacent bridge deck top plates (21) arranged along the transverse direction. The second splicing plate (32) is used to connect two adjacent transverse diaphragms (23) arranged along the transverse direction. S2: When a structural abnormality is detected in a certain orthotropic steel bridge deck (2), the first splicing plate (31) and the second splicing plate (32) between the structurally abnormal orthotropic steel bridge deck (2) and the orthotropic steel bridge deck adjacent in the transverse direction are disassembled, the second flange plate (231) at the bottom of the transverse diaphragm (23) of the structurally abnormal orthotropic steel bridge deck (2) and the first flange plate (12) at the top of the bridge deck beam (1) are disassembled, and the structurally abnormal orthotropic steel bridge deck (2) is pulled out in a direction perpendicular to the top plate (21) of the bridge deck. S3: The new orthotropic steel bridge deck, which is to be used as a replacement, is installed at the location of the orthotropic steel bridge deck (2) that was removed in step S2. It is fixed to the bridge deck top plate (21) of the orthotropic steel bridge deck adjacent to the transverse bridge in the upward direction by the first splicing plate (31), and fixed to the transverse diaphragm (23) of the orthotropic steel bridge deck adjacent to the transverse bridge in the upward direction by the second splicing plate (32). S4: The second flange plate (231) at the bottom of the transverse diaphragm (23) of the new orthotropic steel bridge deck (2) is re-detachably fixed to the first flange plate (12) at the top of the bridge deck beam (1), thus completing the partition replacement of the orthotropic steel bridge deck. The replaceable orthotropic steel bridge deck system includes multiple bridge deck beams (1) arranged parallel to each other along the longitudinal direction, multiple orthotropic steel bridge decks (2) detachably installed on the multiple bridge deck beams (1) along the transverse direction, and splicing connectors (3) detachably connecting two adjacent orthotropic steel bridge decks (2) along the transverse direction. By setting the multiple orthotropic steel bridge decks to be detachably connected sequentially along the transverse direction and detachably connected to the bridge deck beams, bridge decks with local fatigue damage can be easily removed, thereby realizing the sectional replacement of orthotropic steel bridge decks. The orthotropic steel bridge deck (2) includes a bridge deck top plate (21), a plurality of U-rib plates (22) and a plurality of transverse diaphragms (23) arranged at the bottom of the bridge deck top plate (21). The bridge deck crossbeam (1) includes a crossbeam partition (11) and a first flange plate (12) installed on the top and bottom of the crossbeam partition (11). The bottom of the diaphragm (23) is provided with a second flange plate (231) parallel to the top plate of the bridge deck (21).

2. A system for replacing orthotropic steel bridge deck panels in sections, characterized in that, To implement the installation and replacement method for the orthotropic steel bridge deck that can be replaced in sections as described in claim 1, the longitudinal center axis of the diaphragm (23) is aligned with the longitudinal center axis of the bridge deck beam (1); the U-rib plate (22) is perpendicular to the longitudinal center axis of the diaphragm (23).

3. A system for replacing orthotropic steel bridge deck panels in sections according to claim 2, characterized in that: The bridge deck crossbeam (1) also includes a plurality of crossbeam stiffening plates (13) disposed on the side of the crossbeam partition (11).

4. A system for replacing orthotropic steel bridge deck panels in sections according to claim 3, characterized in that: The two first flanges (12) are parallel to each other and perpendicular to the crossbeam partition (11); Multiple crossbeam stiffening plates (13) are arranged vertically in parallel intervals.

5. A system for replacing orthotropic steel bridge deck panels in sections according to claim 4, characterized in that: The upper and lower ends of the crossbeam stiffening plate (13) are respectively fixed to the first flange plate (12) at the top and bottom of the crossbeam partition (11).

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