Characteristic cycle analysis method for seismic design of engineering structure

Abstract

The invention discloses a characteristic cycle analysis method for seismic design of an engineering structure in the field of seismic design of the engineering structure, which comprises the following steps of: investigating a target work point, and determining a design seismic group of the target work point, a site category boundary region of the target work point and a category of the site category boundary region; the site category boundary area is an area within + / -15% of the site category boundary; selecting an applicable characteristic period interpolation formula for the determined site category boundary region; and determining parameter values in the interpolation formula on the basis of the design seismic group of the target work point and the category of the site category boundary region where the target work point is located, and substituting the parameter values to calculate the characteristic period of the target work point. According to the method, the calculation precision of the characteristic period is improved, the calculation accuracy and safety of the seismic action of the engineering structure are ensured, and a scientific and standard basis is provided for the seismic design of the engineering structure.

Description

Technical Field

[0001] The invention relates to a characteristic period analysis method for earthquake-resistant design of engineering structures, and belongs to the field of earthquake-resistant design of engineering structures. Background Art

[0002] At present, the elastic response spectrum theory is still the most basic theory for the seismic design of engineering structures at this stage. The characteristic period is one of the most important parameters in the response spectrum theory calculation. The accuracy of its value directly affects the accuracy of the calculation of the seismic action of the engineering structure. "General Code for Seismic Design of Buildings and Municipal Engineering" (GB55002-2021), as a mandatory provision for engineering construction, was officially implemented on January 1, 2022. Article 4.2.2 of the code clearly states that when there are reliable shear wave velocities and cover layer thicknesses and their values ​​are within the range of ±15% of the boundary line of the site categories listed in Table 3.1.3 of this code, the characteristic period should be determined by the interpolation method. However, the code does not give a specific description of the interpolation method. The text of Article 4.1.6 of the "Code for Seismic Design of Buildings (2016 Edition)" (GB50011-2010) gives the design earthquake grouping as the first group. The specific process and interpolation formula of characteristic period interpolation are not given. The characteristic period is roughly estimated by drawing a straight line on the plane diagram. The inaccuracy of drawing the straight line on the diagram and the accumulated errors of human judgment are likely to lead to large errors in the value of the characteristic period, which directly affects the accuracy of the calculation of the seismic action of the engineering structure. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a characteristic period analysis method for seismic design of engineering structures, thereby improving the accuracy of characteristic period calculation in the site boundary area by clarifying specific characteristic period interpolation formulas, and ensuring the accuracy and safety of seismic action calculations on engineering structures.

[0004] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0005] The present invention provides a characteristic period analysis method for seismic design of engineering structures, comprising:

[0006] Conduct an investigation on the target construction site to determine the design earthquake grouping of the target construction site, the site category boundary area where the target construction site is located, and the category of the site category boundary area, wherein the site category boundary area is the area within ±15% of the site category boundary;

[0007] For the determined site category boundary area, select the applicable characteristic period interpolation formula;

[0008] Based on the design earthquake grouping of the target construction site and the category of the site category boundary area where the target construction site is located, the parameter values ​​in the interpolation formula are determined and substituted into the calculation of the characteristic period of the target construction site.

[0009] Further, determining the design earthquake group of the target construction site and the site category boundary area where the target construction site is located includes:

[0010] Determine the design earthquake grouping of the target construction point based on the seismic activity level and seismic motion parameters of the area where the target construction point is located; and site cover thickness , determine the target working point at Coordinates of the boundary line and its ±15% range in the plane ( , ), and accordingly determine the site category boundary area where the target work point is located;

[0011] The design earthquake groups are divided into a first group, a second group and a third group;

[0012] The site categories are divided into Class I1, Class II, Class III and Class IV;

[0013] The site category boundary area is divided into a boundary area between Class I1 and Class II sites, a boundary area between Class II and Class III sites, and a boundary area between Class III and Class IV sites.

[0014] Furthermore, the area within the range of ±15% of the site category boundary includes:

[0015] The first vertical area is surrounded by points A, B, C, and D; the first horizontal area is surrounded by points C, D, E, and F; the second vertical area is surrounded by points E, F, G, and H; the second horizontal area is surrounded by points G, H, J, and K;

[0016] The site category boundary line in the first vertical area, the boundary line formed by ±15% of the site category boundary line and The horizontal axis of the plane dividing line and its ±15% range The intersecting horizontal coordinates are , , ; The site category boundary line within the first horizontal area, the boundary line formed by ±15% of the site category boundary line and The vertical axis of the plane dividing line and its ±15% range The intersecting ordinates are , , ; The site category boundary line in the second vertical area, the boundary line formed by ±15% of the site category boundary line and The horizontal axis of the plane dividing line and its ±15% range The intersecting horizontal coordinates are , , ; The site category boundary line in the second horizontal area, the boundary line formed by ±15% of the site category boundary line and The vertical axis of the plane dividing line and its ±15% range The intersecting ordinates are , , ; The common edge between the first vertical area and the first horizontal area is L1, the common edge between the first horizontal area and the second vertical area is L2, and the common edge between the second vertical area and the second horizontal area is L3; the site category dividing line separates the site areas of different categories, the area category above the dividing line is set to k, where k is Class I1, Class II or Class III, and the area category below the dividing line is set to k+1, where k+1 is Class II, Class III or Class IV; L1~L3 are three finite spatial straight lines, defined in the coordinate system ( , , ), among which is the characteristic period; as the thickness of the site cover The decrease of soil equivalent shear wave velocity The characteristic cycle is increasing. It shows a linear decreasing trend; L1~L3 have upper and lower endpoints respectively; the characteristic period of the lower and upper endpoints of L1~L3 from Linearly decreases to , the reduction is , represents the characteristic period of the lower endpoint of site category k+1, Indicates the characteristic period of the upper endpoint of site category k, the same characteristic period The points on the line are connected to form a Contour lines;

