CN103335858A - Method for measuring bridge structure dynamic displacement and vibration frequency - Google Patents

Abstract

A method for measuring dynamic displacement and vibration frequency of a bridge structure, the steps of which are: (1) establishing a bridge structure vibration field monitoring system, synchronously collecting vibration displacement and GNSS time; (2) coordinate system projection conversion; first calculating the local coordinate system and The projection parameters between the independent coordinate systems of the bridge, and then transform the measured structure vibration coordinate projection to the independent coordinate system of the bridge; (3) filter the gross error of the vibration displacement of the bridge structure; (4) re-sample the vibration displacement by the linear interpolation method; (5 ) using Chebyshev filter to separate the quasi-static part and dynamic part in the displacement; (6) using fast Fourier method to analyze the frequency spectrum of the vibration signal. The invention has the advantages of non-contact, high precision, high reliability, high automation and the like.

Description

A Measuring Method of Dynamic Displacement and Vibration Frequency of Bridge Structure

technical field

The invention mainly relates to the technical field of bridge structure health monitoring, in particular to a method for measuring dynamic displacement and vibration frequency of bridge structures.

Background technique

Monitoring and diagnosing the dynamic performance of bridge structures, as well as timely damage assessment and safety warning are of great significance to improving bridge operation efficiency and avoiding heavy casualties and property losses. Among them, quasi-static displacement, dynamic displacement and vibration frequency are important parameters to reflect the dynamic performance of bridge structures. Moreover, monitoring the long-period quasi-static displacement and short-period dynamic displacement in bridge structural vibration is the difficulty of bridge structural health monitoring at present.

Conventional instruments for measuring dynamic parameters of bridge structures are mainly accelerometers, but they have the following defects:

(1) The accelerometer can only measure the vibration signal of the bridge structure through a contact method. For difficult-to-reach parts such as bridge towers, the operation is very inconvenient and the measurement is difficult.

(2) The accelerometer is used to directly measure the acceleration of structural vibration. After integration, only the relative displacement of the structural vibration can be obtained, and the absolute displacement cannot be obtained, which makes it difficult for the accelerometer to perform continuous monitoring for a long time.

(3) During the monitoring process, a high-pass filter needs to be used to eliminate the trend item generated in the two integration processes. The accelerometer can only measure the short-period dynamic displacement in the structural vibration, and cannot measure the long-period quasi-static displacement.

In the prior art, there is another automatic total station, which has the advantages of automatic target recognition, automatic target tracking, automatic measurement, automatic recording, and high measurement accuracy, and its measurement accuracy reaches millimeter level, even submillimeter Level accuracy, so it is often used for high-precision deformation monitoring of engineering structures such as slopes, dams, bridges, and tunnels, but it cannot be used for dynamic deformation and vibration frequency measurement of bridge structures. The main reasons are:

(1) Due to low time resolution, omission of measurement data, noise interference and other reasons, with the current measurement method, the automatic total station can only measure the quasi-static displacement of the engineering structure, and cannot measure the short-period dynamic displacement and vibration frequency.

(2) Since the automatic total station uses the electrical signal generated by the quartz crystal oscillating circuit to time the time, its time accuracy is difficult to meet the requirements of structural vibration measurement.

Contents of the invention

The technical problem to be solved by the present invention is: aiming at the technical problems existing in the prior art, the present invention provides a non-contact, high-precision, high-reliability, and high-automation method for measuring the dynamic displacement and vibration frequency of bridge structures.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

A method for measuring dynamic displacement and vibration frequency of a bridge structure, the steps of which are:

(1) Establish a bridge structure vibration on-site monitoring system to collect vibration displacement and GNSS time synchronously; use the tracking mode of the automatic total station to collect bridge structure vibration displacement information, use the GNSS signal receiver to synchronously collect high-precision GNSS time and update the automatic total station station time;

(2) Coordinate system projection conversion; first calculate the projection parameters between the local coordinate system and the bridge independent coordinate system, and then transform the measured structural vibration coordinate projection into the bridge independent coordinate system;

(3) Filter the gross error of vibration displacement of the bridge structure; according to the prior information of the bridge structure vibration, set the displacement boundary value and eliminate the gross error; according to the time information in each row of data records, filter the same time information caused by data record errors row of data;

(4) The linear interpolation method resamples the vibration displacement; according to the nominal sampling rate of the automatic total station, the measured information is resampled by the linear interpolation method, and the missing value is repaired;

(5) Using the Chebyshev filter to separate the quasi-static part and the dynamic part in the displacement;

(6) Use the fast Fourier method to analyze the frequency spectrum of the vibration signal; perform frequency spectrum analysis on the measured x(n), y(n), and z(n) displacement sequences to obtain the vertical, horizontal, and vertical vibration frequencies of the bridge structure .

