The Earthquake Engineering Online Archive

Seismic behavior of bridge columns subjected to various loading patterns

Esmaeily-Ghasemabadi, Asadollah; Xiao, Yan

PEER-2002/15, Pacific Earthquake Engineering Research Center, 2002-12, 321 pages (400/P33/2002-15)

As a part of an experimental program investigating the effects of a variable axial load on the seismic behavior of bridge piers, six scaled reinforced concrete bridge columns with circular sections were tested at the Structural Laboratory of the University of Southern California (USC). The primary experimental parameters were the axial load and loading pattern. The loading program included a combination of a constant, proportionally or nonproportionally variable axial load and a monotonic or cyclic lateral displacement. The objectives were to study the effects of different loads and the displacement paths for both the axial and lateral loading directions, to provide the benchmark data for dynamic and large-scale tests, and to evaluate existing material models and analytical methods. The axial load and loading pattern were observed to have significant effects on the flexural strength capacity, the failure pattern, and the ductility and deformation of the columns. The plastic hinge formation was significantly different in the case of a variable axial load, requiring a modification of the existing plastic hinge models. The conventional analytical methods underestimated the flexural strength for high compressive axial loads in a monotonic analysis. Based on the experimental observations, several models for steel and concrete stress-strain behavior and two plastic hinge methods were developed and then employed in a computer program developed to address the analytical needs of the research.

Available online: http://peer.berkeley.edu/publications/peer_reports/reports_2002/0215.pdf