The lateral-load resisting systems of many reinforced concrete (RC) school buildings are composed of members controlled by both shear and flexure. The seismic capacity of these buildings should clearly be evaluated by a method that takes into account the dynamic relationships between the strength capacity and ductility as well as the level of earthquake vibrations. The FEMA 310, however, considers the seismic performance of RC buildings composed of members controlled by both shear and flexure by separating them into components of shear walls or moment frames. The seismic performance is then simply based on the heuristic judgment of evaluation standards for each structural type. In the Japanese standard, the seismic capacity of RC buildings controlled by both shear and flexure is quantitatively evaluated either by linear combination or by ellipsoid combination. The Japanese standard, however, does not quantitatively discuss the performance-based seismic level in terms of a desired structural damage state associated with a specific level of earthquake demand. Instead, the level is selected empirically.
Against this research background, the author conducted nonlinear seismic response analyses to investigate the relationships between the strength and ductility of shear and flexural members of RC school buildings to obtain fundamental data for evaluating the seismic capacity of these buildings. The author then compared the strength required of RC school buildings composed of flexural- and shear-failure members to the specific level of ductility of each member based on a nonlinear seismic response analysis. Finally the required strength curves were derived. The curves can be used to predict earthquake damage to a building subjected to a specific earthquake level based on the building’s seismic capacity, which is in turn based on the relationship between the strength capacity of the flexural- and shear-failure members and their ductility. These curves can therefore be used for performance-based seismic evaluations of RC school buildings with dual lateral-load resisting systems.
This report introduces a more efficient and practical methodology for performance-based seismic evaluation for RC school buildings composed of members controlled by both shear and flexure without requiring detailed seismic evaluation such as nonlinear static and dynamic analyses or the capacity spectrum method together with an example of school building in Korea.