阅读说明：本技术 一种振弦式钢筋应力计检测混凝土支撑梁轴力的方法 (Method for detecting concrete supporting beam axial force by vibrating wire type steel bar stressometer ) 是由 马盛元 杨显达 赵仁基 陈海滨 刘建智 潘跃春 陈凡 兰贤东 陈航枫 陈必微 许 于 2021-01-22 设计创作，主要内容包括：本申请涉及一种振弦式钢筋应力计检测混凝土支撑梁轴力的方法,其包括如下步骤：S1:钢筋应力计埋设浇筑后,对钢筋应力计读数进行测量记录,以获取到初始频率值f-0；S2:将得到的初始频率值f-0减去钢筋应力计的出厂标定初始读数fs,以得出混凝土收缩影响修正值f-1；S3:基坑开挖；S4:测量出支撑梁内的钢筋应力计实测频率值f-c,并将混凝土收缩影响修正值f-1与实测频率值f-c相加,以得到修正频率值f；利用修正频率值f计算出混凝土轴力值F-T。本申请具有能提高对轴力F测量值准确性的效果。(The application relates to a method for detecting the axial force of a concrete supporting beam by a vibrating wire type steel bar stress meter, which comprises the following steps: s1, after the steel bar stress meter is buried and poured, the reading of the steel bar stress meter is measured and recorded to obtain an initial frequency value f 0 (ii) a S2, obtaining the initial frequency value f 0 Subtracting the factory calibration initial reading fs of the steel bar stressometer to obtain the concrete shrinkage influence correction value f 1 (ii) a S3, excavating a foundation pit; s4, measuring the actually measured frequency f of the steel bar stress meter in the support beam c And the concrete shrinkage influence correction value f is set 1 With the measured frequency value f c Adding to obtain a corrected frequency value f; calculating the concrete axial force value F by using the corrected frequency value F T . The method and the device have the effect of improving the accuracy of the measured value of the axial force F.)

1. A method for detecting the axial force of a concrete supporting beam by a vibrating wire type steel bar stress meter is characterized in that: the method comprises the following steps:

s1, after the steel bar stress meter is buried and poured, the reading of the steel bar stress meter is measured and recorded to obtain an initial frequency value f₀；

S2, obtaining the initial frequency value f₀Subtracting the factory calibration initial reading fs of the steel bar stressometer to obtain the concrete shrinkage influence correction value f₁；

S3, excavating a foundation pit;

s4, measuring the actually measured frequency f of the steel bar stress meter in the support beam_cAnd the concrete shrinkage influence correction value f is set₁With the measured frequency value f_cAdding to obtain a corrected frequency value f; calculating the concrete axial force value F by using the corrected frequency value F_T。

2. The method for detecting the axial force of the concrete supporting beam by the vibrating wire type steel bar stress gauge according to claim 1, wherein the method comprises the following steps:

and in the S1, measuring the numerical value of the steel bar stressometer for multiple times before the steel bar stressometer is embedded and poured into the foundation pit and excavated, and selecting the frequency value with stable later reading as the initial frequency value f₀。

3. The method for detecting the axial force of the concrete supporting beam by the vibrating wire type steel bar stress gauge according to claim 2, wherein the method comprises the following steps:

s5, when the supporting beam is poured, the same batch of concrete is utilized, a simulation section is manufactured according to the actual reinforcement of the supporting beam, and a reinforcing steel bar stress meter for simulation is embedded according to requirements; this step is performed in synchronization with S1;

s6, when the section to be simulated reaches the standard concrete age, heating the section for a long time by using a solar lamp under the condition of constant load, and applying constant load to the section by using a static load instrument; continuously measuring the surface temperature of the steel bar stress meter for simulation in the process of naturally cooling the simulation section to obtain a corresponding simulation section temperature value; establishing a coordinate system by taking the increasing direction of the simulation section temperature value as an X axis and the increasing direction of the frequency value measured by a steel bar stress meter under the corresponding temperature as a Y axis; according to the obtained scatter diagram and the regression linear equation, the linear slope is used as the temperature correction coefficient K_T。

