Reinforced concrete pier damage evaluation method, device, equipment and storage medium

Abstract

The present application relates to the field of bridge health detection, and in particular to a reinforced concrete pier damage evaluation method, device, equipment and storage medium. The method comprises obtaining vehicle impact parameters, simplifying a previously obtained vehicle-pier impact model through the vehicle parameters, obtaining axial displacement, lateral displacement and rotation angle of the nodes at both ends of the fiber beam element; according to the axial displacement, the lateral displacement and the rotation angle, the displacement component of the RC section at any position of the fiber beam element is calculated; based on the displacement component of the RC section of the fiber beam element, the deformation component of the RC section is obtained; according to the RC section deformation component, the first unloading stiffness matrix and the second unloading stiffness matrix at the RC section are obtained; based on the first unloading stiffness matrix and the second unloading stiffness matrix, the third unloading stiffness matrix at the RC section is obtained, and the eigenvalue of the third unloading stiffness matrix is determined; according to the eigenvalue, the pier damage is evaluated.

Description

Technical Field

[0001] This invention relates to the technical field of bridge health monitoring, and in particular to methods, devices, equipment and storage media for assessing damage to reinforced concrete bridge piers. Background Technology

[0002] Vehicle-to-bridge pier collisions have become a major hidden danger threatening the structural safety of urban bridges. Vehicle impacts often cause severe damage to bridge piers, greatly reducing the bridge's performance and even causing partial or complete collapse of the bridge structure. This not only results in huge economic losses but also seriously threatens the lives and property of the public. Reinforced concrete (RC) piers are the main load-bearing components of many highway bridges and urban viaducts. Therefore, developing a reasonable damage index model to quantitatively analyze the structural damage of reinforced concrete piers under vehicle impacts is crucial for effectively assessing the degree of damage and health status of the piers.

[0003] Limitations and shortcomings of existing technologies: Researchers have proposed different types of damage indices to quantify the damage degree of RC piers. The first type is based on displacement or deformation, which can be used to effectively assess the degree of bending failure of a structure. These models require first determining the maximum allowable displacement, section rotation angle, or curvature. However, these maximum allowable response values ​​are usually determined under the premise that the structure is mainly subjected to bending deformation. For members that undergo significant shear deformation, this type of damage index is often no longer applicable.

[0004] The second type of commonly used damage index is based on the strain energy absorbed by the component, or on a combination of structural response and absorbed strain energy. This type of damage index model was initially proposed by Park and Ang in 1985. Subsequent researchers have made numerous extensions and expansions to the Park-Ang model. However, the Park-Ang damage model and its extensions introduce an empirical parameter called the joint coefficient. This parameter often requires calculation using empirical formulas based on a large amount of experimental data, making the practical application of this model relatively complex and cumbersome.

[0005] The third type is damage indices defined based on structural strain. These models often assess the damage level of components based on the strain distribution of the RC section. For example, Japanese scholars Tsuchiya and Maekawa established a damage model based on fiber beam elements that considers multiaxial tension-compression-bending effects to assess the damage level of RC piers under seismic loads. However, these models often neglect the shear deformation of the RC piers. Numerous studies have shown that RC piers often experience significant shear failure under vehicle impact. Therefore, this type of damage is difficult to effectively apply for assessing the damage level of RC piers under vehicle impact.

[0006] The fourth category is damage indices defined based on structural dynamic characteristic parameters. These indices use changes in stiffness or modal parameters before and after damage to reflect the degree of damage to RC components. These models typically simplify RC piers as a single-degree-of-freedom system and obtain the dynamic characteristic parameters of the RC component before and after damage through push-over analysis. However, numerous studies have shown that the dynamic response of RC piers under vehicle impact loads often exhibits a complex multi-degree-of-freedom system, accompanied by complex axial tension-compression-bending-shear interactions. Summary of the Invention

[0007] In order to solve the technical problems existing in the prior art, the present invention provides a method, apparatus, equipment and storage medium for assessing damage to reinforced concrete bridge piers.

[0008] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0009] In a first aspect, in one embodiment of the present invention, a method for assessing damage to reinforced concrete bridge piers is provided, the method comprising the following steps:

[0010] Obtain the parameters of the impacting vehicle, simplify the pre-obtained vehicle-pier impact model using the vehicle parameters, and obtain the axial displacement, lateral displacement, and rotation angle of the nodes at both ends of the fiber beam element;

[0011] Based on the axial displacement, the lateral displacement, and the rotation angle, the displacement components of the RC section at any position of the fiber beam element are calculated.

[0012] Based on the displacement components of the RC section of the fiber beam element, the deformation components of the RC section are obtained;

[0013] Based on the deformation components of the RC section, obtain the first unloading stiffness matrix of the concrete in the global coordinate system and the second unloading stiffness matrix of the steel reinforcement in the global coordinate system at the RC section.

