A method for determining structural seismic performance index considering earthquake motion characteristics

Abstract

The method for determining the seismic performance index of a structure considering the characteristics of earthquake motion of the present invention comprises the following steps: S1, selecting the same number of special earthquake motions and ordinary earthquake motions; S2, selecting an inelastic SDOF system, and calculating the elastic-plastic displacement response process of the SDOF system under the action of earthquake motion; S3, determining the loading mode of the special earthquake motion based on the characteristics of the special earthquake motion; S4, analyzing the variation law of key parameters with the dynamic characteristics of the structure in different loading modes; S5, analyzing the influence law of key parameters on the seismic performance index of structural components through quasi-static tests and numerical simulations; S6, establishing the relationship between the seismic performance index of structural components and key parameters under the quasi-static loading mode; S7, determining the seismic performance index limit of the structural components considering the influence of the characteristics of special earthquake motion based on steps S4 and S6. The method of the present invention solves the problems of uncertainty, low efficiency and unsuitability of the traditional test loading system for special earthquake motion analysis in the existing quasi-static tests.

Description

Technical Field

[0001] The present invention relates to the field of engineering earthquake resistance technology, and in particular to a method for determining a structural earthquake resistance performance index taking into account earthquake motion characteristics. Background Art

[0002] Determining the seismic performance index of structural components is one of the important contents of performance-based seismic design theory. The purpose of determining the performance index of components is to analyze the seismic performance of RC components under earthquakes from a quantitative perspective. Conducting quasi-static tests on structural components is the basis for analyzing the factors affecting the seismic performance of structural components and determining the limits of seismic performance indexes. Through quasi-static tests and finite element analysis, important information such as strength, stiffness, deformation, and energy consumption of structural components can be effectively obtained, thus providing a basis for quantifying the seismic performance of structural components. Under the action of special earthquake motion, the displacement response of the structure often shows different response characteristics from those under the action of ordinary earthquake motion. For example, the seismic response of a structure with a long natural vibration period under the action of far-field long-period earthquake motion is significantly greater than that under the action of ordinary earthquake motion. The structural displacement response time history shows the characteristics of multiple large displacement reciprocating cycles and long duration. Under the action of near-fault pulse earthquake motion, the structure will have an initial pulse response, which reflects the action characteristics of far-field long-period earthquake motion and near-fault pulse earthquake motion that are different from ordinary earthquake motion. In essence, it is due to the different action paths of different earthquake motions on structural components. The action paths can be reflected by the loading modes in quasi-static tests and finite element methods, but the loading modes used in the existing quasi-static tests do not effectively consider special earthquake motions. Regarding the characteristics of earthquake motion, scholars at home and abroad have carried out the analysis of quasi-static test loading systems considering the special characteristics of earthquake motion, and completed the quasi-static test research on structural components. However, the adopted quasi-static loading system is a subjectively determined loading system on the one hand, lacking a theoretical basis. On the other hand, after complex theoretical analysis, it cannot be coordinated and unified with the traditional quasi-static loading system (three cycles or two cycles). In addition, the characteristics of earthquake motion are closely related to the dynamic characteristics of the structure, especially the period. It is difficult to effectively reflect the influence of the characteristics of earthquake motion by using a single loading system, which is inconsistent with the actual situation. Due to the complexity and diversity of the structural dynamic characteristics, if the seismic performance of a specific structure under special earthquake motion is to be analyzed, a specific loading system needs to be established for experimental research, which is troublesome and inefficient.

[0003] Therefore, it is necessary to propose an efficient method to determine the seismic performance index of structural components that can take into account the influence of special seismic action characteristics, so as to ensure the seismic safety of structural components under special seismic action. Summary of the invention

[0004] The technical solution of the present invention is to solve the problem that the existing method for determining the seismic performance index of structural components does not take into account the influence of special earthquake motion characteristics and cannot ensure the seismic safety of structural components under special earthquake motion.

[0005] In order to solve the above problems, the present invention provides a method for determining a structural seismic performance index taking into account the characteristics of earthquake action, comprising the steps of:

[0006] S1. According to the method for distinguishing special types of earthquake motion, select the same number of special earthquake motions and common earthquake motions.

[0007] S2. Select inelastic SDOF systems with different dynamic characteristics respectively, calculate the elastic-plastic displacement response process of the SDOF system under different earthquake motions, compare and analyze the elastic-plastic displacement cyclic distribution characteristics of the SDOF system under special earthquake motions and ordinary earthquake motions, and obtain the action characteristics of special earthquake motions;

[0008] S3. Based on the analysis of the characteristics of special earthquake action, determine the quasi-static loading mode that can reflect the characteristics of special earthquake action;

[0009] S4. Statistically analyze the number of displacement cycles and amplitude distribution under different SDOF systems, and analyze the variation of key parameters with structural dynamic characteristics under different loading modes;

[0010] S5. Through quasi-static tests and numerical simulations, comparative analysis is made on the influence of key parameters in quasi-static loading mode on the seismic performance indicators of structural components;

[0011] S6. Establish the relationship between the seismic performance index of the structural components under the quasi-static loading mode and the key parameters in the quasi-static loading mode;

[0012] S7. According to the basic natural vibration period of the structure in the actual project, the relationship between the key parameters in the loading mode and the structural dynamic characteristics is determined based on step S4, and then combined with step S6, the seismic performance index limit of the structural component considering the influence of the special seismic action characteristics is determined.

