A method for designing the width of a wing wall of a special-shaped cross-section steel tube bundle shear wall

Abstract

The application discloses a wing wall width design method of a special-shaped section steel pipe bundle shear wall. The special-shaped section steel pipe bundle shear wall comprises a multi-cavity steel pipe formed by welding a plurality of rectangular steel pipes and concrete poured in the multi-cavity steel pipe. Firstly, the axial compression stability coefficient of a main wall limb when being simply supported on two sides and three sides, the section ultimate bearing capacity of the main wall limb and the section ultimate bearing capacity of a wing wall are determined; according to the above parameters, the amplification coefficient of the wing wall calculation length coefficient is obtained, and then the axial compression stability coefficient of the wing wall around a strong axis is obtained; based on the section ultimate bearing capacity of the wing wall and the axial compression stability coefficient around the strong axis, the critical width-thickness ratio formula that the wing wall needs to meet is determined; finally, the wing wall width is designed according to the critical width-thickness ratio formula. The wing wall width design method of the special-shaped section steel pipe bundle shear wall provided by the application has high theoreticality and accuracy, fills the blank of the prior art and provides guarantee for the structural design of the steel pipe bundle shear wall.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of structural design, and particularly relates to a wing wall width design method of a special-shaped section steel pipe bundle shear wall. TECHNICAL BACKGROUND

[0002] The steel pipe bundle shear wall comprises a multi-cavity steel pipe welded by a plurality of rectangular steel pipes and concrete poured in the multi-cavity steel pipe, and belongs to a steel-concrete composite structure system. In actual engineering, in order to resist lateral loads in different directions, the steel pipe bundle shear wall is usually provided as a special-shaped section, such as T-shaped, L-shaped, etc. For the overall stability problem of the special-shaped section steel pipe bundle shear wall, the special-shaped section wall body is usually divided into a main wall limb (long limb) and a wing wall (short limb), and it is considered that the wing wall can completely limit the out-of-plane displacement of the side edge of the main wall limb, so the main wall limb is regarded as a one-letter-shaped wall body with three-edge support or four-edge support, and finally the stability of the special-shaped section wall body can be evaluated by calculating the stability of the three-edge support / four-edge support main wall limb. However, the accuracy of the above stability calculation method depends on the assumption that the wing wall can completely limit the out-of-plane displacement of the side edge of the main wall limb, so the wing wall of the special-shaped section steel pipe bundle shear wall needs to be provided with sufficient width to ensure the correctness of the above assumption. In summary, it is necessary to establish an accurate wing wall width design method for the special-shaped section steel pipe bundle shear wall.

[0003] At present, there is still a lack of systematic and targeted research on the critical value of the wing wall width of the special-shaped section steel pipe bundle shear wall. The Technical Standard for Steel Pipe Concrete Bundle Structure (T / CECS 546-2018) makes relevant provisions for the wing wall width of the special-shaped section steel pipe bundle shear wall, but the critical width of the wing wall given is a fixed value, and the influence of parameters such as wall height, main wall limb width and wall thickness is not considered. For a wall body with a large height, this provision will make the design dangerous, and for a wall body with a small height, this provision will make the design too conservative, and cannot meet the standardization requirements of the wing wall width of the special-shaped section steel pipe bundle shear wall.

[0004] In view of the above problems, it is necessary to provide a wing wall width design method for the special-shaped section steel pipe bundle shear wall, which can reduce the construction cost and increase the economic benefit at the design level while ensuring the reliability and safety of the structure. SUMMARY

[0005] In order to fill the gap in the existing structural design method and improve the reliability and safety of the steel pipe bundle shear wall, the present application provides a wing wall width design method for the special-shaped section steel pipe bundle shear wall, which solves the problems of lack of wing wall width design method for the special-shaped section steel pipe bundle shear wall in the prior art and inaccurate provisions in related technical regulations. The method provides a clear basis for the geometric parameter standardization design of the wing wall of the special-shaped section steel pipe bundle shear wall, so that the design result has better safety and economy.

