Extension of Genetic Algorithm Relationships for Estimating the Global Ductility of EBFs under Near-fault Pulse-type Earthquake

Ductility of the structure is the ability to withstand trans-elastic deformations of the structure without a significant drop in strength. Examining the results of past earthquakes and the damage to structures makes its ductility and supply in the structure an important issue. In this paper, in order to take advantage of the strengths of the design method based on the performance and computational ease of force design methods, frames with 3, 6, 9, 12, 15 and 20 floors have been considered. Then, a large database consisting of 12960 data was generated and designed with the purpose of 3 types of column stiffness and 3 degrees of bracing thinness and analyzed against 20 earthquakes near pulsed faults for 4 different performance levels. Finally, using the genetic algorithm, the experimental relationships corresponding to the coefficients of behavior, global ductility and link beam ductility are presented. The proposed relationships are influenced by geometric characteristics such as the number of floors, the stiffness ratio of the columns, the slenderness of the braces, the length of link beam, and the ductility levels. The results of seismic design using the proposed relationships on structures outside the range of the defined database, in comparison with the force methods, show the accuracy of this method in estimating the seismic needs of divergent bracing frames. It can be concluded that based on the production relations of the database, and the validation of the production relations, the results of the structural design by the resulting relations have an acceptable validity.