Effects of Soft Story Locations on the Nonlinear Time History Analysis of Multistory Reinforced Concrete Buildings

The current paper included studying the effects of soft storey locations on dynamic response of reinforced concrete (RC) buildings under the impacts of earthquakes. Soft storey is essential to provide the building with a functional space such as vehicle garages or open meeting rooms. Further analytical investigation was necessary to understand the impact of these flexible floors on the building's response during earthquakes, as conducting experimental research to address this issue is highly difficult. The research encompassed the effects of soft storey location in two types of buildings, one with equal spans and the other with unequal spans, on the nonlinear time history response. Each building consists of a 10-stories (G+9) RC residential structure subjected to earthquake effects. The analysis was carried out using program sap2000 v23. An analogous diagonal strut was used to illustrate the infill panels. The study included the effect of soft storeys on the natural period, the change in base shear with time, and the change of displacement and acceleration along time for each building. The obtained results showed that including a soft storey in the analysis for buildings having either equal or unequal spans increased the time period, displacement, and storey drift, causing a decrease in the acceleration and base shear forces. Building with the soft storey on the fifth floor (at the mid-height of the building) showed a better dynamic response compared with that using the soft storey on the ground and last floors.