Investigating the effect of U-shaped yielding dampers and lead core rubber spacers On the fragility curve of concrete flexural frames in the area near the fault

Abstract

Fragility curves (vulnerability), a useful tool for estimating the risk of urban infrastructures are These curves show the probability of failure for different levels of earthquake intensity. With the help of this Curves can be prioritized for retrofitting by determining the vulnerability of structures. in this The study of four, eight and twelve floor models of reinforced concrete bending frame, considered and yield dampers U-shaped shifter and lead core rubber spacers were added to them. These models of instruments under Incremental nonlinear dynamic analyzes using acceleration records of the near-fault domain with intensities and Different frequency contents are placed in the Sap2000 software and finally the fragility curves of the frames are drawn The obtained results showed that the technique of simultaneous use of U-shaped yielding damper And the lead core rubber separator is a suitable method for strengthening structures against earthquakes; As in most of the models examined in this research, the levels of damage allowed are recommended The regulations for the assessment of vibrations compared to the state without dampers and isolators have been changed to levels that can be used He said that it has performed well under the records of the nearby area and has not experienced much damage They did not show Although the improvement of vibration performance has been evident in all the structures of this research, but This improvement is reduced by increasing the height of structures from 4 to 21 floors, as an example in a 21-floor structure. Corresponding to the intensity of PGA=1g under the records of the area near the fault, 53% probability of serious damage is observed It is possible, while the similar amount in a 4-story structure is less than 21%. while in performance Structures equipped with damper and isolator systems under near-fault domain records usually have 5 damage levels Insignificant, moderate and serious have been observed and the structure has not entered the performance level of serious damage.