equal to the direction of the dynamic nodal load; The steps above have been carried out using Mathcad (wind tunnel results), Autocad (areas/direction nodal loads) and Excel (final parameters of nodal loads and dynamic functions). 6. The dynamic functions were entered in ESAPrima Win manually, using Time History Analysis. Each function in EPW consists out of two functions. In order to enter the Fourierline of 10 sinuses, 5 summarized functions are needed. Each sinus-function has 4 parameters (offset, amplitude, frequency and shift). Therefore, for each situation (wind-direction, number of towers) an amount of 50x5x2x4 = 2000 numbers had to be entered. 7. For each nodal load the direction and magnitude (x,y,z) had to be entered. For each nodal load the 5 applicable functions were assigned. 8. A calculation of Eigen frequencies had to be done to make dynamic analysis possible. As a result of the dynamic calculations, the continuous signal of each node deflection or each member force could be shown for the one considered minute. The other possibility of output has been used more often to analyse the effects of the wind. For a group of members a list can be produced of the maximum deflection, force or moment which occurred in the considered minute. By combining these output lists, for each member the unity checks for several mechanisms were calculated. From former studies the critical elements were known. For these groups of members (e.g. all column tubes, all end members of a truss), output lists were produced in ASCII format. This was done for each situation (wind direction, roof open or closed, 1 or 2 towers). For clarity: these values are the maximum values of each member which occurred in the considered minute. In Excel, these ASCII-files were used to combine forces and moments for each critical member or profile (several mechanisms, e.g. N+My+Mz for buckling, Vy+Vz for shear). As a result, the maximum unity check of each member has been derived. These unity checks due to the (dynamic) wind in the new situation (1 or 2 towers) have been compared with the unity checks due to static wind load in the old situation (no towers). Conclusions For the steel frame structure of the roof of the Amsterdam ArenA, a comparison has been carried out between a new situation with one or two large towers directly next to the stadium and a situation without large towers. The wind tunnel tests resulted in an increase of the static wind loads on the roof of up to 30% when the tower(s) is(are) added. It is sure that the existing roof structure can not cope with such increased forces. Using the dynamic analysis, the lack of simultaneity of peak loads and the mass inertia of the structure is incorporated. Consequences of this decision are that a complex and extended calculation is necessary. For this model and these calculations, ESA-Prima Win 3.50 was chosen. In close consultation with the people of ESA, the possibilities and optimal methods were elaborated. The input of the loads and the processing of the results required a lot of manual work and spreadsheet calculations. This indicates that the chosen method is really putting ESA to the test. Never before so many loads and variables were used in one model. We have no doubt that in future versions, the input- and post processing facilities will be adapted to the always shifting boundaries, such as this project. The result of this analysis (dynamic increased loads) is generally that the unity checks are comparable to the ones in the original calculations (with static, lower loads). Since the structure has been designed in a way that left little reserve, only a very small increase of the unity checks is allowable. The final decision whether the increase of loads is acceptable, is still in process at the moment of writing. Project data Nodes: 2834 1D macros: 3868 Members: 6428 Types of profiles: 87 Weight of steel: 3098331 kg Length: 227 m Width: 177 m Height: 72 m 95
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