Seismic Behavior of Plan and Vertically Irregular Structures: State of Art and Future Challenges

Abstract

Buildings with asymmetry and various classes of irregularity are found to be a major cause for collapses of structure, property loss, and casualties during earthquakes. Such observations have been documented from previous earthquakes that occurred in 1954 in Kern County to two very recent earthquakes in Nepal in 2015 and Imphal (India) in 2016. Although a considerable research effort was directed at asymmetric buildings, well-accepted guidelines for multistory asymmetric structures are still yet to be framed. In fact, the large number of studies on the behavior of asymmetric structures have often yielded contradictory results because of various idealized models and various combinations of influential parameters used particularly in the postelastic range. On the other hand, there is relatively little research on irregular structure (perhaps due to its large variety and difficulty in modeling) available. Possibly due to this reason, the natures of the design provisions of these structures are of a preventive nature rather than a curative one. In this context the present study examines an exhaustive number of studies in the literature in this field to identify the nature of research conducted so that the gaps where the effort is needed to be diverted can be identified. With the mention of the very exhaustive number of literature in this article, the study may prove useful to the researchers to suitably identify a topic for research for framing a set of more general design guidelines for these types of structures.