- Author
- Stone, W. C. | Taylor, A. W.
- Title
- System Identification of Spirally Reinforced Circular Bridge Columns Subjected to Cyclic Lateral Loading.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
- NIST SP 820, September 1991,
- Distribution
- Available from Government Printing Office
- Book or Conf
- U.S./Japan Natural Resources Development Program (UJNR). Wind and Seismic Effects. Joint Meeting of the U.S./Japan Cooperative Program in Natural Resources Panel on Wind and Seismic Effects, 23rd. May 14-17, 1991, Tsukuba, Japan, Raufaste, N. J., Jr., Editors, 269-293 p., 1991
- Keywords
- columns | bridges (structures) | failure modes | earthquakes | tests | system identification | regression rate
- Abstract
- Problems relating to present procedures for the design of bridge columns to withstand seismic loads are discussed and a more rational design procedure is proposed. Central to the proposed analysis method is the requirement for an analytical capacity to predict the hysteretic behavior of reinforced concrete bridge columns when subjected to inelastic lateral loads up to and including failure. A three-parameter model with a nonsymmetric trilinear envelope was used in an initial effort to identify relationships between physical column properties and hysteretic model parameters. A digital database of load-displacement histories was established for circular, spirally reinforced bridge column tests. A system identification analysis was performed on each specimen in which the error in predicted cyclic absorbed energy was minimized. Three parameters, comprising a stiffness degrading coefficient, a strength degrading coefficient, and a pinching coefficient, were employed in this study. Subsequent multivariable least squares regression analyses were conducted to correlate the variation of the three failure model parameters with the specimens physical variables as well as cummulative absorbed energy. Conclusions are presented regarding the sensitivity of hysteretic behavior to certain physical characteristics of circular, sprially reinforced bridge columns.