Computational Study of Steel-Concrete Hybrid Wind Turbine Tower Seismic Performance

The seismic capacity of wind turbine support towers is of significant concern as wind power provides an increasing proportion of the world's electricity supply. This study presents a computational study on the seismic performance of steel-concrete hybrid towers (SCHTs). The equations that govern the tower-free vibration responses are derived based on Euler-Bernoulli beam theory. The modal results are used in the response spectrum analysis to evaluate the higher-mode effects in the SCHTs. Then, a cantilever beam model capable of capturing the joint opening and closing was developed for structural analyses and calibrated against finite element models. Finally, dynamic time history analyses were conducted for different SCHTs under far-field (FF) and near-fault (NF) earthquakes. These analyses showed that the second mode of SCHTs is more significant for the shear force diagram. Dynamic amplification causes the mean peak base moment from the FF set and NF set to be 1.30-1.45 and 1.37-1.57, respectively, greater than the design spectrum using the same 5% damping.