Common irregularities and its effects on reinforced concrete building response

Abstract

In most of the countries, the irregular building construction is popular for fulfilling both aesthetic and functional requirements. However, the evidence of past earthquakes in Nepal and the globe demonstrated the higher level of seismic vulnerability of the buildings due to irregularities. Considering this fact, the present study highlighted the common irregularities and its effect on reinforced concrete building response. The effect of structural irregularities was studied through numerical analysis. The geometrical, mass and stiffness irregularities were created by removing bays in different floor levels and removing the columns at different sections respectively. In this study, the numerical models were created in finite element program SAP2000. The structural performance was studied using both non-linear static pushover and dynamic time history analysis. The results indicate that the level of irregularities significantly influenced the behavior of structures.

Response Reduction Factor for Structures with Significant Irregularities on Different Soil Stratum

“…According to some studies, the flexible base condition affects the building's response differently than the fixed base condition, reducing the structure's stiffness and altering the response spectrum [21]. The structure's response is dependent on various factors, including the stiffness of the soil, the structure's dynamic characteristics, damping factor, natural period, mass, and stiffness [22][23][24][25]. In the United States, the amount of scientific investigation considering SSI increased towards the end of the 2000s, with some studies summarized in the FEMA-440 report [6], which considered nonlinear analysis.…”

“…The natural period becomes longer when considering the soil's flexibility, and the characteristics of the footings affect the building's performance [22,7]. Many researchers have studied the influence of irregularities on RC structures' seismic performance, finding that regular buildings have larger roof displacement values than irregular buildings, while non-regular buildings were the first to achieve life safety and collapse prevention [23].…”