Method for evaluating horizontal bearing stability of ancient wood building

Abstract

The application discloses a kind of wood construction ancient building horizontal bearing stability evaluation method, comprising: step one, the mechanical property parameters of each wood component in wood construction ancient building are obtained;Step two, the three-dimensional entity geometric model of wood construction ancient building without column geometric defect is constructed;Step three, the measured inclination of each column in wood construction ancient building is measured;Step four, the mechanical simulation analysis model of wood construction ancient building without column geometric defect is established;Step five, the geometric defect of wood construction ancient building due to deterioration damage or / and external load action is simulated;Step six, the horizontal shear value of each column in wood construction ancient building is obtained;Step seven, column applies horizontal shear value, the stress state of wood construction ancient building is simulated;Step eight, the V j -U j Relationship curve of each column is drawn;Step nine, wood construction ancient building horizontal bearing stability index β v The application solves the technical problems that the traditional evaluation method is difficult to operate, has no quantitative index and is unsafe.

Description

Technical Field

[0001] This invention relates to the field of safety and stability of ancient wooden buildings, and in particular to a method for assessing the horizontal load-bearing stability of ancient wooden buildings. Background Technology

[0002] Ancient wooden buildings utilize mortise and tenon joints and bracket sets, along with the friction generated during construction, to connect components and form a load-bearing structural system. A key characteristic of ancient wooden buildings is the relatively high stiffness of the bracket sets, while the columns and beams connected by mortise and tenon joints have relatively weaker connection stiffness. After hundreds of years of deterioration or external loads, columns may slip or deform and cannot self-recover, exhibiting characteristics of a nonlinear discrete-body mechanical model. In contrast, modern building columns and beams possess strong connections and self-recovering characteristics of a continuous-body mechanical model. Therefore, the load-bearing mechanisms of ancient wooden buildings and modern buildings are completely different. Consequently, it is unscientific to use modern structural engineering methods to assess the stability of ancient wooden buildings.

[0003] Currently, many methods for dealing with geometric defects in ancient wooden columns caused by deterioration or external loads simply involve modifying the initial geometry of the analysis model based on measured data. This approach does not consider the impact of deformation on the internal forces of structural members. Therefore, using the method of modifying the initial geometry of the analysis model to assess the stability of ancient wooden buildings is inherently unsafe.

[0004] The "Technical Standard for Maintenance and Reinforcement of Ancient Wooden Buildings" stipulates in its assessment of ancient wooden buildings that "the structural analysis methods and calculation diagrams used to verify the load-bearing capacity of wooden components and systems should be subject to special verification." However, this standard does not provide clear calculation and analysis methods or quantitative indicators, making it difficult to assess the horizontal load-bearing stability of ancient wooden buildings after geometric defects have occurred.

[0005] Over hundreds of years, wooden ancient buildings have suffered from material deterioration and damage, as well as the effects of human activities and wars, resulting in tilting defects in the columns. These columns now merely float on the ground or the beams of the next floor, with weak connection rigidity. Currently, there are no clear methods or quantitative indicators to determine the horizontal load-bearing stability of wooden ancient buildings after these tilting defects occur, or at what magnitude of horizontal load would they become unstable.

[0006] Therefore, to address the above issues, it is necessary to adopt an analytical model that conforms to the load-bearing mechanism characteristics of ancient wooden buildings, and to take reasonable methods to evaluate the horizontal load-bearing stability of ancient wooden buildings. Summary of the Invention

[0007] The purpose of this invention is to provide a method for assessing the horizontal load-bearing stability of ancient wooden buildings, in order to solve the technical problems of traditional assessment methods being difficult to operate, lacking quantitative indicators, and being biased towards unsafety.

[0008] To achieve the above objectives, the present invention adopts the following technical solution.

[0009] A method for assessing the horizontal load-bearing stability of ancient wooden buildings includes the following steps.

[0010] Step 1: Number the columns of the wooden ancient building as 1, 2, ..., n; and obtain the mechanical property parameters of each wooden component in the wooden ancient building: the mechanical property parameters include the actual elastic modulus E, the actual density ρ, the shear modulus G, Poisson's ratio μ, and the tensile strength along the grain f. t Compressive strength along the grain f c Shear strength along the grain f v Flexural strength f m The coefficient of friction λ between the wooden components and the column; where n is the total number of columns.

