A stochastic CSM-based displacement-oriented design strategy for the novel precast SRC-UHPC composite braced-frame in the externally attached seismic retrofitting

Abstract

With the development of performance based earthquake engineering, the recognition of performance based seismic design (PBSD) is continuously growing in academia and industry. Meanwhile, with the gradual awareness of earthquake threat to the existing aged buildings, researchers are focusing more on the novel retrofitting technologies to enhance the structural capacity. Based on this background, a novel precast steel-reinforced-concrete and ultra-high-performance-concrete composite braced-frame is developed for the externally attached seismic retrofitting, and a stochastic capacity spectrum method (CSM) based displacement-oriented design strategy is proposed and well validated via a case study. In general, the novel external composite substructure combines the superiority of substructure technology, precast technology, energy-dissipation technology and high-performance material technology, and is a promising structural form in the seismic retrofitting. The proposed design strategy derives from the classic CSM, and its procedure is in alignment with the PBSD to make the designed building to satisfy various predetermined functional requirements during use. The incorporation of probability factors makes evaluation results more comprehensive and objective, and the control of displacement targets makes structural systems more performant under different demand levels. The case study indicates that the stochastic CSM-based design strategy can be well coupled with the novel external composite substructure during the whole retrofitting process (i.e., three design parts), which demonstrates the superior applicability and stupendous potentials of the proposed design strategy for the subsequent in-depth research.