1. Displacement based approach for the seismic retrofitting of a RC existing building designed for only gravitational loads
- Author
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CANCELLARA, DONATO, DE ANGELIS, FABIO, PASQUINO, VITTORIO, Zhou XG, Chu MJ, Liu JM, Qu SY, Fan HT, Cancellara, Donato, DE ANGELIS, Fabio, and Pasquino, Vittorio
- Abstract
The present paper deals with the evaluation of the level of seismic vulnerability of a Reinforced Concrete (RC) building by using a Displacement Based Approach (DBA), in the context of a performance methodology, and by adopting the N-2 method, according to Italian seismic code NTC 2008. The RC building is located in Southern Italy in an area classified as high seismicity zone and designed, in the past, only for gravitational loads. During the evaluation phase the effect of masonry infills is considered by modeling with a non linear analysis all the panels considered in effective interaction with the structural frame. It is highlighted that in the examined case the masonry infills determine a worsening of the seismic behavior of the existing structure. So that it is illusory that by neglecting these panels a general beneficial effect would be obtained. Moreover in such case the neglect of these panels would have guided to a retrofitting strategy which is completely different and would have not answered to the real needs of the structure. The correct evaluation of the seismic response is finalized to the seismic retrofitting by using a traditional strategy, designed through a displacement based approach, for reducing the displacement demand on the existing structure. The adopted retrofitting strategy is represented by steel braces with steel reinforcement elements for the columns. In the non linear model for these elements it has been considered their confinement action for the reinforced concrete columns. The vulnerability level of the structure and the Safety Factor (SF), defined as the ratio between the displacement capacity and the displacement demand, is calculated for the building before and after the seismic retrofitting.
- Published
- 2012