Ancient wood residual strength prediction method applied to ancient building wood structure vibration table test

Abstract

The invention discloses an ancient wood residual strength prediction method applied to an ancient building wood structure vibration table test, and belongs to the technical field of ancient wood testing. The method comprises the following steps: S1, determining the type and the production place of an ancient wood to be predicted; s2, according to the determined wood type and production place, selecting new wood of the same type and production place to process the test piece; s3, carrying out a wood load lasting effect test on the processed test piece; the wood load persistent effect test comprises a wood rift-grain bending load persistent effect test and a wood rift-grain compression load persistent effect test; s4, calibrating model parameters in a wood cumulative damage model according to a result of the wood load lasting effect test; and S5, according to the wood cumulative damage model after parameter calibration, obtaining an ancient wood residual strength prediction formula by means of derivation and solution, and performing ancient wood residual strength prediction. According to the method, the universality and accuracy of prediction of the residual wood strength of the ancient building can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ancient wood testing, and in particular relates to an ancient wood residual strength prediction method applied to a shaking table test of an ancient building wooden structure. Background Art

[0002] Ancient buildings are the most important part of my country's countless material cultural heritage, with precious historical, artistic and scientific research value. At the same time, as a carrier of ancient cultural heritage, the importance of ancient buildings is self-evident. Earthquake disasters occur frequently in my country, with the characteristics of high frequency, high intensity, shallow epicenter and wide distribution. Earthquakes can cause different degrees of damage to ancient wooden buildings, such as loose mortise and tenon joints, tilted structures, and even overall collapse. Therefore, it is an urgent and important task to explore the destruction mechanism of ancient buildings under earthquakes and then strengthen and protect them. Among them, the vibration table test of ancient wooden buildings is the most widely used intuitive research method. To conduct the vibration table test of ancient wooden buildings, it is necessary to make a test model first. However, the wood of ancient buildings is different from new wood. The wood of ancient buildings has been used as a structural component for hundreds of years. Due to the influence of long-term load, the wood will creep and damage accumulate to varying degrees, which will deteriorate the material performance. Therefore, it is necessary to predict the residual strength of the materials used in ancient wooden buildings under long-term loads through reasonable methods to ensure the consistency between the vibration table test model of ancient wooden buildings and the original ancient wooden buildings, and improve the accuracy of the test results.

[0003] The core of the residual strength prediction method of ancient wood in the shaking table test of ancient building wooden structure is to clarify the duration of load effect of wood. The duration of load (DOL effect) of wood refers to the phenomenon that the deformation of wood gradually increases and the strength gradually decreases as the load duration increases. In response to this DOL effect, a certain degree of research has been conducted at home and abroad, mainly including wood DOL test, theoretical prediction model based on test and other methods.

[0004] However, most of the current systematic research on the DOL effect of wood at home and abroad focuses on predicting the service life of wood structures, and few studies focus on directly deriving the residual strength of ancient wooden buildings after long-term load-bearing degradation. At the same time, the domestic prediction of the residual strength of ancient building material degradation is often based on the wood cumulative damage model proposed by American scholar Gerhards. However, this wood cumulative damage model is calibrated based on the results of ten years of long-term test data of commonly used wood in foreign countries. Existing studies have shown that due to the differences in wood species and growth environment that affect the material properties of wood, directly using the parameters in the cumulative damage model proposed by foreign scholars cannot better reflect the DOL effect characteristics of wood used in ancient Chinese buildings. The lack of accurate parameters based on long-term test data of ancient Chinese building materials will cause certain prediction errors. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the above-mentioned related art at least to a certain extent.

[0006] To this end, the purpose of the present invention is to provide a method for predicting the residual strength of ancient wood applied to the vibration table test of ancient building wooden structures, which can improve the universality and accuracy of the prediction of the residual strength of ancient building timber.

