Corrugated steel web box girder limit state analysis method, terminal and storage medium

Abstract

The invention provides a corrugated steel web box girder limit state analysis method, a terminal and a storage medium, and belongs to the technical field of electric digital data processing. The invention provides a method for analyzing the limit state of a corrugated steel web box girder, which comprises the following steps of: introducing three failure modes in the limit state of the corrugated steel web box girder, namely a failure mode I (bending failure), a failure mode II (twisting failure) and a failure mode III (bending and twisting failure); respectively calculating a bending moment formula and a torque formula under the three failure modes; unifying the bending moment formulas and the torque formulas in the three failure modes to obtain a bending-torsion failure envelope diagram; and according to the obtained bending and twisting damage envelope diagram, determining the types of damage modes generated under different conditions. According to the method for analyzing the limit state of the corrugated steel web box girder, provided by the invention, by drawing the bending and twisting damage envelope diagrams of the three damage modes, the damage forms of the corrugated steel web box girder under different conditions can be analyzed and obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of electric digital data processing, and in particular relates to a limit state analysis method, a terminal and a storage medium of a corrugated steel web box girder. Background Art

[0002] The traditional concrete box girder is composed of a top plate, a bottom plate, a web plate, a diaphragm, a support beam, etc. The top plate, the bottom plate, the web plate, the diaphragm, the support beam, etc. are usually made of reinforced concrete structure. The traditional concrete box girder gradually exposed some problems during use. With the increase of span, the deadweight of the box girder increases rapidly, so a stronger lower structure is needed for support. The corresponding amount of materials required for the lower structure increases, and the overall cost rises. In addition, the concrete web is prone to cracks due to environmental influences, which affects the durability of use. The composite box girder with corrugated steel web uses corrugated steel plates as the webs of the box girder to replace the traditional concrete webs. The top plate and the bottom plate are still made of reinforced concrete structure, and longitudinal steel bars, transverse steel bars, prestressed bars, etc. are provided. The corrugated steel plate has high shear strength and stability, and is relatively light in weight. It can effectively reduce the deadweight of the box girder, reduce the amount of materials used in the lower structure, and reduce production costs. In actual use, the torsional stiffness and anti-distortion stiffness of the composite box girder with corrugated steel web are lower than those of the traditional concrete box girder. The buckling failure of the corrugated steel web is relatively sudden. As the service life increases, the performance will degrade, affecting the service life. In order to improve the safety of the composite box girder with corrugated steel web, it is necessary to analyze the failure mode of the composite box girder with corrugated steel web. However, the existing traditional concrete box girder is not suitable for the failure mode analysis of the composite box girder with corrugated steel web. Summary of the invention

[0003] The object of the present invention is to provide a limit state analysis method, a terminal and a storage medium for a corrugated steel web box girder, aiming to solve the problem of failure mode analysis of a corrugated steel web composite box girder.

[0004] To achieve the above object, the technical solution adopted by the present invention is: to provide a limit state analysis method of a corrugated steel web box girder, comprising the following steps: S1. Three failure modes of the ultimate state of the corrugated steel web box girder are introduced, namely failure mode I (bending failure), failure mode II (torsion failure) and failure mode III (bending-torsion failure); S2. Calculate the bending moment formula and torque formula under the three failure modes respectively; S3. Unify the bending moment formula and torque formula under the three failure modes to obtain the bending-torsion failure envelope diagram; S4. Determine the type of failure mode produced under different conditions based on the obtained bending-torsion failure envelope diagram.

[0005] In one possible implementation, during the calculation process, the section formed after the damage of the corrugated steel web box girder occurs is defined as a torsional damage surface, and the point of action of the combined compressive force is selected on the torsional damage surface, and the force at the point of action of the combined compressive force is analyzed to obtain the bending moment formula and torque formula at the point of action of the combined compressive force.

[0006] In one possible implementation, in the case of failure mode I (bending failure), when the stress of the bottom plate reinforcement reaches the tensile yield, the cracks rapidly develop into failure mode I (bending failure), and the point of action of the compressive force is on the top plate.

[0007] In one possible implementation, in the case of failure mode II (torsional failure), the tensile stress generated by the torque offsets the compressive stress generated by the positive bending moment in the top plate, and the longitudinal reinforcement of the top plate reaches the yield strength earlier than the longitudinal reinforcement of the bottom plate. Cracks are formed in the top plate and extend to the corrugated steel webs on both sides. Due to the yielding of the longitudinal reinforcement of the top plate, the oblique compression surface produces a plastic hinge that rotates downward, and the bottom plate concrete is compressed, developing into failure mode II (torsional failure), and the point of action of the resultant compressive force is on the bottom plate.

