Design method for accurately considering rigidity of flat node of center pillar end plate of portal rigid frame

Abstract

The invention discloses a design method for accurately considering the rigidity of a flat node of a center pillar end plate of a portal rigid frame, which comprises the following steps of: 1, modeling the rigid frame by adopting two-dimensional modeling software to obtain a model; secondly, for the model meeting the index requirement and the component internal force requirement, internal force at beam-column joints in the rigid frame is extracted, and the end plate thickness and bolt connection are designed; 3, according to the beam column node and the end plate thickness, the beam column rotation rigidity and the steel beam line rigidity are obtained through calculation through a beam column rotation rigidity algorithm and a steel beam line rigidity algorithm; 4, according to the parameter R / ib = kb, judging whether the node is restrained by an ideal rigid connection node or not, and determining whether the design is completed or not; wherein ib is steel beam line rigidity, R is beam column rotation rigidity, and kb is beam column joint constraint rigidity. The invention discloses a design method which is high in economical efficiency, excellent in rigid connection structure rigidity and capable of accurately considering the rigidity of a horizontal joint of a center pillar end plate of a portal rigid frame.

Description

Technical Field

[0001] The invention relates to the technical field of portal frame structures, and in particular to a design method for accurately considering the horizontal node stiffness of a column end plate in a portal frame. Background Art

[0002] At present, portal frame structural systems are widely used in industrial plant projects, and their cost is economical among many steel structure systems. The application of end plate nodes in multi-span portal frame columns is also common. The existing technology stipulates the design of portal steel nodes, and the beam-column connection form is as follows: Figure 1-Figure 4 As shown in the figure, the end plate is placed vertically, horizontally and obliquely, and the force analysis includes the design of connecting bolts, determination of end plate thickness, verification of shear stress in the node domain and the web strength of the member at the end plate bolt. On the basis of the node meeting the above force requirements, the rotation stiffness of the rigid frame beam column determines whether the node has achieved the ideal rigid connection. However, on the basis of meeting the internal force analysis, in order to meet the structural requirements, the thickness of the web in the node domain is increased or oblique stiffening ribs are added in the node setting of the horizontal connection of the beam and column. When the overall indicators and node internal forces meet the requirements, the structure increases the cost, resulting in a decrease in the economy of the portal rigid structure. Summary of the invention

[0003] The present invention overcomes the shortcomings of the prior art and provides a design method which has high economy, excellent rigid connection structure rigidity and can accurately consider the horizontal node rigidity of the end plate of the central column of the portal frame.

[0004] To achieve the above object, the technical solution adopted by the present invention is: a design method for accurately considering the horizontal node stiffness of the end plate of the column in the portal frame, comprising the following steps: Step 1, using two-dimensional modeling software to model the rigid frame to obtain a model; Step 2: For the model that meets the index requirements and the component internal force requirements, extract the internal force at the beam-column node in the rigid frame to design the end plate thickness and bolt connection; Step 3, according to the beam-column node and the end plate thickness, the beam-column rotation stiffness and the steel beam linear stiffness are calculated by the beam-column rotation stiffness algorithm and the steel beam linear stiffness algorithm respectively; Step 4: According to R / i b = k b Parameters, determine whether it is constrained by an ideal rigid node and decide whether the design is complete; among them, i b is the linear stiffness of the steel beam, R is the beam-column rotational stiffness, k b is the beam-column joint constraint stiffness.

[0005] In a preferred embodiment of the present invention, in step 4, it is determined that R / i b = k b The relationship with 25, i b is the linear stiffness of the steel beam, R is the beam-column rotational stiffness, k b is the beam-column node constraint stiffness; When R / i b = k b When ≥25, it can be determined as an ideal rigid joint constraint and the design is completed; When R / i b = k b When ≤25, it is a semi-rigid semi-hinge node. In the model, the stiffness coefficient a= is added to the beam-column node. k b / 25, review the model, that is, reduce the node stiffness of the beam-column constraints in the model with a reduction factor of a. Set this parameter and calculate. When the result meets the index requirements and component internal force requirements specified in the specification, the design is completed.

