ACI 341.4R-16: Report on the Seismic Design of Bridge Columns Based on Drift

This report provides a basis for evaluating bridge column drift demands and bridge column performance under simulated earthquake loading. It is intended for practicing engineers and academic researchers. Seismic performance objectives established for bridges are reviewed with an emphasis on bridge column performance states. Examples of column damage in past earthquakes are reviewed. Results from recent research on column performance are adapted to the case of bridge columns having a practical range of transverse reinforcement. These results are summarized in terms of drift limits associated with different performance states as a function of column shear span-depth ratio and axial load ratio, for both rectangular and circular section columns. A static pushover method is presented that accounts for embankment flexibility. A two-span bridge is used as an example to illustrate the evaluation of column performance, the influence of changing column bent configurations (two 5 ft [1500 mm] diameter columns versus three 4 ft [1200 mm] diameter columns), and that larger column drift demands may result when embankment mass and flexibility are modeled.