Effects of Architectural Irregularities on the Seismic Behavior of Buildings

Abstract

Cooperation between the architect and the civil engineer has nowadays become essential in any project for the client’s requests’ sake. This study was made to show this idea’s importance and beneficial consequences. For this purpose, a 40-story dual-system high-rise building has been designed to resist moderate seismic and high wind loads. Three main models were formed: Starting with the net model, which is the regular model, followed by the mass irregularity models that were generated for the luxury floor desires (this irregularity was placed in two different locations, namely at the top and middle position), ending with the soft story irregularity models that were cited in the building’s middle and bottom for the gym floor’s need. The positions for each irregularity were tested and compared to those of the regular model under the effect of seismic load on one hand and under the influence of three different wind loads on the other. The required wind loads studied in this article were assigned from the wind speeds of 80, 100 and 120 mph. For these models’ analysis, RSA using finite element method on ETABS was used.The results exhibited that the peak wind speed this building held was 110 mph for both irregularities. Furthermore, the seismically-designed high-rise buildings might not be safe enough to resist a wind load speed of 120 mph. In addition, the middle location is the most preferable locus for these irregularities to occur regarding wind and seismic loads because of its minor displacement, drift and base shear. Besides, it ensured the economic cost of the mass irregularity ($1,706,380), which is in turn less than that of the top position ($1,790,187). The same applies for the stiffness irregularity cost, requiring a budget of $1,632,310 in the middle position but an expense of $1,676,368 for the bottom locus. Although the irregularity’s perfect location seemed unfamiliar, it pursues the sake of the client, the architect and the civil engineer alike.