Seismic Vulnerability and Retrofit Alternatives for Typical Soft-story Buildings in Earthquake Prone Areas

More than 300 buildings were severely damaged during the 19 September 2017 earthquake (Mw=7.1) occurred in Morelos, Mexico. One of the most common structural deficiencies detected was the use of ground level parking that produced soft-story buildings. These structures suffered severe damaged or collapsed. A field visit after the earthquake allowed to collect information about typologies of the damaged buildings and a great number of seismic ground motions. This study analyzes the seismic capacity and demands of typical existing building with a soft-story structure, based on the information collected in Mexico City, and subjecting the building to a family of real accelerograms recorded in this area during the earthquake occurrence. To enhance the seismic capacity of these structures, and to reduce their seismic vulnerability, a retrofit technique based on the addition of energy dissipation devices is analyzed. Results show the most efficient retrofit techniques and the strength and stiffness parameters required to improve the expected seismic behavior of this type of structures, and their applicability to mitigate damage in future earthquakes.