[0007] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0008] The embodiment of the present invention provides a method for predicting the residual strength of ancient wood applied to a shaking table test of an ancient building wooden structure, the method comprising:

[0009] S1. Determine the wood species and origin for the prediction of the residual strength of ancient wood according to the test target object;

[0010] S2. According to the determined wood species and origin, new wood of the same species and origin is selected to process the test piece;

[0011] S3. Carry out a wood load continuous effect test on the processed test pieces; the wood load continuous effect test includes a wood bending load continuous effect test along the grain and a wood compression load continuous effect test along the grain;

[0012] S4, calibrating the model parameters in the wood cumulative damage model according to the results of the wood load continuous effect test;

[0013] S5. Based on the wood cumulative damage model after parameter calibration, the residual strength prediction formula of ancient wood is obtained by deduction and solution, and the residual strength of ancient wood is predicted.

[0014] In addition, the ancient wood residual strength prediction method applied to the shaking table test of the ancient building wood structure according to the present invention may also have the following additional technical features:

[0015] In some embodiments, the wood parallel-grain bending load sustained effect test includes three sub-tests, namely, a bending elastic modulus test, a short-term bending strength test, and a long-term bending life test.

[0016] In some of the embodiments, the wood parallel-grain compression load sustained effect test includes three sub-tests, namely a specimen density measurement test, a short-term compressive strength test, and a long-term compressive life test.

[0017] In some of the embodiments, each sub-test has no less than 30 specimens to reduce the discreteness of the data results.

[0018] In some of the embodiments, the flexural modulus test is carried out by four-point chordal loading, with displacement-controlled loading performed at a specific rate. During the loading process, the relative vertical displacement of the specimen at the mid-span and the support is measured to obtain a load-displacement curve, and the data at specific points are taken to calculate the flexural modulus of the specimen.

[0019] In some of the embodiments, the specimens are divided into two groups according to the results of the bending elastic modulus test, and the grouping is based on the principle that the distribution law of the elastic modulus of the two groups is consistent; the two groups of specimens, one group is used as specimens for short-term bending strength test, and the other group is used as specimens for long-term bending life test.

[0020] In some embodiments, the short-term bending strength test adopts a three-point bending chord loading mode, performs displacement-controlled loading at a specific rate until the specimen fails, and takes the load at the time of specimen failure as the maximum load to calculate the short-term bending strength of the specimen;

[0021] The long-term bending life test adopts a three-point bending chord loading mode, and performs trapezoidal cyclic loading with a load-controlled method until the specimen fails, and records the number of cycles the specimen has experienced when it fails; each trapezoidal cycle process includes three processes: loading, holding, and unloading, and each process is linear loading and lasts for a fixed time.

[0022] In some of the embodiments, a density measurement test is performed on a number of specimens, and the specimens are divided into two groups based on the results of the density measurement test, with the principle of consistent density distribution patterns of the two groups of specimens being used as the principle for grouping; of the two groups of specimens, one group is used as specimens for a short-term compressive strength test, and the other group is used as specimens for a long-term compressive life test.

[0023] In some embodiments, the short-term compressive strength test adopts a longitudinal vertical loading mode, performs displacement-controlled loading at a specific rate until the specimen fails, records the load at the time of specimen failure as the maximum load, and calculates the short-term compressive strength of the specimen;

[0024] The long-term compressive life test is carried out along the grain direction of the specimen by load-controlled trapezoidal cyclic loading until the specimen fails, and the number of cycles experienced by the specimen when it fails is recorded; each trapezoidal cycle process includes three processes: loading, holding, and unloading, and each process is linear loading and lasts for a fixed time.

[0025] In some of the embodiments, the content of step S4 includes: respectively matching the distribution data of short-term bending / compressive strength obtained from the wood load duration effect test with the distribution law of long-term bending / compressive failure cycle number, and obtaining the corresponding life of each specimen under the bending / compressive load strength it bears by matching the quantile values ​​as the result of the wood load duration effect test.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] In the embodiment of the present invention, the provided ancient wood residual strength prediction method applied to the shaking table test of the ancient building wood structure can carry out the corresponding wood load continuous effect test according to the different types of wood used in different ancient buildings in my country to correct the model parameters, and has strong applicability for different wood types; can carry out the corresponding wood load continuous effect test according to different wood loading forms (such as bending along the grain and compression along the grain) to correct the model parameters, and has strong applicability for different wood loading forms;