[0014] Based on the first unloading stiffness matrix and the second unloading stiffness matrix, the third unloading stiffness matrix at the RC section is obtained, and the eigenvalues ​​of the third unloading stiffness matrix are determined.

[0015] The damage to the bridge pier is assessed based on the aforementioned characteristic values.

[0016] As a further aspect of the present invention, before the steps of obtaining the impact vehicle parameters, simplifying the pre-obtained vehicle-pier impact model using the vehicle parameters, and obtaining the axial displacement, lateral displacement, and rotation angle of the nodes at both ends of the fiber beam element, the method further includes discretizing the RC pier into several fiber beam elements.

[0017] As a further aspect of the present invention, the displacement components at position x of the RC section include axial displacement u(x), lateral displacement v(x), and rotation angle θ(x); the axial displacement u(x), lateral displacement v(x), and rotation angle θ(x) are obtained by interpolation of the displacement components of the two end nodes.

[0018] As a further aspect of the present invention, the axial displacement u(x), lateral displacement v(x), and rotation angle θ(x) at the RC section position x are calculated using the following formulas:

[0019]

[0020] Where u1 is the axial displacement of the first node, u2 is the axial displacement of the second node, v1 is the lateral displacement of the first node, v2 is the lateral displacement of the second node, θ1 is the rotation angle of the first node, and θ2 is the rotation angle of the second node.

[0021] As a further aspect of the present invention, obtaining the 2×2 unloading stiffness matrix of concrete in the global coordinate system includes:

[0022] Determine the axial strain ε of the concrete at the RC section. x Lateral strain ε y and shear strain γ xy ;

[0023] Based on the stress-strain envelope of concrete, determine the unloading modulus of concrete on the two principal strain planes. and

[0024] Based on the unloading modulus of the two principal strain planes and Determine the first unloading stiffness matrix.

[0025] As a further aspect of the present invention, the unloading modulus based on the two principal strain planes and Determine the first unloading stiffness matrix, including:

[0026] Based on the unloading modulus of the two principal strain planes and The shear unloading modulus G of concrete in the two principal strain planes is obtained by the following formula. cu :

[0027]

[0028] The unloading stiffness matrix of concrete in the local coordinate system of the principal plane is obtained by the following formula.

[0029]

[0030] The unloading stiffness matrix of concrete in the global coordinate system can be obtained by the following formula.

[0031]

[0032] Where S is the transformation matrix, which is calculated according to the basic elastoplastic theory using the following formula:

[0033]

[0034] in, This represents the angle between the outward normal of the first principal strain plane and the x-axis;

[0035] According to the static condensation method, the fifth unloading stiffness matrix is... The first unloading stiffness matrix of the condensed concrete in the global coordinate system, where the first unloading stiffness moment is:

[0036] in, Represented as:

[0037]

[0038] Represented as:

[0039]

[0040] and The relationship between them is:

[0041]

[0042] As a further aspect of the present invention, the third unloading stiffness matrix at the RC section is obtained by integrating the first unloading stiffness matrix and the second unloading stiffness matrix at the RC section over the entire RC section.

[0043] Secondly, in another embodiment provided by the present invention, a reinforced concrete bridge pier damage assessment device is provided, the device comprising: a model construction module, a first calculation module, a second calculation module, a matrix construction module, an eigenvalue acquisition module, and an assessment module.

[0044] The model building module is used to obtain the parameters of the impacting vehicle, and to simplify the pre-obtained vehicle-pier impact model using the vehicle parameters to obtain the axial displacement, lateral displacement and rotation angle of the nodes at both ends of the fiber beam element.

[0045] The first calculation module is used to calculate the displacement components of the RC section at any position of the fiber beam element based on the axial displacement, lateral displacement and rotation angle of the nodes at both ends of the fiber beam element.

[0046] The second calculation module is used to obtain the deformation component of any RC section based on the displacement component at any location of the fiber beam element RC section.

[0047] The matrix construction module is used to obtain the first unloading stiffness matrix of concrete in the global coordinate system and the second unloading stiffness matrix of steel reinforcement in the global coordinate system based on the deformation components of the RC section.

[0048] The eigenvalue acquisition module is used to obtain a third unloading stiffness matrix at the RC section based on the first unloading stiffness matrix and the second unloading stiffness matrix, and to determine the eigenvalues ​​of the third unloading stiffness matrix.

[0049] The evaluation module is used to evaluate the vehicle damage based on the feature values.

[0050] Thirdly, in another embodiment of the present invention, an apparatus is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor loads and executes the computer program to implement the steps of a method for assessing damage to reinforced concrete bridge piers.

