Anti-seismic simulation method for existing building by considering real damage state

Abstract

Disclosed in the present invention is an anti-seismic simulation method for an existing building by considering a real damage state. The method comprises: determining a quantified component damage index on the basis of an observed component damage state; determining a material damage index of a damaged component on the basis of the component damage index; determining key parameters of a constitutive law for a damaged material on the basis of the material damage index; establishing a finite element model of a damaged building on the basis of the constitutive law for the material of the damaged component; and assessing the seismic risk and anti-seismic performance of the damaged building on the basis of the finite element model. In the present invention, a constitutive law for a damaged material is incorporated into a fiber model in OpenSEES, so that rapid modeling of a damaged building can be realized, thereby effectively reproducing the real damage of an existing building; and by using a seismic vulnerability analysis method, rapid assessment of the seismic risk and anti-seismic capability of the existing building can be realized, thereby further providing support for formulating reasonable reinforcement and reconstruction strategies by related departments.

Description

Seismic simulation method for existing building considering real damage state TECHNICAL FIELD

[0001] The application belongs to the technical field of building seismic simulation, and particularly relates to a seismic simulation method for existing building considering real damage state. BACKGROUND

[0002] During the service period of urban buildings, natural or man-made factors such as earthquakes, concrete carbonization and steel corrosion may cause problems such as load capacity reduction and function reduction. If these buildings are to be used, the residual performance of the buildings must be evaluated, and reasonable reinforcement and reconstruction strategies must be developed to restore and improve the original seismic performance of the buildings. In this case, the seismic numerical simulation technology of damaged buildings is used for rapid performance evaluation of existing buildings due to its significant efficiency, convenience and accuracy.

[0003] The pre-damage method and the component performance reduction method are two main methods for simulating the seismic performance of damaged buildings. Taking a building damaged by an earthquake as an example, the pre-damage method simulates the damage of the structure by applying a real seismic record to the numerical model of the intact building for nonlinear time history analysis, and then evaluates the seismic capacity of the building. The commonly used sequence earthquake analysis and post-earthquake pushover analysis belong to the pre-damage method. However, the structural damage determined by the numerical results of nonlinear time history analysis may not match the actual damage state. The existing numerical simulation results show that in nonlinear time history analysis, the column end plastic hinge failure mode may be incorrectly predicted as a beam end plastic hinge failure mode. The component performance reduction method reduces the macroscopic mechanical properties of components according to the observed component damage, and then assigns the reduced mechanical properties to the elements of the simulated structure components to achieve seismic simulation of damaged buildings. However, this method is a macroscopic simulation method that fails to describe the real damage state of materials, and may incorrectly estimate the seismic performance of damaged buildings.

[0004] In summary, the traditional numerical simulation technology of damaged buildings cannot consider the actual damage of buildings from the material and component level, and thus cannot accurately evaluate the seismic performance of damaged buildings. Therefore, a numerical simulation method is needed that can reverse the damaged material properties according to the observed structural damage, in order to accurately and quickly evaluate the seismic performance of existing buildings. SUMMARY

[0005] The purpose of the present application is to provide a seismic simulation method for existing buildings considering real damage state, which can quickly establish a numerical model of a damaged building according to the actual observed structural and component damage, and then evaluate the seismic risk and seismic capacity of the building, which helps relevant departments to develop reasonable reinforcement and reconstruction strategies.

[0006] Technical solution: To achieve the above object, the application provides an existing building anti-seismic simulation method considering real damage state, comprising the following steps:

[0007] S1: determining a quantified component damage index according to the observed component damage state;

[0008] S2: determining a material damage index of the damaged component according to the component damage index;

[0009] S3: determining key parameters of the damaged material constitutive according to the material damage index;

[0010] S4: establishing a finite element model of the damaged building based on the material constitutive of the damaged component;

[0011] S5: performing seismic risk and anti-seismic performance evaluation of the damaged building according to the finite element model.

[0012] Further, the component damage index in the step S1 is quantitatively represented by a Park-Ang damage index DI.

