Floor acceleration demands for 11 instrumented buildings in Taiwan during the 1999 Chi Chi earthquake

Accurate prediction of peak floor absolute accelerations is a crucial step in defining simplified seismic design procedures for operational and functional components (OFCs) attached to common buildings. A particular characteristic of seismic accelerations is that they increase along the building elevation. The amount of this increase depends on many factors, such as the type of lateral load resisting system, the height of the structure and the input ground motion. The suggested linearly increasing height factor in current design codes is empirical and based on limited observation of recorded data. Some research and observations have suggested that this factor needs revision in order to include the characteristics of the building and input ground motion. This has motivated several countries concerned with high seismic hazards to embark in building monitoring programs. As a part of a project sponsored by the Taiwan Strong Motion Instrument Program (TSMIP), data from 11 extensively instrumented buildings in Taiwan during the 1999 Chi Chi earthquake were compared to modern code provisions. The studied buildings have different lateral load resisting systems and different heights, and they did not suffer any structural damage during the earthquake. Based on acceleration measurements, the article discusses the correlation in the elastic range between the height amplification factor and some of the building characteristics.