Gantry crane girder structure and reinforcing method thereof

Abstract

A gantry crane main beam structure and a method for strengthening the main beam structure are disclosed. The main beam body includes a top and a bottom extending parallel to each other, and has a lifting contact area that contacts the lifting device during transport. In the lifting contact area, multiple reinforcing plates and multiple stiffening ribs are fixedly installed inside the main beam body. The reinforcing plates are arranged longitudinally parallel to each other and extend parallel to the top and bottom, while the stiffening ribs penetrate the reinforcing plates vertically and support them. The reinforcing plates distribute the concentrated lifting load horizontally, and the stiffening ribs constrain the out-of-plane deformation of the reinforcing plates, preventing local buckling and weld cracking of the main beam body under lifting conditions.

Description

Technical Field

[0001] This invention relates to the field of structural design technology for lifting equipment, specifically to a main beam structure for a gantry crane and a method for strengthening it. Background Technology

[0002] In the sea loading and lashing operations of ultra-large gantry cranes, the main beam is the core load-bearing component of the equipment, and its structural strength directly determines the safety of the loading operation and the stability of the sea transport process. During the sea loading process, self-propelled modular transporters (SPMTs) are typically used to lift the tower and raise the entire gantry crane to the loading height, with the contact area between the tower and the main beam bearing the concentrated lifting load. During the sea lashing process, the restraining force of the lashing ropes acts directly on the pre-set lashing points of the main beam, and the periodic dynamic loads generated by wind and waves during sea navigation exert a continuous impact on the main beam. The load characteristics of these two working conditions are fundamentally different from those of the daily lifting operations of gantry cranes.

[0003] Existing ultra-large gantry cranes typically employ box-shaped or truss-type cross-section structures for their main beams. Their design is based on routine lifting operations, with loads distributed along the beam's span. The main beam primarily experiences overall bending stress. The cross-sectional dimensions and weld specifications of the main load-bearing components are determined according to the overall bending stress level. Local reinforcement is usually only applied to the trolley track support area and the end connection areas of the main beam. During the sea transport and lashing operations, when the aforementioned conventional main beam structure is subjected to loads not designed for these conditions, the industry typically employs temporary support fixtures as a remedial measure. This involves adding temporary support structures during the transportation phase to assist the main beam in bearing the load, and then removing the temporary fixtures after transportation is completed.

[0004] However, when the SPMT tower lifts the gantry crane and applies a concentrated load vertically to the contact area between the main beam and the SPMT tower, the load transfer path changes. The concentrated load acts directly on a localized area of ​​the main beam's primary load-bearing components, subjecting them to out-of-plane bending. The cross-sectional thickness of the primary load-bearing components is insufficient to resist this out-of-plane bending stress, leading to localized out-of-plane buckling. Simultaneously, the welds near the concentrated load application point experience tearing stress, with the stress concentration factor far exceeding the weld design margin, causing weld cracking. Furthermore, the restraining force of the lashing ropes acts as a concentrated force at the root of the main beam's lashing structure. The six-degree-of-freedom motion at sea causes the lashing force to fluctuate at a low frequency periodically, and the geometric discontinuities in the lashing point area become fatigue crack initiation points. During the sea voyage of several days to several weeks, the local stress amplitude at the lashing point can easily exceed the material's fatigue limit, leading to rapid initiation and propagation of fatigue cracks, ultimately causing structural failure at the lashing point and loosening of the lashing. While temporary support fixtures are feasible in engineering, they require additional design, manufacturing, installation, and dismantling, increasing operating costs and time, and cannot solve the fundamental problem of insufficient load-bearing capacity at the main beam structural level.

[0005] Therefore, how to provide a gantry crane main beam structure that can simultaneously meet the requirements of resisting local buckling and weld cracking caused by concentrated loads under the lifting and loading conditions, and resisting fatigue failure of the binding points caused by periodic dynamic loads under the sea lashing conditions, without the need to add temporary support fixtures, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to address the problem of insufficient structural strength of the main beam of ultra-large gantry cranes in the prior art under SPMT lifting and loading conditions and marine lashing conditions, and to provide a gantry crane main beam structure and a method for strengthening the main beam structure, so that the main beam can simultaneously meet the load-bearing requirements of resisting concentrated loads under lifting and loading conditions and resisting periodic dynamic loads under marine lashing conditions.

