Abstract
In this research, the influence of the location, area and shape of the openings on the seismic behavior and performance of the concrete slab roof was evaluated and studied using the finite element numerical method, and recommendations were given for the optimal design. In order to model and analyze slab samples and perform parametric studies, ABAQUS software was used in this research. Studies were carried out based on different parameters such as different positions of the opening in the slab, the placement of the opening in the corner-side-center of the slab, different ratios of the area of the opening to the area of the slab,to be less than and more than 50% and finally different forms of the opening. In order to evaluate the seismic behavior of the slab, the time history dynamic analysis method was used based on the Tabas (Iran) earthquake record. The results of the analysis showed that for the opening located in the corner and on the side of the slab, the conditions were critical, and for the opening located on the edge of the slab (side of the slab), the conditions were more critical. Also, the results showed that the presence of an opening on the side of the slab increased theenergy, force and shear caused by the earthquake to at least 40% compared to other positions of the opening in the slab, and as a result, the most critical conditions related to the placement of the opening in the slab It is considered the edge of the slab. Also, the results of the analysis showed that in the case where the opening surface is more than 50% (slab with a large opening), the condition of the slab's vulnerability is lower, but the maximum energy of the slab with a larger opening is always up to 60% more than the slab with a small opening. Of course, this energy level is related to the early times of the earthquake, and finally, the high ductility of the slab with a larger opening can include better seismic behavior and performance of the slab. Finally, the results of the analysis showed that circular and oval openings and, in general, openings with curved and non-sharp corners have better seismic conditions and performance and experience lower energy values. Trapezoidal opening has better conditions in irregular trapezoidal slabs and square opening has the highest amount of energy among different opening shapes, which is not desirable
