Exploring the Effects of the Effect of Plan geometry and Twisting Architectural Form on the Seismic Vulnerability of Tall Buildings’ Non-structural Components (NSCs)

According to the global earthquake risk zoning map, the country of Iran is located in a high seismic hazard zone. Therefore, predicting the seismic risk and considering solutions to reduce the vulnerability of buildings against it, is one of the priorities of seismic codes and designers in this field. Tall buildings are, on one hand, essential needs in response to the rapid development and population growth of large cities in Iran, and on the other hand, they have a large volume of Non-structural Components (NSCs), including equipment, facilities, and architectural components. Any damage to these components during an earthquake, including instability, collapse, or even out of service can impose the need for crisis management and emergency service in the city. On the other hand, tall buildings, due to their height and scale, are important buildings and have an impact on the city's landscape and view, and for this reason, designers mostly like to use complex forms with complicated and impressive geometric in the design of these buildings. Referring to this issue, this article investigates the effect of twisting form as one of the common complex forms in the construction of tall buildings on drift and lateral displacement as indicators of measuring the vulnerability of non-structural components and the weight per unit area of the structure as an indicator of the optimal structural design of buildings. For this purpose, twisting forms with regular geometric plans, including triangles, squares, hexagons, and circles, each with degrees of relative twisting of the floors from zero to 3 degrees and with heights of 160, 180, and 200 meters have been investigated. This research is of quantitative type and has been done by modeling method with Rhinoceros architecture software and Karamba3D finite element simulator and analysis plugin. The results of this study show that twisting of the floors in the forms of triangular and square plans shape causes an increase in the amount of drift and lateral displacement and the weight of the unit area of the structure, and the intensity of this increase grows with the height of the building. On the other hand, the twisting of the floors on the forms with Circle and Hexagonal plans has a very little and even insignificant effect, and none of the investigated indicators cause a significant increase.