[0007] According to the present invention, a gantry crane main beam structure is provided, including a main beam body, the main beam body including a top and a bottom extending parallel to each other, and having a lifting contact area that contacts a lifting device in the transport state. In the lifting contact area, a plurality of reinforcing plates and a plurality of stiffening ribs are fixedly arranged inside the main beam body. The plurality of reinforcing plates are arranged longitudinally parallel to each other, each reinforcing plate extending parallel to the top and bottom of the main beam body, and the plurality of stiffening ribs perpendicularly penetrate the plurality of reinforcing plates to support the plurality of reinforcing plates.

[0008] With the above structure, the stiffening plate distributes the concentrated lifting load horizontally to a larger area of ​​the main beam body, while the stiffening ribs constrain the out-of-plane deformation of the stiffening plate in the vertical direction, preventing the stiffening plate itself from buckling locally. The two work together to achieve local load-bearing strengthening of the main beam body under lifting conditions, avoiding local out-of-plane buckling of the web and weld cracking.

[0009] The main beam also includes paired side sections and an inner frame. The paired side sections are connected between the top and bottom, and the three together form the inner cavity of the main beam. The inner frame is set in the inner cavity of the main beam and fixed to the top, bottom, and paired side sections. This allows the paired side sections and the inner frame to form a double-layer structure inside and outside the inner cavity of the main beam, thereby strengthening the structural strength of the main beam.

[0010] According to another aspect of the invention, a plurality of reinforcing plates are disposed in the lower region of the main beam cavity, each reinforcing plate traversing the inner frame and fixed at both ends to a pair of sides. This allows the reinforcing plates to span the full width of the main beam body section, distributing concentrated loads horizontally across the full width of both sides of the inner frame, thus avoiding load concentration on one side.

[0011] Preferably, each reinforcing plate has a through hole for the stiffening rib to pass through.

[0012] According to another aspect of the invention, a plurality of stiffening ribs are disposed between the inner frame and the paired sides, and each stiffening rib extends upward from the bottom. Preferably, the stiffening ribs are composed of T-shaped profiles, L-shaped profiles, or rectangular cross-section profiles, etc. This allows different cross-sectional shapes to adapt to different load sizes and stiffening plate spacing requirements, improving the flexibility of the reinforcement design.

[0013] According to another aspect of the invention, the gantry crane main beam structure further includes a support truss, which is disposed within the inner cavity of the main beam and fixed to the inner frame. This allows the support truss to enhance the overall rigidity and deformation resistance of the main beam, ensuring uniform stress distribution throughout the entire process of lifting, binding, and sea transport.

[0014] Preferably, the supporting truss is located in the upper region of the main beam cavity and within the inner frame. The supporting truss is a triangular truss, with its three vertices fixed to the inner frame respectively.

[0015] According to another aspect of the invention, the main beam body also has a binding point area for connecting the binding device, in which a binding structure is fixed. This allows the binding structure to provide a reliable connection interface for the binding device, transmitting the binding force to the structural stress-bearing parts of the main beam body, adapting to the load requirements under marine binding conditions.

[0016] This invention also proposes a method for strengthening the main beam structure of a gantry crane, comprising: providing a main beam body; determining the lifting contact area where the main beam body contacts the lifting device in the transportation state; and fixing multiple reinforcing plates and multiple stiffening ribs inside the main beam body within the lifting contact area. Through this method, targeted strengthening of the main beam structure can be achieved, enabling the main beam body to resist concentrated loads, at least in the lifting contact area.

[0017] Preferably, the stress distribution in the lifting contact area is calculated using finite element analysis to obtain the load, force direction distribution, and stress distribution, and based on this, the number and distribution range of reinforcing plates in the lifting contact area are determined. This allows the number and distribution range of reinforcing plates to be targeted and adaptable to the working conditions, reducing the spacing in areas with high stress concentration and increasing the spacing in areas with gentler stress gradients.

[0018] By utilizing the gantry crane main beam structure and reinforcement method of this invention, the local load-bearing capacity of the main beam under jacking conditions is enhanced through the cross-grid structure of reinforcing plates and stiffening ribs. The overall rigidity of the main beam is improved through the support truss, and the binding structural components are adapted to the load requirements under the tying conditions of sea transport. Thus, without the need to add temporary support fixtures, it simultaneously meets the requirements of resisting local buckling and weld cracking caused by concentrated loads under jacking and loading conditions, as well as the requirements of resisting periodic dynamic loads under the tying conditions of sea transport. This simplifies the operation process, reduces operating costs, and can flexibly adapt to the whole machine transportation needs of ultra-large gantry cranes of different specifications. Attached Figure Description

[0019] To gain a more complete understanding of this disclosure, reference can be made to the following description of exemplary embodiments taken in conjunction with the accompanying drawings. The drawings are not intended to limit this disclosure to the specific embodiments depicted therein, and are not necessarily to scale. In the drawings: Figure 1 This is a cross-sectional view of the main beam structure of a gantry crane according to an embodiment of the present invention.

