Structural response of large stadium roofs due to dynamic wind actions

The paper presents the experimental tests carried out in the Boundary-Layer Wind Tunnel (BLWT) for the design of large roofs of the new Olympic stadium (Karaiskaki) in Pyraeus (Greece), Manfredonia (Italy) and "Delle Alpi" of Turin (Italy). In addition, a report about some results of the T.D. dynamic response analyses performed on the Karaiskaki structure and on the Olympic stadium in Rome will be given. The peculiar shape of these large structures and their particular location (two of them are in the immediate sea vicinity) let arise the question about the actual distribution of the wind loads, i.e. on the pattern of pressure coefficients (cp) over the entire roof. For every wind direction investigated, the following quantities have been evaluated: mean values of the aerodynamic coefficients cp, standard deviation of cp, maximum and minimum values of cp. Finally, the recorded data have been used for the numerical simulation of the dynamic response of the structure in Time Domain, whose aim is the definition of the design loads of the steel lattice struc-tures. A numerical model of the "Delle Alpi" stadium is also in preparation, allowing re-sults of dynamic response analyses, which are still in progress.