Field Measurement Of Wind Effect On Long-span Spatial Structure Based On Wireless Sensor Devices

The three main research methods of structural wind engineering are field measurement, lab simulation and theoretical analysis. Lab simulation and theoretical analysis must be validated by field measurement. But very limited number of field measurements has been obtained around the world because of the difficulty. The field measurements around the world were listed and reviewed, and the most difficult thing that restricts the development of field testing is the instrumentation.Hence wireless sensor devices were developed based on the three principles of field measurement data acquisition firstly in this paper.The wireless sensor devices must be calibrated before actual use, so the wind-induced internal pressure theory was introduced to the test. Then a cubic model was made and the devices were calibrated by measuring the internal pressure of the cube in wind tunnel.The choices of the reference pressure of pressure sensor were analyzed, and it was noted that the nature of problem of the reference static pressure is the static pressure field around a building. Thus wind tunnel tests in smooth and turbulent flow, with and without a building were carried out to detect static pressure fields. A dimensionless method was proposed to solve the problem that static pressure can hardly be measured exactly, therefore the distributions of static pressure fields were investigated, dynamic characteristics of different flow areas around a building were analyzed in details by amplitude domain and frequency domain analysis methods, distribution formulas of main directions were given, and then the static and dynamic boundaries were concluded. More CFD investigations of static pressure fields revealed there are two narrow strips of regions near a building which can be used to quickly measure reference static pressure and so be named "static pressure corridor", and the method to find their positions and directions was proposed.CFD simulation was performed to compute a typical three-center cylindrical latticed shell, and the results from the computation and the wind tunnel test was compared, which indicated that the numerical result was closed to the practical mean wind pressure distribution. Based on this, two latticed shells were arranged in parallel and the wind-induced interference effect was investigated, and the result is the same with the static pressure field study.After that, full-scale field measurement of wind effect on the roof of Zhejiang University gym was carried out with self-designed wireless sensor devices. The test indicated that device installation will be much easier and the cost will be reduced with wireless devices, the convenience of wireless devices is impressive.Severe typhoon "Haikui" passed through Hangzhou city in the period of the field measurement, and near4hours data were collected then. Wind characteristics of "Haikui" were generalized from the measured wind velocity data, which can be referenced to the simulation of typhoon in wind tunnel test. Wind pressure characteristics on the roof of Zhejiang University gym was revealed from the measured wind pressure data, non-Gaussian characteristics is noted at all pressure taps, so it must be careful to employ the peak factor approach on long-span spatial structures. The value of the peak factor was recommended in this paper. And the dangerous areas were pointed out if the nowaday wind tunnel analysis method was employed. The power spectrum density figures of wind speed and wind pressure are all different, which implies that fluctuating wind pressure on long-span roof does not depend on fluctuating wind velocity, therefore the quasi-steady approach is not applicable to long-span spatial structure.Device development, device calibration, investigation of field test method, then field measurement on a real building were introduced in detail in this paper, a way out of full-scale field measurement with wireless sensor devices was present, the ideas and the devices here can be referenced to the future field measurement of structural wind engineering.