Report - PEER - University of California, Berkeley

describing the economic losses associated with replacement or repair costs andimplications on continued functionality. However, in some cases, the damagemeasures correspond to structural collapse hazards, which are not modeled explicitlyin the analysis. One example of this are fragility models that relate interstory drift tothe loss of vertical load carrying capacity of reinforced concrete slab to columnconnections (Aslani and Miranda 2003). Such connections are usually consideredpart of the gravity load system, and, as such their resistance to lateral earthquakeforces is ignored and they are often not included in the structural analysis model.Event in cases where their lateral resistance is modeled, the slab-column analysismodel is rarely configured to simulate vertical collapse. As described later, lossprocessing of the DM information will depend on consequences of the componentdamage and whether or not significant stability related effects are captured in thestructural analysis simulation.2.4 Loss Modeling and Decision Variables (DV)The final step in the assessment is to calculate DVs in terms that are meaningful fordecision makers, e.g., direct dollar losses, continued functionality and downtime (orrestoration time), and life safety risks. In a similar manner as was done for the othervariables, the DVs are expressed through probabilities of DV conditioned on DM,P(DV|DM). Shown in Figure 4 is an example of a loss function for drywall partitions,where the normalized losses (ratio of repair cost to initial construction cost) areassociated with the three damage states described previously (Figure 3). Often therepair costs will exceed the initial construction costs, due to the construction stagingoperations and the inter-relationship of various building components. For example,DM3 (full replacement of the wall partition) may require work on electrical andmechanical components that are undamaged but inside the damaged wall.When computing losses, it is important keep track of the inter-relationshipsP ( L i | DM i )1.00.80.60.40.20.00.0 0.5 1.0 1.5 2.0Normalized LossDM1DM2DM3Figure 4. Normalized LossFunction for Drywall Partitions(Krawinkler and Miranda 2004).between damage and losses for variouscomponents. The electrical and mechanicalrepair costs associated with DM3 in thedrywall partitions is one example of howdamage to one component may lead torepairs in another. A related example isrepairs to architectural finishes, whichcould either be considered as a costassociated with the repair of structuralelements lying behind the finishes or ofdamage to the finishes themselves. In casessuch as this, there is a danger to doublecount the repairs, and hence, over-estimatethe repair costs. Depending on theoccupancy, damage to building contentsrepresents another important source of21