[0051] Fourthly, in another embodiment of the present invention, a storage medium is provided storing a computer program, which, when loaded and executed by a processor, implements the steps of the reinforced concrete bridge pier damage assessment method.

[0052] The technical solution provided by this invention has the following beneficial effects:

[0053] The present invention provides a method, apparatus, equipment and storage medium for assessing damage to reinforced concrete bridge piers. The proposed damage index effectively and reasonably quantifies the degree of damage to the RC section by changing the eigenvalues ​​of the unloading stiffness matrix, thereby achieving the goal of quantitatively assessing the damage to RC bridge piers under vehicle impact.

[0054] These or other aspects of the invention will become more apparent from the following description of embodiments. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0056] Figure 1 This is a flowchart of a method for assessing damage to reinforced concrete bridge piers according to an embodiment of the present invention.

[0057] Figure 2 This is a simplified multi-degree-of-freedom vehicle-pier impact model in a reinforced concrete bridge pier damage assessment method according to an embodiment of the present invention.

[0058] Figure 3 This is a definition of the nodal displacement components of fiber beam elements and the displacement components of the RC section at any location in the reinforced concrete bridge pier damage assessment method according to an embodiment of the present invention.

[0059] Figure 4 This invention relates to a method for assessing damage to reinforced concrete bridge piers, specifically the discretization of the RC section in a fiber beam element and the stress-strain state of the concrete.

[0060] Figure 5 In one embodiment of the present invention, the method for assessing damage to reinforced concrete bridge piers determines the concrete strain component based on the deformation component of the RC section.

[0061] Figure 6 The stress-strain curve of the compressed concrete in the damage assessment method for reinforced concrete bridge piers according to an embodiment of the present invention is shown.

[0062] Figure 7 This is an example of an embodiment of the present invention: the unloading-reloading curve of compressed concrete in a method for assessing damage to reinforced concrete bridge piers.

[0063] Figure 8 The stress-strain relationship envelope and unloading / reloading curve of tensile concrete in a method for assessing damage to reinforced concrete bridge piers according to an embodiment of the present invention are shown.

[0064] Figure 9 This is a bilinear stress-strain relationship model for reinforcing steel bars in a method for assessing damage to reinforced concrete bridge piers according to an embodiment of the present invention.

[0065] Figure 10 This refers to the two orthogonal principal strain planes of the concrete fibers in a method for assessing damage to reinforced concrete bridge piers according to an embodiment of the present invention.

[0066] Figure 11This is a detailed flowchart illustrating a specific example of damage assessment for reinforced concrete bridge piers according to an embodiment of the present invention.

[0067] Figure 12 This is a structural block diagram of a reinforced concrete bridge pier damage assessment device according to an embodiment of the present invention. Detailed Implementation

[0068] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0070] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0071] Specifically, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0072] Please see Figure 1 and Figure 11 , Figure 1 This is a flowchart of a method for assessing damage to reinforced concrete bridge piers provided in an embodiment of the present invention, such as... Figure 1 As shown, the method for assessing damage to reinforced concrete bridge piers includes steps S10 to S60.

[0073] S10. Obtain the parameters of the impacting vehicle, simplify the pre-obtained vehicle-pier impact model using the vehicle parameters, and obtain the axial displacement, lateral displacement, and rotation angle of the nodes at both ends of the fiber beam element.

[0074] The parameters of the vehicle involved in the collision include the vehicle's mass and the collision speed.

[0075] In an embodiment of the present invention, before the steps of obtaining the impact vehicle parameters, simplifying the pre-obtained vehicle-pier impact model using the vehicle parameters, and obtaining the axial displacement, lateral displacement, and rotation angle of the nodes at both ends of the fiber beam element, the method further includes discretizing the RC pier into several fiber beam elements.

[0076] Among them, the simplified vehicle-pier impact model is as follows: Figure 2 As shown; Figure 2 m v Indicates the concentrated vehicle mass, u v The displacement of the vehicle is represented by n, the number of discrete fiber beam elements is represented by n1 and n2, and the numbers of the two lumped masses coupled to the spring are represented by m. i Let u represent the mass of the i-th set (i = 1, 2, ..., n). i v i and θ i Let m represent the axial displacement, lateral displacement, and rotation angle of the i-th lumped mass, respectively. This simplified vehicle-pier impact model effectively considers multi-point impact problems. By assigning a lumped vehicle mass m... v By applying an initial velocity v0, this simplified vehicle-pier impact model can efficiently and accurately output the vehicle impact force time history and the dynamic response of the RC pier.

