Title: Analytical Evaluation of Bridge Columns with Double Interlocking Spirals

Author(s): Juan F. Correal, M. Saiid Saiidi, David Sanders, and Saad El-Azazy

Publication: Structural Journal

Volume: 104

Issue: 3

Appears on pages(s): 314-323

Keywords: column; shear; stiffness; test; ties

DOI: 10.14359/18621

Date: 5/1/2007

Abstract:
A study was conducted at University of Nevada, Reno, Nev., on the seismic behavior of double interlocking spirals columns to determine the effects of the shear level, spiral distance, and crossties. The experimental studies consisted of shaketable testing of six large-scale column models until failure. The effect of different parameters was evaluated based on damage progression and the measured data. The analytical studies included the evaluation of plastic hinge length, lateral force and displacement relationships, shear capacity, development of a nonlinear shear stiffness model, and design recommendations for supplementary crossties. The test results indicated that an upper limit on the distance of spiral sets of 1.5 times the spiral radius is appropriate, but supplementary crossties are needed when the shear level is moderate or high. The study also showed that the proposed analytical method to estimate the postyielding shear stiffness provides a close estimate when it is compared with the experimental data.