- Author
- Stone, W. C. | Taylor, A. W.
- Title
- Seismic Performance of Circular Bridge Columns Designed in Accordance With AASHTO/CALTRANS Standards.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD Federal Highway Administration, McLean, VA
- Report
- NIST BSS 170, February 1993, 129 p.
- Distribution
- Available from Government Printing Office Available from National Technical Information Service
- Keywords
- bridges (structures) | columns | standards | circular bridge columns | damage index | design applications | dynamic analysis | earthquakes | hysteretic damage model | inelastic modeling | reinforced concretes | seismic loads | site specific response | soil amplification | spiral reinforcement | seismic design
- Abstract
- Limitations of present procedures for the design of bridge columns to withstand seismic loads are discussed. An integrated seismic design procedure is developed which 1) allows the automatic selection and scaling of design earthquakes given the earthquake magnitude, the distance from the site to the fault, and the type of overlying soil strata; 2) predicts the inelastic behavior of reinforced concrete bridge columns when subjected to random lateral loads up to and including failure; and 3) calculates cumulative damage which can be directly correlated to observed states of damage in laboratory tests of bridge columns. Techniques for achieving the above capabilities are described and new design criteria, based on acceptable damage indices as functions of earthquake magnitude, distance, and structural importance, are proposed. Using the proposed procedure and criteria the performance of 72 representative bridge columns designed in accordance with 1992 CALTRANS specifications is analyzed. Analysis parameters included earthquake magnitude, distance from epicenter, subsurface soil characteristics, column aspect ratio, and normalized column axial load. Design charts, based on allowable damage index versus earthquake magnitude, are developed and retrofit strategies are discussed for those designs which do not meet the proposed design criteria.