Method and device for calculating bearing capacity of corrugated steel web U-shaped beam under pure torsion action

Abstract

The invention discloses a method and a device for calculating the bearing capacity of a corrugated steel web U-shaped beam under the action of pure torsion, a steel structure part of the corrugated steel web U-shaped beam is equivalent to a concrete structure for simplified calculation, and according to the Vlasov theory, the relationship among the warping bending moment, the warping torque, the free torque and the limit torque is obtained, so that the bearing capacity of the corrugated steel web U-shaped beam is calculated. The warping bending moment is distributed to the webs on the two sides and the bottom plate, the ultimate bearing capacities on the webs and the bottom plate of the midspan section are calculated respectively, and the ultimate bearing capacities are combined with the distributed warping bending moment to obtain the minimum torque of the structure, namely the ultimate torque of the structure. According to the technical scheme, compared with an existing concrete U-shaped beam model, the concrete U-shaped beam model can be suitable for more complex working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of reinforced concrete beam bearing capacity calculation, and in particular relates to a method and device for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion. Background Art

[0002] Due to their advantages such as low construction height, excellent sound insulation, and aesthetic appeal, trough beams are widely used in the construction of urban rail elevated structures and overpasses. To address challenges such as low prestressing efficiency and prone web cracking, they have been continuously developed in recent years. Corrugated steel webs, due to their folding effect, are not subject to axial forces or bending moments, and therefore exhibit high shear buckling resistance. Composite beams with corrugated steel webs combine the advantages of both corrugated steel webs and trough beams, positioning them as a competitive composite structure. However, research on the performance of these structures remains limited. Due to factors such as vehicle sway, wind loads, and curved sections, they are inherently susceptible to torsion, making them susceptible to torsional failure. To date, theoretical analysis and experimental research on composite beams with corrugated steel webs are limited. Existing research has primarily focused on construction techniques, bending and shear performance, and design methods, with limited research on their torsional performance. According to Vlasov's theory, when a structure is subjected to torsion, internal forces such as warping moment, warping torque, and free torque will be generated, further complicating the structural load. Currently, there is no comprehensive theory for calculating the bearing capacity of U-shaped beams with corrugated steel webs under pure torsion. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and device for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion includes:

[0006] Step S1: Equivalent the steel structure of the U-shaped beam with corrugated steel web to a concrete structure;

[0007] Step S2: Based on the equivalent concrete structure, according to Vlasov theory, the warping moment M is obtained. ω , warping torque T ω , free torque T c Relationship with limit torque T;

[0008] Step S3: Distribute the warping moment to the webs and bottom plates on both sides, calculate the ultimate bearing capacity of the web and bottom plates at the mid-span section respectively, and combine them with the distributed warping moment to obtain the minimum torque of the structure, which is the ultimate torque of the structure.

[0009] Preferably, in step S1, the steel structure portion of the corrugated steel web U-shaped beam is equivalent to a concrete structure, including: the corrugated steel plate is first equivalent to a flat steel plate by using the Castigliano theorem, and then the flat steel plate is equivalent to a concrete plate for calculation by using the elastic modulus. Similarly, the upper and lower flange plates of the corrugated steel and the outer steel plate are equivalent to concrete plates for calculation.

[0010] As a preference, in step S1, under the action of the axial force F, the axial deformation of the corrugated steel plate is s1=2F(c 3 / 2+3h 2 a) / E S t 3 , under the action of axial force F, the axial deformation of the flat steel plate of the same length is s2=2F(a+b) / E e t, through s1=s2, equivalent elastic modulus E e =2t 2 (a+b) / (c 3 +6ah 2 )E s =kE s =nkE. Similarly, the elastic modulus of the upper and lower flange steel plates of the corrugated steel and the outer steel skin is converted to E e1 =n1E,E e2 =n2E; where c is the inclined plate length of the corrugated steel plate, a is the plate length of the corrugated steel plate, b is the axial projection length of the inclined plate, h is the wave height, and E S is the elastic modulus of the corrugated steel plate, E e is the elastic modulus of the flat steel plate, E is the elastic modulus of the concrete, and E e1 is the elastic modulus of the upper and lower flange steel plates of the corrugated steel, E e2 is the elastic modulus of the outer rigid skin.