[0008] In one possible implementation, in the case of failure mode III (bending-torsion failure), the directions of the principal tensile stresses generated by the torque and the vertical shear force are consistent, cracks are formed on the side walls of the top plate and the bottom plate, and extend to the plate surfaces of the top plate and the bottom plate. The directions of the principal tensile stresses on the top plate and the bottom plate are opposite, and the cracks on the side walls of the top plate and the bottom plate are suppressed. One of the side walls of the top plate and the bottom plate is subjected to tension and the other is subjected to compression, developing into failure mode III (bending-torsion failure), and the point of action of the resultant compressive force is on the corrugated steel web.

[0009] In one possible implementation, the force at the point of action of the resultant compressive force is analyzed, a local coordinate system is established at the point of action of the resultant compressive force, and the stress under different failure modes is analyzed. x Axial force, y Axial forces and z The force in the axial direction, x The axial forces include the forces generated by the top plate, bottom plate, longitudinal reinforcement, and prestressed tendons. y The axial force includes the force generated by the transverse reinforcement. z The axial force includes the vertical force acting on the corrugated steel web at the boundary of the torsional failure surface.

[0010] In one possible implementation, the bending-torsion failure envelope diagram is based on the ratio of the bending moment at the point of action of the combined compressive force to the ultimate bending moment under pure bending. x The ratio of the torque at the point of action of the combined pressure force to the limit torque under pure torsion is yAxis, the relationship between bending moment and torque under the three failure modes are plotted into the same bending-torsion failure envelope diagram, and the failure curves under the three failure modes are obtained. The type of failure that occurs is determined according to the positions of the three groups of failure curves.

[0011] In one possible implementation, y In the axial direction, the failure mode represented by the failure curve at the bottom occurs.

[0012] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of any of the above methods when executing the computer program.

[0013] To achieve the above object, the technical solution adopted by the present invention is: to provide a computer-readable storage medium, the computer-readable storage medium stores a computer program, characterized in that when the computer program is executed by a processor, the steps of any of the above methods are implemented.

[0014] The beneficial effects of the limit state analysis method of a corrugated steel web box girder provided by the present invention are: Compared with the prior art, various parameters of the corrugated steel web box girder, such as the size and position of the top plate, bottom plate, web and diaphragm, support beam, longitudinal steel bar, transverse steel bar, and prestressed tendons, are determined. According to various parameters of the corrugated steel web box girder, a virtual model of the corrugated steel web box girder is established, and the ultimate state of the corrugated steel web box girder is analyzed. With reference to the traditional concrete box girder, three failure modes of the corrugated steel web box girder under the ultimate state are introduced, namely failure mode I (bending failure), failure mode II (torsion failure) and failure mode III (bending-torsion failure). The ultimate state of the corrugated steel web box girder under different failure modes is subjected to stress analysis, and the compressive resultant force on the corrugated steel web box girder under different failure modes is obtained. The moment formula and torque formula of the action point are unified for the moment formula and torque formula under the same failure mode to obtain the relationship between the moment and torque. The analytical curve is drawn through the relationship. The analytical curves related to the moment and torque under the three failure modes are drawn in the same figure, that is, the bending-torsion failure envelope diagram is obtained. According to the obtained bending-torsion failure envelope diagram, the type of failure mode generated by the virtual model of the corrugated steel web box girder is determined. Through virtual analysis and calculation, the failure mode analysis of the corrugated steel web box girder is carried out. According to the analysis results, the various parameters of the corrugated steel web box girder are adjusted, which greatly improves the safety of the corrugated steel web box girder during construction and use and reduces the analysis cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A three-dimensional structural schematic diagram of failure mode I (bending failure) of the limit state analysis method of a corrugated steel web box girder provided in an embodiment of the present invention; Figure 2 A schematic diagram of the top view of the failure mode I (bending failure) of the limit state analysis method of the corrugated steel web box girder provided in an embodiment of the present invention; Figure 3 A schematic side view of the structure of failure mode I (bending failure) of the limit state analysis method of a box girder with corrugated steel webs provided in an embodiment of the present invention; Figure 4 A schematic diagram of the three-dimensional structure of failure mode II (torsion failure) of the limit state analysis method of a corrugated steel web box girder provided in an embodiment of the present invention; Figure 5 A schematic diagram of the top view of the failure mode II (torsion failure) of the limit state analysis method of the corrugated steel web box girder provided in an embodiment of the present invention; Figure 6 A schematic side view of the structure of the failure mode II (torsion failure) of the limit state analysis method of the corrugated steel web box girder provided in an embodiment of the present invention; Figure 7 A schematic diagram of the three-dimensional structure of the failure mode III (bending-torsion failure) of the limit state analysis method of the corrugated steel web box girder provided in an embodiment of the present invention; Figure 8 A schematic diagram of the top view of the failure mode III (bending-torsion failure) of the limit state analysis method of the corrugated steel web box girder provided in an embodiment of the present invention; Fig. 9 A schematic diagram of the side view structure of the failure mode III (bending-torsion failure) of the limit state analysis method of the corrugated steel web box girder provided in an embodiment of the present invention; Fig.10 Bending and torsion failure envelope of the limit state analysis method of the corrugated steel web box girder provided in the embodiment of the present invention Figure 1 ; Fig.11 Bending and torsion failure envelope of the limit state analysis method of the corrugated steel web box girder provided in the embodiment of the present invention Figure 2 ; Fig.12 Bending and torsion failure envelope of the limit state analysis method of the corrugated steel web box girder provided in the embodiment of the present invention Figure 3.