[0006] The technical scheme adopted by the present application is:

[0007] A wing wall width design method of a special-shaped section steel pipe bundle shear wall, the special-shaped section steel pipe bundle shear wall comprising a multi-cavity steel pipe welded by a plurality of rectangular steel pipes and concrete poured in the multi-cavity steel pipe;

[0008] The short limb of the special-shaped section steel pipe bundle shear wall is defined as a wing wall, and the long limb of the special-shaped section steel pipe bundle shear wall is defined as a main wall limb;

[0009] The wing wall width design method comprises the following steps:

[0010] Step one: the sectional ultimate bearing capacity N of the wing wall is calculated yf ;

[0011] Step two: the regularized slenderness ratio λ of the wing wall around its strong axis is calculated f , and then the stability coefficient of the wing wall is calculated f by using the regularized slenderness ratio λ

[0012] Step three: the sectional ultimate bearing capacity N yf and the stability coefficient of the wing wall are used to check the stability of the wing wall around its strong axis;

[0013] Step four: the calculation formula of the critical width-thickness ratio of the wing wall is derived according to the stability of the wing wall around its strong axis obtained in step three, the wing wall width design formula is further obtained, and the wing wall width is determined according to the wing wall width design formula.

[0014] In step one, the sectional ultimate bearing capacity N of the wing wall is calculated according to formula (1) yf , specifically including:

[0015]

[0016] α--- the width-thickness ratio of the wing wall,

[0017] d--- the thickness of the wing wall,

[0018] b w --- the width of the main wall limb,

[0019] N yw --- the sectional ultimate bearing capacity of the main wall limb.

[0020] In step two, the regularized slenderness ratio λ of the wing wall around its strong axis is calculated according to formulas (2)-(8) f , specifically including:

[0021] ​

[0022] μ0 —— the calculation length coefficient of the wing wall,

[0023] η —— the amplification coefficient of the calculation length coefficient of the wing wall,

[0024] λ w —— the normalized slenderness ratio of the simply supported main wall around its weak axis under axial compression;

[0025]

[0026] —— the stability coefficient of the simply supported main wall around its weak axis under axial compression,

[0027] —— the stability coefficient of the simply supported main wall around its weak axis under axial compression,

[0028] N f —— the vertical load on the wing wall,

[0029] ΔN —— the vertical bearing capacity of the main wall,

[0030]

[0031]

[0032] λ2 —— the normalized slenderness ratio of the simply supported main wall around its weak axis under axial compression,

[0033] λ3 —— the normalized slenderness ratio of the simply supported main wall around its weak axis under axial compression,

[0034] Φ2 —— the intermediate parameter corresponding to the simply supported main wall,

[0035] Φ3 —— the intermediate parameter corresponding to the simply supported main wall.

[0036] In step two, the stability coefficient of the wing wall is calculated by the normalized slenderness ratio λ f Specifically, it comprises:

[0037]

[0038] —— the stability coefficient of the wing wall around its strong axis under axial compression,

[0039] λ f —— the normalized slenderness ratio of the simply supported wing wall around its strong axis under axial compression,

[0040] Φ —— the intermediate parameter corresponding to the wing wall.​

[0041] In step three, the calculated cross-section ultimate bearing capacity N yf and stability coefficient The stability of the wing wall around its strong axis is checked by formula (11), and formula (12) is obtained, which specifically includes:

[0042]

[0043] N yf The cross-section ultimate bearing capacity of the wing wall.

[0044] In step four, the formula for calculating the critical width-thickness ratio of the wing wall is shown in formula (13):

[0045]

[0046] a - the height of the steel pipe bundle shear wall,

[0047] α0 - the critical width-thickness ratio of the steel pipe bundle shear wall wing wall.

[0048] In step four, the wing wall width design formula is shown in formula (14):

[0049] b f ≥ 0.065a + 0.035b w - 0.051d (14)

[0050] b f The wing wall width of the special-shaped cross-section steel pipe bundle shear wall.

[0051] The above formulas have the following effects:

[0052] 1. Formula (1) is used to calculate the cross-section ultimate bearing capacity of the wing wall;

[0053] 2. Formulas (2)-(8) are used to calculate the regularized slenderness ratio of the simply supported wing wall around its strong axis under axial compression, wherein formula (3) considers the enlargement of the calculation length coefficient, making the calculation result more accurate;

[0054] 3. Formulas (9)-(10) are used to calculate the axial compression stability coefficient of the simply supported wing wall around its strong axis;

[0055] 4. Formulas (11)-(12) are used to check whether the wing wall meets the stability requirements around its strong axis, which are the core formulas of the design method;

[0056] 5. Formula (13) is used to calculate the critical width-thickness ratio of the wing wall, and formula (14) is used to specify the conditions that the wing wall width needs to meet, and formulas (13)-(14) can be directly used for the width design of the special-shaped cross-section steel pipe bundle shear wall, which are the core formulas of the design method.

