CN206345605U - Truss-like bank bridge girder and truss-like bank bridge - Google Patents

Abstract

The utility model provides a main girder of a truss type quay bridge and a truss type quay bridge. The main girder includes a sea side girder and a land side girder, and the sea side girder and the land side girder respectively include two parallel upper chords and two lower chords Rods, upper chords and lower chords are located at the four corners of the square, and the two side walls of the main girder are respectively composed of multiple webs fixed between the upper and lower chords; the upper walls of the sea side girder and the land side girder It is composed of a plurality of upper struts fixedly arranged between two upper chords; the lower walls of the sea side girder and the land side girder are composed of a plurality of lower struts fixedly arranged between two lower chords. The main girder of the truss type quay bridge provided by the utility model and the quay bridge using this main girder structure effectively reduce the windward area of the main girder, reduce the wind load and the wheel pressure reaction force of the quay bridge produced, and reduce the The main girder shakes or deforms when it is facing the wind, and has good torsion resistance and fatigue resistance. At the same time, the weight of the main girder is greatly reduced, but it can still maintain the same bearing capacity as the common solid web beam.

Description

Truss type quay bridge girder and truss type quay bridge

technical field

The utility model relates to the field of construction machinery, in particular to a main girder of a truss type quay bridge and a truss type quay bridge.

Background technique

Quay cranes, also known as quayside container cranes and bridge cranes, are equipment used to load and unload containers on ships on the shore, and play an irreplaceable role in the port container loading and unloading system. With the acceleration of the international trade process, the increase of port cargo volume and the development of large-scale container transport ships, newer and higher requirements are put forward for shore-side container cranes. In the prior art, the girder structure mostly adopts a solid-web box-shaped girder. The girders of the solid-belly box-shaped structure are mostly square cubes or cubic columns. The quay bridge using the solid-belly girder not only has heavy weight and high energy consumption, but also has a large windward area of the solid-belly girder, resulting in wind loads on the quay bridge. Large, it will have an adverse effect on the overall structure of the quay crane, and also generate greater working wheel pressure.

In order to solve the aforementioned heavy weight problem of the quay bridge equipment, in the prior art, there are a few quay bridges that use a plate girder and truss combined structure main girder to reduce the weight of the quay bridge. Setting it as a truss structure can reduce the weight of the quay crane equipment to a certain extent, but this weight reduction is limited, and both sides are still plate-shaped structures, which still have the problems of large windward area and high energy consumption, and this plate girder Most of the main girders combined with trusses can only be used for small quay cranes with small parameters and low work levels. In order to further reduce the weight of the quay bridge itself and reduce the windward area, in the prior art, some quayside bridges also adopt a main girder whose front girder is a triangular tube truss structure and the rear girder is a box-shaped plate girder structure.

Disclosed a light-duty small quay bridge as China's utility model patent application (publication number CN105398951A), comprising four columns, two connecting beams on the left and right sides, two lower beams in the front and rear directions, a front girder, and a rear girder; the front girder and The rear beam is installed above the four columns, the front beam is located in front of the four columns, and the rear beam is located behind the four columns; The column is connected, and the two lower beams are located under the column; the cross-section of the column, the connecting beam and the lower beam is circular. According to the utility model patent, it is obvious that the front girder and the rear girder are box structures, and their side walls are all solid plates. Although the application claims to reduce the weight of the girder by changing the cross-sectional shape of the beam and the column, the girder still uses a box body. The structure is heavy and has a large windward area, and it will still bear a large wind force in actual use, which will have an adverse effect on the structure.

Another example is the Chinese Utility Model Patent Application (publication number: CN103318781A) which discloses a folding arm girder crane. , the outer girder of the folding arm is a truss structure, and the inner girder of the folding arm is a double-box trapezoidal beam structure, that is, the outer girder of the folding arm crane provided by the utility model is a truss structure on the sea side, and the folding arm on the land side is a truss structure. The inner girder still adopts the conventional double-box trapezoidal girder structure. While ensuring the rigidity of the girder, the truss structure will be 20% to 30% lighter in weight than the box structure with the same requirements. The folding arm girder crane provided by the utility model patent document sets the outer girder of the folding arm as a truss structure , although it can reduce the weight of the quay crane itself, reduce the energy consumption of the quay crane, and can also reduce the windward area accordingly, but because the inner girder and the rear girder of the folding arm are still double-box trapezoidal girder structures, the reduced weight of the quay crane itself 1. The use of energy consumption and the windward area are limited, and the rear girder still has the problems of heavy weight, large windward area, and high energy consumption.

