A method for designing a modular guardrail and the modular guardrail itself.

Abstract

This invention relates to the technical field of road protection, and particularly to a method for designing a modular guardrail and the modular guardrail itself. The method for designing a modular guardrail includes the following steps: determining the design protection level and the vehicle type to be protected; determining the maximum deformation control index VInmax of the guardrail based on the width of the guardrail surface and the width of the obstacle; determining the minimum distance Hcmin from the top surface of the concrete base to the road surface; determining the minimum distance Htmin from the top surface of the modular guardrail to the road surface; constructing the objective function VIn(X) = F(Hc, Ht, Stc, Stp, Lp, Stb, San, N), and performing finite element simulation analysis of the modular guardrail colliding with the vehicle type to be protected; selecting the case with the least amount of upper metal beam-column structure among the results where VIn(X) ≤ VInmax, and determining the design parameters based on the results corresponding to this case; selecting concrete of corresponding strength based on the results determined by S3, calculating the bearing capacity of the concrete base, and then reinforcing it to complete the design of the modular guardrail.

Description

Technical Field

[0001] This invention relates to the technical field of road protection, and in particular to a method for designing a modular guardrail and the modular guardrail itself. Background Technology

[0002] The modular guardrail consists of a lower concrete base 2 and an upper metal beam-column structure 1, as shown in the attached instruction manual. Figure 1 As shown. The upper metal beam-column structure 1 includes a crossbeam 101 and a column 102. The combined guardrail has functions such as protection, aesthetics, transparency, and barrier, and is widely used in bridge sections.

[0003] However, when there are tall obstacles such as signposts, gantry posts, and light poles on the outside of the modular guardrail and protection is required, the deformation control index of the existing modular guardrail does not meet the standard requirements and cannot be applied. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies where the deformation control index of existing combined guardrails does not meet standard requirements when there are tall obstacles such as sign posts, gate posts, and light poles on the outside of the combined guardrail and protection is required. This invention provides a method for designing combined guardrails and a combined guardrail.

[0005] In a first aspect, the present invention provides a method for designing a modular guardrail, comprising the following steps:

[0006] S1. Determine the design protection level and the design protection vehicle type based on the usage scenario of the combined guardrail; determine the maximum deformation control index VInmax of the guardrail based on the width of the guardrail surface and the width of the obstacle; S2. Based on the typical wheel radius of the designed protective vehicle, determine the minimum distance Hcmin from the top surface of the concrete base to the road surface; based on the typical height Htci of the main structural frame of the designed protective vehicle, determine the minimum distance Htmin from the top surface of the combined guardrail to the road surface. S3. Construct the objective function VIn(X) = F(Hc, Ht, Stc, Stp, Lp, Stb, San, N), where VIn is the guardrail deformation control index, Hc is the height of the concrete base, Ht is the height of the composite guardrail, Stc is the form of the concrete base, Stp is the cross-sectional form of the column, Lp is the column spacing, Stb is the cross-sectional form of the beam, San is the arrangement of the beam, and N is the number of beams. Perform finite element simulation analysis on the design of the composite guardrail to protect against vehicle collisions. Select the case with the least amount of upper metal beam-column structure among the results of VIn(X) ≤ VInmax, and determine Hc, Ht, Stc, Stp, Lp, Stb, San, and N based on the results corresponding to this case. S4. Based on the Stc determined in S3, select concrete of the corresponding strength, calculate the bearing capacity of the concrete base, and then reinforce it to complete the design of the composite guardrail.

[0007] Obstacles include marker posts, gantry posts, light poles, and other objects installed on the outer side of the modular guardrail. Design protection levels include: HA, HB (Extra High Protection Level), SS (High Protection Level), SA (Relatively High Protection Level), and SB (General Protection Level). Designed protection vehicle types include: small passenger cars (1.5t), large passenger cars (18t), extra-large passenger cars (25t), large freight cars (33t), and saddle-type trains (55t).