[0013] Further, the material damage index of the damaged component is determined by using a damage distribution model in the step S2; the cross section of the reinforced concrete component is divided into three regions of protective layer concrete, core zone concrete and steel bar, and the damage distribution model represents the mapping relationship between the material damage indexes of the three regions and the component damage index DI, so as to determine the material damage index of the damaged component.

[0014] Further, the mapping relationship between the protective layer concrete material damage index D c and the DI, the mapping relationship between the core zone concrete material damage index D cc and the DI, and the mapping relationship between the steel bar material damage index D s and the DI are respectively shown in formulas (1), (2) and (3),

[0015] Further, the damaged material in the step S3 comprises three materials of damaged protective layer concrete, damaged core zone concrete and damaged steel bar.

[0016] Further, the constitutive of the damaged protective layer concrete in the step S3 is simulated by using a Kent-Scott-Park model, and the skeleton curve of the model is defined by three parameters of peak compressive strain ε cd , peak compressive stress f cd and ultimate compressive strain ε cu , and the calculation formulas are respectively

[0017] wherein, ε c and f crespectively represent the peak compressive strain and peak compressive stress of the concrete without damage to the protective layer; ε cd and f cd respectively represent the peak compressive strain and peak compressive stress of the concrete with damage to the protective layer; Z represents the strain softening slope coefficient.

[0018] Further, the constitutive relation of the damaged core concrete in step S3 is simulated by the Mander model, and the skeleton curve of the model is defined by four parameters of peak compressive strain ε ccd , peak compressive stress f ccd , ultimate compressive strain ε ccu and elastic modulus E ccd , and the calculation formulas are as follows:

[0019] wherein, ε cc and f cc respectively represent the peak compressive strain and peak compressive stress of the concrete without damage to the protective layer; ε ccd and f ccd respectively represent the peak compressive strain and peak compressive stress of the concrete without damage to the protective layer; r represents the shape coefficient of the skeleton curve; E c represents the elastic modulus of the concrete without damage to the protective layer; E sec =f cc / ε cc represents the secant modulus of the concrete without damage to the protective layer at the peak stress; f yv represents the yield strength of the stirrup; ε su represents the fracture strain of the stirrup; and ρ v represents the volumetric stirrup ratio of the stirrup.

[0020] Further, the constitutive relation of the damaged steel bar in step S3 is simulated by a three-fold line model, and the skeleton curve of the model is determined by three data points in positive and negative directions; the mechanical behavior of the steel bar is symmetric in positive and negative directions, so the values of the key points in positive and negative directions are the same; the three data points (ε1, σ1), (ε2, σ2) and (ε3, σ3) are determined as follows:

[0021] The stress σ1 and strain ε1 of the first data point are calculated as follows: y (13)

[0022] wherein, E s and f y respectively represent the elastic modulus and yield strength of the steel bar.

[0023] The stress σ2 and strain ε2 of the second data point are determined according to the damage index D s of the steel bar, and are calculated as follows:

[0024] wherein ε y and b represent the yield strain and strain hardening rate of the reinforcement, respectively;

[0025] The stress σ3 and strain ε3 of the third data point are calculated as follows, respectively σ3 = f u (17)

[0026] wherein f u represents the ultimate stress of the reinforcement.

[0027] Further, the finite element model of the damaged building is established in step S4 using the OpenSEES platform: since the main damage of the frame beam and the frame column under the action of the earthquake is concentrated in the plastic hinge section of the beam end, a plastic hinge beam-column element based on the fiber section is used to simulate the structural member; the plastic hinge beam-column element based on the fiber section is a fiber beam-column element based on force, and the plastic hinge length L p , L p is defined at both ends of the element when the element is used. p = 0.08L + 0.022f y d l (N, mm) (19)

[0028] wherein L represents the length of the equivalent cantilever member of the structural member; d l represents the diameter of the reinforcement.

