Modularized pier anti-collision energy-absorbing device

Abstract

The invention discloses a modularized bridge pier anti-collision energy-absorbing device which comprises energy-absorbing modules and rubber balls, the two energy-absorbing modules are arranged side by side, the rubber balls are connected between the two energy-absorbing modules, and a first layer of foamed aluminum, a polyurethane layer, a second layer of foamed aluminum and a third layer of foamed aluminum in each energy-absorbing module are arranged according to the length dimension proportion of 3: 5: 2: 1. And the device can fully utilize the characteristics of various materials. The foamed aluminum is light and has good energy absorption performance, the polyurethane layer is high in toughness, impact energy can be effectively absorbed and dispersed in the modes of material deformation, friction and the like when the bridge pier is impacted, impact force on the bridge pier is greatly reduced, the bridge pier structure safety is protected, the multiple rubber balls are arranged in the length direction of the first outer side steel plate at intervals, the outer diameter size is gradually changed, and the service life is prolonged. The overall flexibility of the device is enhanced, the device can better adapt to collision of different angles and strengths, energy can be further absorbed through deformation of the rubber balls, and the anti-collision reliability and practicability of the pier are overall improved.

Description

Technical Field

[0001] The present application relates to the technical field of bridge pier anti-collision energy absorption devices, and in particular to a modular bridge pier anti-collision energy absorption device. Background Art

[0002] In the field of bridge construction, pier anti-collision has always been a key link in ensuring bridge safety. Existing pier anti-collision technology has many shortcomings when dealing with complex collision situations.

[0003] Early anti-collision measures for bridge piers were relatively simple, mostly using direct protection structures, such as installing ordinary protective plates on the surface of bridge piers. Such protective plates are usually made of a single material, have limited anti-collision capabilities, and can only cope with smaller impact forces. When hit by a larger ship, the protective plates are easily damaged and cannot effectively protect the bridge piers. Moreover, this protection method lacks an energy absorption mechanism, and almost all the energy generated by the impact is borne by the bridge piers themselves, which greatly increases the risk of damage to the bridge piers, which will affect the overall structural stability and service life of the bridge in the long run.

[0004] With the development of technology, some anti-collision devices with energy absorption functions have emerged. For example, some devices use rubber materials as energy absorption media and use the elasticity of rubber to buffer the impact force. However, the energy absorption effect of these devices is limited by the characteristics of rubber materials. For the impact of high-speed and large-mass objects, the energy absorption efficiency is not ideal. In addition, the existing energy absorption devices often have a single structure, which is difficult to flexibly adjust and optimize according to different pier shapes and actual use environments, and have poor versatility. Moreover, most devices lack the function of real-time monitoring of impact force, and cannot obtain impact data in time to evaluate the safety status of the piers, which is not conducive to the effective maintenance and management of bridges. Summary of the invention

[0005] In an exemplary embodiment of the present application, a modular bridge pier anti-collision energy absorption device is provided to effectively improve the anti-collision performance of the bridge.

[0006] The present application provides a modular bridge pier anti-collision energy absorption device, which includes an energy absorption module and a rubber ball, wherein two energy absorption modules are arranged side by side and the rubber ball is connected between the two energy absorption modules; The energy absorption module includes a first outer steel plate, a first layer of foam aluminum, a polyurethane layer, a second layer of foam aluminum, a connecting spring, a third layer of foam aluminum, a pressure sensor, and a second outer steel plate; A first accommodating space is formed inside the first outer steel plate, and the first accommodating space is filled with the first layer of foamed aluminum, the polyurethane layer, and the second layer of foamed aluminum. The first layer of foamed aluminum, the polyurethane layer, and the second layer of foamed aluminum are arranged at intervals along the length direction of the first outer steel plate, and the polyurethane layer is located between the first layer of foamed aluminum and the second layer of foamed aluminum. A second accommodation space is formed inside the second outer steel plate, and the third layer of aluminum foam is filled and arranged in the second accommodation space; One end of the second layer of aluminum foam is arranged inside the first outer steel plate and is connected to the second outer steel plate, and the second outer steel plate and the first outer steel plate are connected by the connecting spring; A plurality of the rubber balls are arranged at intervals along the length direction of the first outer steel plate, and both ends of the rubber balls in the height direction are respectively connected to the energy absorption module; The ratio of the length dimensions of the first layer of aluminum foam, the polyurethane layer, the second layer of aluminum foam, and the third layer of aluminum foam along the length direction of the first outer steel plate is: 3:5:2:1.

