User-Oriented Architectural Design of Separated Infill Walls to Prevent Soft Ground Story in Reinforced Concrete Low-Rise Buildings

Abstract

Buildings with open ground stories are more vulnerable to soft story mechanisms, which might lead to building collapse in a moderate quake. To mitigate these negative effects, retrofitting techniques typically introduce new structural elements or energy dissipation devices, which increases the deformation capacity of the soft story without modifying the stories above. However, by altering the open nature of the ground floor, these solutions fail to integrate the occupants' preferences and needs into the design process. Therefore, instead of modifying the ground floor, this study will propose a user-centered design process, which is based on separated infill walls in the upper stories, to mitigate the effects of soft story irregularity. The user-centered design strategy integrates the needs and preferences of the occupants into the design solutions of their built environment. To achieve this, two low-rise reinforced concrete buildings in Turkey were selected as case studies and subjected to structural analyses to determine whether the separation of the existing infill masonry walls reduced the lateral strength of the structure. In parallel, preliminary designs of the infill separations was developed and discussed with architects, practicing engineers, and builders. The feedback helped to develop design details to achieve the separation of the infill walls from the frames in the studied buildings. The occupants that live in the existing buildings or the surrounding areas were interviewed and presented with parametric variations of these proposals. Quantitative data suggests that separation of the infill walls is a feasible solution that could be applied to new construction and for existing reinforced concrete multistory buildings and the qualitative data that was obtained from the interviews suggested that user-centered design approaches help to develop suitable seismic mitigation strategies.