Steel box girder and manufacturing method thereof

Abstract

The application relates to the field of bridge construction, in particular to a steel box girder and a manufacturing method thereof, which comprises a top plate, the bottom surface of the top plate is fixed with the top of a plurality of top plate U ribs, the bottom of the top plate U rib is fixed on the top of a plurality of transverse plates, the bottom of the transverse plate is fixed on a bottom plate, a plurality of groups of web plates are fixed on the bottom plate, each group of web plates is composed of two inverted V-shaped web plates, the bottom of the web plate is fixed on the bottom plate, the web plate separates the left and right adjacent transverse plates, the two ends of the transverse plate are provided with a plurality of cantilever arms, a plurality of temperature adjusting mechanisms are arranged between the top plate and the bottom plate, the temperature adjusting mechanisms are arranged to adjust the temperature of the top plate and the bottom plate, the situation of thermal expansion and cold contraction caused by the excessively high, excessively low or sudden temperature change of the top plate and the bottom plate is avoided, the steel box girder is well protected, and the service life of the steel box girder is greatly prolonged.

Description

Technical Field

[0001] This invention relates to the field of bridge construction, and more particularly to a steel box girder and its manufacturing method. Background Technology

[0002] Steel box girders, also known as steel plate box girders, are a common structural form for long-span bridges. They are generally used on bridges with large spans and are called steel box girders because of their box-like shape. For example, patent application number CN202011204086.1 discloses a steel box girder bridge and its manufacturing method. While this type of steel box girder bridge offers advantages such as reducing steel consumption, facilitating cambering and formwork support of the bridge deck, reducing the likelihood of cracking of the bridge deck, and minimizing the impact of the bridge deck on the top of the beam, thus reducing the risk of cracking due to rigid collisions during simultaneous contraction or expansion, and providing some vibration reduction and energy absorption, the problem of thermal expansion and contraction remains unresolved. There are no effective protective measures against thermal expansion and contraction, especially in areas with large diurnal temperature variations, where this is particularly pronounced. This can easily lead to deformation of the steel box girder bridge, affecting its structural stability and safety, thereby reducing the bridge's service life and causing it to prematurely reach the end of its service life. Patent application CN202210328829.9 discloses a multi-plate unit structure and assembly manufacturing method for steel box girders. While this method improves production efficiency, reduces construction difficulty, and saves production costs and workload, it cannot solve the problem of thermal expansion and contraction in the manufactured steel box girders. Patent application CN202110695195.6 discloses a method for manufacturing and pre-assembling double-sided box-girder steel-concrete composite beams, but this patent also lacks a corresponding structural solution to address the thermal expansion and contraction issue. Therefore, there is an urgent need for a method that can effectively solve the problem of thermal expansion and contraction in steel box girders during use. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a steel box girder and its manufacturing method, solving the problems existing in the prior art. The present invention regulates the temperature of the top plate and the bottom plate through the setting of a temperature adjustment mechanism, avoiding thermal expansion and contraction caused by excessively high or low temperatures or sudden temperature changes in the top and bottom plates, thus providing excellent protection for the steel box girder and greatly improving its service life.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: a steel box girder, comprising a top plate, the top of several top plate U-ribs fixed on the bottom surface of the top plate, the bottom of the top plate U-ribs fixed on the top of several transverse diaphragms, the bottom of the transverse diaphragms fixed on a bottom plate, several sets of web plate assemblies fixed on the bottom plate, each web plate assembly consisting of two inverted V-shaped web plates, the bottom of the web plates fixed on the bottom plate, and the web plates separating the adjacent transverse diaphragms on the left and right sides, with several cantilever arms at both ends of the transverse diaphragms, and several temperature regulating mechanisms provided between the top plate and the bottom plate.

[0007] Preferably, the temperature regulating mechanism includes a top plate U-rib, which is hollow, with the upper ends of hollow columns connected to both ends of the top plate U-rib, and a hollow horizontal tube connecting the lower ends of the two hollow columns. The hollow horizontal tube, hollow columns, and top plate U-rib are filled with fire-resistant balls.

[0008] Preferably, the refractory balls in the top plate U-rib and the hollow horizontal tube are arranged in a horizontal row, and the refractory balls in the two hollow columns are arranged in a vertical row. There is a gap between the top of the uppermost refractory ball in the left hollow column and the inner top surface of the hollow horizontal tube. An elastic partition is provided in the top plate U-rib. The left end of the elastic partition is fixed to the left inner wall of the left top plate U-rib, and its right end is fixed to the right end of the inner bottom surface of the top plate U-rib. The elastic partition gradually slopes downward from left to right, and a through hole for the refractory balls to pass through is opened at its left end. A ball pushing mechanism is provided at the bottom of the left hollow column, and an elastic limiting ring is provided in the left hollow column.