[0057] The beneficial effects of the present application are embodied in the following two points:

[0058] 1. The conditions that the wing wall width of the special-shaped section steel pipe bundle shear wall must satisfy are determined, which ensures that the wing wall can provide effective support for the side edge of the main wall and ensures the stability of the special-shaped section steel pipe bundle shear wall.

[0059] 2. The wing wall width method of the special-shaped section steel pipe bundle shear wall provided by the present application has higher precision compared to the related provisions in the existing technical regulations, can effectively solve the problems of overly conservative design and excessive safety, and can improve the economy and safety of actual engineering.

[0060] The present application can be widely applied to various buildings with special-shaped section steel pipe bundle shear walls for all or part of the vertical components. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 a is a front view of a special-shaped section steel pipe bundle shear wall (taking a T-shaped section as an example);

[0062] Figure 1 b is a top view of a special-shaped section steel pipe bundle shear wall (taking a T-shaped section as an example);

[0063] Figure 2 a is a buckling mode of a special-shaped section steel pipe bundle shear wall when the wing wall width thickness ratio does not meet the requirements of formula (14);

[0064] Figure 2 b is a buckling mode of a special-shaped section steel pipe bundle shear wall when the wing wall width thickness ratio meets the requirements of formula (14). DETAILED DESCRIPTION

[0065] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0066] A wing wall width design method for a special-shaped section steel pipe bundle shear wall, the special-shaped section steel pipe bundle shear wall comprising a plurality of rectangular steel pipes welded to form a multi-cavity steel pipe and concrete poured into the multi-cavity steel pipe, the short limb of the steel pipe bundle shear wall being defined as a wing wall and the long limb being defined as a main wall limb. The wing wall width design method is carried out according to the following steps:

[0067] 1) Step one

[0068] The wing wall width needs to be greater than the critical value to ensure that when the wing wall provides lateral stiffness to the main wall, it does not occur in-plane overall instability, so it is necessary to calculate whether the wing wall satisfies formula (11):

[0069]

[0070] N f The vertical load acting on the wing wall,

[0071] N yf — the ultimate bearing capacity of the cross section of the wing wall,

[0072] — the stability factor of the wing wall when the overall instability of the wing wall occurs around the strong axis under axial compression.

[0073] 2) Step two

[0074] To check whether the wing wall satisfies formula (11), the ultimate bearing capacity N of the cross section of the wing wall is calculated according to formula (1) yf :

[0075]

[0076] α— the width-thickness ratio of the wing wall,

[0077] d— the thickness of the wing wall,

[0078] b w — the width of the main wall limb,

[0079] N yw — the ultimate bearing capacity of the cross section of the main wall limb.

[0080] 3) Step three

[0081] To check whether the wing wall satisfies formula (11), the stability factor of the wing wall is calculated according to formula (9)-(10)

[0082]

[0083] λ f — the normalized slenderness ratio of the wing wall around the strong axis under axial compression,

[0084] Φ— the corresponding intermediate parameter of the wing wall;

[0085] The normalized slenderness ratio λ of the wing wall around the strong axis under axial compression f is calculated according to formula (2):

[0086]

[0087] μ0— the calculation length coefficient of the wing wall,

[0088] η— the amplification coefficient of the calculation length coefficient of the wing wall,

[0089] λ w — the normalized slenderness ratio of the main wall limb around the weak axis under axial compression;

[0090] The amplification coefficient η of the calculation length coefficient of the wing wall is calculated according to formula (3)-(4):

[0091]

[0092] the stability factor of the main wall pier of two-side simply supported under axial compression around its weak axis,

[0093] the stability factor of the main wall pier of three-side simply supported under axial compression around its weak axis,

[0094] ΔN — the vertical bearing capacity of the main wall pier;

[0095] the stability factor and are calculated according to the formulae (5)-(6) and (7)-(8), respectively:

[0096]

[0097] λ2 — the normalized slenderness ratio of the main wall pier of two-side simply supported under axial compression around its weak axis,

[0098] λ3 — the normalized slenderness ratio of the main wall pier of three-side simply supported under axial compression around its weak axis,

[0099] Φ2 — the intermediate parameter corresponding to the main wall pier of two-side simply supported,

[0100] Φ3 — the intermediate parameter corresponding to the main wall pier of three-side simply supported.

