A structural simulation analysis method for building jacking

Abstract

The present invention relates to a structural simulation analysis method for building jacking, comprising: establishing a finite element model of a building structure; applying statically determinate boundary conditions at the bottom of each structural column, and performing loading calculation on the finite element model, wherein the statically determinate boundary conditions are set as boundary conditions for consolidation of all degrees of freedom; based on the result of the loading calculation, selecting key components in the finite element model; modifying the boundary conditions applied at the bottom of each structural column to jacking boundary conditions, re-loading and calculating the finite element model, accumulating and cyclically calculating N times, and setting the jacking boundary conditions as boundary conditions for consolidating the torsional degrees of freedom at the bottom of each structural column; statistically calculating the stress magnitude and percentage of change of key components in each calculation; based on the statistical results, screening the corresponding boundary conditions, and analyzing the magnitude and distribution of uneven jacking force in the boundary conditions. The present invention can analyze structural weakness, dangerous parts, component stress, and the like caused by jacking force errors during the jacking process.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a structural simulation analysis method applied to building jacking. Background Art

[0002] In the field of construction, it is necessary to lift existing buildings. Building lifting refers to the necessary reinforcement of existing buildings, changing their force transmission path according to the underpinning theory, so that the building is separated from the lower structure at an appropriate position to form a movable whole; the building is lifted to a new height through a power equipment system such as a lifting jack, and then connected after it is in place.

[0003] In the actual jacking process, it is difficult to achieve zero error output of the jacking force. How to ensure that the random jacking force error (including the randomness of the jacking force error size and the randomness of the position distribution) will not affect the structural safety during the jacking process is worthy of study. Summary of the invention

[0004] The present invention provides a structural simulation analysis method applied to building jacking to solve the above technical problems.

[0005] In order to solve the above technical problems, the present invention provides a structural simulation analysis method applied to building jacking, comprising the following steps:

[0006] Establish finite element models of building structures;

[0007] Applying statically determinate boundary conditions at the bottom of each structural column and performing loading calculation on the finite element model, wherein the statically determinate boundary conditions are set as boundary conditions of full-degree-of-freedom consolidation;

[0008] Based on the results of the loading calculation, key components in the finite element model are selected;

[0009] The boundary conditions applied at the bottom of each structural column are modified to jacking boundary conditions, and the finite element model is loaded and calculated again, and the cumulative cycle calculation is performed N times. The jacking boundary conditions are set to consolidate the torsional freedom degree at the bottom of each structural column, and the boundary conditions of the three-axis translational freedom degree in the three-dimensional coordinate system are simulated by three uniaxial springs;

[0010] Counting the stress magnitude and change percentage of the key components in each calculation;

[0011] Based on the statistical results, the corresponding boundary conditions are screened, and the size and distribution of the uneven lifting force in the boundary conditions are analyzed.

[0012] Preferably, the key component is selected based on the magnitude of stress and / or the degree of weakness of each structural column in the finite element model.

[0013] Preferably, the number of cycles N can make the statistical result conform to the law of large numbers.

[0014] Preferably, the method for screening corresponding boundary conditions based on statistical results includes: screening out from the statistical results the situations where the absolute value of stress of the key component is greater than a first threshold and / or the percentage of change is greater than a second threshold, and then obtaining boundary conditions corresponding to the above situations.

[0015] Compared with the prior art, the structural simulation analysis method for building jacking provided by the present invention has the following advantages:

[0016] The present invention innovatively proposes a method for structural simulation analysis during the jacking process, which can be used to analyze structural weaknesses, dangerous parts, component stress conditions, and corresponding jacking force error distribution conditions caused by jacking force errors during the jacking process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flowchart of a structural simulation analysis method applied to building jacking in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to describe the technical solution of the above invention in more detail, specific embodiments are listed below to demonstrate the technical effect; it should be emphasized that these embodiments are used to illustrate the present invention but are not limited to the scope of the present invention.

[0019] The structural simulation analysis method for building jacking provided by the present invention is as follows: Figure 1 As shown, the following steps are included:

[0020] Create a finite element model of the building structure.

[0021] A statically determinate boundary condition is applied to the bottom of each structural column, and a loading calculation is performed on the finite element model. The statically determinate boundary condition is set as a boundary condition of full-degree-of-freedom consolidation, that is, a boundary condition in a statically determinate state.

[0022] Based on the results of the loading calculation, the key components in the finite element model are selected. Specifically, the key components are selected based on the stress size and / or weakness of each structural column in the finite element model. In this embodiment, components with larger stress and / or in weak structural parts in the finite element model are selected as key components.

[0023] The boundary conditions applied at the bottom of each structural column are modified to jacking boundary conditions, and the finite element model is reloaded and calculated, and the cumulative cycle calculation is N times. The jacking boundary conditions are set to consolidate the torsional freedom at the bottom of each structural column, and use three uniaxial springs to simulate the boundary conditions of the three-axis (X-axis, Y-axis and Z-axis) translational freedom in the three-dimensional coordinate system. Since the building structure in the jacking process is no longer suitable for the boundary conditions of full-degree-of-freedom consolidation, the present application modifies the boundary conditions applied at the bottom of each structural column to jacking boundary conditions to better simulate the boundary conditions of the building structure in the jacking process.

[0024] The stress magnitude and change percentage of the key components in each calculation are statistically calculated.

[0025] Based on the statistical results, the corresponding boundary conditions are screened, and the magnitude and distribution of the uneven lifting force in the boundary conditions are analyzed. Specifically, the method for screening the corresponding boundary conditions based on the statistical results includes: screening out the situations where the absolute value of the stress of the key component is greater than the first threshold value and / or the percentage of change is greater than the second threshold value from the statistical results, and then obtaining the boundary conditions corresponding to the above situations, and analyzing the magnitude and distribution of the uneven lifting force in these boundary conditions. Finally, the rules are summarized according to the statistical results to find out the most dangerous situation that may occur during the lifting process of the building structure due to the lifting force error.