[0009] Preferably, the ball-pushing mechanism includes a protective box fixed to the bottom of the hollow column on the left side, a cylinder fixed inside the protective box, a 7-shaped push plate fixed to the end of the cylinder's telescopic rod, and a lifting channel for the 7-shaped push plate opened at the bottom of the hollow column.

[0010] Preferably, the height of the gap is 1.5-2 times the diameter of the refractory ball.

[0011] Preferably, the elastic partition 1 is made of rubber, and the through hole is circular with a diameter slightly smaller than that of the fire-resistant ball.

[0012] Preferably, the inner bottom surface of the hollow horizontal tube gradually slopes upward from left to right.

[0013] Preferably, the elastic partition has a cavity inside, the inner wall of the cavity is lined with an isolation layer, and the space enclosed by the isolation layer is filled with fireproof sealant.

[0014] Preferably, a layer of fire-resistant adhesive is fixed on the right inner wall surface of the left hollow column, the inner top surface of the hollow horizontal tube, and the left inner wall surface of the right hollow column.

[0015] Preferably, a method for manufacturing a steel box girder includes the following steps: S1: Produce the top plate, top plate U-rib, transverse diaphragm, bottom plate, web plate, cantilever arm, and hollow column required for assembling the steel box girder. When producing the left hollow column, first fix the elastic limiting ring inside it; S2: Weld the bottom of the bottom plate to the bottom of the web plate; S3: Fix the cantilever arm on the outer surface of the leftmost and rightmost web plates; S4: Weld the transverse diaphragm between adjacent web plates; S5: Weld the hollow horizontal tube to the bottom plate. During welding, first weld the left side plate, right side plate, and top plate of the hollow horizontal tube together, and then weld the three together to the corresponding positions on the bottom plate. This completes the installation of the hollow horizontal tube. The front and rear ends have openings for welding to the hollow columns. Before welding the left side plate, right side plate, top plate and bottom plate, the inner bottom surface of the corresponding part of the bottom plate is first set to be inclined, with the end away from the ball pushing mechanism gradually sloping downwards towards the ball pushing mechanism. S6: Install and fix the ball pushing mechanism on the bottom plate. S7: Weld the hollow columns on the hollow horizontal tube, and put an appropriate number of fire-resistant balls through the upper opening of the hollow columns. S8: Weld the top plate U-rib to the top of the hollow columns, with an opening at the bottom of the top plate U-rib for welding to the top of the hollow columns. S9: Fix the elastic partition inside the top plate U-rib, and place an appropriate number of fire-resistant balls inside it. S10: Weld the top plate to the top plate U-rib.

[0016] (III) Beneficial Effects

[0017] 1. This invention constructs a steel box girder consisting of a top plate, top plate U-ribs, transverse diaphragms, a bottom plate, a web, and cantilever arms. This makes the overall structure of the steel box girder more stable and robust. To further enhance the stability and robustness of the steel box girder structure, an appropriate number of reinforcing ribs can be provided on the transverse diaphragms, bottom plate, web, and cantilever arms. A temperature regulating mechanism is installed between the top plate and the bottom plate to regulate the temperature of the top plate and the bottom plate, preventing thermal expansion and contraction caused by excessively high or low temperatures or sudden temperature changes. This provides excellent protection for the steel box girder and greatly extends its service life.

[0018] 2. This invention fills the interior of hollow horizontal tubes, hollow columns, and the U-ribs of the top plate with fire-resistant balls. These fire-resistant balls act as temperature regulators. When the steel box girder is used in an area with large diurnal temperature variations, and the daytime ambient temperature is too high, causing the temperature of the top plate, bottom plate, and hollow columns to rise, the fire-resistant balls can effectively absorb the heat from these components and store it within the balls. This effectively cools the top plate, bottom plate, and hollow columns, preventing the temperature of the steel box girder from continuously rising with the ambient temperature. Once the temperature of the top plate, bottom plate, and hollow columns is reduced in time and absorbed by the fire-resistant balls, heat will not be transferred to the interior of the steel box girder, thus ensuring the overall temperature of the steel box girder. The stability of the steel box girder is ensured, preventing it from expanding due to temperature increases. When the outside temperature drops at night, causing the top plate, bottom plate, and hollow columns to cool down, the temperature of the refractory balls is higher than that of the top plate, bottom plate, and hollow columns. The heat accumulated by the refractory balls during the day is then released, providing timely heating to the top plate, bottom plate, and hollow columns, preventing them from cooling down with the decrease in outside temperature. This effectively prevents the steel box girder from shrinking due to temperature drops. Therefore, this temperature regulation mechanism effectively regulates the temperature of the steel box girder, avoiding the impact of sudden changes in outside temperature and effectively solving the problem of thermal expansion and contraction of the steel box girder.