It can be seen from the above patent application that by setting the upper and lower girders of the front girder or the rear girder as a truss structure, although the weight of the quay bridge itself can be reduced correspondingly, and the corresponding windward area can also be reduced, but due to the left and right girders of the rear girder or the rear girder The beam still adopts the solid web plate beam structure, so that the rear girder still has the problems of heavy weight, high energy consumption and large windward area. Therefore, how to reduce the weight of the girder itself, reduce the windward area of the girder, and at the same time make the lightweight girder still applicable to large-scale quayside bridges with large parameters and high work levels, and ensure a high load capacity, has become an urgent problem to be solved in this field one.

Utility model content

In order to solve the above problems, the purpose of this utility model is to provide a main girder of a truss type quay bridge, including a sea side girder located above the sea surface and a land side girder located above the land, the sea side girder and the land side girder are arranged in parallel, and the sea side girder The side girder and the land side girder are hinged, and the sea side girder can rotate relative to the land side girder around the hinge. Viewed from the end face, two upper chords and two lower chords are located at the four corners of the square, and the two side walls of the sea side girder and the land side girder are respectively composed of multiple webs fixed between the upper and lower chords. Composition; the upper wall of the sea side girder and the land side girder is composed of a plurality of upper struts fixedly arranged between two upper chords; The lower strut constitutes.

The main girder of the truss type quay bridge provided by the utility model effectively reduces the windward area of the main girder, reduces the wind load and the wheel pressure reaction of the quay bridge, and reduces the shaking or deformation of the main girder when it faces the wind , good torsion resistance and fatigue resistance, and further, the main girder structure involved in the utility model effectively and greatly reduces the weight of the main girder, but can still maintain the same load-carrying capacity as the solid web beam, and has a relatively Strong bearing capacity and resistance to deformation.

Preferably, the upper chord and the web are "H" shaped steel or I-shaped steel, and the section heights of the upper chord and the web are equal.

Further, the upper brace and the lower brace are rods or pipes.

Preferably, the webs, upper struts and lower struts on the four walls of the sea side girder and the land side girder are distributed in a triangular or "N" or "K" or "m" shape along the axial direction of the main girder. , and on the four walls of the sea-side girder and the land-side girder, the vertices of any triangle formed by webs, upper struts, or lower struts respectively meet the centroid axes of the upper/lower chords.

Further, between the two upper chords and between the two lower chords, a plurality of horizontal support rods perpendicular to the upper and lower chords are respectively arranged, and the ends of the horizontal support rods are at the same point or at the same point as the vertices of the triangle formed by the webs. In the vertical plane, the triangle intersection formed by the upper struts on the upper wall meets the axis of the horizontal support rods, and the triangle intersection formed by the lower struts on the lower wall meets the axis of the horizontal support rods.

Preferably, one or more diagonal bracing rods are obliquely arranged in the sea side girder and the land side girder respectively, and the diagonal bracing rods form a triangular structure with the web members and/or the horizontal supporting rods.

Further, the diagonal brace is arranged on the horizontal support rod, and the diagonal brace and the web are located on the same plane, one end of the diagonal brace is fixedly connected to the horizontal support rod located at the upper end of the web, and the other end of the diagonal brace is connected to the The horizontal support bar at the lower end of the web bar is fixedly connected.

Preferably, the number of diagonal braces is the same as the number of horizontal braces.

Further, the diagonal brace is a pipe.

Preferably, the bottom chord is provided with a track for the load-carrying device to slide along the axial direction of the main girder, and the track is arranged on the outer side of the web members of the two side walls.

The utility model also provides a truss-type quay bridge, which includes a portal frame, the above-mentioned main girder, a ladder frame and multiple tie rods for pulling the main girder. On the beam, the other end of the pull rod is fixedly arranged on the ladder frame at the top of the column of the door frame.