[0017] in, , , , As shown below:

[0018] .

[0019] Furthermore, the characteristic period general interpolation formula is solved by interpolating the point-wise equations of the spatial lines L1 and L3. The point-wise equations of L1, L2 and L3 are related to the thickness of the site cover layer. , soil equivalent shear wave velocity , characteristic period The three-dimensional variable equation ( , , );

[0020] L1 is a straight line defined by the lower endpoint C and the upper endpoint D. The coordinates of point C and point D are: C (1.15 , 0.85 , )、D(0.85 , 1.15 , ), L1 direction vector =(0.3 , -0.3 , ), L1 is represented by the point D, and the direction vector is The space straight line, ( , , ) represents the coordinates of a point on L1, then the point-wise equation of L1 is:

[0021] ; (1)

[0022] L3 is a straight line defined by the lower endpoint G and the upper endpoint H. The coordinates of point G and point H are: G (1.15 , 0.85 , )、H(0.85 , 1.15 , ), L3 direction vector =(0.3 , -0.3 , ), L3 is represented by the point H, and the direction vector is The space straight line, ( , , ) represents the coordinates of a point on L3, then the point-wise equation of L3 is:

[0023] ; (2)

[0024] For the determined site category boundary area, select the applicable characteristic period general interpolation formula, including:

[0025] When the target working point ( , ) is located in the first vertical region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is:

[0026] ; (3)

[0027] When the target working point ( , ) is within the first horizontal region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is:

[0028] ; (4)

[0029] When the target working point ( , ) is located in the first vertical region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is:

[0030] ; (5)

[0031] When the target working point ( , ) is within the second horizontal area, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is:

[0032] ; (6)

[0033] Combining the above formulas (3) to (6), the characteristic period of the site boundary area is obtained: The general interpolation formula is:

[0034] .

[0035] Further, based on the design earthquake grouping of the target construction point and the category of the site category boundary area where the target construction point is located, the parameter values ​​in the interpolation formula are determined, including:

[0036] When the design earthquake group is the first, second or third group, and the target construction site is located in the boundary area between the I1 and II sites, set the parameters k=I1, k+1=II, and determine the parameter values ​​in the interpolation formula in combination with the reference values ​​provided in the General Code for Seismic Resistance of Buildings and Municipal Engineering GB55002-2021;

[0037] When the target work site is located in the boundary area between Class II and Class III sites, set the parameters k=II, k+1=III, and determine the parameter values ​​in the interpolation formula in combination with the reference values ​​in the specification;

[0038] When the target work site is located in the boundary area between Class III and Class IV sites, set the parameters k=III, k+1=IV, and determine the parameter values ​​in the interpolation formula in combination with the reference values ​​in the specification;

[0039] The parameters include: , , , , , , ;

[0040] When the design earthquake grouping changes, the parameters in the interpolation formula , , ,and Keep the parameters unchanged. , and It will be adjusted according to different design earthquake groups in combination with the "General Code for Seismic Resistance of Buildings and Municipal Engineering" GB55002-2021.

[0041] Furthermore, when the design earthquake group is in the first group and the target construction site is located in the boundary area between Class I1 and Class II sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​provided in the General Code for Seismic Resistance of Buildings and Municipal Engineering GB55002-2021, including:

[0042] , , = 0.1s, =3m, =5m, =250m / s, =500m / s;

[0043] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories I1 and II when the design earthquake group is in the first group. The interpolation formula is as follows:

[0044] ; (7)

[0045] When the target construction site is located in the boundary area between Class II and Class III sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including:

[0046] = 0.35s, =0.45s, = 0.1s, =15m, =50m, =150m / s, =250m / s;

[0047] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories II and III when the design earthquake group is in the first group. The interpolation formula is as follows:

[0048] ; (8)

[0049] When the target construction site is located in the boundary area between Class III and Class IV sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including:

[0050] =0.45s, =0.65s, = 0.2s, =80m, =150m / s;

[0051] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories III and IV when the design earthquake group is in the first group. The interpolation formula is as follows:

[0052] ; (9)

[0053] Combining the above formulas (7) to (9), it is concluded that when the design earthquake group is in the first group, the characteristic period of the boundary area of ​​different site categories is The general interpolation formula is as follows:

[0054] .

