Direct displacement-based design method (DDBD) applied to reinforced concrete frame-wall systems

Abstract

This paper presents an application of the direct displacement-based design (DDBD) to a reinforced concrete frame-wall system (structures that utilize both frames and walls to resist earthquake actions in parallel). Firstly, the mathematical model is presented alongside a description of the methodology applied to determine the design displacement profile and strength proportion between walls and frames. Knowledge of the displacement profile and some recommendations for the combination of frame and wall damping components enables representation of the structure as an equivalent single-degree of freedom (SDOF) system. Secondly, the DDBD method is used to analyze and design a 12-storey building in which the displacements, storey-drifts, base shears, as well as the wall and frame strengths are determined. Then, some guidelines are presented to design the reinforced concrete structures, specifically those related to the stiffness used for the strength distribution and capacity design. Finally, a nonlinear time-history analysis is implemented in RUAUMOKO 2D, using three records from the Maule earthquake which are consistent with the displacement spectrum contained in the Chilean seismic code requirements (Supreme Decree N° 61). These analyzes demonstrate that the DDBD method provides a robust estimation of the displacement demands expected during a seismic event.