[0008] When the height of the concrete base is greater than or equal to the radius of the vehicle, it can effectively reduce the uneven force on the wheels during a collision, making the vehicle guidance smoother. The main structural frame of the protected vehicle is determined according to the type of vehicle being designed. The objective function Vin(X) is the value of the guardrail deformation control index Vin, calculated from the subsequent parameters. When Vin(X) ≤ Vinmax, the values ​​of Hc, Ht, Lp, and N, as well as the forms of Ste, Stp, and San, are determined with the minimum amount of upper metal beam-column structure used. Minimizing the amount of upper metal beam-column structure helps to save costs, enhance durability, and improve structural stability. This application provides a design method for a composite guardrail, providing a basis for the design of composite guardrails.

[0009] Preferably, when there is more than one type of protected vehicle, the maximum value of the typical wheel radius of different types is taken as Hcmin.

[0010] Preferably, when obtaining typical wheel radius values, the selected wheel radii are first sorted from smallest to largest and a cumulative percentage curve is plotted. Then, the value at 85% is taken as the typical wheel radius value.

[0011] Preferably, when calculating the bearing capacity of the concrete base in S4, the collision load of the concrete base is taken as the maximum value between the standard value of the lateral collision load of the bridge railing and the peak value of the collision force of the bridge railing extracted by simulation analysis.

[0012] Preferably, the peak impact force of the bridge railing extracted through simulation analysis includes the following steps: A1. Obtain the lateral collision load curve of the designed protective vehicle based on the time history curve of the collision force between the designed protective vehicle and the guardrail. A2. Perform moving average processing on the lateral collision load curve and obtain the peak value of the bridge railing collision force.

[0013] Preferably, after S4, based on the parameters determined in S3, a finite element model of the combined guardrail and the designed protective vehicle model is established in the modeling platform and analyzed. If the design requirements of the combined guardrail are not met, S3 and S4 are repeated until the design requirements of the combined guardrail are met.

[0014] Preferably, when establishing a finite element model in the modeling platform, the anchor bolt model includes a first unit and a second unit. The first unit is set inside the concrete base and is modeled in the form of a beam element. The first unit is used for coupling analysis with the concrete base. The second unit is set on the upper part of the concrete base and is modeled in the form of a beam element enclosing a shell element. The second unit is used for contact analysis with the upper metal beam-column structure.

[0015] Preferably, in S2, when the designed protected vehicle is a passenger car, the typical height value Htci of the main structural frame is taken as the typical height value of the vehicle frame; when the designed protected vehicle is a freight car, the typical height value Htci of the main structural frame is taken as the typical height value of the cargo box floor; when the designed protected vehicle is both a passenger car and a freight car, the typical height value Htci of the main structural frame is taken as the larger of the typical height value of the vehicle frame and the typical height value of the cargo box floor.

[0016] Preferably, when determining the value or form of a certain parameter in S3, it is determined by the method of controlling variables.

[0017] In a second aspect, the present invention provides a modular guardrail, which is designed by the method described above for designing a modular guardrail.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for designing a modular guardrail. First, the design protection level, the type of vehicle to be protected, and the maximum deformation control index (VInmax) of the guardrail are determined. Then, the minimum distance (Hcmin) from the top surface of the concrete base to the road surface and the minimum distance (Htmin) from the top surface of the modular guardrail to the road surface are determined. Next, an objective function (VIn(X)) = F(Hc, Ht, Stc, Stp, Lp, Stb, San, N) is constructed for finite element seismic analysis. The case with the least amount of upper metal beam-column structure among the results where VIn(X) ≤ VInmax is selected. Based on the results corresponding to this case, Hc, Ht, Stc, Stp, Lp, Stb, San, and N are determined. Then, concrete of the corresponding strength is selected according to the results of S3, and the bearing capacity of the concrete base is calculated before reinforcement is designed. This application overcomes the deficiency in the prior art where the deformation control index of existing modular guardrails does not meet standard requirements when there are tall obstacles such as signposts, gantry posts, and light poles on the outside of the modular guardrail that require protection. Attached Figure Description