As a further improvement of the present invention:

The step (2) is to convert the coordinates and time (E, N, H, T) of the monitoring point in the local coordinate system to the coordinates and time (x, y, z, t) in the independent coordinate system of the bridge, using The following formula (1) performs coordinate projection transformation:

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the formula, i=1, 2, 3..., N, N is the total amount of records, and α represents the azimuth of the longitudinal axis direction of the monitored bridge 8 in the local coordinate system:

α=arctan[(E ₂ -E ₁ )/(N ₂ -N ₁ )] (2)

In the formula, α represents the azimuth of the longitudinal axis of the monitored bridge in the local coordinate system, (E ₁ , N ₁ ), (E ₂ , N ₂ ) are the coordinates of two points on the longitudinal axis of the bridge deck in the local coordinate system; The local coordinate system is the Cartesian coordinate system commonly used in the location of the monitored bridge; the bridge independent coordinate system is a Cartesian coordinate system in which the longitudinal axis of the bridge is the x direction, the horizontal axis of the bridge is the y direction, and the vertical axis of the bridge is the z direction.

Before performing the step (1), the time resolution of the automatic total station is increased from 1s to 0.01s, and the automatic total station is calibrated on the standard baseline to obtain its ranging addition constant.

The concrete process of described step (1) is: a circular prism is set at the first datum point, as the backsight point; 360 ° prism is installed at the bridge deck of the monitored bridge on the river and/or the monitoring point of bridge tower, An automatic total station is placed at the second reference point, and a GNSS signal receiver is installed on the top of the automatic total station. According to the known three-dimensional coordinates of the first reference point and the second reference point, the first reference point is used A reference point circular prism is oriented, and a station is built at the monitoring site to form a four-dimensional vibration monitoring system including three-dimensional vibration displacement and GNSS time information.

The concrete process of described step (4) is: adopt the method for linear interpolation to mend missing value, omit the displacement value of t moment between _t1 moment and _t2 moment, calculate the displacement value (x, y, z) of t moment:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="t"\; filenames="HDA00003310701000012.png"\; state="\{\{state\}\}">t</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\\ \mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="1"\; label="y"\; filenames="HDA00003310701000012.png"\; state="\{\{state\}\}">y</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\\ \mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, (x ₁ , y ₁ , z ₁ ) is the displacement value at time t ₁ , and (x ₂ , y ₂ , z ₂ ) is the displacement value at time t ₂ , using an automatic total station with a nominal sampling rate of 10Hz , the data recording interval is 0.1s, so the above-mentioned time values t ₁ , t ₂ , and t are multiples of 0.1s.

The concrete process of described step (5) is: choose 0.01Hz to be the cut-off frequency that separates quasi-static displacement and dynamic displacement, and I type Chebyshev high-pass filter is:

${\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; w</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; jw</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In the above formula, ε is the ripple coefficient, n is the order, ω ₀ is the cut-off frequency, and T _n (w/w ₀ ) represents the n-order Chebyshev polynomial:

${\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; w</span>}<span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>\\ \mathrm{<span\; class="notranslate">\; cosh</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; w</span>}<span\; class="notranslate">\; )</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

The designed ripple coefficient ε is 0.1, the cut-off frequency ω ₀ is 0.01Hz, the order n is 8, and the I-type Chebyshev high-pass filter with passband ripple decomposes the quasi-static part and dynamic part in the vibration displacement.

Compared with the prior art, the present invention has the advantages of:

1. The present invention can simultaneously monitor the long-period quasi-static displacement, short-period dynamic displacement and vibration frequency of the dynamic response of the structure, thereby successfully solving the difficulty of simultaneously monitoring the dynamic displacement and the quasi-static displacement.

2. The measurement accuracy of the present invention is high, and can reach mm-level displacement measurement accuracy, and the accuracy is obviously higher than all conventional measurement methods in the prior art.

3. The present invention can measure the three-dimensional absolute displacement of structural vibration, and at the same time obtain the dynamic response of the bridge in the vertical, horizontal and vertical directions, obtain the absolute value of deformation, and finally realize the long-term monitoring of the deformation of the bridge structure.