[0019] 3. This invention, through the design of elastic baffles, a ball-pushing mechanism, and elastic limiting rings, enables the movement of some of the refractory balls. This movement of the refractory balls accelerates heat absorption and makes heat absorption more uniform, resulting in a more uniform temperature on the outer ring of the steel box girder. The elastic baffles deform during the ball-pushing mechanism's upward push of the refractory balls through the through-hole, simultaneously driving the movement of the refractory balls and accelerating their heat absorption, thus enhancing the cooling effect. Once the refractory balls pass through the through-hole, the elastic baffles, no longer under pushing force, return to their original state. This instantaneous return generates a significant elastic force on the refractory balls. The refractory balls on the partition will undergo a significant bouncing process, which has the following effects: 1) It accelerates the absorption of heat by the refractory balls; 2) This bouncing process allows the refractory balls to contact the inner wall of the top plate, further improving the speed and efficiency of heat absorption; 3) This bouncing process also makes it easier for the refractory balls above the through holes to shift to the right and detach from the through holes, making the through holes more open and facilitating the smooth pushing of the balls next time; 4) Since the top plate directly bears the weight of vehicles, the pressure from vehicles passing over it can easily cause deformation. The up-and-down bouncing of the refractory balls actually exerts an upward striking force on the top plate, which to some extent helps prevent deformation; 5) The elastic partition also provides a certain degree of shock absorption.

[0020] 4. The present invention sets the push plate of the ball pushing mechanism as a 7-shaped push plate. During the extension of the 7-shaped push plate, the horizontal plate of the 7-shaped push plate pushes the fire-resistant ball on it upward, and the vertical plate of the 7-shaped push plate is blocked by the fire-resistant ball on the right side of the upward-pushed fire-resistant ball, so as to prevent it from rolling to the left and prevent it from jamming the telescopic rod, causing the ball pushing mechanism to malfunction.

[0021] 5. This invention incorporates a cavity, an isolation layer, and fire-retardant sealant within the elastic partition. This design ensures that the elasticity of the partition is maintained while simultaneously providing fire protection. In the event of a fire, the elastic partition melts due to increased temperature, but the internal fire-retardant sealant remains intact. The fire-resistant ball and the fire-retardant sealant form a double-layer fire barrier, providing excellent fire protection. Once the elastic partition melts, the ball-pushing mechanism ceases to function properly, triggering an alarm and serving as a fire alarm. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall invention.

[0023] Figure 2 For the present invention Figure 1A schematic diagram after removing the top plate of one of the web plate groups.

[0024] Figure 3 This is a schematic diagram of the temperature regulation mechanism of the present invention.

[0025] Figure 4 This is a schematic diagram of the ball-pushing mechanism of the present invention.

[0026] Figure 5 For the present invention Figure 3 A schematic diagram after removing the ball-pushing mechanism.

[0027] Figure 6 This is an overall cross-sectional view of the elastic partition of the present invention.

[0028] In the diagram: 1-Top plate, 2-Top plate U-rib, 3-Horizontal partition, 4-Bottom plate, 5-Web plate assembly, 6-Web plate, 7-Cantilever arm, 8-Temperature adjustment mechanism, 9-Hollow column, 10-Hollow horizontal tube, 11-Fireproof ball, 12-Gap, 13-Elastic partition, 14-Through hole, 15-Push ball mechanism, 16-Protective box, 17-Cylinder, 18-Telescopic rod, 19-7-shaped push plate, 20-Lifting channel, 21-Cavity, 22-Isolation layer, 23-Fireproof sealant, 24-Fireproof adhesive, 25-Elastic limit ring. Detailed Implementation

