Resolution No. 4814 - Laserfiche WebLink

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wall construction are common in pre-WW2 construction. Visua~ inspection and the general vintage of building stock in the Eugene/Springfield Metro Area suggest that there are likely significant numbers of buildings in the Eugene/Springfield Metro Area with cripple wall foundations or with unbolted sill plates. Unreinforced masonry buildings are also subject to major damage in earthquakes. The Eugene/Springfield Metro Area has several dozen masonry buildings (most commercial or industrial) which may be unreinforced or reinforced masonry. These buildings may be highly vulnerable to damage and thus should have a high priority for detailed evaluation, especially those buildings with high occupancies or important functions. A detailed inventory of wood frame buildings with the above noted seismic deficiencies and inventory of unreinforced masonry buildings would be useful to further quantify the level of risk posed by such structures in the Eugene/Springfield Metro Area. 10.7 Earthquake Hazard Mitigation Projects: General Examples There are a wide variety of possible hazard mitigation projects for earthquakes. The most common projects include: structural retrofit of buildings, non-structural bracing and anchoring of equipment and contents, and strengthening of bridges and other infrastructure components. The seismic hazard (frequency and severity of earthquakes) is moderate in the Eugene/Springfield Metro Area. However, the risk (potential for damages and casualties) may be fairly high because some buildings and infrastructure may be highly vulnerable to earthquake damages. The risk assessment methodology outlined above for earthquakes provides the basis for identifying the high risk facilities that then become the primary targets for mitigation. Structural retrofit of buildings should not focus on typical buildings, but rather on buildings that are most vulnerable to seismic damage. Priorities should include buildings on soft soil sites subject to amplification of ground motion and/or liquefaction and especially on critical service facilities such as hospitals, fire and police stations, emergency shelters, and schools. Non-structural bracing of equipment and contents is often the most cost-effective type of seismic mitigation project. Inexpensive bracing and anchoring may protect very expensive equipment and/or equipment whose function is critical such as medical diagnostic equipment in hospitals, computers, communication equipment for police and fire services and so on. For utilities, bracing of control equipment, pumps, generators, battery racks and other critical components can be powerfully effective in reducing the impact of earthquakes on system performance. Such measures should almost always be undertaken before considering large-scale structural mitigation projects. The strategy for strengthening bridges and other infrastructure follows the same principles as discussed above for buildings. The targets for mitigation should not be typical infrastructure but rather specific infrastructure elements that have been identified as being unusually vulnerable and/or are critical links in the lifeline system. For example, vulnerable overpasses on major highways would have a much higher 10-17