چكيده به لاتين
The main purpose of this research is to investigate the performance of self-centering rocking steel braced frame systems exposed to Post-Fire earthquake. In the event of a fire, steel structures are inevitably exposed to high temperatures, If a structural collapse does not occur after a fire, the remaining performance of such structures should be evaluated to determine whether the various members of the steel structure should be destroyed or repaired or used directly in the structure. Therefore, it is necessary to have information about the mechanical properties of steel after fire in order to evaluate the behavior of steel at high temperatures. Due to various reasons, including how the frames are cooled, how much the temperature rises during the fire, how many floors of the frame are under fire, how many floors does the frame have, and whether the fuse and post-tensioned cables are under fire or protected, 32 different scenarios are formed. Now, according to the scenarios defined for the 2D structures of 3, 6, and 9 floors, respectively, which were designed by Mr. Etherton, static and dynamic analyzes have been performed using OpenSees software. In the following, we have discussed the static analysis including push-over and cyclic and the dynamic analysis of the time history, which has been done by applying 10 earthquake records far from the fault at both DBE and MCE levels. These results include the drift of the roof, the residual drift of the roof, the strain of the post-tensioned cables and the shear strain of the fuses in different fire scenarios applied to the structure. According to the results, it can be seen that in the structures of 3, 6 and 9 floors, the most critical scenario is related to the situation where all floors are under fire. Also, the fire effect of the top floor in the self-centering rocking system is greater than other floors due to the connection of the post-tensioned cable to the beam of that floor. In most cases, in scenarios where the same floors are under fire, the scenario where fuses and post-tensioned cables are protected in that structure is more resistant to earthquakes and shows better self-centering performance and if more floors of the structure exposed to fire, the lateral resistance of the structure experiences further reduction.
Keywords: self-centering, Rocking Systems, fire, Post-Fire Earthquake, post-tensioned cable