[0029] The following will refer to the appendices in the embodiments of the present invention. Figure 1-6 The technical solutions in the embodiments of the present invention have been clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides a technical solution: a steel box girder, including a top plate 1, with the tops of several top plate U-ribs 2 fixed on the bottom surface of the top plate 1, the bottoms of the top plate U-ribs 2 fixed on the tops of several transverse diaphragms 3, the bottoms of the transverse diaphragms 3 fixed on a bottom plate 4, and several sets of web plate groups 5 fixed on the bottom plate 4. Each web plate group 5 consists of two inverted V-shaped web plates 6, the bottoms of which are fixed on the bottom plate 4, and the web plates 6 separate the adjacent transverse diaphragms 3 on the left and right. Several cantilever arms 7 are provided at both ends of the transverse diaphragms 3, and several temperature regulating mechanisms 8 are provided between the top plate 1 and the bottom plate 4. This invention makes the overall structure of the steel box girder more stable and robust by setting the steel box girder to consist of a top plate 1, top plate U-ribs 2, transverse diaphragms 3, bottom plate 4, web plates 6, and cantilever arms 7. In order to make the structure of the steel box girder more stable and robust, an appropriate number of reinforcing ribs can be provided on the transverse diaphragms 3, bottom plate 4, web plates 6, and cantilever arms 7. A temperature regulating mechanism 8 is installed between the top plate 1 and the bottom plate 4 to regulate the temperature of the top plate 1 and the bottom plate 4, preventing thermal expansion and contraction caused by excessively high or low temperatures or sudden temperature changes. This provides excellent protection for the steel box girder and greatly extends its service life.

[0031] The temperature regulating mechanism 8 includes a top plate U-rib 2, which is hollow. The upper ends of hollow columns 9 are connected to both ends of the top plate U-rib 2. A hollow horizontal tube 10 is connected between the lower ends of the two hollow columns 9. The hollow horizontal tube 10, hollow columns 9, and the interior of the top plate U-rib 2 are filled with fire-resistant balls 11. The inclusion of the top plate U-rib 2 in the temperature regulating mechanism 8 makes full use of the hollow structure of the top plate U-rib 2, maximizing resource utilization. Moreover, filling the top plate U-rib 2 with fire-resistant balls 11 can also increase the support of the top plate 1, further preventing the deformation of the top plate 1. The refractory balls 11 play a role in temperature regulation. For example, if the steel box girder is used in an area with large day-night temperature differences, when the outside temperature is too high during the day, causing the temperature of the top plate 1, bottom plate 4, and hollow columns 9 to rise, the refractory balls 11 can absorb the heat from the top plate 1, bottom plate 4, and hollow columns 9 in a timely manner and store the heat inside the refractory balls 11. This effectively cools down the top plate 1, bottom plate 4, and hollow columns 9, preventing the temperature of the steel box girder from rising continuously with the increase in the outside temperature. Once the temperature of the top plate 1, bottom plate 4, and hollow columns 9 can be reduced in time and absorbed by the refractory balls 11, the heat will not be transferred to the interior of the steel box girder. This ensures the overall temperature stability of the steel box girder and prevents it from rising with the increase in the outside temperature, thus effectively preventing the steel box girder from expanding due to temperature increases. When the outside temperature drops at night, causing the top plate 1, bottom plate 4, and hollow columns 9 to cool, the temperature of the refractory balls 11 is higher than that of the top plate 1, bottom plate 4, and hollow columns 9. At this time, the heat accumulated by the refractory balls 11 during the day is released outwards, effectively raising the temperature of the top plate 1, bottom plate 4, and hollow columns 9, preventing them from cooling down with the decrease in ambient temperature. This effectively prevents the steel box girder from shrinking due to temperature drops. Therefore, the temperature regulation mechanism 8 effectively regulates the temperature of the steel box girder, avoiding the impact of sudden changes in ambient temperature on the steel box girder, and effectively solving the problem of thermal expansion and contraction of the steel box girder. The refractory balls 11 can be hollow, which reduces the overall weight of the steel box girder.