[0007] Further, the telescopic direction of the connecting spring is the same as the length direction of the first outer steel plate.

[0008] Further, the outer diameter dimensions of the plurality of rubber balls gradually decrease in the direction from the first layer of aluminum foam to the second layer of aluminum foam.

[0009] Further, a pressure sensor is arranged on the second outer steel plate.

[0010] Further, the rubber balls are respectively connected to the first outer steel plates of two side-by-side arranged energy absorption modules.

[0011] Further, both ends of the rubber ball are respectively connected to the first outer steel plate through connecting ropes.

[0012] Further, the plurality of rubber balls are arranged at equal intervals along the length direction of the first outer steel plate.

[0013] Further, both the first outer steel plate and the second outer steel plate are rectangular parallelepipeds.

[0014] Further, the height dimension of the first outer steel plate is the same as the height dimension of the second outer steel plate.

[0015] The embodiments of the present application have the following beneficial effects: In the energy absorption module, the first layer of aluminum foam, the polyurethane layer, the second layer of aluminum foam, and the third layer of aluminum foam are arranged according to the length dimension ratio of 3:5:2:1. This scientific ratio enables the device to make full use of the characteristics of each material. Aluminum foam is lightweight and has good energy absorption properties, and the polyurethane layer has strong toughness. They cooperate with each other. When suffering an impact, they can effectively absorb and disperse the impact energy through the deformation, friction, etc. of the materials, greatly reducing the impact force on the bridge pier and protecting the structural safety of the bridge pier. The telescopic design of the connecting spring in the same length direction as the first outer steel plate further enhances the energy absorption effect. It can provide buffering at the moment of impact, extend the impact action time, and reduce the impact peak force.

[0016] A plurality of rubber balls are arranged at intervals along the length direction of the first outer steel plate, and the outer diameter size changes gradually. This not only enhances the overall flexibility of the device, enabling it to better adapt to impacts at different angles and intensities, but also can further absorb energy through the deformation of the rubber balls.

[0017] A pressure sensor is arranged on the second outer steel plate, which can monitor the impact pressure data in real time, providing an important basis for bridge maintenance and safety assessment. In addition, the modular design of the device is convenient for installation, disassembly, and replacement, improving the usability and maintenance efficiency, and overall enhancing the reliability and practicality of the bridge pier anti-collision. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 The structural schematic diagram of a modular bridge pier anti-collision energy absorption device provided by the embodiments of the present application is exemplarily shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application.

[0021] To further illustrate the technical solutions provided by the embodiments of the present application, the following will provide a detailed description thereof in combination with the drawings and specific implementation manners. Although the embodiments of the present application provide the method operation steps as shown in the following embodiments or drawings, more or fewer operation steps may be included in the method based on routine or non-creative labor. In the steps where there is no necessary causal relationship logically, the execution order of these steps is not limited to the execution order provided by the embodiments of the present application.

[0022] refer to Figure 1 As shown, the present application provides a modular bridge pier anti-collision energy absorption device, which includes an energy absorption module and a rubber ball 8, wherein two energy absorption modules are arranged side by side and the rubber ball 8 is connected between the two energy absorption modules.

[0023] The energy absorption module includes a first outer steel plate 1 , a first layer of foamed aluminum 2 , a polyurethane layer 3 , a second layer of foamed aluminum 4 , a connecting spring 5 , a third layer of foamed aluminum 6 , a pressure sensor 7 and a second outer steel plate 9 .