[0020] List of reference numerals

[0021] 1. Main beam body

[0022] 11 Top

[0023] 12 Bottom

[0024] 13 Side

[0025] 14. Inner Frame

[0026] 2 Reinforcing Plates

[0027] 3. Stiffening Ribs

[0028] 4 Support Trusses Detailed Implementation

[0029] The following description of specific embodiments of the invention refers to the accompanying drawings, which illustrate particular embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice it. Other embodiments may be utilized and changes may be made without departing from the scope of the invention. Therefore, the following description of specific embodiments should not be considered limiting. The scope of the invention is defined only by the appended claims and the full scope of their equivalents. The same reference numerals are used throughout the drawings and specific embodiments to refer to the same or similar parts.

[0030] Although the following description uses the ocean loading and lashing operation of an ultra-large gantry crane as an application scenario to illustrate the gantry crane main beam structure and its reinforcement method of the present invention, the main beam structure reinforcement design based on the present invention can also be applied to other large lifting equipment transportation conditions with similar load characteristics, as long as it is necessary to ensure the structural stability of the main beam under the simultaneous action of concentrated jacking load and periodic lashing dynamic load in these devices.

[0031] In this article, directional terms such as "high," "low," "up," and "down" are used relative to the working position of the main beam body 1 (e.g., Figure 1 The positioning shown indicates that "longitudinal" refers to the height direction of the main beam body 1. Figure 1 The directions shown are vertical (up and down) and horizontal (lateral) (referring to the width of the main beam body 1). These directional terms are for illustrative purposes and should not be considered restrictive.

[0032] Figure 1 A cross-section of a gantry crane main beam structure according to an embodiment of the present invention is shown. The main beam body 1 is the load-bearing main body of the gantry crane structure, and it generally extends in the horizontal direction. The main beam body 1 includes a top 11 and a bottom 12 that are opposite to each other and extend parallel to each other. The specific forms of the top 11 and the bottom 12 are not limited, for example, they can be plate-like members, truss chords, or combinations thereof, as long as they extend parallel to each other to form the outer contour reference of the main beam body 1. In this embodiment, the width of the top 11 in the horizontal direction is greater than the width of the bottom 12 in the horizontal direction, so that the cross-section of the main beam body 1 is an inverted trapezoid. This cross-sectional shape allows the top of the main beam body 1 to accommodate equipment such as trolley tracks and running mechanisms, while the bottom width is narrowed to reduce its own weight. However, this is not limiting; the cross-section of the main beam body 1 can also be rectangular, trapezoidal, or other shapes.

[0033] The main beam body 1 also includes a pair of side portions 13. These side portions 13 connect the top 11 and the bottom 12, located on both sides of the cross-section of the main beam body 1, and together with the top 11 and bottom 12, form the inner cavity of the main beam. The cross-sectional shape of the side portions 13 is not limited; for example, they can be plate-like members, rod-like members, or truss-like members, as long as they can connect the top 11 and bottom 12 as a whole and provide sufficient lateral stiffness. An inner frame 14 is provided within the inner cavity of the main beam. The inner frame 14 is fixedly connected between the top 11, bottom 12, and the pair of side portions 13, forming a second layer of load-bearing structure inside the main beam body 1. The cross-section of the inner frame 14 is an inverted trapezoid, with its bottom end directly fixed to the bottom 12 of the main beam body 1, while its top end is spaced a certain distance from the top 11 of the main beam body 1 and fixed to the top 11 and side portions 13 of the main beam body 1 using additional connectors. The inner frame 14 divides the main beam cavity into an internal space and a space between the inner frame 14 and the paired side portions 13. The fixing connection method between the inner frame 14 and the components of the main beam body 1 is not limited; for example, welding, bolting, or riveting can be used. Preferably, the inner frame 14 is welded to the components of the main beam body 1. The specific structural form of the inner frame 14 is also not limited; for example, it can be a frame structure welded from members, or a box-shaped frame bent from plates. The cross-sectional dimensions of its members or plates can be designed according to the overall dimensions and load requirements of the main beam body 1.