[0055] Furthermore, when the design earthquake group is in the second group and the target construction site is located in the boundary area between Class I1 and Class II sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​provided in the General Code for Seismic Resistance of Buildings and Municipal Engineering GB55002-2021, including:

[0056] = 0.30s, = 0.40s, =0.1s;

[0057] When the target construction site is located in the boundary area between Class II and Class III sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including:

[0058] = 0.40s, =0.55s, 0.15s;

[0059] When the target construction site is located in the boundary area between Class III and Class IV sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including:

[0060] =0.55s, = 0.75s, 0.2s;

[0061] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to derive the characteristic period of the boundary area of ​​different site categories when the design earthquake group is in the second group. The general interpolation formula is as follows:

[0062] .

[0063] Furthermore, when the design earthquake group is in the third group and the target construction site is located in the boundary area between Class I1 and Class II sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​provided in the General Code for Seismic Resistance of Buildings and Municipal Engineering GB55002-2021, including:

[0064] = 0.35s, =0.45s, =0.1s;

[0065] When the target construction site is located in the boundary area between Class II and Class III sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including:

[0066] =0.45s, =0.65s, 0.2s;

[0067] When the target construction site is located in the boundary area between Class III and Class IV sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including:

[0068] =0.65s, =0.9s, 0.25s;

[0069] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to derive the characteristic period of the boundary area of ​​different site categories when the design earthquake group is in the third group. The general interpolation formula is as follows:

[0070] .

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] The present invention provides a characteristic period analysis method for seismic design of engineering structures, which effectively solves the problem that the prior art specifications lack specific descriptions of characteristic period interpolation methods. The present invention accurately selects applicable characteristic period interpolation formulas according to the requirements of the specifications through the design earthquake grouping of the target work site and the site category boundary area, and determines the calculation results through specific parameters, thereby avoiding the characteristic period value deviation caused by errors in plane drawing and manual judgment in the prior art. Such a method improves the accuracy of characteristic period calculation, ensures the accuracy and safety of calculation of seismic effects on engineering structures, and provides a scientific and standardized basis for seismic design of engineering structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 The first embodiment of the present invention provides The dividing line and its ±15% range on the plane;

[0074] Figure 2 This is the site boundary area interpolation zoning map provided in the first embodiment of the present invention. DETAILED DESCRIPTION

[0075] 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 application and the specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0076] The terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this disclosure / application, unless otherwise specified, "plurality" means two or more.

[0077] Embodiment 1:

[0078] This embodiment provides a characteristic period analysis method for seismic design of engineering structures, including:

[0079] Conduct an investigation on the target construction site to determine the design earthquake grouping of the target construction site, the site category boundary area where the target construction site is located, and the category of the site category boundary area, wherein the site category boundary area is the area within ±15% of the site category boundary;

[0080] For the determined site category boundary area, select an applicable characteristic period interpolation formula; based on the design earthquake grouping of the target work point and the category of the site category boundary area where the target work point is located, determine the parameter values ​​in the interpolation formula and substitute them into the calculation of the characteristic period of the target work point.

[0081] In my country, the relevant specifications and requirements for design earthquake grouping are mainly provided by the Code for Seismic Design of Buildings (GB50011-2010), and further detailed in its 2016 revised edition. In addition, the General Code for Seismic Design of Buildings and Municipal Engineering (GB55002-2021) also provides detailed requirements for design earthquake grouping. Design earthquake grouping is usually divided into three groups to reflect the earthquake risk levels and requirements in different regions:

[0082] Group 1: areas with low seismicity and the lowest seismic design standards;

[0083] Group 2: moderate seismic activity areas, with moderate design requirements;

[0084] Group 3: Areas with high seismic activity have the highest seismic design requirements.

[0085] Article 4.1.6 of the Code for Seismic Design of Buildings (2016 Edition) (GB50011-2010) states that the site category of a building should be divided into four categories according to the equivalent shear wave velocity of the soil layer and the thickness of the site cover layer according to Table 4.1.6, of which Category I is divided into two subcategories, I0 and I1. Since Category I0 does not involve the boundary line of the site category within the range of ±15%, this embodiment only considers Category I1 in Category I and the other three categories, Category II, Category III and Category IV.

[0086] Furthermore, the design earthquake grouping of the target construction site is determined based on the seismic activity level and seismic motion parameters of the area where the target construction site is located; and the equivalent shear wave velocity of the soil layer at the target construction site is determined based on the equivalent shear wave velocity of the soil layer at the target construction site. and site cover thickness , determine the target working point at Coordinates of the boundary line and its ±15% range in the plane ( , ).