[0011] Step two involves conducting on-site surveys and measurements to obtain the cross-sectional and length dimensions of the columns, beams, and brackets in the ancient wooden building, and then constructing a three-dimensional solid geometric model of the ancient wooden building without any geometric defects in the columns.

[0012] Step 3: Use a high-precision total station to conduct on-site measurements to obtain the measured tilt value Δ of each column in the wooden ancient building. j ; where j is the number of the j-th column, which is a natural number, and j≤n.

[0013] Step four: Combining the mechanical parameters of the timber in the ancient wooden structure obtained in step one and the three-dimensional solid geometric model of the ancient wooden structure without column geometric defects constructed in step two, a mechanical simulation analysis model of the ancient wooden structure without column geometric defects is established using ANSYS or ABAQUS simulation analysis software.

[0014] Step 5: Simulate geometric defects in the wooden ancient building caused by deterioration and / or external loads: Apply a horizontal displacement to the bottom of each column or a horizontal force to the top of each column in the mechanical simulation analysis model of the wooden ancient building without column geometric defects from Step 4. The horizontal displacement is based on the measured tilt value Δ of each column. j The application was performed; the initial tilt value Δ of each column in the mechanical simulation analysis model was obtained. j ', and calculate the tilt value Δ of all columns in the mechanical simulation analysis model respectively. j 'Compared with the measured tilt value Δ j The ratio Δ1' / Δ1, Δ2' / Δ2,..., Δ n ' / Δ n .

[0015] Step 6: Calculations show that 1.05 ≥ {Δ1' / Δ1, Δ2' / Δ2, ..., Δ...} n ' / Δ nThe requirement of ≥0.95 was then met, followed by wind tunnel testing: Based on the location of the wooden ancient building, the wind load with a recurrence period of w years was obtained, and this wind load was applied to the mechanical simulation analysis model of the wooden ancient building, which had already considered the geometric tilting defects of the columns in step five, to obtain the horizontal shear force value V of each column in the wooden ancient building. j '; w can be any value between 100 and 1000.

[0016] Step 7: Based on Step 5, first apply the structural self-weight to the mechanical simulation analysis model of the ancient wooden building that has already considered the geometric tilting defects of the columns, and then apply the horizontal shear force value V corresponding to the column in Step 6 to the top of each column. j ', and gradually increase the horizontal shear force V of each column. j ', until the wooden ancient building can no longer bear a greater load or collapses.

[0017] Step 8: Apply different horizontal shear force values ​​V to the j-th column. j ', Extract the horizontal shear force V of the j-th column at different times. j 'Horizontal deformation value U of column top relative to column base under action j And draw the V of the j-th column in the VU rectangular coordinate system. j -U j The relationship curve; where the horizontal deformation value U is used as the abscissa and the horizontal shear force value V is used as the ordinate.

[0018] Step nine, based on V obtained in step eight j -U j Relationship curve, let K j The point corresponds to V j -U j The origin of the coordinate system on the relationship curve and the peak value of the horizontal shear force V jmax At any point between, V j -U j The origin O and K of the relationship curve j Connecting wires, K j The area of ​​the triangle formed by the perpendicular line from the point to the U-axis and the U-axis is defined as g. j (u), from the origin O to K j Curves between points, K j The area of ​​the curvilinear shape enclosed by the perpendicular line from the point to the U-axis and the U-axis is defined as r. j (u), to obtain the area ratio θ j =g j (u) / r j (u).

[0019] Step 10, in V j -U j Select the peak horizontal shear force point V on the curvejmax The corresponding horizontal deformation value on the x-axis is U jm Let point {d} j1 d j2 , ..., d ji , ..., d jm} is V j -U j Points on the curve, with x-coordinates of {1 / m, 2 / m, ..., i / m, ..., m / m} × U jm , m > i; calculate the point {d j1 d j2 , ..., d ji , ..., d jm The area ratio of} is {θ} j1 θ j2 , ..., θ ji , ..., θ jm}

[0020] Step 11, if d j(i-1) Satisfying {θ ji , ..., θ jm} are all < α, and θ j(i-1) ≥α; Set the origin O and d j(i-1) Connect the points and extend the line to obtain a straight line L1, which passes through the peak point of the horizontal shear force V. jmax Draw a perpendicular line L2 to the vertical axis; the line L1 intersects the perpendicular line L2 at point Q. j Click, pass Q j Draw a perpendicular line L3 from point V to the x-axis. j -U j The relationship curves intersect at F j Point, F j Point α is taken as the yield point of the horizontal bearing stability of the column; where α = 0.97 and m ≥ 100.

