Building structure test detection method

Abstract

The invention discloses a building structure test detection method, which comprises a resiliometer, a vibration pickup and a dynamic tester, and specifically comprises the following steps: step 1, a test point is positioned in the middle of a structure, in order to facilitate test, a beam component excitation point and the vibration pickup are positioned in the middle of the bottom of a beam, and a column component is positioned in the middle of the bottom of the beam; the excitation point and the vibration pickup are located in the longitudinal or transverse middle position; secondly, a tool steel cushion block with the impact surface hardness being HRC60 + / -2 is placed at an excitation point; 3, for the beam type component, a rebound instrument with the nominal energy of 2.207 J is adopted for a vibration exciter, and upward impact is conducted; and 4, for the column component, the dynamic stiffness of the component is tested to achieve detection and evaluation of material properties and boundary support conditions, the excitation mode is transient excitation, dynamic stiffness parameters, namely the vibration speed and the resonance frequency, are obtained through calculation and analysis of a vibration curve, and meanwhile, the vibration speed and the resonance frequency are calculated. And the curve of each frequency band of the obtained vibration curve can be used as an information source for analyzing the structural member for different purposes.

Description

Technical Field

[0001] The present invention relates to the field of building technology, and particularly to a method for testing and detecting building structures. Background Art

[0002] On-site testing of building structures generally relies on the mechanical properties of structural materials. For reinforced concrete structures, it mainly focuses on the strength testing of concrete and steel bars in individual components. There is currently no effective, fast, and simple testing and evaluation method for the changes in structural performance after long-term use or damage caused by external factors. Based on the fact that the stiffness of a structural component is related to the material properties, geometric shape, boundary support conditions, and the form of external force acting on it, in an existing structure, the geometric shape remains fixed. If the form of external force remains unchanged, but the material properties and boundary support conditions of the component change, the stiffness of the component will also change accordingly. Furthermore, if the boundary support conditions remain unchanged and the material properties change, the stiffness of the component will also change.

[0003] However, a lot of equipment is required to measure the static stiffness of components on-site, and the operation is very difficult and the efficiency is extremely low, making it difficult to implement. The present invention uses the measurement of the dynamic stiffness of components to achieve the detection and evaluation of material properties and boundary support conditions. The excitation method is transient excitation, and the dynamic stiffness parameters, namely vibration velocity and resonance frequency, are obtained through the calculation and analysis of the vibration curve. At the same time, the curves in each frequency band of the obtained vibration curve can be used as the information source for analyzing structural components for different purposes. Summary of the Invention

[0004] The present invention discloses a method for testing and detecting building structures, aiming to solve the technical problems of difficult operation and low efficiency mentioned in the background art.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for testing and detecting building structures, including a rebound hammer, a vibration pickup, and a dynamic tester, specifically including the following steps:

[0007] Step 1: The test points are located in the middle of the structure. For the convenience of testing, for beam-like components, the excitation point and the vibration pickup are both located at the middle position at the bottom of the beam; for column-like components, the excitation point and the vibration pickup are both located at the longitudinal or transverse middle position.

[0008] Step 2: Place a tool steel pad with a hardness of HRC60±2 on the impact surface at the excitation point.

[0009] Step 3: For beam-like components, use a rebound hammer with a nominal energy of 2.207 J as the exciter and impact upward.

[0010] Step 4: For column-like components, according to the size of the component, use rebound hammers with nominal energies of 2.207 J, 4.500 J, 5.500 J, and 9.800 J as exciters and impact horizontally.

[0011] Step Five: Use a velocimeter for the vibration pick-up. When using an accelerometer, numerical integration should be performed. The sampling interval is taken as 200 μS to 500 μS, and the cut-off frequency is taken as 120 Hz.

[0012] Step Six: Take the maximum value of the velocity curve as the vibration amplitude, perform Fourier spectrum analysis on the velocity curve, and the frequency corresponding to the extreme value is the resonance frequency.

[0013] Step Seven: Perform wavelet transform on the velocity curve, select the wavelet basis bior5.5, and the number of decomposition levels of wavelet is 6.

[0014] Step Eight: Determine the normal service performance of the structure by comparing the vibration amplitudes, resonance frequencies, and waveforms in each two-frequency band shown by wavelet packet decomposition between structural members under the same boundary conditions, different times of the same member, or before and after damage caused by external factors.

[0015] In a preferred solution, it also includes obtaining building structure data; the building structure data includes several component images, and each component image includes a component; feature extraction is performed on the component images to obtain the feature information of the components; according to the feature information, the information set of each component is determined through an expert system, and the information set includes the features of the component and the corresponding component type of the component, and the health score of the building structure is determined through the expert system.

