FULLY SIMULATED NONLINEAR-ANALYSIS OF LARGE STRUCTURES SUBJECTED TO TURBULENT ARTIFICIAL WIND

A fully numerical model is presented for simulating the response of slender structures to artificial wind loading. The deterministic method in the time domain is adopted to evaluate the response of very large systems during turbulent gusts lasting 1 to 10 min. Particular attention is devoted to very high-wind-sensitive systems such as guyed masts, as well as television reticulated towers. For this kind of structure, interaction effects between the loading process and the response process cannot be neglected. This causes an adjunctive nonlinearity of the mechanical problem, which is coupled with the so-called geometric nonlinearity that arises from significant displacements occurring during the phenomenon. The wind loading is artificially generated by simulating the time series of the turbulent wind field in the portion of the atmospheric boundary layer that is of interest for real structures (up to about 400 m). The stochastic processes that simulate the wind speed at given points are generated as multi-correlated time histories having specified auto- and cross-spectra. These must reproduce the characteristics of the turbulence of wind fluctuations in the atmosphere. The structures are supposed to behave nonlinearly and are simulated through discretization with the finite element methods. The characteristics and performances of the model are illustrated by means of two applications.