[0013] Furthermore, in step S2, the elastic-plastic displacement response process of the SDOF system under different earthquake motions is calculated, and the iterative stop point of the PGA amplitude modulation is when the structural bearing capacity drops to 85% of the peak bearing capacity. The specific steps are as follows:

[0014] First, different earthquake actions are applied to the SDOF system, and the elastic-plastic displacement and bearing capacity data of the SDOF system are obtained by solving the structural motion equation:

[0015]

[0016] In the formula, and μ represent the normalized acceleration, velocity and displacement of the SDOF system respectively; ξ is the damping ratio of the SDOF system; ω is the natural frequency of the SDOF system; α is the stiffness ratio before and after the structural yield, and its value is between 0 and 1; is the ground acceleration; δ y is the yield displacement of the structure; where it involves the hysteresis displacement μ defined by the first-order differential equation z , as shown below:

[0017]

[0018] In the formula, is the hysteresis velocity, A, β, γ and n are the shape parameters of the hysteresis curve; v, η and h (μ z ) respectively describe the strength degradation, stiffness degradation and pinching effect, and are obtained by the following formula:

[0019] v=1+δ v ε (3)

[0020] η=1+δ η ε (4)

[0021]

[0022] in:

[0023] ζ 1 =ξ s [1-exp(-pε)] (6)

[0024] ζ 2 =(ψ+δ ψ ε)(λ+ζ 1 ) (7)

[0025]

[0026] In the formula, δ η and δ v are strength and stiffness degradation parameters respectively; ξ s ,ψ,δ ψ , λ, q and p are pinching effect parameters, where ξ s Controls the total slip, ψ controls the pinching amplitude, δ ψ is the pinching rate, λ is the interaction coefficient between pinching severity and pinching rate, q controls the starting position of pinching, and p is the pinching slope; is a sign function related to speed, when hour, are 1, 0 and -1 respectively; ε is the accumulated hysteresis energy dissipation in the time history T, which is defined by the following formula:

[0027]

[0028]

[0029] The high-order differential equation of formula (1) is transformed into a first-order differential equation system, as shown in formula (10), and the initial value condition is formula y 1 =0,y 2 =0,y 3 =0,y 4 = 0, so the fourth-order Runge-Kutta method can be used to solve the motion equation of the SDOF system with the bearing capacity model of BWBN.

[0030] After solving the equation of motion, we get the bearing capacity data F(t) = αω 2 μ-(1-α)ω 2 μ z By analyzing the bearing capacity data, the bearing capacity at the maximum displacement and the peak bearing capacity are obtained. If the bearing capacity at the maximum displacement does not drop to 85% of the peak bearing capacity, the PGA of the seismic motion is adjusted to recalculate the elastic-plastic response of the SDOF system, and the acceleration amplitude PGA of each seismic motion is gradually increased from 0 to 1gal until the relative error between the bearing capacity at the maximum displacement of the structural component and 85% of the peak bearing capacity is less than or equal to 0.1%. The iteration is stopped.

[0031] Furthermore, in step S2, the elastic-plastic displacement cyclic distribution characteristics of the SDOF system under the action of special earthquake motion and ordinary earthquake motion are compared and analyzed. The action characteristics of the special earthquake motion can be obtained by comparing indicators such as the number of cycles and pulse amplitude characteristics in the elastic-plastic displacement cyclic distribution under different SDOF systems.

[0032] Furthermore, the quasi-static loading mode of the special earthquake action characteristics in step S3 is: based on the analysis of the special earthquake action characteristics, a loading mode that can reflect the special earthquake action characteristics and is coordinated with the traditional quasi-static loading system is established, that is, a loading mode that combines key parameters with the traditional quasi-static loading system is formed.

[0033] Furthermore, in step S3, when the key parameters of the quasi-static loading mode of the special earthquake action characteristics are determined, it is equivalent to determining a specific quasi-static loading system. Different key parameters under the same loading mode correspond to a series of different quasi-static loading systems.

[0034] Furthermore, the specific steps of analyzing the variation of key parameters with structural dynamic characteristics in different loading modes in step S4 are as follows:

[0035] Different loading modes include: traditional loading mode and quasi-static loading mode.

[0036] The relationship between key parameters and basic natural vibration period of the structure in different loading modes is analyzed based on the rain flow counting method, and the average number of pre-peak inelastic displacement cycles N of the SDOF system under special ground motion and ordinary ground motion in different loading modes is calculated. p, the maximum displacement average value u max Equal response characteristic parameters, and analyze the corresponding relationship between their structural dynamic characteristics, where N p Related to the number of cycles in the amplified cyclic loading mode, u max The ratio k of the average number of inelastic cycles of the SDOF system with a natural vibration period of 0.5 to 10 s under special ground motion and ordinary ground motion is obtained in relation to the pulse amplitude in the “pulse + traditional amplification cycle” loading mode. N =N p，S / N p，O , and the average value u of the pulse displacement response of the SDOF system with a natural vibration period of 0.5 to 10 s under special earthquake motion max，S , and establish k N 、u max，S The relationship between k and the basic natural vibration period of the structure is: N =f 1 (T),u max，S =f 2 (T).