[0011] As a preference, in step S2, according to Vlasov theory, the warping moment M under the conditions of consolidation at both ends and simple support at both ends is ω , warping torque T ω , free torque T c The relationship with the limit torque T is:

[0012]

[0013]

[0014] in, is the characteristic length of the restrained torsion of the U-beam with corrugated steel webs, G is the shear modulus, G = 0.4E, I t is the torsional moment of inertia of the section, t is the thickness of the U-shaped beam section, I ω is the main sector moment of inertia of the U-shaped beam, I ω=∫ A ω 2 dA,ω is the main sector coordinate of the U-shaped beam;

[0015] The warping moment M of the entire section ω The bending moment is distributed through the static moment of the web and bottom plates. The distributed bending moment is:

[0016] M=∫yσ ω dA (3)

[0017] When the ends of the U-shaped beam with corrugated steel web are consolidated and simply supported, the calculation formula for the warping normal stress σ ω =M ω ω / I ω Substitute into formula (3),

[0018] Web equivalent bending moment M fla,w for:

[0019]

[0020] Equivalent bending moment of bottom plate M bot,w for:

[0021]

[0022] Preferably, in step S3,

[0023] (1) When the neutral axis is located at the concrete upper flange plate, the mid-span U-section web is obtained according to the internal force equilibrium condition:

[0024]

[0025] (2) When the neutral axis is located at the corrugated steel upper flange plate, the mid-span U-section web is obtained according to the internal force equilibrium condition:

[0026]

[0027] (3) When the neutral axis is located at the corrugated steel, the mid-span U-section web is obtained according to the internal force equilibrium condition:

[0028]

[0029] Where, f c is the design value of concrete compressive strength, f′ tsd and f td is the design value of tensile strength of concrete flange and steel bar in the slab, f′ ts and f ts f is the design value of tensile strength of the upper and lower flange steel plates on the corrugated steel web, tsd is the design value of tensile strength of the reinforcement in the bottom slab, f osis the design value of tensile strength of the external steel plate. And f ts =f′ ts =f ds , f tsd =f′ tsd =f td , A c , A′ tsd , A td , A′ ts , A ts ,A ds , A tsd and A os Denote the force area corresponding to these tensile and compressive strengths. h c , h′ tsd , h td , h′ ts , h ts , h ds , h tsd and h os Represents the distance between the centroid of each pair of stress components and the neutral axis of the base plate. If the distance is above the neutral axis, it is considered negative (-); if the distance is below the neutral axis, it is considered positive (+);

[0030] The stress analysis of the mid-span U-section bottom plate is as follows:

[0031]

[0032] Among them, A sw represents the area of all distributed reinforcements, and x0 represents the height of the compression zone. The effective area of the distributed reinforcement is expressed as h w0 Indicates the effective height, f c is the design value of concrete compressive strength, f ts and f′ ts is the design value of tensile strength of corrugated steel web flange steel plate, f ts =f′ ts ·f′ tsd , f tsd and f yw Respectively represent the tensile strength design values of tension and compression reinforcement and distribution reinforcement, f′ tsd =f tsd =f yw , f p is the design value of tensile strength of prestressed tendons. os and f′ os are the tensile and compressive design values of the external steel plate, respectively, and f os =f′ os , A c , A ts , A′ ts, A′ tsd , A tsd , A p , A os and A′ os Corresponding to the force area of the previous unit. Take the distance h to the center of the compression area w , h c , h ts , h′ ts , h′ tsd , h tsd , h p , h os and h′ os are the distances from the corresponding force center to the center of the compression area, with values above the center axis being positive (+) and values below the center axis being negative (-);

[0033] Combining formula (4) with formula (6)(7)(8) gives a limit torque T fla,w , combine formula (9) and formula (5)(7)(8) to get a limit torque T bot,w , take the minimum value of the two, the limit torque T=min(T fla,w ,T bot,w ).