4. The monitoring signal of the measurement method of the present invention includes the GNSS time with nanosecond precision, thereby creating conditions for the comparison and fusion of the monitoring signal and monitoring signals of other equipment. That is, the measurement method of the present invention realizes the structure through processes such as collecting high-precision GNSS time by an external GNSS signal receiver, coordinate system projection conversion, Chebyshev filter decomposition displacement, linear interpolation to repair missing values, and fast Fourier transform spectrum analysis. Dynamic displacement and vibration frequency measurement, simultaneously measure long-period quasi-static displacement, short-period dynamic displacement and vibration frequency of structural vibration.

5. By adopting the measurement method of the present invention, a new non-contact dynamic response monitoring method can be provided for bridge structure health monitoring, and then the non-contact, high-precision, high-reliability and high-automation measurement of bridge structure dynamic parameters can be realized , will become a new non-contact structural dynamic performance monitoring means, and has broad application prospects.

Description of drawings

Fig. 1 is a schematic flow chart of the measurement method of the present invention.

Fig. 2 is a schematic diagram of the arrangement of instruments in a specific application example of the present invention.

Fig. 3 is a schematic diagram of the vibration displacement of the bridge structure in a specific application example of the present invention.

Fig. 4 is a schematic diagram of the vibration quasi-static displacement of the bridge structure in a specific application example of the present invention.

Fig. 5 is a schematic diagram of the vibration dynamic displacement of the bridge structure in a specific application example of the present invention.

Fig. 6 is a schematic diagram of the vibration displacement spectrum of a bridge structure in a specific application example of the present invention.

illustration:

1. Round prism; 2. First reference point; 3. GNSS signal receiver; 4. Automatic total station; 5. Second reference point; 6. 360°prism; 7. Bridge deck monitoring point; 8. By Monitoring bridges; 9, rivers.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the measuring method of bridge structure dynamic displacement and vibration frequency of the present invention may further comprise the steps:

(1) The built-in program of the automatic total station 4 is upgraded and calibrated, and the automatic total station 4 is used to collect displacement data.

Optimize the built-in program of the automatic total station 4, increase its time resolution from 1s to 0.01s, and upgrade the core frame format of the built-in program.

The automatic total station 4 is calibrated on the standard baseline to obtain its ranging addition constant. Wherein, the calculation formula of additive constant is: k=D _AC -D _AB -D _BC , D _AC , D _AB , D _BC are respectively the horizontal distances of the line segments AC, AB, BC measured by the automatic total station 4, and A The three points , B and C are on the same straight line; that is, the line segments AB and BC are on the same straight line, and the two lines AB and BC form the line segment AC. The automatic total station 4 is used to measure the horizontal distances D _AC , D AB , and D BC of the line segments AC, _AB , and _BC respectively, and the additive constant of the automatic total station 4 is calculated as: k=D _AC -D _AB -D _BC .

(2) Establish an on-site monitoring system for bridge structure vibration, and collect vibration displacement and GNSS time synchronously.

Referring to Fig. 2, circular prism 1 is set at first datum point 2, as backsight point; 360 ° prism 6 is installed at the bridge deck of monitored bridge 8 on river 9 and/or bridge deck monitoring point 7 of pylon, The 360° prism 6 is connected to the base, and the base is fixed on the monitored bridge 8 through a U-shaped bracket, and the base screw is adjusted so that the vertical axis of the 360° prism 6 is vertical. An automatic total station 4 is placed at the second reference point 5, and a GNSS signal receiver 3 is installed on the top of the automatic total station 4, and the GNSS signal receiver 3 can pass through the automatic total station 4 Built-in interface for seamless connection, according to the known three-dimensional coordinate values of the first reference point 2 and the second reference point 5, use the first reference point circular prism 1 to orientate, and build a station at the monitoring site, consisting of three-dimensional vibration displacement and GNSS time information 4D vibration monitoring system. The GNSS signal receiver 3 collects GNSS time with nanosecond precision in real time, and updates the time of the automatic total station 4 in real time, and the automatic total station 4 synchronously collects three-dimensional displacement and time signals of bridge structure vibration.

After the above structure is adopted, the tracking mode of the automatic total station 4 is used to collect the vibration displacement information of the bridge structure, and the GNSS signal receiver 3 is used to synchronously collect high-precision GNSS time, so that the structural vibration displacement and GNSS time are seamlessly realized through the interface of the instrument Fusion, and real-time update of the automatic total station 4 time.