[0006] In a preferred embodiment of the present invention, the index requirements include displacement, deflection, and width-to-thickness ratio; the internal force of the component includes the beam-column stress ratio.

[0007] Specifically, the displacement, deflection and width-to-thickness ratio required by the indicators and the beam-to-column stress ratio including the internal forces of the components meet the requirements stipulated in the technical implementation standards in the existing technology (the current "Technical Specifications for Portal Frame Light Steel Structures of Houses").

[0008] In a preferred embodiment of the present invention, the beam-column rotation stiffness algorithm is: R=R1*R2 / (R1+R2), where: R1=Gh1d c t p +Ed b A st cos 2 αsinα; R2=6EI e h1 2 / 1.1e f 3 ; G is the shear modulus of steel, E is the elastic modulus of steel, h1 is the distance between the centers of the beam end flange plates, d c is the width between the node domain plates, t p is the web thickness of the node domain beam, d b is the height between the node domain plates, A stis the total cross-sectional area of ​​the two oblique stiffeners, α is the inclination angle of the oblique stiffeners; R1 is the stiffness corresponding to the shear deformation of the node domain; R2 is the bending stiffness of the connection, including the stiffness corresponding to the end plate bending, bolt tension and column flange bending; I e is the moment of inertia of the end plate, e f It is the distance from the center of the bolt of the overhanging part of the end plate to the outer edge of its stiffening rib.

[0009] In a preferred embodiment of the present invention, the linear stiffness algorithm of the steel beam is: i b =EI b / l b ,i b is the beam line stiffness; E is the elastic modulus of the steel, I b is the average section inertia moment of the frame beam span, and the average is taken for the left and right beams of the node; l b is the span of the frame beam, and the average span on the left and right sides of the node is taken.

[0010] In a preferred embodiment of the present invention, in step 1, the beam-column connection node in the rigid frame is a rigid connection.

[0011] In a preferred embodiment of the present invention, in step 4, when R / i b = k b When ≤25, the semi-rigid and semi-hinge nodes and beam-column nodes consider the stiffness coefficient a, a= k b / 25, reduce the node stiffness and review the model. If the calculation results do not meet the design requirements, adjust the local beam-column sections and repeat the above process. Compare the steel consumption with the calculation results of adding oblique stiffeners or thickening the node domain web, and select a more economical solution while meeting the node stiffness.

[0012] In a preferred embodiment of the present invention, when k b ≥10, the model does not involve the adjustment of the cross-section of the beam and column in the rigid frame after it is brought back, and the design requirements can be met; k b When it is less than 10, review the original model or design according to the rocking column.

[0013] In a preferred embodiment of the present invention, the component internal force requirement includes: the component stress ratio is less than 1 under the action of the design load.

[0014] In a preferred embodiment of the present invention, a computer-readable storage medium is provided for a design method for accurately considering the stiffness of the horizontal node of the end plate of a column in a portal frame, on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the steps of the design method for accurately considering the stiffness of the horizontal node of the end plate of a column in a portal frame are implemented.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a design method that is highly economical, has excellent rigidity of rigid connection structure, and can accurately consider the rigidity of the node where the end plate of the column in the portal frame is placed flat. For the beam-column connection node where the end plate of the column in the portal frame is placed flat, when the beam-column connection meets the force requirements, the actual constraint rigidity of the node is determined according to the ratio of rotational rigidity to linear rigidity, and then the overall model is reviewed, without having to meet the structural requirements to achieve the ideal rigid connection. This method can reduce the amount of steel used in the beam-column node, and on the basis of ensuring safety, the node structure is simple and easy to construct.

