Reliability based code making for seismic assessment under gas extraction

R.D.J.M. Steenbergen

TNO, Structural Reliability, Delft, The Netherlands
UGent, Department of Structural Engineering

In the Netherlands shallow earthquakes are induced due to large scale gas extraction from the Groningen gas field. Question is how safe the existing building stock is and if strengthening is necessary. A reliability based assessment of the buildings is needed both on the loading and on the resistance since many uncertainties play an important role. The target safety level defined by the government is an Individual Risk level of 10^-5 per year. In this paper the probabilistic calculation of the individual risk is developed taking into account the various building collapse states. A simplified format is derived, which is the basis of the safety philosophy applied in the Dutch Seismic Code NPR 9998:2020.

Key words: Induced earthquakes, reliability assessment, individual risk, seismic hazard, existing structures, probabilistic design