[0021] Step 12: Following the methods in steps 8 to 11, obtain the V value for each column. j -U j The horizontal bearing capacity yield point F on the relationship curve j The corresponding horizontal deformation value u j Obtain the minimum horizontal deformation value u among all columns. min .

[0022] Step thirteen, based on the V of each column j -U j The relationship curve is used to obtain the minimum horizontal deformation value u. min The horizontal shear force V corresponding to each column jm And sum to get V sum .

[0023] Step fourteen: Based on the calculation results in step six, extract the horizontal shear force value V of each column in the ancient wooden building. j ', and sum them to get V' sum .

[0024] Step 15, based on V obtained in Steps 13 and 14 sum and V' sum Calculate the horizontal load-bearing stability index β of the ancient wooden building v :

[0025] β v =V sum / V' sum .

[0026] Step sixteen, when β v When the value is ≥3.0, the horizontal load-bearing stability of the ancient wooden building meets the evaluation requirements, and the evaluation is now complete.

[0027] Preferably, the actual elastic modulus E of the wooden ancient building includes E L E R and E T The shear modulus G of ancient wooden buildings includes the shear modulus G along the grain to the tangential plane. LT Parallel-radial shear modulus G LR and cross-sectional shear modulus G RT The Poisson's ratio for ancient wooden buildings includes the longitudinal-radial Poisson's ratio υ. LR Poisson's ratio in cross section υ RT Harmony pattern - Poisson's ratio of tangential surface υ LT Where L represents the direction of the wood grain, R represents the radial direction of the wood cross section, and T represents the tangential direction of the wood.

[0028] Preferably, the actual elastic modulus E of timber in the direction of grain in ancient wooden buildings. L The actual density ρ of the wooden ancient building was obtained through in-situ testing of the wooden ancient building; the actual radial elastic modulus E of the timber cross-section in the wooden ancient building. R Actual tangential modulus of elasticity E of wood T The shear modulus G, Poisson's ratio υ, and the coefficient of friction λ between wooden components were obtained by sampling the timber of ancient wooden buildings and conducting material mechanics tests.

[0029] Preferably, the method for establishing a mechanical simulation analysis model of the ancient wooden building without column geometric defects in step four is as follows: First, a three-dimensional solid numerical discrete analysis model containing the columns, beams, and brackets of the ancient wooden building is established using computer numerical simulation analysis software; then, contact elements are set at the contact interface of adjacent wooden components in the three-dimensional solid numerical discrete analysis model to simulate the frictional force parameters between the wooden components; the analysis method adopts the Newton-Raphson nonlinear iterative method to solve the problem, taking into account the geometric nonlinear effects of the structural system.

[0030] Preferably, based on preliminary calculations, if 1.05 ≥ {Δ1' / Δ1, Δ2' / Δ2, ..., Δ...} is not satisfied... n ' / Δ n To meet the requirement of ≥0.95, increase the applied horizontal displacement or force, and recalculate until 1.05 ≥ {Δ1' / Δ1, Δ2' / Δ2, ..., Δ n ' / Δ n The requirement is ≥0.95.

[0031] Preferably, when the column has a side length Δ during the construction period, the side length Δ of the column during the construction period is determined in step two according to the construction method of the ancient wooden building; the side length Δ of the column is 1% of the column length;

[0032] Step 3: Use a high-precision total station to conduct on-site measurements to obtain the actual tilt value of the columns in the ancient wooden structure; then subtract the column side length Δ obtained in Step 2 to obtain the actual geometric tilt defect value Δ of the columns in the ancient wooden structure. j .

[0033] Preferably, in step seven, the horizontal shear force V of each column is gradually increased. j The specific method is as follows: First, obtain the minimum horizontal shear force value V among all the columns in the ancient wooden building. jmin ', the horizontal shear force V borne by the remaining columns j Divide by the minimum horizontal shear force value V respectively jmin ', thus obtaining the coefficient K j ; Horizontal shear force V of each column j 'All according to K j Apply double the amount.

[0034] Preferably, when β is calculated in step fifteen v <3.0, reinforcement measures are taken for ancient wooden buildings to improve their horizontal stability and load-bearing capacity.

[0035] Compared with the prior art, the present invention has the following features and beneficial effects.