[0019] Figure 1 This is a structural schematic diagram of the combined guardrail of the present invention; Figure 2 This is a schematic diagram of vehicle roll during a simulated crash test using a modular guardrail. Figure 1 ; Figure 3 This is a schematic diagram of vehicle roll during a simulated crash test using a modular guardrail. Figure 2 ; Figure 4 This is a structural diagram of a combined guardrail simulation. Figure 1 ; Figure 5 This is a structural diagram of a combined guardrail simulation. Figure 2 ; Figure 6 This is a structural diagram of a combined guardrail simulation. Figure 3 ; Figure 7 This is a simulation analysis comparison diagram of the F-type concrete base slope type guardrail; Figure 8 This is a simulation analysis and comparison diagram of a single-slope concrete base slope type guardrail; Figure 9 This is a simulation analysis comparison diagram of a straight-wall type concrete base slope type guardrail; Figure 10 It is a time history curve of the collision force between a vehicle and the guardrail in the X and Y directions, calculated by simulation of HA-level combined guardrail. Figure 11 It is a time history curve of the lateral collision load of a car; Figure 12 This is a time history curve of the lateral collision load of a car after the moving average processing. Figure 13 This is a finite element modeling analysis diagram of a composite guardrail; Figure 14 This is a finite element modeling analysis diagram of the anchor bolts; Figure 15 This is a schematic diagram of finite element simulation calculation of vehicle-to-barrier collision. Figure 1 ; Figure 16 This is a schematic diagram of finite element simulation calculation of vehicle-to-barrier collision. Figure 2 ; Figure 17 This is a schematic diagram of finite element simulation calculation of vehicle-to-barrier collision. Figure 3 ; Figure 18 This is a flowchart of a method for designing a modular guardrail according to the present invention.

[0020] icon: 1-Upper metal beam-column structure, 101-Crossbeam, 102-Column, 2-Concrete base, 3-Bridge deck, 301-Bridge deck paving, 4-Anchor bolts, 5-Designed protective vehicle type. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0022] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0023] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0024] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0025] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as 2, 3, 4, 5, 6, 7, 8, or 9, and can even exceed nine.

[0026] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0027] Example 1 like Figures 2 to 18 As shown, a method for designing a modular guardrail includes the following steps: S1. Determine the design protection level and design protection vehicle type 5 based on the usage scenario of the combined guardrail; determine the maximum deformation control index VInmax of the guardrail based on the width of the guardrail surface and the width of the obstacle. S2. Based on the typical wheel radius of the designed protective vehicle 5, determine the minimum distance Hcmin from the top surface of the concrete base 2 to the road surface; based on the typical height Htci of the main structural frame of the designed protective vehicle 5, determine the minimum distance Htmin from the top surface of the combined guardrail to the road surface. S3. Construct the objective function VIn(X) = F(Hc, Ht, Stc, Stp, Lp, Stb, San, N), where VIn is the guardrail deformation control index, Hc is the height of the concrete base 2, Ht is the height of the combined guardrail, Stc is the form of the concrete base 2, Stp is the cross-sectional form of the column 102, Lp is the spacing of the column 102, Stb is the cross-sectional form of the beam 101, San is the arrangement of the beam 101, and N is the number of beams 101. Perform finite element simulation analysis on the combined guardrail designed to protect against collisions with vehicle model 5. Select the case with the least amount of upper metal beam-column structure 1 among the results of VIn(X) ≤ VInmax, and determine Hc, Ht, Stc, Stp, Lp, Stb, San and N based on the results corresponding to this case. S4. Based on the Stc determined in S3, select concrete of the corresponding strength, calculate the bearing capacity of the concrete base 2, and then reinforce it to complete the design of the composite guardrail.

[0028] The design protection levels include: HA, HB (Extra High Protection Level), SS (High Protection Level), SA (Relatively High Protection Level), and SB (General Protection Level). The design protection vehicle types include: small passenger cars (1.5t), large passenger cars (18t), extra-large passenger cars (25t), large freight cars (33t), and saddle-type trains (55t).