[0017] In the figure: 1. Top plate; 2. Bottom plate; 3. Corrugated steel web; 4. Twisted failure surface; 5. Longitudinal reinforcement; 6. Transverse reinforcement; 7. Prestressed tendons. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] Please refer to Figures 1 to 12 A specific implementation method of a limit state analysis method of a corrugated steel web box girder provided by the present invention is now described, comprising the following steps: S1. Three failure modes of the ultimate state of the corrugated steel web box girder are introduced, namely failure mode I (bending failure), failure mode II (torsion failure) and failure mode III (bending-torsion failure); S2. Calculate the bending moment formula and torque formula under the three failure modes respectively; S3. Unify the bending moment formula and torque formula under the three failure modes to obtain the bending-torsion failure envelope diagram; S4. Determine the type of failure mode produced under different conditions based on the obtained bending-torsion failure envelope diagram.

[0020] The present invention provides a method for analyzing the limit state of a corrugated steel web box girder. Compared with the prior art, the present invention determines various parameters of the corrugated steel web box girder, such as the size and position of the top plate 1, the bottom plate 2, the web and the diaphragm, the support beam, the longitudinal steel bar 5, the transverse steel bar 6, and the prestressed bar 7. According to the various parameters of the corrugated steel web box girder, a virtual model of the corrugated steel web box girder is established to analyze the limit state of the corrugated steel web box girder. With reference to the traditional concrete box girder, three failure modes of the corrugated steel web box girder under the limit state are introduced, namely, failure mode I (bending failure), failure mode II (torsion failure) and failure mode III (bending-torsion failure). The force analysis of the limit state of the corrugated steel web box girder under different failure modes is carried out to obtain different failure modes. The moment formula and torque formula of the compressive force acting point on the corrugated steel web box girder under the present invention are proposed, and the moment formula and torque formula under the same failure mode are unified to obtain the relationship between the moment and torque. The analytical curve is drawn through the relationship, and the analytical curves related to the moment and torque under the three failure modes are drawn in the same figure, that is, the bending-torsion failure envelope diagram is obtained. According to the obtained bending-torsion failure envelope diagram, the type of failure mode generated by the virtual model of the corrugated steel web box girder is determined, and the failure mode of the corrugated steel web box girder is analyzed through virtual analysis and calculation. According to the analysis results, the various parameters of the corrugated steel web box girder are adjusted, which greatly improves the safety of the corrugated steel web box girder during construction and use and reduces the analysis cost.

[0021] For details, please refer to Figures 1 to 12For traditional concrete box girders, the limit state calculation method of "oblique bending failure theory" is adopted. According to the different torsion-bending ratios, there are three classic bending-torsion failure modes, namely bending failure, torsion failure and bending-torsion failure. Under bending failure, the compression zone under the action of positive bending moment and torque occurs in the bottom plate of the concrete box girder 2 respectively. Under torsion failure, the compression zone under the action of positive bending moment and torque occurs in the top plate of the concrete box girder 1 respectively. For bending-torsion failure, the compression zone under the action of positive bending moment and torque occurs in the side web of the concrete box girder. For the limit state analysis of the three bending-torsion failure modes of concrete box girders, there are relevant analysis formulas. The corrugated steel web box girder uses corrugated steel plates to replace the webs of traditional concrete box girders. When performing the limit state analysis, the three bending-torsion failure modes of concrete box girders are introduced into the limit state analysis of the corrugated steel web box girder, which are failure mode I (bending type The ultimate limit state analysis of the three failure modes of the corrugated steel web box girder is carried out respectively, and the relationship between the bending moment and the torque in the three failure modes is obtained. The relationship between the bending moment and the torque is converted into an analytical curve and plotted in a plane coordinate system. The analytical curves related to the bending moment and the torque in the three failure modes of the same corrugated steel web box girder are plotted in the same plane coordinate system, and the bending-torsion failure envelope diagram is obtained. According to the obtained bending-torsion failure envelope diagram, the type of failure mode generated by the virtual model of the corrugated steel web box girder is determined. Through virtual analysis and calculation, the failure mode analysis of the corrugated steel web box girder is carried out, and the various parameters of the corrugated steel web box girder are adjusted according to the analysis results, which greatly improves the safety of the corrugated steel web box girder during construction and use and reduces the analysis cost.