[0028] In the embodiment of the present invention, the ancient wood residual strength prediction method applied to the shaking table test of the ancient building wood structure is provided, which innovatively adds the process of the wood load continuous effect test, and calibrates the relevant prediction parameters according to the test results, thereby obtaining an ancient wood residual strength prediction method that is more suitable for ancient buildings in my country;

[0029] In an embodiment of the present invention, a method for predicting the residual strength of ancient wood applied to a vibration table test of an ancient building wooden structure is provided. In a long-term bending / compression life test, a trapezoidal cyclic loading method is innovatively used to load a small, defect-free wood specimen to obtain the long-term life of the specimen. On this basis, relevant parameters reflecting the continuous effect of wood load can be obtained according to the data.

[0030] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for predicting the residual strength of ancient wood used in a shaking table test of ancient building wood structures disclosed in one embodiment of the present invention;

[0032] Figure 2 A logical relationship diagram of a test on continuous effect of bending load along the grain of wood disclosed in one embodiment of the present invention;

[0033] Figure 3 A schematic diagram of a specimen for a test of a wood parallel-grain bending load sustained effect according to an embodiment of the present invention (unit: mm);

[0034] Figure 4 A load-time curve diagram of a long-term bending test disclosed in one embodiment of the present invention;

[0035] Figure 5 A logical relationship diagram of a test on the continuous effect of a wood longitudinal compression load disclosed in one embodiment of the present invention;

[0036] Figure 6A schematic diagram of a specimen for a test of sustained effect of a compressive load along the grain of wood disclosed in one embodiment of the present invention (unit: mm);

[0037] Figure 7 This is a load-time curve diagram of a long-term compression test disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The embodiments of the present invention are described in detail below through specific embodiments and application scenarios in conjunction with the accompanying drawings.

[0040] See also Figure 1 As shown, in some embodiments of the present invention, a method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure is provided, which mainly includes four steps:

[0041] The first step is to determine the wood species for the prediction of the residual strength of ancient wood according to the wood used in the target object of the ancient building vibration table test; for example, if the target object of the ancient building vibration table test is the Yingxian Wooden Pagoda, then the wood species for the prediction of the residual strength of ancient wood is determined to be the Larix principis-rupprechtii used in the Yingxian Wooden Pagoda;

[0042] The second step is to conduct a wood load duration effect test on the new wood species (e.g. Larix principis-rupprechtii);

[0043] The third step is to calibrate the model parameters in the wood cumulative damage model according to the results of the wood load continuous effect test;

[0044] The fourth step is to theoretically derive the remaining strength prediction formula of ancient trees based on the cumulative damage model with updated parameters.

[0045] The process of the technical solution of the present invention is as follows Figure 1 As shown, the specific implementation method of each step is explained in detail below.

[0046] The first step is to determine the wood type for the prediction of the residual strength of ancient wood according to the target object of the vibration table test of ancient buildings. The methods of literature research and statistics, identification of old wood species, etc. For example, literature research can determine the wood type and origin used in the construction of ancient buildings based on historical records, and identification of old wood species can obtain wood specimens from the target ancient buildings and send them to a third-party agency for inspection to determine the wood type and origin used in the construction.

[0047] The second step is to select new wood of the same type and origin and process it according to the wood species and origin obtained in the previous step to conduct a wood load continuity test. Since wood is an anisotropic material, its load continuity effect is related to the load form. The wood load continuity test can be divided into a wood bending load continuity test and a wood compression load continuity test. Both types of load continuity tests include three small tests. Each small test uses several specimens to reduce the discreteness of the data results. Each small test has a clear logical relationship.