[0034] The present invention also provides a device for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion, comprising:

[0035] The first processing module is used to convert the steel structure part of the corrugated steel web U-shaped beam into a concrete structure;

[0036] The second processing module is used to obtain the warping moment M based on the equivalent concrete structure according to Vlasov theory. ω , warping torque T ω , free torque T c Relationship with limit torque T;

[0037] The third processing module is used to distribute the warping bending moment to the webs and bottom plates on both sides, calculate the ultimate bearing capacity of the web and bottom plates in the mid-span section respectively, and combine it with the distributed warping bending moment to obtain the minimum torque of the structure, which is the ultimate torque of the structure.

[0038] Preferably, the first processing module equates the steel structure part of the corrugated steel web U-shaped beam to a concrete structure, including: the corrugated steel plate needs to be first equated to a flat steel plate through the Castigliano theorem, and then the flat steel plate is equated to a concrete plate for calculation through the elastic modulus. Similarly, the upper and lower flange plates of the corrugated steel and the outer steel plate are equated to concrete plates for calculation.

[0039] The present invention is based on the existing concrete U-beam model. In the corrugated steel web U-beam, the internal force balance equation of the dangerous section under pure torsion is considered to derive the relationship between the component's ultimate torque T and the torque magnitude, and thus the ultimate torque T of the structure can be obtained. Compared with the existing concrete U-beam model, the present invention is applicable to more complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0041] Figure 1 This is a flow chart of a method for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion according to an embodiment of the present invention;

[0042] Figure 2 Schematic diagram of the mid-span cross-section of the U-shaped beam with corrugated steel webs in the present invention;

[0043] Figure 3 This is a schematic diagram of the dimensions of the corrugated steel in the present invention;

[0044] Figure 4 Schematic diagram of the distribution of warping normal stress in the present invention;

[0045] Figure 5 The internal force distribution diagram of the U-shaped cross-section web with the neutral axis in the concrete flange plate in the present invention;

[0046] Figure 6 The internal force distribution diagram of the neutral axis in the U-shaped cross-section web of the corrugated steel flange in the present invention;

[0047] Figure 7 The internal force distribution diagram of the neutral axis in the U-shaped cross-section web of the corrugated steel in the present invention;

[0048] Figure 8 This is the internal force distribution diagram of the U-shaped cross-section bottom plate in the present invention. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Example 1:

[0052] like Figure 1 As shown, an embodiment of the present invention provides a method for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion, comprising the following steps:

[0053] Step S1: Figure 2 As shown, the structure is a steel-concrete structure. To simplify the calculation, the steel structure part of the U-shaped beam with corrugated steel webs needs to be equivalent to the concrete structure.

[0054] Step S2: Based on the equivalent concrete structure, according to Vlasov theory, the warping moment M is obtained. ω , warping torque T ω , free torque T c The relationship between the ultimate torque T and the warping moment M of the entire section is ω The bending moment M of the web and bottom plates of the structure is obtained by distributing the static moments of the fan areas of the web and bottom plates. fla,w and M bot,w Relationship with applied torque T;

[0055] Step S3: Distribute the warping moment to the webs and bottom plates on both sides, calculate the ultimate bearing capacity of the web and bottom plates at the mid-span section respectively, and combine them with the distributed warping moment to obtain the minimum torque of the structure, which is the ultimate torque of the structure.

[0056] As an implementation method of an embodiment of the present invention, in step S1, the steel structure part is equivalent to the concrete structure, including: the corrugated steel plate needs to be first equivalent to the flat steel plate through the Castigliano theorem, and then the flat steel plate is equivalent to the concrete plate for calculation through the elastic modulus. The upper and lower flange plates of the corrugated steel and the outer steel plate are similarly equivalent to the concrete plate for calculation.

[0057] like Figure 3 As shown in the figure, under the action of axial force F, the axial deformation of the corrugated steel plate is s1=2F(c 3 / 2+3h 2 a) / E S t 3 , under the action of axial force F, the axial deformation of the flat steel plate of the same length is s2=2F(a+b) / E e t, through s1=s2, equivalent elastic modulus E e =2t 2 (a+b) / (c 3 +6ah 2 )E s =kEs =nkE. Similarly, the elastic modulus of the upper and lower flange steel plates of the corrugated steel and the outer steel skin is converted to E e1 =n1E,E e2 =n2E.