4. The method for detecting the axial force of the concrete supporting beam by the vibrating wire type steel bar stress gauge according to claim 3, wherein the method comprises the following steps:

in the step S4, the measured frequency value f of the steel bar stress meter is measured_cSimultaneously, the actually measured surface temperature value of the steel bar stress meter in the supporting beam is measuredT; and records the initial temperature value T of the support beam₀(ii) a Subtracting the initial temperature value T from the measured surface temperature value T₀To obtain the temperature difference, and then the temperature difference and the temperature correction coefficient K_TMultiplying, and adding the obtained numerical value with the corrected frequency value f obtained in the step S4 to obtain a new frequency corrected value f; finally, calculating a new concrete axial force value F_T。

5. The method for detecting the axial force of the concrete supporting beam by the vibrating wire type steel bar stress gauge according to claim 4, wherein the method comprises the following steps:

and in the step S5, the steel bar stress meter is installed strictly according to the requirement, and whether the steel bar stress meter is normal is checked again before the concrete is poured.

6. The method for detecting the axial force of the concrete supporting beam by the vibrating wire type steel bar stress gauge according to claim 5, wherein the method comprises the following steps:

and when the section to be simulated in the S6 reaches the age of the standard concrete, performing a compression test on the simulated section.

7. The method for detecting the axial force of the concrete supporting beam by the vibrating wire type steel bar stress gauge according to claim 6, wherein the method comprises the following steps:

and in the step S6, after the temperature heating test of the simulated section is finished, performing a compression test on the simulated section.

8. The method for detecting the axial force of the concrete supporting beam by the vibrating wire type steel bar stress gauge according to claim 4, wherein the method comprises the following steps:

s7, obtaining the final concrete axial force value F_TAnd (4) bringing a comparison table of the standard load and the actual load of the simulated section, and obtaining the axial force F after modulus correction by using a linear interpolation method.

Technical Field

The application relates to the field of concrete support beam axial force detection, in particular to a method for detecting concrete support beam axial force by a vibrating wire type steel bar stress meter.

Background

The foundation pit refers to a soil pit excavated at the designed position of the foundation according to the elevation of the foundation and the plane size of the foundation. Before excavation, an excavation scheme is determined according to geological and hydrological data and the conditions of buildings nearby the site, and waterproof drainage work is performed. The axial force monitoring of the first-level foundation pit concrete supporting beam is a necessary measurement project according to the requirements of the technical Specification for monitoring the construction foundation pit engineering.

At present, the axial force of a first-level foundation pit concrete support beam is usually detected by adopting a vibrating wire type steel bar stressometer; the vibrating wire type steel bar stress meter is usually used in cooperation with a multifunctional computer detector, and when the steel bar in a tested structure bears stress, the steel bar stress meter converts the stress into a frequency signal and directly calculates the stress for digital display.

In order to the above-mentioned correlation technique, the inventor thinks that there is when utilizing vibration wire formula reinforcing bar stressometer to detect the concrete supporting beam axial force section, the ubiquitous actual measurement axial force does not accord with operating condition with actual working, and the actual measurement axial force is with the great problem of operating condition measured value fluctuation. The reason for this is mainly because the measurement does not take the drying shrinkage of the concrete at the solidification stage into consideration, thereby causing a large error to the measurement result.

Disclosure of Invention

In order to improve the problem that there is great error in the detection of vibrating wire formula reinforcing bar stress meter to concrete supporting beam axle power, this application provides a vibrating wire formula reinforcing bar stress meter detects concrete supporting beam axle power's method.

The application provides a method for detecting concrete supporting beam axial force by a vibrating wire type steel bar stress meter, which adopts the following technical scheme:

a method for detecting the axial force of a concrete supporting beam by a vibrating wire type steel bar stress meter comprises the following steps:

s1, after the steel bar stress meter is buried and poured, the reading of the steel bar stress meter is measured and recorded to obtain an initial frequency value f₀；

S2, obtaining the initial frequency value f₀Subtracting the factory calibration initial reading fs of the steel bar stressometer to obtain the concrete shrinkage influence correction value f₁；