[0032] The refractory balls 11 inside the top plate U-rib 2 and the hollow horizontal tube 10 are arranged in a horizontal row, while the refractory balls 11 inside the two hollow columns 9 are arranged in a vertical row. A gap 12 is left between the top of the uppermost refractory ball 11 inside the left hollow column 9 and the inner top surface of the hollow horizontal tube 10. An elastic partition 13 is provided inside the top plate U-rib 2. The left end of the elastic partition 13 is fixed to the left inner wall of the left top plate U-rib 2, and its right end is fixed to the right end of the inner bottom surface of the top plate U-rib 2. The elastic partition 13 extends from left to right. The structure slopes downwards gradually, with a through hole 14 at its left end for the passage of refractory balls 11. A ball-pushing mechanism 15 is located at the bottom of the left hollow column 9, and an elastic limiting ring 25 is located inside the left hollow column 9. The refractory balls 11 in the top plate U-rib 2 and the hollow horizontal tube 10 are arranged in a horizontal row, preventing stacking. The refractory balls 11 in the two hollow columns 9 are arranged in a vertical row, preventing stacking. The gap 12 is designed for fire resistance. The space left for the overall movement of the ball 11 includes an elastic partition 13 that is gradually inclined downwards from left to right. This guides the refractory ball 11 on the elastic partition 13 and simultaneously causes the ball-pushing mechanism 15 to operate at a set time interval. The elastic limiting ring 25 is positioned above the bottommost refractory ball 11 inside the left hollow column 9. In other words, the elastic limiting ring 25 limits the second refractory ball 11 from the bottom to the top inside the left hollow column 9. The elastic limiting ring 25 can be made of elastic rubber band material or silicone, etc. A limiting hole is provided at the center of the elastic limiting ring 25. The diameter of the limiting hole 25 is slightly smaller than the diameter of the refractory ball 11, which is just enough to catch the refractory ball 11 and prevent it from falling below the elastic limiting ring 25, thus providing a good limiting effect. It also facilitates the ball-pushing mechanism 15 to push the bottommost refractory ball 11 inside the left hollow column 9 upwards and through the elastic limiting ring 25.The specific working principle is as follows: When the ball-pushing mechanism 15 is activated, it pushes the refractory ball 11 inside the hollow column 9 on the left upwards. The bottommost refractory ball 11 is pushed above the elastic limiting ring 25, and the topmost refractory ball 11 passes through the through hole 14 and reaches above the elastic partition 13. Then, the ball-pushing mechanism 15 returns to its original position. During the return process, the refractory ball 11 above it is stopped from moving downwards by the elastic limiting ring 25. After the ball-pushing mechanism 15 returns to its original position, a hollow horizontal tube 10 will remain between the ball-pushing mechanism 15 and the elastic limiting ring 25. The space for the refractory ball 11 to move to the left is then created, and the refractory ball 11 inside the hollow horizontal tube 10 will move to the left as a whole. Then the refractory ball 11 inside the hollow column 9 on the right side will move downward as a whole. Then the refractory ball 11 inside the U-rib 2 of the top plate will move to the right as a whole. This leaves space for the gap 12, which is convenient for the ball pushing mechanism 15 to push the ball again. In this way, all the refractory balls 11 are in motion. This movement of the refractory balls 11 can accelerate the absorption of heat on the one hand, and make the heat absorption of the refractory balls 11 more uniform on the other hand, and also make the outer ring temperature of the steel box girder relatively uniform. The elastic partition 13 is configured such that during the process of the ball-pushing mechanism 15 pushing the refractory ball 11 upward through the through hole 14, the elastic partition 13 deforms. This deformation process simultaneously drives the refractory ball 11 to move, which accelerates the heat absorption of the refractory ball 11, thereby improving the cooling effect. Once the refractory ball 11 passes through the through hole 14, the elastic partition 13, no longer under the pushing force, returns to its original state. This instantaneous return generates a large elastic force on the refractory ball 11, causing the refractory ball 11 on the elastic partition 13 to undergo a large-amplitude bounce. This has the following effects: 1) It accelerates the heat absorption of the refractory ball 11; 2) It accelerates the heat absorption of the refractory ball 11; 1) This bouncing process will cause the refractory ball 11 to come into contact with the inner wall of the top plate 1, further improving the speed and efficiency of heat absorption by the refractory ball 11; 2) This bouncing process will also make it easier for the refractory ball 11 above the through hole 14 to move to the right and get out of the through hole 14, so that the position of the through hole 14 is empty, which will facilitate the smooth progress of the next ball push; 3) Since the top plate 1 directly carries the vehicle, the top plate 1 is prone to deformation due to the pressure of the vehicle coming and going. The up and down bouncing process of the refractory ball 11 is actually an upward knocking force on the top plate 1, and this upward knocking force plays a role in preventing the deformation of the top plate 1 to a certain extent; 4) The elastic partition 13 also plays a certain anti-vibration effect.

[0033] The ball-pushing mechanism 15 includes a protective box 16 fixed to the bottom of the hollow column 9 on the left side. A cylinder 17 is fixed inside the protective box 16. A 7-shaped push plate 19 is fixed to the end of the telescopic rod 18 of the cylinder 17. A lifting channel 20 for the 7-shaped push plate 19 is opened at the bottom of the hollow column 9. This is the specific structure of the ball-pushing mechanism 15. When pushing the ball, only the cylinder 17 needs to be activated. When the cylinder 17 is activated, its telescopic rod 18 extends, causing the 7-shaped push plate 19 to extend. As the pusher plate 19 extends, during this extension process, the horizontal plate of the 7-shaped pusher plate 19 pushes the refractory ball 11 upwards. The vertical plate of the 7-shaped pusher plate 19 is blocked by the refractory ball 11 on its right side, preventing it from rolling to the left and thus preventing it from jamming the telescopic rod 18 and causing the ball-pushing mechanism 15 to malfunction. After the cylinder 17 completes the ball-pushing process, its telescopic rod 18 retracts back to its original position to await the next ball-pushing process. The time interval for the ball-pushing mechanism 15 is set according to actual needs, and this time interval can also be adjusted at any time as needed.