[0016] (1) Simple structure: There is no need to change the web thickness of the node area or add oblique stiffeners in the node area, which reduces the number of welds in the node area and facilitates construction; (2) Economical: Compared with the ideal rigid connection structural requirements, the steel consumption is low and has certain economical efficiency; (3) Applicability: It is applicable to the design of intermediate nodes of multi-span portal frames. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0018] Figure 1 It is a schematic diagram of the structure of the end plate placed vertically in the prior art; Figure 2 It is a schematic diagram of the structure of the flat end plate in the prior art; Figure 3 It is a schematic diagram of the structure in which the end plate is placed obliquely in the prior art; Figure 4 It is a structural schematic diagram of the end plate splicing in the prior art; Figure 5 It is a flow chart of a design method of the present invention that accurately considers the stiffness of the horizontal node of the column end plate in the portal frame; Figure 6 The invention is a method for accurately considering the horizontal node stiffness of the center column end plate of the portal frame designed by the center column end plate horizontal node structure Figure 1 .

[0019] Figure 7 The invention is a method for accurately considering the horizontal node stiffness of the center column end plate of the portal frame designed by the center column end plate horizontal node structure Figure 2 ; Where h1 is the distance between the centers of the beam end flange plates; d b is the height between the plates in the node domain; t p is the web thickness of the node domain beam; d c is the width between the node domain plates; e f It is the distance from the center of the bolt of the overhanging part of the end plate to the outer edge of its stiffening rib; α is the inclination angle of the inclined stiffening rib. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0021] The term "and / or" is only a description of the association relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " generally indicates that the related objects are in an "or" relationship. Embodiment 1

[0022] To achieve the above purpose, a design method for accurately considering the horizontal node stiffness of the end plate of the portal frame column includes the following steps: Step 1: Use two-dimensional modeling software to model the rigid frame to obtain a model; the beam-column connection nodes in the rigid frame are rigid connections.

[0023] Step 2: For the model that meets the index requirements and the internal force requirements of the components, the internal forces at the beam-column nodes in the rigid frame are extracted to design the end plate thickness and bolt connection. Specifically, in a preferred embodiment of the present invention, the index requirements include displacement, deflection, and width-to-thickness ratio; the component internal force includes the beam-to-column stress ratio. Specifically, the displacement, deflection and width-to-thickness ratio required by the index and the beam-to-column stress ratio included in the component internal force meet the requirements specified in the technical implementation standards in the prior art (the current "Technical Specifications for Portal Frame Lightweight Steel Structures").

[0024] Step three, according to the beam-column node and the end plate thickness, the beam-column rotation stiffness and the steel beam linear stiffness are calculated respectively by the beam-column rotation stiffness algorithm and the steel beam linear stiffness algorithm.

[0025] Specifically, the beam-column rotation stiffness algorithm is: R=R1*R2 / (R1+R2), where: R1=Gh1d c t p +Ed b A st cos 2 αsinα; R2=6EI e h1 2 / 1.1e f 3 ; Where G is the shear modulus of steel (N / mm 2 ); E is the elastic modulus of steel (N / mm 2 );I e is the moment of inertia of the end plate (mm 4 ); h 1 is the distance between the centers of the beam end flange plates (mm); d c is the width between the plates in the node domain (mm); t p is the web thickness of the node domain beam (mm); d b is the height between the plates in the node domain (mm); e f is the distance from the center of the bolt of the extended part of the end plate to the outer edge of the stiffening rib (mm); beam line stiffness i b =EI b / l b ; E is the elastic modulus of steel (N / mm 2 );I b is the average section inertia moment of the frame beam span (mm 4 ), the average of the left and right beams of the node is taken; l b A is the span of the frame beam (mm), and the average span of the left and right spans of the node is taken; st is the total cross-sectional area of ​​the two oblique stiffeners, α is the inclination angle of the oblique stiffeners; R1 is the stiffness corresponding to the shear deformation of the node domain; R2 is the bending stiffness of the connection, including the stiffness corresponding to the bending of the end plate, the tension of the bolts and the bending of the column flange; A st is the total cross-sectional area of ​​the two oblique stiffeners, α is the inclination angle of the oblique stiffeners; R1 is the stiffness corresponding to the shear deformation of the node domain; R2 is the bending stiffness of the connection, including the stiffness corresponding to the end plate bending, bolt tension and column flange bending; I e is the moment of inertia of the end plate, e f The distance from the center of the bolt of the extended part of the end plate to the outer edge of the stiffener Specifically, the linear stiffness algorithm of the steel beam is: i b =EI b / l b ,i b is the beam line stiffness; E is the elastic modulus of the steel, I bis the average section inertia moment of the frame beam span, and the average is taken for the left and right beams of the node; l b is the span of the frame beam, and the average span on the left and right sides of the node is taken.