[0029] When the height of the concrete base is greater than or equal to the radius of the vehicle, it can effectively reduce the uneven force on the wheels during a vehicle collision, making the vehicle guidance smoother. The main structural frame of the protected vehicle model 5 is determined according to the type of the vehicle being designed. The objective function Vin(X) is the value of the guardrail deformation control index Vin, calculated based on subsequent parameters. When Vin(X) ≤ Vinmax, the values ​​of Hc, Ht, Lp, and N, as well as the forms of Ste, Stp, and San, are determined with the minimum amount of the upper metal beam-column structure 1. Minimizing the amount of the upper metal beam-column structure 1 helps to save costs, enhance durability, and improve structural stability. This application provides a design method for a composite guardrail, providing a basis for the design of composite guardrails.

[0030] Furthermore, when there is more than one type of protective vehicle model 5, the maximum value of the typical wheel radius of different types is taken as Hcmin.

[0031] Furthermore, when obtaining typical wheel radius values, the selected wheel radii are first sorted from smallest to largest and a cumulative percentage curve is plotted. Then, the value at 85% is taken as the typical wheel radius value.

[0032] Furthermore, when calculating the bearing capacity of the concrete base 2 in S4, the collision load of the concrete base 2 is taken as the maximum value between the standard value of the lateral collision load of the bridge railing and the peak value of the collision force of the bridge railing extracted by simulation analysis.

[0033] Furthermore, the peak impact force of the bridge railing extracted through simulation analysis includes the following steps: A1. Based on the time history curve of the collision force between the designed protective vehicle 5 and the guardrail, obtain the lateral collision load curve of the designed protective vehicle 5. A2. Perform moving average processing on the lateral collision load curve and obtain the peak value of the collision force of the bridge guardrail.

[0034] Furthermore, after S4, based on the parameters determined in S3, a finite element model of the combined guardrail and the designed protective vehicle model 5 is established and analyzed in the modeling platform. If the design requirements of the combined guardrail are not met, S3 and S4 are repeated until the design requirements of the combined guardrail are met.

[0035] Furthermore, when establishing the finite element model in the modeling platform, the anchor bolt 4 model includes a first unit and a second unit. The first unit is set inside the concrete base 2 and is modeled in the form of a beam element. The first unit is used for coupling analysis with the concrete base 2. The second unit is set on the upper part of the concrete base 2 and is modeled in the form of a beam element enclosing a shell element. The second unit is used for contact analysis with the upper metal beam-column structure 1.

[0036] Furthermore, in S2, when the designed protected vehicle type 5 is a passenger car, the typical height value Htci of the main structural frame is taken as the typical height value of the vehicle frame; when the designed protected vehicle type 5 is a freight car, the typical height value Htci of the main structural frame is taken as the typical height value of the cargo box floor; when the designed protected vehicle type 5 is both a passenger car and a freight car, the typical height value Htci of the main structural frame is taken as the larger of the typical height value of the vehicle frame and the typical height value of the cargo box floor.

[0037] Furthermore, when determining the value or form of a certain parameter in S3, it is determined by the method of controlling variables.

[0038] The following is a detailed explanation: (1) Determine the protection level and Vin value limit requirements The design protection level of the combined guardrail (SB, SA, SS, HB, HA) is determined according to the requirements. The limit requirement (VInmax) of the guardrail deformation control index is determined according to the width of the guardrail surface and the obstacle.

[0039] (2) Determination of the protective vehicle model Based on the determined design protection level, the design protection vehicle type is determined to be 5. For example, if the guardrail design protection level is SS, then small passenger cars (1.5t), large passenger cars (18t), and large trucks (33t) are selected as the design protection vehicle types.