[0037] Furthermore, the specific steps of establishing the relationship between the seismic performance index of the structural component under the pseudo-static loading mode and the key parameters in the pseudo-static loading mode in step S6 are:

[0038] Through quasi-static tests and numerical simulations, the influence of key parameters in quasi-static loading mode on the seismic performance indicators of structural components is quantitatively analyzed. It is concluded that the seismic performance indicators of structural components mainly include: bearing capacity F max , ductility coefficient μ, equivalent stiffness K at each displacement amplitude, equivalent viscous damping coefficient h e .

[0039] The seismic performance indexes vary with the number of cycles N and pulse cycle amplitude δ of each displacement amplitude s The changing relationships are: F max，N =f 11 (N) μ N =f 21 (N) K N =f 31 (N) h e，N =f 41 (N)

[0040] Furthermore, in step S7, based on the relationship between the key parameters in the loading mode and the structural dynamic characteristics determined in step S4, and in combination with step S6, the specific steps for determining the seismic performance index of the structural component considering the influence of the special earthquake action characteristics are as follows:

[0041] N=k obtained in step S4 N ×N 传统 =f 1 (T)×N 传统 Substitute F max，N =f 11 (N), μ N =f 21 (N), K N =f 31 (N), h e，N =f 41 (N), and the relationship between the natural vibration period of the structure and the seismic performance index of the structural components considering the influence of the long-period earthquake action characteristics in the far field is obtained: F max，N =F 11 (T), μ N =F 21 (T), K N =F 31 (T), h e，N =F 41 (T), where N 传统 is the number of cycles for each level of cycle amplitude in the traditional quasi-static loading system;

[0042] Based on the seismic performance index of the component obtained in step S6, the large displacement pulse cycle amplitude δ s The relationship of the change is to replace the δ obtained in step S4 with s =u max，S =f 2 (T) Substitution The relationship between the natural vibration period of the structure and the seismic performance index of the structural components considering the influence of the characteristics of the near-fault pulse ground motion is obtained:

[0043]

[0044] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art. The present invention provides a method based on the displacement response of a single-degree-of-freedom system under special earthquake motion, systematically analyzes the action characteristics of special earthquake motion that are different from ordinary earthquake motion, and obtains a quasi-static loading mode on the basis of the ordinary loading mode by comparing ordinary earthquake motion with special earthquake motion, and according to the influence of relevant indicators on the seismic performance indicators of structural components under different loading modes, obtains the seismic performance index limit under the method of efficiently determining the seismic performance index of structural components considering the influence of special earthquake motion action characteristics. The uncertainty of the use of subjective factors to determine the loading control index in the existing quasi-static test, the inability of the traditional loading system to reflect the special earthquake motion action characteristics, and the seismic performance index of the structural components determined based on the traditional quasi-static test loading system is not suitable for the seismic performance analysis of the structure under the special earthquake motion, and provides a new idea for the determination method and safety assessment of the seismic performance index of the structural components under the special earthquake motion. At the same time, the method can be applied to different types of structural components, and the process is simple and has wide applicability. It is of great significance for the seismic analysis and design of structures considering the influence of special earthquake motion and the seismic performance evaluation of existing structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flow chart of a method for determining the seismic performance index of a component taking into account the characteristics of earthquake motion action of the present invention;

[0046] Figure 2 : are the elastic-plastic displacement response time history calculation diagrams of the inelastic SDOF system for different earthquake motions in the present invention, wherein (a) is the elastic-plastic displacement response time history calculation diagram of the inelastic SDOF system for ordinary earthquake motion, (b) is the elastic-plastic displacement response time history calculation diagram of the inelastic SDOF system for far-field long-period earthquake motion, and (c) is the elastic-plastic displacement response time history calculation diagram of the inelastic SDOF system for near-fault pulse earthquake motion;

[0047] Figure 3 is a time history curve diagram of the elastic-plastic displacement response of the SDOF system under different earthquake motions obtained in the embodiment of the present invention;

[0048] Figure 4 is a diagram of a loading device used in a quasi-static test in an embodiment of the present invention;

[0049] Figure 5 Different loading mode diagrams considering the action characteristics of special earthquakes in the quasi-static test in the embodiments of the invention, wherein (a) is a traditional loading mode diagram, (b) is an amplified cycle loading mode diagram, and (c) is a "pulse + traditional amplified cycle" loading mode diagram.

[0050] Among them: reaction beam-1; hydraulic jack-2; displacement meter-3; MTS actuator-4; reaction frame-5. DETAILED DESCRIPTION

[0051] A method for determining the seismic performance index of a component taking into account the characteristics of earthquake motion action according to the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0052] Combined with Figure 1 As shown, the present invention provides a method for determining the seismic performance index of a component considering the characteristics of earthquake action, which specifically includes the following seven steps:

[0053] Step 1: According to the method for distinguishing special types of earthquake motions, select the same number of special earthquake motions and common earthquake motions. Specifically, the special earthquake motions can be judged by earthquake motion characteristic indicators, such as PGA, PGV, PGD, response spectrum characteristics, time history characteristics, etc.

[0054] Step 2: Select the inelastic SDOF systems of special earthquake motion and common earthquake motion respectively, determine their dynamic characteristic parameters, calculate the elastic-plastic displacement response process of the SDOF system under different earthquake motions, compare and analyze the elastic-plastic displacement cyclic distribution characteristics of the SDOF system under special earthquake motion and common earthquake motion, and obtain the action characteristics of special earthquake motion.