[0058] Where c is the inclined plate length of the corrugated steel plate, a is the plate length of the corrugated steel plate, b is the axial projection length of the inclined plate, h is the wave height, E S is the elastic modulus of the corrugated steel plate, E e is the elastic modulus of the flat steel plate, E is the elastic modulus of the concrete, and E e1 is the elastic modulus of the upper and lower flange steel plates of the corrugated steel, E e2 is the elastic modulus of the outer rigid skin.

[0059] As an implementation method of the embodiment of the present invention, in step S2, according to the Vlasov theory, the warping moment M under the conditions of consolidation at both ends and simple support at both ends is: ω , warping torque T ω , free torque T c The relationship with the limit torque T is:

[0060]

[0061] in, is the characteristic length of the restrained torsion of the U-beam with corrugated steel webs, G is the shear modulus, G = 0.4E, I t is the torsional moment of inertia of the section, t is the thickness of the U-shaped beam section, I ω is the main sector moment of inertia of the U-shaped beam, I ω =∫ A ω 2 dA,ω are the main sector coordinates of the U-shaped beam.

[0062] like Figure 4 As shown, the warping moment M of the entire section ω The bending moment is distributed through the static moment of the web and bottom plates. The distributed bending moment is:

[0063] M=∫yσ ω dA (3)

[0064] When the ends of the U-shaped beam with corrugated steel web are consolidated and simply supported, the calculation formula for the warping normal stress σ ω =M ω ω / I ω Substitute into formula (3), the web equivalent bending moment M fla,w for:

[0065]

[0066] Equivalent bending moment of bottom plate M bot,w for:

[0067]

[0068] As an implementation method of an embodiment of the present invention, in step S3, the force analysis of the mid-span U-section web requires determining the position of the neutral axis and then obtaining the internal force balance of the mid-span U-section web.

[0069] (1) Figure 5 As shown in the figure, when the neutral axis is located at the concrete upper flange plate, the mid-span U-section web is obtained according to the internal force equilibrium condition:

[0070]

[0071] (2) Figure 6 As shown in the figure, when the neutral axis is located at the corrugated steel upper flange plate, the mid-span U-section web is obtained according to the internal force equilibrium condition:

[0072]

[0073] (3) Figure 7 As shown in the figure, when the neutral axis is located at the corrugated steel, the mid-span U-section web is obtained according to the internal force equilibrium condition:

[0074]

[0075] Where, f c is the design value of concrete compressive strength, f′ tsd and f td is the design value of tensile strength of concrete flange and steel bar in the slab, f′ ts and f ts f is the design value of tensile strength of the upper and lower flange steel plates on the corrugated steel web, tsd is the design value of tensile strength of the reinforcement in the bottom slab, f os is the design value of tensile strength of the external steel plate. And f ts =f′ ts =f ds , f tsd =f′ tsd =f td , A c , A′ tsd , A td , A′ ts , A ts ,A ds , A tsd and A os Denote the force area corresponding to these tensile and compressive strengths. h c , h′ tsd , h td , h′ts , h ts , h ds , h tsd and h os Represents the distance between the centroid of each pair of stress components and the neutral axis of the base plate. If the distance is above the neutral axis, it is considered negative (-); if the distance is below the neutral axis, it is considered positive (+).

[0076] like Figure 8 As shown in the figure, the stress analysis of the mid-span U-section bottom plate is:

[0077]

[0078] Among them, A sw represents the area of all distributed reinforcements, and x0 represents the height of the compression zone. The effective area of the distributed reinforcement is expressed as h w0 Indicates the effective height, f c is the design value of concrete compressive strength, f ts and f′ ts is the design value of tensile strength of corrugated steel web flange steel plate, f ts =f′ ts ·f′ tsd , f tsd and f yw Respectively represent the tensile strength design values of tension and compression reinforcement and distribution reinforcement, f′ tsd =f tsd =f yw , f p is the design value of tensile strength of prestressed tendons. os and f′ os are the tensile and compressive design values of the external steel plate, respectively, and f os =f′ os , A c , A ts , A′ ts , A′ tsd , A tsd , A p , A os and A′ os Corresponding to the force area of the previous unit. Take the distance h to the center of the compression area w , h c , h ts , h′ ts , h′ tsd , h tsd , h p , h os and h′ osThey are the distances from the corresponding force center to the center of the compression area, with values above the center axis being positive (+) and values below the center axis being negative (-).

