چكيده به لاتين
Structures in earthquake-prone areas are not subjected to a single seismic event, but also to a seismic sequence consisting of mainshock and several aftershocks. However, the influence of seismic sequence on performance of structures has not been addressed in majority of existing seismic codes. Past studies have shown that the structural response and damage may be significantly increased due to seismic sequence, since the rehabilitation procedure between seismic sequences cannot be essentially possible due to lack of time.Collapse prevention is the first priority in the seismic design of buildings. Recently, earthquake engineering researchers and practitioners have begun to address other seismic performance objectives and to develop systems that ensure structural integrity, enable more rapid repair and provide lower repair cost. These systems are able to concentrate all damage in a ductile element, which is disposable and relatively easily repaired, allowing the main structure, including the gravity load resisting system, to remain essentially elastic and undamaged. The Linked column Frame System (LCF) is an example of such a system. Park-Ang damage index is considered to be one of the most realistic measures of structural damage. Thereby, Park-Ang damage index applied in this research.
In this study, three linked column frames with 3, 7, and 11 stories that respectively represent short, medium, and high-rise structures are designed in ETABS2016 software according to Iranian seismic codes (standard no. 2800) and are modeled in OpenSEES software. After the design of the samples, individual and sequential critical seismic scenarios with/without successive shocks, are selected and the Park-Ang damage index of linked column frames are calculated from the results of nonlinear Dynamic Analysis. Finally, the Park-Ang damage index of the frames are obtained and are compared under single and successive earthquake records.The results show that due to the reduction of stiffness and strength of the structure caused by the first seismic shock, In most linked column frames, the park-ang damage index ratio shows an increased rate under successive earthquakes comparing to the individual one. This indicates the need to consider the phenomenon of seismic sequencing in the analysis and design of structures. Also, by examining the trend of maximum damage at the height of the floors, the LCF system can be replaced by determining the damage-sensitive floors.In this dissertation, the middle classes have been identified as vulnerable.
