Analytical evaluation on the behavior of diagrid tall steel buildings under far and near earthquakes with the approach of controlling serviceability and acceleration criteria

With respect to the widespread use of diagrid systems in tall buildings, it seems necessary to investigate the behavior of this structural system. Based on different regulations, it can be found that there is no guidance designing this structural system, and its requirements have not yet been included in the design regulations. Hence, one of the most important purposes of the present study was to evaluate the efficiency of the diagrid structural system as one of the modern structural systems in high-rise buildings. For this purpose, 3 structures of 50, 70, and 100 floors have been modeled. In this research, using 7 earthquake records, including 2 earthquakes in the far area and 5 earthquakes in the near area, time-history analysis was performed. Then, various parameters such as displacement and acceleration of floors and drift of floors and Kimura’s coefficient have been evaluated under the influence of earthquake dynamic loads. Also, the exploitation and acceleration criteria against seismic loads have been evaluated using dynamic earthquake analysis, so that this issue has not been addressed in diagrid structures. Based on the findings of time-history analysis during seven accelerations of earthquake mapping, it was indicated that the drift values between floors of all models in all floors are less than 0.004, except the top 10 floors, but due to the effect of earthquakes in the nearby area, the drift of the 10 upper floor of the structure has exceeded the permissible limit of the regulations. The maximum acceleration of stories in the structure of 50, 70 and 100 story is equal to 2.6, 4.3, and 8.2 cm/s2, respectively. The maximum acceleration of the stories is less than the allowed value of the ASCE 7 regulation, i.e., 20 cm/s2. The maximum drift of stories in the structure of 50, 70 and 100 story is equal to 0.008, 0.011 and 0.018, respectively, which is less than the maximum allowed drift value of the regulation, i.e., 0.02.