Numerical simulation approach and seismic performance investigation of self-centering precast concrete frames

Abstract

Self-centering reinforced concrete frames have been extensively studied owing to their minimal residual deformation after major earthquakes. Substantial nonlinear dynamic simulations of self-centering concrete connections have been studied for subassemblies of frames. However, simulations of 3D whole concrete self-centering frame structures are limited. Therefore, in this study, a 3D concrete self-centering frame finite element model was developed based on shaking table tests of a six-story frame to investigate its seismic performance. In addition, a new method similar to the centralized plastic hinge was established to simulate the gap openings at the beam-column and column-base joints of the self-centering structure. A comparison of the simulation and test results, including the maximum roof displacements, connection gap openings, and post-tensioned (PT) strand internal force ratios, demonstrated that the model accurately simulated both local and global responses. Using this benchmark model, this study investigated the distribution of the beam-column connection gap openings on each floor of the structure, which is challenging to measure in tests. Furthermore, this study examined the effects of the initial PT forces in the beam and column strands, as well as the column strand lengths, on the seismic performance of the structure. The simulation results indicated that the gap openings at beam-column joints were uniformly distributed along the floor in the short-span direction, whereas in the long-span direction, they generally decreased with increasing height. Increasing the PT forces in the column strands and decreasing the extension story of the column strands reduced the inter-story drift on the ground floor while resulting in an increase in drift on the upper floors. In addition, reducing the strand length did not significantly decrease the self-centering capacity of the structure.