Evaluation and Design Requirements for Reinforced Concrete "Gravity" Columns

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9416533 Holmes It has been common practice in building seismic design to assume part of the building resists all the seismic forces and the remainder of the building resists only gravity forces. Though code provisions require the gravity load carrying system to be designed to accommodate the imposed lateral drifts, it is not clear that the procedures for checking the imposed drifts are adequate, and it is not certain that many engineers actually check the gravity system for lateral drifts. Several reinforced concrete (RC) buildings designed in this way sustained damage and collapse associated with failure of the so-called gravity columns (the columns not designed to resist lateral forces). This project is to develop improved understanding of the factors leading to failure of RC gravity columns, as well as to develop improved design approaches. This need is relevant to evaluation and upgrading of existing buildings, and equally relevant to the design of new buildings. The research will address this need using analytical methods based on experimental evidence, and will involve both academic researchers and design professionals. Specifically, the research tasks include: (a) study of the deformability of reinforced concrete columns; (b) study of deformation demands imposed on columns by practical procedures for design and evaluation; (d) transfer of findings to relevant code/guidelines activities; (e) coordination of other Northridge research projects that are related to the ongoing NSF R/R program; and (f) contribution to the professional papers series to be assembled by NEHRP agencies, as well as other publications and professional presentations. This is a Northridge earthquake project. ***