[0036] 1. This invention proposes a scientific, feasible, and easy-to-operate method for assessing the horizontal load-bearing stability of ancient wooden buildings. Compared with current stability assessment methods, the method in this invention adopts a discrete body mechanics analysis model, which considers the load-bearing mechanism characteristics of ancient wooden buildings relying on frictional contact between components and the initial defects of geometric tilting of columns caused by the deterioration and damage of ancient wooden buildings. At the same time, it provides a clear stability assessment method, which solves the technical problems that the standard is difficult to operate in practice, lacks quantitative indicators, and is biased towards unsafety.

[0037] 2. The method for assessing the horizontal load-bearing stability of ancient wooden buildings in this invention uses columns as the assessment object, quantifies the horizontal load-bearing stability index of ancient wooden buildings, and has important practical significance for assessing the horizontal load-bearing stability of ancient wooden buildings. Attached Figure Description

[0038] The present invention will now be described in further detail with reference to the accompanying drawings.

[0039] Figure 1 This is an overall schematic diagram of a single-story ancient wooden structure in an embodiment of the present invention.

[0040] Figure 2 This is a partial schematic diagram of a single-story ancient wooden structure in an embodiment of the present invention.

[0041] Figure 3 This is a schematic diagram showing the numbering of the columns in this invention.

[0042] Figure 4 This is a schematic diagram of the tilting defect of the column in this invention.

[0043] Attached diagram labels: 1 - column, 1a - outer channel column, 1b - inner channel column, 2 - bracket, 3 - beam, 3a - circumferential beam, 3b - radial beam. Detailed Implementation

[0044] This method for assessing the horizontal load-bearing stability of ancient wooden buildings uses columns as the evaluation object and includes the following steps.

[0045] Step 1, select as follows Figure 1 , Figure 2 The single-story wooden ancient building shown has its columns numbered. The column numbers can be found here. Figure 3 The single-story wooden ancient building includes columns 1, brackets 2, and beams 3. There are 32 columns 1 in total, divided into outer groove columns 1a and inner groove columns 1b. There are 24 outer groove columns 1a, arranged at intervals along the circumference. There are 8 inner groove columns 1b, arranged at intervals along the circumference. The 8 inner groove columns 1b are arranged within the circle formed by the 24 outer groove columns 1a. The beams 3 are divided into circumferential beams 3a and radial beams 3b. The circumferential beams 3a connect adjacent circumferential columns 1. The radial beams 3b connect adjacent radial circumferential beams 3a or between outer groove columns 1a and inner groove columns 1b. The brackets 2 are located between the columns 1 and the beams 3. Then, stress wave detectors, impedance meters, and materials mechanics experiments are used to obtain the mechanical properties of the wood in each component of the wooden ancient building.

[0046] The actual elastic modulus E of wood along the grain in ancient wooden buildings LThe actual density ρ of the wooden ancient building was obtained through in-situ testing. In this embodiment, in-situ non-destructive testing was performed on all components of the wooden ancient building; in other embodiments, in-situ non-destructive testing could be performed on most components. The actual density ρ of the wood used for the columns and the elastic modulus E along the grain of the wood used for the columns... L As shown in Table 1.

[0047] Table 1

[0048]

[0049] The actual radial elastic modulus E of timber cross-section in ancient wooden buildings R Actual tangential modulus of elasticity E of wood T The shear modulus G, Poisson's ratio υ, and coefficient of friction λ between timber components were obtained by sampling the timber of the ancient wooden building and conducting material mechanics tests, as shown in Table 2. In this implementation example, since it is an ancient wooden building, only a small number of samples could be taken from key load-bearing components or severely damaged components. The parameters of other components were based on these sampling test results.

[0050] In ancient wooden buildings, the shear modulus G of timber includes the shear modulus G along the grain to the tangential plane. LT The longitudinal-radial shear modulus G of wood LR and the cross-sectional shear modulus G of wood RT Poisson's ratio includes the parallel-radial Poisson's ratio υ. LR Poisson's ratio in cross section υ RT Harmony pattern - Poisson's ratio of tangential surface υ TL The subscript L indicates the direction of the wood along the grain, the subscript R indicates the radial direction of the wood cross section, and the subscript T indicates the tangential direction of the wood.

[0051] Table 2

[0052]

[0053]

[0054] The friction coefficient between the wooden components is λ = 0.3, which was obtained through sampling tests.

