The effects of mass irregularity percentage, soil-structure interaction and soil type under the foundation on the seismic performance of medium bending steel frame buildings

Document Type : Original Article

Authors

1 Master's degree in civil engineering-structure, Department of Civil Engineering, Technical and Engineering Faculty, University of Mohaghegh Ardabili, Ardabil, Iran

2 Associate professor, Department of Civil Engineering, University of Mohaghegh Ardabili, Ardabil, Iran

10.22065/jsce.2024.437080.3333

Abstract

This article examines the seismic performance of mid-range steel flexural frame buildings with different mass irregularity percentages designed in accordance with Iranian and foreign valid regulations. For this purpose, a 6-story building located on type C soil and for the Tehran region, which has a very high earthquake risk zone, has been considered for study. Assuming that the investigated buildings were built on type C soil and on type D soil, 22 records far from the fault were analysised in terms of soil-structure interaction and different mass irregularities in height at two levels of DBE and MCE earthquakes. These buildings are simulated in OpenSees finite element software where the nonlinear behaviour of geometry and materials is considered. The results showed that in structures with rigid and flexible foundations, under two levels of earthquake in two types of soil C and D with any type of mass irregularity, the values of relative displacements and acceleration have different patterns. So that the irregular mass changes (decrease and increase) have changed the amount of relative displacements in the lower floors of the structure compared to the regular state (decrease and increase, respectively). While in the upper floors, relative displacements have been created with irregular mass changes (decrease and increase), change (increase and decrease, respectively). In all classes of the irregular structure compared to the regular structure, increasing or decreasing the irregular mass will increase and decrease the absolute acceleration values, respectively. By changing the type of soil from state C to state D, the responses of buildings increase. In general, taking into account the type of local soil (type D instead of C) has increased the amount of relative displacements with less mass irregularities and acceleration by 50% and the amount of relative displacements with more mass by 65% on average.

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Articles in Press, Accepted Manuscript
Available Online from 26 April 2024
  • Receive Date: 22 January 2024
  • Revise Date: 02 April 2024
  • Accept Date: 26 April 2024