As mentioned above, the main girder of the truss type quay bridge involved in the utility model is simple, the construction cost is low, the self weight and the windward area of the quay bridge are reduced, the energy consumption and the use cost of the quay bridge equipment are reduced, and it can be widely applied to large parameters, Among the high-level large-scale quay cranes, the practicability of large-scale quay crane equipment has been improved, and it is worthy of widespread promotion and use.

In order to make the above content of the present invention more obvious and understandable, the preferred embodiments will be described in detail below in conjunction with the accompanying drawings.

Description of drawings

Below will introduce the utility model in conjunction with accompanying drawing.

Fig. 1 is the structural representation of the truss type quay bridge of the present utility model;

Fig. 2 is the front view of Fig. 1;

Fig. 3 is a schematic diagram of the rotation of the sea side girder 11 relative to the land side girder 12 in Fig. 2;

Figure 4-1 is a top view of the landside girder 12;

Figure 4-2 is a front view of the landside girder 12;

Figure 4-3 is a bottom view of the landside girder 12;

Figure 5-1 is a top view of the sea side girder 11;

Figure 5-2 is a front view of the sea side girder 11;

Figure 5-3 is a bottom view of the sea side girder 11;

Figure 6 is a cross-sectional view of the main beam.

Component designation description

1 main beam

11 Sea side girder

12 Land side girder

13 top chord

14 bottom chord

15 web bar

16 hinge

17 Connection connector

171 Auxiliary support rod

18 horizontal support rod

19 upper strut

10 lower struts

2 masts

21 uprights

22 Upper beam

23 tie rod

24 ladder frame

3 Diagonal braces

4 tracks

detailed description

The implementation of the present utility model is illustrated by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. Although the description of the utility model will be introduced together with the preferred embodiment, it does not mean that the features of the utility model are limited to the embodiment. On the contrary, the purpose of introducing the utility model in conjunction with the embodiments is to cover other options or modifications that may be extended based on the claims of the utility model. The following description contains numerous specific details in order to provide an in-depth understanding of the present invention. The invention can also be implemented without these details. In addition, in order to avoid confusion or obscure the key points of the present invention, some specific details will be omitted in the description.

In the description of the present utility model, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a flexible connection. Detachable connection, or integral connection; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

In addition, "up", "down", "left", "right", "top", and "bottom" used in the following description should not be interpreted as limiting the present invention.

The utility model relates to a main girder of a truss type quay bridge, and the truss type quay bridge main girder involved in the utility model is preferably suitable for a medium-sized or large quay bridge, that is, the outreach of the quay bridge is 40m-65m.

As shown in Figures 1 to 6, the utility model relates to a main girder of a truss type quay bridge, which includes a sea side girder 11 located above the sea surface and a land side girder 12 located above the land, the sea side girder 11 is parallel to the land side girder 12 Setting, that is, the main girder 1 of the truss-type quay bridge is a straight beam, and by hoisting the loading device under the main girder 1, the container or other goods on the freighter are lifted and transported to land for unloading; Or hoist the container or other goods on land to the freighter for loading. In the present utility model, the rated load of the loading device is preferably 35t-65t.

In the present utility model, the sea side girder 11 and the land side girder 12 are similar in structure, both of which are cubic structures, and the four walls of the cube are composed of four trusses. Specifically, the sea side girder 11 and the land side girder 12 respectively include Two upper chords 13 and two lower chords 14 arranged in parallel, viewed from the end face of the main girder 1, the two upper chords 13 and the two lower chords 14 are located at the four corners of the square.

Further, in the present utility model, the sea side girder 11 and the land side girder 12 are hinged, through the hinge, the sea side girder 11 can rotate around the hinge 16 relative to the land side girder 12, when there is a height exceeding the height of the main girder 1 When the freighter needs to pass, the sea side girder 11 can be lifted, thereby avoiding the collision between the sea side girder 11 and the container or goods on the freighter.

Furthermore, in order to prevent the sea side girder 11 from interfering with the land side girder 12 when rotating around the hinge 16, the length of the upper chord 13 of the sea side girder 11 and the land side girder 12 is shorter than the lower chord 14, and the sea side The outer two ends of the girder 11 and the land side girder 12 are perpendicular to the horizontal plane, and the opposite sides of the sea side girder 11 and the land side girder 12 at the hinge 16 are at a certain angle to the horizontal plane, ensuring that when the sea side girder 11 is pulled When lifting, the sea side girder 11 will not interfere with the land side girder 12 to cause danger, thus ensuring the safety of the main girder 1 .

