Time-scales of Performance-based Earthquake Engineering

Synopsis

Scales of seismic risk may be defined as: (i) real-time, that is during the event; (ii) near-real-time, that is in the aftershock sequence of a major earthquake; (iii) long-term life cycle of degrading structures. This evening meeting will address some research results, which may potentially enhance seismic risk management practice.

(i) The tool to manage seismic risk in real-time is earthquake early warning (EEW). EEW is composed of: seismic instruments, a data processing unit, and a transmission infrastructure spreading the alarm to the end users. This alarm may trigger security actions, manned or automated, expected to reduce the seismic risk in real-time. The key design points for EEW applied to a specific structure are: (a) the EEW-estimated earthquake potential; (b) the available time before the earthquake strikes or lead time; and (c) the system performance associated to the case once the alarm is issued. These issues are discussed in the talk and some results are presented, as well as a prototypal application.

(ii) Major earthquakes (i.e. mainshocks) typically trigger a sequence of lower-magnitude events clustered both in time and space. Because the structural damage from the mainshock may possibly be worsened by damaging aftershocks, the failure risk may be large until the intensity of the sequence reduces or the structure is repaired. The talk will present closed-form approximations for the aftershock reliability of simple damage-cumulating structures. Results show that the developed models may represent a useful tool for risk-informed tagging by stakeholders and decision makers.

(iii) Stochastic modeling of deteriorating structures at the scale of the life of the construction may include continuous degradation of structural characteristics and cumulative damage due to point overloads, such as earthquakes. The talk illustrates age-dependent models for life-cycle structural assessment, in terms of failure probability either absolute or conditional on different knowledge about the damage history.

About the speaker

Professor Iunio Iervolino

Iunio Iervolino is an Associate Professor at the Department of Structural Engineering and a member of the faculty board on the Seismic Risk Ph.D program at University of Naples Federico II. He is also an Affiliate Researcher for the John A. Blume Earthquake Engineering Research Center, Stanford University, USA. His main fields of research are engineering seismology, loss assessment and seismic risk.

Further information

This evening meeting is organised by SECED and chaired by Dr Damian Grant (Arup). Non-members of the society are welcome to attend. Attendance at this meeting is free. Seats are allocated on a first come, first served basis. For further information, please contact Greg James (tel. 020 7665 2229).

The results presented in the talk have been developed within the Strategies and tools for Real-Time Earthquake Risk Reduction project (REAKT; http://www.reaktproject.eu), funded by the European Community via the Seventh Framework Program for Research (FP7); contract no. 282862.