Evaluation of Spectrum Compatible Bidirectional Seismic Input

We investigate 4 methodologies to generate sets of horizontal ground motion components compatible with a target RotD100 spectrum, including amplitude-scaling and different spectral- matching approaches. The sets generated are used as seismic input to bidirectional inelastic time history analyses of circular cross-section reinforced concrete single column piers. It is shown that the traditional approach of separately matching each horizontal component to the target RotD100 generate peak inelastic and total strain energy demands that are substantially larger than the demands imposed by sets of amplitude-scaled records. However, the sets generated by simultaneously modifying both components to direct match RotD100 provoked mean peak inelastic responses closer to the amplitude-scaled sets while reducing the variability in the estimates.