A planar design method for column-removed factory buildings considering spatial effects

Abstract

The present invention discloses a planar design method for a plant structure with removed columns that takes spatial effects into consideration. The method is characterized in that a method of adding horizontal concentrated forces to the tops of columns of the removed column frame and the adjacent frame frames of the removed columns is adopted to consider the spatial effects of the plant under wind loads. The design of the plant frame with removed columns specifically includes: designing a standard frame frame, calculating the displacement of the column tops, the lateral stiffness of the frame after removing the columns and the additional concentrated forces at the column tops, verifying the frame with removed columns, completing the design of the frame with removed columns, and finally completing the design of the adjacent frame frames of the removed columns. Compared with the prior art, the present invention has the characteristics of accurately reflecting the spatial effects of the plant structure with removed columns due to the difference in lateral stiffness based on the stress characteristics of the plant structure with removed columns, thereby more accurately reflecting the actual stress states of the standard frame, the removed column frame, and the adjacent frame frames of the removed columns, while having the simple and efficient characteristics of the planar analysis method.

Description

Technical Field

[0001] The present invention relates to the technical field of architectural engineering design, in particular to a planar design method for a column-removing factory building structure taking spatial effects into consideration. Background Art

[0002] Due to the demands of factory production processes, steel structure factories often require the removal of columns to create large, locally large spaces. Conventional steel structure factories have uniform column spacing and uniform rigidity across their frames. Forces along the building span, i.e., the horizontal direction, are primarily in-plane, so planar analysis is employed for frame design. The rigidity of the frame removed in a factory with removed columns differs significantly from that of standard frames, resulting in a significant spatial effect, which significantly influences the design of the frame cross-section.

[0003] At present, the spatial effect under wind load is mainly considered, and there are three main design treatment methods for column-removal frames:

[0004] 1) Spring supports are used for the support beams at the column removal position to take into account the vertical stiffness of the support beams.

[0005] 2) Expanded frame method: model the column-drawn frame and the standard frame at the same time, set a virtual rigid chain rod between the two frames, and use the chain rod to coordinate the deformation relationship between the frames.

[0006] 3) Allocate the load according to the stiffness. Distribute the horizontal load according to the lateral stiffness of the frame. Define the horizontal load distribution coefficient to amplify or reduce the load borne by the frame, thereby completing the design of the standard frame and the column-drawn frame.

[0007] The first method mentioned above only considers the vertical stiffness of the joists and fails to account for the spatial effects of the factory building. The forces on the column-drawn truss frame differ significantly from the actual forces, so it is not recommended. The second method is based on the consistent deformation of the column tops of the column-drawn truss frame and the standard truss frame, and takes into account the spatial coordination of the roof. In actual design, under the condition of a certain load, the relative stiffness of the two trusses needs to be reasonably adjusted. The trial calculation workload is large, and there is a possibility that the stiffness of the column-drawn truss frame is too weak and the standard truss frame is too strong, resulting in an uneconomical frame design. The third method, which considers load distribution solely based on the relative stiffness of standard and truss-withdrawn columns, is incomplete. The reason is that the deformation of a truss-withdrawn plant is related not only to stiffness but also to the actual load distribution. This can lead to situations where a truss-withdrawn column has less stiffness than a standard truss, but because it actually carries less wind load (the wind load within the truss-withdrawn column is directly transmitted to adjacent trusses through wall framing components and does not act on the truss-withdrawn column), the deformation of the adjacent truss, ignoring spatial effects, is actually greater than that of the truss-withdrawn column. However, due to the spatial effects of the roof, the horizontal deformation of the column tops between the two trusses tends to be consistent, resulting in the truss-withdrawn column bearing not only its own actual wind load, but also the additional horizontal load from the roof (in the same direction as the wind load). This method fails to account for this situation and may result in an unsafe frame design. Furthermore, the forces reflecting spatial effects are primarily transmitted through roof components and are not simply multiplied by a coefficient across the entire height of the frame.