[0022] As a specific implementation of the limit state analysis method of a corrugated steel web box girder provided by the present invention, please refer to Figures 1 to 9 In the calculation process, the section formed after the damage of the corrugated steel web box girder is defined as the torsional damage surface 4. The point of action of the combined compressive force is selected on the torsional damage surface 4, and the force at the point of action of the combined compressive force is analyzed to obtain the bending moment formula and torque formula at the point of action of the combined compressive force.

[0023] For details, please refer to Figures 1 to 9 In the process of force analysis, the cross section formed after the damage of the corrugated steel web box girder is defined as the torsional damage surface 4. The torsional damage surface 4 is a virtual surface. It is assumed that the damage of the corrugated steel web box girder occurs at the torsional damage surface 4. The point of action of the resultant compressive force is selected on the torsional damage surface 4. The force conditions in all directions of the point of action of the resultant compressive force are analyzed to obtain the moment formula and torque formula at the point of action of the resultant compressive force. The obtained moment formula and torque formula are simplified and associated to obtain the relationship between the moment and torque at the point of action of the resultant compressive force.

[0024] As a specific implementation of the limit state analysis method of a corrugated steel web box girder provided by the present invention, please refer to Figures 1 to 9 , analyze the stress at the point of action of the combined compressive force, establish a local coordinate system at the point of action of the combined compressive force, and analyze the stress under different failure modes. x Axial force, y Axial forces and z The force in the axial direction, x The axial force includes the forces generated by the top plate 1, bottom plate 2, longitudinal reinforcement 5, and prestressed reinforcement 7. y The axial force includes the force generated by the transverse reinforcement 6. z The axial force includes the vertical force of the corrugated steel web 3 on the boundary of the torsional failure surface 4 .

[0025] For details, please refer to Figures 1 to 9 In the process of analyzing the point of action of the resultant compressive force, a three-dimensional local coordinate system is established at the point of action of the resultant compressive force. x Axial force, y Axial forces and z Analysis of the forces in the axial direction includes analysis of the forces acting on the top plate 1, the bottom plate 2, the longitudinal reinforcement 5, the prestressed tendons 7, the transverse reinforcement 6, the corrugated steel web 3, etc.

[0026] As a specific implementation of the limit state analysis method of a corrugated steel web box girder provided by the present invention, please refer to Figures 1 to 3 In the case of failure mode I (bending failure), when the torsion is relatively small, cracks first appear in the bending tension bottom plate 2, and develop to the two sides of the bottom plate 2, and spiral virtual cracks appear on the corrugated steel webs 3 on both sides. When the bending moment is large, the top surface is compressed and no cracks appear. A spiral crack appears between the top of the oblique crack on the side of the bottom plate 2 and the bottom of the oblique crack on the side of the top plate 1. A virtual boundary is connected along the direction of the spiral crack. The spiral crack of the bottom plate 2 and the extended dotted line of the virtual boundary on the two corrugated steel webs 3 form a twisted failure surface 4. When the stress of the bottom plate 2 steel bars reaches the tensile yield, the cracks develop rapidly and develop into failure mode I (bending failure). The compressive failure surface appears on the top surface, and the point of action of the compressive resultant force is on the top plate 1.

[0027] Under the limit state, the point of action of the resultant compressive force of the top plate 1 is located on the torsional failure surface 4. A stress analysis is performed on the point of action of the resultant compressive force, and a local three-dimensional coordinate system is established at the point of action of the resultant compressive force.

[0028] The pressure resultant force point xThe axial forces include: the force of the longitudinal steel bars 5 in the top plate 1, the force of the longitudinal steel bars 5 in the bottom plate 2, the force of the prestressed tendons 7, and the force of the top plate 1 (concrete) (the bottom plate 2 is out of service after being cracked under tension and does not generate any force). y The force in the axial direction is the sum of the transverse forces of the transverse reinforcement 6 in the top plate 1 and the transverse reinforcement 6 in the bottom plate 2. z The force in the axial direction is the sum of the vertical forces of the corrugated steel web 3 on the virtual boundary of the torsional failure surface 4.