[0016] In a preferred solution, the building structure also includes appearance quality inspection. The appearance quality of the load-bearing components of the building is inspected to understand component defects. During the appearance quality inspection process, key inspections need to be carried out according to the disaster areas understood during the engineering investigation, and their surface quality, structural stress, and node connection damage are inspected and icon-drawn; the influence on the interior of building components during the disaster occurrence process is inferred. For the component cross-section inspection of the building structure: the cross-section dimensions of the components are sampled and measured, a steel bar position detector is used to sample and detect the steel bar configuration of reinforced concrete columns, beams, and slabs, and some positions are chiseled and verified. During the inspection of beams and columns, the core sampling method is used to take core samples of building structure components and perform compressive strength tests in the natural drying state; according to the detection results of the building structure degree in each interval range and their average values, they are compared with the design strength grade, and the bearing capacity of the building structure is checked in combination with the detection results to determine whether it meets the original design requirements.

[0017] As can be seen from the above, a building structure test and detection method includes a rebound hammer, a vibration pick-up, and a dynamic tester, and specifically includes the following steps:

[0018] Step 1: The test points are located in the middle of the structure. For the convenience of testing, for beam members, the excitation points and the pick-up sensors are both located at the middle position of the bottom of the beam. For column members, the excitation points and the pick-up sensors are both located at the middle position longitudinally or transversely.

[0019] Step 2: Place a tool steel pad with a hardness of HRC60±2 on the impact surface at the excitation point.

[0020] Step 3: For beam members, use a rebound hammer with a nominal energy of 2.207 J as the exciter and impact upward.

[0021] Step 4: For column members, according to the size of the member, use rebound hammers with nominal energies of 2.207 J, 4.500 J, 5.500 J, and 9.800 J as exciters and impact horizontally.

[0022] Step 5: Use a velocimeter as the pick-up sensor. When using an accelerometer, numerical integration should be performed. The sampling interval is taken as 200 μS to 500 μS, and the cut-off frequency is taken as 120 Hz.

[0023] Step 6: Take the maximum value of the velocity curve as the vibration amplitude, perform Fourier spectrum analysis on the velocity curve, and the frequency corresponding to the extreme value is the resonance frequency.

[0024] Step 7: Perform wavelet transform on the velocity curve, select the wavelet basis bior5.5, and the number of decomposition levels of wavelet decomposition is 6 layers.

[0025] Step 8: Determine the normal service performance of the structure by comparing the vibration amplitudes, resonance frequencies, and waveforms in each two-frequency band shown by wavelet packet decomposition between structural members with the same boundary conditions, at different times of the same member, or before and after damage caused by external factors. The building structure test and detection method provided by the present invention has the following advantages:

[0026] Adopt the test of the dynamic stiffness of the test member to realize the detection and evaluation of the material properties and boundary support conditions. The excitation method is transient excitation. The dynamic stiffness parameters, that is, the vibration velocity and resonance frequency, are obtained through the calculation and analysis of the vibration curve. At the same time, the curves of each frequency band of the obtained vibration curve can be used as the information source for analyzing the structural member for different purposes.

[0027] The on-site operation of the present invention is simple, and it can quickly detect all the main beam and column components of the building structure. When excited with the same nominal energy, the dynamic stiffness of the structural component is negatively correlated with the vibration amplitude and positively correlated with the square of the resonance frequency. Under the same geometric shape and the same boundary support, the greater the dynamic stiffness, the worse the structural performance. When the quality of the beams on both sides of the column is qualified, but the dynamic stiffness is less than the normal value, it can be determined that there is a defect in the connection between the column and the beam, which cannot be quickly detected by the existing detection methods. For the damage caused by fire or other external factors during the normal service life of the building structure, the damage situation can be evaluated by comparing the decrease in the dynamic stiffness of the structural components before and after the damage or with the same boundary conditions of the undamaged structure components, and the effect after the structural reinforcement can be evaluated by the dynamic stiffness. After the completion of the construction project, the present invention is used to quickly detect all the main beam and column components of the structure and archive them as the original data curve. When it reaches the normal service life, the present invention is used to quickly detect all the main beam and column components of the structure again. After comparison, it provides a basis for determining whether it can continue to be used. After a large number of detections with the present invention, a database is formed. After statistics, it provides a criterion for judging whether the quality of the structural components is qualified. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 FIG. is an overall schematic diagram of a building structure test and detection method proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0030] Refer to Figure 1 , a building structure test and detection method, including a rebound hammer, a vibration pickup, and a dynamic tester, specifically including the following steps:

[0031] Step 1: The test points are located in the middle of the structure. For the convenience of testing, for beam components, the excitation point and the vibration pickup are both located at the middle position at the bottom of the beam. For column components, the excitation point and the vibration pickup are both located at the middle position longitudinally or transversely;

[0032] Step 2: Place a tool steel pad with a hardness of HRC60±2 on the impact surface at the excitation point;

[0033] Step 3: For beam components, a rebound hammer with a nominal energy of 2.207 J is used as the exciter and impacts upward;

[0034] Step 4: For column components, according to the size of the component, a rebound hammer with a nominal energy of 2.207 J, 4.500 J, 5.500 J, and 9.800 J is used as the exciter and impacts horizontally;

[0035] Step 5: Use a speedometer as the vibration pickup, and use an accelerometer to perform numerical integration. The sampling interval is 200μS to 500μS, and the cutoff frequency is 120Hz.