[0040] (3) Determine the height of the concrete base 2 and the total height of the upper metal beam-column structure 1. The composite guardrail consists of two parts: a lower concrete base 2 and an upper metal beam-column structure 1. The higher the total height of the concrete base 2 and the crossbeam 101, the less lateral tilt the guardrail will have after a vehicle collision, and the lower its VIn value. However, a higher concrete base 2 is not necessarily better. Increasing the height increases its self-weight, which in turn increases the load transferred to the bridge deck 3. This requires higher load-bearing capacity of the bridge deck 3, stronger reinforcement, and increased costs.

[0041] The height of the combined guardrail concrete base 2 can be determined according to the wheel radius of the vehicle model 5 being protected. When the height of the concrete base 2 is not lower than the wheel radius, it can effectively reduce the uneven force on the wheels during a vehicle collision, making the vehicle guidance smoother. Figure 2 and Figure 3 As shown. The minimum height of the concrete base 2 is determined by the following formula.

[0042] Hcmin(x)=Max(Rbi,Rtj,Rck) Hcmin is the minimum height of the concrete base above the road surface. Rbi is a typical value for the wheel radius of large and medium-sized buses; Rtj is a typical value for the wheel radius of freight cars (including saddle-type trains).

[0043] Rck is a typical value for the wheel radius of a small passenger vehicle.

[0044] Typical wheel radius values ​​can be obtained by surveying the wheel radii of commercially available guardrail vehicles. For the same vehicle model, data should be plotted as a cumulative percentage curve in ascending order, and the 85th percentile value should be taken as the typical wheel radius value. When survey data is difficult to obtain, values ​​can be determined according to the provisions of current highway guardrail safety performance evaluation standards.

[0045] For example, for HA-class combined guardrails, the typical wheel radius of a 25t large passenger bus is 54cm, and the typical wheel radius of a 40t and 55t freight truck is 52cm. Therefore, the minimum height of the concrete base above the road surface is 54cm.

[0046] The total height of the modular guardrail beam 101 is determined by the height of the truck's cargo box floor. Only when the total height of the modular guardrail is greater than the height of the truck's floor can the guardrail resist vehicle rollover. The minimum total height of the modular guardrail above the road surface is determined by the following formula.

[0047] Htmin(x) = Max(Htci) + Wb The base height Htmin is the minimum total height of the combined guardrail above the road surface; Htci is a typical value for the height of the cargo box floor of a truck. Wb is the selected vertical width of beam 101.

[0048] Typical values ​​for cargo box floor height can be obtained by surveying the cargo box floor heights of commercially available protective trucks, plotting a cumulative percentage curve in ascending order, and taking the 85th percentile value as the typical value. When obtaining survey data is difficult, values ​​can be taken according to the provisions of the current highway guardrail safety performance evaluation standards.

[0049] For example, for HA-grade modular guardrails, the typical height of the cargo box floor of a 40t truck is 125cm, and the typical height of the cargo box floor of a 55t truck is 148cm. If the vertical width of the crossbeam 101 is 12cm, the minimum total height of the modular guardrail above the road surface is 160cm.

[0050] (4) Deformation control index objective function analysis The objective function VIn(X) = F(Hc, Ht, Stc, Stp, Lp, Stb, San, N) is constructed. Through finite element simulation analysis, the total material consumption of the superstructure is minimized while ensuring that the VIn value reaches the limit.

[0051] in: Hc — Height of concrete base 2; Ht—Total height of the combined guardrail; Stc – Slope type; Stp—the cross-sectional shape of column 102; Lp — Spacing of columns 102; Stb—the cross-sectional shape of beam 101; San – Arrangement of beam 101; N—The number of beams 101; During simulation analysis, such as Figures 4-6 As shown, to improve computational efficiency, the concrete base 2 is assumed to be a rigid body and will not be damaged during the calculation. Reinforcement of the concrete base 2 is also ignored. The anchor bolts 4 are not considered to be embedded in the concrete base 2; instead, they are directly connected to the top surface of the concrete base 2 via beam elements. The nodes surrounding the flange bolt holes form a node rigid body, and the centroid of this node rigid body is connected to the top surface of the concrete base 2 via beam elements.

