Kobe Earthquake

The results were decidedly mixed, but the failures costly_most retaining walls along the port failed, and the related ground settlement pulled buildings and other structures apart. .
             Buildings .
             The large commercial and industrial buildings in the Kobe area, particularly those built with steel or concrete framing, are similar to buildings of the same vintage in California. The Japanese building code had a major revision for concrete-frame buildings and a more limited revision for steel-frame buildings in 1981. The Uniform Building Code, as used in California, had major changes in 1973, 1975, and several times since then. The current Japanese code requires that buildings in Japan be designed for somewhat higher force levels than does the Uniform Building Code. Both areas require design for much higher forces than most other earthquake regions of the world. .
             Typically, pre-1981 concrete-frame buildings performed very poorly in Kobe, with many collapses. Post-1981 buildings performed much better_some were extensively damaged, but most had light damage. The buildings that fared best, and those without significant damage, had extensive concrete shear walls. .
             As in other earthquakes, large commercial and industrial steel-frame buildings performed better than any other type. However, major damage and a few collapses were observed. Pre-1981 steel buildings had most of the serious known damage. Certain innovative types of steel buildings, including high-rises, had very serious damage, and collapses might have occurred if the duration of the earthquake had been a few seconds longer. .
             Building owners usually do not understand that the earthquake provisions of even the strictest building codes do not necessarily have reasonable performance criteria for larger and stronger earthquakes. The current regulations, including those for all of California, are typically written with the expectation that in a strong earthquake a building will be severely damaged_in fact, it is assumed the building may need to be torn down, but it should not collapse.