[0029] The control section of the plastic hinge section at both ends of the beam-column element is a fiber section composed of damaged material, and the control section of the middle section is a fiber section composed of undamaged material; the constitutive relation of the damaged and undamaged protective layer concrete is simulated by using the Concrete02 model based on the Kent-Scott-Park model skeleton curve, and ε cd , f cd and ε cu are input into the call command of the Concrete02 model to simulate the constitutive relation of the damaged protective layer concrete; ε c , f c and ε cu are input into the call command of the Concrete02 model to simulate the constitutive relation of the undamaged protective layer concrete; the constitutive relation of the damaged and undamaged core zone concrete is simulated by using the Concrete04 model based on the Mander model skeleton curve, and E cd , ε ccd , f ccd and ε ccuThe command to invoke the Concrete04 model can simulate the constitutive model of the damaged core concrete, and E c ε cc f cc and ε ccu The Concrete04 model call command simulates the constitutive model of the undamaged core concrete; damaged and undamaged reinforcing bars are simulated using the Hysteretic and Steel02 models respectively. Inputting (ε1,σ1), (ε2,σ2), and (ε3,σ3) into the Hysteretic model call command simulates the constitutive model of the damaged reinforcing bars. y E s The command to call the Steel02 model by inputting b can simulate the constitutive model of undamaged steel reinforcement.

[0030] Furthermore, in step S5, the seismic vulnerability analysis method is used to assess the seismic risk and seismic performance of the damaged building. Seismic vulnerability is described as the cumulative probability that a structure will exceed a certain limit state under a specific seismic ground motion intensity IM. The probabilistic seismic vulnerability model is specifically represented as the convolution of the demand model and the capacity model, as shown in the following formula.

[0031] Wherein, EDP represents the engineering requirements parameters of the structure; LS i S represents the EDP threshold corresponding to a certain limiting state. d|IM and β D|IM Here, β represents the median and standard deviation of the structural seismic demand under a given IM; C β represents the degree of dispersion of the limiting state, which is taken as 0.3; M The standard deviation representing the model uncertainty is taken as 0.2; Φ[·] represents the cumulative normal distribution function;

[0032] Median earthquake demand S d|IM The relationship between S and the seismic intensity parameter IM follows a power-law regression, as shown below. d|IM =a(IM) b (twenty one)

[0033] Performing a logarithmic transformation on formula (21), we can obtain ln S d|IM =ln a+bln IM (22)

[0034] Where a and b are regression coefficients; the logarithmic standard deviation β of earthquake demand D|IM The calculation is as follows

[0035] Wherein, N is the total number of nonlinear dynamic time history analysis; i represents the i th nonlinear dynamic time history analysis; the data points for regression analysis are obtained by the incremental dynamic analysis (IDA) method and the cloud map method.

[0036] Beneficial effects: Compared with the prior art, the present application can intuitively reveal the damage degree of the material by converting the actual observed component damage state into a quantitative material damage index through a damage distribution model for existing buildings, and is more scientific and reasonable than the existing pre-damage method and component performance reduction method; a damaged material constitutive determination method based on the material damage index is proposed, the constitutive of the damaged material is assigned to the fiber model of OpenSEES, the rapid modeling of the damaged building can be realized, and the real damage of the existing building is effectively restored; combined with the seismic vulnerability analysis method, the seismic risk and seismic capacity of the existing building can be quickly evaluated, and further support is provided for the relevant departments to make reasonable reinforcement and reconstruction strategies. BRIEF DESCRIPTION OF DRAWINGS

[0037] Fig. 1 is a flowchart of the method of the present application;

[0038] Fig. 2 is a schematic diagram of the damaged material constitutive curve;

[0039] Fig. 3 is a schematic diagram of the OpenSEES finite element modeling of the damaged building;

[0040] Fig. 4 is a schematic diagram of the material model used for finite element modeling;

[0041] Fig. 5 is a schematic diagram of a two-dimensional 5-story 4-span reinforced concrete frame structure in the embodiment;

[0042] Fig. 6 is an IDA curve diagram of the intact structure and the damaged structure in the embodiment;

[0043] Fig. 7 is a diagram of the relationship between the engineering demand parameter and the ground motion intensity parameter of the intact structure and the damaged structure in the embodiment;

[0044] Fig. 8 is a vulnerability result diagram of the intact structure and the damaged structure in the embodiment. DETAILED DESCRIPTION

[0045] The present application will be further illustrated below in conjunction with the drawings and specific embodiments, and it should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application, and various equivalent modifications of the present application made by those skilled in the art after reading the present application all fall within the scope defined by the appended claims.