[0052] like Figures 7-9 As shown, taking the slope type analysis of concrete base 2 as an example, when other parameters are the same, the slope type of the impact surface of concrete base 2 has a significant impact on the deformation index value of the guardrail. Through computer simulation analysis, a single slope type is more conducive to controlling vehicle tilt and can effectively reduce the deformation control index value of the guardrail.

[0053] (5) Determination of concrete strength grade and reinforcement Based on the previously determined concrete base type, a suitable concrete strength grade is selected, and the load-bearing capacity of the concrete base is calculated using theoretical analysis methods. Concrete reinforcement design is then carried out, saving the calculation time caused by the detailed reinforcement required in the previous finite element analysis process.

[0054] When calculating the load-bearing capacity, the collision load is based on the standard value of the lateral collision load of the bridge guardrail given in the current "Design Specification for Highway Traffic Safety Facilities" (JTG D81) or the peak value of the collision force extracted by simulation analysis. The larger of the two values ​​is taken to better approximate the actual collision.

[0055] The lateral collision load of a combined guardrail is the sum of the load from the collision beam and the load from the collision concrete base. The collision load of the concrete base can be calculated using the following formula:

[0056] Ftc, lateral collision load of a car on a concrete base; Ft is the maximum value of the standard value of the lateral collision load of the vehicle on the bridge railing and the peak collision force extracted by the simulation analysis. N, the number of crossbeams.

[0057] The height of the point of application of the impact force on the concrete base is the height of the top surface of the concrete base from the bridge deck minus 5cm.

[0058] For HA-grade composite concrete guardrails, such as Figures 10-12 As shown, according to the "Design Specification for Highway Traffic Safety Facilities" (JTG D81), the standard value of the lateral collision load of a vehicle on a bridge guardrail is 720kN, and the lateral collision load of a vehicle on a concrete base is 180kN. The height of the point of application is 590mm from the top surface of the concrete base to the bridge deck.

[0059] Based on the finite element simulation analysis results, the time history curve of the collision force between the vehicle and the guardrail is extracted. The force curve Ftx in the X direction and the force curve Fty in the Y direction are transformed (the formula is as follows) to obtain the collision force (lateral collision load of the car) curve perpendicular to the guardrail direction. The curve is then processed by 10ms moving average.

[0060] Ft=Ftx×sin(θ)+Fty×cos(θ) θ is the collision angle.

[0061] The figure below shows the time history curves of the collision force between the vehicle and the guardrail in the X and Y directions, calculated using a simulation of a HA-level combined guardrail.

[0062] According to the calculation formula for the collision load of the concrete base, the collision load of the concrete base in the simulation analysis is 224.5kN.

[0063] After comparative analysis, the lateral collision load of the concrete base for automobiles was taken as 224.5kN during the load-bearing capacity analysis.

[0064] (6) Full model analysis and verification Based on the above analysis, a detailed finite element modeling analysis is performed, such as... Figures 13-17 As shown. The steel reinforcement and concrete are coupled using a traditional method, with beam elements for the reinforcement and solid elements for the concrete. The anchor bolts are modeled differently than usual, divided into two parts: the portion below the top surface of the concrete is coupled with the concrete using beam elements (composed of multiple nodes N1, N2, N3…), while the portion above the top surface of the concrete is contacted with the metal component using beam elements enclosed in shell elements.

