Abstract

RUIZ GOMEZ, Sonia E.; JIMENEZ JORDAN, René; SANTOS SANTIAGO, Marco A.  and  ORELLANA OJEDA, Miguel A.. Fragility Assessment of Two Rehabilitation Solutions for a First Soft Story Building Damaged During the 19/S17 Mexico Earthquake. Ing. sísm [online]. 2020, n.102, pp.1-25.  Epub Oct 07, 2020. ISSN 0185-092X.  https://doi.org/10.18867/ris.102.513.

The seismic fragility of a building rehabilitated with different techniques can be very different. Here it is shown that such fragility can be similar when a soft-first story (SFS) building is rehabilitated though concrete jacketing, and alternatively, using buckling restrained braces (BRB). For this aim, it is analyzed a 5-story building with soft first story, located in a site of Mexico City where several structures were damaged during the September 17, 2017 (19/S17) earthquake. The building is constituted by regular R/C moment-resisting frames in the soft story, and confined masonry walls with horizontal steel bars in the upper levels. Three cases are analyzed: S1) which correspond to the original structure with SFS; S2) in which concrete jacketing is used in the columns of the first soft story; and S3) in which steel jacketing and buckling-restrained braces (BRB) are added to the first story; in the cases S2 and S3 the masonry walls are retrofitted with steel mesh and mortar. Ten seismic ground motions are used to excite the structures; they correspond to accelerograms recorded in Mexico City, during the 19/S17 seismic event, in soil with dominant period around 1.0s. Story drifts of the three buildings corresponding to the ten seismic ground motions with different intensities, are presented. Fragility curves of the buildings are calculated for values of the maximum story drifts recommended by the Mexico City Building Code (2017).

Keywords : vulnerability assessment; soft first story; rehabilitation of buildings; energy dissipating devices; buckling restrained braces.

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