CN102721523B - Method for establishing interval wind spectrum model - Google Patents

Abstract

The invention relates to a method for establishing an interval wind spectrum model and aims to solve the problem that an existing single curve wind spectrum model cannot show the randomness and the difference of the typhoon every time, so that the simulated wind spectrum model can comprise various wind environments in which structures are positioned. The method comprises the following steps of: firstly, obtaining an actual measurement wind spectrum model by carrying out power spectral analysis on a great amount of wind characteristic actual measurement data; secondly, finding out each maximum peak point and minimum peak point of the actual measurement wind spectrum model in a frequency domain, wherein the peak points correspond to different frequency values; and finally, fitting an upper limit spectral curve of the interval wind spectrum model according to all the maximum peak points and fitting a lower limit spectral curve of the interval wind spectrum model according to all the minimum peak points. Obviously, the interval wind spectrum model can obtain an analysis result capable of reflecting a more real condition and has obvious advancement and reliability, and thus, the interval wind spectrum model established by the method can guide the development tendency of the wind spectrum model in the future and can more accurately guide the wind-resistant design of the engineering structure.

Description

A kind of method for building up of interval wind spectrum model

Technical field

The present invention relates to a kind of interval wind spectrum model method for building up based on field actual measurement results, be particularly useful in engineering structure Wind resistant analysis, obtain the residing interval of wind spectrum model in works place.

Background technology

Disaster caused by a windstorm is that one the most frequently occurs in disaster, and the casualties and the economic loss that are caused by it are huge.Calculate by German statistical data, world's disaster caused by a windstorm causes annual loss to reach 137.7 hundred million dollars.Add in recent years, Global climate change is larger, and it is more rampant that typhoon seems.Study characteristic and the effect of wind to structure of wind load, can strengthen the wind loading rating of structure, reduce disaster caused by a windstorm loss, thereby there is very important meaning.

Engineering structure wind characteristic mainly comprises average wind characteristic and fluctuating wind characteristic.Because wind spectrum model can accurately reflect the size that in fluctuating wind, each frequency content is done to contribute, because of but main parameter in fluctuating wind characteristic.The field measurement of near-earth boundary layer high wind characteristic can obtain wind environment the most directly, the most real data, because of but grasp the most effectual way of somewhere wind characteristic.Also all according to field actual measurement results, matching obtains existing famous wind spectrum model.Professor Davenport just once records matching according to more than 90 high wind that different location, differing heights place record in the world and obtains horizontal fluctuation wind speed spectrum.

In recent years, along with the raising of the continuous attention to monitoring structural health conditions and engineering structure measuring technology level, on a lot of large bridges, health monitoring systems has been installed both at home and abroad.Comprise Foyle beam bridge and the Flintshire cable-stayed bridge etc. of the Skarnsunder cable-stayed bridge of Japanese alum strait Bridge, Norway, the Sunshine Skyway cable-stayed bridge of the U.S., Canadian Confedration beam bridge, Britain abroad.China comprises the blue or green Ma Qiao in Hong Kong, moistens and raise bridge, Jiangyin Bridge, Shanghai Xu Pu bridge, Lu Pu bridge, Nanjing Yangtze River Bridge, yangtze river in nanjing two bridges, Binzhou Huanghe River Highway Bridge etc.These monitoring systems, for grasping local wind characteristic, are set up reasonable wind spectrum model effective means are provided.

Due to the impact of the factor such as randomness, geographic position of wind characteristic wind-engaging, the wind spectrum model otherness of at every turn surveying typhoon is very large, and this has obtained checking in long-term site-test analysis.But conventional several pulsating wind power spectrums, if Davenport spectrum, Kaimal spectrum, Karman spectrum and Panofsky spectrum are all single curves, cannot embody randomness and the otherness of each typhoon at present.Therefore, in order to embody better the typhoon characteristic in bridge site district, the wind spectrum model of setting up needs to reflect the randomness of typhoon, can be more reliable with the wind load that makes to simulate, and strong/typhoon is more reasonable as the structures under wind design in control load area.

Summary of the invention

Technical matters: the method for building up that the object of the invention is to create a kind of interval wind spectrum model based on field actual measurement results, this technology is incorporated into interval concept in the middle of the foundation of wind spectrum model, solved to a great extent existing Hypothesis of Single Curve Build Up wind spectrum model and cannot embody the randomness of each typhoon and the problem of otherness, the interval wind spectrum model simulating can comprise the residing all kinds of wind environments of works.

