Seismic risk for existing buildings in Switzerland-development of fragility curves for masonry buildings

Seismic verification of existing buildings in Switzerland is currently assessed by the pre-standard 2018. In the seismic evaluation of existing buildings in that document, a minimal acceptable seismic safety must be verified, as well as proportional level of retrofitting measures. The relation between the compliance with code requirements and the risk to people associated with a certain accepted level of casualties are the bases for such verifications. The pre-standard will be soon replaced by the technical code SIA 268/9. The seismic risk calculation procedures in the pre-standard SIA 2018 are intended to be extended to deal with other issues such as calculation of damage risk to properties. To this end, the Federal Office for the Environment (FOEN) has initiated a research project to prepare a framework to calculate the seismic risk for people and properties in Switzerland. The focus of that project in the first phase is on the typical masonry buildings. The study uses both numerical models (based on a mechanical approach) as well as empirical models. The partners involved in that project are the Swiss Seismological Service (SED), the Applied Computing and Mechanics Laboratory (IMAC) of EPFL, and Risk & Safety AG (R&S). The project tasks are divided among the project partners as follows. 1) SED provided the hazard data for 3 locations (Zurich, Basel, and Sion old town). Besides, amplification factors considering local site effects were delivered for the aforementioned locations and Sion Rhone valley, as an extreme case. Hazard data was provided in 2 formats: as a function of spectral acceleration and of EMS-Intensity including percentile curves. 2) IMAC conducted the calculations of fragility curves for 2 benchmark buildings using nonlinear dynamic analysis. Furthermore, to consider record to record uncertainties, fractile values of the fragility curves were also calculated and delivered. IMAC also calculated the compliance factors for each benchmark building. 3) R&S prepared a model to calculate the seismic risk for the studied benchmark buildings combining the hazard data of SED and the fragility curves of IMAC. Moreover, R&S also defined an empirical-based model to calculate seismic risk based on EMS-Intensity data and fragility curves derived from Risk-UE (Milutinovic and Trendafiloski 2003). The process of preparing the risk framework is documented in another report (Jamali and Kölz 2012).

report prepared for the Federal Office for the Environment

Note: The status of this file is: EPFL only

 Record created 2012-11-16, last modified 2018-03-17

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