[0087] like Figure 2 As shown, the areas within ±15% of the site category boundary include:

[0088] The first vertical area is surrounded by points A, B, C, and D; the first horizontal area is surrounded by points C, D, E, and F; the second vertical area is surrounded by points E, F, G, and H; the second horizontal area is surrounded by points G, H, J, and K;

[0089] Among them, the site category boundary line in the first vertical area, the boundary line formed by ±15% of the site category boundary line and the thickness of the site cover layer on the horizontal axis of the China Earthquake Motion Parameter Zoning Map The intersecting horizontal coordinates are , , ; The site category boundary line in the first horizontal area, the boundary line formed by ±15% of the site category boundary line and the longitudinal shear wave velocity The intersecting ordinates are , , ; The site category boundary line in the second vertical area, the boundary line formed by ±15% of the site category boundary line and the thickness of the horizontal axis site cover layer The intersecting horizontal coordinates are , , ; The site category boundary line in the second horizontal area, the boundary line formed by ±15% of the site category boundary line and the longitudinal shear wave velocity The intersecting ordinates are , , ; The common edge between the first vertical area and the first horizontal area is L1, the common edge between the first horizontal area and the second vertical area is L2, and the common edge between the second vertical area and the second horizontal area is L3; the site category dividing line separates the site areas of different categories. The area category above the dividing line is set to k, k=(I1, II, III), and the area category below is k+1, k+1=(II, III, IV); L1~L3 are three finite spatial lines, defined in the coordinate system ( , , ), among which is the characteristic period; as the thickness of the site cover The decrease of soil equivalent shear wave velocity The characteristic cycle is increasing. It shows a linear decreasing trend; L1~L3 have upper and lower endpoints respectively; the characteristic period of the lower and upper endpoints of L1~L3 from Linearly decreases to , the reduction is , represents the characteristic period of the lower endpoint of site category k+1, Indicates the characteristic period of the upper endpoint of site category k, the same characteristic period The line formed by connecting the points on Contour lines;

[0090] in, , , , As shown in the formula:

[0091] ;

[0092] The characteristic period general interpolation formula is solved by interpolating the point-wise equations of the spatial lines L1 and L3. The point-wise equations of L1, L2 and L3 are related to the thickness of the soil cover layer on the site. , soil equivalent shear wave velocity , characteristic period The three-dimensional variable equation ( , , );

[0093] According to the description of Article 4.1.6 of the Code for Seismic Design of Buildings (2016 Edition) (GB50011-2010), on the site category boundary area map, the characteristic period is allowed to be determined by the interpolation method within the area of ​​±15% of the site boundary. The present invention uses a continuous linear interpolation method to solve the characteristic period within the area of ​​±15% of the site boundary. The coordinate points on the boundary line between site k and k+1 can be determined according to the specification. By determining any point on the spatial straight line and the direction vector parallel to the spatial straight line, the point-to-point equations of the spatial straight lines L1 and L3 can be determined based on the knowledge of higher mathematics. The site boundary can be obtained based on ±15% of the boundary line. Through the linear change of the characteristic period on the boundary lines L1 and L3, it is known that , In the case of , the characteristic period of any target working point is obtained by interpolation. Since the characteristic period changes continuously and linearly within the region, the characteristic period in the geological survey report can be directly used. , Calculating the characteristic period in the target area is a method to quickly calculate the characteristic period.

[0094] like Figure 2 As shown, L1 is the straight line determined by the lower end point C and the upper end point D. The coordinates of point C and point D are: C (1.15 , 0.85 , )、D(0.85 , 1.15 , ), L1 direction vector =(0.3 , -0.3 , ), L1 is represented by the point D, and the direction vector is The space straight line, ( , , ) represents the coordinates of a point on L1, then the point-wise equation of L1 is:

[0095] ; (1)

[0096] L3 is a straight line defined by the lower endpoint G and the upper endpoint H. The coordinates of point G and point H are: G (1.15 , 0.85 , )、H(0.85 , 1.15 , ), L3 direction vector =(0.3 , -0.3 , ), L3 is represented by the point H, and the direction vector is The space straight line, ( , , ) represents the coordinates of a point on L3, then the point-wise equation of L3 is:

[0097] ; (2)

[0098] For the determined site category boundary area, select the applicable characteristic period general interpolation formula, including:

[0099] When the target working point ( , ) is located in the first vertical region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is:

[0100] ; (3)

[0101] When the target working point ( , ) is within the first horizontal region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is:

[0102] ; (4)

[0103] When the target working point ( , ) is located in the first vertical region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is:

[0104] ; (5)

[0105] When the target working point ( , ) is within the second horizontal area, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is:

[0106] ; (6)

[0107] Combining the above formulas (3) to (6), the characteristic period of the site boundary area is obtained: The general interpolation formula is:

[0108] .

[0109] After obtaining the general interpolation formula of the above characteristic period, the specific parameter values ​​in the interpolation formula are determined in combination with the design earthquake grouping of the target work point and the category of the site category boundary area where the target work point is located, and the characteristic period of the target work point is obtained by substituting them into the calculation.

[0110] The "General Code for Seismic Design of Buildings and Municipal Engineering" (GB55002-2021), "Code for Seismic Design of Buildings" (GB50011-2010) and other standards determine the thickness of the soil cover layer for different site categories. Values ​​at the boundary and equivalent shear wave velocity of the soil layer The values ​​at the boundary are shown in the following table: The thickness of the soil cover layer for Class I1, Class II, Class III and Class IV sites The values ​​at the boundary are 3m, 5m, 15m, 50m, and 80m respectively. The equivalent shear wave velocity of the soil layer at Class I1, Class II, Class III, and Class IV sites is The values ​​at the dividing line are 150m / s, 250m / s, and 500m / s. is the shear wave velocity of the rock.