[0055] Select an inelastic single degree of freedom (SDOF) system, determine its dynamic characteristic parameters, and calculate the elastic-plastic displacement response time history of the SDOF system under different earthquake motions. The calculation process is as follows: Figure 2 As shown in the figure, the elastic-plastic displacement response time history curves of the structure under different earthquake motions are obtained, and the elastic-plastic displacement cyclic distribution characteristics of the SDOF system under special earthquake motions and ordinary earthquake motions are compared and analyzed to obtain the action characteristics of special earthquake motions. The dynamic characteristics of the SDOF system are as follows: Under normal circumstances, the period range of the SDOF structure can be taken as 0.5 to 10s, the damping ratio of the SDOF structure can be taken as 5%, 6%, 7%, 8%, and 9%, and the hysteresis model of the SDOF system is selected as the BWBN restoring force model.

[0056] When calculating the elastic-plastic displacement time-history response, the iterative stop point of PGA modulation is when the structural bearing capacity drops to 85% of the peak bearing capacity. The specific process is as follows:

[0057] First, the earthquake motion is applied to the SDOF system, and the elastic-plastic displacement and bearing capacity data of the structure are obtained by solving the structural motion equation:

[0058]

[0059] In the formula, and μ represent the normalized acceleration, velocity and displacement of the SDOF system respectively; ξ is the damping ratio of the SDOF system; ω is the natural frequency of the SDOF system; α is the stiffness ratio before and after the structural yield, and its value is between 0 and 1; is the ground acceleration; δ y is the yield displacement of the structure. It involves the hysteresis variable μ defined by the first-order differential equation z , as shown in formula (2).

[0060]

[0061] In the formula, is the hysteresis velocity, A, β, γ and n are the shape parameters of the hysteresis curve; v, η and h (μ z ) respectively describe the strength degradation, stiffness degradation and pinching effect, and are determined by equations (3) to (5).

[0062] v=1+δ v ε (3)

[0063] η=1+δ η ε (4)

[0064]

[0065] in:

[0066] ζ 1 =ξ s [1-exp(-pε)] (6)

[0067] ζ 2 =(ψ+δ ψ ε)(λ+ζ 1 ) (7)

[0068]

[0069] Where: η and δ v are strength and stiffness degradation parameters respectively; ξ s ,ψ,δ ψ , λ, q and p are pinching effect parameters. Among them, ξ s Controls the total slip, ψ controls the pinching amplitude, δ ψ is the pinch rate, λ is the interaction coefficient between pinch severity and pinch rate, q controls the starting position of pinch, and p is the pinch slope. is a sign function related to speed, when hour, They are 1, 0 and -1 respectively; ε is the accumulated hysteresis energy dissipation in the time series T, which is defined by the following formula;

[0070]

[0071]

[0072] The high-order differential equation of formula (1) is transformed into a first-order differential equation system, as shown in formula (10), and the initial value condition is formula y 1 =0,y 2 =0,y 3 =0,y 4 = 0. In this way, the fourth-order Runge-Kutta method can be used to solve the motion equations of the SDOF system with the bearing capacity model of BWBN.

[0073] After solving the equation of motion, we get the bearing capacity data F(t) = αω 2 μ-(1-α)ω 2 μ z By analyzing the bearing capacity data, the bearing capacity at the maximum displacement and the peak bearing capacity are obtained. If the bearing capacity at the maximum displacement does not drop to 85% of the peak bearing capacity, the PGA of the seismic motion is adjusted to recalculate the elastic-plastic response of the SDOF system, and the acceleration amplitude PGA of each seismic motion is gradually increased from 0 to 1gal until the relative error between the bearing capacity at the maximum displacement of the structural component and 85% of the peak bearing capacity is less than or equal to 0.1%. The iteration is stopped.

[0074] According to an embodiment of the present invention, after each type of earthquake motion calculation is completed, the inelastic displacement response characteristics of the structure are analyzed to obtain the earthquake action characteristics of the special earthquake motion.

[0075] Step 3: Based on the analysis of earthquake motion characteristics, determine the quasi-static loading mode that can reflect the special earthquake motion characteristics.

[0076] Based on the analysis of the special earthquake action characteristics, a loading mode that can reflect the special earthquake action characteristics and is coordinated with the traditional quasi-static loading system is established, and the traditional static loading system is the standard loading system. The core idea is to consider the action characteristics of special earthquake motion on the basis of the traditional quasi-static loading system, so that the traditional quasi-static loading system becomes a special case in the constructed loading mode that can reflect the action characteristics of special earthquake motion. For example, the amplification cycle loading mode is applicable to the far-field long-period earthquake motion, in which the number of cycles is the key parameter, and when the number of cycles is 3, it is the traditional quasi-static loading system; the "pulse + traditional quasi-static loading system" loading mode is applicable to the near-fault pulse earthquake motion, in which the pulse amplitude is the key parameter, and when the pulse amplitude is zero, it is the traditional quasi-static loading system. For a specific quasi-static loading mode, when the key parameters are determined, it is equivalent to determining a specific quasi-static loading system. Different parameters under the same loading mode correspond to a series of different quasi-static loading systems.