The automatic total station 4 synchronously collects GNSS time and vibration displacement of the bridge structure, and the data at each moment is recorded in the following format:

Number P _i , GNSS time T _i , east coordinate E _i , north coordinate N _i , elevation H _i ; where i=1, 2, 3..., N, N is the total amount of records.

(3) Coordinate system projection transformation.

The automatic total station 4 collects the structural vibration displacement signal based on the local coordinate system, first calculates the projection parameters between the local coordinate system and the bridge independent coordinate system, and then converts the measured structural vibration coordinate projection into the bridge independent coordinate system, Convert the coordinates and time (E, N, H, T) of bridge deck monitoring point 7 in the local coordinate system to the coordinates and time (x, y, z, t) in the independent coordinate system of the bridge, using the following formula (1 ) for coordinate projection transformation:

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the formula, i=1, 2, 3..., N, N is the total amount of records, and α represents the azimuth of the longitudinal axis direction of the monitored bridge 8 in the local coordinate system:

α=arctan[(E ₂ -E ₁ )/(N ₂ -N ₁ )] (2)

In the formula, α represents the azimuth of the monitored bridge 8 longitudinal axis in the local coordinate system, (E ₁ , N ₁ ), (E ₂ , N ₂ ) are the coordinates of two points on the longitudinal axis of the bridge deck in the local coordinate system . The local coordinate system is a Cartesian coordinate system commonly used in the location of the monitored bridge 8; the bridge independent coordinate system is a Cartesian coordinate system in which the longitudinal axis of the bridge is the x direction, the horizontal axis of the bridge is the y direction, and the vertical axis of the bridge is the z direction.

(4) Filter the gross error of bridge structure vibration displacement.

According to the prior information of bridge structure vibration, the displacement boundary value is set to eliminate gross errors; according to the time information in each row of data records, the data rows with the same time information caused by data recording errors are filtered.

The prior information of the bridge structure vibration is based on the actual size and material of the bridge structure, using the finite element method to calculate the displacement peak τ, taking 3τ as the displacement boundary value, and directly eliminating the displacement value greater than 3τ. The tracking mode adoption rate of the automatic total station 4 reaches 10Hz. The instrument records real-time data including point number P, time t, longitudinal coordinate x, transverse coordinate y, and vertical coordinate z. Due to the high frequency of data update and recording, there will be For the phenomenon of duplication and omission of data, according to the time t in the data record, the duplicate data records are directly eliminated.

(5) The linear interpolation method resamples the vibration displacement.

Due to the high frequency of data update and recording, there will be data omission phenomenon. Due to the uneven distribution of omission data, if this data is directly used for dynamic displacement and spectrum analysis, the precision and accuracy will be significantly reduced. It must be based on the automatic total station The nominal sampling rate is 4, and the measured information is resampled by linear interpolation to repair missing values.

Use the linear interpolation method to repair the missing value, the displacement value at time t is missing between time t ₁ and time t ₂ , and calculate the displacement value (x, y, z) at time t:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="t"\; filenames="HDA00003310701000012.png"\; state="\{\{state\}\}">t</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\\ \mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; <figure-callout\; id="1"\; label="y"\; filenames="HDA00003310701000012.png"\; state="\{\{state\}\}">y</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\\ \mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="z"\; filenames="HDA00003310701000012.png"\; state="\{\{state\}\}">z</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, (x ₁ , y ₁ , z ₁ ) is the displacement value at time t ₁ , and (x ₂ , y ₂ , z ₂ ) is the displacement value at time t ₂ , using an automatic total station with a nominal sampling rate of 10Hz , the data recording interval is 0.1s, so the above-mentioned time values t ₁ , t ₂ , and t are multiples of 0.1s. The displacement after resampling is shown in Figure 3. The horizontal axis in the figure represents time (time), and the vertical axis represents displacement (Displacement), including structural vibration longitudinal displacement (x-axis), lateral displacement (y-axis), vertical There are three parts of displacement (z-axis) data.

(6) Using Chebyshev filter to separate the quasi-static part and dynamic part in the displacement.

