Multi Mushroom Skeleton to Create Rocking Motion in Low-Rise Large Plan Concrete Buildings

Several studies conducted in recent years have shown that the rocking system may be utilized for seismic risk mitigation of buildings in earthquake-prone regions. Currently, it is believed that low-rise buildings adopt the sliding motion over the rocking one due to their small aspect ratio as compared to the high-rise ones. Since lowering seismic response in the rocking system is more efficient than the sliding one, introducing a rocking motion to low-rise buildings is desired. Previously, a type of structural system known as “mushroom buildings” was proposed to do this by removing the border columns at the base level of the building, which would enable the structure to rock on its central bays. In this research, a new system, defined as multi mushroom, is proposed for wide, low-rise buildings by in-plane division of the structure into equal parts. The performance assessment of the proposed system is achieved by comparing a set of multi-mushroom structures with other conventional buildings. The seismic response of these buildings is evaluated using numerical analysis of two groups of scaled earthquakes records. The findings have indicated that the addressed approach mainly shows an immediate occupancy level, while the traditional model has collapsed under some loading cases. however, the base shear and absolute acceleration were both increased when a multi-mushroom structure was used.