[0077] Step 4: Statistically analyze the number of displacement cycles and amplitude distribution under different SDOF systems, and analyze the change patterns of key parameters with structural dynamic characteristics in different loading modes.

[0078] Specifically, by statistically analyzing the number of displacement cycles and amplitude distribution under different SDOF systems, and analyzing the variation of key parameters in loading modes with the dynamic characteristics of the structure, the relationship between the two is established.

[0079] Specifically, the relationship between the key parameters in the loading mode and the basic natural vibration period of the structure is analyzed based on the rain flow counting method. The average number of cycles of the pre-peak inelastic displacement of the SDOF system under the special ground motion and the ordinary ground motion related to the loading mode is calculated. p , the maximum displacement average value u max The corresponding relationship between the response characteristic parameters and the basic natural vibration period of the structure is analyzed, where N p Related to the number of cycles in the amplified cyclic loading mode, u max The ratio k of the average number of inelastic cycles of the SDOF system with a natural vibration period of 0.5 to 10 s under special ground motion and ordinary ground motion is obtained. N =N p，s / N p，O , and the average value u of the pulse displacement response of the SDOF system with a natural vibration period of 0.5 to 10 s under special earthquake motion max，S , and establish k N 、u max，S The mathematical relationship between the basic natural vibration period of the structure k N =f 1 (T),u max，S =f 2 (T).

[0080] Step 5: Through quasi-static tests and numerical simulations, compare and analyze the influence of key parameters in the quasi-static loading mode on the seismic performance indicators of structural components.

[0081] Specifically, by comparing and analyzing the influence of key parameters in loading modes on the seismic performance of structural components, quasi-static tests and numerical simulations of structural components that consider the influence of relevant indicators in loading modes are conducted, and the influence of relevant indicators in loading modes on the seismic performance indicators of structural components is considered in quasi-static tests and numerical simulations. For example, for far-field long-period seismic motions, the focus is on analyzing the influence of the number of cycles on the seismic performance indicators of structural components; for near-fault pulse-type seismic motions, the focus is on analyzing the influence of the pulse amplitude on the seismic performance indicators of structural components.

[0082] Step 6: Establish the relationship between the seismic performance index of structural components under the quasi-static loading mode and the key parameters in the quasi-static loading mode.

[0083] Specifically, combined with the quasi-static test and numerical simulation, the influence of key parameters in the loading mode on the seismic performance index of structural components is quantitatively analyzed, and it is proposed that the seismic performance index of structural components mainly includes: bearing capacity F max , ductility coefficient μ, equivalent stiffness K at each displacement amplitude, equivalent viscous damping coefficient h e ,

[0084] Specifically, the seismic performance index of structural components varies with the number of cycles N of each displacement amplitude and the pulse cycle amplitude δ s The relationship between the changes is F max，N =f 11 (N) μ N =f 21 (N) K N =f 31 (N) h e，N =f 41 (N)

[0085] Step 7. According to the basic natural vibration period of the structure in the actual project, the relationship between the key parameters in the loading mode and the structural dynamic characteristics is determined based on step 4, and then combined with step 6, the seismic performance index limit of the structural component considering the influence of special seismic action characteristics is determined.

[0086] Specifically, based on the relationship between the component seismic performance index and the number of cycles N of each level of displacement amplitude obtained in step 6, N=k obtained in step 4 is replaced by N ×N 传统 =f 1 (T)×N 传统 Substitute F max，N =f 11 (N), μ N =f 21 (N), K N =f 31 (N), h e，N =f 41 (N), and the relationship between the natural vibration period of the structure and the seismic performance index of the structural components considering the influence of the long-period earthquake action characteristics in the far field is obtained. max，N =F 11 (T), μ N =F 21 (T), K N =F 31 (T), h e，N =F41 (T), where N 传统 is the number of cycles for each level of cycle amplitude in the traditional quasi-static loading system;

[0087] Based on the seismic performance index of the component obtained in step 6, the large displacement pulse cycle amplitude δ s The relationship of change is to replace the δ obtained in step 4 with s =u max，S =f 2 (T) Substitution The relationship between the natural vibration period of the structure and the seismic performance index of the structural components considering the characteristics of the near-fault pulse ground motion is obtained.

[0088] In order to more clearly describe the use and advantages of the method of the present invention, the method of the present invention will be explained in detail by taking the method for determining the seismic performance index of a component considering the characteristics of far-field long-period seismic motion and near-fault pulse-type seismic motion as an example.

[0089] Step 1, select 100 far-field long-period ground motions, 100 near-fault pulse ground motions and 100 ordinary ground motions;

[0090] Step 2: Select an inelastic SDOF structure and determine the dynamic characteristics of the inelastic SDOF system. The SDOF is a single degree of freedom. The dynamic characteristics of the SDOF system are as follows: Under normal circumstances, the period range of the SDOF structure can be 0.5 to 10s, the damping ratio of the SDOF structure is 5%, and the hysteresis rule of the SDOF structure is selected as the BWBN restoring force model.