[0077] Specifically, each fiber beam element contains two nodes: a start node and an end node. Each node has three degrees of freedom: axial displacement u, lateral displacement v, and rotation angle θ.

[0078] S20. Based on the axial displacement, lateral displacement, and rotation angle of the nodes at both ends of the fiber beam element, calculate the displacement components of the RC section at any position of the fiber beam element.

[0079] In embodiments of the present invention, such as Figure 3 As shown, each fiber beam element contains two nodes: a start node and an end node. Each node has three degrees of freedom: axial displacement u, lateral displacement v, and rotation angle θ. Here, l represents the element length, and x defines the position of any RC section.

[0080] The displacement components of the RC section at position x include axial displacement u(x), lateral displacement v(x), and rotation angle θ(x); the axial displacement u(x), lateral displacement v(x), and rotation angle θ(x) are obtained by interpolation of the displacement components of the two end nodes.

[0081] The axial displacement u(x), lateral displacement v(x), and rotation angle θ(x) of the RC section at any position x are calculated using the following formulas:

[0082]

[0083] Where u1 is the axial displacement of the first node, u2 is the axial displacement of the second node, v1 is the lateral displacement of the first node, v2 is the lateral displacement of the second node, θ1 is the rotation angle of the first node, and θ2 is the rotation angle of the second node.

[0084] S30. Based on the displacement component at any point of the RC section of the fiber beam element, obtain the deformation component of any RC section.

[0085] In embodiments of the present invention, the deformation of the RC section at any RC section location x has three deformation components, namely: curvature κ(x), central axial strain ε0(x), and shear strain γ(x). Based on the plane section assumption, the three deformation components can be determined by the following formula:

[0086]

[0087] As can be seen from the above formula, the values ​​of κ(x), ε0, and γ are independent of x, meaning that the three deformation components of any section within the fiber beam element do not change with the position of the section. This is one of the fundamental assumptions adopted in the Timoshenko fiber beam element model of this invention.

[0088] S40. Based on the deformation components of the RC section, obtain the first unloading stiffness matrix of the concrete in the global coordinate system and the second unloading stiffness matrix of the steel reinforcement in the global coordinate system at the RC section.

[0089] The first unloading stiffness matrix and the second unloading stiffness matrix are 2×2 unloading stiffness matrices in the global coordinate system.

[0090] In an embodiment of the present invention, obtaining the first unloading stiffness matrix of concrete in the global coordinate system includes:

[0091] Specifically, the RC section is discretized into a series of concrete fibers and steel fibers, such as Figure 4 As shown. This fiber beam element model assumes that the cross-sectional shear force is entirely resisted by the concrete fibers, and the shear capacity of the reinforcing steel fibers is negligible. Therefore, the strain state of the reinforcing steel is determined by a uniaxial strain ε. x The strain state of concrete is described by three strain components: axial strain ε x Lateral strain ε y and shear strain γ xy The description is as follows: the three corresponding stress components are σ x σ y and τ xy ,like Figure 4 As shown.

[0092] S4011. Determine the axial strain ε of the concrete at the RC section. x Lateral strain ε y and shear strain γ xy .

[0093] Wherein, the axial strain ε of the concrete x and shear strain γ xyAll are determined by the three deformation components of the RC section, such as Figure 5 As shown; lateral strain ε y Then, based on the corresponding stress σ y The constraint condition ε = 0 was determined through iterative steps. The axial strain ε of the concrete... x and shear strain γ xy All are determined by the three deformation components of the RC section, which are based on the two fundamental assumptions that the RC section remains planar after deformation and that the shear strain is uniformly distributed throughout the entire section.

[0094] S4012, Based on the obtained axial strain ε of the concrete x Lateral strain ε y and shear strain γ xy The two principal strain planes and principal strains of concrete can be determined using elastoplastic theory. Furthermore, based on the stress-strain envelope of concrete, the unloading modulus of concrete on the two principal strain planes can be determined. and

[0095] In embodiments of the present invention, the concrete stress-strain envelope includes the stress-strain envelope of concrete under compression and the stress-strain envelope of concrete under tension.

[0096] In embodiments of the present invention, the stress-strain envelope of concrete under compression adopts the classic Kent-Park model, such as... Figure 6 and Figure 7 As shown in the figure, the loading and unloading characteristics of concrete are also described. In the figure, ε0 is taken as 0.002, representing the strain corresponding to the peak stress in the unconstrained concrete surrounding the stirrups. c K represents the compressive strength of concrete, ε is the strength enhancement factor of confined concrete related to the stirrup ratio, and K is the strength enhancement factor of confined concrete. u ε represents the ultimate strain of concrete. r and σ r ε represents the strain and stress corresponding to the unloading point on the envelope. e and ε p E represents the elastic and plastic strain components, respectively. cu This indicates the first unloading slope.