[0046] The present application provides an existing building seismic simulation method considering real damage state, as shown in Fig. 1, comprising the following steps:

[0047] S1: determining a quantitative component damage index according to the observed component damage state:

[0048] The component damage index is quantitatively represented by the Park-Ang damage index DI, and Table 1 summarizes the DI range corresponding to the component damage state:

[0049] Table 1 DI range corresponding to different component damage states

[0050] For ease of practical use, the damage index DI of the component in different damage states can be represented by the median value of the corresponding damage index range.

[0051] S2: Determine the material damage index of the damaged component according to the component damage index:

[0052] The material damage index of the damaged component is determined using a damage distribution model; the cross section of the reinforced concrete component is divided into three regions: protective layer concrete, core zone concrete, and steel bar, and the damage distribution model represents the mapping relationship between the material damage index of the three regions and the component damage index DI, thereby determining the material damage index of the damaged component.

[0053] The mapping relationship between the material damage index D c of the protective layer concrete and the DI, the material damage index D cc of the core zone concrete and the DI, and the material damage index D s of the steel bar and the DI are respectively shown in formulas (1) to (3),

[0054] S3: Determine the key parameters of the damaged material constitutive according to the material damage index:

[0055] The damaged material includes damaged protective layer concrete, damaged core zone concrete, and damaged steel bar. The determination schematic diagram of the damaged protective layer concrete, damaged core zone concrete, and damaged steel bar constitutive curve is respectively shown in (a), (b), and (c) of FIG. 2:

[0056] The constitutive of the damaged protective layer concrete is simulated by the Kent-Scott-Park model, and the skeleton curve of the model is defined by three parameters: peak compressive strain ε cd , peak compressive stress f cd , and ultimate compressive strain ε cu , and the calculation formulas are respectively

[0057] wherein, ε c and f c represent the peak compressive strain and peak compressive stress of the undamaged protective layer concrete, respectively; ε cd and f cdrespectively represent the peak compressive strain and peak compressive stress of the damaged core concrete; Z represents the strain-softening slope coefficient.

[0058] The constitutive model of the damaged core concrete is simulated by Mander model, whose skeleton curve is defined by four parameters of peak compressive strain ε ccd , peak compressive stress f ccd , ultimate compressive strain ε ccu and elastic modulus E ccd , whose calculation formula is

[0059] wherein, ε cc and f cc respectively represent the peak compressive strain and peak compressive stress of the undamaged core concrete; ε ccd and f ccd respectively represent the peak compressive strain and peak compressive stress of the undamaged core concrete; r represents the skeleton curve shape coefficient; E c represents the elastic modulus of the undamaged core concrete; E sec =f cc / ε cc represents the secant modulus of the undamaged core concrete at the peak stress; f yv represents the yield strength of the stirrup; ε su represents the fracture strain of the stirrup; ρ v represents the volumetric stirrup ratio of the stirrup.

[0060] The constitutive model of the damaged steel bar is simulated by three-line model, whose skeleton curve is determined by three data points in positive and negative directions; the mechanical behavior of the steel bar is symmetrical in positive and negative directions, so the values of the key points in positive and negative directions are the same; the three data points (ε1, σ1), (ε2, σ2) and (ε3, σ3) are determined as follows:

[0061] The stress σ1 and strain ε1 of the first data point are calculated as follows respectively σ1=0.1f y (13)

[0062] wherein, E s and f y respectively represent the elastic modulus and yield strength of the steel bar;

[0063] The stress σ2 and strain ε2 of the second data point are determined according to the damage index D s of the steel bar, and are calculated as follows

[0064] wherein, ε y and b respectively represent the yield strain and strain hardening rate of the steel bar;

[0065] The stress σ3 and strain ε3 of the third data point are calculated as follows, respectively σ3 = f u (17)

[0066] wherein f u represents the ultimate stress of the steel bar.