[0079] Combining formula (4) with formula (6)(7)(8) gives a limit torque T fla,w , combine formula (9) and formula (5)(7)(8) to get a limit torque T bot,w , take the minimum value of the two, the limit torque T=min(T fla,w ,T bot,w ).

[0080] Example 2:

[0081] An embodiment of the present invention further provides a device for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion, comprising:

[0082] The first processing module is used to convert the steel structure part of the corrugated steel web U-shaped beam into a concrete structure;

[0083] The second processing module is used to obtain the warping moment M based on the equivalent concrete structure according to Vlasov theory. ω , warping torque T ω , free torque T c Relationship with limit torque T;

[0084] The third processing module is used to distribute the warping bending moment to the webs and bottom plates on both sides, calculate the ultimate bearing capacity of the web and bottom plates in the mid-span section respectively, and combine it with the distributed warping bending moment to obtain the minimum torque of the structure, which is the ultimate torque of the structure.

[0085] As an implementation method of an embodiment of the present invention, the first processing module equates the steel structure part of the corrugated steel web U-shaped beam to a concrete structure, including: the corrugated steel plate needs to be first equated to a flat steel plate through the Castigliano theorem, and then the flat steel plate is equated to a concrete plate for calculation through the elastic modulus. The upper and lower flange plates of the corrugated steel and the outer steel plate are similarly equated to concrete plates for calculation.

[0086] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion, characterized in that: include: Step S1: Equivalent the steel structure of the U-shaped beam with corrugated steel web to a concrete structure; Step S2: Based on the equivalent concrete structure, according to Vlasov theory, the warping moment M is obtained. ω , warping torque T ω , free torque T c Relationship with limit torque T; Step S3: Distribute the warping moment to the webs and bottom plates on both sides, calculate the ultimate bearing capacity of the web and bottom plates at the mid-span section respectively, and combine them with the distributed warping moment to obtain the minimum torque of the structure, which is the ultimate torque of the structure.

2. The method for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion according to claim 1, wherein: In step S1, the steel structure of the U-shaped beam with a corrugated steel web is equivalent to a concrete structure, including: the corrugated steel plate is first equivalent to a flat steel plate using the Castigliano theorem, and then the flat steel plate is equivalent to a concrete plate for calculation using the elastic modulus. The upper and lower flange plates of the corrugated steel and the outer steel plate are similarly equivalent to concrete plates for calculation.

3. The method for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion according to claim 2, wherein: In step S1, under the action of the axial force F, the axial deformation of the corrugated steel plate is s1=2F(c 3 / 2+3h 2 a) / E S t 3 , under the action of axial force F, the axial deformation of the flat steel plate of the same length is s2=2F(a+b) / E e t, through s1=s2, equivalent elastic modulus E e =2t 2 (a+b) / (c 3 +6ah 2 )E s =kE s =nkE. Similarly, the elastic modulus of the upper and lower flange steel plates of the corrugated steel and the outer steel skin is converted to E e1 =n1E,E e2 =n2E; where c is the inclined plate length of the corrugated steel plate, a is the plate length of the corrugated steel plate, b is the axial projection length of the inclined plate, h is the wave height, and E S is the elastic modulus of the corrugated steel plate, E e is the elastic modulus of the flat steel plate, E is the elastic modulus of the concrete, and E e1 is the elastic modulus of the upper and lower flange steel plates of the corrugated steel, E e2 is the elastic modulus of the outer rigid skin.