[0024] A first accommodating space is formed inside the first outer steel plate 1, and the first accommodating space is filled with a first layer of foam aluminum 2, a polyurethane layer 3 and a second layer of foam aluminum 4. The first layer of foam aluminum 2, the polyurethane layer 3 and the second layer of foam aluminum 4 are arranged at intervals along the length direction of the first outer steel plate 1, and the polyurethane layer 3 is located between the first layer of foam aluminum 2 and the second layer of foam aluminum 4.

[0025] A second accommodating space is formed inside the second outer steel plate 9 , and a third layer of foam aluminum 6 is filled in the second accommodating space.

[0026] The first outer steel plate 1 serves as the initial bearing interface of the impact load. On the one hand, it constrains the deformation direction of the internal energy-absorbing material through the rigid shell, ensuring that the impact energy is transmitted to the internal functional layer in an orderly manner along a preset path, thereby avoiding energy dissipation due to disordered deformation of the material; on the other hand, it provides structural support for modular components such as the external rubber ball 8 to achieve the overall assembly integration of the device.

[0027] The first layer of foam aluminum 2 arranged inside it serves as a direct stress-bearing layer. By utilizing the porous compression characteristics of the material, plastic deformation occurs preferentially when subjected to collision loads, and the initial impact peak is quickly attenuated through cell collapse and friction effects. At the same time, stress buffering is provided for the high elastic deformation of the rear polyurethane layer 3, thereby optimizing the mechanical response conditions of subsequent material layers.

[0028] The second outer steel plate 9 is responsible for energy regulation and system coordination functions. The third layer of foam aluminum 6 filled inside it forms an elastic termination interface with the connecting spring 5: the thin layer design of the third layer of foam aluminum 6 can not only limit the excessive compression of the front energy-absorbing material, but also form a flexible rebound mechanism together with the spring, which converts the residual energy into elastic potential energy in the later stage of the impact and releases it slowly.

[0029] This double steel plate structure maintains the stability of the overall structure of the device through the alternating layout of rigid and flexible areas, and realizes the timed dissipation of impact energy through the hierarchical design of the first steel plate (rigid load-bearing) - the middle functional layer (flexible energy dissipation) - the second steel plate (elastic regulation).

[0030] The first layer of aluminum foam 2 in the first outer steel plate 1 is set to be at the force-bearing position or to bear the force, mainly based on the dual advantages of its material properties and structural positioning. As the outermost energy-absorbing layer, its porous structure can quickly absorb and disperse the impact kinetic energy through large-scale plastic deformation at the initial stage of collision, reducing the strain rate threshold borne by the rear polyurethane layer 3, thereby avoiding the molecular chain breakage of high-elastic materials due to instantaneous overload.

[0031] At the same time, the compression behavior of this layer of aluminum foam can form a progressive stress platform, effectively extending the action time window of the impact load and providing a stable mechanical transmission environment for the subsequent energy dissipation levels. This hierarchical force-bearing design not only optimizes the functional matching of each material layer but also improves the structural reliability of the device under extreme impact conditions through the strategy of preferentially consuming plastic materials.

[0032] The ratio of the length dimensions of the first layer of aluminum foam 2, polyurethane layer 3, second layer of aluminum foam 4, and third layer of aluminum foam 6 along the length direction of the first outer steel plate 1 is: 3:5:2:1.

[0033] By forming a time difference in the compression deformation of materials through different length configurations: the first layer of aluminum foam 2 (accounting for 3) at the front end, as a rigid buffer layer, uses its high porosity characteristics to quickly disperse the initial impact kinetic energy.

[0034] The polyurethane layer 3 with the largest proportion in the middle section (accounting for 5) serves as the core energy-consuming medium. Relying on its super-elastic deformation ability, it realizes energy conversion through viscous flow and molecular chain friction when the structure undergoes large displacements.

[0035] The second layer of aluminum foam 4 (accounting for 2) and the third layer of aluminum foam 6 (accounting for 1) at the end form a decreasing stiffness transition, which not only serves as a physical constraint layer for the previous deformation but also forms an elastic recovery system with the connecting spring 5 to achieve the flexible release of residual energy.