[0029] The point of action of the combined pressure force on the top plate 1 is y The ultimate bending moment is obtained by calculating the bending moment of the axis M u , (1), Where: h z is the total height of the corrugated steel web box girder; h w is the height of corrugated steel web 3; h p It is the height from the prestressed tendons 7 of the bottom plate 2 to the upper end surface of the top plate 1; y′ s is the distance from the point of action of the combined force of the steel bars in the top plate 1 to the compression edge of the section, y s The distance from the position of the combined force application point behind the steel bars in the bottom plate 2 to the tensile edge of the section; y c is the distance from the point of action of the resultant force of the top plate 1 in the compression zone to the upper edge of the top plate 1 under compression; b The maximum distance between the outermost corrugated steel webs 3 on both sides; δ t is the thickness of the top plate 1, δ b is the thickness of the bottom plate 2, δ w is the thickness of the corrugated steel web 3; the crack angles of the top plate 1, bottom plate 2, left corrugated steel web 3, and right corrugated steel web 3 are α t , α b , α l , α r ; A′ s is the area of ​​top plate 1 reinforcement (including the upper flange of the steel beam), A s is the area of ​​the bottom plate 2 reinforcement (including the lower flange of the steel beam), A pis the area of ​​the prestressed tendon 7; f y is the yield strength of the longitudinal reinforcement 5; σ pu is the ultimate stress of the prestressed tendon 7; f w is the yield strength of the corrugated steel web 3.

[0030] The point of action of the combined pressure force on the top plate 1 is relative to x The shaft torque is calculated to obtain the limit torque T u , (2), Where: A sv1 is the area of ​​the single-leg transverse reinforcement 6 of the bottom plate 2; f yv is the yield strength of the transverse reinforcement 6; S It is the axial spacing of the transverse reinforcement 6 along the corrugated steel web box girder.

[0031] Assume that the crack angles on each surface of the corrugated steel web box girder are the same, that is, α = α l = α r = α b ， make A cor0 = bh w , A corⅠ = b(h z - y c - δ b / 2) , u cor0 = 2(h z + b) , substituting into formula 1 and formula 2, we get (3), (4), According to formula 4, we can get (5), Substituting formula 5 into formula 3, we get (6), In the formula, ζ ⅠDefined as the ratio of the effect of the axial reinforcement (longitudinal reinforcement 5 and prestressed reinforcement 7) and the corrugated steel web 3, (7), In formula 6, under the limit condition where only pure bending force acts, the torque T u =0, that is, only the bending moment acts, and the definition for z The ultimate moment bearing capacity under pure bending in the direction is obtained (8), In formula 6, the bending moment is assumed to be in the limit case where only pure torsion is applied. M u =0, that is, only torque acts, definition for x The ultimate torque bearing capacity under pure torsion in the direction is obtained (9), Substituting formula 8 and formula 9 into formula 6, we get (10).

[0032] As a specific implementation of the limit state analysis method of a corrugated steel web box girder provided by the present invention, please refer to Figures 4 to 6 In the case of failure mode II (torsional failure), when the torsion is relatively large and the bending moment is small, and the reinforcement of the longitudinal steel bars 5 of the top plate 1 is significantly less than that of the bottom plate 2, the tensile stress generated by the torque offsets the compressive stress generated by the positive bending moment on the top plate 1, and the longitudinal steel bars 5 of the top plate 1 reach the yield strength earlier than the longitudinal steel bars 5 of the bottom plate 2. Cracks are formed in the top plate 1 and expand to the corrugated steel webs 3 on both sides. Due to the yielding of the longitudinal steel bars 5 of the top plate 1, the oblique pressure surface produces a plastic hinge that rotates downward, and the concrete of the bottom plate 2 is compressed, developing into failure mode II (torsional failure), and the point of action of the resultant compressive force is selected on the bottom plate 2.

[0033] Under the limit state, the point of action of the resultant compressive force on the bottom plate 2 is located on the torsional failure surface 4. A stress analysis is performed on the point of action of the resultant compressive force, and a local three-dimensional coordinate system is established at the point of action of the resultant compressive force.

[0034] The pressure resultant force point x The forces acting in the axial direction include: the forces acting on the longitudinal reinforcement 5 in the top plate 1, the forces acting on the longitudinal reinforcement 5 in the bottom plate 2, the forces acting on the prestressed tendons 7, and the forces acting on the bottom plate 2 (concrete). y The force in the axial direction is the sum of the transverse forces of the transverse reinforcement 6 in the top plate 1 and the transverse reinforcement 6 in the bottom plate 2. z The force in the axial direction is the sum of the vertical forces of the corrugated steel web 3 on the virtual boundary of the torsional failure surface 4.