[0034] The height of the gap 12 is 1.5-2 times the diameter of the refractory ball 11. This size of the gap 12 is just right, neither too large to waste space nor too small to be able to push the refractory ball 11.

[0035] The elastic partition 13 is made of rubber, and the through hole 14 is circular with a diameter slightly smaller than that of the fire-resistant ball 14. The elastic partition 13 can be in the form of a rubber band, which provides good elasticity. The through hole 14 facilitates the ball-pushing mechanism 15 to push the top fire-resistant ball 11 of the left hollow column 9 through the through hole 14. The through hole 14 is expanded during the compression of the fire-resistant ball 11 until the top fire-resistant ball 11 is squeezed above the through hole 14. At this time, the through hole 14 will return to its original shape, holding the fire-resistant ball 11 and preventing it from falling down.

[0036] The inner bottom surface of the hollow horizontal tube 10 gradually slopes upward from left to right. This arrangement guides the refractory ball 11 inside the hollow horizontal tube 10, making it easier for the refractory ball 11 inside the hollow horizontal tube 10 to move to the right.

[0037] The elastic partition 13 has an internal cavity 21. The inner wall of the cavity 21 is lined with an isolation layer 22. The space enclosed by the isolation layer 22 is filled with fire-retardant sealant 23. The isolation layer 22 is not fixedly connected to the inner wall of the cavity 21. The isolation layer 22 matches the cavity 21 and is lined within the cavity 21. The space enclosed by the isolation layer 22 is filled with fire-retardant sealant 23. This ensures that the elastic function of the elastic partition 13 is not affected, while also providing fire protection. In the event of a fire, the temperature of the elastic partition 13 will rise and melt, but the fire-retardant sealant 23 inside will not melt. The fire-resistant ball 11 and the fire-retardant sealant 23 will form a double-layer fire barrier, providing excellent fire protection. Once the elastic partition 13 melts, the ball-pushing mechanism 15 will not be able to operate normally, thus triggering an alarm and serving as a fire alarm.

[0038] A layer of fire-resistant adhesive 24 is fixed on the right inner wall of the left hollow column 9, the inner top surface of the hollow horizontal tube 10, and the left inner wall of the right hollow column 9. The fire-resistant adhesive 24 further enhances the fireproofing effect.

[0039] A method for manufacturing a steel box girder, the specific steps are as follows: S1: Produce the top plate 1, top plate U-rib 2, transverse diaphragm 3, bottom plate 4, web plate 6, cantilever arm 7, and hollow column 9 required for steel box girder assembly. When producing the left hollow column 9, first fix the elastic limiting ring 25 inside it.

[0040] S2: Weld the bottom of the base plate 4 to the bottom of the web plate 6; S3: Fix the cantilever arm 7 on the outer surface of the leftmost and rightmost web plates 6; S4: Weld the transverse partition 3 between adjacent web plates; S5: Weld the hollow horizontal tube 11 onto the base plate 4. When welding, first weld the left side plate, right side plate, and top plate of the hollow horizontal tube 11 together, and then weld the three together to the corresponding positions on the base plate 4. This completes the installation of the hollow horizontal tube 11. The front and rear ends of the hollow horizontal tube 11 have openings for welding and connecting with the hollow column 9. In addition, before welding the welded left side plate, right side plate, and top plate to the base plate 4, first weld the corresponding parts of the base plate 4. The inner bottom surface is inclined, gradually sloping downwards from the end away from the ball-pushing mechanism 15 towards the end of the ball-pushing mechanism 15; S6: Install and fix the ball-pushing mechanism 15 on the bottom plate 4; S7: Weld a hollow column 9 onto the hollow horizontal tube 10, and insert an appropriate number of fire-resistant balls 11 through the upper opening of the hollow column 9; S8: Weld the top plate U-rib 2 to the top of the hollow column 9, wherein the bottom of the top plate U-rib 2 has an opening for welding and communication with the top of the hollow column 9; S9: Fix an elastic partition 13 inside the top plate U-rib 2, and place an appropriate number of fire-resistant balls 11 inside it; S10: Weld the top plate 1 to the top plate U-rib 2. The steel box girder of the present invention can be manufactured by this method.