[0048] In some embodiments of the present invention, the wood parallel grain bending load continuous effect test includes: the whole specimen bending elastic modulus test, the short-term bending strength test, and the long-term bending life test, and the logical relationship is as follows: Figure 2 As shown in the figure. The wood specimens for the three small experiments were sawn along the grain of logs, with a size of 20×20×300mm. The specimens did not contain natural defects such as pith, cracks, and knots. At the same time, when sawing the specimens, the 20×20mm cross-sectional grain was kept parallel to the specimen edge in both the tangential and radial directions. Figure 3 The specific implementation method of the wood bending load continuous effect test along the grain is as follows:

[0049] a) The test of continuous effect of bending load along the grain of wood is first carried out on the bending elastic modulus test of all specimens. The bending elastic modulus test is carried out by four-point bending chord loading method, and displacement-controlled loading is carried out at a rate of 2mm / min. During the loading process, the relative vertical displacement of the specimen at the mid-span and the support is measured simultaneously to obtain the load-displacement curve. The corresponding data of the 300N and 700N points are taken to calculate the bending elastic modulus, and the average value is taken after each specimen is measured three times. According to the test results, the bending elastic modulus distribution of all specimens can be obtained. Referring to the bending elastic modulus distribution results, the specimens are divided into two groups according to the principle of consistency of the distribution law of the two groups of elastic moduli. One group is a short-term bending strength test group, and the other group is a long-term bending life test group (for the convenience of distinction, they are respectively called short-term bending group and long-term bending group).

[0050] b) After completing the flexural elastic modulus test of all specimens, the short-term flexural strength test group specimens obtained by the above grouping are tested. The short-term flexural strength test adopts a three-point bending chord loading mode, and displacement-controlled loading is performed at a rate of 6 mm / min until the specimen is destroyed. The load at the time of specimen destruction is recorded as the maximum load, and the short-term flexural strength of the specimen is calculated. The test results of the entire group (short-term flexural strength) are arranged in ascending order to obtain the short-term flexural strength distribution of the flexural short-term group specimens.

[0051] c) After the short-term bending strength test, the long-term bending life test group specimens obtained by the above grouping were tested. The loading mode of the long-term bending test group was three-point bending chord loading, and trapezoidal cyclic loading was performed by load control. A trapezoidal cycle process includes three steps of loading, holding, and unloading. Each step is linear loading and lasts for a fixed time. The loading process of each cycle is exactly the same, and the loading is continuously cycled until the specimen is destroyed. The number of cycles that the specimen has experienced when it is destroyed is recorded, that is, the loading, holding, and unloading times are t respectively. 1 ,t 2 ,t 3 , the loading and unloading process time should be equal, that is, t 1 =t 3 , t 1 ,t 3 The load holding time can be 15s to 60s. 2 It can be 1 to 2 times t 1 After the test, the whole set of test results (cycle numbers) are arranged in ascending order and the distribution law of the number of failure cycles of the long-term bending group specimens is obtained. The specific loading scheme is as follows: Figure 4 As shown (where the peak stress corresponding to the trapezoidal loading can be taken as a certain percentile value of the short-term bending strength distribution obtained above, and the minimum stress of unloading can be taken as 10% of the peak stress).

[0052] In some embodiments of the present invention, the wood longitudinal compression load continuous effect test includes: a whole specimen density measurement test, a short-term compressive strength test, and a long-term compressive life test, and the logical relationship thereof is as follows: Figure 5 The size of the wood specimens in the three small experiments was 20×20×40mm, and the specimens did not contain natural defects such as pith, cracks, and knots. At the same time, when sawing the specimens, the 20×20mm cross-sectional texture was kept parallel to the specimen edge in the tangential and radial directions. Figure 6 The specific implementation method of the wood longitudinal compression load continuous effect test is as follows:

[0053] a) Test on sustained effect of compression load along the wood grain First, the density test of all specimens is carried out (it is sufficient to ensure that the density measurement method of all specimens is consistent). According to the test results, the density distribution of all specimens can be obtained. Based on the principle of consistency of the density distribution law of the two groups, the specimens are divided into two groups, one for short-term compressive strength test and the other for long-term compressive life test (for the convenience of distinction, they are called short-term compressive group and long-term compressive group respectively).