[0026] Step 4: Determine R / i b = k b The relationship with 25, i b is the linear stiffness of the steel beam, R is the beam-column rotational stiffness, k b is the beam-column node constraint stiffness; When R / i b = k b When ≥25, the ideal beam-column rotation stiffness and steel beam linear stiffness requirements are met, and the design is completed; When R / i b = k b When ≤25, it is a semi-rigid semi-hinge node. In the model, the stiffness coefficient a= is added to the beam-column node. k b / 25, review the model, that is, reduce the node stiffness of the beam-column constraints in the model with a reduction factor of a. Set this parameter and calculate. When the result meets the index requirements and component internal force requirements specified in the specification, the design is completed. Embodiment 2

[0027] Furthermore, based on the first embodiment, in step 4, when R / i b = k b When ≤25, the semi-rigid and semi-hinge nodes and beam-column nodes consider the stiffness coefficient a, a= k b / 25, reduce the node stiffness and review the model. If the calculation results do not meet the design requirements, adjust the local beam-column sections and repeat the above process. Compare the steel consumption with the calculation results of adding oblique stiffeners or thickening the node domain web, and select a more economical solution while meeting the node stiffness. Embodiment 3

[0028] Furthermore, on the basis of the first or second embodiment, when k b ≥10, the model does not involve the adjustment of the cross-section of the beam and column in the rigid frame after it is brought back, and the design requirements can be met; k b When it is less than 10, the original model is reviewed, or the swing column design is performed according to the prior art. Embodiment 4

[0029] On the basis of Example 1, Example 2 or Example 3, a computer-readable storage medium is provided for a design method that accurately considers the stiffness of the horizontal node of the end plate of a column in a portal frame, on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the steps of the design method that accurately considers the stiffness of the horizontal node of the end plate of a column in a portal frame are implemented.

[0030] Working principle: The present invention discloses a design method that can accurately consider the stiffness of the node where the end plate of the column in the portal frame is placed flat. For the beam-column connection node where the end plate of the column in the portal frame is placed flat, when the beam-column connection meets the force requirements, the actual constraint stiffness of the node is determined according to the ratio of rotational stiffness to linear stiffness, and then the overall model is reviewed, without having to meet the structural requirements to achieve the ideal rigid connection. This method can reduce the amount of steel used in the beam-column node, and on the basis of ensuring safety, the node structure is simple and easy to construct. There is no need to replace the thickness of the node web or add oblique stiffening ribs in the node area, which reduces the welds in the node area and facilitates construction; compared with the structural requirements of the ideal rigid connection, the amount of steel used is low and has a certain economy; it is applicable to the design of intermediate nodes of multi-span portal frames.

[0031] Based on the ideal embodiment of the present invention, through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A design method that accurately considers the horizontal node stiffness of the end plate of the portal frame column, characterized in that: The following steps are involved: Step 1, using two-dimensional modeling software to model the rigid frame to obtain a model; Step 2: for the model that meets the index requirements and the component internal force requirements, extract the internal force at the beam-column node in the rigid frame to design the end plate thickness and bolt connection; Step 3, according to the beam-column node and the end plate thickness, the beam-column rotation stiffness and the steel beam line stiffness are calculated by the beam-column rotation stiffness algorithm and the steel beam line stiffness algorithm respectively; Step 4: According to R / i b = k b Parameters, determine whether it is constrained by an ideal rigid node and decide whether the design is complete; among them, i b is the linear stiffness of the steel beam, R is the beam-column rotational stiffness, k b is the beam-column joint constraint stiffness.