[0091] After solving the equation of motion, we get the bearing capacity data F(t) = αω 2 μ-(1-α)ω 2 μ z By analyzing the bearing capacity data, the bearing capacity at the maximum displacement and the peak bearing capacity are obtained. If the bearing capacity at the maximum displacement does not drop to 85% of the peak bearing capacity, the PGA of the seismic motion is adjusted to recalculate the elastic-plastic response of the SDOF system, and the acceleration amplitude PGA of each seismic motion is gradually increased from 0 to 1gal until the relative error between the bearing capacity at the maximum displacement of the structural component and 85% of the peak bearing capacity is less than or equal to 0.1%. The iteration is stopped.

[0092] Calculate the elastic-plastic displacement time-history response of the SDOF system under different earthquake motions, such as Figure 3 As shown, analysis shows that compared with ordinary ground motion, the far-field long-period ground motion action characteristics show long-duration characteristics with a large number of inelastic cycles, and the near-fault pulse ground motion shows pulse characteristics with an initial large pulse displacement.

[0093] Step 3: Based on the analysis of the special earthquake motion characteristics, a loading mode is established that can reflect the special earthquake motion characteristics and is coordinated with the traditional quasi-static loading system. The core idea is to consider the action characteristics of special earthquake motion on the basis of the traditional quasi-static loading system, so that the traditional quasi-static loading system becomes a special case in the constructed loading mode that can reflect the special earthquake motion characteristics. For example, the amplification cycle loading mode is applicable to the far-field long-period earthquake motion, in which the number of cycles is the key parameter, and when the number of cycles is 3, it is the traditional quasi-static loading system; the "pulse + traditional quasi-static loading system" loading mode is applicable to the near-fault pulse earthquake motion, in which the pulse amplitude is the key parameter, and when the pulse amplitude is zero, it is the traditional quasi-static loading system. For a specific quasi-static loading mode, when the key parameters are determined, it is equivalent to determining the specific quasi-static loading system. Different parameters under the same loading mode correspond to a series of different quasi-static loading systems.

[0094] Step 4: Analyze the relationship between key parameters and basic natural vibration period of the structure in the loading mode based on the rain flow counting method, and count the total number of pre-peak inelastic displacement cycles of the SDOF system under the special ground motion and ordinary ground motion related to the loading mode. p , the maximum displacement average value u max The corresponding relationship between the response characteristic parameters and the basic natural vibration period of the structure is analyzed. p Related to the number of cycles in the amplified cyclic loading mode, u max The ratio k of the average number of inelastic cycles of the SDOF system with a natural vibration period of 0.5 to 10 s under the action of far-field long-period ground motion and ordinary ground motion is obtained in relation to the pulse amplitude in the “pulse + traditional amplification cycle” loading mode. N =N p，S / N p，O , and the average value u of the pulse displacement response of the SDOF system with a natural vibration period of 0.5 to 10 s under the action of near-fault pulse earthquake motion max，S , and establish k N 、u max，S The mathematical relationship between the basic natural vibration period of the structure k N =f 1 (T),u max，S =f 2 (T).

[0095] Step 5: Compare and analyze the influence of key parameters in the loading mode on the seismic performance of structural components, and consider the quasi-static test and numerical simulation analysis of structural components affected by relevant indicators of the loading mode. In the quasi-static test and numerical simulation analysis, consider the influence of relevant indicators in the loading mode on the seismic performance indicators of structural components.

[0096] For example, for far-field long-period seismic motion, the focus is on analyzing the influence of the number of cycles on the seismic performance indicators of structural components; for near-fault pulse seismic motion, the focus is on analyzing the influence of the pulse amplitude on the seismic performance indicators of structural components.

[0097] In the quasi-static test, the Figure 4 The loading device used in the quasi-static test shown in the figure is used for the quasi-static loading test. 13 RC components with the same design parameters are designed, which are referred to as basic components below. The variable parameters in the test are loading paths. The loading system of the first specimen adopts the loading system recommended in the Code for Seismic Test of Buildings (JGJ T 101-2015), that is, the traditional quasi-static loading system, with 3 cycles per displacement level. The 2nd to 7th specimens adopt the amplified cyclic loading mode with 6, 9, 12, 15, 18, and 21 cycles per displacement level, respectively, considering the influence of the number of cycles on the seismic performance index of the component. The 8th to 13th specimens adopt the "pulse + traditional amplified cycle" loading mode with pulse amplitudes of 0.75, 1, 2, 3, 4, and 5 times the yield displacement, respectively, considering the influence of the pulse amplitude on the seismic performance index of the component, and on the basis of the basic component, the axial compression ratio, reinforcement ratio, and volume stirrup ratio are changed to design 3 RC components for supplementary calculation.

[0098] Finite element modeling was performed based on the quasi-static test, and quasi-static test data of RC components were selected from the PEER database for supplementary analysis, such as Figure 5 The loading mode diagrams shown in the quasi-static test taking into account the special earthquake action characteristics are as follows: (a) is the traditional loading mode diagram, (b) is the amplified cycle loading mode diagram, and (c) is the "pulse + traditional amplified cycle" loading mode diagram.