[0054] b) After completing the density measurement test of all specimens, the short-term compressive strength test specimens obtained by the above grouping are tested. The short-term compressive strength test adopts the vertical loading mode along the grain, and the displacement-controlled loading is carried out at a rate of 1mm / min until the specimen is destroyed. The load at the time of specimen destruction is recorded as the maximum load, and the short-term compressive strength of the specimen is calculated. The test results (short-term compressive strength) are arranged in ascending order to obtain the short-term compressive strength distribution of the compressive short-term group specimens.

[0055] c) After the short-term compressive strength test, the long-term compressive life test specimens obtained by the above grouping are tested. The long-term compressive life test is vertically loaded along the grain direction of the specimens, and the loading method is load-controlled trapezoidal cyclic loading. A trapezoidal cycle process includes three steps: loading, holding, and unloading. Each step is linear loading and lasts for a fixed time; the loading process of each cycle is exactly the same, and the loading is continuously cycled until the specimen is destroyed, and the number of cycles that the specimen has experienced when it is destroyed is recorded, that is, the loading, holding, and unloading times are t respectively. 1 ,t 2 ,t 3 , the loading and unloading process time should be equal, that is, t 1 =t 3 , t 1 ,t 3 The load holding time can be 15s to 60s. 2 It can be 1 to 2 times t 1 After the test, the whole set of test results (cycle numbers) are arranged in ascending order and the distribution law of the number of failure cycles of the long-term compressive test specimens is obtained. The specific loading scheme is as follows: Figure 7 As shown (wherein the peak stress corresponding to the trapezoidal loading can be taken as a certain percentile value of the short-term compressive strength distribution obtained above, and the minimum stress of unloading can be taken as 10% of the peak stress).

[0056] In the above embodiment, the peak stress corresponding to the trapezoidal loading in the long-term bending life test group can be selected from the 5th to 30th corresponding values ​​of the short-term bending strength distribution, and the peak stress corresponding to the trapezoidal loading in the long-term compressive life test group can be selected from the 5th to 35th corresponding values ​​of the short-term compressive strength distribution. The minimum stress during trapezoidal unloading in the long-term life test group can be 10% of the peak stress of the trapezoidal loading to avoid the influence of stress redistribution caused by unloading.

[0057] In one embodiment of the present invention, the total number of specimens for the bending / compression load sustained effect test should be no less than 30. The more specimens there are, the less discrete the test results are. When grouping in the bending / compression load sustained effect test, ensure that the number of specimens included in the short-term experimental group and the long-term experimental group is the same. The moisture content of the specimen should be kept unchanged or slightly changed throughout the bending / compression load sustained effect test as much as possible. In some embodiments of the present invention, detecting deformation by strain gauges or other means can help better determine the failure time of the specimen in the long-term bending / compression life test.

[0058] The third step is to calibrate the model parameters in the wood cumulative damage model according to the results of the wood load continuous effect test. The short-term bending / compression strength distribution obtained for compression and bending is matched one by one with the distribution law of the long-term bending / compression failure cycle number, and the results of the wood load continuous effect test are obtained by the equal quantile matching method, that is, the corresponding life of each bending / compression specimen under the bending / compression load strength it bears in the test. The test results of the continuous effect of wood bending load along the grain and the continuous effect of wood bending load along the grain are respectively brought into the wood cumulative damage model, and the mathematical tool least squares method can be used to calibrate and obtain updated wood cumulative damage model parameters suitable for the continuous effect of wood bending load along the grain and the continuous effect of wood compression load along the grain.

[0059] The above wood cumulative damage model uses the concept of damage amount to describe the damage of wood materials under any load history, which can be expressed as follows:

[0060]

[0061] In the formula, α is the damage state variable, where α = 0 and α = 1 represent the undamaged state and failure state respectively, and t represents the untested specimen. a and b are constants, σ(t) is the applied stress history, and σ s is the short-term strength of wood. Parameters a and b are parameters related to wood properties and are the objects calibrated in the present invention.

[0062] The fourth step is to obtain the residual strength prediction formula of ancient wood by deducing and solving the cumulative damage model with updated parameters.

