چكيده به لاتين
Most of current seismic risk assessments only take into account the risk of major seismicity. While most seismic aftershocks are so strong that they have the potential to cause catastrophic damage to the structure as well as the deaths of residents. Since in the sequential earthquakes, the follower tremors are generally short of initial seismic, the reinforcement of the structure in this short distance is not possible, and thus the need to evaluate the performance of the damaged structure of the first seismic in the event of subsequent seismicity in order to reduce the risk of the structure, it is felt. Extending structural repairs by concentrating crashes in members whose repairs require a short time is one of the solutions that will bring the structure back to its original state in a short time. Achieving this is possible by adding a fuse to the desired system, which absorbs the energy from the earthquake and prevents damage to the main members of the structure. In the Linked Column Frame “LCF” systems, the concept of fuse is used to focus the damage on links only and allows the framing frame to have at least a minimum elastic deformation under a certain amount of earthquake force. The purpose of this study was to investigate the effect of seismic sequence phenomenon on LCF frame system and compare the results of analysis of these frames with flexural frames. In this regard, the 3-floor steel framing frame of the SAC group structures, which is designed in accordance with the UBC 94, is modeled and evaluated in the OpenSess softwall environment. Comparison of these two systems is done through incremental dynamic analysis and comparison of fragility curves at functional levels of Immediate Occupancy, Life Safety and the level of collapse Prevention of the structure. The results of this study indicate that with the increase of the residual malfunction of the first seismic, the effect of seismic sequence phenomenon on structural capacity reduction will be more pronounced. In addition, the seismic sequence phenomenon leads to an increase in the relative displacement of the floor in both types of instrumentation systems. Also, comparison of fragility curves shows that LCF system performs better against seismic sequence phenomenon at its burial level.
Keywords: Seismic Sequence, Linked Column Frame, Incremental Dynamic Analysis, fragility curve