Technical scheme: for the problems referred to above, first the present invention carries out power spectrumanalysis by the wind characteristic measured data to a large amount of and obtain actual measurement wind spectrum model; Secondly each peak point of finding out actual measurement wind spectrum model in frequency domain, these peak points comprise maximal peak point and minimum peak point, corresponding to different frequency values; Finally simulate the upper limit of interval wind spectrum model according to all maximal peak point, simulate the lower limit of interval wind spectrum model according to all minimum peak points.Address the above problem adopted technical scheme flow process as follows:

The first step: carry out a large amount of violent typhoon field measurements:

Measurement method has two kinds, and one is during typhoon, estimates typhoon time of arrival, anemoscope is placed in to span centre or the tower top of Longspan Bridge, adjusts frequency acquisition and carries out the collection of wind speed and direction data; Another kind is by being arranged on structural healthy monitoring system---the anemoscope in SHMS carries out the collection of wind speed and direction data, and the data of acquisition system collection are sent to monitoring center by transmission system;

Second step: actual measurement wind speed and direction data are carried out to power spectrumanalysis, obtain actual measurement wind spectrum model:

The air speed data sample collecting is carried out to analyzing and processing, select the bigger than normal and subsample stably of one section of wind speed, based on matlab large data process software, adopt power spectral density estimation method, write power spectrum density calculation procedure and calculate, obtain the power spectrum density of actual measurement air speed data, taking x axle as frequency, y axle is power spectrum density, and curve plotting is the wind spectrum model of surveying air speed data;

The 3rd step: each peak point of finding out all actual measurement wind spectrum models in frequency domain:

Actual measurement wind spectrum model is all the very large curve that fluctuates, and every curve all exists a series of peak point, and these peak points comprise maximal peak point and minimum peak point, corresponding to different frequency values;

The 4th step: the maximal peak point to wind spectrum model and minimum peak point, adopt nonlinear least square method to carry out respectively matching, to obtain the bound of interval wind spectrum model;

To every a bit of wind spectrum model, the down wind power spectrum expression formula that still code requirement specifies is carried out matching, that is:

$n{S}_u/{\left(u^{*}\right)}^2=a{f}_z/{(1+{\mathrm{bf}}_z^{1/m})}^{\mathrm{cm}}$ Formula 1

$f_z=\mathrm{nz}/\stackrel{\‾}{U}\left(z\right)$ Formula 2

In formula, S _ufor power spectrum density, u ^*for air-flow frictional resistance speed, f _zfor not peaceful coordinate, for mean wind speed, z is overhead height of anemoscope, the ripple frequency that n is wind, and c gets 5/3, a, b and m for fitting parameter;

In fit procedure, adopt conventional nonlinear least square method, each section of matching parameters obtained a, b and m are different, finally obtain the interval wind spectrum model based on actual measurement wind characteristic.

Beneficial effect: three-dimensional fluctuating wind field stimulation is prerequisite and the basis of wind induced structural vibration response analysis, wind spectrum model is prerequisite and the basis of three-dimensional fluctuating wind field stimulation, thereby most important.In order to carry out structures under wind design and research effectively reliably, just must set up wind spectrum model accurately and reliably according to local actual measurement wind characteristic, wherein must be able to consider randomness and the otherness of wind.This patent is incorporated into interval concept in the middle of the foundation of wind spectrum model, solve existing Hypothesis of Single Curve Build Up wind spectrum model and cannot embody the randomness of each typhoon and the problem of otherness, the interval wind spectrum model of gained can comprise the residing all kinds of wind environments of works, thereby can obtain the analysis result that more reflects actual conditions.Because this patent has obvious advance and reliability, thereby will guide the development trend of following wind spectrum model, be used widely in following structures under wind field.

Brief description of the drawings

The Establishing process figure of the interval wind spectrum model of Fig. 1,

Fig. 2 repeatedly surveys the comparison diagram of wind spectrum model and Kaimal spectrum,

Fig. 3 repeatedly surveys the comparison diagram of wind spectrum model and Kaimal spectrum and interval fitting spectrum.

Embodiment

According to technique scheme, the technology of setting up and the implementation procedure thereof of the interval wind spectrum model based on actual measurement wind characteristic comprise following 4 steps:

1) during violent typhoon, carry out by force a large amount of/typhoon field measurement;

Wind characteristic measurement method has two kinds, one is annual During Typhoon, by paying close attention to weather forecast, estimate the time of typhoon through works scene, ready in advance, carrying fine measuring instrument-anemoscope rushes to the scene and installs, according to the feature of works, select suitable measuring position, be generally span centre or tower top for long-span bridge girder construction, by anemoscope and support is in place and carry out anemoscope height (or stretching out from works surface distance), the adjustment of wind direction, make the wind sample of measuring not disturbed by works as far as possible, the zero degree of adjusting anemoscope is direct north, by transmission line, anemoscope is connected with collecting device and carries out the collection of wind speed and direction data, consider anemoscope model and gather requirement, need to adjust the sample frequency of collecting device, another kind is by being arranged on structural healthy monitoring system---the anemoscope in SHMS carries out the collection of wind speed and direction data, the installation method of anemoscope is with similar above, data acquisition is to realize by the data acquisition system (DAS) in health monitoring systems and data transmission system, the data of acquisition system collection are sent to monitoring center by transmission system, for our Treatment Analysis data providing just.

2) actual measurement wind characteristic data are carried out to power spectrumanalysis, obtain actual measurement wind spectrum model;

By collect strong/typhoon wind speed and direction data sample, by selecting, rejecting, select the large and more stable wind data subsample of wind direction of one section of wind speed to carry out analysis of spectrum, based on matlab large data process software, adopt PSD power spectral density estimation method to write calculation procedure, obtain the actual measurement wind spectrum model of each typhoon.