Further, since the load-carrying device needs to be hoisted under the main girder 1, a rail 4 for the load-carrying device to slide must be provided on the main girder 1, so that the load-carrying device can run to transport goods. In the present utility model, it is preferable to arrange the track 4 on the outer side of the two side walls, so as to avoid interference with the load-carrying device, and at the same time facilitate the laying of the track and the daily maintenance of the track. Furthermore, in the present utility model, the track 4 is arranged on the two lower chords 14, and the loading device is preferably a suspended trolley.

In the present invention, the sea-side girder 11 and the land-side girder 12 of the cube structure respectively have two side walls perpendicular to the sea level and an upper wall and a lower wall parallel to the sea level. The two side walls of the sea-side girder 11 and the land-side girder 12 are respectively composed of a plurality of webs 15 fixedly arranged between the upper chord 13 and the lower chord 14 . The upper walls of the sea side girder 11 and the land side girder 12 are composed of a plurality of upper struts 19 fixedly arranged between two upper chords 13; A plurality of lower braces 10 between 14 constitute.

In the present invention, in order to further improve the bearing capacity of the main girder of the truss, H-shaped steel or I-shaped steel is preferably used as the upper chord 13 and the web 15 . Further, in order to be more convenient during assembly, the section heights of the H-shaped steel or I-beam adopted by the upper chord 13 and the web 15 are equal, and when the section heights of the upper chord 13 and the web 15 are equal, the Node-connected joints have better fatigue resistance.

Furthermore, in the present utility model, since rods or pipes are common building materials, they are easy to obtain and inexpensive, but have good structural stability. Therefore, the upper strut 19 and the lower strut 10 are preferably rods or pipes. Specifically, in the present utility model, the cross-sectional shape of the rod or pipe can be selected according to the actual situation.

In the present utility model, the 15 webs, the 19 upper struts and the 10 lower struts on the four walls of the sea side girder 11 and the land side girder 12 respectively form a triangle or " N" type or "K type" or "m" type distribution, and on the four walls of the sea side girder 11 and the land side girder 12, any triangle formed by the web 15 or the upper strut 19 or the lower strut 10 respectively The vertices of the upper and lower chords 13/14 converge with the centroid axes respectively.

Specifically, among the two side walls of the main girder 1, one end of the web 15 is fixedly connected to the upper chord 13, the other end of the web 15 is fixedly connected to the lower chord 14, and each web 15 is connected end to end in a zigzag shape distribution, forming a Warren truss structure, the vertex of any triangle formed by webs 15 located on the upper part of the side wall meets the centroid axis of the upper chord 13, and any triangle formed by webs 15 located on the lower part of the side wall The apex of the chord and the centroid axis of the lower chord 14 meet.

Further, in the upper wall of the main beam 1, both ends of the upper strut 19 are respectively fixedly connected with two upper chords 13, and the triangular intersection formed by the axes of the two upper struts 19 meets the centroid axis of the upper chord 13; In the lower wall of the main beam 1 , both ends of the lower strut 10 are respectively fixedly connected with two lower chords 14 , and the triangle intersection formed by the axes of the two lower struts 10 meets the centroid axis of the lower chord 14 .

Furthermore, in order to make the structure of the main girder 1 more stable, a plurality of horizontal support rods 18 perpendicular to the upper and lower chords 13 and 14 are respectively provided between the two upper chords 13 and the two lower chords 14. The end of the support rod 18 is at the same point as the apex of the triangle formed by the web rod 15 or in the same vertical plane, and the intersection point of the triangle formed by the upper support rod 19 on the upper wall meets the axis of the horizontal support rod 18. The intersection point of the triangle formed by the lower brace 10 meets the axis of the horizontal support rod 18 . The horizontal support bar 18 can further increase the anti-instability performance of the upper and lower two trusses of the main girder 1 .