[0111]

[0112] Soil cover thickness and the equivalent shear wave velocity of the soil layer Based on the value at the boundary line, solve the value of the site boundary line ±15% in turn, that is, when the boundary line When the value is 3m, the values ​​after ±15% are 2.55m and 3.45m respectively; When the value is 5m, the values ​​after ±15% are 4.25m and 5.75m respectively; When the value is 15m, the values ​​after ±15% are 12.75m and 17.25m respectively; When the value is 50m, the values ​​after ±15% are 42.5m and 57.5m respectively; When the value is 80m, the values ​​after ±15% are 68m and 92m respectively;

[0113] When the dividing line When the value is 150m / s, the values ​​after ±15% are 127.5m / s and 172.5m / s respectively; When the value is 250m / s, the values ​​after ±15% are 212.5m / s and 287.5m / s respectively; When the value is 500m / s, the values ​​after ±15% are 425m / s and 575m / s respectively. and shear wave velocity The boundary value of and and its range of ±15% are based on the thickness of the soil cover layer on the site. is the horizontal axis, and the equivalent shear wave velocity of the soil layer With the vertical axis as the reference, the boundary lines of Class I, Class II, Class III and Class IV sites can be drawn, and the area within the range of ±15% of the boundary line can be determined. Figure 1 shown The boundary line on the plane and its ±15% range can be drawn using this method.

[0114] Article 4.4.2 of the General Code for Seismic Resistance of Buildings and Municipal Engineering (GB55002-2021) states that the characteristic period should be adopted according to the site category and design earthquake grouping according to Table 2. When there are reliable shear wave velocities and cover layer thicknesses and their values ​​are within ±15% of the boundary of the site category listed in Table 1, the characteristic period should be determined by interpolation.

[0115]

[0116] Therefore, first determine the thickness of the soil cover layer at the target construction site. and the equivalent shear wave velocity of the soil layer , according to the coordinates formed by the work point ( , ) Determine the category of the site category boundary area where it is located, and substitute the relevant parameters into the general characteristic period interpolation formula in combination with the reference values ​​provided by the national normative documents in Tables 1 and 2 to calculate the characteristic period of the construction site. The following will explain in detail the specific determination method of each parameter in the general interpolation formula under different design earthquake groups and site category boundary area categories.

[0117] When the design earthquake group is in the first group, and the site category boundary area where the target construction point is located is the I1 and II site boundary area, that is, k=I1, k+1=II, the value of the relevant parameter is: , , = 0.1s, =3m, =5m, =250m / s, =500m / s;

[0118] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories I1 and II when the design earthquake group is in the first group. The interpolation formula is as follows:

[0119] ; (7)

[0120] The site category boundary area where the target work point is located is the site category boundary area of ​​Class II and Class III, that is, when k=II and k+1=III, the values ​​of the relevant parameters are: = 0.35s, =0.45s, = 0.1s, =15m, =50m, =150m / s, =250m / s;

[0121] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories II and III when the design earthquake group is in the first group. The interpolation formula is as follows:

[0122] ; (8)

[0123] The site category boundary area where the target work point is located is the site category boundary area of ​​category III and IV, that is, when k=III and k+1=IV, the value of the relevant parameter is: =0.45s, =0.65s, = 0.2s, =80m, =150m / s;

[0124] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories III and IV when the design earthquake group is in the first group. The interpolation formula is as follows:

[0125] ; (9)

[0126] When the design earthquake grouping changes, the parameters in the interpolation formula , , ,and Keep the parameters unchanged. , and Adjusted according to the different design earthquake groups combined with the "General Code for Seismic Resistance of Buildings and Municipal Engineering" (GB55002-2021). When the design earthquake group changes, the characteristic period of the upper and lower endpoints of L1 and L3 , This is because different earthquake groups correspond to different seismic intensity and frequency characteristics, which affects the parameter setting of the characteristic period. The design earthquake grouping reflects the difference in earthquake intensity and frequency: different groups (such as the first group, the second group, and the third group) correspond to different levels of seismic activity. The higher the level of seismic activity, the stronger the site's amplification effect on low-frequency seismic motion may be, so the characteristic period will be adjusted accordingly to reflect the seismic requirements of the design earthquake grouping.

[0127] The calculation of the characteristic period depends on the parameters in the site category and earthquake grouping. When the design earthquake grouping changes, the parameters in the interpolation formula will be adjusted accordingly so that the characteristic period of the upper and lower endpoints of L1 and L3 , and the reduction in the characteristic period Adjustments are also made to ensure that the calculation results meet the seismic requirements of the new design grouping.

[0128] When the design earthquake group is in the second group, and the site category boundary area where the target construction point is located is the I1 and II site category boundary area, that is, k=I1, k+1=II, the value of the relevant parameter is: = 0.30s, = 0.40s, =0.1s;

[0129] The site category boundary area where the target work point is located is the site category boundary area of ​​Class II and Class III, that is, when k=II and k+1=III, the values ​​of the relevant parameters are: = 0.40s, =0.55s, 0.15s;

[0130] The site category boundary area where the target work point is located is the site category boundary area of ​​category III and IV, that is, when k=III and k+1=IV, the value of the relevant parameter is: =0.55s, = 0.75s, 0.2s;

[0131] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to derive the characteristic period of the boundary area of ​​different site categories when the design earthquake group is in the second group. The general interpolation formula is as follows:

[0132] .

