Conclusions

Evolutions in earthquake engineering practice by necessity take place in a diverse environment of conflicting social, economic, and technical influences. Any new methodologies or technologies will face resistance until they are perceived to be better than current approaches with equal or greater reliability and similar cost. The case study of the growth in seismic isolation and passive energy dissipation in Japan provides an example of how being in the right place at the right time can lead to broad changes in practice in a short period of time. These technologies were relatively mature prior to the 1995 Kobe earthquake, and the devastating human and economic losses in that event spurred society to look for alternatives to traditional seismic design approaches.

A window of opportunity opened in which the mass media and the development and construction industries educated the general public on the basics of seismic design, and then promoted the newest approaches for earthquake protection to a public that wanted something better.  Although extensive research and performance data from moderate shaking were available that illustrated the potential benefits of seismic isolation and passive damping, advertising and promotion also took advantage of people's anxieties, a fascination with new technology, and the quirk of language in which seismic isolation translates as free from earthquakes. Several implications for promoting improvements in earthquake engineering practice are clear. The first is preparation  a convincing body of technical development needs to be available before a new approach will be accepted by the construction industry and the general public, and there needs to be an infrastructure of human and material resources (e.g., trade associations, manufacturers, equipment) that can be mobilized as demand for their products and services increases. Unfortunately, the second requirement for accelerating change appears to be a damaging earthquake. It is difficult to accept that human and economic losses are necessary to improve current practice, but the window of opportunity that opens in the wake of a severe earthquake allows more education and technology transfer to take place than would be possible in many years of grassroots effort. It is hoped that the results of this work and the insights drawn will further our understanding of the forces at work in order to achieve better seismic protection for our built environment.