A method for determining the ultimate bearing capacity of a hot-rolled double- limb channel spliced column under axial compression

Abstract

The present application belongs to the field of civil engineering, and relates to a method for determining the ultimate bearing capacity of a hot-rolled double-limb channel steel spliced column under axial compression, comprising the following steps: determining the bolt spacing to calculate the equivalent bolt spacing according to the designed double-limb hot-rolled channel steel spliced column; determining the axial compression correction coefficient according to the calculation length of the spliced column and the equivalent bolt spacing; determining the bolt adjustment coefficient according to the arranged bolt grade, specification and column number, and then determining the bolt strengthening coefficient; and finally determining the ultimate bearing capacity of the double-limb hot-rolled channel steel spliced column under axial compression. The present application provides a method for determining the ultimate bearing capacity of a double-limb hot-rolled channel steel spliced column under axial compression, which is suitable for checking the ultimate bearing capacity of the spliced column of the existing assembly type modular container house.

Description

Technical Field

[0001] This invention patent belongs to the field of civil engineering and relates to a method for determining the ultimate bearing capacity of a hot-rolled channel steel spliced ​​column under axial compression with two limbs. Background Technology

[0002] Steel components are widely used in industrial and civil buildings. While meeting the growing needs of people's production and daily life, their structural forms and stress conditions are becoming increasingly complex. Traditional single components, although clear in their stress distribution and convenient in design, are insufficient to meet the multi-functional requirements of actual engineering projects. Composite components have emerged due to their flexible and diverse combination methods. Composite components are cross-sectional members assembled from two or more single components using bolts, studs, and welding. Compared to single components, the load-bearing capacity is improved after assembly, driving the development of steel structures towards multi-functionality. (Patent) CN111535504A discloses a design method for hot-rolled channel steel splicing beams with unequal height sections. By determining the value of the bolt spacing, the ultimate bearing capacity of the splicing beam can be effectively improved. While ensuring structural safety, the material strength can be maximized, resulting in good economic efficiency. Patent CN210828062U discloses a splicing steel member with double-limb back-to-back C-shaped steel web openings and stiffening ribs. This solves the problem of low free torsional stiffness of single-limb cold-formed thin-walled members, meets the requirements of structural stress and opening for wiring, and has good application prospects.

[0003] Double-limb hot-rolled channel steel composite columns, as a typical representative of prefabricated modular container houses, are mainly suitable for their frame columns. These containers typically use perforated channel steel; the splicing of multiple perforated channel steels allows for the lateral combination of containers. The channel steels are fixed together with bolts, reducing on-site welding procedures and making construction convenient and quick. This invention patent proposes a method for determining the ultimate bearing capacity of double-limb hot-rolled channel steel composite columns under axial pressure, applicable to the ultimate bearing capacity verification of composite columns in existing prefabricated modular container houses. Summary of the Invention

[0004] The purpose of this invention is to provide a method for determining the ultimate bearing capacity of a hot-rolled channel steel splice column under axial compression with two limbs.

[0005] This invention is achieved through the following technical solution:

[0006] A method for determining the ultimate bearing capacity of an axially compressed double-limb hot-rolled channel steel composite column, characterized in that the double-limb hot-rolled channel steel composite column is composed of two single-limb hot-rolled channel steels and multiple high-strength bolts. The web of each single-limb hot-rolled channel steel has multiple bolt holes, and the back-to-back splicing between the webs of the two single-limb channel steels is achieved by the multiple high-strength bolts. The determination method includes the following steps:

[0007] The first step is to determine the bolt spacing based on the designed double-limb hot-rolled channel steel splice column, including the axial bolt spacing S in the middle area and the bolt spacing S1 in the end area, which must satisfy 1.0≤S / S1<1.3;

[0008] The second step is to determine the equivalent bolt spacing S based on the boundary conditions of the double-limb hot-rolled channel steel composite column and the various bolt spacings. e ;

[0009]

[0010] In the formula: μ—calculation length coefficient; S i —Axial spacing (mm) between the i-th group of bolts and the (i+1)-th group of bolts on the splicing column; L —Length of the splicing column (mm); S —Axial spacing (mm) of bolts in the middle area of ​​the splicing column;

