Optimal Design Safety As a Risk Communication Tool

The optimal design safety concept is discussed to be used in a risk communication for the seismic safety of buildings as an alternative building approval procedure. The current Japanese regulations are very rigid and yet they are only the minimum requirements, which do not certify the sufficient safety against very rare earthquakes. Conference-based consensus for the degree of safety may be preferred to the minimum requirement safety in matured society. Influences of various parameters, such as the damage levels, the variability of loads, the failure consequences, the global environmental effects and the service lifetime, on the optimal design safety are demonstrated.