[0097] In embodiments of the present invention, the stress-strain envelope of tensile concrete is as follows: Figure 8 As shown, it is assumed that the concrete does not produce additional plastic strain under tension. In the figure, f t 'Is related to plastic strain ε p The relevant tensile strength of concrete, ε t0 It is the tensile strain ε that corresponds to the maximum tensile stress. tr and σtr E represents the strain and stress corresponding to the unloading point on the envelope. tu This indicates the second unloading slope.

[0098] Since elastic deformation can eventually fully recover, structural damage is actually caused by irreversible plastic deformation. Therefore, this invention defines a damage index based on the degree of plasticity of the fiber beam elements. During a vehicle-pier collision, the degree of plasticity in the structure continuously accumulates. During unloading, elastic deformation gradually recovers while plastic deformation stops increasing. Therefore, the value of the damage index should show a continuously increasing trend during the loading phase and gradually remain stable during the unloading phase.

[0099] Since the three deformation components of any section within the Timoshenko fiber beam element do not change with the section position, as shown in Equation (2), the damage degree of the fiber beam element can be characterized by the degree of plasticity of any RC section within the beam element. The degree of plasticity of the RC section is affected by the distribution of plastic strain in the fiber of the section. Figure 6 and Figure 7 It can be seen that the first unloading slope E of the concrete cu It will change with the plastic strain component ε of concrete p The unloading stiffness of the RC section gradually decreases as the fiber plasticity of the section increases. Therefore, the unloading stiffness of the RC section gradually degrades with the accumulation of fiber plasticity, and the degree of damage to the beam element can be characterized by the degradation of the unloading stiffness of any RC section in the fiber beam element.

[0100] S4013, Unloading modulus based on two principal strain planes and Determine the first unloading stiffness matrix of concrete in the global coordinate system.

[0101] Based on the assumptions of the fiber beam element model, the shear force on the fiber beam is entirely borne by the concrete, and the shear effect of the reinforcement is ignored; ε x , ε y γ xy These are the three strain components of concrete, σ x , σ y , τ xy These are the three stress components of concrete. During a vehicle impact, the pier undergoes elastoplastic deformation, and the strain components of the concrete undergoing elastic deformation are ε. e,x , ε e,y and γ e,xy The strain components of concrete undergoing plastic deformation are ε p,x , ε p,y and γ p,xy Based on the three elastic strain components (ε) of concrete e,x , ε e,y and γe,xy Give two orthogonal principal strain planes of concrete, such as Figure 10 As shown. Where σ1 and ε1 are the stress and strain components of the first principal strain plane, respectively, and σ2 and ε2 are the stress and stress components of the second principal strain plane, respectively, and ε represents the angle between the outward normal of the first principal strain plane and the x-axis.

[0102] The relationship between the above parameters is as follows:

[0103]

[0104] Where I1 and I2 are the strain invariants of the two principal strain planes of concrete, respectively, and their expressions are:

[0105]

[0106] ε e,x , ε e,y and γ e,xy The formula for calculation is:

[0107]

[0108] S40131, based on the obtained unloading modulus of the two strain planes and The shear unloading modulus G of concrete in the two principal strain planes is obtained by the following formula. cu :

[0109]

[0110] S40132, Due to the unloading stiffness matrix of concrete in the local coordinate system of the principal plane The main diagonal elements are respectively and G cu The 3×3 diagonal matrix; therefore, the fourth unloading stiffness matrix of concrete in the local coordinate system of the principal strain plane is obtained by the following formula.

[0111]

[0112] S40133. The fifth unloading stiffness matrix of concrete in the global coordinate system is obtained by the following formula.

[0113]

[0114] Define the transformation matrix as S, and calculate it using the following formula based on fundamental elastoplastic theory:

[0115]

[0116] in This represents the angle between the outward normal of the first principal strain plane and the x-axis, such as... Figure 10 As shown.

[0117] S40134. According to the static condensation method, the fifth unloading stiffness matrix is... The first unloading stiffness matrix of the condensed concrete in the global coordinate system (2×2)

[0118] in, Represented as:

[0119]

[0120] Represented as:

[0121]

[0122] and The relationship between them is:

[0123]

[0124] In this embodiment of the invention, obtaining the second unloading stiffness matrix of the reinforcing bar in the global coordinate system includes:

[0125] S4021. Based on the stress-strain curve of the reinforcing steel and the assumption of the plane section, determine the axial strain ε of the reinforcing steel at the RC section according to the three deformation components κ(x), ε0(x), and γ(x) of the RC section. x Determine the axial plastic strain ε of the reinforcing steel based on its strain history. p ;

[0126] S4022, Based on the axial strain ε of the reinforcing steel at the RC section x and axial plastic strain ε p The unloading modulus E of the reinforcing steel was determined using a bilinear stress-strain curve. s ;

[0127] The stress-strain envelope of the reinforcing steel is modeled using a bilinear model, such as... Figure 9 As shown, where f y E s and E t These represent the yield stress, elastic modulus, and hardening modulus of steel, respectively. The unloading and reloading process proceeds along a slope of E. s A straight line, such as Figure 7 As shown.

