WIND-INDUCED RESPONSE OF BEIJING NATIONAL STADIUM

摘要

The Beijing National Stadium is the main stadium for opening and closure ceremony of Beijing OlympicrnGames. To determine the wind load on the large-span roof of the Stadium, the displacement responses of meanrnwind and fluctuating wind are analyzed and the positive and negative gust response factors are calculated. Therncalculated results are used in the structural design of the Stadium.rnIt is very important to ascertain the dominant modes, which makes the largest contribution to the fluctuationrnresponses, and the precision of results, which is dependent to the number of the used modes. With respect to thernlarge-span roof, more than one mode contributes to dynamic displacement response and some dominant modesrnare perhaps high frequency modes. The key problem in the calculation of the fluctuation response is how tornchoose the dominant modes.rnThis paper presents the mode energy participation coefficients of background response and of the resonaternresponse in frequency domain and the method of choosing dominant modes. The wind-induced response isrnusually decomposed into background response and resonate response. The total strain energy expectation ofrnbackground response can be calculated accurately in frequency domain. The energy participation ration of arnmode is equal to the ration of the expectation of the mode strain energy of background response to the totalrnexpectation strain energy. The energy expectation of resonate response is the summation of kinetic energyrnexpectation and strain energy expectation. However, the total energy expectation of resonate response cannot berncalculated. The participation ratio of a mode resonate response can now be defined as the ratio of the energyrnexpectation of resonate response to the total strain energy expectation of background response. Furthermore thernparticipation ratio for translation directions of mode background or resonate response can also be calculated.