Report - PEER - University of California, Berkeley

5. CONCLUSIONSDerivation of vulnerability functions for a class of structures requires many analyses(tens or even hundreds of thousands), especially when a large number of randomvariables is considered. These will then have to be re-derived for different structuralconfigurations as well as for different repair and/or strengthening methods. In thispaper, a new analytical vulnerability assessment framework based on deriving aResponse Database was proposed. The Response Database is an accumulation of preanalyzedinelastic response of structures with a wide range of stiffness and strength.Therefore, with pre-determined stiffness, strength and a set of records, the databaseprovides mean value and standard deviation of inelastic response quantities of thecorresponding structure without the need for further analysis. The effect of ductilityvariation is included by changing the limit states in the calculation of cumulativeconditional probability.The implications of the success of the developed approach are wide-ranging. Forcases of selection between different retrofitting options, the parameterizedvulnerability functions approach gives rapid estimates of probabilities of variousdamage levels being inflicted onto the structures under consideration, given only thestiffness, strength and ductility for each alternative retrofitting scheme. Additionally,the presented vulnerability assessment methodology enables the analyst to practicallyinvestigate the vulnerability of large number of structural configurations. Therefore,this method blends very well with Consequence-Based Engineering (Abrams et al.2002) where the vulnerability assessment for generic structural systems in a largeregion is sought. This approach is being implemented into the Mid-AmericaEarthquake Center seismic loss assessment system MAEViz.ACKNOWLEDGMENTThe work presented above was undertaken as part of the Mid-America Earthquake(MAE) Center research project CM-4: Structural Retrofit Strategies, which is underthe Consequence Minimization Thrust Area. The MAE Center is a National ScienceFoundation Engineering Research Center (ERC), funded through contract referenceNSF Award No. EEC-9701785.194