[0101] 4) Step four

[0102] the calculated sectional ultimate bearing capacity N yf and the stability factor are substituted into the formula (11), and the formula (12) for the wing wall is obtained:

[0103]

[0104] 5) Step five

[0105] combined with the formula (12) and the refined numerical simulation results, the calculation formula (13) for the critical width-thickness ratio of the wing wall is derived:

[0106]

[0107] a — the height of the steel pipe bundle shear wall,

[0108] α0 — the critical width-thickness ratio of the wing wall of the steel pipe bundle shear wall;

[0109] According to the formula (13), the design formula (14) for the width of the wing wall is further obtained:

[0110] bf ≥0.065a+0.035b w -0.051d (14)

[0111] b f The wing wall width of the steel pipe bundle shear wall with special-shaped cross section.

[0112] 5) Step six

[0113] Figure 1 a shows the front view of the T-shaped cross section steel pipe bundle shear wall, Figure 1 b shows the top view of the T-shaped cross section steel pipe bundle shear wall, and each geometric parameter is labeled Figure 1 .

[0114] According to the geometric parameters of the steel pipe bundle shear wall with special-shaped cross section, the width-thickness ratio (b w / d) and the height-thickness ratio (a / d) of the main wall limb are determined, the critical width-thickness ratio of the wing wall under different height-thickness ratios and width-thickness ratios is calculated by using the calculation formula (13) of the critical width-thickness ratio of the wing wall, and the related data are summarized in Table 1:

[0115] Table 1 Critical width-thickness ratio of wing wall

[0116]

[0117] According to the calculated critical width-thickness ratio of the wing wall, the critical width can also be determined by referring to Table 1. Finally, the width of the wing wall is designed according to formula (15):

[0118] b f ≥α0·d (15)

[0119] If the width of the main wall limb b w = 3000 mm, the height of the wall a = 6400 mm, and the thickness of the wall d = 100 mm, a / d = 64 and b w / d = 30 can be calculated, according to formula (13) or Table 1, the critical width-thickness ratio of the wing wall is 5.159, which should be taken as 6, according to formula (15), the calculated width of the wing wall can be taken as 600 mm.

[0120] And the Technical Standard for Steel Pipe Concrete Bundle Structure (T / CECS 546-2018) also makes relevant provisions for the wing wall width of the steel pipe bundle shear wall with special-shaped cross section, and the second paragraph of section 6.3.1 stipulates that the width-thickness ratio of the wing wall should not be less than 4. Therefore, according to the Technical Standard for Steel Pipe Concrete Bundle Structure, the wing wall width in this example can be taken as 400 mm, which is less than the value calculated by the method described in the present application.

[0121] The accuracy of the method and the relevant provisions of the Technical Standard for Steel Tube Concrete Beam Structure is verified by numerical simulation, and the results are compared. First, two finite element models of special-shaped cross-section steel tube beam shear walls are established. The wing wall width of model 1 is 400 mm, and the wing wall width of model 2 is 600 mm, and the rest of the geometric parameters are according to the values taken in this example. Figure 2 a shows the buckling mode of the special-shaped cross-section steel tube beam shear wall when the wing wall width is 400 mm. It can be found that the wall body occurs overall instability around the weak axis, and at this time, the wing wall cannot be used as the out-of-plane supporting edge of the main wall limb; Figure 2 b shows the buckling mode of the special-shaped cross-section steel tube beam shear wall when the wing wall width is 600 mm. It can be found that the main wall limb occurs out-of-plane instability around the weak axis, and the wing wall does not appear instability around the overall weak axis. The edge of the intersection of the main wall limb and the wing wall does not appear out-of-plane deformation, so the wing wall can be used as the out-of-plane supporting edge of the main wall limb.

[0122] In summary, the wing wall width design method described in the application is accurate and reliable, and the relevant provisions in the Technical Standard for Steel Tube Concrete Beam Structure are dangerous in some cases, so the application has good engineering application value.