[0035] The point of action of the resultant compressive force on the bottom plate 2 is y The ultimate bending moment is obtained by calculating the bending moment of the axis M u , (11), The point of action of the resultant compressive force on the bottom plate 2 is relative to x The shaft torque is calculated to obtain the limit torque T u , (12), Assuming that the crack angles on each surface of the corrugated steel web box girder are the same, let α = α l = α r = α t , A′ corⅠ = b(h z - y c - δ t / 2) , substituting into formula 11 and formula 12, we get (13), (14), Refer to the simplified calculation process of failure mode I (bending failure), ζ ⅠI Defined as the ratio of the effect of the axial reinforcement (longitudinal reinforcement 5 and prestressed reinforcement 7) and the corrugated steel web 3 in failure mode II (torsion failure), (15), In the limit case where only pure bending force acts, the torque T u =0, that is, only the bending moment acts, and the definition for z The ultimate moment bearing capacity under pure bending in the direction is obtained (16), In the limit case where only pure torsion is applied, the bending moment M u =0, that is, only torque acts, definition for x The ultimate torque bearing capacity under pure torsion in the direction is obtained (17), According to formulas 11 to 17, the simplified derivation process is the same as that of failure mode I (bending failure) to obtain (18).

[0036] As a specific implementation of the limit state analysis method of a corrugated steel web box girder provided by the present invention, please refer to Figures 7 to 9 In the case of failure mode III (bending-torsion failure), when the torsion is relatively large and the thickness of the corrugated steel web 3 is relatively thin, when the direction of the principal tensile stress generated by the torque and the vertical shear force is consistent, cracks are formed on the side walls of the top plate 1 and the bottom plate 2, and extend to the plate surface of the top plate 1 and the bottom plate 2. The principal tensile stress directions on the top plate 1 and the bottom plate 2 are opposite, and the cracks on the side walls of the top plate 1 and the bottom plate 2 are suppressed or even compressed. One of the side walls of the top plate 1 and the bottom plate 2 is tensile, and the other side wall is compressed, which develops into failure mode III (bending-torsion failure). The point of action of the compressive force is selected on the corrugated steel web 3. At this time, due to the small bending moment, the side wall is y The bending bearing capacity of the shaft is easy to meet, but the z The bending moment of the shaft may exceed its bearing capacity, causing the shaft to bend. z The bending failure of the shaft should be considered. z The bending moment of the shaft is balanced.

[0037] Under the limit state, the point of action of the resultant compressive force of the corrugated steel web 3 is located on the torsional failure surface 4. A stress analysis is performed on the point of action of the resultant compressive force, and a local three-dimensional coordinate system is established at the point of action of the resultant compressive force.

[0038] The pressure resultant force point x The axial forces include: the force of the longitudinal steel bars 5 in the top plate 1, the force of the longitudinal steel bars 5 in the bottom plate 2, the force of the prestressed tendons 7, and the forces of the top plate 1 (concrete) and the bottom plate 2 (concrete) on the compression side. y The force in the axial direction is the sum of the transverse forces of the top plate 1 transverse reinforcement 6 and the bottom plate 2 transverse reinforcement 6. z The force in the axial direction is the sum of the vertical forces of the corrugated steel web 3 on the virtual boundary of the failure surface.

[0039] The point of action of the resultant compressive force on the corrugated steel web 3 is z The ultimate bending moment is obtained by calculating the bending moment of the axis M zu (The axial stiffness of the corrugated steel web 3 is not considered), and we get (19), Where: It is the area of ​​a single-leg transverse reinforcement 6 of the top plate 1.

[0040] The point of action of the resultant compressive force on the corrugated steel web 3 is relative tox The shaft torque is calculated to obtain the limit torque T u , (20), Assume that the crack angles on all sides of the corrugated steel web box girder are the same ，α = α r = α b = α t , A corⅡ = b ( h z - δ b ), A′ corⅡ = b ( h z - δ t ), substitute into formula 19 and formula 20, and we get (twenty one), (twenty two), Refer to the simplified calculation process of failure mode I (bending failure), ζ Ⅲ Defined as the ratio of the effect of the axial reinforcement (longitudinal reinforcement 5 and prestressed reinforcement 7) and the corrugated steel web 3 in failure mode III (bending-torsion failure), (twenty three), In the limit case where only pure bending force acts, the torque T u =0, that is, only the bending moment acts, and the definition for z The ultimate moment bearing capacity under pure bending in the direction is obtained (twenty four), In the limit case where only pure torsion is applied, the bending moment M u =0, that is, only torque acts, definition for x The ultimate torque bearing capacity under pure torsion in the direction is obtained (25), According to formula 19 to formula 25, the same simplified derivation process as the simplified calculation process of failure mode I (bending failure) is adopted. z There is no bending moment in the direction and the limit equilibrium equation when the compressive failure surface appears on the corrugated steel web 3 is: (26).

