Lessons Not Learned from the Catastrophic Collapse of Highway Structures in the 1989 Loma Prieta Earthquake

Most of the damage sustained from the 1989 Loma Prieta Earthquake in Northern California was not a surprise to civil engineers and knowledgeable building officials. As early as the 1900s, engineers knew that unreinforced masonry buildings, and buildings built on poorly compacted soils are serious earthquake hazards. And the 1971 San Fernando Earthquake taught us that multiple deck highway structures similar to the infamous Cypress structure are incapable of sustaining lateral loads produced by seismic shaking. Not only the types of vulnerable structures were known, but what was needed to be done to improve their seismic strength was known as well. Although engineers and government officials realized that the earthquake threat to Northern California was real and anticipated, very little real effort was undertaken to correct deficiencies that were known to threaten lives and produce substantial damage. The reasons for this inaction are numerous and semilegitimate, and the blame for it should be shared by the public who refused to pay the high cost of earthquake preparedness, by government officials who had their priorities in the wrong order, and by the engineering community who had historically opted not to play an active role in government and public policy.