[0128] S4023. Based on the unloading modulus of the reinforcing bars, determine the second unloading stiffness matrix of the reinforcing bars in the global coordinate system (2×2). The second unloading stiffness matrix of the reinforcing bars in the global coordinate system (2×2) It is obtained by calculation using the following formula:

[0129]

[0130] S50. Based on the first unloading stiffness matrix and the second unloading stiffness matrix, obtain the third unloading stiffness matrix at the RC section, and determine the eigenvalues ​​of the third unloading stiffness matrix.

[0131] In this embodiment of the invention, obtaining the third unloading stiffness matrix at the RC section based on the first and second unloading stiffness matrices includes:

[0132] Third unloading stiffness matrix at RC section By and Integrating over the entire RC section yields:

[0133]

[0134] Among them, A con A represents the area of ​​concrete. steel Represents the area of ​​the reinforcing steel. The expression for I(y) is as follows:

[0135]

[0136] In this embodiment of the invention, the RC section is discretized into a series of concrete fibers and steel fibers. Based on the plane section assumption and the uniform distribution of shear stress in the plane, the strain of the fiber beam element at section x and section height y is defined as ε(x,y), ε(x,y)=[ε x γ xy ] T ,like Figure 5 As shown. ε(x,y) can be directly determined by the three deformation components κ(x), ε0(x), and γ(x) of the RC section at section x, i.e.

[0137]

[0138] Where I(y) is the compatibility matrix.

[0139] According to the constitutive relation of the material, the stress and stiffness at section x of the fiber beam element are defined as σ(x,y) and E(x,y), respectively. Figure 4 As shown.

[0140] in,

[0141]

[0142] Resistance of section x Fsec (x) can be obtained by integrating the stress σ(x,y) over the entire cross section, and its expression is as follows:

[0143]

[0144] Then the stiffness K at section x sec (x) can be derived from F sec (x) and d(x) are determined:

[0145]

[0146] Specifically, the degradation of the unloading stiffness of the RC section can be addressed by the unloading matrix at the RC section. The changes in the three eigenvalues ​​reflect this. Generally, as plastic deformation of the cross-section accumulates, all three eigenvalues ​​tend to decrease as the resistance of the RC cross-section decreases. This can be understood as follows: assuming a three-degree-of-freedom vibration device with three unit masses, the unloading matrix at the RC cross-section... Then the unloading matrix at the RC section The three eigenvalues ​​will represent three natural frequencies, which will decrease as the device stiffness matrix degenerates. Here, the unloading matrix at the RC section is... The three eigenvalues ​​at time t are defined as ω1(t), ω2(t), and ω3(t), respectively, where ω1(t)≤ω2(t)≤ω3(t).

[0147] S60. Assess the vehicle damage based on the characteristic values.

[0148] The damage index, obtained based on the three feature values, is calculated using the following formula:

[0149]

[0150] in represent The damage index corresponding to the i-th eigenvalue at time t, ω i (0) represents time 0 when the concrete has not been damaged. The i-th eigenvalue. D The value varies between 0.0 and 1.0, reflecting the degree of plasticity of the RC section. D =0.0 indicates fully recoverable elastic deformation, I D =1.0 indicates the complete loss of structural resistance.

[0151] This invention avoids the introduction of computationally complex empirical parameters, effectively controlling damage index values ​​between 0.0 and 1.0. Its theoretical approach is clear and reasonable, and its calculations are simple and convenient. It considers the influence of the tension-compression, bending, and shear coupling effects of the RC beam-column system at the fiber and material level, making it effective for assessing the structural damage of RC bridge piers in vehicle collisions. It not only obtains the structural damage degree of the RC bridge pier after a vehicle collision but also, through time-step analysis of the dynamic model, reveals the change in damage degree over time during the collision. Based on the fiber beam element model, the RC bridge pier is equivalent to a multi-degree-of-freedom system, allowing for the distribution of pier damage along the pier height, effectively identifying severely damaged locations and providing a reference for pier collision protection. The effective consideration of shear effects makes the model more universal, applicable not only to vehicle-RC bridge pier collision analysis but also to the field of bridge seismic resistance.