[0036] This stiffness layout that gradually decreases from the outside to the inside essentially forms a three-stage energy processing mechanism of "rigid buffer - viscoelastic dissipation - elastic feedback".

[0037] By rapidly attenuating the peak stress through the front-section aluminum foam, continuously consuming energy through the middle-section polyurethane to extend the action time, and suppressing stress rebound through the synergistic action of the end thin layer and the spring, a gradient transition of wave impedance is formed.

[0038] The primary-secondary ratio of polyurethane to aluminum foam of 5:3 optimizes the material utilization rate, and the 1:2 thin-layer design at the end reserves elastic deformation space for the spring system. This orderly interlayer mechanical response mechanism not only ensures that each material layer plays a role within its optimal working range but also realizes the effective conversion of impact energy through the coordinated deformation of the overall structure, while significantly enhancing the structural stability of the device under repeated impact conditions.

[0039] One end of the second layer of aluminum foam 4 is arranged inside the first outer steel plate 1 and is connected to the second outer steel plate 9, and the second outer steel plate 9 is connected to the first outer steel plate 1 through a connecting spring 5.

[0040] Both the first outer steel plate 1 and the second outer steel plate 9 are cuboid-shaped. The height dimension of the first outer steel plate 1 is the same as the height dimension of the second outer steel plate 9.

[0041] A plurality of rubber balls 8 are arranged at intervals along the length direction of the first outer steel plate 1, and both ends of the rubber balls 8 in the height direction are respectively connected to the energy absorption module.

[0042] The telescopic direction of the connecting spring 5 is the same as the length direction of the first outer steel plate 1.

[0043] The outer diameter dimensions of the plurality of rubber balls 8 gradually decrease in the direction from the first layer of aluminum foam 2 to the second layer of aluminum foam 4.

[0044] The length dimension ratio of the first layer of aluminum foam 2, the polyurethane layer 3, the second layer of aluminum foam 4 and the third layer of aluminum foam 6 is 3:5:2:1, which determines the role and participation degree of each layer of material in the energy absorption process. The polyurethane layer 3 has the largest proportion and undertakes the main energy absorption task, while the aluminum foam assists in dispersing and absorbing energy.

[0045] The outer diameter of the rubber ball 8 gradually decreases from the first layer of aluminum foam 2 to the second layer of aluminum foam 4, echoing the length dimension ratio of the materials. The outer diameter of the rubber ball 8 is large near the first layer of aluminum foam 2, which can withstand a large impact force at the initial stage of impact and provide a preliminary buffer, and cooperate with the relatively long first layer of aluminum foam 2 to initially absorb and disperse the energy.

[0046] As the impact energy is transmitted, the rubber balls 8 with gradually decreasing outer diameters can adapt to the energy absorption characteristics of the subsequent layers of materials. When the polyurethane layer 3 plays the main energy absorption role, the rubber balls 8 with smaller outer diameters can more accurately transmit the energy to the corresponding material layer, realizing the orderly transmission and efficient absorption of energy.

[0047] In terms of optimizing energy distribution, such a design enables the entire device to reasonably distribute energy according to the material characteristics at different positions. The rubber balls 8 with different outer diameters are like energy regulating valves, and according to the length and function of each material layer, accurately adjust the size of the transmitted energy, avoid excessive local energy concentration, ensure that each layer of material can fully play its energy absorption role, thereby improving the overall anti-collision and energy absorption performance and protecting the bridge pier more effectively.

[0048] The high stiffness characteristics of the large balls in the front section suppress the sudden structural displacement caused by the initial impact, and the flexible characteristics of the small balls in the rear section provide a buffer margin for continuous deformation, enabling the overall structure to still maintain controllable deformation under severe impact.

[0049] The rubber ball 8 serves as a flexible connector across modules, forming distributed energy-dissipating nodes between the double energy-absorbing modules. When subjected to oblique or eccentric impacts, the rubber ball 8 actively adjusts the load transfer path through asymmetric compression deformation: the larger-diameter sphere is arranged in the strong stress area near the first layer of aluminum foam 2.

