9520277 Lee To reduce the damages to reinforced concrete columns and to prevent their collapse due to strong multidirectional ground motions, the use of concrete filled tubular (CFT) columns is an attractive option. In 1992, an NSF Workshop for U.S. Japan Cooperative Research on Composite and Hybrid Structures recommended that the CFT column system be one of the four research areas to be emphasized in earthquake engineering research. In recent years a large number of cyclic loading tests on CFT specimens of the circular type has been conducted. These tests were primarily subjected to combined compression and torsion. Results showed that CFT members can deliver high ultimate strength with large ductility. This project will develop appropriate mathematical models through both analytical and experimental investigations to quantify the composite actions of CFT columns under cyclic and earthquake loading considerations. In the experimental program, the scale or volumetric effects and the loading rate effects will both be considered, shaking table tests of three-dimensional CFT columns system will be carried out during the second half of this three-year study. This is a project supported under the year 1 program of the Civil Infrastructure Systems (CIS) solicitation, NSF 94-154. ***