The change period of the long-period quasi-static displacement caused by the external load is several minutes or longer, and its change frequency is less than 0.01 Hz. The vibration frequency of engineering structures is usually 0.1 Hz to 10 Hz, so 0.01 Hz is selected as the separation quasi-static displacement. and the cutoff frequency of the dynamic displacement, the type I Chebyshev high-pass filter is:

${\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; w</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; jw</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In the above formula, ε is the ripple coefficient, n is the order, ω ₀ is the cut-off frequency, and T _n (w/w ₀ ) represents the n-order Chebyshev polynomial:

${\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; w</span>}<span\; class="notranslate">\; <</span>{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>\\ \mathrm{<span\; class="notranslate">\; cosh</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; arccos</span>}\frac{\mathrm{<span\; class="notranslate">\; w</span>}}{{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="0"\; label="w"\; filenames="HDA00003310701000022.png"\; state="\{\{state\}\}">w</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; w</span>}<span\; class="notranslate">\; )</span>\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

The designed ripple coefficient ε is 0.1, the cut-off frequency ω ₀ is 0.01Hz, the order n is 8, and the I-type Chebyshev high-pass filter with passband ripple decomposes the quasi-static part and dynamic part in the vibration displacement. Using the Chebyshev filter designed above to separate and decompose the structural vibration displacement is shown in Figure 3, the decomposed quasi-static displacement is shown in Figure 4, and the decomposed dynamic displacement is shown in Figure 5.

(7) The fast Fourier method analyzes the frequency spectrum of the vibration signal.

A specific window function is used to convert the corrected structural vibration signal from the time domain to the frequency domain, and to analyze the frequency spectrum of the structural vibration signal to obtain the structural vibration frequency. Spectrum analysis is performed on the measured x(n), y(n), z(n) displacement sequences respectively, and the longitudinal, lateral and vertical vibration frequencies of the bridge structure can be obtained, as shown in Figure 6, which is the vibration displacement spectrum of the bridge structure schematic diagram.

The analysis methods in each direction are the same, and the z(n) displacement sequence is taken as an example below. Perform discrete Fourier transformation on z(n) in the time domain to obtain the frequency domain function Z(k):

$Z\left(k\right)=\underset{\mathrm{no}=0}{\overset{N-1}{\mathrm{\&Sigma;}}}z\left(\mathrm{no}\right)e^{-j\frac{2\mathrm{\&pi;}}{N}\text{k n}}$ k=0, 1, 2..., N-1

In the formula, the length of z(n) is M, and N is the interval length of the discrete Fourier change, and the value N=M, so that:

${\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; j</span>}\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}}$

but

$Z\left(k\right)=\underset{\mathrm{no}=0}{\overset{N-1}{\mathrm{\&Sigma;}}}z\left(\mathrm{no}\right)W_N^{\mathrm{k\; n}}$ k=0, 1, 2..., N-1

The time-domain extraction method is used to decompose the N-point discrete Fourier transform into short Fourier changes to reduce the amount of calculation. The above formula is calculated by decomposing the two data sequences of z(n) according to the parity of n to reduce the amount of calculation. Improve efficiency.

The above are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims (6)

1. the measuring method of a bridge structure dynamic displacement and vibration frequency is characterized in that step is:

(1) sets up bridge structure vibration field monitoring system, gather vibration displacement and GNSS time synchronously; Utilize the tracing mode of automatic total powerstation to gather bridge structure vibration displacement information, the time of utilizing the GNSS signal receiver to gather the high-precision GNSS time synchronously and upgrade the automatic type total powerstation;

(2) coordinate system projection conversion; At first calculate the projective parameter between local coordinate system and the bridge coordinate system, then institute's geodesic structure vibrational coordinate projection is transformed into the bridge coordinate system;

(3) filter bridge structure vibration displacement rough error; Prior imformation according to the bridge structure vibration arranges the displacement boundary value, excluding gross error; According to the temporal information in the each row of data record, filter the identical data line of temporal information that causes owing to the data recording mistake;

(4) linear interpolation method is to the vibration displacement resampling; According to the nominal sampling rate of automatic type total powerstation, adopt the method for linear interpolation that institute's measurement information is carried out resampling, repair missing value;

(5) the employing Chebyshev filter separates quasistatic part and the dynamic part in the displacement;

(6) adopt fast Fourier methods analyst vibration signal frequency spectrum; Respectively x (n), y (n), z (n) the displacement sequence measured are carried out spectrum analysis, obtain vertical, horizontal, the vertical vibration frequency of bridge structure.