[0050] Utilizing its high volume compression ratio, it preferentially dissipates the impact kinetic energy; the tapered diameter design adapts to the decreasing stress intensity at the rear, forming an energy gradient that matches the level of the energy-absorbing module. This spatial matching mechanism enables the impact energy to be distributed as needed in three-dimensional space, effectively suppressing the phenomenon of local overload.

[0051] The rubber ball 8 enhances the energy conversion efficiency through the dual mechanisms of viscoelastic hysteresis effect and internal friction. During the dynamic impact process, the stretching and retracting movement of the rubber molecular chains generates hysteretic heat, while the periodic compression and expansion of the internal cavity of the sphere trigger turbulent friction energy dissipation.

[0052] The flexible restraint of the connecting rope allows each rubber ball 8 to have a certain degree of swing amplitude, guiding the redistribution of the load through the coordinated deflection of the sphere cluster during non-normal impacts.

[0053] The rubber ball 8 is respectively connected to the first outer steel plate 1 of two side-by-side arranged energy-absorbing modules. The two ends of the rubber ball 8 are respectively connected to the first outer steel plate 1 through connecting ropes.

[0054] The rubber ball 8 is connected between two steel plates. It can not only buffer part of the impact force with its own elasticity when being impacted, but also connect the two steel plates into a whole, enhancing the integrity and stability of the device. When an external force impacts, the rubber ball 8 can deform to a certain extent in the height direction, dispersing and absorbing part of the energy, reducing the impact force transmitted to the steel plate, and protecting the integrity of the steel plate and the internal material structure.

[0055] The material in the first outer steel plate 1 is arranged along its length direction and is perpendicular to the connection direction of the rubber ball 8 in the height direction. This design helps to optimize the energy-absorbing path. When being impacted, the impact force is transmitted to the first outer steel plate 1 through the rubber ball 8. Due to the material being distributed along the length direction, the impact force can be dispersed along the arrangement direction of the material. Different materials (such as the first layer of aluminum foam 2, polyurethane layer 3, and the second layer of aluminum foam 4) absorb and consume energy in sequence and proportion along the length direction, forming a multi-level and multi-stage energy-absorbing process. This vertically arranged method avoids the concentration of energy in a certain direction or a certain material layer, improves the efficiency and uniformity of energy absorption, enables the entire device to more effectively protect the bridge pier when facing impacts, and enhances the anti-collision energy-absorbing effect.

[0056] A plurality of rubber balls 8 are arranged at equal intervals along the length direction of the first outer steel plate 1. The equal interval arrangement enables the rubber balls 8 to evenly distribute the impact force on the first outer steel plate 1 when facing an impact. When an external object impacts the device, each rubber ball 8 can receive and transmit the impact force at the same interval distance, avoiding the situation of excessive local stress.

[0057] If the rubber balls 8 are unevenly distributed, it may cause the impact force borne by some areas to be much greater than that of other areas, resulting in serious local damage to the device, while other parts fail to fully play their roles. By arranging them at equal intervals, the entire first outer steel plate 1 can be evenly stressed, giving full play to its structural strength and protective performance, effectively protecting the internal energy-absorbing material, and ensuring the overall stable operation of the energy-absorbing module.

[0058] A pressure sensor 7 is arranged on the second outer steel plate 9. By arranging the pressure sensor 7 on the second outer steel plate 9, the impact pressure data can be monitored in real time, providing an important basis for bridge maintenance and safety assessment.

[0059] In the energy-absorbing module, the first layer of aluminum foam 2, polyurethane layer 3, second layer of aluminum foam 4, and third layer of aluminum foam 6 are arranged according to the length dimension ratio of 3:5:2:1. This scientific ratio enables the device to make full use of the characteristics of each material. Aluminum foam is lightweight and has good energy-absorbing properties, and the polyurethane layer 3 has strong toughness. They cooperate with each other and can effectively absorb and disperse the impact energy through material deformation, friction, etc. when suffering an impact, greatly reducing the impact force on the bridge pier and protecting the structural safety of the bridge pier. The telescopic design of the connecting spring 5 in the same length direction as the first outer steel plate 1 further enhances the energy-absorbing effect. It can provide buffering at the moment of impact, extend the impact action time, and reduce the impact peak force.

