Reserve seismic capacity determination of a nuclear power plant braced frame with piping

A typical diagonal braced steel frame was developed to determine the amount of reserve capacity that is available beyond elastic design levels. The frame was analyzed first using elastic static and dynamic analyses. The loadings included dead and live load, an equivalent static lateral earthquake load, two response spectra and a suite of eight earthquake time history records. The response spectra used were the Housner and Regulatory Guide 1.60. The time histories represented different site conditions, distances to causative faults and magnitudes. The lateral static load and Housner spectrum represent vintage design criteria, while the R.G. 1.60 and time history analyses reflect current methodology. The elastic limit responses of the structure were determined along with the accompanying threshold peak ground accelerations (threshold g values). The frame was then analyzed using the program DRAIN-2D to perform two-dimensional elastic--plastic analyses for the eight time histories