Seismic performance objectives and quantitative deformation limits for superimposed RC shear walls with embedded bracings

Abstract

To achieve performance-based evaluations for superimposed RC shear walls with embedded bracings (SRCXSW), their seismic performance objectives and quantitative deformation limits are established in this research based on the presentation of the seismic fortification targets and the parametric analysis of deformation limits by OpenSees. Research results exhibit that the seismic fortification targets proposed in this paper can meet the criteria of “Three-level Seismic Fortification Objectives” as stipulated in Chinese regulations, while also accommodating the owner’s desired performance requirements. The deformation indexes of SRCXSW are notably insensitivity to the arrangement of embedded bracings, the volume stirrup ratio and the reinforcement ratio in boundary element, while can be substantially affected by the axial load ratio and aspect ratio. In contrast to the longitudinal reinforcement and stirrup ratio in hidden columns, the volumetric ratio of the embedded bracings exerts a much more pronounced influence on the deformability of SRCXSW. Subsequently, an appraisal of the suggested deformation limits for SRCXSW, in conjunction with those outlined in current assessment codes, is carried out. It is common to observe inadequate safety margins when utilizing the deformation limits for cast-in-place RC shear walls in Eurocode 8 and ASCE/SEI 41. Conversely, the deformation limits proposed in this paper for SRCXSW are robust and offer ample safety margins for practical engineering applications.