[0055] Step two involves on-site investigation and measurement to obtain the cross-sectional and length dimensions of the columns, beams, and brackets in the ancient wooden building. A three-dimensional solid geometric model of the ancient wooden building without any geometric defects in the columns is then constructed, such as... Figure 1 and Figure 2 .

[0056] Step 3: Use a high-precision total station to conduct on-site measurements and obtain the measured tilt value Δ of the columns in the wooden ancient building. j Table 3 below shows a schematic diagram of the column tilting defect. Figure 4 , j is the number of the j-th column, and is a natural number.

[0057] Table 3

[0058]

[0059]

[0060] Step four: Combining the mechanical parameters of the timber in the ancient wooden structure obtained in step one and the three-dimensional solid geometric model of the ancient wooden structure without column geometric defects constructed in step two, a mechanical simulation analysis model of the ancient wooden structure without column geometric defects is established using ANSYS or ABAQUS simulation analysis software. First, a three-dimensional solid numerical discrete analysis model containing the columns, beams, and brackets of the ancient wooden structure is established using computer numerical simulation analysis software. Then, contact elements are set at the contact interface of adjacent wooden components in the three-dimensional solid numerical discrete analysis model to simulate the frictional force parameters between the wooden components. The analysis method adopts the Newton-Raphson nonlinear iterative method to solve the problem, taking into account the geometric nonlinear effects of the structural system.

[0061] Step 5: Simulate geometric defects in the wooden ancient building caused by deterioration and / or external loads: Apply a horizontal displacement to the bottom of each column or a horizontal force to the top of each column in the mechanical simulation analysis model of the wooden ancient building without column geometric defects from Step 4. The horizontal displacement is based on the measured tilt value Δ of each column. j The application was performed; the initial tilt value Δ of each column in the mechanical simulation analysis model was obtained. j ', and calculate the tilt value Δ of all columns in the mechanical simulation analysis model respectively. j 'Compared with the measured tilt value Δ j The ratio Δ1' / Δ1, Δ2' / Δ2,..., Δ n ' / Δ n As shown in Table 4.

[0062] Table 4

[0063]

[0064]

[0065] Preliminary calculations show that 1.05 ≥ {Δ1' / Δ1, Δ2' / Δ2, ..., Δ...} does not satisfy the condition. j ' / Δ j To meet the requirement of ≥0.95, the applied horizontal displacement value or applied horizontal force was increased, and the calculation was repeated to obtain the ratio of the column tilt value in the mechanical simulation analysis model to the measured column tilt value, as shown in Table 5.

[0066] Table 5

[0067]

[0068]

[0069] Calculations show that 1.05 ≥ {Δ1' / Δ1, Δ2' / Δ2, ..., Δ3' / Δ j The requirement is ≥0.95.

[0070] Step Six: Conduct wind tunnel tests: Based on the location of the wooden ancient building, obtain the wind load with a recurrence period of w = 1000 years that the wooden ancient building will withstand. Apply this wind load to the mechanical simulation analysis model of the wooden ancient building, which has already considered the geometric tilting defects of the columns in Step Five, to obtain the horizontal shear force value V of each column in the wooden ancient building. j As shown in Table 6.

[0071] Table 6

[0072]

[0073] Step 7: Based on Step 5, first apply the structural self-weight to the mechanical simulation analysis model of the ancient wooden building that has already considered the geometric tilting defects of the columns, and then apply the horizontal shear force value V corresponding to the column in Step 6 to the top of each column. j ', and gradually increase the horizontal shear force V of each column. j ', until the wooden ancient building can no longer bear a greater load or collapses.

[0074] Step 8: Apply different horizontal shear force values ​​V to the j-th column. j ', Extract the horizontal shear force V of the j-th column at different times. j 'Horizontal deformation value U of column top relative to column base under action j And draw the V of the j-th column in the VU rectangular coordinate system. j -U j The relationship curve; where the horizontal deformation value U is the abscissa and the horizontal shear force value V is the ordinate; as shown in other supporting documents.