[0041] As a specific implementation of the limit state analysis method of a corrugated steel web box girder provided by the present invention, please refer to Figures 1 to 12 The bending-torsion failure envelope diagram is based on the ratio of the bending moment at the point of action of the combined compressive force to the ultimate bending moment under pure bending. x The ratio of the torque at the point of action of the combined pressure force to the limit torque under pure torsion is y The relationship between the bending moment and torque under the three failure modes is plotted into the same bending-torsion failure envelope diagram to obtain the failure curves under the three failure modes. The type of failure that occurs is determined based on the positions of the three sets of failure curves. y In the axial direction, the failure mode represented by the failure curve at the bottom occurs.

[0042] Formula 10 of failure mode Ⅰ (bending failure), formula 18 of failure mode Ⅱ (torsion failure), and formula 26 of failure mode Ⅲ (bending-torsion failure) are unified and derived. Formula 10, formula 18, and formula 26 are all used. M u , M u0 , T u , T u0 To indicate that, M u0 = , is the ultimate moment bearing capacity under pure bending, T u0 = , is the limit torque under pure torsion, and introduce r , r As a constant value, r It reflects the ratio of the longitudinal reinforcement in the top plate 1 to the total longitudinal reinforcement in the bottom plate 2. It is the product of the ratio of the effect of the longitudinal reinforcement in the top plate to the total longitudinal reinforcement in the section and the ratio of the effect of the transverse reinforcement to the corrugated steel web. (27), (28), Correspondingly, the formula 10 for failure mode I (bending failure) is simplified to (29), Correspondingly, the formula 18 for failure mode II (torsion failure) is simplified to (30), Correspondingly, the formula 26 for failure mode III (bending-torsion failure) is simplified to (31).

[0043] Establish a plane rectangular coordinate system, and draw the failure curves of the three failure modes represented by Formula 29 to Formula 31 into the same bending-torsion failure envelope diagram. T u / T u0 is the vertical axis, M u / M u0 The horizontal axis is the abscissa. In the bending-torsion failure envelope diagram, the failure curves of the three failure modes have a positional relationship. The failure curves of the three failure modes have an intersection in the bending-torsion failure envelope diagram. The failure curve represents the limit case of this failure mode. Therefore, when the section is damaged, under the same horizontal axis, the failure mode represented by the failure curve at the bottom will occur first. The three failure curves are solved jointly to obtain the coordinates of the intersection. According to the relative positions of the three curves, the bending-torsion failure envelope diagram is divided into three cases: Case 1, please refer to Fig.10 , According to the intersection of the failure curve, failure mode II (torsion failure) and failure mode III (bending-torsion failure) will not occur. T u / T u0 ≤1.0, combined with formula 29 and formula 31, the horizontal coordinate of the intersection of the failure curves of failure mode Ⅰ (bending failure) and failure mode Ⅲ (bending-torsion failure) is ,but Failure mode III (bending-torsion failure) occurs. Failure mode I (bending failure) occurs.

[0044] Case 2, please refer to Fig.11 , , it can be seen that in failure mode III (bending-torsion failure) , combining formula 30 and formula 31, we can get the horizontal coordinate of the intersection of the curves of failure mode II (torsion failure) and failure mode III (bending-torsion failure) is ; Combining Formula 29 and Formula 31, we can get the horizontal coordinate of the intersection of the failure curves of failure mode Ⅰ (bending failure) and failure mode Ⅲ (bending-torsion failure) is ,but Failure mode II (torsion failure) occurs. Failure mode III (bending-torsion failure) occurs. Failure mode I (bending failure) occurs.

[0045] Case 3, please refer to Fig.12 , :Failure mode III (bending-torsion failure) , combining formula 29 and formula 30, we get the intersection of the failure curves of failure mode Ⅰ (bending failure) and failure mode Ⅱ (torsion failure) as ,but Failure mode II (torsion failure) occurs. Failure mode I (bending failure) occurs.

[0046] Based on the same inventive concept, an embodiment of the present application also provides a terminal. A specific implementation of a terminal is now described, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of any of the methods described above when executing the computer program.

[0047] Specifically, in this embodiment, the terminal may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal may include, but is not limited to, a processor and a memory, and may include more components than the above structure, or a combination of certain components, or different components. For example, the terminal may also include input and output devices, network access devices, buses, etc.

[0048] The processor may be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, field programmable gate arrays, or other programmable logic device discrete gates or discrete hardware components of transistor logic devices. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor. The memory may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. The memory may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card, or a flash memory card equipped on the terminal.