[0067] S4: Establishing the finite element model of the damaged building based on the material constitutive of the damaged component:

[0068] As shown in FIG. 3, the finite element model of the damaged building is established by using the OpenSEES platform: since the main damage of the frame beam and the frame column under the action of the earthquake is concentrated in the plastic hinge section of the beam end, the plastic hinge beam-column element based on the fiber section is used to simulate the structural component; the plastic hinge beam-column element based on the fiber section is a fiber beam-column element based on force, and the plastic hinge length L p at both ends needs to be defined when using the element p L p = 0.08L + 0.022f y d l (N, mm) (19)

[0069] wherein L represents the length of the equivalent cantilever component of the structural component; d l represents the diameter of the steel bar.

[0070] The control section of the plastic hinge section at both ends of the beam-column element is the fiber section composed of damaged material, and the control section of the middle section is the fiber section composed of undamaged material; the constitutive of the damaged and undamaged protective layer concrete is simulated by using the Concrete02 model based on the Kent-Scott-Park model skeleton curve, and ε cd , f cd and ε cu are input into the calling command of the Concrete02 model to simulate the constitutive of the damaged protective layer concrete, and ε c , f c and ε cu are input into the calling command of the Concrete02 model to simulate the constitutive of the undamaged protective layer concrete; the constitutive of the damaged and undamaged core area concrete is simulated by using the Concrete04 model based on the Mander model skeleton curve, and E cd , ε ccd , f ccd and ε ccu are input into the calling command of the Concrete04 model to simulate the constitutive of the damaged core area concrete, and E c , εcc , f cc and ε ccu The call command of Concrete04 model inputting (ε1, σ1), (ε2, σ2) and (ε3, σ3) can simulate the constitutive of undamaged core concrete; the call command of Hysteretic model inputting (ε1, σ1), (ε2, σ2) and (ε3, σ3) can simulate the constitutive of damaged steel bar; the call command of Steel02 model inputting f y , E s and b can simulate the constitutive of undamaged steel bar. The corresponding material models are shown in Fig. 4.

[0071] To ensure the accuracy and efficiency of the numerical model, it is recommended that the number of fibers of the protective layer concrete is 16 × 1 or more, and the number of fibers of the core concrete is 14 × 14 or more.

[0072] S5: According to the finite element model, the seismic risk and seismic performance of the damaged building are rapidly evaluated:

[0073] The seismic risk and seismic performance of the damaged building are evaluated by using the seismic vulnerability analysis method; the seismic vulnerability is described as the cumulative probability of the structure exceeding a certain limit state under a certain seismic intensity IM, and the probabilistic seismic vulnerability model is specifically expressed as the convolution of the demand model and the capacity model, as follows

[0074] where EDP is the engineering demand parameter of the structure; LS i represents the EDP threshold value corresponding to a certain limit state; S d|IM and β D|IM are the median value and standard deviation of the seismic demand of the structure under a given IM, respectively; β C represents the dispersion degree of the limit state, which is taken as 0.3; β M represents the standard deviation of the model uncertainty, which is taken as 0.2; Φ[·] represents the cumulative normal distribution function;

[0075] The median value S d|IM of the seismic demand and the seismic intensity parameter IM obey a power exponential regression relationship, which is expressed as follows S d|IM = a(IM) b (21)

[0076] The logarithmic transformation of formula (21) can be obtained ln S d|IM = ln a + b ln IM (22)

[0077] Wherein, a and b are regression coefficients; the logarithmic standard deviation of seismic demand β D|IM is calculated as follows

[0078] Wherein, N is the total number of nonlinear dynamic time history analysis; i represents the i th nonlinear dynamic time history analysis; the data points for regression analysis are obtained by the incremental dynamic analysis (IDA) method and the cloud method.

