URM bearing wall building seismic risk mitigation on the west coast of the United States: A review of policies and practices

Abstract

Unreinforced masonry (URM) buildings are the most common target for seismic risk mitigation programmes, due to their long history of poor seismic performance. While seismic risk mitigation must make use of sound engineering methodologies, good public policy is at the heart of successful programmes. Past URM seismic risk mitigation efforts on the west coast of the United States are summarized herein, as valuable insights have been gained from both successful and unsuccessful programmes. Programme details such as compliance deadlines, retrofit design techniques, and retrofit/demolition rates are provided for cities throughout California, Oregon and Washington states, and the overall observed effectiveness of mandatory versus non-mandatory seismic strengthening programmes is discussed.