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Observations of the Behavior of Steel Frame Structures in Historic EarthquakesSince the 1906 Great San Francisco Earthquake, numerous steel buildings have been shaken by strong earthquakes. Most recently, modern welded steel moment frames in the United States and Japan have been subjected to some of the strongest motions ever recorded, exhibiting varying levels of structural performance.The use of structural steel for building construction is a relatively young concept. Numerous factors have contributed to the growth of this market, and in the Western United States the generally favorable performance of Steel Buildings in earthquakes prior to 1994 no doubt played a significant role. Specifically four earthquakes in California and Japan (San Francisco, Kanto, Santa Barbara and Long Beach) during the first part of this century gave engineers confidence in steel as a reliable material for earthquake resistant design. During these events, there were typically fewer problems observed in steel structures as compared with concrete and masonry buildings of similar size and scale. The second half of this century has seen tremendous advances in the understanding go earthquakes and in the design of structures of all types to withstand strong ground motions. As the large urban regions on the west coast of the United States have developed over the past few decades, large numbers of steel buildings have been constructed because of their perceived safety, cost and architectural flexibility. Presented below are brief summaries of steel building performance in California and Japanese earthquakes.
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