[0079] In order to verify the effectiveness of the method of the application, the above scheme is applied in the embodiment, specifically as follows:

[0080] The embodiment provides an existing building seismic simulation method considering real damage state, referring to Fig. 1, comprising the following steps:

[0081] Step one: determining the quantified component damage index according to the observed component damage state

[0082] The simulation object of the embodiment is a designed two-dimensional 5-layer 4-span reinforced concrete frame structure, as shown in Fig. 5, the bottom layer is 4.5 m high, and the remaining floors are 3.6 m high, the beam and column section sizes are 250 mm x 500 mm and 500 mm x 500 mm respectively, and the reinforcement details are shown in Fig. 5. The design uniform dead load of the floor and roof is 5.0 kN / m 2 and 7.0 kN / m 2 , respectively, and the floor uniform live load and roof snow load are both 2.0 kN / m 2 . It is assumed that the prototype building is located in Nanjing, China, the seismic fortification intensity of the region is 7 degrees, the design earthquake grouping is the first group, the II type site, the design basic earthquake acceleration is 0.1g, and the soil layer equivalent shear wave velocity is between 250-500 m / s. The concrete strength grade is C40, the longitudinal reinforcement and stirrup type are both HRB400, and the concrete cover thickness of the frame beam and frame column is both 25 mm. The material parameters of the undamaged cover concrete, core concrete and steel bars are shown in Tables 2, 3 and 4, respectively, wherein the restraint effect of the stirrup on the core concrete is considered by the Mander model.

[0083] Table 2 Material parameters of undamaged cover concrete

[0084] Table 3 Material parameters of undamaged core concrete

[0085] Table 4 Material parameters of undamaged steel bars

[0086] The damage state of the damaged structure is moderate damage, and the component damage state is consistent with the structure damage state. Referring to Table 1 in the application, the Park-Ang damage index DI of the damaged structure component can be taken as 0.325.

[0087] Step two: Determine the material damage index of the damaged component according to the component damage index

[0088] Substitute DI into the formulas (1), (2) and (3) of the present application, the fiber damage indexes of the damaged protective layer concrete, core zone concrete and steel bar are D c = 0.886, D cc = 0.571 and D s = 0.755, respectively.

[0089] Step three: Determine the key parameters of the damaged material constitutive according to the material damage index

[0090] Substitute D c into the formulas (4) and (5), D cc into the formulas (8) and (9), and D s into the formulas (15) and (16), the key parameters of the damaged protective layer concrete, core zone concrete and steel bar constitutive can be obtained, which are shown in Tables 5, 6 and 7, respectively.

[0091] Table 5 Material parameters of damaged protective layer concrete

[0092] Table 6 Material parameters of damaged core zone concrete

[0093] Table 7 Material parameters of damaged steel bar

[0094] Step four: Establish the finite element model of the damaged building based on the material constitutive of the damaged component

[0095] The numerical model of the damaged building is established on the OpenSEES platform, as shown in FIG. 3. The frame beam and frame column are simulated by the concentrated plastic hinge element based on the fiber section. The plastic hinge zone at both ends of the element is simulated by the damaged material constitutive, and the middle section is simulated by the undamaged material constitutive. The constitutive of the damaged and undamaged protective layer concrete is simulated by the Concrete02 model, the constitutive of the damaged and undamaged core zone concrete is simulated by the Concrete04 model, and the damaged and undamaged steel bars are simulated by the Hysteretic and Steel02 models, respectively. The material parameters in Tables 2 to 7 are input into the calling command of the corresponding material model to simulate the damaged and undamaged materials. The plastic hinge length L p is calculated according to the formula (19), wherein the length of the equivalent cantilever component is determined according to the position of the inflection point of the component. The plastic hinge lengths at both ends of the frame beam and frame column are summarized in Table 8.

[0096] Table 8 Plastic hinge length of frame component

[0097] Step five: Perform the rapid seismic risk and seismic performance assessment of the damaged building.

[0098] IDA method is used to analyze the seismic fragility of the damaged building, and the results are compared with the intact building. The input ground motion records are selected from the 22 far-field ground motions recommended by the ATC-63 project, and the spectral acceleration S a as the intensity measure IM, and the maximum inter-story drift ratio IDR as the engineering demand parameter EDP of the structure. In the IDA method, the selected IM is gradually increased from 0 with an interval of 0.05g until the structure is completely destroyed, in order to obtain the probabilistic seismic demand of the structure. The limit state of the structure is divided into four limit states according to the American FEMA-356, namely normal use (OP), immediate occupancy (IO), life safety (LS) and collapse prevention (CP), and the corresponding IDR threshold is determined according to the American "Hazus Seismic Simulation Technical Manual" (referred to as "Hazus Manual"). According to the provisions of the "Hazus Manual", the designed 5-storey 4-span reinforced concrete frame conforms to the medium specification seismic design level, and the structure type belongs to C1M, and the corresponding IDR threshold is summarized in Table 9.