[0041] Working principle: When the steel box girder of this invention is used in a place with large temperature differences between day and night, when the outside temperature is too high during the day, causing the temperature of the top plate 1, bottom plate 4, and hollow column 9 to rise, the fire-resistant ball 11 can absorb the heat from the top plate 1, bottom plate 4, and hollow column 9 in a timely manner and store the heat inside the fire-resistant ball 11. This effectively cools the top plate 1, bottom plate 4, and hollow column 9, preventing the temperature of the steel box girder from rising continuously with the increase of the outside temperature. Once the temperature of the top plate 1, bottom plate 4, and hollow column 9 can be reduced in time and absorbed by the fire-resistant ball 11, the heat will not be transferred to the interior of the steel box girder. This ensures the overall temperature stability of the steel box girder and prevents it from rising with the increase of the outside temperature, thus effectively preventing the steel box girder from expanding due to temperature rise. When the outside temperature drops at night, causing the temperature of the top plate 1, bottom plate 4, and hollow column 9 to decrease, the temperature of the refractory ball 11 is higher than that of the top plate 1, bottom plate 4, and hollow column 9. At this time, the heat accumulated by the refractory ball 11 during the day will be released to the outside, which will play a timely role in raising the temperature of the top plate 1, bottom plate 4, and hollow column 9, preventing them from decreasing with the decrease of the outside temperature. This effectively prevents the steel box girder from shrinking due to the decrease in temperature. Therefore, the temperature regulation mechanism 8 effectively regulates the temperature of the steel box girder, avoids the impact of sudden changes in the outside temperature on the steel box girder, and effectively solves the problem of thermal expansion and contraction of the steel box girder. The specific working principle of the temperature regulation mechanism 8 is as follows: When the ball pushing mechanism 15 is activated, it pushes the refractory ball 11 inside the hollow column 9 on the left upwards. The bottommost refractory ball 11 is pushed above the elastic limiting ring 25, and the topmost refractory ball 11 passes through the through hole 14 and reaches above the elastic partition 13. Then the ball pushing mechanism 15 returns to its original position. During the return process, the refractory ball 11 above it is stopped from moving downwards by the elastic limiting ring 25. After the ball pushing mechanism 15 returns to its original position, a hollow horizontal space is left between the ball pushing mechanism 15 and the elastic limiting ring 25. The space for the refractory balls 11 inside the tube 10 to move to the left is then created. After that, the refractory balls 11 inside the hollow horizontal tube 10 will move to the left as a whole. Then, the refractory balls 11 inside the hollow column 9 on the right side will move downward as a whole. After that, the refractory balls 11 inside the top plate U-rib 2 will move to the right as a whole. This leaves space for the gap 12, which is convenient for the ball pushing mechanism 15 to push the balls again. In this way, all the refractory balls 11 are in motion. This movement of the refractory balls 11 can accelerate the absorption of heat on the one hand, and make the heat absorption of the refractory balls 11 more uniform on the other hand, and also make the outer ring temperature of the steel box girder relatively uniform.The elastic partition 13 is configured such that during the process of the ball-pushing mechanism 15 pushing the refractory ball 11 upward through the through hole 14, the elastic partition 13 deforms. This deformation process simultaneously drives the refractory ball 11 to move, which accelerates the heat absorption of the refractory ball 11, thereby improving the cooling effect. Once the refractory ball 11 passes through the through hole 14, the elastic partition 13, no longer under the pushing force, returns to its original state. This instantaneous return generates a large elastic force on the refractory ball 11, causing the refractory ball 11 on the elastic partition 13 to undergo a large-amplitude bounce. This has the following effects: 1) It accelerates the heat absorption of the refractory ball 11; 2) It accelerates the heat absorption of the refractory ball 11; 1) This bouncing process will cause the refractory ball 11 to come into contact with the inner wall of the top plate 1, further improving the speed and efficiency of heat absorption by the refractory ball 11; 2) This bouncing process will also make it easier for the refractory ball 11 above the through hole 14 to move to the right and get out of the through hole 14, so that the position of the through hole 14 is empty, which will facilitate the smooth progress of the next ball push; 3) Since the top plate 1 directly carries the vehicle, the top plate 1 is prone to deformation due to the pressure of the vehicle coming and going. The up and down bouncing process of the refractory ball 11 is actually an upward knocking force on the top plate 1, and this upward knocking force plays a role in preventing the deformation of the top plate 1 to a certain extent; 4) The elastic partition 13 also plays a certain anti-vibration effect.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A steel box girder, characterized in that, Includes a top plate (1), the top of several top plate U-ribs (2) are fixed on the bottom surface of the top plate (1), the bottom of the top plate U-ribs (2) are fixed on the top of several transverse partitions (3), the bottom of the transverse partitions (3) are fixed on the bottom plate (4), several sets of web plate groups (5) are fixed on the bottom plate (4), the web plate group (5) is composed of two web plates (6) in the shape of an inverted V, the bottom of the web plate (6) is fixed on the bottom plate (4), and the web plate (6) separates the left and right adjacent transverse partitions (3), several cantilever arms (7) are provided at both ends of the transverse partitions (3), and several temperature adjustment mechanisms (8) are provided between the top plate (1) and the bottom plate (4); The temperature regulating mechanism (8) includes the top plate U-rib (2), which is hollow and connected to the upper end of a hollow column (9) near both ends. A hollow horizontal tube (10) is connected between the lower ends of the two hollow columns (9). The hollow horizontal tube (10), the hollow column (9), and the top plate U-rib (2) are filled with fire-resistant balls (11), which play a role in regulating the temperature. The refractory balls (11) in the top plate U-rib (2) and the hollow horizontal tube (10) are arranged in a horizontal row, and the refractory balls (11) in the two hollow columns (9) are arranged in a vertical row. A gap (12) is left between the top of the uppermost refractory ball (11) in the hollow column (9) on the left and the inner top surface of the hollow horizontal tube (10). An elastic partition (13) is provided in the top plate U-rib (2). The left end of the plate (13) is fixed to the left inner wall of the top plate U rib (2) on the left side, and its right end is fixed to the right end of the inner bottom surface of the top plate U rib (2). The elastic partition (13) gradually slopes downward from left to right, and a through hole (14) for the fire-resistant ball (11) to pass through is opened at its left end. A ball pushing mechanism (15) is provided at the bottom of the hollow column (9) on the left side, and an elastic limiting ring (25) is provided inside the hollow column (9) on the left side. The ball-pushing mechanism (15) includes a protective box (16) fixed to the bottom of the hollow column (9) on the left side. A cylinder (17) is fixed inside the protective box (16). A 7-shaped push plate (19) is fixed to the end of the telescopic rod (18) of the cylinder (17). A lifting channel (20) for the 7-shaped push plate (19) is opened at the bottom of the hollow column (9). The inner bottom surface of the hollow horizontal tube (10) gradually slopes upward from left to right.

