Seismic Behavior Analysis Of RC Frame Structures With Self-centering Energy Dissipative Rocking Column

Reducing the stiffness of a structure, that leads to reduce the structural accelerations and the component internal forces when subjected to seismic excitation, which defined as “weakening” structure. The structural strength demands decrease when using this idea to design and construct buildings. This is different from using high performance materials, structural components and structural systems to “strengthening” structure. Roh proposed a “rocking column” which is a type of double hinged precast column and placed it on the structure to weakening the structure, and additional the floor diagonal viscous damper to control the structural displacement, ultimately the story accelerations and displacements are decreased.For the rocking columns had less energy dissipation and additional diagonal damper may influence structural function. This paper in the upper and the lower ends of the rocking columns installed a self-centering and energy dissipative in one small corner brace, constitute a self-centering energy dissipative rocking column. Small corner brace not only use the relative deformation between column and beam or the foundation to energy dissipation, but also can decrease structural residual displacement under seismic excitation. The main contents and conclusions of this paper are as follows:1. Established the finite element model of rocking columns, and in different axial compressive ratio respectively lateral loading to overturn reciprocating five times. The overall shape of force-displacement curve is similar to Roh proposed rocking column four line force- displacement(moment- curvature) curve, and Open Sees can better simulate the negative stiffness. So it can better simulate the rocking behavior of the column. Comparing with the traditional column, it is found that the rocking column has the same lateral stiffness as the traditional column before the softening stage of the rocking column.2. Analyzed the hysteretic performance of different axial compression ratio self-centering energy dissipative rocking column and free rocking column under the low cyclic loading. The analysis shows that, free rocking column has less energy dissipation and suffer the impact of axial compression ratio. Self-centering energy dissipative rocking column has good energy dissipation and not suffer the impact of axial compression ratio, and the hysteretic performance of corner brace showing the non symmetry.3. Based on Open Sees platform, elastic plastic dynamic time history analysis of five reinforced concrete single pin frame model under different intensity of ground motion is investigated. The analysis shows that, the RC frame with self-centering energy dissipative rocking column reduced story acceleration and residual displacement compare with traditional frame; and floor displacements and story drifts are slightly less than the traditional framework under rare earthquake level.4. IDA analysis of the RC frame with self-centering energy dissipative rocking column and the original frame under the far-field and near- field earthquake was done. And the vulnerability analysis for two kinds of frames is based on IDA analysis and drawing the different limit failure state fragility curves. The analysis shows that, the RC frame with self-centering energy dissipative rocking column has better seismic performance than the traditional frame; no matter far-field or near-field earthquake, installation self-centering energy dissipative rocking column frame the probability beyond the failure limit state is less than the traditional frame.