[0099] Table 9 IDR threshold of four limit states

[0100] The IDA curves of the intact structure and the damaged structure are shown in Figs. 6(a) and (b) respectively, in which the 16%, 50% and 84% percentile curves are used to statistically represent the median value and dispersion of all IDA curves. The S a The quantitative results are summarized in Table 10. Taking the 50% percentile curve as an example, when using the maximum inter-story drift ratio IDR as the EDP, the S a of the intact structure and the damaged structure to reach the LS performance level are 0.403g and 0.169g respectively, which shows that damage can seriously reduce the ability of the structure to resist earthquakes, which is consistent with general cognition.

[0101] Table 10 S a required by the four performance levels in the percentile curve (g)

[0102] The IDA results of the intact structure and the damaged structure are subjected to logarithmic linear regression to establish the representative relationship between S a and IDR, as shown in Fig. 7, from which the parameters (lna, b and β D|IM ) that determine the seismic fragility of the structure can be obtained. The R 2 of the logarithmic linear regression is greater than 0.8, indicating that S aIt is very suitable to establish probabilistic seismic model as IM to evaluate the effect of damage on structures.

[0103] To analyze the effect of damage on the seismic vulnerability of RC structures, the comparison of the seismic vulnerability curves of the intact structure (USM) and the damaged structure (DSM) and the difference of the exceeding probability of the four limit states are plotted, as shown in Fig. 8. In Fig. 8(a), the solid line represents the intact structure, and the dashed line represents the damaged structure. It can be seen that the damage will make the seismic vulnerability curve of the structure move to the left, reflecting the significant increase in the probability of exceeding the same limit state. The median S a The median S

[0104] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. Those skilled in the art can obviously make various modifications to these embodiments, and apply the general principles described herein to other embodiments without having to go through creative labor. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art within the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A method for simulating seismic resistance of an existing building considering a real damage state, characterized by, The method comprises the following steps: S1: determining a quantified component damage index according to an observed component damage state; S2: determining a material damage index of the damaged component according to the component damage index; S3: determining key parameters of a damaged material constitutive model according to the material damage index; S4: establishing a finite element model of the damaged building based on the material constitutive model of the damaged component; S5: performing seismic risk and seismic performance evaluation of the damaged building according to the finite element model.

2. The method of claim 1, wherein the method is characterized by, The component damage index in the step S1 is quantitatively represented by a Park-Ang damage index DI. 3.The method of claim 1, wherein, The material damage index of the damaged component is determined by using a damage distribution model in the step S2; a cross section of a reinforced concrete component is divided into three regions of a protective layer concrete, a core zone concrete and a steel bar, and the damage distribution model represents a mapping relationship between the material damage indexes of the three regions and the component damage index DI, so as to determine the material damage index of the damaged component.

4. The method of claim 3, wherein the method is characterized by, The damage index D of the protective layer concrete material in step S2 c The mapping relationship between the damage index D of the core concrete material and the DI cc The mapping relationship between the damage index D of the steel material and the DI s The mapping relationships between the damage index D and the DI are as follows:

5. The method of claim 1, wherein the method is characterized by: The damaged material in the step S3 includes three materials of damaged protective layer concrete, damaged core zone concrete and damaged steel bar.

6. The method of claim 5, wherein the method further comprises: The constitutive of the damaged protective layer concrete in step S3 is simulated by using Kent-Scott-Park model, and the skeleton curve of the model is defined by peak compressive strain ε cd , peak compressive stress f cd , and ultimate compressive strain ε cu Three parameters, and the calculation formulas are as follows: where ε c and f c represent the peak compressive strain and peak compressive stress of the concrete without the protective layer, respectively; ε cd and f cd represent the peak compressive strain and peak compressive stress of the concrete with the damaged protective layer, respectively; and Z represents the strain-softening slope coefficient.