4. The method for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion according to claim 3, wherein: In step S2, according to Vlasov theory, the warping moment M under the conditions of consolidation at both ends and simple support at both ends is ω , warping torque T ω , free torque T c The relationship with the limit torque T is: in, is the characteristic length of the restrained torsion of the U-beam with corrugated steel webs, G is the shear modulus, G = 0.4E, I t is the torsional moment of inertia of the section, t is the thickness of the U-shaped beam section, I ω is the main sector moment of inertia of the U-shaped beam, I ω =∫ A ω 2 dA,ω is the main sector coordinate of the U-shaped beam; The warping moment M of the entire section ω The bending moment is distributed through the static moment of the web and bottom plates. The distributed bending moment is: M=∫yσ ω yes (3) When the ends of the U-shaped beam with corrugated steel web are consolidated and simply supported, the calculation formula for the warping normal stress σ ω =M ω ω / I ω Substitute into formula (3), Web equivalent bending moment M fla,w for: Equivalent bending moment of bottom plate M bot,w for:

5. The method for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion according to claim 4 is characterized in that: In step S3, (1) When the neutral axis is located at the concrete upper flange plate, the mid-span U-section web is obtained according to the internal force equilibrium condition: (2) When the neutral axis is located at the corrugated steel upper flange plate, the mid-span U-section web is obtained according to the internal force equilibrium condition: (3) When the neutral axis is located at the corrugated steel, the mid-span U-section web is obtained according to the internal force equilibrium condition: Where, f c is the design value of concrete compressive strength, f' tsd and f td is the design value of tensile strength of concrete flange and steel bar in the slab, f' ts and f ts f is the design value of tensile strength of the upper and lower flange steel plates on the corrugated steel web, tsd is the design value of tensile strength of the reinforcement in the bottom slab, f os is the design value of tensile strength of the external steel plate. And f ts =f' ts =f ds , f tsd =f' tsd =f td , A c , A' tsd , A td , A' ts , A ts ,A ds , A tsd and A os Denote the force area corresponding to these tensile and compressive strengths. h c , h' tsd , h td , h' ts , h ts , h ds , h tsd and h os Represents the distance between the centroid of each pair of stress components and the neutral axis of the base plate. If the distance is above the neutral axis, it is considered negative (-); If the distance lies below the neutral axis, it is considered positive (+); The stress analysis of the mid-span U-section bottom plate is as follows: Among them, A sw represents the area of all distributed reinforcements, and x0 represents the height of the compression zone. The effective area of the distributed reinforcement is expressed as h w0 Indicates the effective height, f c is the design value of concrete compressive strength, f ts and f' ts is the design value of tensile strength of corrugated steel web flange steel plate, f ts =f' ts ·f' tsd , f tsd and f yw Respectively represent the tensile strength design values of tension and compression reinforcement and distribution reinforcement, f' tsd =f tsd =f yw , f p is the design value of tensile strength of prestressed tendons. os and f' os are the tensile and compressive design values of the external steel plate, respectively, and f os =f' os , A c , A ts , A' ts , A' tsd , A tsd , A p , A os and A' os Corresponding to the force area of the previous unit. Take the distance h to the center of the compression area w , h c , h ts , h' ts , h' tsd , h tsd , h p , h os and h' os are the distances from the corresponding force center to the center of the compression area, with values above the center axis being positive (+) and values below the center axis being negative (-); Combining formula (4) with formula (6)(7)(8) gives a limit torque T fla,w , combine formula (9) and formula (5)(7)(8) to get a limit torque T bot,w , take the minimum value of the two, the limit torque T=min(T fla,w ,T bot,w ).

6. A device for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion, characterized in that: include: The first processing module is used to convert the steel structure part of the corrugated steel web U-shaped beam into a concrete structure; The second processing module is used to obtain the warping moment M based on the equivalent concrete structure according to Vlasov theory. ω , warping torque T ω , free torque T c Relationship with the limit torque T; The third processing module is used to distribute the warping bending moment to the webs and bottom plates on both sides, calculate the ultimate bearing capacity of the web and bottom plates in the mid-span section respectively, and combine it with the distributed warping bending moment to obtain the minimum torque of the structure, which is the ultimate torque of the structure.

7. The device for calculating the bearing capacity of a U-shaped beam with a corrugated steel web under pure torsion according to claim 6, characterized in that: The first processing module equates the steel structure of the corrugated steel web U-shaped beam to a concrete structure, including: the corrugated steel plate needs to be equated to a flat steel plate using the Castigliano theorem, and then the flat steel plate is equated to a concrete plate for calculation using the elastic modulus. The upper and lower flange plates of the corrugated steel and the outer steel plate are similarly equated to concrete plates for calculation.

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