[0152] This invention, based on the Timoshenko fiber beam element model, considers a damage index model of axial tension-compression-bending-shear interaction to quantify the damage degree of RC piers under vehicle impact. The model describes the structural damage of the beam element through the degree of plasticity of the RC section, and the uniaxial stress-strain curve relationship of the concrete adopts the classic Kent-Park model. Since the unloading modulus of concrete in this material model continuously decreases with increasing plastic strain, the degree of plasticity of a single concrete fiber in the RC section can be effectively characterized by the magnitude of the fiber's unloading modulus. Therefore, the accumulation process of plastic deformation in the RC section can be effectively described by the continuous degradation of the section's unloading stiffness. Because the degradation of section stiffness directly leads to changes in the eigenvalues ​​of the stiffness matrix, the damage index proposed in this invention effectively and reasonably quantifies the damage degree of the RC section by changing the eigenvalues ​​of the RC section's unloading stiffness matrix, achieving the goal of quantitatively assessing the damage of RC piers under vehicle impact.

[0153] It should be understood that although the above description follows a certain order, these steps are not necessarily executed in that order. Unless otherwise expressly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, some steps in this embodiment may include multiple steps or multiple stages, which are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be performed alternately or in turn with other steps or at least a portion of the steps or stages in other steps.

[0154] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Furthermore, any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory.

[0155] In one embodiment, see Figure 12 As shown, an embodiment of the present invention also provides a reinforced concrete bridge pier damage assessment device, which includes a model construction module 100, a first calculation module 200, a second calculation module 300, a matrix construction module 400, an eigenvalue acquisition module 500, and an assessment module 600.

[0156] The model building module 100 is used to obtain the parameters of the impacting vehicle, simplify the pre-obtained vehicle-pier impact model using the vehicle parameters, and obtain the axial displacement, lateral displacement and rotation angle of the nodes at both ends of the fiber beam element.

[0157] The first calculation module 200 is used to calculate the displacement components of the RC section at any position of the fiber beam unit based on the axial displacement, lateral displacement and rotation angle of the nodes at both ends of the fiber beam unit.

[0158] The second calculation module 300 is used to obtain the deformation component of any RC section based on the displacement component at any location of the fiber beam element RC section.

[0159] The matrix construction module 400 is used to obtain the first unloading stiffness matrix of concrete in the global coordinate system and the second unloading stiffness matrix of steel reinforcement in the global coordinate system based on the deformation components of the RC section.

[0160] The feature value acquisition module 500 is used to obtain a third unloading stiffness matrix at the RC section based on the first unloading stiffness matrix and the second unloading stiffness matrix, and to determine the feature values ​​of the third unloading stiffness matrix.

[0161] The evaluation module 600 is used to evaluate the vehicle damage based on the feature values.

[0162] In one embodiment, the present invention also provides a device including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus.

[0163] Memory, used to store computer programs;

[0164] When a processor executes a computer program stored in memory, it executes the aforementioned method for assessing damage to reinforced concrete bridge piers. When the processor executes instructions, it implements the steps in the above-described method embodiments.

[0165] The communication bus mentioned in the above terminal can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0166] The communication interface is used for communication between the aforementioned terminal and other devices.

[0167] The memory may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0168] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0169] The device includes user equipment and network equipment. The user equipment includes, but is not limited to, computers, smartphones, and PDAs. The network equipment includes, but is not limited to, a single network server, a server group consisting of multiple network servers, or a cloud based on cloud computing, which is a type of distributed computing consisting of a super virtual computer composed of a group of loosely coupled computers. The device can operate independently to implement the invention, or it can connect to a network and interact with other devices on the network to implement the invention. The network in which the device operates includes, but is not limited to, the Internet, wide area networks (WANs), metropolitan area networks (MANs), local area networks (LANs), and VPN networks.

[0170] It should also be understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0171] In one embodiment of the present invention, a storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the steps in the above method embodiments.

[0172] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Furthermore, any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory.

[0173] It should be understood that, as used herein, the singular form "a" is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations of one or more of the associatedly listed items. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0174] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

[0175] It should be understood that, as used herein, the singular form "a" is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations of one or more of the associatedly listed items. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0176] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for assessing damage to reinforced concrete bridge piers, characterized in that, The method includes: Obtain the parameters of the impacting vehicle, simplify the pre-obtained vehicle-pier impact model using the vehicle parameters, and obtain the axial displacement, lateral displacement, and rotation angle of the nodes at both ends of the fiber beam element; Based on the axial displacement, the lateral displacement, and the rotation angle, the displacement components of the RC section at any position of the fiber beam element are calculated. Based on the displacement component at any point of the RC section of the fiber beam element, obtain the deformation component of any RC section. Based on the deformation components of the RC section, obtain the first unloading stiffness matrix of the concrete in the global coordinate system and the second unloading stiffness matrix of the steel reinforcement in the global coordinate system at the RC section. Based on the first unloading stiffness matrix and the second unloading stiffness matrix, the third unloading stiffness matrix at the RC section is obtained, and the eigenvalues ​​of the third unloading stiffness matrix are determined. The damage to the bridge pier is assessed based on the aforementioned characteristic values.