3) in frequency domain, find out each peak points of all actual measurement wind spectrum models;

By checking and analyzing, find the flex point on actual measurement wind spectrum model curve, concrete grammar is: the first step, to survey the local amplification of wind spectrum model curve, determine the approximate location of each peak point, second step, according to the approximate location of peak point, by the Accurate Analysis of wind spectrum model transverse and longitudinal coordinate being determined to the particular location of each peak point.

4), to maximal peak point and minimum peak point, adopt nonlinear least square method to carry out respectively matching.

For above-mentioned 4 steps are described more clearly, draw the Establishing process figure of interval wind spectrum model, as shown in Figure 1.Now introduce the embodiment of this patent as an example of 4 typhoons raising bridge bridge site district through profit example, specific as follows:

Profit is raised bridge and is built up in 2005, owing to being located in Coastal East China, often has every year violent typhoon process.In recent years, when the process profits such as existing Typhoons " Maisha ", " card is exerted ", " Sang Mei ", " Wei Pa ", " phoenix " and " sea-gull " are raised bridge bridge site district, the anemoclinograph of installing in this bridge SHMS has recorded this Strong Wind Samples in bridge site district.It is carried out to power spectrumanalysis, obtain surveying contrast that Run Yang bridge site district down wind turbulent flow power spectral density function and Kaimal compose as shown in Figure 2.

According to above-mentioned peak picking method, Fig. 2 is analyzed, find whole peak points.For maximal peak point and minimum peak point, select expression formula shown in formula (1) and formula (2), adopt nonlinear least square method to carry out respectively matching.Obtained the upper limit spectral curve of interval wind spectrum model by maximal peak point, obtained the lower limit spectral curve of interval wind spectrum model by minimum peak point, so far, interval wind spectrum model is set up complete, sees Fig. 3.Obviously, the interval wind spectrum model of gained can comprise randomness and the otherness of each typhoon.

After obtaining interval wind spectrum model, just can utilize upper limit spectral curve and lower limit spectral curve to simulate respectively the three-dimensional fluctuating wind field in bridge site district, wind field by upper limit spectral curve simulation gained can calculate the higher limit of wind-induced vibration response, and can be calculated the lower limit of wind-induced vibration response by the wind field of lower limit spectral curve simulation gained.Therefore, the structural response that is calculated gained by interval wind spectrum model is also an interval, instead of certain concrete response.The response meeting that is structure changes in this is interval, obviously more reasonable.Along with wind-induced vibration is towards the future development becoming more meticulous, the rationality of interval wind spectrum model will further be embodied.

Claims (1)

1. a method for building up for interval wind spectrum model, the method comprises the following steps:

The first step: carry out a large amount of violent typhoon field measurements:

Measurement method has two kinds, and one is during typhoon, estimates typhoon time of arrival, anemoscope is placed in to span centre or the tower top of Longspan Bridge, adjusts frequency acquisition and carries out the collection of wind speed and direction data; Another kind is by being arranged on structural healthy monitoring system---the anemoscope in SHMS carries out the collection of wind speed and direction data, and the data of acquisition system collection are sent to monitoring center by transmission system;

Second step: actual measurement wind speed and direction data are carried out to power spectrumanalysis, obtain actual measurement wind spectrum model:

The air speed data sample collecting is carried out to analyzing and processing, select the bigger than normal and subsample stably of one section of wind speed, based on matlab large data process software, adopt power spectral density estimation method, write power spectrum density calculation procedure and calculate, obtain the power spectrum density of actual measurement air speed data, taking x axle as frequency, y axle is power spectrum density, and curve plotting is the wind spectrum model of surveying air speed data;

It is characterized in that the method also comprises:

The 3rd step: each peak point of finding out all actual measurement wind spectrum models in frequency domain:

Actual measurement wind spectrum model is all the very large curve that fluctuates, and every curve all exists a series of peak point, and these peak points comprise maximal peak point and minimum peak point, corresponding to different frequency values;

The 4th step: the maximal peak point to wind spectrum model and minimum peak point, adopt nonlinear least square method to carry out respectively matching, to obtain the bound of interval wind spectrum model;

To every a bit of wind spectrum model, the down wind power spectrum expression formula that still code requirement specifies is carried out matching, that is:

NS _u/ (u ^*) ²=af _z/ (1+bf _z ^1/m) ^cmformula 1

$f_z=\mathrm{nz}/\stackrel{\‾}{U}\left(z\right)$ Formula 2

In formula, S _ufor power spectrum density, u ^*for air-flow frictional resistance speed, f _zfor not peaceful coordinate, for mean wind speed, z is overhead height of anemoscope, the ripple frequency that n is wind, and c gets 5/3, a, b and m for fitting parameter;

In fit procedure, adopt conventional nonlinear least square method, each section of matching parameters obtained a, b and m are different, finally obtain the interval wind spectrum model based on actual measurement wind characteristic.