Evaluation and story drift ratio limits of structures with separated gravity- and lateral-load-resisting systems using pushover analysis

Abstract

In recent years, China has strongly advocated the development of prefabricated buildings. To meet the growing demand for housing construction, it is necessary to develop high-rise prefabricated structures. To increase the construction efficiency of high-rise prefabricated structures, an innovative composite structural system with separated gravity- and lateral-load-resisting systems (referred to as an ‘innovative structural system’) was developed, and its seismic performance was evaluated. At the component level, efficient numerical models of the composite frames, reinforced-concrete (RC) shear walls, RC coupling beams, and braces in the innovative structural system were developed using the general finite-element software MSC.Marc. The fragility curves of these components were developed through parametric analysis and a literature review of previous research and database documents. At the system level, through finite-element analysis, the seismic mechanism of the innovative structural system under lateral loads, including the lateral displacement pattern, plastic development pattern, and failure mode, was compared with that of the traditional composite frame–shear wall system. A static pushover analysis was performed, and the displacement response results of the innovative structural system under the maximum considered earthquake strength were obtained. The damage to the components was evaluated via fragility analysis, and the seismic performance of the innovative structural system was compared with that of the traditional system according to the safety factor. The results indicated that for high-rise composite structural systems with separated gravity- and lateral-load-resisting systems under frequently occurring earthquakes, the reasonable range of the story drift ratio limit in design is 1/800 to 1/1000, and a limit value of 1/1000 is recommended conservatively.