[0099] Step 6: Combine quasi-static test and numerical simulation to quantitatively analyze the influence of key parameters in loading mode on the seismic performance index of structural components, and propose seismic performance index of structural components, mainly including: bearing capacity F max , ductility coefficient μ, equivalent stiffness K at each displacement amplitude, equivalent viscous damping coefficient h e The number of cycles N and the pulse cycle amplitude δ of each level displacement amplitude s The changing relationship F max，N =f 11 (N) μ N =f 21 (N) K N =f 31 (N) h e，N =f 41 (N)

[0100] Step 7: Combine step 4 and step 6 to obtain the seismic performance index limit of the structural component under the efficient determination method of the seismic performance index of the structural component considering the influence of the special earthquake motion action characteristics. The specific method is:

[0101] Based on the relationship between the component seismic performance index obtained in step 6 and the number of cycles N of each level of displacement amplitude, N = k obtained in step 4 is converted into N ×N 传统 =f 1 (T)×N 传统 Substitute F max，N =f 11 (N), μ N =f 21 (N), K N =f 31 (N), h e，N =f 41 (N), and the relationship between the natural vibration period of the structure and the seismic performance index of the structural components considering the influence of the long-period earthquake action characteristics in the far field is obtained. max，N =F 11 (T), μ N =F 21 (T), K N =F 31 (T), h e，N =F 41 (T), where N 传统 is the number of cycles for each level of cycle amplitude in the traditional quasi-static loading system;

[0102] Based on the seismic performance index of the component obtained in step 6, the large displacement pulse cycle amplitude δ s The relationship of change is to replace the δ obtained in step 4 with s =u max，S =f 2 (T) Substitution The relationship between the natural vibration period of the structure and the seismic performance index of the structural components considering the characteristics of the near-fault pulse ground motion is obtained.

[0103] Through the above method description and further explanation of the embodiments, it can be clearly obtained that the method for determining the seismic performance index of a component taking into account the characteristics of seismic motion action of the present invention can solve the uncertainty of the use of subjective factors to determine the loading control index in the existing quasi-static test, the inability of the traditional loading system to reflect the special seismic motion characteristics, and the seismic performance index of the structural component determined based on the traditional quasi-static test loading system is not suitable for the seismic performance analysis of the structure under special seismic motion. It provides a new idea for the determination method of the seismic performance index and safety assessment of structural components under special seismic motion.

[0104] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0105] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0106] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Claims

1. A method for determining the seismic performance index of a structure considering the characteristics of earthquake action, characterized in that: Includes steps: S1. According to the method for distinguishing special types of earthquake motion, select the same number of special earthquake motions and common earthquake motions. S2. Select inelastic SDOF systems with different dynamic characteristic parameters respectively, calculate the elastic-plastic displacement response process of the SDOF system under different earthquake motions, compare and analyze the elastic-plastic displacement cyclic distribution characteristics of the SDOF system under special earthquake motions and ordinary earthquake motions, and obtain the action characteristics of special earthquake motions; S3. Based on the analysis of the characteristics of special earthquake action, determine the quasi-static loading mode that can reflect the characteristics of special earthquake action; S4. Statistically analyze the number of displacement cycles and amplitude distribution under different SDOF systems, and analyze the variation of key parameters with structural dynamic characteristics under different loading modes; S5. Through quasi-static tests and numerical simulations, comparative analysis is made on the influence of key parameters in quasi-static loading mode on the seismic performance indicators of structural components; S6. Establish the relationship between the seismic performance index of the structural components under the quasi-static loading mode and the key parameters in the quasi-static loading mode; S7. According to the basic natural vibration period of the structure in the actual project, the relationship between the key parameters in the loading mode and the structural dynamic characteristics is determined based on step S4, and then combined with step S6, the seismic performance index limit of the structural component considering the influence of the special seismic action characteristics is determined.

2. The method for determining the seismic performance index of a structure considering the characteristics of earthquake action according to claim 1, characterized in that: In step S2, the elastic-plastic displacement response process of the SDOF system under different earthquake motions is calculated, and the iterative stop point of the PGA amplitude modulation is when the structural bearing capacity drops to 85% of the peak bearing capacity. The specific steps are as follows: First, the earthquake motion is applied to the SDOF system, and the elastic-plastic displacement and bearing capacity data of the SDOF system are obtained by solving the structural motion equation: In the formula, and μ represent the normalized acceleration, velocity and displacement of the SDOF system respectively; ξ is the damping ratio of the SDOF system; ω is the natural frequency of the SDOF system; α is the stiffness ratio before and after the structural yield, and its value is between 0 and 1; is the ground acceleration; δ y is the yield displacement of the structure; where it involves the hysteresis displacement μ defined by the first-order differential equation z , as shown below: In the formula, is the hysteresis velocity, A, β, γ and n are the shape parameters of the hysteresis curve; ν, η and h(μ z ) respectively describe the strength degradation, stiffness degradation and pinching effect, and are obtained by the following formula: v=1+δ $ e (3) n=1+d & e (4) in: ζ1=ξ3[1-exp(-pε)] (6) ζ2=(ψ+δ7ε)(λ+ζ1) (7) In the formula, δ η and δ v are strength and stiffness degradation parameters respectively; ξ s ,ψ,δ ψ , λ, q and p are pinching effect parameters, where ξ s Controls the total slip, ψ controls the pinching amplitude, δ ψ is the pinching rate, λ is the interaction coefficient between pinching severity and pinching rate, q controls the starting position of pinching, and p is the pinching slope; is a sign function related to speed, when hour, are 1, 0 and -1 respectively; ε is the accumulated hysteresis energy dissipation in the time series T, which is defined by the following formula: The high-order differential equation of formula (1) is transformed into a first-order differential equation system, as shown in formula (10). The initial conditions are y1 = 0, y2 = 0, y3 = 0, y4 = 0. In this way, the fourth-order Runge-Kutta method can be used to solve the motion equation of the SDOF system with the bearing capacity model of BWBN. After solving the equation of motion, we get the bearing capacity data F(t) = αω 2 μ-(1-α)ω 2 μ z By analyzing the bearing capacity data, the bearing capacity at the maximum displacement and the peak bearing capacity are obtained. If the bearing capacity at the maximum displacement does not drop to 85% of the peak bearing capacity, the PGA of the seismic motion is adjusted to recalculate the elastic-plastic response of the SDOF system, and the acceleration amplitude PGA of each seismic motion is gradually increased from 0 to 1gal until the relative error between the bearing capacity at the maximum displacement of the structural component and 85% of the peak bearing capacity is less than or equal to 0.1%. The iteration is stopped.