[0008] Due to the difference in stiffness between the trusses of a truss-type plant with a column-removed design and standard trusses, the plant structure exhibits significant spatial effects. Existing planar design methods cannot accurately account for these spatial effects. Steel structure plant design is generally governed by wind loads or crane loads, and the spatial effects of crane loads are not currently considered (to protect the frame design). Under wind loads, the spatial effects on the truss-type plant frame can be both beneficial and detrimental, and they significantly impact the cross-sectional design of the truss-type plant frame and its adjacent truss frames. Summary of the Invention

[0009] The purpose of the present invention is to provide a plan design method for the structure of a column-removed factory building that takes into account spatial effects and is designed to address the deficiencies of the existing technology. The method adopts a method of adding horizontal concentrated forces to the column tops of the column-removed frame and the column-adjacent frame. Based on the principle that the column top deformations of the column-removed frame and the standard frame are basically consistent, the spatial effects of the factory building are taken into account, and the internal forces and deformations of the column-removed frame and the column-adjacent frame are accurately calculated. This method can, based on the stress characteristics of the column-removed factory building, more accurately reflect the spatial effects caused by the lateral stiffness differences of the column-removed factory building in plane analysis, thereby more accurately reflecting the actual stress states of the standard frame, the column-removed frame, and the column-adjacent frame, while having the simplicity and high efficiency of the plane analysis method.

[0010] The specific technical solution for achieving the purpose of the present invention is: a planar design method for a column-removed factory building structure that takes into account spatial effects. The method is characterized by adding horizontal concentrated forces to the tops of the column frames of the column-removed frame and the column tops of the adjacent column frames, taking into account the spatial effects of the factory building under wind loads. The specific process of the column-removed factory building frame design is as follows:

[0011] 1) Design standard frame using plane modeling analysis method;

[0012] 2) Calculate the column top displacement △1 of the standard frame under wind load;

[0013] 3) The cross section of the column-removed truss frame is based on the cross section of the standard truss frame. Some columns are removed and only vertical springs are set at the column-removed position to consider the vertical stiffness of the joist. The vertical and horizontal loads are input according to the actual loaded area, and the column top displacement △2 under the action of the wind load is calculated;

[0014] 4) By inputting the unit concentrated force at the top of the column of the rigid frame, the lateral stiffness K1 of the rigid frame after the column is removed is obtained;

[0015] 5) Input additional concentrated force at the top of the column frame of the withdrawn column truss in step 3), that is, wind load condition, so that the displacement of the withdrawn column truss frame is consistent with the displacement of the standard truss frame. The additional concentrated force is: F1=(△1-△2)K1;

[0016] 6) Verify the column-drawing frame and complete the design of the column-drawing frame;

[0017] 7) The vertical load and horizontal load of the adjacent frame of the column are input according to the actual load-bearing area, and an additional concentrated force F2 is applied to the column top to complete the design of the adjacent frame of the column. When the column spacing on both sides of the column is equal, F2=-F1 / 2; when the column spacing on both sides of the column is not equal, F2=-d1 / (d1 +d2)F1; where d2 is the column spacing between the current frame and the column frame.

[0018] Compared with the prior art, the present invention takes into account the spatial effect of the factory building by adding horizontal concentrated force loads to the column tops of the column-removed frame and the column tops of the frame adjacent to the column-removed frame. It can more accurately reflect the spatial effect of the column-removed factory building. According to the stress characteristics of the column-removed factory building, the spatial effect of the column-removed factory building caused by the lateral stiffness difference can be more accurately reflected in the plane analysis, thereby more accurately reflecting the actual stress state of the standard frame, the column-removed frame, and the frame adjacent to the column-removed frame, and at the same time has the simplicity and high efficiency characteristics of the plane analysis method. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the three types of factory building frames. DETAILED DESCRIPTION

[0020] This paper mainly focuses on the structure of a plant with removed columns and proposes a plant plane design method that takes into account spatial effects. This plane analysis method is based on the following basic assumptions:

[0021] 1. The column spacing of the plant is basically uniform, and only some columns are removed. The overall lateral stiffness of the plant mainly depends on the standard frame. The column top displacement of the removed column frame is the same as that of the standard frame.

[0022] 2. The vertical load of the factory building does not consider the spatial effect, but only the spatial effect under the action of wind load. Crane load, earthquake effect, etc. are still calculated according to conventional rigid frame.

