Method for calculating high-rise rigidity of concrete-filled steel tube structure by considering void defect

Abstract

The invention provides a method for calculating the high-rise rigidity of a concrete-filled steel tube structure by considering a void defect, which comprises the following steps of: S1, detecting a to-be-detected concrete-filled steel tube structure, identifying a void phenomenon between concrete and a steel tube, and obtaining a void area and void parameters; and S2, according to a detection result, the rigidity and a correction coefficient beta of the concrete before and after disengagement are calculated, the overall rigidity of the structure is corrected through a correction formula k = ks + beta kc, ks is the rigidity of the steel pipe, kc is the rigidity of the concrete, and the overall correction rigidity k of the structure is calculated and obtained, namely the high-rise rigidity of the concrete-filled steel pipe structure considering the concrete disengagement. According to the technical scheme, the safety, the design precision and the maintenance efficiency of the structure are remarkably improved by correcting rigidity calculation of the concrete filled steel tube structure, and the method is suitable for high-rise buildings and large projects under complex working conditions.

Description

Technical Field

[0001] The invention belongs to the field of building structure engineering, and in particular relates to a method for calculating the high-rise stiffness of a steel tube concrete structure taking into account void defects. Background Art

[0002] Steel tube concrete structures have been widely used in high-rise and super-high-rise buildings due to their high bearing capacity and good seismic performance. In actual engineering, common design and research work is often obtained under the premise of ideal bonding performance between concrete and steel tubes, that is, the concrete is completely filled without any gaps. However, this calculation method cannot fully reflect the stress conditions of the actual structure, which can easily cause design errors and structural hidden dangers. Specifically, with the extension of service time or the influence of external environment (such as temperature changes, vibrations, material aging, etc.), there may be a phenomenon of voids between concrete and steel tubes, resulting in the inability of concrete to fully participate in the structural load-bearing, thereby affecting the stiffness and safety of the overall structure. Summary of the invention

[0003] In view of the above technical problems, the present invention discloses a method for calculating the stiffness of a high-rise steel tube concrete structure taking into account the void defect, so as to quantitatively analyze the influence of concrete voids on the structural stiffness in a high-rise steel tube concrete structure. By considering the actual bearing conditions of concrete, a more accurate stiffness calculation formula is provided, thereby improving the safety and reliability of high-rise buildings under complex loads and long-term service conditions.

[0004] To this end, the technical solution adopted by the present invention is:

[0005] A method for calculating the stiffness of a high-rise steel tube concrete structure considering void defects comprises the following steps:

[0006] Step S1, testing the steel tube concrete structure to be tested, identifying the voids between the concrete and the steel tube, and obtaining the void area and void parameters;

[0007] Step S2, according to the detection results, the stiffness and correction coefficient β of the concrete before and after the degassing are calculated, and the overall stiffness of the structure is corrected using the correction formula (1), and the corrected stiffness k of the overall structure is calculated, which is the high-rise stiffness of the steel tube concrete structure considering the degassing of the concrete;

[0008] k=k s +βk c (1), where k s is the steel tube stiffness, k c is the stiffness of concrete.

[0009] By adopting this technical solution, the concrete void phenomenon is first identified, and then the high-rise stiffness of the steel tube concrete structure is corrected and calculated, providing comprehensive technical support to ensure the safety and reliability of the structure.

[0010] As a further improvement of the present invention, in step S1, ultrasonic detection, X-ray scanning or CT scanning detection equipment is used to scan the steel tube concrete structure to obtain the actual situation of the internal structure, collect the gap data between the concrete and the steel tube, analyze the collected gap data, confirm the area and range of concrete voids, record the void position, and calculate the void area.

[0011] As a further improvement of the present invention, in step S1, infrared thermal imaging technology or electromagnetic wave detection is used to perform non-contact detection on the steel tube concrete structure to identify the void area, and a vibration sensor is used to monitor the vibration difference between the concrete and the steel tube to infer the position and range of the void area.

[0012] As a further improvement of the present invention, in step S1, the emptying parameters include the emptying area A e ;

[0013] Step S2 includes: according to the detected empty area A e The total cross-sectional area A when the steel pipe is filled with concrete c , according to formula (2), the air gap correction coefficient is calculated, β = 1-A e / A c (2).

[0014] As a further improvement of the present invention, in step S1, the voiding parameter includes the relative displacement between the concrete and the steel pipe.

[0015] As a further improvement of the present invention, in step S2, a nonlinear correction coefficient is used as the correction coefficient in consideration of the nonlinear stress behavior of concrete.

[0016] As a further improvement of the present invention, the method for calculating the high-rise stiffness of the steel tube concrete structure considering the void defect also includes step S3: according to the result obtained in step S2, the stiffness change caused by the void is input into the finite element analysis software to establish the steel tube concrete structure model in the void and non-void state; vertical load, horizontal load and dynamic load are applied to the model to simulate the stress condition of the building under various actual working conditions; the displacement, stress distribution and overall stiffness under the two models are compared to verify the accuracy of the void correction coefficient; according to the simulation results, the stiffness correction model is further optimized to ensure that the calculation results are consistent with the stress state of the actual structure. Among them, the optimized stiffness correction model includes: the actual displacement can be obtained by laying sensors in the actual project, and the results in the model are compared with the results obtained by monitoring. If there is a certain gap between the two, further analysis is performed according to the actual monitoring results to find the cause and modify and improve the finite element model.