2. the measuring method of bridge structure dynamic displacement according to claim 1 and vibration frequency, it is characterized in that, described step (2) is with coordinate and the time (E of monitoring point in local coordinate system, N, H T) is transformed into coordinate and time (x in the bridge coordinate system, y, z, t), adopt following formula (1) to carry out the coordinate projection conversion:

$\left[\begin{array}{c}{x}_i\\ y_i\\ z_i\\ t_i\end{array}\right]=\left[\begin{array}{cccc}\cos \mathrm{\&alpha;}& \sin \mathrm{\&alpha;}& 0& 0\\ -\sin \mathrm{\&alpha;}& \cos \mathrm{\&alpha;}& 0& 0\\ 0& 0& 1& 0\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{c}{E}_i\\ N_i\\ H_i\\ T_i\end{array}\right]---\left(1\right)$

I=1 in the formula, 2,3 ..., N, N is the record total amount, α represents the position angle of monitored bridge 8 y directions in local coordinate system:

α＝arctan[(E ₂-E ₁)/(N ₂-N ₁)] (2)

α represents the position angle of monitored bridge y direction in local coordinate system, (E in the formula ₁, N ₁), (E ₂, N ₂) be 2 coordinates in local coordinate system on the bridge floor y direction; Local coordinate is monitored bridge location rectangular coordinate system commonly used; The bridge coordinate system is to be the x direction with the bridge longitudinal axis, is the y direction with the bridge transverse axis, is the rectangular coordinate system of z direction with the bridge vertical pivot.

3. the measuring method of bridge structure dynamic displacement according to claim 1 and vibration frequency, it is characterized in that, carrying out described step (1) before, make the temporal resolution of automatic type total powerstation bring up to 0.01s by 1s earlier, and at standard baseline demarcation automatic type total powerstation, obtain its range finding addition constant.

4. the measuring method of bridge structure dynamic displacement according to claim 1 and vibration frequency is characterized in that, the idiographic flow of described step (1) is: in first datum round prism is set, as backsight point; 360 ° of prisms are installed in monitoring point at the bridge floor that is positioned at the monitored bridge on the river and/or bridge tower, settle an automatic type total powerstation in second datum, and at GNSS signal receiver of the top of automatic type total powerstation installation, known D coordinates value according to first reference point, second reference point, utilize the first benchmark null circle prism orientation, build a station at the monitoring scene, form the four-dimensional vibration monitor system that comprises three-dimensional vibrating displacement and GNSS temporal information.

5. the measuring method of bridge structure dynamic displacement according to claim 1 and vibration frequency is characterized in that, the idiographic flow of described step (4) is: adopt approach based on linear interpolation to repair missing value, t ₁The moment and t ₂Omit t shift value constantly constantly, the shift value in the calculating t moment (x, y, z):

$\left\{\begin{array}{c}x=x_1+\frac{(t-t_1)x_2-(t-t_1)x_1}{t_2-t_1}\\ y=y_1+\frac{(t-t_1)y_2-(t-t_1)y_1}{t_2-t_1}\\ z=z_1+\frac{(t-t_1)z_2-(t-t_1)z_1}{t_2-t_1}\end{array}\right.---\left(3\right)$

(x in the formula ₁, y ₁, z ₁) be t ₁Shift value constantly, (x ₂, y ₂, z ₂) be t ₂Moment shift value, adopting the nominal sampling rate is the automatic type total powerstation of 10Hz, data recording is spaced apart 0.1s, so value t of the above-mentioned moment ₁, t ₂, t is the multiple of 0.1s.

6. the measuring method of bridge structure dynamic displacement according to claim 1 and vibration frequency, it is characterized in that, the idiographic flow of described step (5) is: choose 0.01Hz for separating the cutoff frequency of quasistatic displacement and dynamic displacement, I type Chebyshev Hi-pass filter is:

$G_n\left(w\right)=\left|H_n\left(\mathrm{jw}\right)\right|=\frac{1}{\sqrt{1+{\mathrm{\&epsiv;}}^2{T}_n^2\left(\frac{w}{w_0}\right)}}---\left(4\right)$

ε is that ripple coefficient, n are exponent number, ω in the following formula ₀Be cutoff frequency, T _n(w/w ₀) expression n rank Chebyshev polynomials:

$T_n\left(\frac{w}{w_0}\right)=\left\{\begin{array}{cc}\cos (n\&CenterDot;\arccos \frac{w}{w_0})& (0\&le;w<w_0)\\ \cosh (n\&CenterDot;\arccos \frac{w}{w_0})& (w_0\&le;w)\end{array}\right.---\left(5\right)$

Design ripple coefficient ε is 0.1, cutoff frequency ω ₀For 0.01Hz, exponent number n are 8, quasistatic part and dynamic part in the I type Chebyshev Hi-pass filter decomposition vibration displacement of passband ripple.

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