[0026] The analysis method provided by the present invention can be implemented based on finite element analysis software, program batch execution, and result batch storage commands.

[0027] The present invention innovatively proposes a method for structural simulation analysis during the jacking process, which can be used to analyze structural weaknesses, dangerous parts, component stress conditions, and corresponding jacking force error distribution conditions caused by jacking force errors during the jacking process.

[0028] Specifically, the method of using three uniaxial springs to simulate the three-axis translational degrees of freedom in a three-dimensional coordinate system includes: the method of setting the spring stiffness in the horizontal direction is: the shear force when each structural column overturns / the maximum horizontal drift allowed; the method of setting the spring stiffness in the vertical direction is: the resultant force that produces the jacking acceleration / the maximum allowed asynchronous jacking displacement difference. In addition, it is necessary to apply a 100% accurate standard jacking force that is in the opposite direction (i.e., equal in magnitude and opposite in direction) to the "axial force of each column when the structure is in a static state" at the bottom of each structural column. The present invention proposes an accurate method for setting the boundary conditions of a numerical model that can be used for structural simulation analysis during the jacking process.

[0029] In addition, since the lifting acceleration is very small, generally 0.01g~0.05g (g is the acceleration of gravity), the structural dynamic effect it produces is very small and can be ignored. Therefore, based on the above-mentioned lifting boundary condition setting method, the lifting force errors in the actual lifting process are considered, and the boundary condition setting of the structural simulation analysis in the lifting process is completed.

[0030] Specifically, suppose that at a certain structural column p, the actual lifting force at the bottom of the structural column is N p The standard lifting force at the bottom of the structural column, that is, the 100% accurate lifting force in the opposite direction of the "axial force of the column when the structure is in a static state" is N p0 It can be assumed that the actual lifting force N of the structural column considering the lifting force error is p Subject to a certain probability distribution, for example: N p ~N(N p0 ,a), that is, the actual lifting force N at the structural column p p Subject to the standard lifting force N of the structural column with the mean value p0 , a normal distribution with standard deviation a. The standard deviation a can be a constant or N p0 The value of a should be consistent with the possible error of the lifting force in actual situation.

[0031] Preferably, the number of cycles N should be large enough to make the statistical results conform to the law of large numbers. Specifically, in each cycle calculation process, a certain structural column is selected to track the change and convergence of the mean and standard deviation of the lifting force set at the bottom of the structural column. p ~N(N p0 ,a) Take an example: when the lifting force set at the structural column p gradually converges to N in the cumulative cycle calculation, p0 , the standard deviation gradually converges to a, and it can be considered that the value of N is large enough to make the statistical results conform to the law of large numbers and reflect regularity. Of course, the specific value of N also depends on factors such as the need for convergence accuracy and the time cost consumed by the cyclic calculation operation.

[0032] The above method can reflect the randomness of the jacking error, and while considering the random jacking error, analyze the structural weaknesses, dangerous parts, and component stress of the building structure during the jacking process.

[0033] In summary, the structural simulation analysis method for building jacking provided by the present invention includes the following steps: establishing a finite element model of the building structure; applying statically determinate boundary conditions at the bottom of each structural column, and performing loading calculation on the finite element model, wherein the statically determinate boundary conditions are set as boundary conditions for full degree of freedom consolidation; based on the result of the loading calculation, selecting key components in the finite element model; modifying the boundary conditions applied at the bottom of each structural column to jacking boundary conditions, re-loading and calculating the finite element model, accumulating and cyclically calculating N times, wherein the jacking boundary conditions are set to consolidate the torsional degree of freedom at the bottom of each structural column, and simulating the boundary conditions of the three-axis translational degree of freedom in the three-dimensional coordinate system with three uniaxial springs; counting the stress magnitude and percentage change of the key components in each calculation; based on the statistical results, screening the corresponding boundary conditions, and analyzing the magnitude and distribution of the uneven jacking force in the boundary conditions. Based on the probability analysis method, the present invention innovatively proposes a method for structural simulation analysis in the jacking process, which can be used to analyze the structural weakness, dangerous parts, component stress conditions, and corresponding jacking force error distribution caused by jacking force errors in the jacking process.

[0034] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A structural simulation analysis method applied to building jacking, characterized in that: The steps include: Establish finite element models of building structures; Applying statically determinate boundary conditions at the bottom of each structural column and performing loading calculation on the finite element model, wherein the statically determinate boundary conditions are set as boundary conditions of full-degree-of-freedom consolidation; Based on the result of the loading calculation, the key components in the finite element model are selected, and the key components are selected based on the magnitude of the stress and / or the degree of weakness of each structural column in the finite element model; The boundary conditions applied at the bottom of each structural column are modified to jacking boundary conditions, and the finite element model is loaded and calculated again, and the cumulative cycle calculation is performed N times. The jacking boundary conditions are set to consolidate the torsional freedom degree at the bottom of each structural column, and the boundary conditions of the three-axis translational freedom degree in the three-dimensional coordinate system are simulated by three uniaxial springs; Counting the stress magnitude and change percentage of the key components in each calculation; Based on the statistical results, the corresponding boundary conditions are screened, including: screening out from the statistical results the situations where the absolute value of the stress of the key component is greater than a first threshold value and / or the percentage of change is greater than a second threshold value, and then obtaining the boundary conditions corresponding to the above situations; analyzing the size and distribution of the uneven lifting force in the boundary conditions.

2. The structural simulation analysis method for building jacking according to claim 1, characterized in that: The number of cycles N can make the statistical results conform to the law of large numbers.

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