[0011] The third step is to calculate the length μL of the double-limb hot-rolled channel steel spliced ​​column and the equivalent bolt spacing S. e Determine the correction factor for axial compression of the double-limb hot-rolled channel steel spliced ​​column;

[0012]

[0013] Where: μ—calculated length coefficient; L—length of the assembled column (mm); S e — Equivalent axial spacing of bolts (mm);

[0014] The fourth step is to determine the bolt adjustment coefficient c according to Table 1 based on the bolt grade, specifications, and number of rows n of the designed double-limb hot-rolled channel steel spliced ​​column. Table 1 Bolt Adjustment Coefficient c Note: The applicable range for the cross-sectional height of hot-rolled channel steel in the table is 140mm≤h≤320mm.

[0015] Fifth step: Determine the bolt reinforcement coefficient ψ based on the bolt adjustment coefficient c;

[0016] Where: h—height of hot-rolled channel steel section (mm); c—bolt adjustment coefficient, adopted according to Table 1;

[0017] Step 6: Based on the calculation results of the above steps, determine the ultimate bearing capacity of the axially compressed double-limb hot-rolled channel steel composite column:

[0018]

[0019] Where: K acr—Axial compression correction coefficient for double-limb hot-rolled channel steel spliced ​​columns, see formula (2); EI —Bending stiffness of spliced ​​columns (N·mm) 2 ); ψ—bolt reinforcement coefficient, see formula (3); L—length of the spliced ​​column (mm); S1—axial spacing of bolts in the end area of ​​the spliced ​​column (mm); S—axial spacing of bolts in the middle area of ​​the spliced ​​column (mm); S e — Equivalent axial spacing of bolts (mm);

[0020] The beneficial effects of this invention patent are as follows: For existing double-limb hot-rolled channel steel composite columns, the axial compression correction coefficient can be determined by the equivalent bolt arrangement spacing, and various bolt coefficients can be determined according to the bolt arrangement, thereby determining the ultimate bearing capacity of the axially compressed double-limb hot-rolled channel steel composite column. The determination method proposed in this invention is applicable to the ultimate bearing capacity verification of the composite columns of existing prefabricated modular container houses. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the method for determining the ultimate bearing capacity of a double-limb hot-rolled channel steel spliced ​​column under axial compression in an embodiment of the present invention.

[0022] Figure 2 This is a cross-sectional layout diagram of the double-limb hot-rolled channel steel spliced ​​column in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of the double-limb hot-rolled channel steel spliced ​​column in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the parameters of the double-limb hot-rolled channel steel spliced ​​column in the embodiment of the present invention.

[0025] In the diagram: 1. Single-limb hot-rolled channel steel; 2. High-strength bolt. Detailed Implementation

[0026] The present technology will be further described below with reference to the accompanying drawings and embodiments.

[0027] Example

[0028] A 3.6m long, axially compressed, double-limb hot-rolled channel steel composite column with a hinged upper end and a fixed lower end consists of hot-rolled channel steel 1 and high-strength bolts 2. The hot-rolled channel steel 1 has a cross-section of [18a (180×68×7×10.5)]. Two rows of 10.9 grade M22 high-strength bolts are arranged on the web of the hot-rolled channel steel. The axial spacing of the bolts in the middle area and the end area is 400mm and 350mm, respectively.

[0029] The first step is to set the axial spacing S of the bolts in the middle zone to be 400 mm and the axial spacing S1 of the bolts in the end zone to be 350 mm, and satisfy 1.0 ≤ S / S1 < 1.3.

[0030] The second step is to determine the equivalent bolt spacing S based on the boundary conditions of the double-limb hot-rolled channel steel composite column and the various bolt spacings. e ;

[0031]

[0032] In the formula: μ—calculation length coefficient; S i —Axial spacing (mm) between the i-th group of bolts and the (i+1)-th group of bolts on the splicing column; L —Length of the splicing column (mm); S —Axial spacing (mm) of bolts in the middle area of ​​the splicing column;

[0033] The third step is to calculate the length μL of the double-limb hot-rolled channel steel spliced ​​column and the equivalent bolt spacing S. e Determine the correction factor for axial compression of the double-limb hot-rolled channel steel spliced ​​column;

[0034]

[0035] Where: μ—calculated length coefficient; L—length of the assembled column (mm); S e — Equivalent axial spacing of bolts (mm);

[0036] The fourth step is to use a bolt adjustment coefficient of c = 0.957 according to Table 1, based on the bolt grade, specifications and number of rows n of the designed double-limb hot-rolled channel steel spliced ​​column.

