RETROFIT OF UNREINFORCED MASONRY CLADDING FOLLOWING THE 2001 NISQUALLY EARTHQUAKE

摘要

The 2001 Nisqually earthquake shook western Washington State and caused significant damage to unreinforced masonry (URM) structures in Seattle. Repairs to damaged URM buildings began shortly after the earthquake. Two buildings, the PacMed/Amazon and Starbucks Center suffered extensive damage to their URM exterior cladding systems. The exterior cladding on the top three floors of the 16-story PacMed/Amazon building was removed brick by brick and reconstructed with a visually identical new cladding system called reinforced veneer. The entire exterior cladding of the nine-story Starbucks Center building was removed and replaced. Part of the building was replaced with conventional brick veneer over metal studs; the remainder was replaced with reinforced brick cladding panels. This paper will briefly discuss the seismological aspects of the Nisqually earthquake and how the region was affected by the event. Subsequently, both the PacMed/Amazon and the Starbucks Center buildings cladding retrofits will be discussed. The discussion will include background information, sustained earthquake cladding damage, the cladding retrofit technique, and the cladding retrofit construction for each building.