[0034] The main girder body 1 has a lifting contact area that comes into contact with a lifting device such as an SPMT lifting tower during transport. The lifting contact area is a localized region on the main girder body 1 that bears the concentrated lifting load transmitted by the SPMT lifting tower; its location is determined by the physical contact relationship between the main girder body 1 and the lifting device. Within the lifting contact area, the main girder body 1 bears the concentrated lifting load and requires targeted structural reinforcement. Similarly, under marine lashing conditions, the main girder body 1 also has lashing point areas for connecting lashing devices, as well as key stress-bearing areas such as the mid-span and end areas where stress concentrates under overall bending. The load magnitude, force direction, and stress distribution in these areas vary and need to be clarified through stress analysis to determine the appropriate reinforcement structure for each area. In this embodiment, finite element analysis is used for stress analysis, and a targeted reinforcement structure including stiffening plates 2, stiffening ribs 3, supporting trusses 4, and lashing structural members is designed.

[0035] In the lifting contact area, multiple reinforcing plates 2 and multiple stiffening ribs 3 are fixedly installed inside the main beam body 1. The multiple reinforcing plates 2 extend parallel to the top 11 and bottom 12 of the main beam body 1 and are arranged longitudinally parallel to each other, that is, arranged at predetermined intervals along the height direction of the main beam body 1. The reinforcing plates 2 are used to distribute concentrated loads horizontally to a larger area of ​​the main beam body 1.

[0036] Preferably, multiple reinforcing plates 2 are disposed in the lower region of the main beam's inner cavity, each reinforcing plate 2 traversing the inner frame 14 and fixed at both ends to paired side portions 13. This arrangement allows the reinforcing plates 2 to span the full width of the main beam body 1's cross-section. When a concentrated lifting load is transmitted to the main beam body 1 through the paired side portions 13, the laterally extending reinforcing plates 2 distribute the concentrated load horizontally across the full width of both sides of the inner frame 14, preventing load concentration on one side. The fixing method between the reinforcing plates 2 and the inner frame 14 and paired side portions 13 is not limited, but welding is preferred, such as double-sided full welding, followed by non-destructive testing to ensure weld quality. However, this is not a necessary choice for achieving load distribution; bolted connections or other mechanical connection methods can also be used.

[0037] The thickness of the reinforcing plate 2 is preferably 1.2 to 3 times the cross-sectional thickness of the main load-bearing component of the main beam body 1. 1.2 times is the minimum effective reinforcement ratio; below this ratio, the reinforcement effect is not significant. 3 times is the upper limit for self-weight control; exceeding this ratio will adversely affect the overall load of the main beam body 1 due to the weight of the reinforcing plate 2 itself. However, this is not a limitation, and the thickness of the reinforcing plate 2 can be adjusted according to specific load conditions.

[0038] The number and distribution range of reinforcing plates 2 are determined based on the stress analysis results of the lifting contact area. Specifically, finite element analysis is used to calculate the stress in the lifting contact area, obtaining the load magnitude, force direction distribution, and stress distribution in this area, and based on this, the number and distribution range of reinforcing plates 2 in the lifting contact area are determined. In areas with high stress concentration, the spacing of reinforcing plates 2 can be reduced; in areas with gentler stress gradients, the spacing can be increased. Similarly, finite element analysis can also be used to calculate the stress in key stress-bearing areas such as the binding point area, mid-span area, and end area, obtaining the load magnitude, force direction distribution, and stress distribution in each area, and based on this, the installation scheme of reinforcing components in each area is determined, including the number and distribution range of reinforcing plates 2, as well as the local increase in cross-sectional thickness, thus making the reinforcement design targeted and adaptable to the working conditions.

[0039] Multiple stiffening ribs 3 extend perpendicularly to and pass through multiple reinforcing plates 2, supporting these reinforcing plates 2. Preferably, the multiple stiffening ribs 3 are arranged between the inner frame 14 and the paired side portions 13, and each stiffening rib 3 extends upward from the bottom 12. In this way, each stiffening rib 3 is directly located on the force transmission path between the side portion 13 and the inner frame 14. When a concentrated load is transmitted through the bottom 12 and the side portion 13, the stiffening rib 3 participates in the vertical force transmission, guiding part of the load to the inner frame 14 and each reinforcing plate 2, reducing the local bearing pressure on the bottom 12.