[0037] Fifth step: Determine the bolt reinforcement coefficient ψ based on the bolt adjustment coefficient c;

[0038]

[0039] Where: h—height of hot-rolled channel steel section (mm); c—bolt adjustment coefficient, adopted according to Table 1;

[0040] Step 6: Based on the calculation results of the above steps, determine the ultimate bearing capacity of the axially compressed double-limb hot-rolled channel steel composite column:

[0041]

[0042] Where: K acr —Axial compression correction coefficient for double-limb hot-rolled channel steel spliced ​​columns, see formula (2); EI —Bending stiffness of spliced ​​columns (N·mm) 2 ); ψ—bolt reinforcement coefficient, see formula (3); L—length of the spliced ​​column (mm); S1—axial spacing of bolts in the end area of ​​the spliced ​​column (mm); S—axial spacing of bolts in the middle area of ​​the spliced ​​column (mm); S e — Equivalent axial spacing of bolts (mm);

[0043] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for determining the ultimate bearing capacity of an axially compressed double-limb hot-rolled channel steel composite column, characterized in that, The double-limb hot-rolled channel steel splicing column is composed of two single-limb hot-rolled channel steels and a series of high-strength bolts. The web of each single-limb hot-rolled channel steel has a series of bolt holes. The back-to-back splicing between the webs of the two single-limb channel steels is achieved by means of the series of high-strength bolts. The determination method includes the following steps: The first step is to determine the bolt spacing based on the designed double-limb hot-rolled channel steel splice column, including the axial bolt spacing S in the middle area and the bolt spacing S1 in the end area, which must satisfy 1.0≤S / S1<1.3; The second step is to determine the equivalent bolt spacing S based on the boundary conditions of the double-limb hot-rolled channel steel composite column and the various bolt spacings. e ; In the formula: μ — calculation length coefficient; S i — The axial spacing (mm) between the i-th group of bolts and the (i+1)-th group of bolts arranged on the splicing column; L—Length of the assembled column (mm); S—Axial spacing of bolts in the middle area of ​​the assembled column (mm); The third step is to calculate the length μL of the double-limb hot-rolled channel steel spliced ​​column and the equivalent bolt spacing S. e Determine the correction factor for axial compression of the double-limb hot-rolled channel steel spliced ​​column; In the formula: μ — calculation length coefficient; L—Length of the assembled column (mm); S e — Equivalent axial spacing of bolts (mm); The fourth step is to determine the bolt adjustment coefficient c according to Table 1 based on the bolt grade, specifications, and number of rows n of the designed double-limb hot-rolled channel steel spliced ​​column. Table 1 Bolt Adjustment Coefficient c Note: The applicable range for the cross-sectional height of hot-rolled channel steel in the table is 140mm≤h≤320mm; Fifth step: Determine the bolt reinforcement coefficient ψ based on the bolt adjustment coefficient c; Where: h——height of hot-rolled channel steel section (mm); c—bolt adjustment coefficient, adopted according to Table 1; Step 6: Based on the calculation results of the above steps, determine the ultimate bearing capacity of the axially compressed double-limb hot-rolled channel steel composite column: Where: K acr —Correction coefficient for axial compression of double-limb hot-rolled channel steel spliced ​​column, see formula (2); EI – Bending stiffness of the composite column (N·mm) 2 ); ψ—— Bolt reinforcement coefficient, see formula (3); L—Length of the assembled column (mm); S1—Axial spacing of bolts in the spliced ​​column end area (mm); S—Axial spacing of bolts in the middle area of ​​the assembled column (mm); S e — Equivalent axial spacing of bolts (mm).

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