Seismic performance of composite column with double plastic hinges

A composite column including the reinforced concrete column, steel I-beam embedded in foundation, and strengthening steel plate was proposed in this paper. The seismic performance of the composite column was studied based on experiments and finite element analysis. Results showed that two plastic hinges could be formed at the column bottom and at the upper edge of the strengthening steel plate. Influences of the slenderness ratio, axial compression ratio and strengthening height on the seismic behavior of the composite column with double plastic hinges were analyzed. Compared with a single plastic hinge, the two plastic hinges significantly improved the ultimate deformation, strength capacity, stiffness and energy dissipation capacity of the column, reduced the ultimate stiffness, and effectively improved the seismic performance of the column. A theoretical method to calculate the ultimate deformation and maximum strength capacity of the composite column with optimized double plastic hinges was proposed.