Seismic performance of concrete-filled tubes with restrained plastic hinge zones

The post-buckling performance of concrete-filled tube columns (CFT) under earthquake loads is governed by the deterioration rate of the tube plates in the plastic hinge regions. This study is focused on the improved performance of CFT members by utilizing pairs of tie rods at possible plastic hinge locations to restrain relative plate deformations after members are locally buckled. Results from combined axial and lateral load tests show that the tie rods effectively restrained the development of excessive plate deformations and delayed local buckling. It was found from comparisons that member strength and stiffness were not influenced by the application of tie rods. The test results also confirmed that the energy dissipation capacities of members with tie rods were significantly enhanced. (C) 2002 Elsevier Science Ltd. All rights reserved.