[0036] Step 6: Take the maximum value of the velocity curve as the vibration amplitude, perform Fourier spectrum analysis on the velocity curve, and the frequency corresponding to the extreme value is the resonance frequency;

[0037] Step 7: Perform wavelet transform on the velocity curve, select the wavelet basis bior5.5, and the wavelet decomposition level 6;

[0038] Step 8: Determine the normal performance of the structure by comparing the vibration amplitude, resonance frequency, and waveforms in each binary frequency band displayed by wavelet packet decomposition between structural components with the same boundary conditions, and the same component before and after damage caused by different times or external causes.

[0039] In a preferred embodiment, it also includes acquiring building structure data; the building structure data includes a plurality of component images, each of which includes a component; performing feature extraction on the component images to obtain feature information of the components; and determining, based on the feature information, an information set of each of the components through an expert system, the information set including the features of the components and the component type corresponding to the components.

[0040] In a preferred embodiment, the health score of the building structure is determined by the expert system.

[0041] In a preferred embodiment, the building structure also includes an appearance quality inspection, which is performed on the appearance quality of the building's load-bearing components to understand component defects. During the appearance quality inspection, it is necessary to conduct key inspections based on the disaster sites learned during the engineering investigation, check their surface quality, structural stress, and node connection damage, and draw icons; infer the impact of the disaster on the interior of the building components.

[0042] In a preferred embodiment, the cross-section inspection of the building structure components includes: sampling measurement of the cross-section dimensions of the components, sampling inspection of the steel bar configuration of reinforced concrete columns, beams and slabs using a steel bar position detector, and verification by chiseling some locations.

[0043] In a preferred embodiment, during the inspection of beams and columns, core sampling is performed on the building structure components using the core drilling method, and a compressive strength test is performed in a naturally dry state; the building structure test results in each interval range and their average values are compared with the design strength grade, and the bearing capacity of the building structure is verified in combination with the test structure to determine whether it meets the original design requirements.

[0044] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A building structure test and detection method, including a rebound hammer, a vibration pickup, and a dynamic tester, characterized in that, Specifically, it includes the following steps: Step 1: The test points are located in the middle of the structure. For the convenience of testing, for beam members, the excitation points and the pick-up sensors are both located at the middle position of the bottom of the beam. For column members, the excitation points and the pick-up sensors are both located at the longitudinal or transverse middle position; Step 2: Place a tool steel pad with a hardness of HRC60±2 on the impact surface at the excitation point; Step 3: For beam members, use a rebound hammer with a nominal energy of 2.207 J as the exciter and impact upward; Step 4: For column members, according to the size of the members, use rebound hammers with nominal energies of 2.207 J, 4.500 J, 5.500 J, and 9.800 J as the exciters and impact horizontally; Step 5: Use a velocimeter as the pick-up sensor. When using an accelerometer, numerical integration should be performed. The sampling interval is taken as 200 μS to 500 μS, and the cut-off frequency is taken as 120 Hz; Step 6: Take the maximum value of the velocity curve as the vibration amplitude, perform Fourier spectrum analysis on the velocity curve, and the frequency corresponding to the extreme value is the resonance frequency; Step 7: Perform wavelet transform on the velocity curve, select the wavelet basis bior5.5, and the number of layers of wavelet decomposition is 6 layers; Step 8: Determine the normal service performance of the structure by comparing the vibration amplitudes, resonance frequencies, and waveforms in each two-frequency band shown by wavelet packet decomposition between structural members with the same boundary conditions, before and after damage caused by different times or external factors to the same member.

2. A building structure test and detection method according to claim 1, characterized in that, It also includes obtaining building structure data; the building structure data includes a number of component images, each of the component images includes a component; extracting features from the component images to obtain the feature information of the components; according to the feature information, determining the information set of each of the components through an expert system, and the information set includes the features of the components and the corresponding component types of the components.

3. The method for testing and detecting a building structure according to claim 2, wherein, Determine the health score of the building structure through the expert system.

4. A building structure test and detection method according to claim 1, characterized in that, The building structure also includes appearance quality inspection. Conduct appearance quality inspection on the load-bearing components of the building to understand component defects. During the appearance quality inspection process, key inspections need to be carried out according to the disaster locations understood during the engineering investigation, and check their surface quality, structural stress, and joint connection damage and draw diagrams; infer the impact on the interior of building components during the disaster occurrence process.

5. A building structure test and detection method according to claim 1, characterized in that, Inspection of the component cross-sections of the building structure: Sample and measure the cross-sectional dimensions of the components, use a steel bar position detector to sample and detect the steel bar configuration of reinforced concrete columns, beams, and slabs, and conduct chiseling verification on some positions.

6. A building structure test and detection method according to claim 5, characterized in that During the inspection of the beams and columns, use the core drilling method to take cores from the building structure components and conduct compressive strength tests in the natural drying state; compare the detection results of the building structure degree in each interval range and their average values with the design strength grade, and combine the detection results to check the bearing capacity of the building structure to determine whether it meets the original design requirements.

Images