The Golden Gate Bridge

Earthquake Engineering Design Recommendations


When it became evident in the late 1940s that code provisions for seismic design were inadequate, the Structural Engineers Association of California, the statewide association, undertook the responsibility to complete a set of earthquake design recommendations.

A decade of work resulted in the Recommended Lateral Force Requirements published in 1959. That document, known as the Blue Book, has been continually updated after each significant earthquake: 1964 Prince William Sound, 1971 San Fernando, 1983 Coalinga, 1987 Whittier Narrows, 1989 Loma Prieta, 1994 Northridge, and 1995 Kobe.

The recommendations have been regularly adopted into the Uniform Building Code and are the basis of most seismic code provisions in the United States. They are also the internationally recognized standards for earthquake design.

SEAONC continues to review current laws, regulations and their implementation to ensure protection for the public and profession against improper use of engineering and to foster proper continuing education and development of the profession.