2. The method for assessing damage to reinforced concrete bridge piers as described in claim 1, characterized in that, Before the steps of obtaining the axial displacement, lateral displacement and rotation of the two end nodes of the fiber beam element by simplifying the vehicle-pier impact model based on the pre-input vehicle mass and collision speed, the process also includes discretizing the RC pier into several fiber beam elements.

3. The method for assessing damage to reinforced concrete bridge piers as described in claim 1, characterized in that, The location of the RC section The displacement components at that location include axial displacement. Lateral displacement and corner The axial displacement Lateral displacement and corner It is obtained by interpolation from the displacement components of the two end nodes.

4. The method for assessing damage to reinforced concrete bridge piers as described in claim 3, characterized in that, RC section position Axial displacement at Lateral displacement and corner It is calculated using the following formula: ； in, Let be the axial displacement of the first node. This represents the axial displacement of the second node. This represents the lateral displacement of the first node. This represents the lateral displacement of the second node. For the corner of the first node, For the corner of the second node, The unit length is denoted as .

5. The method for assessing damage to reinforced concrete bridge piers as described in claim 1, characterized in that, Obtain the first unloading stiffness matrix of concrete in the global coordinate system, including: Determine the axial strain of concrete at the RC section. Lateral strain and shear strain ; Based on the stress-strain envelope of concrete, determine the unloading modulus of concrete on the two principal strain planes. and ; Based on the unloading modulus of the two principal strain planes and Determine the first unloading stiffness matrix.

6. The method for assessing damage to reinforced concrete bridge piers as described in claim 5, characterized in that, The unloading modulus based on the two principal strain planes and Determine the first unloading stiffness matrix, including: Based on the unloading modulus of the two principal strain planes and The shear unloading modulus of concrete in the two principal strain planes is obtained through the following formula. : The fourth unloading stiffness matrix of concrete in the principal plane local coordinate system is obtained by the following formula. : ； The fifth unloading stiffness matrix of concrete in the global coordinate system is obtained by the following formula. : ； in, The transformation matrix is ​​calculated using the following formula based on fundamental elastoplastic theory. : ； in, Indicates the outward normal of the first principal strain plane and The included angle of the axis; According to the static condensation method, the fifth unloading stiffness matrix is... The first unloading stiffness matrix of the condensed concrete in the global coordinate system, where the first unloading stiffness moment is: : in, Represented as: ； Represented as: ； and The relationship between them is: 。 7. The method for assessing damage to reinforced concrete bridge piers as described in claim 1, characterized in that, The third unloading stiffness matrix at the RC section is obtained by integrating the first and second unloading stiffness matrices at the RC section over the entire RC section.

8. A device for assessing damage to reinforced concrete bridge piers, characterized in that, The device includes: a model building module, a first calculation module, a second calculation module, a matrix building module, an eigenvalue acquisition module, and an evaluation module; The model building module is used to obtain the parameters of the impacting vehicle, simplify the pre-obtained vehicle-pier impact model using the vehicle parameters, and obtain the axial displacement, lateral displacement and rotation angle of the nodes at both ends of the fiber beam element; The first calculation module is used to calculate the displacement components of the RC section at any position of the fiber beam element based on the axial displacement, lateral displacement and rotation angle of the nodes at both ends of the fiber beam element. The second calculation module is used to obtain the deformation component of any RC section based on the displacement component at any location of the fiber beam element RC section; The matrix construction module is used to obtain the first unloading stiffness matrix of concrete in the global coordinate system and the second unloading stiffness matrix of steel reinforcement in the global coordinate system at the RC section based on the deformation components of the RC section. The eigenvalue acquisition module is used to obtain a third unloading stiffness matrix at the RC section based on the first unloading stiffness matrix and the second unloading stiffness matrix, and to determine the eigenvalues ​​of the third unloading stiffness matrix. The evaluation module is used to evaluate the damage to the bridge pier based on the characteristic values.

9. An apparatus comprising a memory and a processor, the memory storing a computer program, the processor loading and executing the computer program to implement the steps of the reinforced concrete bridge pier damage assessment method as claimed in any one of claims 1-7.

10. A storage medium storing a computer program that, when loaded and executed by a processor, implements the steps of the method for assessing damage to reinforced concrete bridge piers as described in any one of claims 1-7.

Images