2. A steel box girder according to claim 1, characterized in that, The height of the gap (12) is 1.5-2 times the diameter of the refractory ball (11).

3. A steel box girder according to claim 1, characterized in that, The elastic partition (13) is made of rubber, and the through hole (14) is circular with a diameter smaller than that of the fire-resistant ball (11).

4. A steel box girder according to claim 3, characterized in that, The elastic partition (13) has a cavity (21) inside, and the inner wall of the cavity (21) is lined with an isolation layer (22). The space enclosed by the isolation layer (22) is filled with fireproof sealant (23).

5. A steel box girder according to claim 4, characterized in that, A layer of fire-resistant adhesive (24) is fixed on the right inner wall of the hollow column (9) on the left, the inner top surface of the hollow horizontal tube (10), and the left inner wall of the hollow column (9) on the right.

6. A method for manufacturing a steel box girder, characterized in that, It relates to the steel box girder as described in any one of claims 1-5, and the specific steps are as follows: S1: The top plate (1), top plate U-rib (2), diaphragm (3), bottom plate (4), web plate (6), cantilever (7), and hollow column (9) required for the assembly of steel box girder. When producing the left hollow column (9), first fix the elastic limiting ring (25) inside it. S2: Weld the bottom of the base plate (4) to the bottom of the web plate (6) to fix it; S3: Fix the boom (7) on the outer surface of the leftmost and rightmost web (6). S4: Weld and fix transverse diaphragms between adjacent webs (3); S5: Weld hollow horizontal tubes (10) onto the base plate (4); S6: Install a fixed ball-pushing mechanism (15) on the base plate (4); S7: Weld a hollow column (9) onto the hollow horizontal tube (10), and insert an appropriate number of fire-resistant balls (11) through the upper opening of the hollow column (9). S8: Weld the top plate U-rib (2) to the top of the hollow column (9), wherein the bottom of the top plate U-rib (2) has an opening for welding to the top of the hollow column (9); S9: Fix an elastic partition (13) inside the top plate U-rib (2) and place an appropriate number of fire-resistant balls (11) inside it. S10: Weld the top plate (1) to the top plate U-rib (2).

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