[0017] The present invention also discloses a method for evaluating the health status of a building structure, that is, the application of the above-mentioned method for calculating the high-rise stiffness of a steel tube concrete structure considering the void defect, comprising: evaluating the overall structural health status of the building according to the stiffness result obtained by the above-mentioned method for calculating the high-rise stiffness of a steel tube concrete structure considering the void defect, and judging whether structural reinforcement is needed. The reinforcement measures include adding support components, filling the void area, or adding an external reinforcement structure.

[0018] The present invention also discloses a health monitoring method for building structures, that is, the application of the method for calculating the high-rise stiffness of steel tube concrete structures considering void defects as described above, comprising: using optical fiber sensors to perform real-time monitoring based on the stiffness results obtained by the method for calculating the high-rise stiffness of steel tube concrete structures considering void defects as described above, tracking the expansion of the void area and the change in stiffness, performing data collection, and correcting the stiffness model; regularly scanning the exterior of the high-rise building through unmanned aerial vehicle detection equipment to obtain the building stress and deformation information, and combining it with the void area model identified in step S1 to perform health monitoring.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] By adopting the technical solution of the present invention, the safety, design accuracy and maintenance efficiency of the structure are significantly improved by accurately identifying the concrete void area and correcting the stiffness calculation of the steel tube concrete structure. This method is suitable for high-rise buildings and large projects under complex working conditions, can optimize the design, save costs, and enhance the health monitoring capability of the structure, providing a scientific basis for engineering construction and long-term maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1It is a flow chart of a method for calculating high-rise stiffness of a steel tube concrete structure taking into account void defects according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described in further detail below.

[0023] A calculation method for the stiffness of high-rise concrete-filled steel tube structures considering void defects, such as Figure 1 As shown, the following steps are included:

[0024] Step S1, void identification and detection: Use advanced detection methods to monitor the steel tube concrete structure and identify the void between the concrete and the steel tube;

[0025] Step S2, stiffness calculation and correction: according to the test results, the stiffness of the concrete before and after the voiding is calculated, and the overall stiffness of the structure is corrected using a correction formula;

[0026] Step S3, numerical simulation and verification: numerical simulation is performed through finite element analysis to analyze the influence of concrete voids on the overall structural stiffness;

[0027] Step S4, engineering application and optimization design: combining the void identification results and the modified stiffness model, the design and health status of the building structure are evaluated and optimized.

[0028] The step S1 specifically includes:

[0029] Testing preparation: Select appropriate testing equipment, such as ultrasonic detection, X-ray scanning or CT scanning, to scan the concrete-filled steel tube structure to obtain the actual situation of the internal structure;

[0030] Data collection: Conduct a comprehensive structural scan to collect data on the gap between concrete and steel pipes;

[0031] Void identification: Analyze the test data, confirm the area and scope of concrete voids, and record the location and area of ​​voids.

[0032] The step S2 is specifically as follows:

[0033] Establish an ideal structural model: Assuming that the concrete is fully filled, calculate the stiffness of the steel tube concrete structure without voids k0 = k s +k c , where k s is the steel tube stiffness, k c is the concrete stiffness;

[0034] Calculate the void coefficient: Based on the detected void area A e The total cross-sectional area A when the steel pipe is filled with concrete cCalculate the void correction factor: β = 1-A e / A c ;

[0035] Corrected stiffness formula: Use correction factor k = k s +βk c .

[0036] The step S3 specifically includes:

[0037] Construct finite element model: input the stiffness change caused by voids into finite element analysis software to establish concrete-filled steel tube structure models with and without voids;

[0038] Load application: Apply vertical load, horizontal load and dynamic load to the model to simulate the stress of the building under various actual working conditions;

[0039] Result comparison: Compare the displacement, stress distribution and overall stiffness of the two models to verify the accuracy of the void correction coefficient;

[0040] Optimize model: Based on the simulation results, further optimize the stiffness correction model to ensure that the calculation results are consistent with the stress state of the actual structure.

[0041] The step S4 specifically includes:

[0042] Health status assessment: Based on the corrected stiffness calculation results, the overall structural health status of the building is assessed to determine whether structural reinforcement is needed;

[0043] Design optimization: In new construction projects, consider the possibility of concrete voids and reserve safety margins in advance during design. Ensure the safety of the building in the event of voids by optimizing the size of structural components and material selection;

[0044] Reinforcement plan: If the voids cause a significant reduction in building stiffness, reinforcement measures can be proposed based on the calculation results, such as adding supporting components, filling the void areas, or adding external reinforcement structures;

[0045] Real-time monitoring and adjustment: During the long-term service life of the building, the health monitoring system is combined to evaluate the stiffness changes of the structure in real time, and dynamically adjust the design and maintenance plans based on the new test data.

[0046] The above technical solution aims at concrete voids and proposes a void correction coefficient β for correcting the calculation of the overall structural stiffness to ensure the applicability of the method under different void conditions.