[0075] Step nine, based on V obtained in step eight j -U j Relationship curve, let K j The point corresponds to V j -U j The origin of the coordinate system on the relationship curve and the peak value of the horizontal shear force V jmax At any point between, V j -U j The origin O and K of the relationship curve j Connecting wires, K jThe area of ​​the triangle formed by the perpendicular line from the point to the U-axis and the U-axis is defined as g. j (u), from the origin O to K j Curves between points, K j The area of ​​the curvilinear shape enclosed by the perpendicular line from the point to the U-axis and the U-axis is defined as r. j (u), to obtain the area ratio θ j =g j (u) / r j (u);

[0076] Step 10, in V j -U j Select the peak horizontal shear force point V on the curve jmax The corresponding horizontal deformation value on the x-axis is U jm Let point {d} j1 d j2 , ..., d ji , ..., d jm} is V j -U j Points on the curve, with x-coordinates of {1 / m, 2 / m, ..., i / m, ..., m / m} × U jm , m > i; calculate the point {d j1 d j2 , ..., d ji , ..., d jm The area ratio of} is {θ} j1 θ j2 , ..., θ ji , ..., θ jm};

[0077] Step 11, if d j(i-1) Satisfying {θ ji , ..., θ jm} are all < α, and θ j(i-1) ≥α; Set the origin O and d j(i-1) Connect the points and extend the line to obtain a straight line L1, which passes through the peak point of the horizontal shear force V. jmax Draw a perpendicular line L2 to the vertical axis; the line L1 intersects the perpendicular line L2 at point Q. j Click, pass Q j Draw a perpendicular line L3 from point V to the x-axis. j -U j The relationship curves intersect at F j Point, F j Point α is taken as the yield point of the horizontal bearing stability of the column; where α = 0.97 and m = 150.

[0078] Step 12: Following the methods in steps 8 to 11, obtain the V value for each column. j -Uj The horizontal bearing capacity yield point F on the relationship curve j The corresponding horizontal deformation value u j Obtain the minimum horizontal deformation value u among all columns. min As shown in Table 7.

[0079] Table 7

[0080]

[0081]

[0082] Obtain the minimum deformation value u min =120mm.

[0083] Step thirteen, based on the V of each column j -U j The relationship curve is obtained at u min At a shear rate of 120mm, the corresponding horizontal shear force values ​​V for each column are {230.1, 178.5, 178.3, 170.2, 148.5, 158.6, 174.2, 160.4, 138.7, 90.2, 34.6, 45.2, 104.3, 44.1, 39.8, 182.9, 161.2, 152.4, 192.7, 196.5, 195.5, 264.2, 275.1, 259.2, 218.5, 167.4, 158.5, 144.8, 166.2, 163.5, 172.4, 238.1}, and summed to obtain V. sum =5204.9KN.

[0084] Step fourteen: Based on the calculation results in step six, extract the horizontal shear force value V of each column in the ancient wooden building. j ', and sum them to get V' sum =1649kN.

[0085] Step 15, based on V obtained in Steps 13 and 14 sum and V' sum Calculate the horizontal load-bearing stability index β of the ancient wooden building v :

[0086] β v =V sum / V' sum =5204.9 / 1649=3.2.

[0087] Step sixteen, β v =3.2≥3.0, the horizontal load-bearing stability of this ancient wooden building meets the assessment requirements, and no measures need to be taken to improve its horizontal stability load-bearing capacity.

[0088] In this embodiment, the column side foot is the way that the column foot of the ancient wooden building extends from the inside of the column frame plane to the outside. The side foot length Δ is the horizontal distance between the center of the column foot and the center of the column top, which is generally 1% of the column length.

[0089] The above embodiments are not exhaustive examples of specific implementation methods, and other embodiments are also possible. The purpose of the above embodiments is to illustrate the present invention, rather than to limit the scope of protection of the present invention. All applications derived from simple variations of the present invention fall within the scope of protection of the present invention.

