SOFT-STORY IN BUILDINGS SUBJECTED TO EARTHQUAKEEXCITATIONS

摘要

This paper presents a study on the implications of irregular vertical stiffness or strengthdistribution resulting in "soft" or "weak" stories that represent one of the major causes of structural failureduring strong ground motion in regions susceptible to earthquakes. The major findings of this studyindicate that buildings, with regular story heights, designed originally for gravity load combinations maysurvive an earthquake with little or no structural damage, whereas buildings with high first-story willexperience major structural damage at lower levels, especially low rise buildings, on the contrary of what itis commonly perceived. Of particular hazard are low-rise buildings with hinged column bases. The swaymechanism "soft story" formed at lower levels of the high first-story building results in a total collapse, aphenomenon that must be accounted for before putting the structure in service. Remedies to prevent softstorymechanism in existing buildings are also briefly presented.