[0047] Furthermore, the means of identifying the void phenomenon can use infrared thermal imaging technology or electromagnetic wave detection instead of ultrasound or X-rays to perform non-contact detection and identify the void area; use vibration sensors to monitor the vibration difference between concrete and steel pipes to infer the location and range of the void area.

[0048] Furthermore, based on the relative displacement of concrete and steel pipe, a displacement correction factor for the size and position of the void area can be introduced as an alternative stiffness correction factor β, using k = k s +βk c Correct the overall stiffness of the structure.

[0049] Furthermore, considering the nonlinear stress behavior of concrete, a nonlinear correction coefficient is introduced to more accurately describe the influence of the void area on the overall structural stiffness.

[0050] This embodiment also discloses a method for evaluating the health status of a building structure, including: evaluating the overall structural health status of the building according to the stiffness result obtained by the method for calculating the high-rise stiffness of a steel tube concrete structure taking into account the void defect as described above, and determining whether structural reinforcement is required. The reinforcement measures include adding support components, filling void areas, or adding external reinforcement structures.

[0051] This embodiment also discloses a health monitoring method for a building structure, including: using a fiber optic sensor to perform real-time monitoring based on the stiffness result obtained by the method for calculating the high-rise stiffness of a steel tube concrete structure taking into account void defects as described above, tracking the expansion of the void area and the change in stiffness, performing data collection, and correcting the stiffness model; and regularly scanning the exterior of the high-rise building with an unmanned aerial vehicle detection device to obtain the building's stress and deformation information, and combining it with the void area model for health monitoring.

[0052] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for calculating the high-rise stiffness of a steel tube concrete structure taking into account void defects, characterized in that: The steps include: Step S1, testing the steel tube concrete structure to be tested, identifying the voids between the concrete and the steel tube, and obtaining the void area and void parameters; Step S2, according to the detection results, the stiffness and correction coefficient β of the concrete before and after the degassing are calculated, and the overall stiffness of the structure is corrected using the correction formula (1), and the corrected stiffness k of the overall structure is calculated, which is the high-rise stiffness of the steel tube concrete structure considering the degassing of the concrete; k=k s +βk c (1), where k s is the steel tube stiffness, k c is the stiffness of concrete.

2. The method for calculating the high-rise stiffness of a steel tube concrete structure considering void defects according to claim 1 is characterized in that: In step S1, ultrasonic detection, X-ray scanning or CT scanning detection equipment is used to scan the steel tube concrete structure to obtain the actual situation of the internal structure, collect the gap data between the concrete and the steel tube, analyze the collected gap data, confirm the area and range of the concrete void, record the void position, and calculate the void area.

3. The method for calculating the high-rise stiffness of a steel tube concrete structure considering void defects according to claim 1 is characterized in that: In step S1, infrared thermal imaging technology or electromagnetic wave detection is used to perform non-contact detection on the steel tube concrete structure to identify the void area, and a vibration sensor is used to monitor the vibration difference between the concrete and the steel tube to infer the location and range of the void area.

4. The method for calculating the high-rise stiffness of a steel tube concrete structure considering void defects according to claim 2 is characterized by: In step S1, the emptying parameters include the emptying area A e ; Step S2 includes: according to the detected empty area A e The total cross-sectional area A when the steel pipe is filled with concrete c , according to formula (2), the air gap correction coefficient is calculated, β = 1-A e / A c (2).

5. The method for calculating the high-rise stiffness of a steel tube concrete structure considering void defects according to claim 2 is characterized in that: In step S1, the voiding parameter includes the relative displacement between the concrete and the steel pipe. In step S2, a nonlinear correction coefficient is used as a correction coefficient according to the nonlinear stress behavior of the concrete.

6. The method for calculating the high-rise stiffness of a steel tube concrete structure considering void defects according to claim 4 or 5, characterized in that: The method also includes step S3: according to the result obtained in step S2, the stiffness change caused by the voiding is input into the finite element analysis software to establish the steel tube concrete structure model in the voiding state and the non-voiding state; vertical load, horizontal load and dynamic load are applied to the model to simulate the stress condition of the building under various actual working conditions; the displacement, stress distribution and overall stiffness under the two models are compared to verify the accuracy of the voiding correction coefficient; according to the simulation results, the stiffness correction model is further optimized.

7. A method for assessing the health status of a building structure, characterized in that: The stiffness result obtained by the method for calculating the high-rise stiffness of a steel tube concrete structure taking into account void defects according to any one of claims 1 to 6 is used to evaluate the overall structural health of the building and determine whether structural reinforcement is required.

8. A method for health monitoring of a building structure, characterized in that: The stiffness result obtained by the method for calculating the high-rise stiffness of a steel tube concrete structure considering void defects according to any one of claims 1 to 6 is monitored in real time using an optical fiber sensor to track the expansion of the void area and the change in stiffness, collect data, and correct the stiffness model; The exterior of high-rise buildings is scanned regularly by drone-mounted detection equipment to obtain building stress and deformation information, which is then combined with the void area model identified in step S1 to perform health monitoring.

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