Abstract Modal transformation techniques are usually adopted in structural
dynamics with the aim of decoupling
the equations of motion. They are based on the search for an abstract
space in which the solution of
the problem results simplified. Analogous transformation techniques have
recently been developed with the aim
of defining a space where a multivariate stochastic process is expressed
by a linear combination of one-variate
uncorrelated processes. This paper proposes a method, called double
modal transformation, by which the dynamic
analysis of a linear structure is carried out through the simultaneous
transformation of the equations of motion
and the loading process. By adopting this technique, the structural
response is obtained through a double series
expansion in which structural and loading modal contributions are
superimposed. Its effectiveness and application
are discussed with reference to two classic wind engineering
problems—the alongwind response and the vortexinduced
crosswind response of slender structures—which provide a wide panorama
of the most relevant properties
of this procedure.
