By the EERI Reconnaissance Team.
March 15, 2011. Earthquake Engineering Research Institute.
Today our team of engineers reviewed several unreinforced masonry structures that were previously seismically retrofitted.
The performance of the retrofitted structures varied greatly. The team observed multiple failures in retrofitted connections, as shown in Figures 1 and 2, that had been installed to tie unreinforced masonry walls to floor or roof diaphragms.
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| Figure 1. | Figure 2. |
Later in the day, we visited a complex just outside the Central Business District that was comprised of multiple building types, including a Heritage (Historic) building that was originally constructed in 1881. The new buildings typically performed well with a few exceptions. The older masonry structures exhibited the expected failure modes including shear cracking and the failure of sections of the parapet.
Inside the complex, minor non-structural damage was noted, including broken storm water drainage pipes (Figure 3), displaced ceilings, and fallen suspended equipment. The complex is currently being evaluated by the Owner’s engineers to understand the full extent of the damage, and to determine the best path forward in terms of the required remedial measures.
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| Figure 3. |
Learning from Earthquakes: First person reports
