Performance of Structures During the Loma Prieta Earthquake of October 17, 1989 (Nist Sp 778)

Immediately following the magnitude 7.1 Loma Prieta earthquake of October 17, 1989, a team representing the Interagency Committee on Seismic Safety in Construction surveyed the damage to buildings, utilities and transportation structures. This report is based primarily on the data gathered during the site survey and the results of preliminary analyses of structural failures. Most structures designed in accordance with modern codes and standards performed well without serious structural damage. However, there were many concrete and masonry buildings and highway structures in the San Francisco Bay area which were not designed according to modern seismic design codes and which did not perform well. The majority of damaged structures had not been strengthened to increase earthquake resistance. Except for two deaths from landslides and one from fire, the remainder of the 62 deaths from the earthquake was due to partial or total collapse of older structures. This investigation provided the basis for recommendations to improve design and construction practices for buildings and lifeline structures and to mitigate damage to existing structures in future earthquakes.