3. The method for determining the structural seismic performance index considering the seismic action characteristics according to claim 1 is characterized in that: In step S2, the cyclic distribution characteristics of the elastic-plastic displacement of the SDOF system under the action of special earthquake motion and ordinary earthquake motion are compared and analyzed. The action characteristics of the special earthquake motion can be obtained by comparing the cycle number and pulse amplitude characteristics in the cyclic distribution of the elastic-plastic displacement under different SDOF systems.

4. The method for determining the seismic performance index of a structure considering the characteristics of earthquake action according to claim 1, characterized in that: The quasi-static loading mode of the special earthquake action characteristics in step S3 is: based on the analysis of the special earthquake action characteristics, a loading mode that can reflect the special earthquake action characteristics and is coordinated with the traditional quasi-static loading system is established, that is, a loading mode that combines key parameters with the traditional quasi-static loading system is formed.

5. The method for determining the structural seismic performance index considering the seismic action characteristics according to claim 4 is characterized in that: The quasi-static loading mode of the special earthquake action characteristics in step S3, when the key parameters are determined, is equivalent to determining a specific quasi-static loading system. Different key parameters under the same loading mode correspond to a series of different quasi-static loading systems.

6. The method for determining the structural seismic performance index considering the seismic action characteristics according to claim 1 is characterized in that: The specific steps of analyzing the variation of key parameters with structural dynamic characteristics in different loading modes in step S4 are as follows: Different loading modes include: traditional loading mode and quasi-static loading mode. The relationship between key parameters and basic natural vibration period of the structure in different loading modes is analyzed based on the rain flow counting method, and the average number of pre-peak inelastic displacement cycles N of the SDOF system under special ground motion and ordinary ground motion in different loading modes is calculated. p , the maximum displacement average value u max Equal response characteristic parameters, and analyze the corresponding relationship between their structural dynamic characteristics, where N p Related to the number of cycles in the amplified cyclic loading mode, u max The ratio k of the average number of inelastic cycles of the SDOF system with a natural vibration period of 0.5 to 10 s under special ground motion and ordinary ground motion is obtained in relation to the pulse amplitude in the "pulse + traditional amplification cycle" loading mode. Z =N p,S / N p,O , and the average value u of the pulse displacement response of the SDOF system with a natural vibration period of 0.5 to 10 s under special earthquake motion max,S , and establish k Z 、u _`a,b The relationship between k and the basic natural vibration period of the structure is: Z =f1(T),u max,S =f2(T).

7. The method for determining the seismic performance index of a structure considering the characteristics of earthquake action according to claim 1, characterized in that: The specific steps of establishing the relationship between the seismic performance index of the structural component under the quasi-static loading mode and the key parameters in the quasi-static loading mode in step S6 are: Through quasi-static tests and numerical simulations, the influence of key parameters in quasi-static loading mode on the seismic performance indicators of structural components is quantitatively analyzed. It is concluded that the seismic performance indicators of structural components mainly include: bearing capacity F _`a , ductility coefficient μ, equivalent stiffness K at each displacement amplitude, equivalent viscous damping coefficient h g .

8. The method for determining the seismic performance index of a structure considering the characteristics of earthquake action according to claim 1, characterized in that: In step S7, based on the relationship between the key parameters in the loading mode and the structural dynamic characteristics determined in step S4, and in combination with step S6, the specific steps for determining the seismic performance index limit of the structural component considering the influence of the special earthquake action characteristics are as follows: N=k obtained in step S4 Z ×N 传统 =f1(T)×N 传统 Substitute F _`a,Z =f 11 (N), μ Z =f 21 (N), K Z =f G1 (N), h g,Z =f T1 (N), and the relationship between the natural vibration period of the structure and the seismic performance index of the structural components considering the influence of the long-period earthquake action characteristics in the far field is obtained: F _`a,Z =F 11 (T), μ Z =F 21 (T), K Z =F G1 (T), h g,Z =F T1 (T), where N 传统 is the number of cycles for each level of cycle amplitude in the traditional quasi-static loading system; Based on the seismic performance index of the component obtained in step S6, the large displacement pulse cycle amplitude δ s The changed relationship is to replace the δ3 obtained in step S4 with u max,S =f2(T)Substitute The relationship between the natural vibration period of the structure and the seismic performance index of the structural components considering the influence of the characteristics of the near-fault pulse ground motion is obtained:

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