In the utility model, since the 15 webs, the 19 upper struts and the 10 lower struts on the four walls are respectively in the shape of a triangle or "N" type or "K type" or The "m" shape is distributed, so two adjacent webs 15 or upper struts 19 or lower struts 10 respectively form a triangular structure with the upper chord 13 or lower chord 14 to make the truss structure more stable. Further, the vertices of any triangle formed by the web rods 15 at the top of the two side walls are at the same point as the vertices of the triangles on the upper wall or in the same vertical plane, any triangle formed by the web rods 15 at the bottom of the two side walls The apex of a triangle is at the same point or in the same vertical plane as the apex of the triangle of the lower wall, so that the structure of the truss is more stable and the main girder 1 is more beautiful.

In the present utility model, it is preferable to connect the web bar 15 , the upper strut 19 , the lower strut 10 and each horizontal support bar 18 with the upper chord 13 and the lower chord 14 by welding.

In the present utility model, in order to further increase the structural stability and torsion resistance of the main girder 1, one or more diagonal braces 3 are obliquely arranged in the sea side girder 11 and the land side girder 12 respectively, and the diagonal braces 3 utilize The stability of the triangle is improved, and a triangle structure is formed with the web members 15 and/or the horizontal support rods 18 to increase the torsional rigidity of the main girder 1. In the present utility model, the diagonal strut 3 is preferably a pipe fitting, and the pipe fitting as the diagonal strut is not only convenient for obtaining materials, but also can be easily welded with any shape of the welding surface, and the matching degree is high.

Further, in the present utility model, the horizontal support bar 18 located between the two upper chords 13 is preferably made of pipe material, which is convenient to obtain and welded; the horizontal support bar 18 located between the two lower chords 14 is preferably made of H-shaped steel or I-shaped Steel, and the cross-section height of H-shaped steel or I-beam is the same as that of the lower chord 14, so that the loads borne by the two rails 4 on the lower chord 14 can be balanced, and at the same time, the main girder 1 The weight of the main girder 1 is further reduced under the condition of increasing the strength.

Further, in the present utility model, preferably, the diagonal brace 3 is arranged on the horizontal support rod 18, and the diagonal brace 3 and the web 15 are located on the same plane, and one end of the diagonal brace 3 is connected to the upper end of the web 15. The horizontal support bar 18 is fixedly connected, and the other end of the diagonal support bar 3 is fixedly connected with the horizontal support bar 18 located at the lower end of the web bar 15 .

Furthermore, in the present utility model, the number of diagonal struts 3 is preferably multiple, and is the same as the number of horizontal support rods 18, that is, one diagonal strut 3 is respectively set on each horizontal support rod 18, to further increase the main The bearing capacity and anti-instability performance of beam 1.

The utility model also discloses a truss-type quay bridge, as shown in Fig. 1-Fig. Set on the door frame 2 , one end of a plurality of pull rods 23 is respectively fixed at different positions of the main beam 1 , and the other ends of the pull rods 23 are all fixedly arranged on the ladder frame 24 at the top of the column 21 of the door frame 2 .

Furthermore, in the present utility model, the upper beam 22 is arranged in the portal frame 2 , and the land side girder 12 is fixed to the bottom of the upper beam 22 through the connection joint 17 and the auxiliary support rod 171 . The connecting joint 17 is a closed box structure, the width of the closed box is the same as the section width of the upper beam 22 , and the thickness of the closed box is the same as the section height of the upper chord 13 . Here, the width of the closed box is set to be the same as the width of the cross-section of the upper beam 22, so that the upper beam 22 and the closed box can be firmly fixed, and the thickness of the closed box is set to be the same as that of the upper chord. The section heights of the rods 13 are the same, so that the closed box matches the upper chord 13 , so that the closed box can be welded into the upper chord 13 to become a component of the upper chord 13 . Furthermore, the two bottom edges of the bottom surface of the closed box are fixedly connected to the upper chord 13 and the lower chord 14 respectively through a plurality of auxiliary support rods 171 (as shown in Figure 4-2), that is, each bottom edge of the closed box bottom A bottom edge is connected with both the upper chord 13 and the lower chord 14, so as to improve the bearing capacity of the closed box, thereby further improving the bearing capacity of the land side girder 12 at the connection position with the upper beam 22.

The main girder of the truss-type quay bridge provided by the utility model adopts a truss structure, which not only ensures the stability and load of the truss-type girder, but also further reduces the weight and windward area of the quay bridge itself, and further reduces the equipment of the quay bridge. energy consumption and usage costs.

