Wall-to-floor interaction in RC buildings: Modelling case study

Abstract

Current methods of seismic analysis and design of reinforced concrete (RC) buildings typically consider the walls in isolation from the rest of the building, or rely on rigid diaphragm constraints. However, recent research on wall-to-floor interaction has shown that the coupling between the lateral load resisting system and the gravity system may alter the seismic response of the building and increase design actions on RC walls. Additionally, wall-to-floor interaction can also restrict the elongation of the plastic hinge of the walls, resulting in an increase in wall axial load. To investigate the effects of wall-to-floor interaction, a case-study building that represented a common building typology was modelled. The lateral load resisting system in one direction of the case-study building was composed of a RC wall with columns in close proximity to the ends of the wall. Non-linear fibre-based models were developed representing the lateral load resisting system and a series of pushover analyses were conducted to investigate the effects of interactions between the wall, floor, and columns. The results showed that the interactions increased the system lateral load capacity by approximately 15% when compared to a model without interaction or coupling between members. In addition, the wall shear and axial demands increased by 13% and 49% respectively. A series of parametric analyses highlighted a high dependency on the geometry of the members and layout. Increases of up to 45% of the system lateral load strength and between -200% and +84% of the column axial load were observed.