Seismic input motions for structure, plant and equipment design

The seismic input motions used in the design of nuclear safety related facilities in the UK were developed in the early 1980's. Although there have been improvements to the methodology used since then, the basic definition remains a peak free field acceleration and piece-wise linear response spectra. The increased computing power available to engineers means that the design process can now accommodate a more fundamental definition of the seismic hazard, whilst the increased availability of strong motion records means that ground motion specialists are perhaps now in a position to meet such requirements. The aim of this paper is to stimulate discussion between design engineers and seismologists about how best to harness these advances in technology to overcome any current problems and to identify the co-operation needed to achieve this. (author)