[0049] Based on the same inventive concept, an embodiment of the present application also provides a computer-readable storage medium. A specific implementation of a computer-readable storage medium is now described. The computer-readable storage medium stores a computer program, which is characterized in that when the computer program is executed by a processor, the steps of any method described above are implemented.

[0050] Specifically, each functional unit in each embodiment of the present invention may be integrated into a processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of a software functional unit. If the integrated module or unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium.

[0051] Based on this understanding, the present invention implements all or part of the processes in the above-mentioned implementation method, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above-mentioned identification method can be implemented.

[0052] The above are only preferred embodiments of the present invention and are 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 in the protection scope of the present invention.

Claims

1. A method for analyzing the limit state of a corrugated steel web box girder, characterized in that: The steps include: S1. Three failure modes of the ultimate state of the corrugated steel web box girder are introduced, namely failure mode I (bending failure), failure mode II (torsion failure) and failure mode III (bending-torsion failure); S2. Calculate the bending moment formula and torque formula under the three failure modes respectively; S3. Unify the bending moment formula and torque formula under the three failure modes to obtain the bending-torsion failure envelope diagram; S4. Determine the type of failure mode produced under different conditions based on the obtained bending-torsion failure envelope diagram.

2. A method for analyzing the limit state of a corrugated steel web box girder according to claim 1, characterized in that: In the calculation process, the section formed after the destruction of the corrugated steel web box girder is defined as the torsional failure surface. The points of action of the combined compressive force are selected on the torsional failure surface, and the forces at the points of action of the combined compressive force are analyzed to obtain the bending moment formula and torque formula at the points of action of the combined compressive force.

3. A method for analyzing the limit state of a corrugated steel web box girder as claimed in claim 2, characterized in that: In the case of failure mode I (bending failure), when the stress of the bottom plate reinforcement reaches the tensile yield, the cracks quickly develop into failure mode I (bending failure), and the point of action of the compressive force is on the top plate.

4. The method for analyzing the limit state of a corrugated steel web box girder according to claim 2, characterized in that: In the case of failure mode II (torsional failure), the tensile stress generated by the torque offsets the compressive stress generated by the positive bending moment in the top plate. The longitudinal reinforcement of the top plate reaches the yield strength earlier than the longitudinal reinforcement of the bottom plate. Cracks are formed in the top plate and extend to the corrugated steel webs on both sides. Due to the yielding of the longitudinal reinforcement of the top plate, the oblique compression surface produces a plastic hinge that rotates downward, and the bottom plate concrete is compressed, developing into failure mode II (torsional failure), and the point of action of the resultant compressive force is on the bottom plate.

5. The method for analyzing the limit state of a corrugated steel web box girder according to claim 2, characterized in that: In the case of failure mode III (bending-torsion failure), the directions of the principal tensile stresses generated by the torque and the vertical shear force are consistent, cracks are formed on the side walls of the top and bottom plates, and extend to the plate surfaces of the top and bottom plates. The directions of the principal tensile stresses on the top and bottom plates are opposite, and the cracks on the side walls of the top and bottom plates are suppressed. One of the side walls of the top and bottom plates is subjected to tension and the other is subjected to compression, developing into failure mode III (bending-torsion failure), and the point of action of the resultant compressive force is on the corrugated steel web.

6. A method for analyzing the limit state of a corrugated steel web box girder according to claim 2, characterized in that: Analyze the stress at the point of action of the combined compressive force, establish a local coordinate system at the point of action of the combined compressive force, and analyze the stress under different failure modes. x Axial force, y Axial forces and z The force in the axial direction, x The axial forces include the forces generated by the top plate, bottom plate, longitudinal reinforcement, and prestressed tendons. y The axial force includes the force generated by the transverse reinforcement. z The axial force includes the vertical force acting on the corrugated steel web at the boundary of the torsional failure surface.

7. The method for analyzing the limit state of a corrugated steel web box girder according to claim 1, characterized in that: The bending-torsion failure envelope diagram is based on the ratio of the bending moment at the point of action of the combined compressive force to the ultimate bending moment under pure bending. x The ratio of the torque at the point of action of the combined pressure force to the limit torque under pure torsion is y Axis, the relationship between bending moment and torque under the three failure modes are plotted into the same bending-torsion failure envelope diagram, and the failure curves under the three failure modes are obtained. The type of failure that occurs is determined according to the positions of the three groups of failure curves.

8. The method for analyzing the limit state of a corrugated steel web box girder according to claim 7, characterized in that: exist y In the axial direction, the failure mode represented by the failure curve at the bottom occurs.

9. A terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method described in any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that When the computer program is executed by a processor, the steps of the method described in any one of claims 1 to 8 are implemented.

Images