[0133] When the design earthquake group is in the third group, and the site category boundary area where the target construction point is located is the site category boundary area of ​​category I1 and II, that is, k=I1, k+1=II, the value of the relevant parameter is: = 0.35s, =0.45s, =0.1s;

[0134] The site category boundary area where the target work point is located is the site category boundary area of ​​Class II and Class III, that is, when k=II and k+1=III, the values ​​of the relevant parameters are: =0.45s, =0.65s, 0.2s;

[0135] The site category boundary area where the target work point is located is the site category boundary area of ​​category III and IV, that is, when k=III and k+1=IV, the value of the relevant parameter is: =0.65s, =0.9s, 0.25s;

[0136] Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to derive the characteristic period of the boundary area of ​​different site categories when the design earthquake group is in the third group. The general interpolation formula is as follows:

[0137] .

[0138] The characteristic period analysis method for seismic design of engineering structures provided by the present invention innovatively proposes a set of interpolation formulas applicable to site boundary areas in response to the problem of the lack of clear and specific characteristic period interpolation calculation formulas in the prior art. By comprehensively analyzing the design earthquake grouping of the target work point and the site category boundary area, combined with specific parameter settings, the calculation of the characteristic period is made more accurate, avoiding the error accumulation caused by drawing straight lines on a plane or manual judgment in the prior art. The characteristic period obtained through analysis is combined with the design requirements of the engineering project to optimize the seismic performance evaluation and design parameters of the structure to ensure the stability and safety of the design under earthquake action. This method avoids the error accumulation in traditional methods, provides a high-precision characteristic period analysis based on actual geological data, is particularly suitable for seismic design of site boundary areas, and effectively improves the accuracy and safety of seismic design of engineering structures.

[0139] Embodiment 2:

[0140] In order to further illustrate the characteristic period analysis method for seismic design of engineering structures provided by the present invention, the calculation of the characteristic period of a certain engineering project is described in detail below in combination with a specific application scenario.

[0141] A certain project is to build a 2-story reinforced concrete frame structure complex located in Ganyu District, Lianyungang City, Jiangsu Province. After investigating the area where the project is located, it was determined based on geological survey data that the seismic design earthquake group of the project site is the third group, the site cover thickness is 36 meters, and the equivalent shear wave velocity of the soil layer is 160m / s. In order to meet the seismic design requirements of the engineering structure, it is necessary to accurately calculate the characteristic period of the site.

[0142] According to the characteristic period analysis method for seismic design of engineering structures provided by the present invention, the target work site is first investigated to determine that its design earthquake group is the third group, and the site category dividing line area where it is located is the dividing line area between Class II and Class III sites; then, an applicable characteristic period interpolation formula is selected for the dividing line area; finally, based on the earthquake grouping and site category of the project, the relevant parameter values ​​in the interpolation formula are determined and substituted into the calculation to obtain the required characteristic period.

[0143] The specific steps are as follows:

[0144] First, conduct a site survey at the project site. According to the geological survey data, the design earthquake group of the project is determined to be the third group. The site cover thickness is 36 meters and the equivalent shear wave velocity of the soil layer is 160m / s. Use the site cover thickness and the equivalent shear wave velocity of the soil layer as the horizontal and vertical coordinates, respectively, to establish the site parameter coordinate point (36,160), and place the coordinate point at According to the position of the coordinate point (36,160) in the figure, it is judged that the relevant parameters of the site are located in the first horizontal area surrounded by points C, D, E, and F in the boundary area between Class II and Class III sites.

[0145] Should The plane boundary line ±15% range diagram can use existing charts, or be drawn based on the boundary line values ​​provided in the "General Code for Seismic Resistance of Buildings and Municipal Engineering" GB55002-2021, with the site cover layer thickness as the horizontal axis and the equivalent shear wave velocity of the soil layer as the vertical axis.

[0146] Finally, based on the known design earthquake grouping, site category boundary area category and the specific location of the area, the corresponding third group of design earthquake grouping, Class II and Class III site boundary area, and characteristic period calculation formula in the first horizontal area are selected to complete the characteristic period calculation of the target work point.

[0147] The corresponding characteristic period calculation formula is:

[0148] ;

[0149] Will =160m / s Substituting into the above formula, we can get the characteristic period of the site for:

[0150] s.

[0151] The calculated characteristic period can play a key role in the seismic design of engineering structures. First, the seismic response spectrum curve of the site is determined according to the characteristic period of the target work point. This curve is used to describe the seismic acceleration amplification effect under different periods. Specifically, by substituting the characteristic period into the response spectrum formula in the "Code for Seismic Design of Buildings", the seismic acceleration value of the site under different vibration periods can be obtained, thereby providing accurate seismic load input data for the seismic design of engineering structures.

