3-D gust effect factor for slender vertical structures

Original studies on gust factor buffeting dealt with the alongwind displacement of structures. Research on this topic carried out since the nineties followed two distinct lines: the first determines the maximum effects due to the alongwind response; the second extends the original method from the alongwind response to crosswind and torsional responses. This paper represents the junction point of these research lines with reference to cantilever slender vertical structures. It derives the most relevant effects associated with the three-dimensional (3-D) wind-excited response of this structural type and shows that a suitable definition of one non-dimensional quantity, referred to as the 3-D gust effect factor, provides such effects at any level through a wide set of experimental, numerical and analytical procedures. A new definition of a 3-D equivalent static force consistent with this method is also introduced and critically compared with previous analogous statements.