Claims

1. A method for evaluating the horizontal load-bearing stability of ancient wooden buildings, characterized in that, The steps include the following: Step 1: Number the columns of the wooden ancient building as 1, 2, ..., n; and obtain the mechanical property parameters of each wooden component in the wooden ancient building: the mechanical property parameters include the actual elastic modulus E, the actual density ρ, the shear modulus G, Poisson's ratio μ, and the tensile strength along the grain f. t Compressive strength along the grain f c Shear strength along the grain f v Flexural strength f m The coefficient of friction λ between the wooden components and the column; where n is the total number of columns; Step 2: Using on-site surveys and measurements, obtain the cross-sectional and length dimensions of the columns, beams, and brackets in the wooden ancient building, and construct a three-dimensional solid geometric model of the wooden ancient building without geometric defects in the columns. Step 3: Use a high-precision total station to conduct on-site measurements to obtain the measured tilt value Δ of each column in the wooden ancient building. j Where j is the number of the j-th pillar, which is a natural number, and j≤n; Step 4: Combining the mechanical parameters of the timber in the ancient wooden building obtained in Step 1 and the three-dimensional solid geometric model of the ancient wooden building without column geometric defects constructed in Step 2, use ANSYS or ABAQUS simulation analysis software to establish a mechanical simulation analysis model of the ancient wooden building without column geometric defects. Step 5: Simulate geometric defects in the wooden ancient building caused by deterioration and / or external loads: Apply a horizontal displacement to the bottom of each column or a horizontal force to the top of each column in the mechanical simulation analysis model of the wooden ancient building without column geometric defects from Step 4. The horizontal displacement is based on the measured tilt value Δ of each column. j The application was performed; the initial tilt value Δ of each column in the mechanical simulation analysis model was obtained. j ', and calculate the tilt value Δ of all columns in the mechanical simulation analysis model respectively. j 'Compared with the measured tilt value Δ j The ratio Δ1' / Δ1, Δ2' / Δ2,..., Δ n ' / Δ n ; Step 6: Calculations show that 1.05 ≥ {Δ1' / Δ1, Δ2' / Δ2, ..., Δ...} n ' / Δ n The requirement of ≥0.95 was then met, followed by wind tunnel testing: Based on the location of the wooden ancient building, the wind load with a recurrence period of w years was obtained, and this wind load was applied to the mechanical simulation analysis model of the wooden ancient building, which had already considered the geometric tilting defects of the columns in step five, to obtain the horizontal shear force value V of each column in the wooden ancient building. j '; w can be any value between 100 and 1000; Step 7: Based on Step 5, first apply the structural self-weight to the mechanical simulation analysis model of the ancient wooden building that has already considered the geometric tilting defects of the columns, and then apply the horizontal shear force value V corresponding to the column in Step 6 to the top of each column. j ', and gradually increase the horizontal shear force V of each column. j ', until the wooden ancient building can no longer bear a greater load or collapses; Step 8: Apply different horizontal shear force values ​​V to the j-th column. j ', Extract the horizontal shear force V of the j-th column at different times. j 'Horizontal deformation value U of column top relative to column base under action j And draw the V of the j-th column in the VU rectangular coordinate system. j -U j The relationship curve; where the horizontal deformation value U is the horizontal axis and the horizontal shear force value V is the vertical axis; Step nine, based on V obtained in step eight j -U j Relationship curve, let K j The point corresponds to V j -U j The origin of the coordinate system on the relationship curve and the peak value of the horizontal shear force V jmax At any point between, V j -U j The origin O and K of the relationship curve j Connecting wires, K j The area of ​​the triangle formed by the perpendicular line from the point to the U-axis and the U-axis is defined as g. j (u), from the origin O to K j Curves between points, K j The area of ​​the curvilinear shape enclosed by the perpendicular line from the point to the U-axis and the U-axis is defined as r. j (u), to obtain the area ratio θ j =g j (u) / r j (u); Step 10, in V j -U j Select the peak horizontal shear force point V on the curve jmax The corresponding horizontal deformation value on the x-axis is U jm Let point {d} j1 d j2 , ..., d ji , ..., d jm } is V j -U j Points on the curve, with x-coordinates of {1 / m, 2 / m, ..., i / m, ..., m / m} × U jm , m > i; calculate the point {d j1 d j2 , ..., d ji , ..., d jm The area ratio of} is {θ} j1 θ j2 , ..., θ ji , ..., θ jm }; Step 11, if d j(i-1) Satisfying {θ ji , ..., θ jm } are all < α, and θ j(i-1) ≥α; Set the origin O and d j(i-1) Connect the points and extend the line to obtain a straight line L1, which passes through the peak point of the horizontal shear force V. jmax Draw a perpendicular line L2 to the vertical axis; the line L1 intersects the perpendicular line L2 at point Q. j Click, pass Q j Draw a perpendicular line L3 from point V to the x-axis. j -U j The relationship curves intersect at F j Point, F j Point 1 is taken as the yield point of the horizontal bearing stability of the column; where α = 0.97, m ≥ 100; Step 12: Following the methods in steps 8 to 11, obtain the V value for each column. j -U j The horizontal bearing capacity yield point F on the relationship curve j The corresponding horizontal deformation value u j Obtain the minimum horizontal deformation value u among all columns. min ; Step thirteen, based on the V of each column j -U j The relationship curve is used to obtain the minimum horizontal deformation value u. min The horizontal shear force V corresponding to each column jm And sum to get V sum ; Step fourteen: Based on the calculation results in step six, extract the horizontal shear force value V of each column in the ancient wooden building. j ', and sum them to get V' sum ; Step 15, based on V obtained in Steps 13 and 14 sum and V' sum Calculate the horizontal load-bearing stability index β of the ancient wooden building v : β v =V sum / V' sum ; Step sixteen, when β v When the value is ≥3.0, the horizontal load-bearing stability of the ancient wooden building meets the evaluation requirements, and the evaluation is now complete.

