Report - PEER - University of California, Berkeley

2.3 Evaluation of Component Damage Measures (DM)The DMs provide explicit descriptions of damage to structural elements, nonstructuralelements, and contents. These descriptions must be relevant and insufficient detail to enable subsequent quantification of the necessary repairs,disruption of function, and safety hazards (e.g., falling hazards, release of hazardoussubstances, etc.). As with the IM-EDP relationships, the associations between EDPand DM should account for uncertainty in the damage predictions.Shown in Figure 3 are examples of conditional fragility relations fornonstructural partition walls, describing the probability of being in a given damagestate as a function of the interstory drift ratio demand. In this case, the three damagestates are predicated on the nature of the repairs to restore the wall to its undamagedstate, i.e., DM1 requires patching cracks and repainting, DM 2 requires replacementof the wall boards, and DM3 requires replacement of the entire partition, wallboardsplus stud framing. The curves shown in Figure 3a are conditional probabilities of thedamage exceeding each damage state, P(DM>dm i |IDR), whereas the curves in Figure3b are the conditional probabilities of being in any one damage state,P(DM=dm i |IDR). The latter form is required for subsequent loss calculations.Using data from previously published tests, new tests, and post-earthquakereconnaissance, PEER researchers have compiled a number of damage fragilitycurves for structural and nonstructural building components and building contents(e.g., Taghavi and Miranda 2003, Aslani and Miranda 2003, Krawinkler 2004, Pagniand Lowes 2004, Hutchinson and Chaudhuri 2004, Eberhard et al. 2001).Assembling these fragility curves is often a major challenge, particularly since muchof the prior testing has emphasized strength and ductility capacity of components,with insufficient attention to damage measures such as residual crack width, spalling,permanent displacement, etc. The hope is that this situation will improve through theestablishment standards and documented examples for data reporting and formattingin a manner that supports modeling needs of the PBEE framework.In many cases the component damage measures are primarily focused onP ( DM | IDR )1.0P ( DM = dm | EDP = edp)1.00.80.6DM1DM20.80.6DM1DM30.40.2DM3(a)0.40.2DM2(b)0.00.00.000 0.005 0.010 0.015 0.020IDR0 0.005 0.01 0.015 0.02 0.025IDRFigure 3. Fragility relationships for drywall partitions for three damagestates conditioned on interstory drift (Krawinkler & Miranda, 2004).20