Claims

1. A method for designing the wing wall width of an irregularly shaped cross-section steel tube bundle shear wall, characterized in that, The irregular cross-section steel tube bundle shear wall includes a multi-cavity steel tube welded from multiple rectangular steel tubes and concrete poured inside the multi-cavity steel tube; The short limb of the irregular cross-section steel tube bundle shear wall is defined as the wing wall, and the long limb of the irregular cross-section steel tube bundle shear wall is defined as the main wall limb. The wing wall width design method includes the following steps: Step 1: Calculate the ultimate bearing capacity N of the wing wall section. yf ; Step 2: Calculate the regularized slenderness ratio λ of the simply supported wing walls on both sides about their own strong axis under axial compression. f Then, by regularizing the slenderness ratio λ f The stability coefficient of the wing wall was calculated. Step 3: Use the calculated ultimate bearing capacity N of the section yf and stability coefficient Verify the stability of the wing wall about its own strong axis; Step 4: Based on the stability of the wing wall around its own strong axis obtained in Step 3, the calculation formula for the critical width-to-thickness ratio of the wing wall is derived, and the design formula for the wing wall width is further obtained. The wing wall width is determined according to the wing wall width design formula. In step four, the design formula for the wing wall width is shown in equation (14): b f ≥0.065a+0.035b w -0.051d (14) b f —The width of the wing wall of an irregularly shaped cross-section steel tube bundle shear wall. a — Height of the steel tube shear wall b w —Width of the main wall segment, d — thickness of the wing wall.

2. The method for designing the wing wall width of an irregularly shaped cross-section steel tube bundle shear wall according to claim 1, characterized in that, In step one, the ultimate bearing capacity N of the wing wall section is calculated according to equation (1). yf Specifically, it includes: α — Width-to-thickness ratio of the wing wall. d—thickness of the wing wall b w —Width of the main wall segment, N yw —The ultimate bearing capacity of the main wall segment.

3. The method for designing the wing wall width of an irregularly shaped cross-section steel tube bundle shear wall according to claim 2, characterized in that, In step two, the regularized slenderness ratio λ of the simply supported wing walls on both sides about their own strong axis under axial compression is calculated according to equations (2)-(8). f Specifically, it includes: μ0 — Calculation length coefficient of the wing wall. η—Magnification factor for the calculated length coefficient of the wing wall. λ2——The regularized slenderness ratio of the simply supported main wall segments on both sides about their weak axis under axial compression; —Stability coefficient when the two simply supported main wall segments experience overall instability under axial compression around their weak axes. —Stability coefficient when a three-sided simply supported main wall experiences overall instability under axial compression around its weak axis. N f —Vertical loads on the wing walls, ΔN—Vertical bearing capacity of the main wall segment during lifting; λ3 — The regularized slenderness ratio of a simply supported three-sided main wall segment about its weak axis under axial compression. Φ2—Intermediate parameter corresponding to the main wall segments with simple support on both sides. Φ3——Intermediate parameter corresponding to the main wall segment with three sides simply supported.

4. The method for designing the wing wall width of an irregularly shaped cross-section steel tube bundle shear wall according to claim 3, characterized in that, In step two, equations (9)-(10) are used to regularize the slenderness ratio λ. f The stability coefficient of the wing wall was calculated. Specifically, it includes: —Stability coefficient when the wing wall experiences overall instability under axial compression around its own strong axis. λ f —The regularized slenderness ratio of the simply supported wing walls about their own strong axis under axial compression. Φ — Intermediate parameters corresponding to the wing wall.

5. The method for designing the wing wall width of an irregularly shaped cross-section steel tube bundle shear wall according to claim 4, characterized in that, In step three, the calculated ultimate bearing capacity N of the cross section is used. yf and stability coefficient By verifying the stability of the wing wall about its own strong axis using formula (11), we obtain formula (12), which specifically includes: N yf —The ultimate bearing capacity of the wing wall section.

6. The method for designing the wing wall width of an irregularly shaped cross-section steel tube bundle shear wall according to claim 5, characterized in that, In step four, the formula for calculating the critical width-to-thickness ratio of the wing wall is shown in equation (13): a — Height of the steel tube shear wall α0 — Critical width-to-thickness ratio of the wing wall of the steel tube shear wall.

Images