[0065] Example 2 A modular guardrail is designed using a method for designing modular guardrails as described in Example 1.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of designing a modular guardrail, characterized by, The method comprises the following steps: S1, determining the design protection level and the design protection vehicle type (5) according to the use scene of the combined guardrail; determining the maximum deformation control index VInmax of the guardrail according to the width of the guardrail surface and the width of the obstacle; S2, determining the minimum distance Hcmin from the top surface of the concrete base (2) to the road surface according to the typical value of the wheel radius of the design protection vehicle type (5); determining the minimum distance Htmin from the top surface of the combined guardrail to the road surface according to the typical value Htci of the height of the main structural frame of the design protection vehicle type (5); S3, constructing a target function VIn(X)=F(Hc, Ht, Stc, Stp, Lp, Stb, San, N), wherein VIn is the guardrail deformation control index, Hc is the height of the concrete base (2), Ht is the height of the combined guardrail, Stc is the form of the concrete base (2), Stp is the cross-sectional form of the stand column (102), Lp is the stand column (102) spacing, Stb is the cross-sectional form of the crossbeam (101), San is the arrangement of the crossbeam (101), and N is the number of the crossbeam (101), and performing finite element simulation analysis of the design protection vehicle type (5) colliding with the combined guardrail, selecting the working condition with the least amount of upper metal beam column structure (1) in the results of VIn(X)≤VInmax, and determining Hc, Ht, Stc, Stp, Lp, Stb, San and N according to the results corresponding to the working condition; S4, selecting the concrete with corresponding strength according to Stc determined in S3, calculating the bearing capacity of the concrete base (2), and then reinforcing, to complete the design of the combined guardrail.

2. A method of designing a modular guardrail according to claim 1, wherein, When there is more than one kind of design protection vehicle type (5), the maximum value of the typical values of the wheel radii of different kinds of vehicle is taken as Hcmin.

3. A method of designing a modular barrier according to claim 2, wherein, When the typical value of the wheel radius is obtained, the wheel radii are first sorted from small to large according to the selected wheel radii and a cumulative percentage curve is drawn, and then the value at 85% is taken as the typical value of the wheel radius.

4. A method of designing a modular barrier according to any one of claims 1 to 3, wherein, In S4, when the bearing capacity of the concrete base (2) is calculated, the collision load of the concrete base (2) is taken as the maximum value of the standard value of the automobile transverse collision load of the bridge guardrail and the peak value of the bridge guardrail collision force extracted by the simulation analysis.

5. A method of designing a modular barrier according to claim 4, wherein, The peak value of the bridge guardrail collision force extracted by the simulation analysis comprises the following steps: A1, obtaining the transverse collision load curve of the design protection vehicle type (5) according to the time curve of the collision force between the design protection vehicle type (5) and the guardrail; A2, performing moving average processing on the transverse collision load curve, and obtaining the peak value of the bridge guardrail collision force.

6. A method of designing a modular barrier according to any one of claims 1 to 3, wherein, After S4, the parameters determined in S3 are used to establish the finite element model of the combined guardrail and the design protection vehicle type (5) in the modeling platform and perform analysis, if the design requirements of the combined guardrail are not met, S3 and S4 are repeated until the design requirements of the combined guardrail are met.

7. A method of designing a modular barrier according to claim 6, wherein, In the process of establishing a finite element model in a modeling platform, the anchor bolt (4) model comprises a first unit and a second unit, the first unit is arranged inside the concrete base (2), the first unit is modeled in the form of a beam unit, and the first unit is used for coupled analysis with the concrete base (2); the second unit is arranged on the upper portion of the concrete base (2), the second unit is modeled in the form of a beam unit wrapped with a hollow unit, and the second unit is used for contact analysis with the upper metal beam-column structure (1).

8. A method of designing a modular barrier according to any one of claims 1 to 3, wherein, In S2, when the design protection vehicle (5) is a passenger car, the height typical value Htci of the main structure frame is taken as the height typical value of the vehicle frame; when the design protection vehicle (5) is a truck, the height typical value Htci of the main structure frame is taken as the height typical value of the truck bottom plate; when the design protection vehicle (5) is a passenger car and a truck, the height typical value Htci of the main structure frame is taken as the larger one of the height typical value of the vehicle frame and the height typical value of the truck bottom plate.

9. A method of designing a modular barrier according to any one of claims 1 to 3, wherein, In S3, the value or form of a certain parameter is determined by the control variable method.

10. A modular guardrail, characterized in that The design combination guardrail is designed by the method according to any one of claims 1-9.

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