Glendale (PDF) - Hazard Mitigation Web Portal - State of California

Natural Hazards Mitigation PlanCity of Glendale, CaliforniaSection 6 – EarthquakesLoss estimation for the general building stock is averaged for each census tract. Buildingdamage classifications range from slight to complete. As an example, the building damageclassification for wood frame buildings is provided below. Wood-frame structures comprise thecity’s most numerous building type.Wood, Light Frame:• Slight Structural Damage: Small plaster or gypsum-board cracks at corners of doorand window openings and wall-ceiling intersections; small cracks in masonrychimneys and masonry veneer.• Moderate Structural Damage: Large plaster or gypsum-board cracks at corners ofdoor and window openings; small diagonal cracks across shear wall panels exhibitedby small cracks in stucco and gypsum wall panels; large cracks in brick chimneys;toppling of tall masonry chimneys.• Extensive Structural Damage: Large diagonal cracks across shear wall panels or largecracks at plywood joints; permanent lateral movement of floors and roof; toppling ofmost brick chimneys; cracks in foundations; splitting of wood sill plates and/orslippage of structure over foundations; partial collapse of "room-over-garage" orother "soft-story" configurations; small foundations cracks.• Complete Structural Damage: Structure may have large permanent lateraldisplacement, may collapse, or be in imminent danger of collapse due to cripple wallfailure or failure of the lateral load resisting system; some structures may slip andfall off the foundations; large foundation cracks.Estimates of building damage are provided for "High", "Moderate" and "Low" seismic designcriteria. Buildings of newer construction (e.g., post-1973) are best designated by "High."Buildings built after 1940, but before 1973, are best represented by "Moderate." If built beforeabout 1940 (i.e., before significant seismic codes were implemented), "Low" is most appropriate.A large percentage of buildings in the City of Glendale fall in the “Moderate” and “High”seismic design criteria.HAZUS estimates two types of debris. The first is debris that falls in large pieces, such as steelmembers or reinforced concrete elements. These require special treatment to break into smallerpieces before they are hauled away. The second type of debris is smaller and more easily movedwith bulldozers and other machinery and tools. This type includes brick, wood, glass, buildingcontents and other materials.Casualties are estimated based on the assumption that there is a strong correlation betweenbuilding damage (both structural and non-structural) and the number and severity of casualties.In smaller earthquakes, non-structural damage will most likely control the casualty estimates.In severe earthquakes where there will be a large number of collapses and partial collapses,there will be a proportionately larger number of fatalities. Data regarding earthquake-relatedinjuries are not of the best quality, nor are they available for all building types. Available dataoften have insufficient information about the type of structure in which the casualties occurredand the casualty-generating mechanism. HAZUS casualty estimates are based on the injuryclassification scale described in Table 6-4.2006 PAGE 6 - 38