One of the most devastating earthquakes in the history of Mexico was the earthquake of 1985. The seismic design code of Mexico City was urgently revised just after this earthquake. Furthermore, it was modified in 1987 and 2004, incorporating the earthquake damage analysis results and the latest knowledge on earthquake engineering.
In 2017, the Puebla Earthquake occurred and struck Mexico City. About twenty buildings collapsed, and more than 200 peoples died due to this earthquake. The survey results have found out that most of the buildings that collapsed in this earthquake were designed based on the old seismic code before 1985. Therefore, seismic performance evaluation and retrofit of these old buildings is still one of the significant issues.
In this study, the author investigated the ADAS's potential as dampers to retrofit existing reinforced concrete buildings. The ADAS, which means the "Added Damping and Stiffness," is one type of steel hysteretic dampers. This ADAS damper yields in bending during an earthquake and dissipates seismic energy by its plastic deformation. The original developer devised its shape so that plastic deformation occurs in a broader area without stress concentrating on a specific part.
The author took up one existing public office building and attempted to retrofit it using this ADAS. He carried out earthquake response history analyses and compared the building's dynamic behaviors before and after retrofitting. The results cleared that we could reduce inter-story drift angles by inserting the ADAS in the building.
Finally, the author considered a possibility of the damper's fatigue failure due to long-term earthquake ground motions.
Keywords: Seismic retrofit, Hysteretic steel damper, Inter-story drift angle, floor response acceleration, fatigue failure.