S3, excavating a foundation pit;

s4, measuring the actually measured frequency f of the steel bar stress meter in the support beam_cAnd the concrete shrinkage influence correction value f is set₁With the measured frequency value f_cAdding to obtain a corrected frequency value f; calculating the concrete axial force value F by using the corrected frequency value F_T。

By adopting the technical scheme, in order to reduce the influence of the shrinkage during the concrete solidification on the initial measurement reading of the steel bar stress meter, the initial frequency value f is measured and calculated₀Subtracting the factory calibration initial reading fs of the steel bar stressometer so as to obtain the concrete shrinkage influence correction value f₁(ii) a Finally, the final actual measurement frequency value f of the steel bar stress meter_cCorrection value f for influence of concrete shrinkage₁Adding the data so as to reduce the influence of shrinkage on the initial reading in the concrete setting process; the accuracy of later data measurement is improved.

Preferably, the numerical value of the steel bar stress meter in the S1 is measured for multiple times before the steel bar stress meter is embedded and poured into the foundation pit for excavation, and the frequency value after the reading is stable at the later stage is selected as the initial frequency value f₀。

By adopting the technical scheme, the numerical value of the steel bar stress meter is measured for multiple times, and the initial frequency value f with the most accurate reading is selected₀Thereby enabling to reduce the measurementThe error of (2) improves the accuracy of the data and reduces the deviation of the data.

Preferably, S5, when the supporting beam is poured, the same batch of concrete is utilized, the simulated section is manufactured according to the actual reinforcing bars of the supporting beam, and the reinforcing bar stressometers for simulation are embedded according to requirements; this step is performed in synchronization with S1;

s6, when the section to be simulated reaches the standard concrete age, heating the section for a long time by using a solar lamp under the condition of constant load, and applying constant load to the section by using a static load instrument; continuously measuring the surface temperature of the steel bar stress meter for simulation in the process of naturally cooling the simulation section to obtain a corresponding simulation section temperature value; establishing a coordinate system by taking the increasing direction of the simulation section temperature value as an X axis and the increasing direction of the frequency value measured by a steel bar stress meter under the corresponding temperature as a Y axis; according to the obtained scatter diagram and the regression linear equation, the linear slope is used as the temperature correction coefficient K_T。

By adopting the technical scheme, the change of the internal temperature of the supporting beam also influences the measured value of the steel bar stress meter, and when the axial force of the supporting beam is measured, the temperature in the concrete is actually measured, and then the temperature correction coefficient K is obtained according to the obtained temperature correction coefficient_TThe temperature stress is corrected, and the influence of the temperature on the measured value of the steel bar stress meter can be further reduced by correcting the temperature stress interference caused by non-load; the accuracy of the measured value is further improved.

Preferably, in S4, the measured frequency value f of the steel bar stress meter is measured_cSimultaneously, measuring a surface temperature value T actually measured by a steel bar stress meter in the supporting beam; and records the initial temperature value T of the support beam₀(ii) a Subtracting the initial temperature value T from the measured surface temperature value T₀To obtain the temperature difference, and then the temperature difference and the temperature correction coefficient K_TMultiplying, and adding the obtained numerical value with the corrected frequency value f obtained in the step S4 to obtain a new frequency corrected value f; finally, calculating a new concrete axial force value F_T。

By adopting the technical scheme, the pairAxial force value F of concrete_TWhen the calculation is carried out, the dry shrinkage and the temperature change during the concrete solidification period can be used for the concrete axial force value F through the calculation formula_TThe caused influence is synchronously corrected; increase the concrete axial force value F from two dimensions_TThe accuracy of (2).

Preferably, in S5, the steel bar stress meter is installed strictly according to the requirement, and before the concrete is poured, whether the steel bar stress meter is normal is checked again.

By adopting the technical scheme, the steel bar stress meter is checked for many times, so that errors caused by the quality problem of the steel bar stress meter to the detection numerical value can be prevented; the accuracy of the final measurement result is ensured.

Preferably, in S6, when the section to be simulated reaches the standard concrete age, the simulated section is subjected to a compression test.

Through adopting above-mentioned technical scheme, thereby carry out compressive test to the simulation section and can detect out whether qualified to the intensity of concrete supporting beam, can also detect out the compressive strength of concrete simultaneously.