[0152] Secondly, by comparing the characteristic period with the natural vibration period of the building, it is possible to assess whether the structure has a resonance risk. If it is found that the natural vibration period of the building is close to the characteristic period of the site, its natural vibration period can be changed by adjusting the building height, stiffness or mass distribution to avoid the earthquake amplification effect. At the same time, the characteristic period also directly affects the foundation design, structural stiffness distribution and component design. For example, for sites with a large characteristic period, it may be necessary to select a flexible foundation to reduce the transmission of seismic forces, or optimize the bearing capacity distribution of beams, columns and shear walls in the structural design to improve the overall seismic performance.

[0153] Finally, after the preliminary design is completed, the characteristic period can also be used to verify the seismic performance. Combined with the earthquake response spectrum, the seismic response characteristics of the building are analyzed, including the maximum displacement, inter-story displacement angle, and acceleration response. If the verification results do not meet the requirements of the specification, the design plan can be readjusted according to the characteristic period to ensure the stability and safety of the structure under earthquake action. Through the above steps, the calculation and application of the characteristic period runs through all aspects of the seismic design of engineering structures, significantly improving the accuracy and scientificity of the design.

[0154] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A characteristic period analysis method for seismic design of engineering structures, characterized in that: include: Conduct an investigation on the target construction site to determine the design earthquake grouping of the target construction site, the site category boundary area where the target construction site is located, and the category of the site category boundary area, wherein the site category boundary area is the area within ±15% of the site category boundary; For the determined site category boundary area, select the applicable characteristic period interpolation formula; Based on the design earthquake grouping of the target work point and the category of the site category boundary area where the target work point is located, the parameter values ​​in the interpolation formula are determined and substituted into the calculation of the characteristic period of the target work point.

2. The characteristic period analysis method for seismic design of engineering structures according to claim 1, characterized in that: Determine the design earthquake group of the target construction site and the site category boundary area where the target construction site is located, including: Determine the design earthquake grouping of the target construction point based on the seismic activity level and seismic motion parameters of the area where the target construction point is located; and site cover thickness , determine the target working point at Coordinates of the boundary line and its ±15% range in the plane ( , ), and accordingly determine the site category boundary area where the target work point is located; The design earthquake groups are divided into a first group, a second group and a third group; The site categories are divided into Class I1, Class II, Class III and Class IV; The site category boundary area is divided into the boundary area between Class I1 and Class II sites, the boundary area between Class II and Class III sites, and the boundary area between Class III and Class IV sites.

3. The characteristic period analysis method for seismic design of engineering structures according to claim 1 is characterized in that: Areas within ±15% of the site category boundaries include: The first vertical area is surrounded by points A, B, C, and D; the first horizontal area is surrounded by points C, D, E, and F; the second vertical area is surrounded by points E, F, G, and H; the second horizontal area is surrounded by points G, H, J, and K; The site category boundary line in the first vertical area, the boundary line formed by ±15% of the site category boundary line and The horizontal axis of the plane dividing line and its ±15% range The intersecting horizontal coordinates are , , ; The site category boundary line within the first horizontal area, the boundary line formed by ±15% of the site category boundary line and The vertical axis of the plane dividing line and its ±15% range The intersecting ordinates are , , ; The site category boundary line in the second vertical area, the boundary line formed by ±15% of the site category boundary line and The horizontal axis of the plane dividing line and its ±15% range The intersecting horizontal coordinates are , , ; The site category boundary line in the second horizontal area, the boundary line formed by ±15% of the site category boundary line and The vertical axis of the plane dividing line and its ±15% range The intersecting ordinates are , , ; The common edge between the first vertical area and the first horizontal area is L1, the common edge between the first horizontal area and the second vertical area is L2, and the common edge between the second vertical area and the second horizontal area is L3; the site category dividing line separates the site areas of different categories, the area category above the dividing line is set to k, where k is Class I1, Class II or Class III, and the area category below the dividing line is set to k+1, where k+1 is Class II, Class III or Class IV; L1~L3 are three finite spatial straight lines, defined in the coordinate system ( , , ), among which is the characteristic period; as the thickness of the site covering layer The decrease of soil equivalent shear wave velocity The characteristic cycle is increasing. It shows a linear decreasing trend; L1~L3 have upper and lower endpoints respectively; the characteristic period of the lower and upper endpoints of L1~L3 from Linearly decreases to , the reduction is , represents the characteristic period of the lower endpoint of site category k+1, Indicates the characteristic period of the upper endpoint of site category k, the same characteristic period The points on the line are connected to form a Contour lines; in, , , , As shown below: 。 4. The characteristic period analysis method for seismic design of engineering structures according to claim 3 is characterized in that: The characteristic period general interpolation formula is solved by interpolating the point-wise equations of the spatial lines L1 and L3. The point-wise equations of L1, L2 and L3 are related to the thickness of the site cover layer. , soil equivalent shear wave velocity , characteristic period The three-dimensional variable equation ( , , ); L1 is a straight line defined by the lower endpoint C and the upper endpoint D. The coordinates of point C and point D are: C (1.15 , 0.85 , )、D(0.85 , 1.15 , ), L1 direction vector =(0.3 , -0.3 , ), L1 is represented by the point D, and the direction vector is The space straight line, ( , , ) represents the coordinates of a point on L1, then the point-wise equation of L1 is: ；（1） L3 is a straight line defined by the lower endpoint G and the upper endpoint H. The coordinates of point G and point H are: G (1.15 , 0.85 , )、H(0.85 , 1.15 , ), L3 direction vector =(0.3 , -0.3 , ), L3 is represented by the point H, and the direction vector is The space straight line, ( , , ) represents the coordinates of a point on L3, then the point-wise equation of L3 is: ； （2） For the determined site category boundary area, select the applicable characteristic period general interpolation formula, including: When the target working point ( , ) is located in the first vertical region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is: ；（3） When the target working point ( , ) is within the first horizontal region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is: ；（4） When the target working point ( , ) is located in the first vertical region, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is: ； （5） When the target working point ( , ) is within the second horizontal area, The value of , substituting into formula (1) to obtain the characteristic period The interpolation formula is: ；（6） Combining the above formulas (3) to (6), the characteristic period of the site boundary area is obtained: The general interpolation formula is: 。 5. The characteristic period analysis method for seismic design of engineering structures according to claim 4 is characterized in that: Based on the design earthquake grouping of the target construction point and the category of the site category boundary area where the target construction point is located, the parameter values ​​in the interpolation formula are determined, including: When the design earthquake group is the first, second or third group, and the target construction site is located in the boundary area between the I1 and II sites, set the parameters k=I1, k+1=II, and determine the parameter values ​​in the interpolation formula in combination with the reference values ​​provided in the General Code for Seismic Resistance of Buildings and Municipal Engineering GB55002-2021; When the target work site is located in the boundary area between Class II and Class III sites, set the parameters k=II, k+1=III, and determine the parameter values ​​in the interpolation formula in combination with the reference values ​​in the specification; When the target work site is located in the boundary area between Class III and Class IV sites, set the parameters k=III, k+1=IV, and determine the parameter values ​​in the interpolation formula in combination with the reference values ​​in the specification; The parameters include: , , , , , , ; When the design earthquake grouping changes, the parameters in the interpolation formula , , ,and Keep the parameters unchanged. , and It will be adjusted according to different design earthquake groups in combination with the "General Code for Seismic Resistance of Buildings and Municipal Engineering" GB55002-2021.

