Design-Oriented Energy Capacity Spectrum Method for Seismic Performance Control of Precast Concrete Structures with Semirigid Connections

Abstract

To effectively control the seismic performance of precast concrete (PC) frames with semirigid connections under strong earthquakes, a damage-oriented energy capacity spectrum method is proposed under the performance-based seismic design (PBSD) framework. The energy dissipation capacity (EDC) spectrum corresponding to an equivalent single-degree-of-freedom (SDOF) system of a PC frame is derived based on the Coffin–Manson low-cycle fatigue model of connections and expressed as a function of the displacement response. The related parameters are experimentally and numerically calibrated. To ensure consistency with the EDC spectrum, the hysteretic energy demand (HED) spectrum is developed based on a pseudo-acceleration spectrum, a ductility spectrum, and two energy spectra. The relation between the connection damage and structural damage is employed to establish the damage-oriented EDC spectra. The performance point is iteratively determined, from the intersection points of the EDC and HED spectra at different damage levels, until the specified objective overall damage performance is satisfied. The implementation of the damage-oriented design procedure on a 12-story PC frame with semirigid connections indicates that the EDC spectra corresponding to the three modes agree well with the predictions, and the overall damage indexes obtained from the time history analyses (THAs) are consistent with those obtained from the solution of the performance points. The damage performance objective for PC frames with semirigid connections can be attained by adjusting the design yield moments of the connections by exploiting their adaptability.