[0023] See Figure 1 , the factory building frames are divided into three categories: standard frame, column-drawn frame, and column-adjacent frame. Based on the above assumptions, the plane modeling analysis method is adopted to first complete the design of the standard frame. Then, based on the principle that the column top displacements of the column-drawn frame and the standard frame are equal under wind load, the factory building space effect is equivalent to the additional concentrated force at the column top, which acts on the column-drawn frame and the column-adjacent frame respectively, and the design of the column-drawn frame and the column-adjacent frame is completed.

[0024] The specific implementation process of the column-removing factory building rigid frame design of the present invention is as follows (the following analysis adopts plane modeling analysis):

[0025] 1) Design standard frame according to conventional plane analysis method;

[0026] 2) Calculate the column top displacement △1 of the standard frame under wind load;

[0027] 3) The cross section of the column-removed truss frame is based on the cross section of the standard truss frame. Some columns are removed and only vertical springs are set at the column-removed position to consider the vertical stiffness of the joist. The vertical and horizontal loads are input according to the actual loaded area, and the column top displacement △2 under the action of the wind load is calculated;

[0028] 4) By inputting the unit concentrated force at the top of the column of the rigid frame, the lateral stiffness K1 of the rigid frame after the column is removed is obtained;

[0029] 5) Input additional concentrated force (wind load condition) at the top of the column of the withdrawn column frame in step 3 to make the displacement of the withdrawn column frame consistent with the displacement of the standard frame. The magnitude of the additional concentrated force is F1=(△1-△2)K1;

[0030] 6. Check the column-drawing frame and complete the design of the column-drawing frame;

[0031] 7. The vertical and horizontal loads of the adjacent trusses are input based on the actual loaded area, and an additional concentrated force F2 is applied to the column tops. When the column spacing on both sides of the truss is equal, use F2 = -F1 / 2; when the column spacing on both sides of the truss is unequal, use F2 = -d1 / (d1 +d2)F1 (d2 is the column spacing between the current truss and the truss with the column removed, and d1 is the column spacing between the truss with the column removed and the truss on the other side). Use this load to complete the design of the adjacent trusses with the column removed.

[0032] The above specific implementations are only for further explanation of the present invention and are not intended to limit the patent of the present invention. Any equivalent implementation of the present invention should be included in the scope of the claims of the patent of the present invention.

Claims

1. A planar design method for a column-removing plant structure considering spatial effects, characterized in that: The method of adding horizontal concentrated forces to the tops of the columns of the removed column frame and the adjacent columns of the removed column frame is adopted to consider the spatial effect of the factory building under the action of wind load. The specific process of the removed column factory building frame design includes the following steps: 1) Design standard frame using plane modeling analysis method; 2) Calculate the column top displacement △1 of the standard frame under wind load; 3) The cross section of the column-removed truss frame is based on the cross section of the standard truss frame. Some columns are removed and only vertical springs are set at the column-removed position to consider the vertical stiffness of the joist. The vertical and horizontal loads are input according to the actual loaded area, and the column top displacement △2 under the action of the wind load is calculated; 4) By inputting the unit concentrated force at the top of the column of the rigid frame, the lateral stiffness K1 of the rigid frame after the column is removed is obtained; 5) Input additional concentrated force at the top of the column frame of the withdrawn column truss in step 4), that is, wind load condition, so that the displacement of the withdrawn column truss frame is consistent with the displacement of the standard truss frame. The additional concentrated force is: F1=(△1-△2)K1; 6) Verify the column-drawing frame and complete the design of the column-drawing frame; 7) The vertical load and horizontal load of the adjacent frame of the withdrawn column are input according to the actual loaded area, and an additional concentrated force F2 is applied to the column top to complete the design of the adjacent frame of the withdrawn column. When the column spacing on both sides of the withdrawn column is equal, take F2=-F1 / 2; when the column spacing on both sides of the withdrawn column is not equal, take F2=[-d1 / (d1 +d2)]F1; among them, d1 is the column spacing between the withdrawn column and the frame on the other side; d2 is the column spacing between the current frame and the withdrawn column frame.

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