Utah Engineers Journal 2021 Issue

50 Photograph 1. Partial Unreinforced Bearing Wall Collapse in Salt Lake City. Photo: Corey Price, Reaveley Photograph 2. Unreinforced Masonry Wall Failure in Downtown Salt Lake City. Photo: Spenser Heaps, KSL Photograph 3. Unreinforced Masonry Apartment Building With Collapsed Parapets and Damaged Chimney. Photo: SHPO Continued from the previous page Figure 5. Population Exposure Modified Mercalli Intensity (MMI) Scale https://earthquake.usgs.gov/earthquakes/eventpage/ uu60363602/pager Damage from the Magna earthquake was widespread in Salt Lake County. While the total economic losses are distorted due to ongoing business disruption from the COVID-19 pandemic, property damage and loss totals will likely be generated based upon insurance claims and FEMA assistance programs in the future. Structural damage included connection failures at masonry and concrete walls to floor and roof decks — some with a partial collapse at decks, and a partial collapse at a URM bearing wall (Photograph 1), and URM in-plane shear cracking with telltale x-patterns and twisting at corners. At least one instance of a prefabricated metal building connection failure was documented in the EERI Virtual Earthquake Reconnaissance Team report. 12 Many unreinforced masonry chimneys and parapets fell onto the sidewalks and lawns below them from commercial and residential buildings. In the early stages after the earthquake, the Red Cross opened evacuation centers at nearby schools that were ultimately unneeded. Forty-nine homes in the community at the Western Estates mobile home park were placarded as unsafe (red-tagged per ATC-20 evaluation criteria) due to failure of the unit supports (see Photograph 5). Bruce Maison reports that this is notable because each had been anchored, but the anchorage failed during the earthquake. 13 While the collapsed foundations did not result in gas leaks or fire, the overall damage to this community raises an important point of concern for local disaster mitigation efforts. Manufactured housing, which includes mobile homes, is the single largest unsubsidized, affordable housing source in the U.S. It represents over 6% of the country’s housing stock. Protecting these communities from disaster impact is critical to protecting the lives and livelihoods of some of our most socioeconomically vulnerable neighbors.