The design of bridges rarely includes the effects of vertical accelerations. This results in part to a lack of understanding of the occurrence and amplitude of vertical groung motions. Recent compilations and investigations of vertical ground motions are reviewed in this paper. Currently available data indicates that in the near-source region of an earthquake vertical motions can be considerably stronger than horizontal motions, and both can be more than three times or more greater than assumed for design. Key factors affecting the response of highway bridges are discussed. Recommendations for design and research are also given.

Conference Main Page