Preferably, in S6, after the temperature heating test of the simulated cross section is completed, the simulated cross section is subjected to a compression test.

By adopting the technical scheme, after the concrete supporting beam is heated, the strength of the concrete supporting beam can be influenced to a certain extent; the concrete support beam after being heated is subjected to a compression test, so that the strength values of the concrete support beam at different temperatures can be obtained.

Preferably, S7, the final concrete axial force value F_TAnd (4) bringing a comparison table of the standard load and the actual load of the simulated section, and obtaining the axial force F after modulus correction by using a linear interpolation method.

By adopting the technical scheme, the actual measured axial force of the concrete calculated according to the elastic modulus parameters and the standard load of the simulated section are compared and corrected, so that the axial force calculation error caused by the calculation of the concrete modulus parameter deviation can be reduced; especially the error amount generated by the deviation of the parameter under the high load force state.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the initial reading deviation caused by shrinkage during concrete solidification is reduced;

2. reducing the error of the non-load stress generated by temperature change to the actually measured axial force;

3. reducing the axial force calculation error caused by calculating the concrete modulus parameter deviation; especially the error amount generated by the deviation of the parameter under the high load force state.

Drawings

FIG. 1 is a flow chart of a method for detecting an axial force of a concrete support beam by a vibrating wire type steel bar stress meter.

Fig. 2 is a table of the temperature correction coefficient K values in the wenzhou foreign language school.

FIG. 3 is a table of correction coefficients K for the temperature of the cold-chain logistics center in Wenzhou.

FIG. 4 is a table of values of the coefficients of correction of the Xanthium sibiricum and the homestead temperature K.

Detailed Description

The present application is described in further detail below with reference to figures 1-4.

The embodiment of the application discloses a method for detecting an axial force of a concrete supporting beam by using a vibrating wire type steel bar stress meter. Since the concrete is solidified, the shrinkage stress is generated, and the part of the stress is generated by the unrealistic load, so that the shrinkage stress is eliminated. At present, in the actual measurement process, the reading of the initial steel bar stress meter is selected randomly, so that the shrinkage load is superimposed to the calculation of the subsequent testing axial force, and the calculation value of the subsequent axial force is greatly interfered and influenced. Furthermore, temperature changes can also affect the measurement of the axial force of the support beam.

In the related technology, the value of the concrete modulus is taken according to the concrete elastic modulus of concrete structure design specifications, the stress increase mode of the actual foundation pit supporting beam is monotonously increased along with the increase of the excavation depth of the foundation pit, meanwhile, the foundation pit supporting beam belongs to a temporary structure, the safety storage of the structural design is relatively low, the plastic strain of the concrete develops along with the increase of the stress in the later stage of excavation of the foundation pit, and the concrete elastic modulus can not accurately reflect the stress change process. Therefore, when the concrete support beam is in a stage with larger stress, the modulus parameter adopts the elastic modulus in the process of calculating the concrete axial force based on the theory of cooperative deformation of the steel bars and the concrete, and the accuracy of the calculation result can be reduced.

In order to improve the influence of the three factors on the actual axial force measurement value of the support beam, the application discloses a method for detecting the axial force of a concrete support beam by using a vibrating wire type steel bar stress meter, which comprises the following steps:

s1, embedding the steel bar stressometers and pouring concrete, measuring the numerical value of the steel bar stressometers for multiple times before embedding and pouring the steel bar stressometers into the foundation pit, and selecting the frequency value with stable reading at the later stage as the initial frequency value f₀。

S2, obtaining the initial frequency value f₀Subtracting the factory calibration initial reading fs of the steel bar stressometer to obtain the concrete shrinkage influence correction value f₁。

S3, excavating a foundation pit;

s4, when the foundation pit is excavated, the measured frequency value f of the steel bar stress meter in the supporting beam is measured for multiple times_cAnd an average is taken. Then the concrete shrinkage influence correction value f is set₁With the measured frequency value f_cAnd adding to obtain a preliminary corrected frequency value f.