2. The method for evaluating the horizontal load-bearing stability of ancient wooden buildings according to claim 1, characterized in that: The actual elastic modulus E of ancient wooden buildings includes E L E R and E T The shear modulus G of ancient wooden buildings includes the shear modulus G along the grain to the tangential plane. LT Parallel-radial shear modulus G LR and cross-sectional shear modulus G RT The Poisson's ratio for ancient wooden buildings includes the longitudinal-radial Poisson's ratio υ. LR Poisson's ratio in cross section υ RT Harmony pattern - Poisson's ratio of tangential surface υ LT Where L represents the direction of the wood grain, R represents the radial direction of the wood cross section, and T represents the tangential direction of the wood.

3. The method for evaluating the horizontal load-bearing stability of ancient wooden buildings according to claim 2, characterized in that: The actual elastic modulus E of wood along the grain in ancient wooden buildings L The actual density ρ of the wooden ancient building was obtained through in-situ testing of the wooden ancient building; the actual radial elastic modulus E of the timber cross-section in the wooden ancient building. R Actual tangential modulus of elasticity E of wood T The shear modulus G, Poisson's ratio υ, and the coefficient of friction λ between wooden components were obtained by sampling the timber of ancient wooden buildings and conducting material mechanics tests.

4. The method for evaluating the horizontal load-bearing stability of ancient wooden buildings according to claim 1, characterized in that: The method for establishing a mechanical simulation analysis model of a wooden ancient building without column geometric defects in step four is as follows: First, a three-dimensional solid numerical discrete analysis model containing columns, beams and brackets of the wooden ancient building is established using computer numerical simulation analysis software; then, contact elements are set at the contact interface of adjacent wooden components in the three-dimensional solid numerical discrete analysis model to simulate the friction parameters between the wooden components. The analysis method employs the Newton-Raphson nonlinear iterative method, taking into account the geometric nonlinear effects of the structural system.

5. The method for evaluating the horizontal load-bearing stability of ancient wooden buildings according to claim 1, characterized in that: Preliminary calculations show that if 1.05 ≥ {Δ1' / Δ1, Δ2' / Δ2, ..., Δ...} is not satisfied... n ' / Δ n To meet the requirement of ≥0.95, increase the applied horizontal displacement or force, and recalculate until 1.05 ≥ {Δ1' / Δ1, Δ2' / Δ2, ..., Δ n ' / Δ n The requirement is ≥0.

95.

6. The method for evaluating the horizontal load-bearing stability of ancient wooden buildings according to claim 1, characterized in that: When the column has a side length Δ during the construction period, the side length Δ of the column during the construction period is determined in step two according to the construction method of the ancient wooden building; the side length Δ of the column is 1% of the column length; Step 3: Use a high-precision total station to conduct on-site measurements to obtain the actual tilt value of the columns in the ancient wooden structure; then subtract the column side length Δ obtained in Step 2 to obtain the actual geometric tilt defect value Δ of the columns in the ancient wooden structure. j .

7. The method for evaluating the horizontal load-bearing stability of ancient wooden buildings according to claim 1, characterized in that: In step seven, the horizontal shear force V of each column is gradually increased. j The specific method is as follows: First, obtain the minimum horizontal shear force value V among all the columns in the ancient wooden building. jmin ', the horizontal shear force V borne by the remaining columns j Divide by the minimum horizontal shear force value V respectively jmin ', thus obtaining the coefficient K j ; Horizontal shear force V of each column j 'All according to K j Apply double the amount.

8. The method for evaluating the horizontal load-bearing stability of ancient wooden buildings according to claim 1, characterized in that: When β is calculated in step fifteen v <3.0, reinforcement measures are taken for ancient wooden buildings to improve their horizontal stability and load-bearing capacity.

Images