Wind-induced vibration of a long span space truss structure
In this paper, characteristic of wind-induced vibration of a a long span space truss structure was studied. Wind tunnel test was conducted in a boundary wind tunnel, based on which displacement along Z direction under all wind directions are discussed, and vibrations of typical nodals are emphasized. It is shown that the upwards corner of the roof may course greater peak displacement in this area than that in other areas. On the other hand, modal vibration of part area may be much greater than that of others, which may enhance the danger of local wind induced structural damage of these areas.
Equivalent static wind loads on large span roof structures
The traditional complete quadratic combination(CQC) approach is accurate enough to analyze the wind-excited vibration problem of large span roof structures.However,the calculation of the equivalent static wind loads(ESWL) for those structures would become more complex since the traditional gust loading factor approach,which is particularly suitable for buffeting analysis and calculation of ESWL on tall buildings,cannot be used to estimate the wind-excited loads on large span roofs due partly to the closely-spaced frequencies and multi-mode coupling encountered in those structures.A new procedure is presented in this paper to calculate the ESWL for the large span roofs.Based on the synchronous multi-pressure measurement on the rigid building model,a new tapping influence coefficient(TIC) approach is firstly proposed to simplify the calculation of the node load vectors,the wind-induced response is then accurately analyzed by CQC approach.By integrating the modal response into the construction of equivalent time-varying loads,the complex wind-induced dynamic problem is simplified to a quasi-static problem,and the ESWL can be finally estimated by LRC approach.The proposed procedure can be used to calculate the ESWL for any complex structures.The calculation of ESWL of an Olympic game gymnasium demonstrates the effectiveness of the present approach.
Calibration of the quasi-static and peak-factor approaches to the assessment of wind loads against the method of Cook and Mayne
Abstract The quasi-static approach to the assessment of peak wind loads assumes that all fluctuations of load are due to corresponding gusts in the approach flow, an assumption known not to hold exactly. The peak-factor approach is a pragmatic approach which seeks to alleviate this deficiency, but which requires calibration. The method of Cook and Mayne, however, assesses the risk of peak wind loads directly in a fully probabilistic manner. This latter method is used to calibrate the two earlier approaches using model-scale data for a range of typical building shapes. The quasi-static approach is shown to perform badly. The peak-factor approach is shown to perform adequately once the calibration factor has been determined.