[0060] A plurality of rubber balls 8 are arranged at intervals along the length direction of the first outer steel plate 1, and the outer diameter size changes gradually. This not only enhances the overall flexibility of the device, enabling it to better adapt to impacts at different angles and intensities, but also can further absorb energy through the deformation of the rubber balls 8.

[0061] This application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to this application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for realizing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0062] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to work in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the functions specified in one or more of the processes Figure 1 or more processes and / or blocks Figure 1 or more blocks.

[0063] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, such that a series of operation steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more of the processes Figure 1 or more processes and / or blocks Figure 1 or more blocks.

[0064] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to cover these modifications and variations.

Claims

1. A modular bridge pier anti-collision energy absorption device, characterized in that: It comprises an energy absorbing module and a rubber ball, wherein two energy absorbing modules are arranged side by side and the rubber ball is connected between the two energy absorbing modules; The energy absorption module includes a first outer steel plate, a first layer of foam aluminum, a polyurethane layer, a second layer of foam aluminum, a connecting spring, a third layer of foam aluminum, a pressure sensor, and a second outer steel plate; A first accommodating space is formed inside the first outer steel plate, and the first accommodating space is filled with the first layer of foamed aluminum, the polyurethane layer, and the second layer of foamed aluminum. The first layer of foamed aluminum, the polyurethane layer, and the second layer of foamed aluminum are arranged at intervals along the length direction of the first outer steel plate, and the polyurethane layer is located between the first layer of foamed aluminum and the second layer of foamed aluminum. A second accommodating space is formed inside the second outer steel plate, and the third layer of foam aluminum is filled in the second accommodating space; One end of the second layer of foamed aluminum is arranged inside the first outer steel plate and is connected to the second outer steel plate, and the second outer steel plate is connected to the first outer steel plate via the connecting spring; A plurality of the rubber balls are arranged at intervals along the length direction of the first outer steel plate, and both ends of the rubber balls in the height direction are respectively connected to the energy absorption modules; The ratio of the length dimensions of the first layer of foam aluminum, the polyurethane layer, the second layer of foam aluminum and the third layer of foam aluminum along the length direction of the first outer steel plate is: 3:5:2:

1.

2. The modular bridge pier anti-collision energy absorption device according to claim 1 is characterized in that: The expansion and contraction direction of the connecting spring is the same as the length direction of the first outer steel plate.

3. The modular bridge pier anti-collision energy absorption device according to claim 2 is characterized in that: The outer diameters of the plurality of rubber balls gradually decrease in a direction from the first layer of foam aluminum to the second layer of foam aluminum.

4. The modular bridge pier anti-collision energy absorption device according to claim 3 is characterized in that: The pressure sensor is arranged on the second outer steel plate.

5. The modular bridge pier anti-collision energy absorption device according to claim 4 is characterized in that: The rubber balls are respectively connected to the first outer steel plates of the two energy absorbing modules arranged side by side.

6. The modular bridge pier anti-collision energy absorption device according to claim 5 is characterized in that: Two ends of the rubber ball are connected to the first outer steel plate through connecting ropes respectively.

7. The modular bridge pier anti-collision energy absorption device according to claim 6 is characterized in that: The plurality of rubber balls are arranged at equal intervals along the length direction of the first outer steel plate.

8. The modular bridge pier anti-collision energy absorption device according to claim 7 is characterized in that: The first outer steel plate and the second outer steel plate are both in a rectangular parallelepiped shape.

9. The modular bridge pier anti-collision energy absorption device according to claim 8, characterized in that: The height dimension of the first outer steel plate is the same as the height dimension of the second outer steel plate.

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