[0063] The prediction formula of the remaining strength of ancient wood can be expressed as:

[0064]

[0065] Where σ is the residual strength of wood, σ s is the short-term strength of wood, α represents the damage state variable, which can be obtained by integral calculation of the above-mentioned wood cumulative damage model. Parameter b has the same meaning as in the above-mentioned wood cumulative damage model, and is obtained by experimental calibration using the method of the present invention.

[0066] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0067] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure, characterized in that: The method comprises: S1. Determine the wood species and origin for the prediction of the residual strength of ancient wood according to the test target object; S2. According to the determined wood species and origin, new wood of the same species and origin is selected to process the test piece; S3. Carry out a wood load continuous effect test on the processed test pieces; the wood load continuous effect test includes a wood bending load continuous effect test along the grain and a wood compression load continuous effect test along the grain; S4, calibrating the model parameters in the wood cumulative damage model according to the results of the wood load continuous effect test; S5. Based on the wood cumulative damage model after parameter calibration, the residual strength prediction formula of ancient wood is obtained by deduction and solution, and the residual strength of ancient wood is predicted.

2. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to claim 1 is characterized in that: The test on sustained effect of bending load along the grain of wood includes three sub-tests, namely, a bending elastic modulus test, a short-term bending strength test and a long-term bending life test.

3. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to claim 1 is characterized in that: The test on sustained effect of compressive load along the wood grain includes three sub-tests, namely, a specimen density measurement test, a short-term compressive strength test and a long-term compressive life test.

4. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to any one of claims 2-3, characterized in that: Each sub-test has no less than 30 specimens to reduce the discreteness of the data results.

5. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to claim 2 is characterized in that: The flexural elastic modulus test is carried out by four-point bending chord loading, and displacement-controlled loading is performed at a specific rate. During the loading process, the relative vertical displacements of the specimen at the mid-span and the support are measured to obtain a load-displacement curve, and the data at specific points are taken to calculate the flexural elastic modulus of the specimen.

6. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to claim 2 is characterized in that: According to the results of the bending elastic modulus test, the specimens were divided into two groups, and the grouping was based on the principle that the distribution law of the elastic modulus of the two groups was consistent; the two groups of specimens, one group was used as specimens for short-term bending strength test, and the other group was used as specimens for long-term bending life test.

7. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to claim 6 is characterized in that: The short-term bending strength test adopts a three-point bending chord loading mode, and performs displacement-controlled loading at a specific rate until the specimen fails. The load at the time of specimen failure is taken as the maximum load, and the short-term bending strength of the specimen is calculated; The long-term bending life test adopts a three-point bending chord loading mode, and performs trapezoidal cyclic loading with a load-controlled method until the specimen fails, and records the number of cycles the specimen has experienced when it fails; each trapezoidal cycle process includes three processes: loading, holding, and unloading, and each process is linear loading and lasts for a fixed time.

8. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to claim 3 is characterized in that: A density measurement test was carried out on a number of specimens. According to the results of the density measurement test, the specimens were divided into two groups. The grouping was based on the principle that the density distribution patterns of the two groups of specimens were consistent. Among the two groups of specimens, one group was used as specimens for short-term compressive strength test, and the other group was used as specimens for long-term compressive life test.

9. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to claim 8, characterized in that: The short-term compressive strength test adopts the vertical loading mode along the grain, and performs displacement-controlled loading at a specific rate until the specimen fails. The load at the time of specimen failure is recorded as the maximum load, and the short-term compressive strength of the specimen is calculated; The long-term compressive life test is carried out along the grain direction of the specimen by load-controlled trapezoidal cyclic loading until the specimen fails, and the number of cycles experienced by the specimen when it fails is recorded; each trapezoidal cycle process includes three processes: loading, holding, and unloading, and each process is linear loading and lasts for a fixed time.

10. The method for predicting the residual strength of ancient wood applied to the shaking table test of ancient building wood structure according to claim 4, characterized in that: The content of step S4 includes: respectively matching the distribution data of short-term bending / compressive strength obtained from the wood load continuous effect test with the distribution law of long-term bending / compressive failure cycle number, and obtaining the corresponding life of each specimen under the bending / compressive load strength it bears by equal quantile matching, as the result of the wood load continuous effect test.

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