INCREMENT OF THE RISK TO DEVELOP A SOFT STORY CONDITION IN MEDIUM RISE BUILDINGS BY IGNORING SOIL-STRUCTURE INTERACTION EFFECTS

Abstract

When a structure is founded in soft soils it is mandatory to include soil-structure
interaction (SSI) effects. Otherwise, important design forces and displacement
might be overlooked. If in addition the structure has the potential to develop a soft
or weak story, the risk might considerably increase. A parametric study was
conducted to obtain the dynamic response of simplified mathematical models
representing real structures of six and eight stories, considering soil-structure
interaction (SSI) effects for soft soils (seismic zone III-a of Mexico City), and using
strength and stiffness balanced configurations between the first story and second
story to represent plausible weak and soft story failure scenarios in one of both
analyzed stories. Likewise, it is presented one way to include satisfactorily SSI
parameters according to the proposed method established in the seismic
guidelines of Mexico City since 1995, in particular those of the most recent building
codes (2004 and 2020).