7. The method of claim 5, wherein the method further comprises: The constitutive of the damaged core concrete in step S3 is simulated by Mander model, and the skeleton curve of the model is defined by four parameters of peak compressive strain ε ccd , peak compressive stress f ccd , ultimate compressive strain ε ccu and elastic modulus E ccd , and the calculation formulas are as follows: wherein ε cc and f cc represent the peak compressive strain and the peak compressive stress of the non-damaged core zone concrete, respectively; ε ccd and f ccd represent the peak compressive strain and the peak compressive stress of the non-damaged core zone concrete, respectively; r represents a skeleton curve shape factor; E c represents the elastic modulus of the non-damaged core zone concrete; E sec = f cc / ε cc represents the secant modulus of the non-damaged core zone concrete at the peak stress; f yv represents the yield strength of the stirrup; ε su represents the fracture strain of the stirrup; and p v represents the volumetric stirrup ratio of the stirrup. 8.The method of claim 5, wherein the method further comprises: The constitutive model of the damaged steel bar in the step S3 is simulated by using a three-fold line model, and a skeleton curve of the model is determined by three data points in positive and negative directions; the mechanical behavior of the steel bar is symmetric in positive and negative directions, so the values of the key points in positive and negative directions are the same; the three data points (ε1, σ1), (ε2, σ2) and (ε3, σ3) are determined as follows: The stress σ1 and the strain ε1 of the first data point are calculated as follows: σ1 = 0.1f y , wherein E s and f y respectively represent the elastic modulus and the yield strength of the reinforcement. The stress σ2 and strain ε2 of the second data point are determined in accordance with the steel material damage index D s Determined, calculated as follows: where ε y and b represent the yield strain and strain hardening rate of the reinforcement, respectively; The stress σ3 and the strain ε3 of the third data point are calculated as follows: σ3 = f u , where f u represents the ultimate stress of the reinforcement. 9.The method of claim 1, wherein, The step S4 uses the OpenSEES platform to establish a finite element model of the damaged building: a plastic hinge beam column element based on a fiber section is used to simulate the structural member; the plastic hinge beam column element based on a fiber section is a fiber beam column element based on force, and the use of the element requires definition of the plastic hinge length L p , L p is calculated as follows: L p = 0.08L + 0.022f y d l (N, mm), wherein L represents the length of the structural member equivalent to a cantilever member; d l represents the diameter of the reinforcing bar; The control section of the plastic hinge region at both ends of the beam column element is a fiber section composed of damaged materials, and the control section of the middle section is a fiber section composed of undamaged materials; the constitutive models of the damaged and undamaged protective layer concretes are simulated by using a Concrete02 model based on a skeleton curve of a Kent-Scott-Park model, the constitutive models of the damaged and undamaged core zone concretes are simulated by using a Concrete04 model based on a skeleton curve of a Mander model, and the damaged and undamaged steel bars are simulated by using a Hysteretic model and a Steel02 model respectively. 10.The method of claim 1, wherein, The step S5 adopts a seismic vulnerability analysis method to evaluate the seismic risk and seismic performance of the damaged building; the seismic vulnerability is described as the cumulative probability of a structure exceeding a certain limit state under a certain seismic intensity IM, and the probabilistic seismic vulnerability model is specifically expressed as the convolution of a demand model and a capacity model, and the formula is as follows: where EDP is the engineering demand parameter of the structure; LS i denotes the EDP threshold value corresponding to a limit state; S d|IM and β D|IM are the median value and the standard deviation of the seismic demand of the structure under a given IM, respectively; β C denotes the dispersion degree of the limit state; β M denotes the standard deviation of the model uncertainty; Φ[·] denotes the cumulative normal distribution function; Seismic demand median value S d|IM and the seismic intensity parameter IM obey a power exponential regression relationship, expressed as follows: S d|IM = a(IM) b , Taking logarithm of the above equation, we have lnS d|IM = ln a + b ln IM, where a and b are regression coefficients; the logarithmic standard deviation of the seismic demand β D|IM is calculated as follows: Wherein, N is the total number of nonlinear dynamic time history analysis; i represents the i th nonlinear dynamic time history analysis; the data points used for regression analysis are obtained by an incremental dynamic analysis (IDA) method and a cloud map method.

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