In 2016, an ambitious hotel project was conceived for the state of Nayarit, Mexico by a well-recognized Hotel Chain. This is the highest earthquake region in Mexican Pacific coast. 3 out of 10 buildings of the project were joint existing 7 and 8-storey RC buildings with one of them being partially occupied and the other two with a partial level of Grey Work including some environmental degradation. These existing buildings were not up to date to the latest Mexican seismic regulation requirements brought by the Mexico City 19 sept 2017 earthquake aftermaths, and the structural assessment showed that construction hadn’t followed structural specifications thoroughly in first place. With expected MCE accelerations in the 1.8g-2g vicinity and with tougher minimum strength requirements from the latest seismic regulations update, the retrofit was certainly a challenge. This report is based on the engineers’ work finding a feasible solution:
What will we talk about, why will the audience want to learn about this?
We’ll talk about the alternatives (detailed comparison) engineers explored to solve the problem, from brute strength (shear wall, bracing, ductility) to damping. The audience will want to learn how to ease the process of retrofitting a structure which otherwise would be too costly and perhaps not feasible if trying with traditional techniques or other types of damping technologies. We described the process and the key elements that made the engineers trust in the solution, namely, an actual proof of the assumptions used in the analysis.
Why is this important, new, different, innovative What will the audience walk away with?
They will walk away with a retrofitting technique based on the used of In-line Friction Dampers. By integrating it to the project, structural upgrade of existing elements was minimum when compared with other alternatives. We’ll show how it was the only technique that made the engineers feel comfortable with the energy dissipation assumptions built into the model, though thorough testing. It warranted an IO performance even that engineers first used a very simplistic static procedure to evaluate the effectiveness of the proposal. This was latter confirmed with the NLTH analysis presented in this report
How does this benefit the profession or the audience?
They’ll get introduced to this retrofitting technique that had been successfully used previously in the USA, Canada and other countries. And will continue to nurture the profession with another tool that could help with retrofits that may become unfeasible under traditional techniques,
It will also continue to educate the audience in the advantages of friction damping, but most importantly what are the key elements of keep in mind to avoid common technical pitfalls when using it to ensure proper and safe integration into a project.