2. According to claim 1, a design method for accurately considering the horizontal node stiffness of the end plate of the portal frame center column is characterized by: In step 4, determine R / i b = k b The relationship with 25, i b is the linear stiffness of the steel beam, R is the beam-column rotational stiffness, k b is the beam-column node constraint stiffness; When R / i b = k b When ≥25, it can be determined as an ideal rigid joint constraint and the design is completed; When R / i b = k b When ≤25, it is a semi-rigid semi-hinge node. In the model, the stiffness coefficient a= is added to the beam-column node. k b / 25, review the model, that is, reduce the node stiffness of the beam-column constraints in the model with a reduction factor of a. Set this parameter and calculate. When the result meets the specified index requirements and component internal force requirements, the design is completed.

3. A design method for accurately considering the horizontal node stiffness of the end plate of the portal frame center column according to claim 2, characterized in that: The index requirements include displacement, deflection, and width-to-thickness ratio; the internal forces of the components include the beam-to-column stress ratio.

4. A design method for accurately considering the horizontal node stiffness of the end plate of the portal frame center column according to claim 2, characterized in that: The beam-column rotation stiffness algorithm is: R=R1*R2 / (R1+R2), where: R1=Gh1d c t p +Ed b A st cos 2 αsinα; R2=6EI e h1 2 / 1.1e f 3 ; G is the shear modulus of steel, E is the elastic modulus of steel, h1 is the distance between the centers of the beam end flange plates, d c is the width between the node domain plates, t p is the web thickness of the node domain beam, d b is the height between the node domain plates, A st is the total cross-sectional area of ​​the two oblique stiffeners, α is the inclination angle of the oblique stiffeners; R1 is the stiffness corresponding to the shear deformation of the node domain; R2 is the bending stiffness of the connection, including the stiffness corresponding to the end plate bending, bolt tension and column flange bending; I e is the moment of inertia of the end plate, e f It is the distance from the center of the bolt of the overhanging part of the end plate to the outer edge of its stiffening rib.

5. A design method for accurately considering the horizontal node stiffness of the end plate of the portal frame center column according to claim 4, characterized in that: The steel beam linear stiffness algorithm is: i b =EI b / l b ,i b is the beam line stiffness; E is the elastic modulus of the steel, I b is the average section inertia moment of the frame beam span, and the average is taken for the left and right beams of the node; l b is the span of the frame beam, and the average span on the left and right sides of the node is taken.

6. A design method for accurately considering the horizontal node stiffness of the end plate of the portal frame center column according to claim 5, characterized in that: In step one, the beam-column connection nodes in the rigid frame are rigidly connected.

7. A design method for accurately considering the horizontal node stiffness of the end plate of the portal frame center column according to claim 6, characterized in that: In step 4, when R / i b = k b When ≤25, the semi-rigid and semi-hinge joint and the beam-column joint consider the stiffness coefficient a, a= k b / 25, reduce the node stiffness and review the model. If the calculation results do not meet the design requirements, adjust the local beam-column sections and repeat the above process. Compare the steel consumption with the calculation results of adding oblique stiffeners or thickening the node domain web, and select a more economical solution while meeting the node stiffness.

8. A design method for accurately considering the horizontal node stiffness of the end plate of the portal frame center column according to claim 7, characterized in that: when k b ≥10, the model does not involve the adjustment of the cross-section of the beam and column in the rigid frame after it is brought back, and the design requirements can be met; k b When it is less than 10, review the original model or design according to the rocking column.

9. A design method for accurately considering the horizontal node stiffness of the end plate of the portal frame center column according to claim 8, characterized in that: The component internal force requirements include: the component stress ratio is less than 1 under the design load.

10. A computer-readable storage medium for accurately considering the design method of the horizontal node stiffness of the end plate of the portal frame center column, wherein a computer program / instruction is stored, characterized in that: When the computer program / instructions are executed by a processor, the steps of the design method for accurately considering the horizontal node stiffness of the column end plate in the portal frame as described in any one of claims 1-9 are implemented.

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