6. The characteristic period analysis method for seismic design of engineering structures according to claim 5 is characterized in that: When the design earthquake group is in the first group and the target construction site is located in the boundary area between Class I1 and Class II sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​provided in the General Code for Seismic Resistance of Buildings and Municipal Engineering GB55002-2021, including: , , =0.1s, =3m, =5m, =250m / s, =500m / s; Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories I1 and II when the design earthquake group is in the first group. The interpolation formula is as follows: ；（7） When the target construction site is located in the boundary area between Class II and Class III sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including: =0.35s, =0.45s, =0.1s, =15m, =50m, =150m / s, =250m / s; Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories II and III when the design earthquake group is in the first group. The interpolation formula is as follows: ；（8） When the target construction site is located in the boundary area between Class III and Class IV sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including: =0.45s, =0.65s, =0.2s, =80m, =150m / s; Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to obtain the characteristic period of the boundary area between site categories III and IV when the design earthquake group is in the first group. The interpolation formula is as follows: ；（9） Combining the above formulas (7) to (9), it is concluded that when the design earthquake group is in the first group, the characteristic period of the boundary area of ​​different site categories is The general interpolation formula is as follows: 。 7. The characteristic period analysis method for seismic design of engineering structures according to claim 6 is characterized in that: When the design earthquake group is in the second group and the target construction site is located in the boundary area between Class I1 and Class II sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​provided in the General Code for Seismic Resistance of Buildings and Municipal Engineering GB55002-2021, including: =0.30s, =0.40s, =0.1s; When the target construction site is located in the boundary area between Class II and Class III sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including: =0.40s, =0.55s, 0.15s; When the target construction site is located in the boundary area between Class III and Class IV sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including: =0.55s, =0.75s, 0.2s; Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula is used to derive the characteristic period of the boundary area of ​​different site categories when the design earthquake group is in the second group. The general interpolation formula is as follows: 。 8. The characteristic period analysis method for seismic design of engineering structures according to claim 5, characterized in that: When the design earthquake group is in the third group and the target construction site is located in the boundary area between Class I1 and Class II sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​provided in the General Code for Seismic Resistance of Buildings and Municipal Engineering GB55002-2021, including: =0.35s, =0.45s, =0.1s; When the target construction site is located in the boundary area between Class II and Class III sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including: =0.45s, =0.65s, 0.2s; When the target construction site is located in the boundary area between Class III and Class IV sites, the parameter values ​​in the interpolation formula are determined in combination with the reference values ​​in the specification, including: =0.65s, =0.9s, 0.25s; Substitute the above parameter values ​​into the characteristic period of the site boundary area The general interpolation formula of the site classification boundary area shows that when the design earthquake group is in the third group, the characteristic period of the site classification boundary area is The general interpolation formula is as follows: 。

Images