In summary, the main girder of the truss-type quay bridge and the quay bridge with the truss-type main girder involved in the utility model are simple in structure, the construction process is simple, and the production cost is greatly reduced. In addition, the truss-type quay bridge and the quay bridge involved in the utility model The main girder of the quay bridge has good load-bearing performance, good torsion resistance and fatigue resistance, safe and reliable, and is worthy of widespread use.

The above-mentioned embodiments only illustrate the principles and effects of the present utility model, but are not intended to limit the present utility model. Those skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present utility model. Therefore, all equivalent modifications or changes made without departing from the spirit and technical ideas disclosed in the utility model should still be covered by the claims of the utility model.

Claims (11)

1. A main girder of a truss type quay bridge, comprising a sea side girder positioned above the sea surface and a land side girder positioned above the land, the sea side girder is arranged in parallel with the land side girder, and the sea side girder is connected to the land side girder The girder on the land side is hinged, and the girder on the sea side can rotate relative to the girder on the land side around the hinge by being hinged. Viewed from the end face of the main girder, the two upper chords and the two lower chords are located at the four corners of the square, and the sea side girder and the land side girder The two side walls of the two side walls are respectively composed of a plurality of webs fixedly arranged between the upper and lower chords; It is composed of a plurality of upper struts; the lower walls of the sea side girder and the land side girder are composed of a plurality of lower struts fixedly arranged between the two lower chords. 2. The main girder of the truss type quay bridge according to claim 1, wherein the upper chord and the web are "H" shaped steel or I-shaped steel, and the upper chord and the web are Section heights are equal. 3. The main girder of the truss type quay bridge according to claim 1, wherein the upper brace and the lower brace are rods or pipes. 4. The main girder of the truss type quay bridge according to claim 3, wherein the web members, the upper struts and the lower girders on the four walls of the sea side girder and the land side girder The struts are distributed in a triangular or "N" shape or "K shape" or "m" shape along the axial direction of the main girder, and are respectively formed on the four walls of the sea side girder and the land side girder. The vertices of any triangle formed by the webs, the upper struts or the lower struts meet the centroid axes of the upper/lower chords respectively. 5. The main girder of the truss type quay bridge according to claim 4, characterized in that, between the two described upper chords and between the two described lower chords, a plurality of horizontal bars perpendicular to the upper and lower chords are arranged respectively. A support rod, the end of the horizontal support rod is at the same point as the apex of the triangle formed by the web rod or in the same vertical plane, and the intersection point of the triangle formed by the upper support rod on the upper wall and the horizontal The axes of the support rods meet, and the triangle intersection point formed by the lower support rods on the lower wall meets the axes of the horizontal support rods. 6. The main girder of the truss type quay bridge according to claim 5, characterized in that, one or more diagonal braces are obliquely arranged in the sea side girder and the land side girder respectively, and the diagonal braces A triangular structure is formed with the web bars and/or horizontal support bars. 7. The main girder of the truss-type quay bridge according to claim 6, wherein the diagonal brace is arranged on the horizontal support rod, and the diagonal brace and the web are located on the same plane, so One end of the diagonal brace is fixedly connected to the horizontal support rod located at the upper end of the web, and the other end of the diagonal brace is fixedly connected to the horizontal support rod located at the lower end of the web. 8. The main girder of the truss type quay bridge according to claim 7, wherein the number of the diagonal bracing rods is the same as the number of the horizontal supporting rods. 9. The main girder of the truss-type quay bridge according to claim 6, wherein the diagonal braces are pipe fittings. 10. The main girder of the truss type quay bridge as claimed in claim 1, wherein the lower chord is provided with a track for the load-carrying device to slide along the axial direction of the main girder, and the track is arranged on two outside of the side wall. 11. A truss-type quay bridge, characterized in that it comprises a gantry, a main girder as claimed in any one of claims 1-10, a ladder frame and a plurality of tie rods for pulling the main girder, and the land side The girder is fixedly arranged on the door frame, one ends of the plurality of tie rods are respectively fixed on the main beam, and the other ends of the tie rods are all fixedly arranged on the ladder frame at the top of the column of the door frame.