[0040] Each reinforcing plate 2 has a through hole through which a stiffening rib 3 passes. The stiffening rib 3 passes through the through hole and is fixedly connected to the reinforcing plate 2 at the edge of the through hole. An assembly gap, such as 1mm to 3mm, is typically left between the through hole and the stiffening rib 3, and the hole edge is welded using fillet welds. The horizontally extending reinforcing plates 2 and the vertically extending stiffening ribs 3 form multiple intersecting force transmission nodes. In this way, the reinforcing plates 2 disperse the concentrated load horizontally, and the stiffening ribs 3 transfer the load to all reinforcing plates 2 through vertical connections, forming a multi-directional load transmission path, which significantly helps to disperse the jacking load.

[0041] The cross-sectional shape of the stiffening rib 3 is not limited. In one embodiment of the invention, the stiffening rib 3 is made of a T-shaped profile, which has high bending stiffness and is suitable for situations where the spacing between the reinforcing plates 2 is large. In another embodiment, the stiffening rib 3 is made of an L-shaped profile, which facilitates corner installation. In yet another embodiment, the stiffening rib 3 is made of a rectangular profile, which is simple to manufacture and suitable for situations where the spacing between the reinforcing plates 2 is small and the load is low. However, this is not limiting, and the stiffening rib 3 can also be made of profiles with other cross-sectional shapes. In this embodiment, the stiffening rib 3 only penetrates the reinforcing plate 2 and does not extend to the top 11, mainly serving to constrain the reinforcing plate 2 to prevent its deformation. However, this disclosure is not limited to this, and in alternative embodiments, it is conceivable that both ends of the stiffening rib 3 extend to the top 11 and bottom 12 of the main beam body 1, respectively, and are fixedly connected to the inner surfaces of the top 11 and bottom 12. In this way, the concentrated lifting load can be transferred to the top 11 through the bottom 12 and the stiffening rib 3, further improving the load distribution effect.

[0042] The cross-grid structure formed by the stiffening plate 2 and the stiffening rib 3 has a synergistic effect: the stiffening plate 2 disperses the concentrated load in the horizontal direction, reducing the local out-of-plane bending stress of the main load-bearing component to below the yield limit; the stiffening rib 3 constrains the stiffening plate 2 in the vertical direction, preventing the stiffening plate 2 from buckling locally. If there is only the stiffening plate 2 without the stiffening rib 3, the stiffening plate 2 may buckle under high concentrated loads; if there is only the stiffening rib 3 without the stiffening plate 2, the concentrated load cannot be effectively dispersed in the horizontal direction, and the local bending stress of the main load-bearing component will still exceed the design margin.

[0043] like Figure 1As shown, a supporting truss 4 is also provided inside the main beam body 1. The supporting truss 4 is located in the inner cavity of the main beam and fixed to the inner frame 14 to improve the overall rigidity and deformation resistance of the main beam body 1. Preferably, the supporting truss 4 is arranged in the upper region of the inner cavity of the main beam and is located in the inner frame 14. The supporting truss 4 is a triangular truss, with its three vertices fixed to the inner frame 14 respectively. Specifically, two of the three vertices are fixed to the two sides of the inner frame 14, and the third vertex is fixed at the top center of the inner frame 14. The supporting truss 4 is preferably arranged in the mid-span region of the main beam body 1 because the mid-span region of the main beam has the largest bending moment and the most significant deformation under the overall bending action. However, this is not limiting; the supporting truss 4 can also be arranged at multiple different locations on the main beam body 1; the supporting truss 4 can also adopt other truss forms, such as a rectangular truss or a K-shaped truss. The cross-sectional form of the members supporting truss 4 is not restricted. For example, conventional profiles such as steel pipes, angle steel or H-beams can be used. The connection between members can be achieved by welding, bolting or gusset plate connection.

[0044] The main beam body 1 also has a binding point area for connecting the binding device. In the binding point area, binding structural members such as binding retainers are fixed to the main beam body 1 to enhance the structural strength, thereby enhancing the main beam's ability to withstand binding restraint forces and dynamic load impacts from wind and waves, and preventing local damage to the main beam and loosening of the binding points during the binding process. In addition, it is also possible to consider locally increasing the cross-sectional thickness of the top 11, bottom 12 and / or paired sides 13 of the main beam body 1 to further improve the structural strength.

