Investigation of Forward Directivity on Seismic behavior of Mid-Rise Reinforced

Document Type : Research Paper

Authors

1 Ph. D. of Structural Engineering, Khatamol Anbia Resercher

2 Ms.c. of Structural Engineering, Alaodoleh Semnani Institute of Higher Education, Garmsar, Iran

Abstract

The characteristics of earthquakes vary both in terms of amplitude and frequency of content for sites at distances close to the seismic spring and far from it. However, the 2800 standard, which is used as the basis for the seismic design of the country, does not exclude the effects of the near-fault field on loading, and therefore the necessity of studying and comparing such effects on the response of structures is very necessary. Studies on the behavior of structures under the influence of near-field earthquakes have shown that the tracing of these types of earthquakes has more effects on structures (including permanent displacement and directional effects) than accelerations far from faults. Therefore, in order to estimate the near-active faults of earthquakes, the features of the near-earthquakes should be considered in the analysis and design of structures. Accordingly, in this research, we tried to study the effect of directional earthquakes near the seismic response of mid concrete structure using time histories analysis. For this purpose, firstly, the records of the various stations of the quake were determined as the basis for the selection of accelerometers, and then using the analytical methods, the response spectrum of this acceleration, taking into account the directional effect and without it, as well as the pulse isolated from these records In two directions north-south and east-west. Then, according to the time history analysis on two mid concrete structures with the number of stories 10, for 7 station records of the Taiwan Chichi earthquake, the drainage (relative displacement) of floors in structure was investigated. The results of this study showed that, due to the unpredictable nature of the earthquake, in mide structure, in many cases, the availability of earthquake records has little effect on the response of the structures of the structures, and the effect of the earthquake record on the response of the structure has increased.

Keywords


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