And S5, manufacturing a simulated section in the early construction stage, pouring a support beam, simultaneously manufacturing the simulated section by using the same batch of concrete according to the actual reinforcement of the support beam, and embedding a reinforcing steel bar stress meter for simulation according to requirements. And (4) installing the steel bar stress meter according to strict requirements, and checking whether the steel bar stress meter is normal again before pouring concrete. This step is performed in synchronization with S1.

S6 measured frequency value f of the stress meter of the steel bar in S4_cAnd measuring the actually measured surface temperature value T of the steel bar stress meter in the supporting beam while measuring. And records the initial temperature value T of the support beam₀. When the simulated section reaches the standard concrete age, the simulated section is heated for a long time by using a high-wattage solar lamp under the condition of constant load, and then the section is recycledAnd the RS-JYB full-automatic static load instrument applies constant load to the simulation section. And when the simulated section is naturally cooled, continuously measuring the surface temperature of the steel bar stress gauge for simulation and obtaining a corresponding simulated section temperature value. And establishing a coordinate system by taking the increasing direction of the simulation section temperature value as an X axis and the increasing direction of the frequency value measured by the corresponding simulation steel bar stress meter at the temperature as a Y axis.

According to the obtained scatter diagram and the regression linear equation, the linear slope is used as the temperature correction coefficient K_T. Subtracting the initial temperature value T from the actually measured surface temperature value T of the steel bar stressometer in the supporting beam₀To obtain the temperature difference, and then the temperature difference and the temperature correction coefficient K_TMultiplying, and then multiplying the obtained value with the actually measured frequency value f_cConcrete shrinkage influence correction value f₁Adding to obtain final frequency correction value f, wherein f = f_c+f₁+K_T（T-T₀). Finally, calculating the final concrete axial force value F_T. And after the temperature heating test of the simulated section is finished, performing a compression test on the simulated section. In this embodiment, the simulation cross section may be subjected to a compression test by an ultrasonic rebound synthesis method or an impact echo method.

S7, obtaining the final concrete axial force value F_TAnd (4) bringing a comparison table of the standard load and the actual load of the simulated section, and obtaining the axial force F after modulus correction by using a linear interpolation method.

Because the manufacture of the simulation section and the construction of the supporting beam are carried out simultaneously, the manufacture of a construction unit is convenient, and the manufacture cost is lower. The measuring and calculating interference on the concrete supporting beam is reduced from three dimensions, and the accuracy performance of the finally measured and calculated concrete supporting beam axial force value is greatly improved. And favorable safety guarantee is provided for the foundation pit informatization construction through high-accuracy detection data.

By carrying out field measurement on three construction sites of a Wenzhou foreign language school construction site, a Wenzhou modern cold chain logistics center, a Canari and a home, 3 groups of simulation sections are manufactured on each construction site by using the same batch of concrete while supporting beam construction is carried out on each construction site. The height is 50cm, the section size and the reinforcing bars of the section are according to the design requirements, and 4 steel bar stressometers are symmetrically embedded in the concrete section. And 3 groups of simulation sections which are manufactured on site and embedded with the steel bar stressometers are subjected to temperature tests to obtain the temperature average correction coefficient K value of the concrete axial force monitoring section of each construction site, which is detailed in figures 2-4. The concrete surface temperature is measured in the monitoring process of each construction site, and the temperature of the measured value is corrected. Finally, the fluctuation of the measured value caused by the temperature change is greatly reduced. When the indoor data analysis is used for calculating the concrete axial force, the axial force values after shrinkage correction and temperature correction are brought into a comparison table of the standard load and the actual load of the simulated section, and the axial force after modulus correction is obtained by using a linear interpolation method.

The beneficial effects of the method for detecting the axial force of the concrete supporting beam by the vibrating wire type steel bar stressometer in the embodiment of the application are as follows: the initial reading deviation caused by shrinkage during concrete setting is reduced. And the error of the non-load stress generated by temperature change to the actually measured axial force is reduced. Reducing the axial force calculation error caused by calculating the concrete modulus parameter deviation; especially the error amount generated by the deviation of the parameter under the high load force state. The accurate value of the axial force F measurement is improved.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.