[0045] Examples of methods for strengthening the main beam structure of gantry cranes are as follows: - Provide the main beam body 1; - The stress on the main beam body 1 under the lifting condition of the lifting device is calculated by finite element analysis. The load magnitude, force direction distribution and stress distribution are obtained. Based on this, the number and distribution range of the reinforcing plates 2 set in the lifting contact area, the scheme for increasing the thickness of the main beam body section in the binding point area, and the installation position of the support truss are determined. - Based on the stress analysis results, a reinforcing plate 2 is installed in the lifting contact area, preferably using double-sided full welding; the stiffening rib 3 is then welded into place. - Secure the tying structure in the tying point area.

[0046] Although various embodiments of the invention have been described in the accompanying drawings with reference to structural examples based on the sea loading and lashing operations of ultra-large gantry cranes, it should be understood that the embodiments within the scope of the invention can be applied to large lifting equipment transportation systems or methods with similar structures and / or functions, such as the transportation of bridge cranes, tower cranes, or gantry cranes, as long as it is necessary to ensure the structural stability of the main beam under the simultaneous action of concentrated jacking loads and periodic lashing dynamic loads in these devices.

[0047] The foregoing description has already given numerous features and advantages, including various alternative implementations, as well as details of the structure and function of the apparatus and method. The intent of this document is exemplary and not exhaustive or limiting. It will be apparent to those skilled in the art that various modifications can be made within the full scope indicated by the broad superordinate meaning of the terms expressed in the appended claims, particularly in terms of structure, materials, elements, components, shapes, dimensions, and arrangement of components, including combinations of these aspects within the scope of the principles described herein. Such various modifications are intended to be included herein without departing from the spirit and scope of the appended claims.

Claims

1. A gantry crane main beam structure, comprising a main beam body, the main beam body including a top and a bottom extending parallel to each other, and having a lifting contact area that contacts a lifting device in a transport state. In the lifting contact area, multiple reinforcing plates and multiple stiffening ribs are fixedly installed inside the main beam body. The plurality of reinforcing plates are arranged longitudinally in parallel with each other, wherein, Each reinforcing plate extends parallel to the top and bottom of the main beam body; The multiple stiffening ribs penetrate vertically through the multiple reinforcing plates, providing support for the multiple reinforcing plates.

2. The gantry crane main beam structure according to claim 1, characterized in that, The main beam body also includes: The paired side portions are connected between the top and the bottom, and the three together form the inner cavity of the main beam; An inner frame is disposed within the cavity of the main beam and fixed to the top, the bottom, and the paired sides.

3. The gantry crane main beam structure according to claim 2, characterized in that, The plurality of reinforcing plates are disposed in the lower region of the inner cavity of the main beam, each reinforcing plate passing through the inner frame and fixed at both ends to the paired sides.

4. The gantry crane main beam structure according to claim 3, characterized in that, Each reinforcing plate has a through hole for the stiffening rib to pass through.

5. The gantry crane main beam structure according to claim 2 or 4, characterized in that, The plurality of stiffening ribs are disposed between the inner frame and the paired sides, and each of the stiffening ribs extends upward from the bottom.

6. The gantry crane main beam structure according to claim 1, characterized in that, The stiffening ribs are composed of T-shaped profiles, L-shaped profiles, or rectangular cross-section profiles.

7. The gantry crane main beam structure according to claim 2, characterized in that, It also includes a support truss, which is disposed in the inner cavity of the main beam and fixed to the inner frame.

8. The gantry crane main beam structure according to claim 7, characterized in that, The supporting truss is located in the upper region of the main beam cavity and within the inner frame. The supporting truss is a triangular truss, with its three vertices fixed to the inner frame.

9. The gantry crane main beam structure according to claim 2, characterized in that, The main beam body also has a binding point area for connecting the binding device, and a binding structure is fixed in the binding point area.

10. A method for strengthening the main beam structure of a gantry crane, comprising: A main beam body is provided, the main beam body including a top and a bottom extending parallel to each other; Determine the lifting contact area where the main beam body contacts the lifting device in the transportation state; In the lifting contact area, multiple reinforcing plates and multiple stiffening ribs are fixedly installed inside the main beam body. The multiple reinforcing plates are arranged longitudinally parallel to each other, wherein each reinforcing plate extends parallel to the top and bottom of the main beam body. The multiple stiffening ribs penetrate vertically through the multiple reinforcing plates, providing support for the multiple reinforcing plates.

11. The method for strengthening the main beam structure of a gantry crane according to claim 10, characterized in that, The load, force direction distribution, and stress distribution in the lifting contact area are calculated by finite element analysis, and the number and distribution range of the reinforcing plates in the lifting contact area are determined accordingly.

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