seismic risk assessment for portugal

Vitor Silva1,2, Helen Crowley2, Humberto Varum1, Rui Pinho3

1 University of Aveiro, Portugal2 GEM Foundation, Italy3 University of Pavia, Italy

Seismic Risk Assessment for Portugal

Current Seismic Hazard and Risk assessment in Portugal

‣ Portugal is located in a region with low to moderate seismic hazard;

‣ National building portfolio is characterized by a large fraction of masonry construction;

‣ Various Studies already exist regarding the seismic risk assessment in Portugal (LNEC, IST, FEUP, UA, UMinho);

‣ Present study represented a chance to investigate new PSHA models, up-to-date building portfolio and new vulnerability model.

‣ Test the open-source software from the Global Earthquake Model initiative.

Probabilistic Seismic hazard model for Portugal

‣ Hazard model proposed by Vilanova and Fonseca in 2007

Probabilistic Seismic hazard model for Portugal

‣ Consideration of a large logic tree structure

‣ Ground motion models from Akkar and Bommer (2010) and Atkinson and Boore (2007)

Probabilistic Seismic hazard for Portugal

Development of an up-to-date Exposure Model

‣ Strongly based on the CENSUS Survey of 2011

‣ Building distribution at three administrative levels

Development of an up-to-date Exposure Model

‣ Buildings have been organized in terms of construction materials, number of storeys and time of construction (design level)

Development of an up-to-date Exposure Model

‣ Buildings have been organized in terms of construction materials, number of storeys and time of construction (design level)

1985 - 2011

A

B

C

A

B

D

C

1960 - 1985

Development of an up-to-date Exposure Model

a) Reinforced concrete b) common masonry c) weak masonry

Probabilistic Seismic hazard model for Portugal

Development of an up-to-date Exposure Model

1x1 km2

Development of an up-to-date Exposure Model

‣ Two exposure models with different spatial resolutions

Development of a new fragility/vulnerability model

‣ For reinforced concrete (bare-frame) structures, 200 drawings were analyzed

Development of a new fragility/vulnerability model

‣ RC 2D frame representative of a building typology

Development of a new fragility/vulnerability model

100 ground motion records

Development of a new fragility/vulnerability model

‣ Fragility models following two damage criteria

Inter-storey driftGlobal drift

Development of a new fragility/vulnerability model

Development of a new fragility/vulnerability model

‣ For masonry typologies, a simpler methodology was employed

Capacity curves from the work of Carvalho et al. 2002 were combined with the capacity Spectrum method (Freeman, 2002) to derive sets of fragility curves

Seismic risk for Portugal

‣ Probabilistic losses for a 475 years return period (parish resolution)

Seismic risk for Portugal

‣ Probabilistic losses for a 475 years return period (gridded resolution)

Seismic risk for Portugal

‣ Disaggregation of losses per building typology

What can one do with these results?

‣ Identification of the regions where risk mitigation measures should be applied;

‣ Understanding of the expected average annual losses to establish insurance

premiums;

‣ Development of insurance mechanisms (e.g. TCIP);

‣ Identification of the building typologies contributing to the total losses, and

recommend retrofitting interventions;

‣ Evaluation the effectiveness of the current design regulations in terms of

economic losses;

‣ Employ the direct losses (seismic risk) in an integrated risk evaluation (socio-

economic vulnerability/resilience)

Seismic Risk Assessment for Portugal

Thank you

Except where otherwise noted, this work is licensed under: creativecommons.org/licenses/by-nc-nd/4.0/

Please attribute to the GEM Foundation with a link to - www.globalearthquakemodel.org